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The posterolateral corner (PLC) of the knee was regarded as the "dark side" of the knee because of limited understanding of its anatomy and biomechanics and because of poor outcomes after injuries to PLC structures. These injuries rarely occur in isolation, with 28% reported as isolated PLC injuries. Nonoperative treatment of these injuries has led to persistent instability, development of early osteoarthritis, and poor outcomes. Several techniques for reconstruction of the PLC have been described, and all are reported to improve outcomes. Biomechanically validated anatomic reconstructions are preferred because they restore native knee kinematics and improve clinical outcomes without over-constraining the knee.

Background: Recent biomechanical studies have identified sagittal plane posterior tibial slope as a potential risk factor for posterior cruciate ligament (PCL) injury because of its effects on the kinematics of the native and surgically treated knee. However, the literature lacks clinical correlation between primary PCL injuries and decreased posterior tibial slope. Purpose/Hypothesis: The purpose of this study was to retrospectively compare the amount of posterior tibial slope between patients with PCL injuries and age/sex-matched controls with intact PCLs. It was hypothesized that patients with PCL injuries would have a significantly decreased amount of posterior tibial slope when compared with patients without PCL injuries. Study Design: Case-control study; Level of evidence, 3. Methods: Patients who underwent primary PCL reconstruction without anterior cruciate ligament injury between 2010 and 2017 by a single surgeon were retrospectively analyzed. Measurements of posterior tibial slope were performed with lateral radiographs of PCL-injured knees and matched controls without clinical or magnetic resonance imaging evidence of ligamentous injury. Mean values of posterior tibial slope were compared between the groups. Inter- and intrarater agreement was assessed for the tibial slope measurement technique via a 2-way random effects model to calculate the intraclass correlation coefficient (ICC). Results: In sum, 104 patients with PCL tears met the inclusion criteria, and 104 controls were matched according to age and sex. There were no significant differences in age ( P = .166), sex ( P = .345), or body mass index ( P = .424) between the PCL-injured and control groups. Of the PCL tear cohort, 91 patients (87.5%) sustained a contact mechanism of injury, while 13 (12.5%) reported a noncontact mechanism of injury. The mean ± SD posterior tibial slopes were 5.7°± 2.1° (95% CI, 5.3°-6.1°) and 8.6°± 2.2° (95% CI, 8.1°-9.0°) for the PCL-injured and matched control groups, respectively ( P < .0001). Subgroup analysis of the PCL-injured knees according to mechanism of injury demonstrated significant differences in posterior tibial slope between noncontact (4.6°± 1.8°) and contact (6.2°± 2.2°) injuries for all patients with PCL tears ( P = .013) and among patients with isolated PCL tears ( P = .003). The tibial slope measurement technique was highly reliable, with an ICC of 0.852 for interrater reliability and an ICC of 0.872 for intrarater reliability. Conclusion: A decreased posterior tibial slope was associated with patients with PCL tears as compared with age- and sex-matched controls with intact PCLs. Decreased tibial slope appears to be a risk factor for primary PCL injury. However, further clinical research is needed to assess if decreased posterior tibial slope affects posterior knee stability and outcomes after PCL reconstruction.

To review the existing variables and their ability to predict recurrence of shoulder instability as it relates to the Instability Severity Index Score (ISIS), as well as evaluate any other pertinent imaging and patient history variables that may impact risk of recurrent anterior instability after arthroscopic Bankart repair.All consecutive patients with recurrent anterior shoulder instability and who had arthroscopic instability repair were identified. Exclusion criteria were prior surgery on the shoulder, posterior or multidirectional instability, instability caused by seizure disorder, or a rotator cuff tear. All ISIS variables were recorded (age20 years, sport type and level, hyperlaxity, Hill-Sachs on anteroposterior external rotation radiograph, loss of glenoid contour on anteroposterior radiograph), as well as additional variables: (1) number of instability events; (2) total time of instability; (3) glenoid bone loss (GBL) percent; and (4) Hill-Sachs measures (H/L/W/D/Volume). Postoperative outcomes were assessed based on the Western Ontario Shoulder Instability Index (WOSI), Single Assessment Numeric Evaluation (SANE) scores, and American Shoulder and Elbow Surgeons (ASES) scores, and recurrent anterior instability. Regression analysis was used to determine preoperative variables that predicted outcomes and failures.There were 217 consecutive patients (209 male patients [96.5%], 8 female patients [3.5%]) who met the inclusion criteria and were all treated with a primary arthroscopic shoulder stabilization during a 3.5-year period (2007-2011), with a mean follow-up time of 42 months (range, 26-58). The mean age at first instability event was 23.9 years (range, 16-48 years) and the mean cumulative ISIS score for the overall group was 3.6 (range, 1-6). Outcomes were improved from mean preoperative (WOSI = 1,050/2,100; ASES = 61.0; SANE = 52.5) to postoperative (WOSI = 305/2,100; ASES = 93.5; SANE = 95.5). A total of 11.5% (25/217) of patients had evidence of recurrent instability (subluxation or dislocation). Additionally, all 25 patients who failed postoperatively also had consistently inferior ASES, SANE, and WOSI outcome scores when compared with successfully treated patients. Factors associated with failure were GBL greater than 14.5% (P.001), total time of instability symptoms greater than 3 months (P = .03), Hill-Sachs volume greater than 1.3 cmAt a mean follow-up of 42 months was an 11.5% failure rate after arthroscopic Bankart stabilization surgery. This study shows no correlation between treatment outcome and the ISIS measure, given a mean score of 3.4 for the overall cohort with little difference identified in those who failed. However, several important parameters previously unidentified were detected including, GBL greater than 14.5%, Hill-Sachs volume greater than 1.3 cmIII (Retrospective Case Series).

Instability of the proximal tibiofibular joint (PTFJ) can present as frank dislocations, vague symptoms of lateral knee pain, discomfort during activity, or symptoms related to irritation of the common peroneal nerve. An accurate preoperative diagnosis is imperative and should include a trial of taping of the PTFJ for a 4- to 6-week time frame before surgical reconstruction is indicated. In the adolescent population, surgical planning can be complicated by the presence of open physes; therefore, caution must be taken to avoid drilling through or placing screw fixation across the physes. Potential complications include growth arrest and limb length discrepancy. Therefore, the purpose of this Technical Note is to describe the surgical technique for addressing PTFJ instability in adolescent patients.

