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Platelet-rich plasma (PRP) is a revolutionary treatment that harnesses the regenerative power of the body's own platelets to promote healing and tissue regeneration. While PRP therapy has emerged as a promising option for augmenting biologic healing in the shoulder, the complexity of shoulder disorders makes it difficult to draw definitive conclusions about the efficacy of PRP across different conditions and stages of disease. Our comprehensive review of twenty-four studies highlights the current state of PRP therapy in shoulder pathologies, revealing a wide variety of number of patients, control groups and results. Despite these challenges, the regenerative potential of PRP therapy is moderate in some conditions, with numerous studies demonstrating the positive effects. In conclusion, the authors of this study recommend the use of PRP therapy for adhesive capsulitis and rotator cuff repair of medium to large tears. However, they do not recommend the use of PRP for subacromial impingement or rotator cuff tears. It is up to the clinician's discretion to decide whether PRP therapy is appropriate for individual cases. However, there is still insufficient evidence to support the inclusion of PRP therapy in treatment protocols for other shoulder disorders. Therefore, further research is needed to fully explore the potential of PRP therapy in the treatment of various shoulder conditions.

PURPOSE: To (1) report the long-term outcomes associated with both operative and nonoperative management of capitellar osteochondritis dissecans (OCD), (2) identify factors associated with failure of nonoperative management, and (3) determine whether delay in surgery affects final outcomes. METHODS: All patients who received a diagnosis of capitellar OCD from 1995-2020 within a geographic cohort were included. Medical records, imaging studies, and operative reports were manually reviewed to record demographic data, treatment strategies, and outcomes. The cohort was divided into 3 groups: (1) nonoperative management, (2) early surgery, and (3) delayed surgery. Delayed surgery (surgery ≥6 months after symptom onset) was considered failure of nonoperative management. RESULTS: Fifty elbows with a mean follow-up period of 10.5 years (median, 10.3 years; range, 1-25 years) were studied. Of these, 7 (14%) were definitively treated nonoperatively, 16 (32%) underwent delayed surgery after at least 6 months of failed nonoperative treatment, and 27 (54%) underwent early surgical intervention. When compared with nonoperative management, surgical management resulted in superior Mayo Elbow Performance Index pain scores (40.1 vs 33, P = .04), fewer mechanical symptoms (9% vs 50%, P < .01), and better elbow flexion (141° vs 131°, P = .01) at long-term follow-up. Older patients trended toward increased failure of nonoperative management (P = .06). The presence of an intra-articular loose body predicted failure of nonoperative management (P = .01; odds ratio, 13). Plain radiography and magnetic resonance imaging had poor sensitivities for identifying loose bodies (27% and 40%, respectively). Differences in outcomes after early versus delayed surgical management were not observed. CONCLUSIONS: Nonoperative management of capitellar OCD failed 70% of the time. Elbows that did not undergo surgery had slightly more symptoms and decreased functional outcomes compared with those treated surgically. The greatest predictors of failure of nonoperative treatment were older age and presence of a loose body; however, an initial trial of nonoperative treatment did not adversely impact the success of future surgery. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Arthrofibrosis is characterized by excessive extracellular matrix (ECM) deposition that results in restricted joint motion after total knee arthroplasties (TKAs). Currently, treatment options are limited. Therefore, an in vitro model of knee-related myofibroblastogenesis is valuable to facilitate investigation of the arthrofibrotic process, diagnostic and therapeutic options. In this study, we obtained intraoperative posterior capsule (PC), quadriceps tendon (QT), and suprapatellar pouch (SP) tissues from the knees of four patients undergoing primary TKAs for osteoarthritis. From these tissues, we isolated primary cells by the outgrowth method and subsequently characterized these cells in the absence and presence of the pro-myofibroblastic cytokine, transforming growth factor beta 1 (TGFβ1). Light microscopy of knee outgrowth cells revealed spindle-shaped cells, and immunofluorescence (IF) analysis demonstrated staining for the fibroblast-specific markers TE-7 and vimentin (VIM). These knee outgrowth fibroblasts differentiated readily into myofibroblasts as reflected by enhanced α-smooth muscle actin (ACTA2) mRNA and protein expression and increased mRNA expression of collagen type 1 (COL1A1) and type 3 (COL3A1) with collagenous matrix deposition in the presence of TGFβ1. Outgrowth knee fibroblasts were more sensitive to TGFβ1-mediated myofibroblastogenesis than adipose-derived mesenchymal stromal/stem cells (MSCs). While outgrowth knee fibroblasts isolated from three anatomical regions in four patients exhibited similar gene expression, these cells are distinct from other fibroblastic cell types (i.e., Dupuytren's fibroblasts) as revealed by RNA-sequencing. In conclusion, our study provides an in vitro myofibroblastic model of outgrowth knee fibroblasts derived from patients undergoing primary TKA that can be utilized to study myofibroblastogenesis and assess therapeutic strategies for arthrofibrosis.

