Limited Predictive Value of the Instability Severity Index Score: Evaluation of 217 Consecutive Cases of Recurrent Anterior Shoulder Instability.

PURPOSE: 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. METHODS: 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 (age <20 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. RESULTS: 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 cm3 (P = .02), contact sports participation (P = .05), and age 20 years or younger (P < .01). There was no correlation in outcomes with Hill-Sachs on presence of glenoid contour loss on radiograph (P = .07), participation sports, or ISIS (mean = 3.4 success vs 3.9 failure, P > .05). CONCLUSIONS: At 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 cm3, and duration of instability symptoms (>3 months). The ISIS may need to be redesigned to incorporate variables that more accurately portray the actual risk of failure after arthroscopic stabilization, including quantification of both glenoid and humeral head bone loss. LEVEL OF EVIDENCE: III (Retrospective Case Series).

Risk Factors for Recurrence After Arthroscopic Instability Repair-The Importance of Glenoid Bone Loss >15%, Patient Age, and Duration of Symptoms: A Matched Cohort Analysis.

BACKGROUND: Glenoid bone loss (GBL) has been implicated as a risk factor for failure of arthroscopic anterior glenohumeral instability repair. Although certain amounts of GBL are associated with higher recurrence rates, there are limited studies on successes versus failures in these cohorts. PURPOSE: To compare the outcomes of arthroscopic Bankart repair in patients with and without GBL to determine a threshold percentage of GBL that predicts success. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: All consecutive patients who underwent arthroscopic Bankart repair for anterior shoulder instability between 2004 and 2013 were prospectively enrolled. Patients with ≤25% GBL were included. Patients with no GBL were grouped and compared with those having 5% to 25% GBL. Outcomes included Single Assessment Numerical Evaluation, Western Ontario Shoulder Index, and American Shoulder and Elbow Surgeons scores, with evidence of recurrent instability. Patients with and without GBL were statistically compared with respect to outcomes and recurrence rates. RESULTS: Of 434 eligible patients, the cases of 405 (45 female, 360 male; mean age, 27.5 years [range, 18-47 years]) were followed for a mean 61 months (range, 48-96 months). There were 189 (46.6%) with no GBL and 216 (53.3%) with GBL; the mean GBL of the latter cohort was 15% (range, 5%-25%). The mean duration of instability symptoms was 7.9 months (range, 1-21 months) and was significantly longer in the GBL group (P < .05). The mean recurrence rate was 14.8%, which was significantly greater in patients presenting with GBL versus those with none (48/216 [22.2%] vs 12/189 [6.3%]; P < .01). Within the GBL group, GBL ≥15%, duration of symptoms >5 months, and younger age (<20 years) were independent risk factors for failure (P < .01). Patients with any GBL had >4-times greater odds of recurrence after arthroscopic stabilization (odds ratio, 4.21; 95% CI, 2.16-8.21). Moreover, patients presenting for arthroscopic Bankart repair with GBL ≥15% had nearly 3-times greater odds of recurrent instability. CONCLUSION: GBL ≥15% in an active patient population portends to increased odds of recurrent instability events and inferior clinical outcomes after arthroscopic Bankart repair. Furthermore, nonmodifiable risk factors, such as age (<20 years) and duration of symptoms before presentation (>5 months), significantly affect risk of recurrence and should be key factors when counseling patients on risk of failure and determining the ideal procedure for the individual patient.

Management of the Failed Latarjet Procedure: Outcomes of Revision Surgery With Fresh Distal Tibial Allograft.

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.

Tibial Slope and Its Effect on Graft Force in Posterior Cruciate Ligament Reconstructions.

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.

Fibular Collateral Ligament/ Posterolateral Corner Injury: When to Repair, Reconstruct, or Both.

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.

A Prospective Analysis of Patients With Anterior Versus Posterior Shoulder Instability: A Matched Cohort Examination and Surgical Outcome Analysis of 200 Patients.

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.

Decreased Posterior Tibial Slope Does Not Affect Postoperative Posterior Knee Laxity After Double-Bundle Posterior Cruciate Ligament Reconstruction.

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.

Posterior Tibial Slope and Risk of Posterior Cruciate Ligament Injury.

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.

Tibial Slope and Its Effect on Force in Anterior Cruciate Ligament Grafts: Anterior Cruciate Ligament Force Increases Linearly as Posterior Tibial Slope Increases.

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.

Proximal Tibiofibular Reconstruction in Adolescent Patients.

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.

Surgical Repair of Dynamic Snapping Biceps Femoris Tendon.

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.

Blood Flow Restriction Therapy After Knee Surgery: Indications, Safety Considerations, and Postoperative Protocol.

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.

The Role of Blood Flow Restriction Therapy Following Knee Surgery: Expert Opinion.

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.

Biomechanical Comparison of Screw Fixation Versus a Cortical Button and Self-tensioning Suture for the Latarjet Procedure.

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.

The Epidemiology of Ankle Injuries Identified at the National Football League Combine, 2009-2015.

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.

Changes in the Neurovascular Anatomy of the Shoulder After an Open Latarjet Procedure: Defining a Surgical Safe Zone.

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.

Unilateral Dislocation of the Posterior Tibialis Tendon (PTT) and Flexor Digitorum Longus Tendon With Contralateral PTT Subluxation in a Patient With Congenitally Shallow Flexor Groove.

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.

Hip Arthroscopy for Femoroacetabular Impingement in a Military Population.

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.

Classification and Analysis of Attritional Glenoid Bone Loss in Recurrent Anterior Shoulder Instability.

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 (<34%), moderate (34% to <67%), and severe (≥67%) attritional loss groups. Clinical history and demographics were correlated to ABL, and GBL and ABL were compared. 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.

The effect of a combined glenoid and Hill-Sachs defect on glenohumeral stability: a biomechanical cadaveric study using 3-dimensional modeling of 142 patients.

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 cm(3); small) and 50th percentile (1.47 cm(3); 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.