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Objective: To compare the efficacy of in situ transforming growth factor-beta1 (TGF-beta1)-pretreated periosteum to untreated periosteum for regeneration of osteochondral tissue in rabbits.Methods: In the pretreatment group, 12 month-old New Zealand white rabbits received subperiosteal injections of 200 ng of TGF-beta1 percutaneously in the medial side of the proximal tibia, 7 days prior to surgery. Control rabbits received no treatment prior surgery. Osteochondral transverse defects measuring 5mm proximal to distal and spanning the entire width of the patellar groove were created and repaired with untreated or TGF-beta1-pretreated periosteal grafts. Post-operatively the rabbits resumed normal cage activity for 6 weeks.Results: Complete filling of the defects with regenerated tissue was observed in both the TGF-beta1-pretreated and control groups with reformation of the original contours of the patellar groove. The total histological score (modified O'Driscoll) in the TGF-beta1-pretreated group, 20 (95% Confidence Interval (CI), 19-21), was significantly higher (P=0.0001) than the control group, 18 (16-19). The most notable improvements were in structural integrity and subchondral bone regeneration. No significant differences in glycosaminoglycan or type II collagen content, or equilibrium modulus were found between the surgical groups. The cambium of the periosteum regenerated at the graft harvest site was significantly thicker (P=0.0065) in the TGF-beta1-pretreated rabbits, 121 microm (94-149), compared to controls, 74 microm (52-96), after 6 weeks.Conclusions: This study demonstrates that in situ pretreatment of periosteum with TGF-beta1 improves osteochondral tissue regeneration at 6-weeks post-op compared to untreated periosteum in 12 month-old rabbits. [ABSTRACT FROM AUTHOR]

Objective: To determine the potential of periosteal cells to infiltrate poly-epsilon-caprolactone (PCL) nanofiber scaffolds in vivo and subsequently produce cartilage in vitro.Design: PCL nanofiber scaffolds, with or without chitosan-coating were implanted under periosteum in 6-month-old rabbits. Transforming growth factor-beta1 (TGF-beta1) or vehicle was injected into each implant site. After 1, 3, 5 or 7 days, scaffolds were removed, separated from the periosteum, and the scaffolds and periosteum were cultured separately for 6 weeks under chondrogenic conditions. Sulfated glycosaminoglycan (GAG), type II collagen, DNA content, cartilage yield, and calcium deposition were then analyzed.Results: Cell infiltration was observed in all scaffolds. Cartilage formation in the uncoated scaffolds increased with duration of implantation (maximum at 7 days). Cells in the uncoated scaffolds implanted for 7 days produced significantly higher levels of both GAG [560 (95% confidence interval (CI), 107-1013) vs 228 (95% CI, 177-278) microg GAG/microg DNA] and cartilage yield [9% (95% CI, 3-14%) vs 0.02% (95% CI, 0-0.22%)] compared to chitosan-coated scaffolds (P=0.006 or less). There was no significant difference in GAG content or cartilage yield between the TGF-beta1-injected and vehicle-injected scaffolds. However, significantly more mineral deposition was detected in TGF-beta1-injected scaffolds compared to vehicle-injected scaffolds (P<0.0001). Cartilage yield from the periosteum, moreover, was significantly increased by subperiosteal TGF-beta1 injections (P<0.001). However, this response was reduced when chitosan-coated scaffolds were implanted.Conclusions: This study demonstrates that it is possible to seed PCL nanofiber scaffolds with periosteal cells in vivo and subsequently produce engineered cartilage in vitro. [ABSTRACT FROM AUTHOR]

Although silicone radial head arthroplasty has been successful in many patients, it has been associated with complications such as fractures of the prosthesis and silicone synovitis. Synovectomy and removal of the failed silicone radial head, with or without reimplantation of a metallic radial head, is indicated in such complications. In an effort to perform minimally invasive surgery, we performed arthroscopic removal of the silicone head combined with synovectomy in a series of such patients. The silicone prostheses were cut into two or three pieces and then removed. After a median follow up of 26 months, all patients reported excellent pain relief and there were no residual loose bodies. Removal of a failed silicone radial head can be successfully performed arthroscopically. This arthroscopic technique has the advantage of being minimally invasive and can be combined with other procedures including capsulectomy, if necessary. [ABSTRACT FROM AUTHOR]

The success of radial head arthroplasty (RHA) relies on the design of the implant and precision of the surgical technique, with preoperative planning potentially playing a crucial role. The accurate establishment of a patient-specific anatomical coordinate system (ACS) is essential for this planning process. This study tested the hypothesis that an innovative automated method would be an accurate, reliable, and efficient framework to determine the ACS of the proximal radius, which would be a step toward improving the precision of RHA planning. We used advanced computational techniques to analyze 50 forearm CT scans, comparing the accuracy, reproducibility, reliability, and efficiency of the automated method with manually derived ACS using expert observers as benchmarks. The results showed that the automated approach was more accurate in identifying anatomical landmarks, with smaller mean distance discrepancies (0.6 mm) than manual observers (1 mm). Its reproducibility was also superior, with narrower reproducibility limits, particularly for ulnar notch landmarks (0.6 to 0.8 mm compared to manual selection 1.2 to 1.4 mm) (p = .01). In addition, the limits of agreement and the mean absolute rotational and translational differences of the axes were narrower for the automated method, which also reduced the construction time to an average of 46 s compared to 150 s manually (p < .001). These findings suggest that the automated method has the potential to enhance the accuracy and efficiency of preoperative and postoperative computer-assisted procedures for RHA. Further research is needed to fully understand the utility of this automated system for enhancing RHA computer-assisted surgical planning., (© 2024 Orthopaedic Research Society.)

Background: Many distal humerus nonunions are associated with bone loss, and rigid internal fixation is difficult to obtain, especially for low transcondylar nonunions and those with severe intra-articular comminution. The purpose of this study was to analyze the results of a strategy to address this challenge utilizing internal fixation using the Supracondylar Ostectomy + Shortening (S.O.S.) procedure for distal humerus nonunions. The goals of this procedure are to (1) optimize bony contact and compression through re-shaping the nonunited fragments at the supracondylar level with selective humeral metaphyseal shortening, (2) maximize fixation using parallel-plating, and (3) provide biologic and structural augmentation with bone graft., Materials and Methods: Between 1995 and 2019, 28 distal humerus nonunions underwent internal fixation using the S.O.S. procedure at a single Institution. There were 14 males and 14 females with mean age of 47 (range 14-78) years at the time of the S.O.S procedure and an average of 1.7 prior surgeries. Medical records and radiographs were reviewed to determine rates of union, reoperations, complications, and Mayo Elbow Performance Scores (MEPS). Patients were also prospectively contacted to update their MEPS and gather additional information on complications and reoperations. Mean clinical exam follow-up was 17 months, mean clinical contact follow-up was 19 months, and mean radiographic follow-up was 32 months., Results: Four patients did not have adequate follow-up to determine union. Of the remaining 24 elbows, 22 achieved union. Two elbows developed collapse of the articular surface and were converted to a total elbow arthroplasty. There were complications in 10 elbows: contracture (5), superficial infection (2), ulnar neuropathy (1), deep infection (1), and hematoma (1). Twelve elbows underwent reoperation: 4 for contracture release, 3 for hardware removal, 2 for total elbow arthroplasty, 1 for bone grafting, 1 for hematoma evacuation, and 1 for ulnar nerve neurolysis. Compared to preoperative data, there was a significant improvement in postoperative flexion, extension and pronation (P < .01). The mean range of motion was 21° of extension, 119° of flexion, 79° of pronation, and 77° of supination. The mean MEPS was 80 points (range, 25-100 points) and 19 elbows (76%) rated as excellent or good., Discussion: Stable fixation and high union rates are possible in distal humerus nonunions with bone loss using a technique that combines supracondylar humeral shortening, parallel plating, and bone grafting. Secondary procedures are commonly needed to restore function in this challenging patient population., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Intraprosthetic dissociation (IPD) is a complication unique to dual mobility (DM) implants where the outer polyethylene head dissociates from the inner femoral head. Increasing reports of IPD at the time of closed reduction of large head DM dislocations prompted this biomechanical study evaluating the assembly and dissociation forces of DM heads., Methods: We tested 17 polyethylene DM heads from 5 vendors. Of the heads, 12 were highly cross-linked polyethylene (4 vendors) and 5 were infused with vitamin E (2 vendors). Heads were between 46 and 47 mm in diameter, accepting a 28 mm-inner ceramic head. Implants were assembled and disassembled using a servohydraulic machine that recorded the forces and torques applied during testing. Dissociation was tested via both axial pull-out and lever-out techniques, where lever-out simulated stem-on-acetabular component impingement., Results: The initial maximum assembly force was significantly different between all vendors (P < .01) and decreased for all implants with subsequent assembly. Vendor 4-E (Link with vitamin E) heads required the highest assembly force (1,831.9 ± 81.95 N), followed by Vendor 3 (Smith & Nephew), Vendor 5 (DePuy Synthes), Vendor 1-E (Zimmer Biomet with vitamin E), Vendor 2 (Stryker), and Vendor 1 (Zimmer Biomet Arcom). Vendor 4-E implants showed the greatest dissociation resistance in both pull-out (2,059.89 N, n = 1) and lever-out (38.95 ± 2.79 Nm) tests. Vendor 1-E implants with vitamin E required higher assembly force, dissociation force, and energy than Vendor 1 heads without vitamin E., Conclusions: There were notable differences in DM assembly and dissociation forces between implants. Diminishing force was required for assembly with each additional trial across vendors. Vendor 4-E DM heads required the highest assembly and dissociation forces. Vitamin E appeared to increase the assembly and dissociation forces. Based on these results, DM polyethylene heads should not be reimplanted after dissociation, and there may be a role for establishing a minimum dissociation energy standard to minimize IPD risk., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: The purpose of this review is to evaluate the current status of research on the application of artificial intelligence (AI)-based three-dimensional (3D) templating in preoperative planning of total joint arthroplasty., Methods: This scoping review followed the PRISMA, PRISMA-ScR guidelines, and five stage methodological framework for scoping reviews. Studies of patients undergoing primary or revision joint arthroplasty surgery that utilised AI-based 3D templating for surgical planning were included. Outcome measures included dataset and model development characteristics, AI performance metrics, and time performance. After AI-based 3D planning, the accuracy of component size and placement estimation and postoperative outcome data were collected., Results: Nine studies satisfied inclusion criteria including a focus on computed tomography (CT) or magnetic resonance imaging (MRI)-based AI templating for use in hip or knee arthroplasty. AI-based 3D templating systems reduced surgical planning time and improved implant size/position and imaging feature estimation compared to conventional radiographic templating. Several components of data processing and model development and testing were insufficiently covered in the studies included in this scoping review., Conclusions: AI-based 3D templating systems have the potential to improve preoperative planning for joint arthroplasty surgery. This technology offers more accurate and personalized preoperative planning, which has potential to improve functional outcomes for patients. However, deficiencies in several key areas, including data handling, model development, and testing, can potentially hinder the reproducibility and reliability of the methods proposed. As such, further research is needed to definitively evaluate the efficacy and feasibility of these systems., (© 2024. The Author(s) under exclusive licence to SICOT aisbl.)