Background The ‘OPTIMAL’ (Optimizing Performance Through Intrinsic Motivation and Attention for Learning) theory of motor learning suggests that autonomy, external focus of attention, and perceived competence can improve learning of simple motor tasks. The authors hypothesized that enhanced (vs. routine) autonomy and external (vs. internal) focus of attention would improve first-try performance of two medical motor tasks. Methods The authors conducted a randomized two-by-two factorial design study with high school students as participants. Task instructions promoted either enhanced or routine autonomy, and either external or internal focus of attention. These conditions were replicated in a crossover design for two common medical tasks (chest compressions on a manikin and a Fundamentals of Laparoscopic Surgery peg transfer task). Primary outcomes were objective measures of task performance (chest compression deviation from target depth; peg transfer time with penalties for errors). Secondary outcomes included subjective perceptions of confidence, autonomy, and workload. Results One hundred thirty-three high school students participated in this study. The primary outcomes concerning enhanced vs. routine autonomy demonstrated no statistically significant difference in either task (chest compression depth deviation: difference -0.7 mm [score range 0 to 37.5 mm]; 95% confidence interval (CI95) -3.85, 2.41; p = .65; peg transfer penalized time: rate ratio 1.03; CI95 0.91, 1.31; p = .79). The authors likewise found no statistically significant difference for external vs. internal focus of attention (depth deviation: difference 1.1 mm; CI95 -2.04, 4.17; p = .50; penalized time: rate ratio 0.89; CI95 0.75, 1.13; p = .33). The authors found no statistically significant differences for either comparison in confidence, autonomy and workload (p > .09; differences ranged from -0.83 to 0.79 [scale range 0 to 10]). Conclusions First-try performance of chest compressions and peg transfer by novice learners is not significantly affected by enhanced (vs. routine) autonomy or external (vs. internal) focus of attention.

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.

The ultimate means of functional restoration of joints with end stage arthritis is prosthetic replacement. Even though there is reluctance to replace the joint of a younger individual, the mean age of joint replacement continues to decrease. This is due to three factors: 1) social expectations, 2) uncertainty with many joint preservation procedures and 3) the ever-increasing reliability and longevity of prosthetic replacement. Unfortunately, the elbow does not share in these advantageous trends to the extent as is the case for the hip, knee and shoulder. Social pressure for restoration of normal or near normal function is certainly present, but the desired improvement of longevity and fewer restrictions of activity have not been documented. Hence, possibly somewhat disproportionately to other joints, there is great need for a reliable and functional non replacement joint reconstruction option. For most other joints, fusion is the ultimate non replacement option. Further, for most joints an optimum position has been defined to allow the greatest chance of normal function of the individual. Unfortunately, there is no truly ‘optimum’ functional position of elbow fusion, and the recommended 90° of flexion is considered the ‘least worse’ position. Further, unfortunately, elbow fusion dysfunction cannot be mitigated by compensated shoulder motion. Hence, while there is little experience in general with interposition arthroplasty of the elbow, in the authors' opinion it remains the treatment of choice in some individuals and in certain circumstances for the reasons explained above. In our judgment, the reason for avoiding this procedure is that it is technically difficult, the absolute frequency of need is not great, and outcomes do appear to be a function of experience and technique. Based on these considerations, in this chapter we review the current indications and assessment and selection considerations. Emphasis is placed on our current technique with technical tips to enhance the likelihood of success and longevity. We conclude with a review of expectations based on current literature.

