Editorial Commentary: Diminished Hip Hypoplastic Labrum Predicts Poor Patient Outcomes After Non-augmented Primary Repair.

Diminished hip labral size and tissue quality may be a predictor of poor patient outcomes when a non-augmented primary labral repair is performed. Labral augmentation is an option for patients with hypoplastic or degenerative labral tissue. The optimal graft for augmentation has yet to be identified, and biomechanical research shows no difference in force to suction-seal disruption between dermal allograft and iliotibial band allograft when used to augment the labrum. However, time-zero biomechanical studies do not reflect the biological ability of the graft to heal to surrounding structures, revascularization of the graft, durability of the graft, hip capsular status, and response to functional demands of the patient.

Bulk Osteochondral Allograft for a Firearm Injury to the Medial Femoral Condyle in a Military Service Member: A Case Report.

A 27-year-old U.S. military active duty male sustained an accidental, self-inflicted left knee gunshot injury with an unsalvageable medial femoral condyle injury. The patient underwent bulk osteochondral allograft transplantation. Nine months post-operation, the patient was fit for full military duties with no reported functional limitations and remained on active duty. Severe knee medial femoral condyle bone loss after accidental firearm injury is uncommon. Bulk knee osteochondral allograft transplantation to the medial femoral condyle provided a successful treatment option for an active duty U.S. military member with multicompartment osteochondral defects and severe medial femoral condyle bone loss due to a gunshot injury.

Bilateral Knee Dislocations in an Active Duty Service Member: A Case Report.

This case highlights a staged operative approach for a patient who sustained bilateral knee dislocations and subsequent staged operative treatment and rehabilitation. This patient underwent bilateral multiligamentous knee reconstructions and left-sided peroneal nerve allografting because of complete peroneal nerve palsy. The initial treatment was bilateral medial collateral ligament reconstructions, posterolateral corner reconstructions, and capsular repairs with left leg peroneal nerve allografting and repair of avulsed biceps femoris tendon. The patient underwent physical therapy following the first stage procedure until he regained appropriate motion and soft tissue healing occurred. Subsequently, combined anterior cruciate and posterior cruciate ligament reconstructions were performed in a staged fashion to allow one leg to fully bear weight for rehabilitation purposes. With the help of a multidisciplinary surgical and rehabilitation team, the patient has regained the stability of his knees and achieved acceptable functional outcomes. A staged systematic approach to multiligamentous bilateral knee reconstruction can provide optimal pain management, obtain initial joint stability, minimize complications, and achieve acceptable functional outcomes. Surgical techniques to first restore medial and lateral structures can be utilized to provide initial valgus and varus stability while allowing for knee mobilization and, eventually, in-line ambulation, before staged anterior and posterior cruciate ligament reconstructions. This case demonstrates a multistaged approach to bilateral knee dislocations with favorable outcomes in a 23-year-old active duty patient.

The Military Orthopedics Tracking Injuries and Outcomes Network: A Solution for Improving Musculoskeletal Care in the Military Health System.

INTRODUCTION: Musculoskeletal injuries are an endemic amongst U.S. Military Service Members and significantly strain the Department of Defense's Military Health System. The Military Health System aims to provide Service Members, military retirees, and their families the right care at the right time. The Military Orthopedics Tracking Injuries and Outcomes Network (MOTION) captures the data that can optimize musculoskeletal care within the Military Health System. This report provides MOTION structural framework and highlights how it can be used to optimize musculoskeletal care. MATERIALS AND METHODS: MOTION established an internet-based data capture system, the MOTION Musculoskeletal Data Portal. All adult Military Health System patients who undergo orthopedic surgery are eligible for entry into the database. All data are collected as routine standard of care, with patients and orthopedic surgeons inputting validated global and condition-specific patient reported outcomes and operative case data, respectively. Patients have the option to consent to allow their standard of care data to be utilized within an institutional review board approved observational research study. MOTION data can be merged with other existing data systems (e.g., electronic medical record) to develop a comprehensive dataset of relevant information. In pursuit of enhancing musculoskeletal injury patient outcomes MOTION aims to: (1) identify factors which predict favorable outcomes; (2) develop models which inform the surgeon and military commanders if patients are behind, on, or ahead of schedule for their targeted return-to-duty/activity; and (3) develop predictive models to better inform patients and surgeons of the likelihood of a positive outcome for various treatment options to enhance patient counseling and expectation management. RESULTS: This is a protocol article describing the intent and methodology for MOTION; thus, to date, there are no results to report. CONCLUSIONS: MOTION was established to capture the data that are necessary to improve military medical readiness and optimize medical resource utilization through the systematic evaluation of short- and long-term musculoskeletal injury patient outcomes. The systematic enhancement of musculoskeletal injury care through data analyses aligns with the National Defense Authorization Act (2017) and Defense Health Agency's Quadruple Aim, which emphasizes optimizing healthcare delivery and Service Member medical readiness. This transformative approach to musculoskeletal care can be applied across disciplines within the Military Health System.