Objective: Osteochondritis dissecans (OCD) of the capitellum is a joint defect that is common among adolescent athletes. It is important to diagnose OCD as early as possible, because early-stage OCD lesions have a high rate of spontaneous healing with rest. Medical ultrasound could potentially be used as a screening tool for OCD but is limited by the use of delay-and-sum (DAS) reconstruction. In this study, we tested conventional delay-multiply-and-sum (DMAS) and novel low-pass DMAS reconstruction algorithms for better visualization of OCD lesions., Methods: We created phantom and cadaveric OCD models that simulated a range of OCD lesion severities and stabilities. We also imaged an in vivo case of OCD in a patient study. In the reconstructed images, several profiles were taken to measure OCD lesion contrast, cartilage contrast, crack thickness error and bone interface clarity., Results: In the phantom and cadaveric OCD models, we found that histogram-matched conventional DMAS reconstruction improved lesion contrast by up to 16%, cartilage contrast by 26% and bone interface clarity by 15% on average compared with DAS reconstruction. Histogram-matched low-pass DMAS reconstruction improved lesion contrast by up to 22%, cartilage contrast by 45%, and bone interface clarity by 29% on average compared with DAS reconstruction. In the in vivo case of OCD, we found that histogram-matched conventional and low-pass DMAS reconstruction improved lesion contrast by 22% and 26%, respectively., Conclusion: The application of DMAS reconstruction improved the ability of medical ultrasound to detect OCD lesions of the capitellum when compared with DAS reconstruction., Competing Interests: Conflict of interest S.W.O. has received an honorarium for speaking at the annual SIGN conference and receives royalties not related to this research from Acumed, LLC, Wright Medical Group, Inc. and DJO (Aircast Corp.)., (Copyright © 2023 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Purpose: Comminuted radial head fractures are commonly treated by surgical resection or replacement with a prosthesis. A potential problem with radial head replacement is overlengthening of the radial neck ("overstuffing" of the radial head), which has been shown to affect both ulnohumeral kinematics and radiocapitellar pressures. We hypothesized that an overstuffed radial head prosthesis increases capitellar pressure and reduces coronoid pressure., Methods: Seven human cadaveric elbows were prepared on a custom-designed apparatus simulating stabilizing muscle loads, and passively flexed from 0° to 90° under gravity valgus torque while joint contact pressures were measured. Each elbow was tested sequentially with different neck lengths, starting with the intact specimen followed by insertion of understuffed (-2 mm), standard-height (0 mm), and overstuffed (+2 mm) radial head prostheses in neutral forearm rotation, 40° pronation, and 40° supination positions, respectively., Results: Capitellar mean contact pressures significantly increased after insertion of an overstuffed radial head prosthesis. In valgus position with neutral forearm rotation, capitellar mean contact pressure on the joint with an intact radial head averaged 227 ± 70 kPa. Insertion of understuffed, standard-height, and overstuffed radial head prostheses changed the mean contact pressures to 152 ± 76 kPa, 212 ± 68 kPa, and 491 ± 168 kPa, respectively. The overstuffed radial head group had significantly lower whole coronoid mean contact pressures (153 ± 56 kPa) compared with the intact (390 ± 138 kPa) and standard-height (376 ± 191 kPa) radial head groups., Conclusions: An increase in radial prosthesis height significantly increases capitellar contact pressures and reduces coronoid contact pressures., Clinical Relevance: Restoration of the anatomic radial head height is critical when performing radial head arthroplasty to maintain normal joint biomechanics. Elevated capitellar contact pressures can potentially lead to pain and early degenerative changes., (Copyright © 2023 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Background: Arthroscopic debridement for osteochondritis dissecans (OCD) lesions of the capitellum is a relatively common and straightforward surgical option for failure of nonoperative management. However, the long-term outcomes of this procedure remain unknown., Hypothesis: Arthroscopic debridement of capitellar OCD would provide satisfactory long-term improvement in patient-reported outcomes., Study Design: Case series; Level of evidence, 4., Methods: Patients aged ≤18 years who underwent arthroscopic debridement procedures for OCD lesions (International Cartilage Repair Society grades 3 and 4) were identified. Procedures included loose body removal when needed and direct debridement of the lesion; marrow stimulation with drilling or microfracture was added at the discretion of each surgeon. The cohort consisted of 53 elbows. Patient evaluation included visual analog scale for pain; motion; subjective satisfaction; Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) scores; reoperation; and rate of return to sports., Results: At a mean 11 years of follow-up (range, 5-23 years), the median visual analog scale score for pain was 0, and 96% of patients reported being improved as compared with how they were before surgery. The mean ± SD QuickDASH score was 4 ± 9 points (range, 0-52 points), and 80% of patients returned to their sports of interest. The arc of motion significantly improved from 115°± 28° preoperatively to 130°± 17° at latest follow-up ( P = .026). Seven elbows (13%) required revision surgery for OCD lesions, resulting in high rates of overall survivorship free of revision surgery: 90% (95% CI, 80%-96%) at 5 years and 88% (95% CI, 76%-94%) at 10 years. At final follow-up, 7 all-cause reoperations were performed without revision surgery on the OCD lesion., Conclusion: Arthroscopic debridement of grade 3 or 4 OCD lesions of the capitellum produced satisfactory patient-reported outcomes in a majority of elbows, although a subset of patients experienced residual symptoms. The inherent selection bias of our cohort should be considered when applying these results to the overall population with OCD lesions, as we do not recommend this procedure for all patients.