Background: Femoroacetabular impingement (FAI) can lead to hip pain and early joint degeneration. There have been few reports to date on the outcomes of hip arthroscopy for the treatment of FAI in the military population. Purpose/Hypothesis: The purpose of this study was to compare patient demographics with postoperative outcomes after hip arthroscopy for symptomatic FAI and to identify preoperative risk factors for poor outcomes. The hypothesis was that certain preoperative patient characteristics will be predictive of poorer outcomes and that lower outcomes scores will be associated with a higher likelihood of medical separation from the military. Study Design: Case series; Level of evidence, 4. Methods: Retrospective chart review of active-duty and dependent patients older than 18 years who underwent hip arthroscopy for symptomatic FAI from 2009 to 2014 at a single institution. Results: A total of 469 (309 males and 160 females) surgeries were performed on 456 active-duty personnel and 13 dependent civilians, with a mean 2.5-year follow-up. Overall, 39% (n = 179) were able to return to duty (RTD), 18% (n = 82) were medically cleared to return to normal daily activities but did not remain on active duty, and 43% (n = 195) required referral to the Disability Evaluation System (DES). Increasing rank and male sex were positive predictors and Axis 1 psychiatric diagnosis, revision surgery, concomitant psoas tenotomy, multiple medical comorbidities, and complaints of generalized pelvic pain were negative predictors for returning to duty. US Marine Infantry and Special Forces showed improved RTD rates (50%-86%) compared with administrative, more sedentary, occupations (22%). On average, Single Alpha Numeric Evaluation (SANE) and visual analog scale (VAS) scores improved after surgery, with SANE scores improving 37 ± 28 points and VAS scores improving 2.6 ± 2.5 points. The mean postoperative SANE and VAS scores differed significantly between the RTD group and those not returning to duty; 87 and 1.2 points compared with 69 and 3.6 points, respectively ( P < .0001). Conclusion: Hip arthroscopy for the treatment of symptomatic FAI effectively improves pain symptoms and self-reported overall function but shows a much lower than expected return to full, unrestricted active duty in the general active-duty military population. Underlying psychiatric diagnoses, female sex, and more sedentary occupations are associated with lower RTD rates. Furthermore, lower postoperative SANE and VAS scores are associated with lower RTD rates. Only the more active and elite components of the military study population showed RTD rates consistent with previously reported outcomes of return to competitive sports after hip arthroscopy for FAI.

Introduction. Flexor tendon dislocation from the flexor tendon groove posterior of the medial malleolus has been previously described, and may be difficult to diagnose initially, but is amendable to surgical treatment with good outcomes. We present a unique case of unilateral dislocation of the posterior tibialis and flexor digitorum longus tendons with contralateral flexor digitorum longus subluxation that was treated surgically with a good outcome. Case Presentation. A 37-year-old active duty male sustained a dislocation and subluxation of the flexor tendons bilaterally after a forced dorsiflexion injury. Bilateral ankle magnetic resonance imaging revealed the injuries that this patient sustained and aided in surgical planning. Surgical Treatment. Bilateral flexor tendon groove deepening with periosteal flap elevation and retinacular repair. Discussion/Conclusion. This injury has not been previously described in the literature after a forced dorsiflexion mechanism. Advanced imaging is helpful as this injury may be initially misdiagnosed. This case shows that delayed bilateral reconstruction of the flexor tendon grooves and retinacula are reliable methods for pain relief to allow a patient to return to a physically demanding level of function. Levels of Evidence: Level V

Background: Recognition and proper treatment of glenoid bone loss (GBL) are important for successful management of anterior shoulder instability. Although GBL has been described as the amount of bony loss from the front of the glenoid, there is also a fragment of bone that is usually displaced and often undergoes attrition. Thus, due to attritional bone loss (ABL) of the fragment, insufficient bone is left to fully reconstruct the glenoid. Purpose: To (1) evaluate ABL of the glenoid fragment in recurrent anterior shoulder instability and (2) correlate ABL with clinical history, fragment size, and radiographic findings. Study Design: Cross-sectional study; Level of evidence, 3. Methods: GBL was evaluated on 3-dimensional computed tomography (3D CT) en-face view and was measured as percentage loss. The bone fragment size was measured, and attrition of the fragment was determined by evaluation of the amount remaining relative to the initial defect; patients were stratified into minimal (Results: The overall median percentage GBL was 15.3% (interquartile range [IQR], 9.9%-20.0%), with a mean (±SD) percentage GBL of 16.5% ± 9.0%. Study participants had a corresponding median percentage ABL of 75.8% (IQR, 53.8%-95.7%) and a mean percentage ABL of 72.0% ± 24.4%. A total of 61.2% of patients (n = 85) exhibited severe ABL, while 30.2% had moderate ABL and 8.6% had minimal ABL. The total time of instability was significantly associated with percentage of attritional bone loss ( P < .05). In addition, the time of instability was greatest in patients in the third tertile of ABL (≥87.5%; P = .08). A significant difference was found in total time of instability among patients in the highest tertile of ABL (38.6 months) versus both the middle (26.7 months) and lowest (32.8 months) tertiles ( P < .05). Conclusion: The study results indicate that in the majority of patients with recurrent anterior instability, GBL presents with extensive attrition of the bone fragment independent of initial glenoid bone loss; therefore, surgeons should be cognizant that the remaining bone fragment is unable to reconstitute glenoid bone stock. In addition, the results showed more attritional bone loss in patients with a longer duration of instability symptoms, indicating a role for incorporating symptom duration in determining proper management.