Incorporation of Whipstitch Suture in Tibial Interference Fixation Improves Pullout in Anterior Cruciate Ligament Soft Tissue Grafts.

INTRODUCTION: Interference screw fixation of soft tissue grafts is commonly used in anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to determine whether including suture material at the graft-screw interface affects ultimate fixation strength of soft tissue grafts using a tibialis anterior tendon allograft model. MATERIALS AND METHODS: Forty fresh-frozen human tibialis anterior tendon allografts were fixed to rigid polyurethane foam simulating the tibial tunnel. Twenty grafts underwent fixation with interference screws and 20 with interference bolts. Within each group, 10 grafts had suture in contact with either the screw or bolt. A load-to-failure test was then performed at a rate of 200 mm/min. RESULTS: The group of allografts with sutures in the tibial tunnel had significantly higher load to failure than the group without sutures. Using interference screw fixation, failure load of the grafts without sutures in the tunnel (535.2 ± 73.40 N) was significantly lower (P = .001) than with sutures in the tunnel (696.3 ± 110.0 N). Using interference bolt fixation, failure load of the grafts without sutures in the tunnel (613.0 ± 83.46 N) was significantly lower (P <.0001) than with sutures in the tunnel (845.8 ± 87.23 N). CONCLUSIONS: In a biomechanical model, suture within the tibial tunnel enhances fixation strength with both interference screw and bolt fixation for soft tissue tibialis anterior allografts. Additionally, there was no difference in load to failure when comparing failure of a screw with suture in the tunnel with an interference bolt without suture. Due to improved biomechanical properties, incorporation of suture in the bone-graft interface should be considered when performing soft tissue ACL allograft reconstructions. Failure at the tibial bone-graft interface is a known complication of ACL reconstruction, and incorporation of suture within the interface should be considered for improved biomechanical properties.

Editorial Commentary: Vancomycin Solution Pretreatment of Anterior Cruciate Ligament Tendon Graft Reduces Infection Rates, Is Clinically and Biomechanically Sound, and Is Cost-Effective.

Prevention of postoperative infection following anterior cruciate ligament (ACL) reconstruction remains a high priority for orthopaedic surgeons. Vancomycin presoaking of ACL grafts is a biomechanically sound, clinically effective, and cost-efficient method of improving ACL reconstruction infection rates.

A High-Sensitivity International Knee Documentation Committee Survey Index From the PROMIS System: The Next-Generation Patient-Reported Outcome for a Knee Injury Population.

BACKGROUND: Patient-reported outcomes (PROs) measure progression and quality of care. While legacy PROs such as the International Knee Documentation Committee (IKDC) survey are well-validated, a lengthy PRO creates a time burden on patients, decreasing adherence. In recent years, PROs such as the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function and Pain Interference surveys were developed as computer adaptive tests, reducing time to completion. Previous studies have examined correlation between legacy PROs and PROMIS; however, no studies have developed effective prediction models utilizing PROMIS to create an IKDC index. While the IKDC is the standard knee PRO, computer adaptive PROs offer numerous practical advantages. PURPOSE: To develop a nonlinear predictive model utilizing PROMIS Physical Function and Pain Interference to estimate IKDC survey scores and examine algorithm sensitivity and validity. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 3. METHODS: The MOTION (Military Orthopaedics Tracking Injuries and Outcomes Network) database is a prospectively collected repository of PROs and intraoperative variables. Patients undergoing knee surgery completed the IKDC and PROMIS surveys at varying time points. Nonlinear multivariable predictive models using Gaussian and beta distributions were created to establish an IKDC index score, which was then validated using leave-one-out techniques and minimal clinically important difference analysis. RESULTS: A total of 1011 patients completed the IKDC and PROMIS Physical Function and Pain Interference, providing 1618 complete observations. The algorithms for the Gaussian and beta distribution were validated to predict the IKDC (Pearson = 0.84-0.86; R2 = 0.71-0.74; root mean square error = 9.3-10.0). CONCLUSION: The publicly available predictive models can approximate the IKDC score. The results can be used to compare PROMIS Physical Function and Pain Interference against historical IKDC scores by creating an IKDC index score. Serial use of the IKDC index allows for a lower minimal clinically important difference than the conventional IKDC. PROMIS can be substituted to reduce patient burden, increase completion rates, and produce orthopaedic-specific survey analogs.