Background: The lateral collateral ligament complex along with the capsule is likely to be at risk during arthroscopic extensor carpi radialis brevis release for lateral epicondylitis. We hypothesized that disruption of the lateral collateral ligament-capsule complex (LCL-cc) would increase the mean contact pressure on the coronoid under gravity varus., Materials and Methods: Eight cadaveric elbows were tested via gravity varus and weighted varus (2 Nm) stress tests using a custom-made machine designed to simulate muscle loads while allowing passive flexion of the elbow. Mean articular surface contact pressure data were collected and processed using intra-articular thin-film sensors and software. Sequential testing was performed on each specimen from stage 0 to stage 3 (stage 0, intact; stage 1, release of anterior one-third of LCL-cc; stage 2; release of anterior two-thirds of LCL-cc; and stage 3, release of entire LCL-cc). The mean contact pressure on the coronoid and the mean ratio of contact pressure on the medial coronoid to that on the lateral coronoid (M/L ratio) were used for comparisons among the stages and the intact elbow., Results: The overall mean contact pressure significantly increased in stage 2 (P = .0004 in gravity varus and P = .0001 in weighted varus) and stage 3 (P < .0001 in gravity varus and P < .0001 in weighted varus) compared with that in stage 0. In contrast, release of the anterior one-third of the LCL-cc (stage 1) did not significantly increase the mean contact pressure on the coronoid in any degree of flexion under gravity varus (P = .09) or weighted varus loading (P = .6). The M/L ratio difference between stage 0 and stage 1 was 1.1 ± 1.1 under gravity varus (P = .8) and 2.1 ± 1.0 under weighted varus (P = .2). The overall M/L ratios in stage 2 and stage 3 were significantly higher than those seen in stage 0 under gravity varus (P = .04 in stage 2 and P = .02 in stage 3) and weighted varus (P = .006 in stage 2 and P < .0001 in stage 3)., Conclusions: Loss of the anterior two-thirds or more of the LCL-cc significantly increases the overall mean contact pressure on the coronoid, especially the medial coronoid, under both gravity varus and weighted varus. The LCL-cc also plays a role in the distribution of coronoid contact pressure against gravity varus loads., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The location (proximal vs. distal) of elbow medial ulnar collateral ligament (MUCL) tears impacts clinical outcomes of nonoperative treatment. The purposes of our study were to (1) determine whether selective releases of the MUCL could be performed under ultrasound (US) guidance without disrupting overlying soft tissues, (2) assess the difference in medial elbow stability for proximal and distal releases of the MUCL using stress US and a robotic testing device, and (3) elucidate the flexion angle that resulted in the greatest amount of medial elbow laxity after MUCL injury., Methods: Sixteen paired, fresh-frozen elbow specimens were used. Valgus laxity was evaluated with both US and robotic-assisted measurements before and after selective MUCL releases. A percutaneous US-guided technique was used to perform proximal MUCL releases in 8 elbows and to perform distal MUCL releases in their matched pairs. The robot was used to determine the elbow flexion angle at which the maximum valgus displacement occurred for both proximally and distally released specimens. Open dissection was then performed to assess the accuracy of the percutaneous releases., Results: Percutaneous US-guided releases were successfully performed in 15 of 16 specimens. The proximal release resulted in greater valgus angle displacement (11° ± 2°) than the distal release (8° ± 2°) between flexion angles of 30° and 70° (P < .0001 at 30°, P < .0001 at 40°, P = .001 at 50°, P = .005 at 60°, and P = .020 at 70°). Valgus displacement between release locations did not reach the level of statistical significance between 80° and 120° (P = .051 at 80°, P = .131 at 90°, P = .245 at 100°, P = .400 at 110°, and P = .532 at 120°). When we compared the values for the mean increase in US delta gap (stressed - supported state) from before to after MUCL release, the proximally released elbows had larger increases than the distally released elbows (5.0 mm proximal vs. 3.7 mm distal, P = .032). After MUCL release, maximum mean valgus displacement occurred at 49° of flexion., Conclusions: US-guided selective releases of the MUCL can be performed reliably without violating the overlying musculature. Valgus instability is not of greater magnitude for distal releases when compared with proximal releases. This findings suggests there must be alternative factors to explain the difference in clinical prognosis between distal and proximal tears. The observed flexion angle for maximum valgus laxity could have important implications for elbow positioning during US or fluoroscopic stress examination, as well as surgical repair or reconstruction of the MUCL., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Continuous passive motion (CPM) has been used for decades, but we are not aware of any randomized controlled trials (RCTs) in which CPM has been compared with physical therapy (PT) for rehabilitation following release of elbow contracture., Methods: In this single-blinded, single-center RCT, we randomly assigned patients undergoing arthroscopic release of elbow contracture to a rehabilitation protocol involving either CPM or PT. The primary outcomes were the rate of recovery and the arc of elbow motion (range of motion) at 1 year. The rate of recovery was evaluated by measuring range of motion at 6 weeks and 3 months. The secondary outcomes included other range-of-motion-related outcomes, patient-reported outcome measures (PROMs), flexion strength and endurance, grip strength, and forearm circumference at multiple time points., Results: A total of 24 patients were assigned to receive CPM, and 27 were assigned to receive PT. At 1 year, CPM was superior to PT with regard to the range of motion, with an estimated treatment difference of 9° (95% confidence interval [CI], 3° to 16°; p = 0.007). Similarly, the use of CPM led to a greater range of motion at 6 weeks and 3 months than PT. The percentage of lost motion recovered at 1 year was higher in the CPM group (51%) than in the PT group (36%) (p = 0.01). The probability of restoring a functional range of motion at 1 year was 62% higher in the CPM group than in the PT group (risk ratio for functional range of motion, 1.62; 95% CI, 1.01 to 2.61; p = 0.04). PROM scores were similar in the 2 groups at all time points, except for a difference in the American Shoulder and Elbow Surgeons (ASES) elbow function subscale, in favor of CPM, at 6 weeks. The use of CPM decreased swelling and reduced the loss of flexion strength, flexion endurance, and grip strength on day 3, with no between-group differences thereafter., Conclusions: Among patients undergoing arthroscopic release of elbow contracture, those who received CPM obtained a faster recovery and a greater range of motion at 1 year, with a higher chance of restoration of functional elbow motion than those who underwent routine PT., Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/G872)., (Copyright © 2022 by The Journal of Bone and Joint Surgery, Incorporated.)

Purpose: To generate an evidence-based opioid-prescribing guideline by assessing the pattern of total opioid consumption and the factors that may predict opioid consumption following arthroscopic release of elbow contracture and to investigate whether the use of continuous passive motion (CPM), as compared to physical therapy (PT), was associated with a decrease in pain and opioid consumption after arthroscopic release of elbow contracture., Methods: Data collected from a randomized controlled trial that compared continuous passive motion (CPM) ( n  = 24) to physical therapy (PT) ( n  = 27) following arthroscopic release of elbow contracture was analyzed for opioid use. Fifty-one participants recorded their daily opioid consumption in a postoperative diary for 90 days. Multivariate analysis was performed to identify factors associated with opioid use. Recommended quantities for postoperative prescription were generated using the 50th percentile for patients without and the 75th percentile for patients with factors associated with higher opioid use., Results: The median total opioid prescription was 437.5-mg morphine milligram equivalents (MMEs) (58 pills of 5 mg oxycodone) and the median total opioid consumption was 75 MMEs (10 pills of 5-mg oxycodone). Twenty-two percent of patients took no opioid medication, 53% took ≤10 pills, 69% took ≤20 pills and 75% took ≤30 pills. Predictors of higher opioid use were preoperative opioid use, age <60 years and inflammatory arthritis. The total opioid consumption appeared similar between the CPM and the PT group. Seventy-five percent of patient's home opioid requirements would be satisfied using the following guideline: Patients undergoing contracture release for osteoarthritis or post-traumatic contracture should be given a prescription for 10 pills of 5 mg oxycodone or its equivalent at discharge. Patients with inflammatory conditions or those taking preoperative opioids should be prescribed 30 pills of 5 mg oxycodone or its equivalent., Conclusion: This study suggests that most patients undergoing arthroscopic release of elbow contracture use relatively few opioid pills after surgery. Use of an evidence-based guideline could decrease opioid prescriptions substantially, while still effectively treating patients' pain., (© 2021 Mayo Foundation for Medical Education and Research.)

Background: There is no consensus how to determine the varus laxity due to the LCL injury using the ultrasonography. There is a risk of lateral collateral ligament injury during or after arthroscopic extensor carpi radialis brevis release for tennis elbow. The equator of the radial head has been suggested as a landmark for the safe zone to not increase this risk; however, the safe zone from the intra-articular space has not been established., Hypothesis: Increased elbow varus laxity due to lateral collateral ligament-capsular complex (LCL-cc) injury could be assessed reliably via ultrasound., Study Design: Descriptive laboratory study., Methods: Eight cadaveric elbows were evaluated using a custom-made machine allowing passive elbow flexion under gravity varus stress. The radiocapitellar joint (RCJ) space was measured via ultrasound at 30° and 90° of flexion during 4 stages: intact elbow (stage 0), release of the anterior one-third of the LCL-cc (stage 1), release of the anterior two-thirds (stage 2), and release of the entire LCL-cc (stage 3). Two observers conducted the measurements separately, and the mean RCJ space in the 3 LCL-cc injury models (stages 1-3) at both flexion angles was compared with that of the intact elbow (stage 0). We also compared the measurements at 30° versus 90° of flexion., Results: At 30° of elbow flexion, the RCJ space increased 2 mm between stages 0 and 2 (95% confidence interval [CI], 1-3 mm; P < .01) and 4 mm between stages 0 and 3 (95% CI, 2-5 mm; P < .01). At 90° of elbow flexion, the RCJ space increased 1 mm between stages 0 and 2 (95% CI, 1-2 mm; P < .01) and 2 mm between stages 0 and 3 (95% CI, 2-3 mm; P < .01)., Conclusion: Elbow varus laxity under gravity stress can be reliably assessed via ultrasound by measuring the RCJ space., Clinical Relevance: Because ultrasonographic measurement of the RCJ space can distinguish the increasing varus laxity seen with release of two-thirds or more of the LCL-cc, the anterior one-third of the LCL-cc, based on the diameter of the radial head, can be considered the safe zone in arthroscopic extensor carpi radialis brevis release for tennis elbow., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This study was funded by the Mayo Foundation for Medical Education and Research (S.W.O.: Principal Investigator). S.W.O. has received nonconsulting fees from SIGN Fracture Care International and royalties from Acumed, Wright Medical, and Aircast. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

Background: Osteochondritis dissecans (OCD) of the capitellum is common in throwing athletes and is believed to result from repetitive overloading on the radiocapitellar (RC) joint, although the cause and mechanism remain unclear. The torsional forces (moments) generated by the triceps during elbow extension pull only on the ulna; therefore, the radial head moves passively across the capitellum and is effectively "dragged along" by the ulna. Any laxity in the proximal radioulnar joint could lead to asynchronous motion between the radius and ulna, resulting in the radial head lagging behind the coronoid and possibly malarticulating with the capitellum during such motion., Hypothesis: Radial head motion on the capitellum lags behind ulnohumeral joint motion during simulated throwing., Study Design: Controlled laboratory study., Methods: A total of 8 cadaveric elbows were tested under simulated throwing, including active extension of the elbow generated by pulling of the triceps under valgus stress, as well as during passive extension under valgus stress to serve as a reference. Ulnohumeral motion was tracked using a video camera. Radial head motion was tracked using an intra-articular, thin-film pressure sensor mounted on the capitellum, and the longitudinal movement of the center of force (COF) of the radial head was measured. Radial head motion was compared between passive and active motion for each 10° of elbow extension from 90° to 20°., Results: Elbow motion during simulated active extension reached an angular velocity of 366 deg/s. Radial head motion during simulated active extension significantly lagged compared with its motion during passive extension at every elbow extension angle examined between 70° and 20° ( P < .001). The maximal lag reached a mean of 4 mm (range, 2-7 mm). In other words, RC and ulnohumeral motion were asynchronous during simulated throwing., Conclusion: This study describes a novel phenomenon: motion of the radial head across the capitellum during rapid extension, such as in baseball pitching, lags behind that seen during passive elbow motion. According to a new proposed theory of OCD lesion development, this lag should result in RC incongruency and elevated shear forces on the capitellum due to edge loading., Clinical Relevance: We propose a new biomechanical explanation for OCD of the capitellum in baseball pitchers: radial head lag. Understanding this process is the first step in efforts to prevent this common injury.