Background: Patients with recurrent anterior glenohumeral instability after a failed Latarjet procedure remain a challenge to address. Complications related to this procedure include large amounts of bone loss, bone resorption, and issues with retained hardware that necessitate the need for revision surgery. Purpose: To determine the outcomes of patients who underwent revision surgery for a recurrent shoulder instability after a failed Latarjet procedure with fresh distal tibial allograft. Study Design: Case series; Level of evidence, 4. Methods: All consecutive patients who underwent revision of a failed Latarjet procedure with distal tibial allograft were prospectively enrolled. Patients were included if they had physical examination findings consistent with recurrent anterior shoulder instability. Patients were excluded if they had prior neurologic injury, a seizure disorder, bone graft requirements to the humeral head, or findings of multidirectional or posterior instability. History of shoulder instability was documented, including initial dislocation history, duration of instability, number of prior surgeries, examination findings, plain radiographic and computed tomography (CT) data, and arthritis graded with Samilson and Prieto (SP) classification. All patients were treated with hardware removal, capsular release with subsequent repair, and fresh distal tibial allograft to the glenoid. Outcomes before and after revision were assessed according to the American Shoulder and Elbow Score (ASES), Single Assessment Numerical Evaluation (SANE), and Western Ontario Shoulder Index (WOSI) and statistically compared. All patients underwent a CT scan of the distal tibial allograft at a minimum 4 months after surgery. Results: There were 31 patients enrolled (all males), with a mean age of 25.5 years (range, 19-38 years) and a mean follow-up time of 47 months (range, 36-60 months) after revision with distal tibial allograft. Before distal tibial allograft augmentation, the mean percentage glenoid bone loss was 30.3% (range, 25%-49%). All patients after their Latarjet stabilization had recurrent shoulder dislocation (11/31, 35.5%) or subluxation (20/31, 64.5%), and all patients had symptoms consistent with recurrent shoulder instability upon physical examination. Radiographs demonstrated 2 fixation screws in all cases, mean SP grade was 0.5 (range, 0-3), and CT scans revealed that a mean 78% of the Latarjet coracoid graft had resorbed (range, 37%-100%). Patient-reported outcome scores improved significantly pre- to postoperatively for ASES (40 to 92, P = .001), SANE (44 to 91, P = .001), and WOSI (1300 to 310, P = .001). There were no cases of recurrence, and a final CT scan of the distal tibial revision demonstrated a complete union at the glenoid–distal tibial allograft interface in 92% of patients. Conclusion: The majority of the failed Latarjet procedures included in this study had near-complete resorption of the coracoid graft and hardware complications. At a minimum follow-up time of 36 months, patients who underwent revision treatment for a failed Latarjet procedure with a fresh distal tibial allograft demonstrated excellent clinical outcomes and near-complete osseous union at the glenoid-allograft interface. Although patients evaluated with recurrent anterior shoulder instability after a failed Latarjet procedure remain a challenge to address, fresh distal tibial allograft augmentation is a viable and highly effective revision procedure to treat this patient population.

Objectives: The instability severity index score (ISIS) was designed to predict the risk of recurrence after arthroscopic instability shoulder surgery and to better predict those who would benefit from an open or bone transfer operation. Although this score has been widely disseminated to predict recurrence, there are certain areas in which preoperative assessment is limited, especially in radiographic workup. The objective of this study was to examine the validity of ISIS based on its existing variables, as well as to evaluate additional imaging and patient history variables pertinent to the potential redevelopment of a new score to assess risk of recurrent anterior instability following an arthroscopic Bankart repair. Methods: All consecutive patients were prospectively enrolled with recurrent anterior shoulder instability who subsequently underwent an arthroscopic stabilization with minimum 24 months follow-up. Exclusion criteria included, prior surgery on the shoulder, posterior or multidirectional instability, or a rotator cuff tear. All instability severity index score variables were recorded (age Results: There were 217 consecutive patients (209 male-96.5%, 8 female-3.5%) who met criteria and were all treated with a primary arthroscopic shoulder stabilization during a 3.5-year period (2007-2011), with mean follow-up of 42 (range, 26-58 mos). The mean age at first instability event was 23.9 (range, 16-48), with 55% right shoulder affected, 60% dominant shoulder. Outcomes were improved from mean scores preoperative (WOSI=1050/2100, ASES=61.0, SANE=52.5) to postoperative (WOSI=305/2100, ASES=93.5, SANE=95.5), and 11.5% (25/217) had evidence or recurrent instability or subluxation. A total of 51/217 were 20 years or under, hyperlaxity in 5, Hill Sachs on internal rotation XR in 77, glenoid contour on AP XR in 41, with an overall mean ISIS score of 3.6. Factors associated with failure were glenoid bone loss greater than 14.5%(p11.5 months(p 1.3 cm3 with H>1.5 cm, W>1.0 cm and D>5 mm(p0.45), sports participation, and Instability Severity Score (mean=3.4 success, vs 3.9 failure, p>0.44). Conclusion: At nearly four years of follow-up, there was an 11.5% failure rate of scope stabilization surgery. However, there was no correlation between treatment outcome and the ISIS measure given a mean score of 3.4 with little difference identified in those that failed. However, several important parameters previously unidentified were detected including, glenoid bone loss >14.5%, Hill Sachs volume >1.3 cm3, and time length of instability symptoms. Therefore, the ISIS measure may need to be redesigned in order to incorporate variables that more accurately portray the actual risk of failure following arthroscopic stabilization.

Background: A flattened posterior tibial slope may cause excessive unwanted stress on the posterior cruciate ligament (PCL) reconstruction graft and place patients at risk for PCL reconstruction graft failure. To date, there is a paucity of biomechanical studies evaluating the effect of posterior tibial slope on the loading properties of single-bundle (SB) and double-bundle (DB) PCL grafts. Purpose/Hypothesis: The purpose of this study was to quantify the effect of sagittal plane tibial slope on PCL reconstruction graft force at varying slopes and knee flexion angles for SB and DB PCL reconstructions. The null hypothesis was that there would be no differences in SB or DB PCL graft forces with changes in posterior tibial slope or knee flexion angle. Study Design: Controlled laboratory study. Methods: Ten male fresh-frozen cadaveric knees had a proximal posterior tibial osteotomy performed and an external fixator placed for tibial slope adjustment. SB (anterolateral bundle [ALB] only) and DB PCL reconstruction procedures were performed and tested consecutively for each specimen. The ALB and posteromedial bundle graft forces were recorded before (unloaded force) and after (loaded force) compression with a 300-N axial load. Unloaded and loaded graft forces were tested at flexion angles of 45°, 60°, 75°, and 90°. Tibial slope was varied between −2° and 16° of posterior slope at 2° increments under these test conditions. Results: Modeling for unloaded testing revealed that tibial slope had an independently significant and linear decreasing effect on the force of all PCL grafts regardless of flexion angle (coefficient = −1.0, SE = 0.08, P < .001). Higher knee flexion angles were significantly associated with higher unloaded graft force for all PCL grafts ( P < .001). After the graft was subjected to loading, tibial slope also had an independently significant and linear decreasing effect on the loaded force of all PCL grafts regardless of flexion angle (coefficient = −0.70, SE = 0.11, P < .001). The ALB graft of DB reconstructions had a significantly lower loaded graft force than the ALB graft of the SB PCL reconstruction (coefficient = 14.8, SE = 1.62, P < .001). The posteromedial bundle graft had a significantly lower loaded graft force than the ALB graft in both reconstruction states across all flexion angles (both P < .001). Higher knee flexion angles were also significantly associated with higher loaded graft force for all graft constructs ( P < .001). Conclusion: PCL graft forces increased as tibial slope decreased (flattened) in the loaded and unloaded states. An increased posterior tibial slope was protective of PCL reconstruction grafts. The findings of this study support the effect of tibial slope on PCL grafts that has been noted clinically, and a flat tibial slope should be considered a factor when evaluating the cause of failed PCL reconstructions. Clinical Relevance: The authors validated that decreased tibial slope increased the loads on PCL reconstruction grafts. Patients with flat tibial slopes in chronic tears or revision PCL reconstruction cases should be evaluated closely for the possible need of a first-stage or concurrent slope-increasing tibial osteotomy.