Aspirin for Deep-Venous Thrombosis Prophylaxis After Anterior Cruciate Ligament Reconstruction.

AIM: To evaluate whether a daily full-dose aspirin regimen after anterior cruciate ligament (ACL) reconstruction reduces the risk of postoperative symptomatic deep-venous thrombosis (DVT). MATERIALS AND METHODS: Single-center retrospective cohort study of patients who underwent ACL reconstruction from 2007 to 2016. One thousand two hundred thirty-three patients met inclusion criteria: 821 patients received no chemoprophylaxis and 412 patients received daily full-dose aspirin. RESULTS: A total of 10 patients, seven receiving no chemoprophylaxis and three using aspirin, sustained a postoperative symptomatic DVT. Calculated adjusted odds ratio for symptomatic postoperative DVT for aspirin versus no chemoprophylaxis was 0.928 (95% CI 0.237-3.629, P value = 0.91). Odds ratio for symptomatic postoperative DVT occurrence among tobacco users versus non-tobacco users was 3.76 (95% CI 1.077-13.124, P = 0.04). CONCLUSIONS: No statistically significant difference was observed in postoperative symptomatic DVT after ACL reconstruction in those who received full-dose aspirin chemoprophylaxis versus those with no chemoprophylaxis. Additionally, there was a significantly increased risk of postoperative symptomatic DVT with tobacco use.

Generating the American Shoulder and Elbow Surgeons Score Using Multivariable Predictive Models and Computer Adaptive Testing to Reduce Survey Burden.

BACKGROUND: The preferred patient-reported outcome measure for the assessment of shoulder conditions continues to evolve. Previous studies correlating the Patient-Reported Outcomes Measurement Information System (PROMIS) computer adaptive tests (CATs) to the American Shoulder and Elbow Surgeons (ASES) score have focused on a singular domain (pain or physical function) but have not evaluated the combined domains of pain and physical function that compose the ASES score. Additionally, previous studies have not provided a multivariable prediction tool to convert PROMIS scores to more familiar legacy scores. PURPOSE: To establish a valid predictive model of ASES scores using a nonlinear combination of PROMIS domains for physical function and pain. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 3. METHODS: The Military Orthopaedics Tracking Injuries and Outcomes Network (MOTION) database is a prospectively collected repository of patient-reported outcomes and intraoperative variables. Patients in MOTION research who underwent shoulder surgery and completed the ASES, PROMIS Physical Function, and PROMIS Pain Interference at varying time points were included in the present analysis. Nonlinear multivariable predictive models were created to establish an ASES index score and then validated using "leave 1 out" techniques and minimal clinically important difference /substantial clinical benefit (MCID/SCB) analysis. RESULTS: A total of 909 patients completed the ASES, PROMIS Physical Function, and PROMIS Pain Interference at presurgery, 6 weeks, 6 months, and 1 year after surgery, providing 1502 complete observations. The PROMIS CAT predictive model was strongly validated to predict the ASES (Pearson coefficient = 0.76-0.78; R2 = 0.57-0.62; root mean square error = 13.3-14.1). The MCID/SCB for the ASES was 21.7, and the best ASES index MCID/SCB was 19.4, suggesting that the derived ASES index is effective and can reliably re-create ASES scores. CONCLUSION: The PROMIS CAT predictive models are able to approximate the ASES score within 13 to 14 points, which is 7 points more accurate than the ASES MCID/SCB derived from the sample. Our ASES index algorithm, which is freely available online (https://osf.io/ctmnd/), has a lower MCID/SCB than the ASES itself. This algorithm can be used to decrease patient survey burden by 11 questions and provide a reliable ASES analog to clinicians.

Extravasation of fluid in arthroscopic shoulder surgery requiring prolonged intubation: a case report.