Background: Over-lengthening of the radial neck has been shown to affect ulnohumeral kinematics and has been proposed to affect radiocapitellar pressures. We hypothesized that an incremental increase in radial neck height increases the capitellar contact pressure and reduces the coronoid contact pressure. Knowledge of the effects of over-lengthening is clinically important in preventing pain and degenerative changes due to overstuffing., Methods: Six human cadaveric elbows were prepared on a custom-designed apparatus simulating muscle loads and passive flexion from 0° to 90° under gravity valgus torque while measuring joint contact pressures in this biomechanical study. Each elbow was tested sequentially starting with the intact specimen followed by insertion of a radial head prosthesis with 0, +2, and +4 mm of radial neck height, respectively., Results: Capitellar mean contact pressures significantly increased after insertion of +2 and +4 mm radial head prostheses (p < 0.03). The capitellar mean contact pressure with a 0 mm radial head prosthesis was 97 KPa. Insertion of +2 mm and +4 mm radial heads increased mean contact pressures to 391 KPa (p = 0.001) and 619 KPa (p = 0.001), respectively, with 90° of elbow flexion., Discussion: Increasing radial prosthesis height by 2 mm significantly increases capitellar contact pressures and reduces coronoid contact pressures., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: SOD and the Mayo Foundation receive royalties from commercial entities related to the subject of this article (Acumed). The remaining co-authors do not have any conflicts of interest to declare., (© 2019 The British Elbow & Shoulder Society.)

Purpose: To analyze the complications of arthroscopic heterotopic ossification (HO) excision and compare them with those of open removal of HO or a combined open-arthroscopic approach., Methods: We performed a retrospective review of elbow HO removal cases performed by a single surgeon from 1997 to 2014. In all cases studied, the intention was to restore range of motion owing to the presence of HO causing functional impairment. The arthroscopic, open, and combined treatment groups were compared., Results: The study cohort consisted of 223 surgical procedures performed on 213 elbows in 211 patients. Fifty major complications occurred in 46 cases (21%): 17 hematomas (8%) treated by irrigation and debridement, 8 cases of HO requiring reoperation (4%), 7 deep infections (3%), 4 contractures (2%), 3 cases of delayed-onset ulnar neuritis (1%), 2 cases of distal humeral avascular necrosis (1%), 2 tendon ruptures (1%), 2 cases of instability requiring reconstruction (1%), 2 postoperative fractures (1%), 1 intraoperative fracture (<0.5%), 1 case of worsening of pre-existing neuropathic pain (<0.5%), and 1 permanent partial posterior interosseous nerve injury (<0.5%). Of these 46 cases, the major complications occurred in 6 of the 41 (15%) performed arthroscopically, in 36 of the 158 (23%) performed open and in 4 of the 21 (17%) with combined (i.e. open + arthroscopic) HO removal. Preventive strategies, introduced to prevent hematomas and delayed-onset ulnar neuritis, reduced the rate of major complications from 35% during the period from 1997 to 2005 to 10% during the period from 2006 to 2014 (P < .0001). Moreover, the rate of reoperations was reduced from 34% to 10% in the same periods (P < .0001). Minor complications occurred in 36 cases (16%), including 17 cases of transient nerve palsy, 9 cases of superficial infection or delayed wound healing, 6 cases of mild instability, and 4 cases of hematoma resolved by aspiration., Conclusions: The use of arthroscopy-or a combination of arthroscopic and open techniques-to remove HO around the elbow by a surgeon skilled in both arthroscopic and open elbow surgery does not increase the risk of major complications or need for reoperation compared with traditional open surgery. Preventive strategies, such as avoiding raising skin flaps by using multiple separate incisions for open and prophylactic ulnar nerve decompression in arthroscopic cases, were developed during the study period. These strategies were monitored prospectively and found to be effective in preventing two-thirds of the major complications needing reoperation with both open and arthroscopic HO removal., Level of Evidence: Level III, retrospective comparative study of prospectively collected data., (Copyright © 2019 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Purpose: Various radial head prosthesis designs are currently in use. Few studies compare different prosthetic designs. We hypothesized that increasing a cementless implant stem's length would reduce stem-bone micromotion, with both short and long neck cuts. We also hypothesized that a minimum stem length might be required for the initial fixation strength of a press-fit implant., Methods: In 16 fresh-frozen cadaveric elbows (8 pairs), the radial head and neck were cut either 10 or 21 mm below the top of the head. Modular cementless stems were inserted and sequentially lengthened in 5-mm increments. Micromotion under eccentric loading was tested after each incremental change., Results: Incremental lengthening of the prosthetic stem and the amount of neck resection (10-mm cut vs 21-mm cut) both had a significant effect on micromotion. After a 10-mm radial head-neck resection, we observed a significant decrease in micromotion with stem lengths of 25 mm or greater, whereas with 21 mm of neck resection there was no further reduction in micromotion with increased stem length. These differences can be explained, at least in part, by the concept of the cantilever quotient: the ratio of the head-neck length outside the bone to the total length of the implant., Conclusions: The length of the stem affects the initial stability of press-fit radial head prostheses when the level of head and neck resection is at the minimum (ie, 10 mm) for currently available prosthetic designs. At this resection level, stems 25 mm or greater had significantly higher initial stability, but all stem lengths tested had mean micromotion values within the threshold for bone ingrowth., Clinical Relevance: The length of a radial head prosthetic stem affects the initial stability of press-fit radial head prostheses when the level of head and neck resection is at the minimum (ie, 10 mm) for currently available prosthetic designs., (Copyright © 2019 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Background: Heterotopic ossification (HO) is a well-recognized cause of limited flexion-extension, but it can also limit pronation-supination. There is a paucity of literature concerning restriction of pronation-supination due to HO., Methods: We conducted a retrospective review of patients who had undergone elbow surgery for HO removal between January 1, 2003, and September 27, 2013. Computed tomography scans were reviewed to determine the presence of HO restricting forearm rotation and were rated independently by 4 observers. Each elbow was given 1 of 4 scores according to the likelihood that HO was restricting forearm rotation. Agreement was achieved when 3 or 4 observers thought that HO definitely or probably caused a loss of pronation-supination., Results: Of 132 post-traumatic patients undergoing HO excision for restricted elbow motion, 61 (46%) also lacked a functional arc of pronation and supination (50° and 50°, respectively). Of these 61 patients, 32 (53%) were considered to have lost forearm rotation because of HO. The remaining 29 patients (47%) were thought to have restricted forearm rotation for reasons unrelated to HO., Discussion: In this study, loss of pronation-supination affected almost half of the patients (61 of 132 [46%]) undergoing HO excision around the elbow. Of these 61 patients, 32 (52%) had HO extending into the proximal forearm and affecting rotation. From our data, one can expect that about one-quarter (24% of patients in this study, or 32 of 132) with post-traumatic HO of the elbow will have a significant functional loss of pronation-supination due to HO extending into the forearm., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The interosseous membrane (IOM) and distal radioulnar joint (DRUJ) provide axial stability to the forearm. Our hypothesis was that injury to these structures alters force transmission through the elbow., Methods: A custom-designed apparatus that applies axial loads from the wrist to the elbow was used to test 10 cadaveric upper limbs under the following simulated conditions (1) intact, (2) DRUJ injury, (3) IOM injury, or (4) IOM + DRUJ injury. IOM injury was simulated by osteotomies of the IOM attachment to the radius, and DRUJ injury was simulated by distal ulnar oblique osteotomy. We applied 160 N of axial force during cyclic and functional range of forearm rotation (40 o pronation/40 o supination), and force, contact pressure, and contact area through the elbow joint were measured simultaneously., Results: The force across the radiocapitellar joint was significantly higher in the IOM + DRUJ injury and the IOM injury groups than in the intact and DRUJ injury groups. The mean force across the radiocapitellar joint was not significantly different between the intact and DRUJ injury groups or between the IOM + DRUJ injury and the IOM injury groups. Forces across the ulnohumeral joint showed an inverse pattern to those in the radiocapitellar joint., Conclusions: These findings suggest that injury to the IOM contributes more to the disruption of the normal distribution of axial loads across the elbow than injury to the DRUJ., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Purpose: A simple overlay device (SOD) was developed to measure radial head implant length. The purpose of this study was to determine the accuracy and reliability of this device for measuring experimental radial head implant length., Methods: Five fresh frozen cadavers were implanted with sequentially longer implants, adjusted by neck length (0, 2, 4, and 8 mm). Fluoroscopic images were obtained in 4 forearm positions: anteroposterior in supination in full extension, anteroposterior in pronation in full extension, supinated in 45° of flexion, and neutral in 45° of flexion. The SOD measurements (made by 2 observers) were compared with the native original radial head (control) to assess implant length. In addition, gapping of the ulnohumeral joint space was measured for comparison purposes., Results: The measured radial head and neck lengths for the specimens were 33, 39, 31, 34, and 42 mm. The difference between the actual radial head and neck lengths and those measured with the SOD template averaged less than 2 mm for all 4 collar sizes, except in 1 measurement in which the bicipital tuberosity could not be visualized. The median intraclass correlation coefficients for observer 1 compared with the SOD were 0.94 to 0.99. The median intraclass correlation coefficients between observers were 0.88 to 0.95. For both observers, elbow position, collar height, and the 2 variables combined did not significantly affect the SOD values. The other method that was evaluated, that of measurement of the ulnohumeral joint space, had higher interobserver variability versus the SOD, and allowed detection of lengthening of over 4 mm., Conclusions: The SOD is a reliable method for simply assessing radial head length with radiographs and can accurately detect 2 mm or more of proximal radial lengthening., Clinical Relevance: The SOD is a simple and accurate method that can help to optimize radial head sizing., (Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate the effect of intentional undersizing of prosthetic radial head implant diameters on joint contact pressures., Methods: Eight fresh-frozen cadaveric elbows were aligned in neutral extension and loaded with 100 N using a custom testing apparatus. Radiocapitellar contact pressures were recorded using a Tekscan thin-film pressure sensor. Prosthetic radial head replacement was performed with 2 prostheses: the Anatomic Radial Head and the Evolve Proline Radial Head prostheses. Each design was sized according to the manufacturer's recommendations and then again using 2-mm smaller radial heads., Results: Average and peak pressures were significantly higher with the Evolve than the Anatomic prostheses (P < 0.03 and 0.02, respectively). Peak pressures decreased from 4.2 ± 0.5 MPa to 2.9 ± 0.3 MPa for the Anatomic Radial Heads and from 5.6 ± 0.5 MPa to 3.9 ± 0.6 MPa when the Evolve Radial Heads were undersized by 2 mm. The mean pressures of the Anatomic Radial Heads (1.4 ± 0.1 MPa) did not change significantly with undersizing (1.3 ± 0.1 MPa, P = 0.12), whereas the mean pressures of the Evolve Radial Heads (1.6 ± 0.1 MPa) were significantly reduced with undersizing (1.4 ± 0.1 MPa, P < 0.02)., Conclusion: Both mean and peak pressures were initially high for the Evolve Radial Head sized based on the short axis diameter and were improved with further undersizing by 2 mm. Peak, but not mean, contact pressures were improved by undersizing the Anatomic prosthesis based on the long axis diameter., Clinical Relevance: These findings support the clinical recommendation of some surgeons to undersize the Evolve prosthesis by 2-mm smaller diameter than the current manufacturer's suggestion and give reason to consider doing the same for the Anatomic prosthesis.