Background: Anterior and posterior shoulder instabilities are entirely different entities. The presenting complaints and symptoms vastly differ between patients with these 2 conditions, and a clear understanding of these differences can help guide effective treatment. Purpose: To compare a matched cohort of patients with anterior and posterior instability to clearly outline the differences in the initial presenting history and overall outcomes after arthroscopic stabilization. Study Design: Cohort study; Level of evidence, 2. Methods: Consecutive patients with either anterior or posterior glenohumeral instability were prospectively enrolled; patients were excluded if they had more than 10% anterior or posterior glenoid bone loss, multidirectional instability, neurologic injury, or prior surgery. Patients were assigned to anterior or posterior shoulder instability groups based on the history and clinical examination documenting the primary direction of instability, with imaging findings to confirm a labral tear associated with the specific direction of instability. Preoperative demographic data, injury history, and overall clinical outcome scores (American Shoulder and Elbow Surgeons [ASES], Single Assessment Numeric Evaluation [SANE], and Western Ontario Shoulder Index [WOSI]) were assessed and compared statistically between the 2 cohorts. Patients were indicated for surgery if they elected to proceed with surgical management or did not respond to a course of nonoperative management. Results: The study included 103 patients who underwent anterior stabilization (mean age, 23.5 years; range, 18-36 years) and 97 patients who underwent posterior stabilization (mean age, 24.5 years; range, 18-36 years). The mean follow-up was 39.7 months (range, 24-65 months), and there were no age or sex differences between the groups. No patients were lost to follow-up. The primary mechanism of injury in the anterior cohort was a formal dislocation event (82.5% [85/103], of which 46% [39/85] required reduction by a medical provider), followed by shoulder subluxation (12%, 12/103), and “other” (6%, 6/103; no forceful injury). No primary identifiable mechanism of injury was found in the posterior cohort for 78% (75/97) of patients; lifting and pressing (11%, 11/97) and contact injuries (10% [all football blocking], 10/97) were the common mechanisms that initiated symptoms. Only 10 patients (10.3%) in the posterior cohort sustained a dislocation. The most common complaints for patients with anterior instability were joint instability (80%) and pain with activities (32%). In the posterior cohort, the most common complaint was pain (90.7%); only 13.4% in this cohort reported instability as the primary complaint. Clinical outcomes after arthroscopic stabilization were significantly improved in both groups, but the anterior cohort had significantly better outcomes in all scores measured: ASES (preoperative: anterior 58.0, posterior 60.0; postoperative: anterior 94.2 vs posterior 87.7, P < .005), SANE (preoperative: anterior 50.0, posterior 60.0; postoperative: anterior 92.9 vs posterior 84.9, P < .005), and WOSI (preoperative: anterior 55.95, posterior 60.95; postoperative: anterior 92% of normal vs posterior 84%, P < .005). Conclusion: This study outlines clear distinctions between anterior and posterior shoulder instability in terms of presentation and clinical findings. Patients with anterior instability present primarily with an identifiable mechanism of injury and complaints of instability, whereas most patients with classic posterior instability have no identifiable mechanism of injury and their primary symptom is pain. Anterior instability outcomes in this matched cohort were superior in all domains versus posterior instability after arthroscopic stabilization, which further highlights the differences between anterior and posterior instability.

Background: Recent clinical studies identified sagittal plane posterior tibial slope as a risk factor for increased postoperative laxity after single-bundle posterior cruciate ligament reconstruction (PCLR). Purpose/Hypothesis: To retrospectively compare the degree of posterior tibial slope and its effect on posterior tibial translation (PTT) after double-bundle (DB) PCLR. Our null hypothesis was that preoperative tibial slope would not be associated with graft laxity. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent DB PCLR between 2010 and 2017 by a single surgeon were retrospectively analyzed. Measurements of posterior tibial slope were performed on lateral radiographs, and PTT was measured with pre- and postoperative kneeling stress radiographs. Simple and multiple linear regression was performed to estimate the unadjusted and adjusted effect of tibial slope on postoperative graft laxity, respectively. Results: A total of 103 patients with posterior cruciate ligament tears and subsequent reconstructions were included. There was a significant reduction of the mean ± SD side-to-side difference in PTT between stress radiographs (preoperative, 10.6 ± 2.7 mm; postoperative, 1.5 ± 2.6 mm; mean difference, 9.1 mm; 95% CI, 8.4-9.8; P < .001). Linear regression analysis revealed no significant correlation between preoperative posterior tibial slope and the amount of side-to-side difference in PTT on postoperative stress radiographs obtained at a mean 18.5 months ( R = −0.115, P = .249). Combined ligament injury (beta = −1.01; 95% CI, −2.00 to −0.01; P = .047) was a significant independent predictor of decreased postoperative side-to-side difference in PTT. Conclusion: Graft laxity, determined by PTT in posterior kneeling stress radiographs, was not influenced by decreased posterior tibial slope after DB PCLRs. The observed results in the current study support the use of DB PCLR. Future studies should be conducted to compare the effect of tibial slope after SB PCLR and DB PCLR at long-term follow-up.