BACKGROUND: Shoulder arthroscopy is a safe and effective procedure with a low complication rate. Although rare, there are potentially life-threatening risks such as fluid extravasation causing airway compromise. CASE PRESENTATION: We report the case of a 65-year-old female treated with an arthroscopic rotator cuff repair who had significant extravasation of arthroscopic fluid causing severe facial and neck swelling. Overnight intubation was required for respiratory monitoring until the edema had resolved enough to allow safe extubation. CONCLUSION: This case highlights the risk factors and clinical course of a patient with airway compromise caused by extravasation of fluid during shoulder arthroscopy. Although shoulder arthroscopy is a safe procedure, surgeon familiarity with the risk factors for this complication and close monitoring can aid in its identification and allow for appropriate treatment.

Biceps Tenodesis and Intra-articular Decompression for Treatment of Superior Labral Tear from Anterior to Posterior and Associated Paralabral Cyst in Active Duty Military.

Background: To examine the outcomes of combined biceps tenodesis and indirect, intra-articular arthroscopic paralabral cyst decompression for the treatment of active duty military patients with superior labral from anterior to posterior tears and associated paralabral cysts. Methods: Retrospective chart review of all active duty patients at our institution from 2011 to 2014 with superior labral from anterior to posterior tears and associated paralabral cysts at the spinoglenoid notch treated with biceps tenodesis and indirect arthroscopic cyst decompression. Patient charts were examined for pre- and post-operative parameters including strength, range of motion, visual analog scale pain score, American Shoulder and Elbow Surgeon Score, and Single Assessment Numeric Evaluation Score. Results: Seven patients met study criteria. All patients presented with chronic shoulder pain and decreased external rotation strength, and three patients had clinically apparent muscular atrophy. Pre- and post-operative assessment showed external rotation strength increased from a median of 4 (range 4-4) to 5 (range 4-5; p-value = 0.014), Single Assessment Numeric Evaluation increased from a median of 50 (range 0-70) to 75 (range 30-95; p-value = 0.031), American Shoulder and Elbow Surgeon increased from a median of 46.0 (range 32.0-58.0) to 66.5 (range 58.0-98.0; p-value = 0.068), and visual analog scale pain score decreased from a median of 3 (range 1-8) to 0 (range 0-5; p-value = 0.017). Median follow-up was 66 wk (range 36-138 wk). The change was statistically significant (p <0.05) for external rotation strength, Single Assessment Numeric Evaluation, and VAS reduction. Post-operatively, all patients returned to full duty at a median of 20 wk (range 12-36 wk). Conclusion: The use of biceps tenodesis in conjunction with indirect, intra-articular arthroscopic paralabral cyst decompression is an effective technique in an active patient population with superior labral from anterior to posterior tear with associated paralabral cyst.

Contact Dermatitis Reaction to 2-Octyl Cyanoacrylate Following 3 Orthopedic Procedures.

Two-octyl cyanoacrylate is a popular skin adhesive used for closing surgical incisions. Since Food and Drug Administration approval in 1998, the few reports of adverse reactions following its use have primarily been limited to the nonorthopedic literature. The authors present a case series of contact dermatitis associated with 2-octyl cyanoacrylate following orthopedic surgery and a review of the literature on the diagnosis and treatment of this complication. All 3 patients presented with blistering around their incisions within 2 weeks of surgery and responded to treatment involving removal of the offending agent and use of oral diphenhydramine and hydroxyzine and topical triamcinolone. One case was complicated by a draining hematoma, requiring irrigation and debridement. Complete resolution occurred in all cases. This case series is intended to increase awareness in the orthopedic community of allergic contact dermatitis to 2-octyl cyanoacrylate and its appropriate treatment. [Orthopedics. 2018; 41(2):e289-e291.].

Passive Anterior Tibial Subluxation in the Setting of Anterior Cruciate Ligament Injuries: A Comparative Analysis of Ligament-Deficient States.