Background: Long-term radiographic arthritis has been commonly reported after radial head excision. Concern over radial head arthroplasty may arise in certain situations including capitellar arthritis, radiocapitellar malalignment, and in young and active patients. We hypothesized that radial head excision increases coronoid contact pressures, which may at least be partially reduced by radiocapitellar Achilles tendon disc arthroplasty., Methods: Coronoid and capitellar contact pressure was measured on 6 human cadaveric elbows on a custom-designed gravity-valgus simulator under passive flexion from 0° to 90°. Sequential testing, starting with the intact specimen, resection of the radial head, and finally, radiocapitellar Achilles tendon disc arthroplasty were performed on each specimen., Results: Mean contact pressure of the coronoid significantly increased after radial head excision (P < .0001) and significantly improved after Achilles disc arthroplasty (P < .0001). The pressure difference was most pronounced on the lateral coronoid. From 15° to 85° of elbow flexion, mean contact pressures on the lateral coronoid were 291 kPa and 476 kPa before and after radial head excision, respectively (P < .0001). Achilles disc arthroplasty significantly lowered coronoid contact pressures to 385 kPa (P = .002); however, they remained significantly higher than those in the intact radial head group (P = .0009)., Conclusions: Radial head resection increases contact pressure in the coronoid, especially the lateral coronoid. This study showed that radiocapitellar Achilles disc arthroplasty significantly improves contact pressures on the coronoid after radial head resection. Achilles disc arthroplasty could be considered in patients who are not candidates for radial head arthroplasty., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Purpose: There is scant knowledge about the relationship between the size of the radial head and the size of the capitellum. Also, no data exist comparing the size of the capitellum between the left and the right elbow., Methods: Eight pairs of elbows and 12 single elbows from fresh-frozen cadavers were obtained for this study. The vertical height and anterior width of the capitellum were measured with digital calipers. Four different measurements were performed at the radial head: longest outer diameter, shortest outer diameter, the long dish diameter, and short dish diameter. The Pearson intrarater intraclass correlation coefficients were obtained for all measurements., Results: For the paired elbows, the correlations ranged between 0.95 and 0.96 for the capitellar dimensions and 0.77 and 0.98 for the radial head dimensions. The correlations between the long outer diameter of the radial head with the vertical height and the anterior width of the capitellum were 0.8 and 0.9, respectively., Conclusions: There is a high correlation between the long outer diameter of the radial head and the vertical height of the capitellum as well its anterior width. There is also a high correlation between the left and the right elbow., Clinical Relevance: These findings are relevant to radiocapitellar arthroplasty and may be useful for radiocapitellar prosthetic design as well as in the preoperative planning of cases in which the radial head and/or the capitellum is destroyed., (Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Aims: The aim of this study was to evaluate two hypotheses. First, that disruption of posterior bundle of the medial collateral ligament (PMCL) has to occur for the elbow to subluxate in cases of posteromedial rotatory instability (PMRI) and second, that ulnohumeral contact pressures increase after disruption of the PMCL., Materials and Methods: Six human cadaveric elbows were prepared on a custom-designed apparatus which allowed muscle loading and passive elbow motion under gravitational varus. Joint contact pressures were measured sequentially in the intact elbow (INTACT), followed by an anteromedial subtype two coronoid fracture (COR), a lateral collateral ligament (LCL) tear (COR + LCL), and a PMCL tear (COR + LCL + PMCL)., Results: There was no subluxation or joint incongruity in the INTACT, COR, and COR + LCL specimens. All specimens in the COR + LCL + PMCL group subluxated under gravity-varus loads. The mean articular contact pressure of the COR + LCL group was significantly higher than those in the INTACT and the COR groups. The mean articular contact pressure of the COR + LCL + PMCL group was significantly higher than that of the INTACT group, but not higher than that of the COR + LCL group., Conclusion: In the presence of an anteromedial fracture and disruption of the LCL, the posterior bundle of the MCL has to be disrupted for gross subluxation of the elbow to occur. However, elevated joint contact pressures are seen after an anteromedial fracture and LCL disruption even in the absence of such subluxation. Cite this article: Bone Joint J 2018;100-B:1060-5.

Background: Joint incongruity in posteromedial rotatory instability (PMRI) has been theorized to determine early articular degenerative changes. Our hypothesis was that the articular contact area and contact pressure differ significantly between an intact elbow and an elbow affected by PMRI., Methods: Seven cadaveric elbows were tested under gravity varus stress using a custom-made machine designed to simulate muscle loads and allow passive elbow flexion (0° to 90°). The mean contact area and contact pressure data were collected and processed using the Tekscan sensor and software. After testing the intact specimen (intact elbow), a PMRI injury was simulated (PMRI elbow) and the specimen was tested again., Results: The PMRI elbows were characterized by initial joint subluxation and significantly elevated articular contact pressure. Both worsened, corresponding with a reduction in contact area, as the elbow was flexed from 0° until the joint subluxation and incongruity spontaneously reduced (at a mean [and standard error] of 60° ± 5° of flexion), at which point the mean contact pressure decreased from 870 ± 50 kPa (pre-reduction) to 440 ± 40 kPa (post-reduction) (p < 0.001) and the mean contact area increased from 80 ± 8 mm to 150 ± 58 mm (p < 0.001). This reduction of the subluxation was also followed by a shift of the contact area from the coronoid fracture edge toward the lower portion of the coronoid. At the flexion angle at which the PMRI elbows reduced, both the contact area and the contact pressure of the intact elbows differed significantly from those of the PMRI elbows, both before and after the elbow reduction (p < 0.001)., Conclusions: The reduction in contact area and increased contact pressures due to joint subluxation and incongruity could explain the progressive arthritis seen in some elbows affected by PMRI., Clinical Relevance: This biomechanical study suggests that the early degenerative changes associated with PMRI reported in the literature could be subsequent to joint incongruity and an increase in contact pressure between the coronoid fracture surface and the trochlea.

Background: Minimal micromotion is necessary for osteointegration of cementless radial head prostheses. When radial head fractures extend longitudinally, where the neck cut for prosthetic replacement should be made is uncertain. We hypothesized that complete resection of the notched portion of a radial neck confers no advantage in initial stability compared with not resecting the defect and inserting the implant into a notched radial neck., Materials and Methods: The radii of 7 cadavers underwent radial head resection and implantation with a 25-mm-long press-fit radial head stem. Before implantation, a 5-mm-long notch that was less than 1-mm wide was made in the radial neck. After the stem-bone micromotion was recorded, the proximal 5 mm of radial neck, incorporating the entire notch, was cut away, the stem was inserted 5 mm further, and the resulting micromotion was recorded., Results: The mean micromotion measured in the presence of a cortical notch was 51 ± 6 µm. After the neck was circumferentially cut and the stem was advanced, the micromotion (46 ± 9 µm) was not statistically significantly different., Discussion: Initial stability of an adequately sized cementless stem in the presence of a 5-mm-long cortical notch was well within the threshold needed for bone ingrowth (<100 µm). In addition, there was no reduction of micromotion after the notch-containing portion of the radial neck was resected and the stem was advanced. Making a neck cut distal to a 5-mm-long, 1-mm-wide cortical notch does not confer added stability. Thus, surgeons can preserve bone stock and avoid an aggressive neck cut., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Forearm rotation is closely associated with the axiorotational force transmission through the elbow joint. A technique has been developed to study the transmission of force across the radiocapitellar and ulnotrochlear joints during forearm rotation., Methods: Ten human cadaveric upper limbs were prepared on a custom-designed apparatus that permits the application of extrinsic axial loads across an intact cadaveric elbow joint. A force-sensitive transducer was inserted into the elbow joint of each cadaver. A 160 N axial force was applied to the specimen during cyclic forearm rotation while the force, contact pressure, and contact area through the elbow joint were measured., Results: The mean force across the radiocapitellar joint showed no significant difference between pronation and supination (P = .3547). The radiocapitellar joint showed significantly higher contact area (P = .0001) and lower contact pressure (P = .0001) in pronation than in supination. The mean values for contact pressure, area, and force across the ulnotrochlear joint were not significantly different between supination and pronation., Conclusion: The contact pressure and contact area of the radiocapitellar joint in the cadaveric model changed according to forearm rotation while the force remained constant. The mean contact pressure of the radiocapitellar joint in pronation was significantly lower than that in supination because the force across it did not change significantly and its contact area decreased significantly. These findings may suggest that the pronated elbow can play an important role in protecting the radiocapitellar joint in high-impact activities like delivering punch in martial arts or falling on an outstretched arm., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Objective: To determine whether the Summary Outcome Determination (SOD) score had exhibited a high level of physician-patient agreement in surgical patients., Patients and Methods: The medical records of 320 postoperative patients were reviewed, of whom 164 patients were included in the study. Patients were included if both physician-assigned and patient-assigned SOD scores had been recorded. The SOD is administered as follows: the patient is asked "Compared to before surgery, is your elbow/shoulder better, worse or no different?" If better: "Is it improved, greatly improved, almost normal or normal?" If worse: "Is it worse or profoundly worse, or as bad as dying?" Each category is associated with a numerical value and definition for further clarification. The patient is asked to assign a category and a numerical value after the physician has already done so. These categories and values were evaluated between raters (ie, physician and patient) to assess reliability., Results: The intraclass correlation coefficient of physician-patient numerical ratings was "excellent" (0.93). The Bland-Altman 95% limits of agreement on the differences between the physician and the patient ranged from -1.3 to 1.3. The physician and patient numerical rankings matched exactly in 118 patients (72%) or differed by a factor of no more than 1 (26%) in 161 (98%) patients., Conclusion: The SOD score can be used as both a surgeon-based and a patient-based outcome score, given the high level of agreement. Given its brevity, ease of understanding, and high interrater reliability, the SOD has the potential to be used across multiple specialties to rate outcomes., (Copyright © 2017 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.)