Background: Previous work has reported that increased tibial slope is directly correlated with increased anterior tibial translation, possibly predisposing patients to higher rates of anterior cruciate ligament (ACL) tears and causing higher rates of ACL graft failures over the long term. However, the effect of changes in sagittal plane tibial slope on ACL reconstruction (ACLR) graft force has not been well defined. Purpose/Hypothesis: The purpose of this study was to quantify the effect of changes in sagittal plane tibial slope on ACLR graft force at varying knee flexion angles. Our null hypothesis was that changing the sagittal plane tibial slope would not affect force on the ACL graft. Study Design: Controlled laboratory study. Methods: Ten male fresh-frozen cadaveric knees had a posterior tibial osteotomy performed and an external fixator placed for testing and accurate slope adjustment. Following ACLR, specimens were compressed with a 200-N axial load at flexion angles of 0°, 15°, 30°, 45°, and 60°, and the graft loads were recorded through a force transducer clamped to the graft. Tibial slope was varied between −2° and 20° of posterior slope at 2° increments under these test conditions. Results: ACL graft force in the loaded testing state increased linearly as slope increased. This effect was independent of flexion angle. The final model utilized a 2-factor linear mixed-effects regression model and noted a significant, highly positive, and linear relationship between tibial slope and ACL graft force in axially loaded knees at all flexion angles tested (slope coefficient = 0.92, SE = 0.08, P < .001). Significantly higher graft force was also observed at 0° of flexion as compared with all other flexion angles for the loaded condition (all P < .001). Conclusion: The authors found that tibial slope had a strong linear relationship to the amount of graft force experienced by an ACL graft in axially loaded knees. Thus, a flatter tibial slope had significantly less loading of ACL grafts, while steeper slopes increased ACL graft loading. Our biomechanical findings support recent clinical evidence of increased ACL graft failure with steeper tibial slope secondary to increased graft loading. Clinical Relevance: Evaluation of the effect of increasing tibial slope on ACL graft force can guide surgeons when deciding if a slope-decreasing proximal tibial osteotomy should be performed before a revision ACLR. Overall, as slope increases, ACL graft force increases, and in our study, flatter slopes had lower ACL graft forces and were protective of the ACLR graft.

Blood flow restriction (BFR) training involves occluding venous outflow while maintaining arterial inflow by the application of an extremity tourniquet after surgery. BFR ultimately reduces oxygen delivery to muscle cells, similar to an anaerobic environment, and allows patients to exercise with low resistance and stimulates muscle hypertrophy and strength using heavy resistance. Thus orthopaedic surgeons and physical therapists are incorporating this type of training into their postoperative rehabilitation protocols, particularly after injuries or surgical procedures about the knee joint. The purpose of this Technical Note is to describe a BFR clinical application technique and to report on the indications, safety considerations, and postoperative knee surgery rehabilitation protocols for BFR.

Background: American football is a leading cause of sports-related injuries, with the knee, ankle, and shoulder most commonly involved. Purpose/Hypothesis: The purpose of this study was to describe the epidemiology, characteristics, and imaging findings of ankle injuries in football players at the National Football League (NFL) Combine and determine the relationship to player position. We hypothesized that there would be a high relative incidence of ankle injuries in these players compared with other sports and that there would be a direct correlation between the incidence of ankle injuries and player position. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective chart review of data collected from NFL Combine participants between 2009 and 2015 was performed. Patient demographics, history, physical examination results, and imaging findings were reviewed. Results: Of 2285 players, 1216 (53.2%) had a history of ankle injuries; of these, 987 (81.2%) had unilateral injuries, while 229 (18.8%) had bilateral injuries (total of 1445 ankles injured). This included 1242 ankle sprains (86.0% of ankle injuries): 417 (33.6% of sprains) high and 930 (74.9%) low. The most common soft tissue injuries were to the anterior talofibular ligament (n = 158, 12.7% of sprains) and syndesmosis (n = 137, 11.0%). Of all players at the NFL Combine with radiographs, 131 (10.9%) had evidence of an ankle fracture, all of which had healed. Magnetic resonance imaging (MRI) identified 66 players (28.9% of players at the combine who underwent MRI) with articular cartilage injuries: 62 involving the talus and 16 involving the tibia. Furthermore, 85 players (37.3% of players with MRI) with tendon injuries were identified: 26 Achilles, 55 peroneal, 3 flexor hallucis longus, and 19 posterior tibial. A total of 611 players (50.6% of players with radiographs) had signs of arthrosis on radiography. Running backs (61.9%), offensive linemen (60.3%), and tight ends (59.4%) had the highest rates of ankle injuries by position, while kickers/punters (23.3%) and long snappers (37.5%) had the lowest. Conclusion: Prior ankle injuries were present in more than 50% of elite college football players attending the NFL Combine. The rate of these ankle injuries varied by player position: offensive linemen, running backs, and tight ends had the highest overall rates, while special teams players had the lowest. Additional prospective work is needed to determine the impact of prior injuries on future playing career.

A snapping biceps tendon is an infrequently seen and commonly misdiagnosed pathology, leaving patients with persistent symptoms that can be debilitating. Patients will present with a visible, audible, and/or painful snap over the lateral aspect of their knee when performing squats, sitting in low seats, or participating in activities with deep knee flexion. A thorough knowledge of the anatomy is essential for surgical treatment of this pathology, which is caused by a detachment of the direct arms of the long and short heads of the biceps femoris off the fibular styloid. This Technical Note provides a diagnostic approach, postoperative management, and details of a surgical technique to treat a snapping biceps tendon with an anatomic repair of the long and short head attachments of the biceps femoris to the posterolateral fibular styloid.