BACKGROUND: Static anterior tibial subluxation after an anterior cruciate ligament (ACL) injury highlights the abnormal relationship between the tibia and femur in patients with ACL insufficiency, although causal factors including injuries to secondary stabilizers or the time from injury to reconstruction have not been examined. PURPOSE: To determine static relationships between the tibia and femur in patients with various states of ACL deficiency and to identify factors associated with anterior tibial subluxation. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Patients treated for ACL injuries were identified from an institutional registry and assigned to 1 of 4 cohorts: intact ACL, acute ACL disruption, chronic ACL disruption, and failed ACL reconstruction (ACLR). Anterior tibial subluxation of the medial and lateral compartments relative to the femoral condyles were measured on magnetic resonance imaging (MRI), and an MRI evaluation for meniscal tears, chondral defects, and injuries to the anterolateral ligament (ALL) was performed. RESULTS: One hundred eighty-six ACL-insufficient knees met inclusion criteria, with 26 patients without an ACL injury utilized as a control group. In the lateral compartment, the mean anterior tibial subluxation measured 0.78 mm for the control group (n = 26), 2.81 mm for the acute ACL injury group (n = 74), 3.64 mm for the chronic ACL injury group (n = 40), and 4.91 mm for the failed ACLR group (n = 72). In the failed ACLR group, 37.5% of patients demonstrated lateral compartment anterior subluxation ≥6 mm, and 11.1% of this group had anterior subluxation of the lateral compartment ≥10 mm. Multivariate regression revealed that the presence of both medial and lateral chondral defects was associated with a mean 1.09-mm increase in subluxation of the medial compartment ( P = .013). The combination of medial and lateral meniscal tears was an independent predictor of increased lateral tibia subluxation by 1.611 mm ( P = .0022). Additionally, across all knee states, an injury to the ALL was associated with increased anterior tibial subluxation in both the medial compartment ( P = .0438) and lateral compartment ( P = .0046). In 29.4% of knees with ALL injuries, lateral tibial subluxation was ≥6 mm, but with multivariate regression analysis, an ALL injury was not an independent predictor of anterior subluxation of the lateral compartment. CONCLUSION: Knees with failed ACLR are associated with more anterior tibial subluxation than those with primary ACL deficiency. Using previously reported thresholds of 6 to 10 mm of lateral compartment subluxation for a positive pivot shift, between 11.1% and 37.5% of knees with failed ACLR may be in a "resting pivoted position." In primary ACL-deficient knees, anterior tibial subluxation is associated with chondral injuries and meniscal tears but not injury chronicity.

Epidemiology and Outcomes of Lisfranc Injuries Identified at the National Football League Scouting Combine.

BACKGROUND: Lisfranc injuries are challenging to treat and may have a detrimental effect on athletic performance. PURPOSE: (1) Determine the epidemiological characteristics of Lisfranc injuries at the annual National Football League (NFL) Scouting Combine, (2) define player positions at risk for these injuries, and (3) evaluate the impact that these injuries and radiographic findings have on NFL draft position and performance. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All players who sustained a Lisfranc injury prior to Combine evaluation between 2009 and 2015 were evaluated. The epidemiological characteristics, player positions affected, treatment methods, and number of missed collegiate games were recorded. Radiographic outcomes were analyzed via Combine radiograph findings, while NFL performance outcomes were assessed for all Lisfranc injuries (2009-2013) compared with matched controls in the first 2 years of play. RESULTS: A total of 41 of 2162 (1.8%) Combine participants were identified with Lisfranc injuries, of whom 26 of 41 (63.4%) were managed operatively. Players who underwent surgery were more likely to go undrafted compared with players managed nonoperatively (38.5% vs 13.3%, operative vs nonoperative management, respectively; P = .04) and featured a worse NFL draft pick position (155.6 vs 109; P = .03). Lisfranc-injured players when compared with controls were noted to have worse outcomes in terms of NFL draft position (142 vs 111.3, Lisfranc-injured players vs controls, respectively; P = .04), NFL career length 2 years or longer (62.5% vs 69.6%; P = .23), and number of games played (16.9 vs 23.3; P = .001) and started (6.8 vs 10.5; P = .08) within the first 2 years of their NFL career. Radiographs demonstrated that 17 of 41 (41.5%) athletes had residual Lisfranc joint displacement greater than 2 mm compared with the contralateral foot. Lisfranc-injured athletes with greater than 2 mm residual displacement, when compared with matched controls, had worse draft position (156.9 vs 111.2 for Lisfranc-injured players vs controls, respectively; P = .009) and fewer games played (14.4 vs 23.3; P = .001) and started (3.1 vs 10.5; P = .03). Moreover, athletes with greater than 2 mm residual displacement featured worse outcomes across all assessed NFL variables versus athletes with residual displacement of 2 mm or less. CONCLUSION: Lisfranc injuries identified at the NFL Combine have an adverse effect on an NFL athlete's draft status, draft position, and overall play during initial NFL seasons. In particular, residual displacement of the Lisfranc joint has a detrimental effect on the first 2 seasons of NFL play and may lead to long-lasting negative effects on the athlete's career.