Purpose To analyze the available literature pertaining to the indications, outcomes, and complications of both microfracture (MFX) and simple debridement for capitellar osteochondritis dissecans (OCD). Methods A comprehensive literature review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) criteria. Studies were included if they evaluated OCD of the capitellum that underwent either arthroscopic debridement (AD) or MFX. The risk of bias was assessed using the Methodological Index for Non-randomized Studies (MINORS) scale. Patient demographic characteristics, imaging findings, return-to-sport rates, patient-reported outcomes, range of motion (ROM), complications, failures, and reoperations were recorded. Results Eleven studies with 327 patients (332 elbows) met the inclusion criteria. Methodological Index for Non-randomized Studies (MINORS) scores ranged from 63% to 75% and showed considerable heterogeneity. Both AD and MFX showed improvement in patient outcome scores, ROM, and return to play, although the data precluded relative conclusions. Improvement in motion after MFX ranged from 4.9° to 5° of flexion, 5° to 22.6° of extension, 1° to 2° of pronation, and 0.5° to 2° of supination, whereas after AD, it ranged from –4° to 6° of flexion and –0.4° to 14° of extension, with prono-supination noted in only 1 study. The rate of return to play at a similar level of preinjury athletic competition ranged from 55% to 75% after MFX and from 40% to 100% after AD. Lesion location was discussed in only 1 study. Postoperative imaging trended toward early degenerative changes, most commonly of the radial head. Complications were only reported in 1 MFX study; in all cases, the complication was transient ulnar nerve neurapraxia. Reoperation rates ranged from 0% to 10%, and reoperation was most commonly performed to address radial head enlargement. Five studies reported no reoperations. Conclusions Both AD and MFX for capitellar OCD appear to yield excellent improvements in pain, ROM, patient outcome scores, and return to sport. Given that comparable mid-term outcomes can be achieved with debridement alone, without the use of MFX, similarly to recent prospective studies in the knee, AD alone may be a reasonable approach to relatively small OCD defects. Level of Evidence Level IV, systematic review of studies, all Level IV evidence.

Total elbow arthroplasty (TEA) is associated with a relatively high complication rate, and exceptionally catastrophic complications might lead to amputation. The purpose of this study was to determine the incidence and aetiology of amputation performed at our institution in upper extremity limbs with a prior TEA. Between 1973 and 2018, 1906 consecutive TEAs were performed at our institution. Upper extremity amputation was performed in seven (0.36%) elbows with five transhumeral amputations and two shoulder disarticulations. The group consisted of five females and two males with a mean age of 64 years (range, 37–80). The index TEA had been performed for rheumatoid arthritis (n = 2), rheumatoid arthritis with acute fracture (n = 2), radiation associated nonunion (n = 2), and metastatic cancer (n = 1). Mean follow-up after amputation was three years (range, 3 months–5 years). Mean time between amputation and TEA was 5 years (range, 2 months–13 years). The indications for amputation included uncontrolled deep infection in six (86%) elbows and tumor recurrence in one (14%) elbow. Only one elbow (14%) was fitted with a prosthesis. Six (86%) patients died at a mean of three years (range, 3 months–5 years) after amputation. The results of this study highlight a low incidence of amputation after TEA. Most amputations were the direct result of TEA complications, with infection being the most common cause of amputation. Outcomes after amputation are concerning, with poor overall survival and few patients being fit for a prosthesis.