Background:Although previous literature has described the relevant anatomy for an open anterior Bankart approach of the shoulder, there is little known regarding the anatomic relationship changes in the neurovascular structures after an open Latarjet procedure.Purpose:To define the neurovascular anatomy of the native shoulder in relation to the coracoid and to define the anatomy after the Latarjet procedure in relation to the glenoid to determine distances to these neurovascular structures with and without neurolysis of the musculocutaneous nerve (MCN) from the conjoint tendon.Study Design:Descriptive laboratory study.Methods:Fourteen fresh-frozen male cadaveric shoulders (7 matched pairs) were utilized. The distances of 7 neurovascular structures (the main trunk of the MCN at its insertion into the conjoint tendon, the MCN at its closest location to the coracoid process, the lateral cord of the plexus, the split of the lateral cord and MCN, the posterior cord of the plexus, the axillary nerve, and the axillary artery) to pertinent landmarks were first measured in the native state in relation to the coracoid. After the Latarjet procedure, these landmarks were measured in relation to the glenoid. In addition, measurements of the MCN distances were performed both with and without neurolysis of the MCN from the conjoint tendon. All measurements were performed using digital calipers and reported as medians with ranges.Results:The median MCN entry into the conjoint tendon was 56.5 mm (range, 43.0-82.2 mm) and 57.1 mm (range, 23.5-92.9 mm) from the tip of the coracoid in the neurolysis group and nonneurolysis group, respectively ( P = .32). After the Latarjet procedure, the median MCN entry into the conjoint tendon was 43.8 mm (range, 20.2-58.3 mm) and 35.6 mm (range, 27.3-84.5 mm) from the 3-o’clock position of the glenoid in the neurolysis and nonneurolysis groups, respectively ( P = .83). The median MCN entry into the conjoint tendon was 35.6 mm (range, 25.1-58.0 mm) and 36.3 mm (range, 24.4-77.9 mm) from the 6-o’clock position in the neurolysis group and nonneurolysis group, respectively ( P = .99). After the Latarjet procedure, the closest neurovascular structures in relation to both the 3-o’clock and 6-o’clock positions to the coracoid were the axillary nerve at a median 27.4 mm (range, 19.8-40.0 mm) and 27.7 mm (range, 23.2-36.1 mm), respectively.Conclusion:This study identified a minimum distance medial to the glenoid after the Latarjet procedure to be approximately 19.8 mm for the axillary nerve, 23.6 mm for the posterior cord, and 24.4 mm and 20.2 mm for the MCN without and with neurolysis, respectively. Neurolysis of the MCN did not significantly change the distance of the nerve from pertinent landmarks compared with no neurolysis, and routine neurolysis may not be indicated. However, the authors still advise that there may be clinical benefit to performing neurolysis during surgery, especially given that the short length of the MCN puts it at risk for traction injuries during the Latarjet procedure.Clinical Relevance:The findings of this study provide an improved understanding of the position of the neurovascular structures after the Latarjet procedure. Knowledge of these minimum distances will help avoid iatrogenic damage of the neurovascular structures when performing procedures involving transfer of the coracoid process.

Blood flow restriction (BFR) therapy is becoming increasingly popular in musculoskeletal injury rehabilitation. In particular, this form of therapy is being utilized more often in the postoperative setting following knee surgery, including anterior cruciate ligament reconstruction. BFR therapy provides patients and clinicians an alternative treatment option to standard muscle strengthening and hypertrophy guidelines in the setting of postoperative pain, weakness, and postoperative activity restrictions that contribute to muscle atrophy. The ability to complete exercise in a low load environment and achieve similar physiological adaptations as high-intensity strength training makes this modality appealing. With poor patient-related outcomes associated with continued muscle atrophy, pain, and muscle weakness, some researchers have investigated BFR training postoperatively following arthroscopic knee surgery with promising results. However, owing to the current paucity of research studies, inconsistency among reported protocols, and mixed results, it may be some time before a mass adoption of BFR therapy is made into the world of orthopaedic rehabilitation. Although the current data is inconclusive, we choose to utilize BFR in postoperative knee patients, regardless of weight-bearing status, for whom maintenance of existing muscle mass or improvement of decreased postoperative strength levels is important. Therefore, the purpose of this expert opinion is to review the background of BFR, describe the clinical evidence of BFR following knee surgery, and report the authors' current recommendations for application of BFR postoperatively.

Background: Bone loss in anterior glenohumeral instability occurs on both the glenoid and the humerus; however, existing biomechanical studies have evaluated glenoid and humeral head defects in isolation. Thus, little is known about the combined effect of these bony lesions in a clinically relevant model on glenohumeral stability. Hypothesis/Purpose: The purpose of this study was to determine the biomechanical efficacy of a Bankart repair in the setting of bipolar (glenoid and humeral head) bone defects determined via computer-generated 3-dimensional (3D) modeling of 142 patients with recurrent anterior shoulder instability. The null hypothesis was that adding a bipolar bone defect will have no effect on glenohumeral stability after soft tissue Bankart repair. Study Design: Controlled laboratory study. Methods: A total of 142 consecutive patients with recurrent anterior instability were analyzed with 3D computed tomography scans. Two Hill-Sachs lesions were selected on the basis of volumetric size representing the 25th percentile (0.87 cm3; small) and 50th percentile (1.47 cm3; medium) and printed in plastic resin with a 3D printer. A total of 21 cadaveric shoulders were evaluated on a custom shoulder-testing device permitting 6 degrees of freedom, and the force required to translate the humeral head anteriorly 10 mm at a rate of 2.0 mm/s with a compressive load of 50 N was determined at 60° of glenohumeral abduction and 60° of external rotation. All Bankart lesions were made sharply from the 2- to 6-o’clock positions for a right shoulder. Subsequent Bankart repair with transosseous tunnels using high-strength suture was performed. Hill-Sachs lesions were made in the cadaver utilizing a plastic mold from the exact replica off the 3D printer. Testing was conducted in the following sequence for each specimen: (1) intact, (2) posterior capsulotomy, (3) Bankart lesion, (4) Bankart repair, (5) Bankart lesion with 2-mm glenoid defect, (6) Bankart repair, (7) Bankart lesion with 2-mm glenoid defect and Hill-Sachs lesion, (8) Bankart repair, (9) Bankart lesion with 4-mm glenoid defect and Hill-Sachs lesion, (10) Bankart repair, (11) Bankart lesion with 6-mm glenoid defect and Hill-Sachs lesion, and (12) Bankart repair. All sequences were used first for a medium Hill-Sachs lesion (10 specimens) and then repeated for a small Hill-Sachs lesion (11 specimens). Three trials were performed in each condition, and the mean value was used for data analysis. Results: A statistically significant and progressive reduction in load to translation was observed after a Bankart lesion was created and with the addition of progressive glenoid defects for each humeral head defect. For medium (50th percentile) Hill-Sachs lesions, there was a 22%, 43%, and 58% reduction in stability with a 2-, 4-, and 6-mm glenoid defect, respectively. For small (25th percentile) Hill-Sachs lesions, there was an 18%, 27%, and 42% reduction in stability with a 2-, 4-, and 6-mm glenoid defect, respectively. With a ≥2-mm glenoid defect, the medium Hill-Sachs group demonstrated significant reduction in translation force after Bankart repair ( P < .01), and for the small Hill-Sachs group, a ≥4-mm glenoid defect was required to produce a statistical decrease ( P < .01) in reduction force after repair. Conclusion: Combined glenoid and humeral head defects have an additive and negative effect on glenohumeral stability. As little as a 2-mm glenoid defect with a medium-sized Hill-Sachs lesion demonstrated a compromise in soft tissue Bankart repair, while small-sized Hill-Sachs lesions showed compromise of soft tissue repair with ≥4-mm glenoid bone loss. Clinical Relevance: Bipolar bony lesions of the glenoid and humeral head occur frequently together in clinical practice. Surgeons should be aware that the combined defects and glenoid bone loss of 2 to 4 mm or approximately 8% to 15% of the glenoid could compromise Bankart repair and thus may require surgical strategies in addition to traditional Bankart repair alone to optimize stability.