Surgical Release of the Pectoralis Minor Tendon for Scapular Dyskinesia and Shoulder Pain.

BACKGROUND: Pectoralis minor (PM) tightness has been linked to pain and dysfunction of the shoulder joint secondary to anterior tilt and internal rotation of the scapula, thus causing secondary impingement of the subacromial space. PURPOSE: To describe outcomes pertaining to nonoperative and operative treatment via surgical release of the PM tendon for pathologic PM tightness in an active population. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Over a 3-year period, a total of 46 patients were enrolled (mean age, 25.5 years; range, 18-33 years). Inclusion criteria consisted of symptomatic shoulder pain, limited range of overhead motion, inability to participate in overhead lifting activities, and examination findings consistent with scapular dysfunction secondary to a tight PM with tenderness to palpation of the PM tendon. All patients underwent a lengthy physical therapy and stretching program (mean, 11.4 months; range, 3-23 months), which was followed by serial examinations for resolution of symptoms and scapular tilt. Of the 46 patients, 6 (13%) were unable to adequately stretch the PM and underwent isolated mini-open PM release. Outcomes were assessed with scapula protraction measurements and pain scales as well as American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation (SANE), and visual analog scale (VAS) scores. RESULTS: Forty of the 46 patients (87%) resolved the tight PM and scapular-mediated symptoms with a dedicated therapy program (pre- and posttreatment mean outcome scores: 58 and 91 [ASES], 50 and 90 [SANE], 4.9 and 0.8 [VAS]; P < .01 for all), but 6 patients were considered nonresponders (mean score, 48 [ASES], 40 [SANE], 5.9 [VAS]) and elected to have surgical PM release, with improved scores in all domains (mean score, 89 [ASES], 90.4 [SANE], 0.9 [VAS]; P < .01) at final follow-up of 26 months (range, 25-30 months). Additionally, protraction of the scapula improved from 1.2 to 0.3 cm in a mean midline measurement from the chest wall preoperatively to postoperatively ( P < .01), similar to results in nonoperative responders. No surgical complications were reported, and all patients returned to full activities. CONCLUSION: In most patients, PM tightness can be successfully treated with a nonoperative focused PM stretching program. However, in refractory and pathologically tight PM cases, this series demonstrates predictable return to function with notable improvement in shoulder symptoms after surgical release of the PM. Additional research is necessary to evaluate the long-term efficacy of isolated PM treatment.

Surgical management of acute claw hand in a competitive baseball player.

We describe an unusual case of acute ulnar neuropathy with a flexible claw hand deformity in a baseball pitcher. Treatment involved ulnar nerve decompression at the elbow with subsequent recurrence of symptoms upon return to pitching. Definitive treatment included a wide secondary release of tethered locations resulting in return of function. At final follow-up the patient has returned to unrestricted baseball throwing activities.

Validation of varus stress radiographs for anterior cruciate ligament and posterolateral corner knee injuries: A biomechanical study.

PURPOSE: The purpose of this study was to determine the effect of isolated anterior cruciate ligament (ACL) insufficiency on the radiographic varus stress test, and to provide reference data for the increase in lateral compartment opening under varus stress for a combined ACL and PLC injury. METHODS: Ten cadaveric lower extremities were fixed to a jig in 20° of knee flexion. Twelve Newton-meter (Nm) and clinician-applied varus loads were tested, first with intact knee ligaments, followed by sequential sectioning of the ACL, fibular collateral ligament (FCL), popliteus tendon and the popliteofibular ligament (PFL). Lateral compartment opening was measured after each sequential sectioning. RESULTS: Maximum increase in lateral compartment opening for an isolated ACL deficient knee was 1.06mm with mean increase of 0.52mm (p=0.021) for the clinician-applied load. Mean increase in lateral compartment opening in an ACL and FCL deficient knee compared to the intact knee was 1.48mm (p<0.005) and 1.99mm (p<0.005) for the 12-Nm and clinician-applied loads, respectively, increasing to 1.94mm (p<0.005) and 2.68mm (p<0.005) with sectioning of the ACL and all PLC structures. CONCLUSIONS: Anterior cruciate ligament deficiency contributes to lateral compartment opening on varus stress radiographs though not sufficiently to confound previously established standards for lateral ligament knee injuries. We did not demonstrate the same magnitude of lateral compartment opening with sectioning of the PLC structures as previously reported, questioning the reproducibility of varus stress radiographic testing among institutions. Clinicians are cautioned against making surgical decisions based solely on current standards for radiographic stress examinations.