Hypothesis: The purposes of this study were to test the hypothesis that coronoid deficiency in the setting of posteromedial rotatory instability (PMRI) must be reconstructed to restore articular contact pressures to normal and to compare 3 different osteochondral grafts for this purpose., Methods: After creation of a anteromedial fracture, six cadaveric elbows were tested under gravity varus stress using a custom-made machine designed to simulate muscle loads and to passively flex the elbow. Mean articular surface contact pressure data were collected and processed using TekScan sensors and software. After testing of the intact specimen (intact condition), a PMRI injury was created (PMRI condition). Testing was repeated after reconstruction of the lateral collateral ligament (LCL) (LCL-only condition), followed by reconstruction of the coronoid with 3 different osteochondral graft techniques (reconstructed conditions)., Results: Contact pressure was consistently significantly higher in the PMRI elbow compared with the intact, LCL-only, and reconstructed conditions (P < .006). The LCL-only elbow contact pressure was significantly higher than that of the intact and reconstructed conditions from 5° to 55° of flexion (P = .018). The contact pressure of the intact elbow was never significantly different from that of the reconstructed elbow, except at 5° of flexion (P ≤ .008). No significant difference was detected between each of the reconstructed techniques (P ≥ .15). However, the annular surface of the radial head was the only graft that yielded contact pressures not significantly different from normal at any flexion angle., Conclusion: Isolated reconstruction of the LCL did not restore native articular surface contact pressure, and reconstruction of the coronoid using osteochondral graft was necessary. There was no difference in contact pressures among the 3 coronoid reconstruction techniques., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Posteromedial rotatory instability (PMRI) of the elbow consists of an anteromedial coronoid fracture with lateral collateral ligament (LCL) and posterior bundle of the medial collateral ligament (PMCL) tears. We hypothesized that the LCL tear is required for elbow subluxation/joint incongruity and that an elbow affected by an anteromedial subtype 2 coronoid fracture and a PMCL tear exhibits contact pressures different from both an intact elbow and an elbow affected by PMRI., Materials and Methods: Six cadaveric elbows were tested under gravity varus stress using a custom-made machine designed to simulate muscle loads and to passively flex the elbow from 0° to 90° and measure joint contact pressures. After testing of the intact specimen (INTACT-elbow), an anteromedial subtype 2 coronoid fracture with a PMCL tear (COR+PMCL-elbow) and a PMRI injury (PMRI-elbow), after adding an LCL tear, were tested. The highest values of mean contact pressure were used for the comparison among the 3 groups., Results: Neither subluxation nor joint incongruity was observed in the COR+PMCL-elbow. The addition of an LCL detachment consistently caused subluxation and joint incongruity. Mean contact pressures were higher in the COR+PMCL-elbow compared with the INTACT-elbow (P < .03) but lower than in the PMRI-elbow (P < .001)., Conclusions: The LCL lesion in PMRI is necessary for elbow subluxation and causes marked elevations in contact pressures. Even without subluxation, the COR+PMCL-elbow showed higher contact pressures compared with the INTACT-elbow. Treatment of PMRI should be directed toward prevention of joint incongruity, whether by surgical or nonsurgical means, to prevent high articular contact pressures., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Metallic radial head prostheses are often used in the management of comminuted radial head fractures and elbow instability. We hypothesized that during radiocapitellar subluxation, the contact pressure characteristics of an anatomic radial head prosthesis will more closely mimic those of the native radial head compared with a monopolar circular or a bipolar circular radial head design., Materials and Methods: With use of 6 fresh frozen cadaver elbows, mean radiocapitellar contact pressures, contact areas, and peak pressures of the native radial head were assessed at 0, 2, 4, and 6 mm of posterior subluxation. These assessments were repeated after the native radial head was replaced with anatomic, monopolar circular and bipolar circular prostheses., Results: The joint contact pressures increased with the native and the prosthetic radial head subluxation. The mean contact pressures for the native radial head and anatomic prosthesis increased progressively and significantly from 0 to 6 mm of subluxation (native, 0.6 ± 0.0 MPa to 1.9 ± 0.2 MPa; anatomic, 0.7 ± 0.0 MPa to 2.1 ± 0.3 MPa; P < .0001). The contact pressures with the monopolar and bipolar prostheses were significantly higher at baseline and did not change significantly further with subluxation (monopolar, 2.0 ± 0.1 MPa to 2.2 ± 0.2 MPa [P = .31]; bipolar, 1.7 ± 0.1 MPa to 1.9 ± 0.1 MPa [P = .12]). The pattern of increase in contact pressures with the anatomic prosthesis mimicked that of the native radial head. Conversely, the circular prostheses started out with higher contact pressures that stayed elevated., Conclusion: The articular surface design of a radial head prosthesis is an important determinant of joint contact pressures., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Objectives: We sought to determine if a durable bilayer implant composed of trabecular metal with autologous periosteum on top would be suitable to reconstitute large osteochondral defects. This design would allow for secure implant fixation, subsequent integration and remodeling., Materials and Methods: Adult sheep were randomly assigned to one of three groups (n = 8/group): 1. trabecular metal/periosteal graft (TMPG), 2. trabecular metal (TM), 3. empty defect (ED). Cartilage and bone healing were assessed macroscopically, biochemically (type II collagen, sulfated glycosaminoglycan (sGAG) and double-stranded DNA (dsDNA) content) and histologically., Results: At 16 weeks post-operatively, histological scores amongst treatment groups were not statistically different (TMPG: overall 12.7, cartilage 8.6, bone 4.1; TM: overall 14.2, cartilage 9.5, bone 4.9; ED: overall 13.6, cartilage 9.1, bone 4.5). Metal scaffolds were incorporated into the surrounding bone, both in TM and TMPG. The sGAG yield was lower in the neo-cartilage regions compared with the articular cartilage (AC) controls (TMPG 20.8/AC 39.5, TM 25.6/AC 33.3, ED 32.2/AC 40.2 µg sGAG/1 mg respectively), with statistical significance being achieved for the TMPG group (p < 0.05). Hypercellularity of the neo-cartilage was found in TM and ED, as the dsDNA content was significantly higher (p < 0.05) compared with contralateral AC controls (TM 126.7/AC 71.1, ED 99.3/AC 62.8 ng dsDNA/1 mg). The highest type II collagen content was found in neo-cartilage after TM compared with TMPG and ED (TM 60%/TMPG 40%/ED 39%). Inter-treatment differences were not significant., Conclusions: TM is a highly suitable material for the reconstitution of osseous defects. TM enables excellent bony ingrowth and fast integration. However, combined with autologous periosteum, such a biocomposite failed to promote satisfactory neo-cartilage formation.Cite this article: E. H. Mrosek, H-W. Chung, J. S. Fitzsimmons, S. W. O'Driscoll, G. G. Reinholz, J. C. Schagemann. Porous tantalum biocomposites for osteochondral defect repair: A follow-up study in a sheep model. Bone Joint J 2016;5:403-411. DOI: 10.1302/2046-3758.59.BJR-2016-0070.R1., Competing Interests: ICMJE conflict of interest: S. W. O’Driscoll and the Mayo Foundation receive royalties from Acumed, LLC; Tornier, Inc.; and Aircast, Inc. The Mayo Foundation receives royalties from Zimmer, Inc. All other authors have no conflicts of interest to report., (© 2016 Mayo Foundation for Education and Research.)