Background: Metal screws are traditionally used to fix the coracoid process to the glenoid. Despite stable fixation, metal screws have been associated with hardware complications. Therefore, some studies have advocated for suture button fixation during the Latarjet procedure to reduce the complications associated with screw fixation. Purpose: To biomechanically evaluate the ultimate failure load of a cortical button and self-tensioning suture versus metal screws for coracoid graft fixation during the Latarjet procedure. Study Design: Controlled laboratory study. Methods: Eight matched pairs of fresh-frozen, male cadaveric shoulders (N = 16) underwent the Latarjet procedure. The shoulders of each pair were randomly assigned to 1 of 2 groups: fixation using two 3.75-mm cannulated, fully threaded metal screws or fixation using a double suture button construct. Specimens were secured in a dynamic testing machine and cyclically preconditioned from 2 to 10 N at 0.1 Hz for 10 cycles. After preconditioning, specimens were pulled to failure at a normalized displacement rate of 400% of the measured gauge length per minute. The ultimate failure load and mechanism of failure were recorded for each specimen. Results: The mean ultimate load to failure for screw fixation (226 ± 114 N; 95% CI, 147-305 N) was not significantly different from that for suture button fixation (266 ± 73 N; 95% CI, 216-317 N) ( P = .257). The mean strain at failure for screw fixation (63% ± 21%; 95% CI, 48%-77%) was not significantly different from that for suture button fixation (86% ± 26%; 95% CI, 69%-104%) ( P = .060). The most common mechanism of failure for the screw fixation method was at the bone block drill holes, while an intramuscular rupture at the clamp-muscle interface occurred for the suture button construct. Conclusion: The screw and suture button fixation techniques exhibited comparable biomechanical strength for coracoid bone block fixation of the Latarjet procedure. Clinical Relevance: Metal screws have been reported to be a large contributor to intraoperative and postoperative complications. Therefore, given the results of the current study, a suture button construct may be an alternative to metal screw fixation during the Latarjet procedure. However, further clinical studies are warranted.

Objectives: The purposes of our study were to identify the volume and relative location of Hill-Sachs lesions, measure the amount of glenoid bone loss in patients who have existing Hill-Sachs lesions, and finally draw any correlations that exist between increased glenoid bone loss and increased Hill-Sachs volume. Methods: A total of 217 consecutive three-dimensional (3D) Computed Tomography (CT) scans were reviewed for the presence and measurement of Hill-Sachs volume and location. Hill-Sachs volume was measured by measuring the size of the Hill-Sachs defect in sequential CT images and a 3D model was created to measure the volume of the defect using Osirix (Osirix Imaging Software, Osirix-viewer.com). The Hill-Sachs lesion was then quantified in terms of both location and size. Further, older classification systems were applied to the data to draw comparison. Location of the lesion was measured by utilizing anterior and posterior margins of the lesion in relation to the biceps groove to give a clock face location. The height, depth and length of each lesion were also recorded in its greatest dimension. In addition a 3D model of the individual Hill-Sachs lesion was generated to observe the rough shape of the bony defect. Results: The Hill-Sachs lesion was identified in 60% of patients, N=130. The mean volume of the Hill-Sachs lesions was 1.22 cm3, with a range of 0.13 cm3 to 5.3 cm3. The three dimensional shape of the Hill-Sachs lesion was consistently an orange slice. Using prism measurements the average volume was 3.19 cm3 with a range of 0.33 cm3 to 9.76 cm3. Average arc of the circle of each lesion measured at the axial mid point (10 mm below the top of the humeral head) was 68.9° with a range of 9.49° to 165.88°. The average depth of the lesion was 6.7 mm with a range of 2.8 mm to 11.1 mm. Conclusion: This study identified a unique yet important way to measure the absolute size of the Hill-Sachs lesion in the shoulder. This method is positively correlated with previous measurement systems, but utilizes novel methods to fully measure the unique shape of Hill-Sachs lesions. Using absolute measures not only increases accuracy, but 3D modeling also shows the nature of the defect and location in order to consider operative repair of the lesion. However, the Hill-Sachs lesion only describes one side of the problem, with this data side by side comparison with glenoid bone loss is needed to fully understand the nature of shoulder instability that is a bipolar problem.