Radial head arthroplasty (RHA) is an important tool in the acute treatment of comminuted radial head and neck fractures. RHA is also performed in a delayed manner after failed open reduction and internal fixation, for fracture malunion or nonunion, and other chronic post-traumatic elbow disorders where restoration of the lateral column of the elbow is considered necessary. The relative efficacy and longevity of acute vs. delayed RHA is unknown. We sought to compare clinical, radiographic, and patient-reported outcomes between these groups.We identified patients ≥18 years old who underwent an RHA between 2000 and 2018 and then extracted 135 total elbows with a mean follow-up of 2.3 years that sustained isolated radial head fractures (30%), terrible triad injuries (66%), or Essex-Lopresti injuries (4%). The acute cohort (RHA:12 weeks) contained 101 elbows that underwent surgery at a mean of 0.6 weeks (range, 0 days to 7 weeks, 96% 2 weeks) from injury, whereas the delayed cohort (RHA: 12 weeks to 2 years) contained 34 elbows that underwent surgery at a mean of 36 weeks (range, 14-82 weeks) from injury. Patients in the acute group had a higher percentage of terrible triad injuries (75% vs. 40%, P .001) and Mason 3 fractures (98% vs. 45%, P .001).At the final follow-up, 13 of 101 patients in the acute cohort (13%) and 7 of 34 patients in the delayed cohort (21%) required implant revision or resection. A total of 25 patients (25%) in the acute cohort and 12 patients (35%) in the delayed cohort required a reoperation. Kaplan-Meier 2-year survival estimates free of implant resection or revision (90% acute, 86% delayed) and reoperation (76% acute, 70% delayed) were similar between groups. In patients with 5-year follow-up, there was an increased rate of revision or resection in the delayed group (30% vs. 13%). Two-year survival estimates free of radiographic loosening were 80% in the acute cohort vs. 57% in the delayed cohort (P = .04). Mayo Elbow Performance Score at 2 years demonstrated mean scores of 83 and 79 in the acute and delayed groups, respectively, with 71% of the acute cohort and 64% of the delayed cohort achieving good or excellent scores.Our results demonstrated that although 2-year Kaplan-Meier survival free of revision or resection estimates and reoperation rates was equivalent between the groups, the delayed group experienced worse Mayo Elbow Performance Score outcomes, a higher revision or resection rate at 5 years, and an increased rate of radiographic loosening.

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.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.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.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.Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Elbow arthroscopy has increased in frequency as its indications have widened. Despite this growth, a learning curve has not yet been defined.We hypothesized that there would be significant differences in perspective between trainees and established surgeons for the number of cases needed to reach each skill level and what they felt are the most valuable training tools.Orthopedic attending physicians and trainees were asked to complete a questionnaire assessing participant demographics, case volumes required to reach defined skill levels (novice, safe, competent, proficient, and expert), and the efficacy of various learning methodologies for elbow arthroscopy. The value of educational methods was assessed using a 5-point Likert scale (1 = not at all valuable; 5 = extremely valuable).The study population consisted of 323 total participants, of whom 224 (69.3%) were attending surgeons and 99 (30.7%) were trainees (resident or fellow physicians). According to the attending physicians, the mean numbers of cases needed to reach each skill level were 19 to be safe, 42 to be competent, 93 to be proficient, and 230 to be expert. These case numbers were not significantly different from the perspectives of trainees. Across the respondents, there were no significant differences in the number of cases needed to reach each level of skill based on the respondents' level of training, years of experience, type of fellowship, or self-reported skill level.Although both groups highly valued live surgery (4.7 of 5) and cadaveric practice (4.6 of 5) for acquiring skill, attendings placed higher value on reading (4.0 vs. 3.3, P.001), videos/live demos (4.2 vs. 3.6, P .001), and formal courses (4.5 vs. 4.1, P .001) than trainees. Both groups place relatively low value on surgical simulators (2.8-3.6).There was considerable agreement among attending surgeons and trainees in terms of the number of cases needed to attain various skill levels of elbow arthroscopy, which was consistent regardless of fellowship background, self-reported skill level, career length, and elbow arthroscopy case volume. However, there was some disagreement between attending surgeons and trainees over the most valuable methods for acquiring surgical skill with trainees placing less value on textbooks, surgical videos, and formal courses compared with attending surgeons. An understanding of the elbow arthroscopy learning curve will help trainees and their training programs establish case volume targets before safe, independent practice. Future studies should aim to clinically validate this learning curve.

Background Pathologic fibrosis is characterized by dysregulation of gene expression with excessive extracellular matrix production. The genetic basis for solid organ fibrosis is well described in the literature. However, there is a paucity of evidence for similar processes in the musculoskeletal (MSK) system. The purpose of this review is to provide an overview of existing evidence of genetic predisposition to pathologic fibrosis in the cardiac, pulmonary, and MSK systems, and to describe common genetic variants associated with these processes. Methods A comprehensive search of several databases from 2000 to 2019 was conducted using relevant keywords in the English language. Genes reported as involved in idiopathic fibrotic processes in the heart, lung, hand, shoulder, and knee were recorded by 2 independent authors. Results Among 2373 eligible studies, 52 studies investigated genetic predisposition in terms of variant analysis with the following organ system distribution: 36 pulmonary studies (69%), 15 hand studies (29%), and 1 knee study (2%). Twenty-two percent of gene variants identified were associated with both pulmonary and MSK fibrosis (ie, ADAM, HLA, CARD, EIF, TGF, WNT, and ZNF genes). Genetic variants known to be involved in the MSK tissue development or contractility properties in muscle were identified in the pulmonary fibrosis. Conclusion Despite shared genetic variations in both the lung and hand, there remains limited information about genetic variants associated with fibrosis in other MSK regions. This finding establishes the necessity of further studies to elucidate the genetic determinants involved in the knee, shoulder, and other joint fibrotic pathways. Level of evidence Level III.