ACL Deficiency Increases Forces on the Medial Femoral Condyle and the Lateral Meniscus with Applied Rotatory Loads.

BACKGROUND: The articular surfaces and menisci act with the anterior cruciate ligament (ACL) to stabilize the knee joint. Their role in resisting applied rotatory loads characteristic of instability events is unclear despite commonly observed damage to these intra-articular structures in the acute and chronic ACL injury settings. METHODS: Ten fresh-frozen human cadaveric knees were mounted to a robotic manipulator. Combined valgus and internal rotation torques were applied in the presence and absence of a 300-N compressive load. Forces carried by the individual menisci and via cartilage-to-cartilage contact on each femoral condyle in ACL-intact and ACL-sectioned states were measured using the principle of superposition. RESULTS: In response to applied valgus and internal rotation torques in the absence of compression, sectioning of the ACL increased the net force carried by the lateral meniscus by at most 65.8 N (p < 0.001). Moreover, the anterior shear force carried by the lateral meniscus increased by 25.7 N (p < 0.001) and 36.5 N (p = 0.042) in the absence and presence of compression, respectively. In response to applied valgus and internal rotation torques, sectioning of the ACL increased the net force carried by cartilage-to-cartilage contact on the medial femoral condyle by at most 38.9 N (p = 0.006) and 46.7 N (p = 0.040) in the absence and presence of compression, respectively. Additionally, the lateral shear force carried by cartilage-to-cartilage contact on the medial femoral condyle increased by at most 21.0 N (p = 0.005) and by 28.0 N (p = 0.025) in the absence and presence of compression, respectively. Forces carried by the medial meniscus and by cartilage-to-cartilage contact on the lateral femoral condyle changed by <5 N as a result of ACL sectioning. CONCLUSIONS: ACL sectioning increased the net forces carried by the lateral meniscus and medial femoral condyle-and the anterior shear and lateral shear forces, respectively-in response to multiplanar valgus and internal rotation torque. CLINICAL RELEVANCE: These loading patterns provide a biomechanical rationale for clinical patterns of intra-articular derangement such as lateral meniscal injury and osseous remodeling of the medial compartment seen with ACL insufficiency.

Double-Row Capsulolabral Repair Increases Load to Failure and Decreases Excessive Motion.

PURPOSE: Using a cadaver shoulder instability model and load-testing device, we compared biomechanical characteristics of double-row and single-row capsulolabral repairs. We hypothesized a greater reduction in glenohumeral motion and translation and a higher load to failure in a mattress double-row capsulolabral repair than in a single-row repair. METHODS: In 6 matched pairs of cadaveric shoulders, a capsulolabral injury was created. One shoulder was repaired with a single-row technique, and the other with a double-row mattress technique. Rotational range of motion, anterior-inferior translation, and humeral head kinematics were measured. Load-to-failure testing measured stiffness, yield load, deformation at yield load, energy absorbed at yield load, load to failure, deformation at ultimate load, and energy absorbed at ultimate load. RESULTS: Double-row repair significantly decreased external rotation and total range of motion compared with single-row repair. Both repairs decreased anterior-inferior translation compared with the capsulolabral-injured condition, however, no differences existed between repair types. Yield load in the single-row group was 171.3 ± 110.1 N, and in the double-row group it was 216.1 ± 83.1 N (P = .02). Ultimate load to failure in the single-row group was 224.5 ± 121.0 N, and in the double-row group it was 373.9 ± 172.0 N (P = .05). Energy absorbed at ultimate load in the single-row group was 1,745.4 ± 1,462.9 N-mm, and in the double-row group it was 4,649.8 ± 1,930.8 N-mm (P = .02). CONCLUSIONS: In cases of capsulolabral disruption, double-row repair techniques may result in decreased shoulder rotational range of motion and improved load-to-failure characteristics. CLINICAL RELEVANCE: In cases of capsulolabral disruption, repair techniques with double-row mattress repair may provide more secure fixation. Double-row capsulolabral repair decreases shoulder motion and increases load to failure, yield load, and energy absorbed at yield load more than single-row repair.