Background: Glenoid bone loss is a factor that has been inversely associated with the success of shoulder instability repair. Recently, patients with an anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesion have also been identified as having a higher failure rate after surgical repair. Purpose: To determine differences in the amount of glenoid bone loss and to compare demographic factors of instability in patients with and without ALPSA tears. Study Design: Case-control study; Level of evidence, 3. Methods: Over a 3-year period, all patients (N = 83) who were treated for anterior shoulder instability at a single institution were reviewed retrospectively. A total of 39 (47%) were identified as having an ALPSA lesion and 44 (53%) as having no ALPSA tear. Glenoid bone loss was determined in 2 ways: (1) radiographically by 3-dimensional computed tomography (3D CT) (humeral head digitally subtracted by 3 blinded observers) and (2) with arthroscopic techniques at the time of surgery. Demographic data such as the time from the initial instability event to advanced imaging and surgery were noted. These data were then analyzed with the Student t test to determine any significant differences between the 2 groups. Results: The patients with an ALPSA lesion had more preoperative instability events than those without (8.2 vs 3.6, respectively; P = .04). The mean glenoid bone loss measured by 3D CT was 12.7% (range, 0%-22.3%) for those with ALPSA tears versus 6.25% (range, 0%-23.1%) for those without ( P = .002). The mean duration of total instability for those with ALPSA tears was 42.9 months versus 46.3 months for those without ( P = .95). Lastly, the mean bone loss based on arthroscopic measures was 11.4% for patients with ALPSA tears and 4.3% for those without ALPSA tears ( P = .017). From the existing magnetic resonance imaging/arthrography scans reviewed, 82% of patients could be correctly identified as having an ALPSA lesion. Conclusion: Patients with anterior shoulder instability who have an ALPSA lesion have nearly twice the amount of glenoid bone loss as those with a standard Bankart tear (no ALPSA lesion). Patients with ALPSA lesions had statistically more instability events, and this may be an additional factor in either developing an ALPSA lesion or glenoid bone loss or both.

Three patients were seen for pain and snapping over the lateral aspect of their symptomatic knee during deep knee flexion. On physical examination, each patient had subluxation of the long head of the biceps over the lateral aspect of the fibular head. Each patient underwent an anatomic repair of the torn anterior arms of the short and long biceps femoris to their anatomic insertion sites with suture anchors. All patients had normal return of function without pain or further subluxation events.

The Hill-Sachs lesion is an osseous defect of the humeral head that is typically associated with anterior shoulder instability. The incidence of these lesions in the setting of glenohumeral instability is relatively high and approaches 100% in persons with recurrent anterior shoulder instability. Reverse Hill-Sachs lesion has been described in patients with posterior shoulder instability. Glenoid bone loss is typically associated with the Hill-Sachs lesion in patients with recurrent anterior shoulder instability. The lesion is a bipolar injury, and identification of concomitant glenoid bone loss is essential to optimize clinical outcome. Other pathology (eg, Bankart tear, labral or capsular injuries) must be identified, as well. Treatment is dictated by subjective and objective findings of shoulder instability and radiographic findings. Nonsurgical management, including focused rehabilitation, is acceptable in cases of small bony defects and nonengaging lesions in which the glenohumeral joint remains stable during desired activities. Surgical options include arthroscopic and open techniques.

BackgroundThe amount of medial compartment opening for medial knee injuries determined by valgus stress radiography has not been well documented. The purpose of this study was to develop clinical guidelines for diagnosing medial knee injuries using valgus stress radiography.HypothesisMeasurements of medial compartment gapping can accurately differentiate between normal and injured medial structure knees on valgus stress radiographs.Study DesignControlled laboratory study.MethodsValgus stress radiographs were obtained on 18 adult lower extremities using 10-N·m and clinician-applied valgus loads at 0° and 20° of flexion to intact knees and after sequential sectioning of the superficial medial collateral ligament proximally and distally, the meniscofemoral and meniscotibial portions of the deep medial collateral ligament, the posterior oblique ligament, and the cruciate ligaments. Three independent observers of different experience levels measured all of the radiographs during 2 separate occasions to determine intraobserver repeatability and interobserver reproducibility.ResultsCompared with the intact knee, significant medial joint gapping increases of 1.7 mm and 3.2 mm were produced at 0° and 20° of flexion, respectively, by a clinician-applied load on an isolated grade III superficial medial collateral ligament simulated injury. A complete medial knee injury yielded gapping increases of 6.5 mm and 9.8 mm at 0° and 20°, respectively, for a clinician-applied load. Intraobserver repeatability and interobserver reproducibility intraclass correlation coefficients were .99 and .98, respectively.ConclusionValgus stress radiographs accurately and reliably measure medial compartment gapping but cannot definitively differentiate between meniscofemoral- and meniscotibial-based injuries. A grade III medial collateral ligament injury should be suspected with greater than 3.2 mm of medial compartment gapping compared to the contralateral knee at 20° of flexion, and this injury will also result in gapping in full extension.Clinical SignificanceValgus stress radiographs provide objective and reproducible measurements of medial compartment gapping, which should prove useful for definitive diagnosis, management, and postoperative follow-up of patients with medial knee injuries.

Objectives: Glenoid bone loss (GBL) continues to be a challenge in the management of recurrent anterior shoulder instability. Although the location of and percentage of GBL has been described, there is little information on how much bone is left to reconstruct the glenoid. Thus, the objective of this study is to describe a new GBL classification system that accounts for type of bone defect, amount of attritional loss, and correlate this to age, total time of instability and number of instability events. Methods: A total of 140 patients with recurrent anterior instability underwent an analysis of computed tomography (CT) three-dimensional imaging to assess GBL. The glenoid bone fragment was digitally analyzed (Osirix, Adobe) to qualitatively and quantitatively stratifyeach patient based upon attrition into- Type I “minimal atrittional” (no attrition -33%), Type II “partial attritional” (34 - 66%), and Type III “severe attritional” (67% - complete attrition). Additionally, demographic variables of age, total time of instability, and number of instability events were correlated to type of bone loss. Results: Patients had a mean age of 30.6 (range: 20 - 54) with a demonstrated mean GBL of 16.5% (range 5.1 - 62.3). Furthermore, the mean size of the remaining glenoid bone fragment was 27.8% of the full fragment size. Of 140 participants, 12 had attritional bone loss classified as Type I (12/140 = 8.6% of patients), 45 as Type II (45/140 = 32.1%), and 83 as Type III (83/140 = 59.3%). The mean percent loss for these three categories was 22.2%, 54.4%, and 88.5% respectively. Longer time of instability and more dislocations were associated with type III bone loss, and higher attrition of bone loss. Conclusion: This study highlights that GBL presents in a highly attritional nature and one should be cognizant that the remaining bone fragment does not come close to reconstituting glenoid bone stock. Patients with recurrent instability are predominantly severe attritional (Type III).