To examine diagnostic and therapeutic utility of novel ultrasound-guided perineural injection of posterior antebrachial cutaneous nerve in chronic lateral elbow pain. We performed a retrospective analysis of ultrasound-guided perineural injection of the posterior antebrachial cutaneous nerve with local anesthetic with or without corticosteroid in patients with chronic lateral elbow pain. Data variables collected included patient demographics, illness course, diagnostic ultrasound findings, immediate pre- and post-injection pain using numeric rating pain scale between 0 and 10, injection complications, and post-injection outcomes. Fifteen patients (9 females and 6 males) with average age 46.9 (range 16–69 years) underwent 20 perineural injections between 2009 and 2019. Patients had on average 84% reduction in pain immediately after the injection (median pre- and post-procedure numeric rating pain scale of 6 and 0, respectively, p

Background When revision elbow arthroplasty is required in the presence of structural proximal ulnar bone loss and triceps insufficiency, structural ulnar bone-grafting and triceps reconstruction are both required to reconstruct the skeleton and to restore active extension. We have developed a technique utilizing a structural proximal ulnar allograft with its attached triceps as an allograft-prosthetic composite (APC) to provide reconstruction of the proximal ulnar bone and deficient extensor mechanism with the same allograft. Methods Between 2010 and 2017, the senior author performed 10 revision elbow arthroplasties using a proximal ulnar allograft with its intact triceps tendon allograft. The allograft ulna was combined with an ulnar component in an APC fashion, whereas the remaining triceps was repaired to the triceps allograft. Indications for a revision surgical procedure included aseptic loosening in 4 elbows, periprosthetic ulnar fracture with component loosening in 2 elbows, and the second stage of a 2-stage reimplantation in 4 elbows. Two elbows also required humeral APCs due to associated structural humeral bone loss. Postoperatively, all elbows were immobilized in extension for 6 weeks. The mean follow-up time was 45 months (range, 24 to 76 months). Results Revision elbow arthroplasty resulted in pain improvement in all elbows in a 10-point visual analog scale. The mean flexion-extension arc was 95°, the mean Mayo Elbow Performance Score was 76 points (range, 45 to 95 points), and the mean triceps strength score was 4. There were 6 reoperations: 3 for humeral loosening, 1 for deep infection, 1 for fracture of the ulnar allograft, and 1 for wound debridement and closure. For the 8 elbows with an intact ulnar reconstruction, no ulnar components were radiographically loose, and the ulnar graft was considered radiographically intact and healed in 8 elbows. Conclusions Reconstruction of the proximal part of the ulna and triceps in failed elbow arthroplasties with structural ulnar bone loss can be effectively accomplished using a structural proximal ulnar allograft as an APC with the preserved triceps tendon for the extensor mechanism reconstruction, but the procedure is associated with an expected high reoperation rate, as is the case in complex revision elbow arthroplasty. Level of evidence Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Arthrofibrosis is an abnormal histopathologic response, is debilitating for patients, and poses a substantial unsolved clinical challenge. This study characterizes molecular biomarkers and regulatory pathways associated with arthrofibrosis by comparing fibrotic and non-fibrotic human knee tissue. The fibrotic group encompasses 4 patients undergoing a revision total knee arthroplasty (TKA) for arthrofibrosis (RTKA-A) while the non-fibrotic group includes 4 patients undergoing primary TKA for osteoarthritis (PTKA) and 4 patients undergoing revision TKA for non-arthrofibrotic and non-infectious etiologies (RTKA-NA). RNA-sequencing of posterior capsule specimens revealed differences in gene expression between each patient group by hierarchical clustering, principal component analysis, and correlation analyses. Multiple differentially expressed genes (DEGs) were defined in RTKA-A versus PTKA patients (i.e., 2059 up-regulated and 1795 down-regulated genes) and RTKA-A versus RTKA-NA patients (i.e., 3255 up-regulated and 3683 down-regulated genes). Our findings define molecular and pathological markers of arthrofibrosis, as well as novel potential targets for risk profiling, early diagnosis and pharmacological treatment of patients.