Purpose: To determine the effect of capitellar impaction fractures on radiocapitellar stability in a model that simulated a terrible triad injury., Methods: Six cadaveric elbows were dissected free of skin and muscles. Tendons were preserved. The lateral collateral ligament was released and repaired (surgical control). Two sizes of capitellar impaction defects were created. After lateral collateral ligament release and repair, we then sequentially created osseous components of a terrible triad injury (partial radial head resection and coronoid fracture) through an olecranon osteotomy that was fixed with a plate. Radiocapitellar stability was recorded after the creation of each new condition., Results: Significantly less force was required for radiocapitellar subluxation after the creation of 20° and 40° capitellar defects compared with the surgical control (intact capitellum). After the addition of a Mason type II radial head defect and then a coronoid defect, stability decreased significantly further., Conclusions: Impaction fractures of the distal portion of the capitellum may contribute to a loss of radiocapitellar stability, particularly in an elbow fracture-dislocation., Clinical Relevance: Because these injuries may be unrecognized, consideration should be given to diagnosing and addressing them., (Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine if radiocapitellar contact pressures would be elevated with nonanatomical (circular) prostheses over those mimicking native anatomy and if such pressures would be related to the depth and contour of the articular dish and to the pattern of prosthetic articulation against the lateral trochlear ridge., Methods: Three commercially available circular radial head designs were compared with an anatomical radial head and 2 modified anatomical prototype radial head designs in 10 cadaveric specimens. Each prosthesis and specimen combination was loaded in neutral rotation and maximal extension with a custom testing apparatus while measuring contact areas and pressures using thin-film pressure sensors., Results: Anatomical radial head prototype 2 had similar radiocapitellar contact areas and mean pressures as the native radial head; all other designs showed significant decreases in contact area and increased mean pressures. Peak contact pressures were also measured and were significantly elevated with all prostheses tested. Anatomical designs are statistically more likely to mimic normal contact with the lateral trochlear ridge and its adjacent sulcus than circular prostheses. They are also significantly less likely to have contact pressures above the 5 MPa threshold that is thought to be harmful to cartilage. The depth of the articular dish had a significant effect on contact area and pressure., Conclusions: Commercially available radial head prostheses demonstrated reduced radiocapitellar contact areas and elevated contact pressures during compressive loading. These were significantly greater with symmetrical circular prostheses than with asymmetrical elliptical designs. The prosthesis that best mimicked native contact behavior was the anatomical radial head prototype 2 owing to its design for articulating with the capitellum, the lateral trochlear ridge, and the sulcus between., Clinical Relevance: Because radial head prostheses have the potential to cause capitellar erosion or arthritic change, those with lower contact pressures may lead to fewer such complications., (Copyright © 2015 American Society for Surgery of the Hand. All rights reserved.)

Hypothesis: Our aim was to test whether anatomically designed metallic radial head implants could better reproduce native radiocapitellar contact pressure and areas than nonanatomic implants., Methods: The distal humerus and proximal radius from 6 cadaveric upper extremities were serially tested in supination with 100 N of compression force at 4 angles of flexion (0°, 30°, 60°, and 90°). By use of a thin flexible pressure transducer, contact pressures and areas were measured for the native radial head, an anatomic implant, a nonanatomic circular monopolar implant, and a bipolar nonanatomic implant. The data (mean contact pressure and mean contact area) were modeled using a 2-factor repeated-measures analysis of variance with P ≤ .05 considered to be significant., Results: The mean contact areas for the prosthetic radial heads were significantly less than those seen with the intact radial heads at every angle tested (P < .01). The mean contact pressures increased significantly with all prosthetic radial head types as compared with the native head. The mean contact pressures increased by 29% with the anatomic prosthesis, 230% with the monopolar prosthesis, and 220% with the bipolar prosthesis. Peak pressures of more than 5 MPa were more commonly observed with both the monopolar and bipolar prostheses than with the anatomic or native radial heads., Conclusions: The geometry of radial head implants strongly influences their contact characteristics. In a direct radius-to-capitellum axial loading experiment, an anatomically designed radial head prosthesis had lower and more evenly distributed contact pressures than the nonanatomic implants that were tested., (Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: While many design-specific features of radial head prostheses have been studied (ie, geometry and surface coating), the optimum technique for canal preparation has not been determined. We hypothesized that preparation of the radial canal with a reamer would allow for the accommodation of a larger stem diameter versus following canal preparation with a rasp, and would provide acceptable stem-bone micromotion., Methods: Paired proximal radii from 7 cadavers were prepared by a rasp on one side and a reamer on the contralateral side. Cementless radial head stems of increasing diameter were sequentially implanted up to the maximum size or until a fracture occurred and the micromotion between the stem and bone was recorded., Results: In 3 of 5 pairs, at least a 1 mm larger stem size fit into the canal after reaming versus after rasping (P = .04). 5 of 7 radii fractured secondary to intentional stem oversizing. For the optimally-sized stems, similar micromotion values were observed whether the canal was rasped (41 ± 6 μm) or reamed (44 ± 6 μm) (P = .72)., Discussion: This study investigated an aspect of radial head arthroplasty technique about which little has currently been published. It is possible that use of a reamer rather than a rasp, while providing similar initial stability, might expand the stem size options for initial press-fit stability, and decrease the risk of fracture., Conclusion: Radial canal preparation with a reamer allows for implantation of a 1 mm larger stem diameter versus rasping, while providing comparable initial stability to that achieved after rasping., (Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: A major factor limiting the use of elbow arthroscopy for contracture release is concern regarding nerve injury. The purpose of this report is to document the risk of nerve injury in a large series of arthroscopic contracture releases utilizing a safety-driven strategy., Methods: A series of 502 arthroscopic elbow contracture releases (including 388 osteocapsular arthroplasties) performed in 464 patients by one surgeon was reviewed retrospectively. The safety-driven step-wise strategy had been carried out in a standardized sequence: (1) Get In and Establish a View, (2) Create a Space in Which to Work, (3) Bone Removal, and (4) Capsulectomy. Neurologic complications were assessed and were followed until resolution., Results: No patient had a permanent nerve injury. Twenty-four patients (5%) had a transient nerve injury, associated with prolonged tourniquet time, cutaneous dysesthesia attributed to open incisions, simultaneous ulnar nerve transposition, or retractor use. All nerve deficits resolved after one day to twenty-four months, with one patient lost to follow-up., Conclusions: Utilizing the technique described, arthroscopic contracture release and debridement of the elbow was performed with a low risk of nerve injury., Level of Evidence: Therapeutic level III. See instructions for authors for a complete description of levels of evidence.

Background: Osteointegration of press-fit radial head implants is achieved by limiting micromotion between the stem and bone. Aspects of stem design that contribute to the enhancement of initial stability (ie, stem diameter and surface coating) have been investigated. The importance of total prosthesis length and level of the neck cut has not been examined., Methods: Cadaveric radii were implanted with cementless, porous-coated radial head stems. We resected 10, 12, 15, 20, and 25 mm of radial neck in each specimen. Stem-bone micromotion was measured after each cut. Values were expressed in terms of quotients (cantilever quotient)., Results: A threshold effect was observed at 15 mm of neck resection (cantilever quotient, 0.4), with a significant increase in micromotion observed between 12 mm (40 ± 10 μm) and 15 mm (80 ± 25 μm). A cantilever quotient of 0.35 or less predicted implant stability, whereas implants with a cantilever quotient of 0.6 or more were unstable. In between, the stems were "at risk" of instability., Conclusion: Initial stem stability of a porous-coated, cementless radial head implant is dependent on length of the implant stem within bone and the level of the cut (amount of bone resected). Stability may be compromised by an implant with a combined head and neck length that is too long compared with the stem length within the canal. We found a critical ratio of exposed prosthesis to total implant length (cantilever quotient of 0.4), which puts the prosthesis at risk of inadequate initial stability. These data carry important implications for implant design and use., (Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Purpose: Stress shielding is known to occur around rigidly fixed implants. We hypothesized that stress shielding around radial head prostheses is common but nonprogressive. In this study, we present a classification scheme to support our radiographic observations., Methods: We reviewed charts and radiographs of 86 cases from 79 patients with radial head implants from both primary and revision surgeries between 1999 and 2009. Exclusion criteria included infection, loosening, or follow-up of less than 12 months. We classified stress shielding as: I, cortical thinning; II, partially (IIa) or circumferentially (IIb) exposed stem; and III, impending mechanical failure., Results: Of 26 well-fixed stems, 17 (63%) demonstrated stress shielding: I = 2, II = 15 (IIa = 12, IIb = 3), and III = 0. We saw stress shielding with all stem types: cemented or noncemented; long or short; and straight, curved, or tapered. The only significant difference was that stems implanted into the radial shaft had less stress shielding than stems implanted into the neck or tuberosity (P = .03). The average follow-up was 33 months (range, 13-70 mo). Stress shielding was detectable by an average of 11 months (range, 1-15 mo). The pattern of bone loss was similar in 16 of 17 cases (94%), starting on the outer periosteal cortex. The 3 cases with circumferential exposure of the stem (stage IIb) averaged 2.6 mm (range, 1-4 mm) of exposed stem. Stress shielding never extended to the bicipital tuberosity, and there were no cases of impending mechanical failure., Conclusions: Stress shielding around radial head prostheses is common, regardless of stem design. However, it is typically minor, nonprogressive, and of questionable clinical consequence., Type of Study/level of Evidence: Therapeutic IV., (Copyright © 2012 American Society for Surgery of the Hand. All rights reserved.)