Aims Arthrofibrosis is a relatively common complication after joint injuries and surgery, particularly in the knee. The present study used a previously described and validated rabbit model to assess the biomechanical, histopathological, and molecular effects of the mast cell stabilizer ketotifen on surgically induced knee joint contractures in female rabbits. Methods A group of 12 skeletally mature rabbits were randomly divided into two groups. One group received subcutaneous (SQ) saline, and a second group received SQ ketotifen injections. Biomechanical data were collected at eight, ten, 16, and 24 weeks. At the time of necropsy, posterior capsule tissue was collected for histopathological and gene expression analyses (messenger RNA (mRNA) and protein). Results At the 24-week timepoint, there was a statistically significant increase in passive extension among rabbits treated with ketotifen compared to those treated with saline (p = 0.03). However, no difference in capsular stiffness was detected. Histopathological data failed to demonstrate a decrease in the density of fibrous tissue or a decrease in α-smooth muscle actin (α-SMA) staining with ketotifen treatment. In contrast, tryptase and α-SMA protein expression in the ketotifen group were decreased when compared to saline controls (p = 0.007 and p = 0.01, respectively). Furthermore, there was a significant decrease in α-SMA (ACTA2) gene expression in the ketotifen group compared to the control group (p < 0.001). Conclusion Collectively, these data suggest that ketotifen mitigates the severity of contracture formation in a rabbit model of arthrofibrosis. Cite this article: Bone Joint Res 2020;9(6):302–310.

The Tikhoff-Linberg procedure is a limb salvage technique for tumours of the shoulder girdle which preserves function of the hand and elbow; however, shoulder function is limited. A humeral cap endoprosthesis (Stryker Orthopedics, Mahwah, NJ, USA) was developed within the Modular Replacement System (MRS) to act as a functional spacer for these defects; however, the outcomes of this implant have not been described. Thirty-three (17 male, 16 female) patients underwent a Tikhoff-Linberg procedure at our institution. Of these, 17 (11 females, 6 males) were reconstructed with a MRS humerus endoprosthesis. Outcomes and complications were compared between patients who were reconstructed (n = 17) and those who were not (n = 16). Complications occurred in 14 (42%) patients, with more complications in patients who were reconstructed (n = 11, 65% vs. n = 3, 19%, p = 0.01). Endoprosthetic complications included stress shielding of the bone/prosthesis interface (n = 7, 41%) and subluxation/instability (n = 5, 29%), leading to a revision surgery in two (12%). Post-operatively, the mean Musculoskeletal Tumor Society Score (MSTS93) was 67 ± 11%, with no difference in the mean MSTS93 between patients who were reconstructed and those who were not (67 ± 10% vs. 68 ± 12%, p = 0.77). Reconstruction with a MRS humerus cap endoprosthesis resulted in a high rate of complications following a Tikhoff-Linberg procedure. Stress shielding and subluxation were common, and as such, the use of this prosthesis is limited to cases where a standard implant is not a feasible option.

Background The utilization of reverse shoulder arthroplasty (RSA) has increased over time. Toxic increases of metal ion levels have been reported selectively after hip arthroplasty. However, studies evaluating the effect of RSA on in vivo metal ion levels have not been evaluated. Therefore, the purposes of this study were (1) to determine in vivo levels of cobalt, chromium, and nickel in a randomized controlled trial of patients undergoing reverse total shoulder arthroplasty (RSA) with one of four glenosphere sizes, and (2) to identify possible factors affecting changes in metal ion levels. Methods Between May 2016 and September 2018, 72 shoulders with cuff tear arthropathy, massive irreparable cuff tears, or glenohumeral osteoarthritis with posterior subluxation were randomized to undergo RSA using a single implant system and four possible glenosphere options based on size (36 or 40 mm) and offset (+2 mm, +6 mm). In vivo metal ion levels (cobalt, chromium, nickel) and complete blood count (CBC) were assessed preoperatively, 3-months, and 1-year after surgery. Clinical evaluation included pain, motion, Subjective Shoulder Value, ASES scores, and Oxford Shoulder Scores. Results Reverse shoulder arthroplasty led to statistically significant improvements in all outcome measures considered (p Conclusion In this randomized controlled trial of patients undergoing reverse total shoulder arthroplasty with a single design, in vivo levels of cobalt, chromium, and nickel remained reassuringly low. In addition, increase in glenosphere size, offset, or both, did not appear to affect in vivo metal ion levels over the short-term. Longer term studies are needed to further assess the effects of implant modularity on metal ion levels and their potential adverse effects in patients undergoing reverse shoulder arthroplasty. Level of evidence Level I; Randomized Controlled Trial