Background: Radial head prosthetic stems designed for bone ingrowth are available with both plasma spray and grit blasted surfaces. A recent study comparing micromotion between the 2 demonstrated greater micromotion in the plasma spray than grit blasted stems, even though the latter had lower surface roughness. This raised the question that perhaps the size mismatch for grit-blasted radial head stems (0.5 mm) might be inadequate for plasma spray stems., Hypothesis: A tighter initial press-fit with plasma spray radial head stems may be gained by preparation with an undersized rasp., Methods: Paired cadaveric radii were implanted with plasma spray stems. The surgical control was prepared with a rasp designated for its corresponding stem size ("size-matched"), while the experimental group was prepared with a rasp 0.5 mm smaller than designated ("undersized")., Results: The micromotion for the undersized rasp group (46 ± 12 μm) was not significantly different than for the size-matched rasp group (21 ± 12 μm) (P = .1)., Discussion: Contrary to our hypothesis, no reduction in micromotion was observed when using an undersized rasp with a plasma spray stem. The micromotion results were not different from those observed when using a size-matched rasp, and actually approached significance in the opposite direction. This may be due to the rough stem surface chipping away bone fragments, rather than the bone being cut away precisely as is done with a rasp., Conclusion: The use of an undersized rasp prior to implantation of a plasma spray radial head prosthesis does not confer any added benefit in terms of initial stability., (Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: Successful bone ingrowth around cementless implants requires adequate initial stability. Hoop stress fractures during stem insertion can potentially hinder prosthesis stability., Hypothesis: We hypothesized that an oversized radial head prosthetic stem (1 mm "too large" and causing a hoop stress fracture during insertion) would result in an unacceptable amount of micromotion., Materials and Methods: Grit-blasted radial head prosthetic stems were implanted into cadaveric radii. Rasp and stem insertion energies were measured, along with micromotion at the stem tip. The sizes were increased until a fracture developed in the radial neck., Results: Prosthetic radial head stems that were oversized by 1 mm caused small cracks in the radial neck. Micromotion of oversized stems (42 ± 7 μm) was within the threshold conducive for bone ingrowth (<100 μm) and not significantly different from that for the maximum sized stems (50 ± 12 μm) (P ≥ .4)., Discussion: Contrary to our hypothesis, hoop stress fractures caused by implantation of a stem oversized by 1 mm did not result in loss of stability. Stem micromotion remained within the range for bone ingrowth and was not significantly diminished after the fracture. This suggests that if a crack occurs during the final stages of stem insertion, it may be acceptable to leave the stem in place without adding a cerclage wire., Conclusion: A small radial neck fracture occurring during insertion of a radial head prosthetic stem oversized by 1 mm does not necessarily compromise initial stability., (Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Purpose: To test the hypothesis that visual estimation by a trained observer is as accurate and reliable as clinical goniometry for measuring elbow range of motion., Methods: Instrument validity and inter-observer reliability of visual estimation was evaluated on a consecutive series of 50 elbow contractures. Four observers with different levels of elbow experience first estimated extension and flexion of the contracted elbows and then measured them with a blinded goniometer., Results: Instrument validity for visually-based goniometry was extremely high. ICC scores were 0.97 for both extension and flexion estimations. Systematic error was negligible (1°) with upper limits of agreement being 9° (95% CI: 7°-11°) and 8° (95% CI: 6°-10°), respectively, for extension and flexion. For the expert surgeon, 92% of the visual estimates were within 5° of the value obtained by clinical goniometry. Between experienced observers (elbow surgeon and physician assistant), the ICC's were very high-0.96 for extension and 0.93 for flexion. The systematic errors were low, from -1° to 1° with upper limit of agreement being 11° (95% CI: 8°-14°). However, agreement was poor between an inexperienced study coordinator and the others (ICC's: 0.51-0.38, systematic errors: 8°-18°, upper limit of agreement: 32°-40°). The accuracy of the visual estimations made by the experienced elbow surgeon was as good as the measurements taken with a goniometer by the physician assistant or the clinical fellow and better than those taken by an inexperienced study coordinator., Conclusions: The trained human eye is highly capable of accurately estimating the range of motion of the elbow, compared to conventional clinical goniometry, depending on the experience of the observer., Level of Evidence: Diagnostic study, Level II.

Background: Management for Mason type II radial head fractures is controversial. We hypothesized that angulation or depression of a marginal radial head fragment would affect radiocapitellar stability similarly to fragment excision., Materials and Methods: A Mason type II radial head fracture was created in 6 cadaveric elbows by excising a segment from the anterolateral quadrant that was 30% of the diameter of the articular surface. Radiocapitellar stability was recorded under 5 sets of conditions: (1) intact radial head (intact), (2) 30% surface area fragment resected (partially excised), (3) anatomic fragment fixation with screws (fixed), (4) fragment fixation with 2 mm of depression relative to the articular surface (depressed), and (5) fragment fixation after a 30° wedge resection (angulated)., Results: The forces required to subluxate the joint were greatly reduced after fragment excision (5 ± 1 N; P = .0001) and restored to normal (21 ± 1 N; P = .9) after anatomic fixation of the excised fragment. The peak forces were significantly reduced with fragment depression (4 ± 1 N) and angulation (4 ± 2 N; P = .0001)., Conclusion: A radial head fracture that is depressed 2 mm or angulated 30° may cause up to an 80% loss of concavity-compression stability of the radiocapitellar joint., (Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: A critical component of evaluating the outcomes after surgery to restore lost elbow motion is the range of motion (ROM) of the elbow. This study examined if digital photography-based goniometry is as accurate and reliable as clinical goniometry for measuring elbow ROM., Materials and Methods: Instrument validity and reliability for photography-based goniometry were evaluated for a consecutive series of 50 elbow contractures by 4 observers with different levels of elbow experience. Goniometric ROM measurements were taken with the elbows in full extension and full flexion directly in the clinic (once) and from digital photographs (twice in a blinded random manner)., Results: Instrument validity for photography-based goniometry was extremely high (intraclass correlation coefficient: extension = 0.98, flexion = 0.96). For extension and flexion measurements by the expert surgeon, systematic error was negligible (0° and 1°, respectively). Limits of agreement were 7° (95% confidence interval [CI], 5° to 9°) and -7° (95% CI, -5° to -9°) for extension and 8° (95% CI, 6° to 10°) and -7° (95% CI, -5° to -9°) for flexion. Interobserver reliability for photography-based goniometry was better than that for clinical goniometry. The least experienced observer's photographic goniometry measurements were closer to the reference measurements than the clinical goniometry measurements., Conclusions: Photography-based goniometry is accurate and reliable for measuring elbow ROM. The photography-based method relied less on observer expertise than clinical goniometry. This validates an objective measure of patient outcome without requiring doctor-patient contact at a tertiary care center, where most contracture surgeries are done., (Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: Radial head prostheses are available with multiple geometric properties. The effect of design features on radiocapitellar stability has not been investigated., Hypothesis: The shape (depth and radius of curvature) of the articulating dish of a radial head prosthesis affects radiocapitellar stability., Materials and Methods: Radiocapitellar stability due to concavity-compression was evaluated in 8 fresh frozen elbows before and after radial head replacement with 2 different designs of radial head implants (RH 1 and RH 2). Both functioned as monopolar implants. Peak forces resisting subluxation and force-displacement characteristics were compared between the 2 and to the native radial head., Results: Radial head design significantly affected radiocapitellar stability. RH 1, which had a deeper dish than RH 2, required significantly higher peak forces to subluxate the radiocapitellar joint. The peak subluxation forces and the slopes of the force-displacement curves were not significantly different from the native radial head for RH 1, but they were for RH 2., Conclusion: The shape of the articular dish (depth, radius of curvature) of a monopolar radial head implant affects its contribution to radiocapitellar stability. An implant that mimics normal anatomy is more effective than a shallow radial head implant with a radius of curvature that is longer than normal., (Copyright © 2011 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: Initial stability of a textured surface prosthetic stem is necessary for bone in-growth. Surfaces currently used for radial head prostheses include titanium plasma spray and grit-blasted titanium., Hypothesis: Plasma spray radial head prosthetic stems are less dependent than grit-blasted stems on a tight press fit. Good initial press-fit stability, with acceptable micro-motion, can be achieved with a greater range of stem sizes using a plasma spray than grit-blasted surface., Methods: Paired cadaveric radii were implanted with plasma spray or grit-blasted radial head prosthetic stems. Micromotion at the stem tip was measured under circumstances simulating eccentric loads., Results: Micromotion in the plasma spray (PS) stems (49 ± 37) μm was not better than that in the grit-blasted (GB) stems (28 ± 10) μm (P = .13). Micromotion of less than 100 μm was measured in all 12 GB stems that were maximum or 1 mm less than maximum size, versus 5/6, and 4/6 PS stems, respectively., Discussion: Micromotion in plasma spray prosthetic radial head stems was not better than that seen in grit-blasted stems, contrary to our initial hypothesis., Conclusion: Grit-blasted prosthetic radial head stems confer initial press-fit stability that is as good as, or slightly better than, corresponding plasma spray stems. Acceptable amounts of micromotion can be achieved with 2 grit-blasted stem sizes and probably with 2 plasma spray stem sizes., (Copyright © 2011 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Introduction: Radiocapitellar stability depends, in part, on concavity-compression mechanics. This study was conducted to examine the effects of the soft tissues on radiocapitellar stability with radial head prostheses., Hypothesis: Monopolar radial head implants are more effective in stabilizing the radiocapitellar joint than bipolar radial head prostheses, with the soft tissues intact or repaired., Materials and Methods: Twelve fresh frozen elbow specimens were used to evaluate radiocapitellar stability with monopolar and bipolar radial heads. The study variables focused on varying soft tissue conditions and examined the mean peak subluxation forces put forth by each prosthesis design., Results: With the soft tissues intact, the mean peak force resisting posterior subluxation depended significantly on the radial head used (P = .03). Peak force was greatest for the native radial head (32 ± 7 N) and least with the bipolar prosthesis (12 ± 3 N), with the monopolar prosthesis falling in between (21 ± 4 N). The presence of soft tissues significantly affected the bipolar implant's ability to resist subluxation, though it did not significantly impact the native or monopolar radial heads., Discussion: This study reveals the dependence of radiocapitellar stability on soft tissue integrity, particularly for bipolar prostheses. Overall, monopolar prostheses have a better capacity to resist radiocapitellar subluxation., Conclusion: From a biomechanical perspective, the enhancement of elbow stability with a monopolar radial head prosthesis is superior to that with a bipolar design. This is especially true when the integrity of the soft tissues has been compromised, such as in trauma., (Copyright © 2011 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)