We investigated endogenous tissue response to a woven and electrospun polydioxanone (PDO) and polycaprolactone (PCL) patch intended for tendon repair. A sheep tendon injury model characterised by a natural history of consistent failure of healing was chosen to assess the biological potential of woven and aligned electrospun fibres to induce a reparative response. Patches were implanted into 8 female adult English Mule sheep. Significant infiltration of tendon fibroblasts was observed within the electrospun component of the patch but not within the woven component. The cellular infiltrate into the electrospun fibres was accompanied by an extensive network of new blood vessel formation. Tendon fibroblasts were the most abundant scaffold-populating cell type. CD45+, CD4+ and CD14+ cells were also present, with few foreign body giant cells. There were no local or systemic signs of excessive inflammation with normal hematology and serology for inflammatory markers three months after scaffold implantation. In conclusion, we demonstrate that an endogenous healing response can be safely induced in tendon by means of biophysical cues using a woven and electrospun patch.

Background Despite good reported outcomes with open reduction and internal fixation of intra-articular distal humerus fractures, complication rates remain high. The objective of this work is to identify factors associated with reoperation. Methods Sixty-three patients treated with open reduction and internal fixation for intra-articular ( Arbeitsgemeinschaft für Osteosynthesefragen type C) distal humerus fractures between 2004 and 2010 were identified using an institutional trauma registry, 62 of which were followed for a minimum of six months. Age, gender, fracture subclassification, open fracture presence, Injury Severity Score, time to definitive surgery, length of postoperative immobilization, and type of approach were recorded. Multivariate analysis was utilized to identify factors independently associated with reoperation. Results Complications requiring reoperation developed in 25 (40.3%) elbows. The most common reasons were wound dehiscence or infection in nine elbows (14.5%) and symptomatic hardware in six (9.6%). During multivariate analysis, only olecranon osteotomy remained an independent predictor for reoperation ( P = 0.043). Discussion Despite improved internal fixation techniques, a high proportion of elbows require reoperation after open reduction and internal fixation for distal humerus fractures. Higher complication rates in fractures fixed through an olecranon osteotomy may reflect additional reoperations due to nonunion of the osteotomy or need to remove hardware from the ulna. Level of evidence Prognostic Level III.

Background The purpose was to determine the risk and outcomes of primary shoulder arthroplasties in patients with immunosuppression who had undergone solid organ transplantation. Methods Using a single institution's total joint registry, we reviewed 30 primary shoulder arthroplasties in 25 post-transplantation patients, including 12 total shoulder arthroplasties, 10 hemiarthroplasties, and 8 reverse shoulder arthroplasties, between 1985 and 2012. Therapy and patient variables were recorded, including immunosuppressive therapy protocols, the date of preceding solid organ transplantation, and specific medications taken in the perioperative period. We matched a cohort of control patients for age, sex, type of implant, and year of surgery at a ratio of 4:1. Two groups were compared regarding mortality risk, complications, and clinical outcomes (pain score, range of motion, and American Shoulder and Elbow Surgeons score). Results No periprosthetic infections occurred in the post-transplantation group at a mean follow-up of 39 months. However, the post-transplantation group showed an increased risk of periprosthetic fractures compared with the control group (hazard ratio, 8.18; 95% confidence interval, 1.22-70.98; P = .03). Despite the increase in fractures, the overall number of complications did not differ between the groups. Furthermore, postoperative shoulder function and outcome scores were not significantly different between patients who had a prior transplant and those who did not. Conclusion Primary shoulder arthroplasty in patients with immunosuppression who underwent solid organ transplantation is a successful procedure to treat glenohumeral arthritis. In contrast, there may be an increased risk of periprosthetic fractures in patients with a history of a solid organ transplant.

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