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Stress radiographs can provide an objective, quantifiable assessment of ligamentous knee injury. Commonly utilized techniques include varus, valgus, and posterior stress radiographs and can be used to augment findings on physical examination and magnetic resonance imaging. Both in vitro and in vivo studies have demonstrated reliability and validity of stress radiographs for diagnosing isolated and multiple ligament knee injuries. Varus stress radiographs are clinician applied at 20° flexion to detect injuries to the fibular collateral ligament and posterolateral corner. Valgus stress radiographs are clinician applied at 20° flexion to detect injuries to the medial collateral ligament or posteromedial corner. To evaluate the posterior cruciate ligament, posterior kneeling stress radiographs are obtained with the patient kneeling at 90° flexion on a firm platform. Bilateral radiographs are obtained and the side-to-side difference is compared to established criteria for injury severity. Stress radiographs support accurate diagnosis of complex knee injuries and also provide an objective measure of knee stability following ligament reconstruction. These imaging techniques can be performed in an ambulatory clinic setting with minimal additional equipment, and are thereby cost-effective, efficient, and support clinical decision-making in the treatment of complex knee injuries.

The purpose of this study is to evaluate the clinical outcomes and revision rates of skeletally mature patients aged 25 years or younger who have undergone either BPTB autograft or deep-frozen, non-irradiated BPTB allograft ACL reconstruction by a single surgeon. Two hundred and twenty-four patients aged 25 or younger at the time of surgery were identified as having a transtibial ACL reconstruction with either a BPTB autograft or deep-frozen, non-irradiated BPTB allograft by one senior surgeon (101 autografts vs. 123 allografts) over the study time period. Primary outcome measure included the need for ACL revision. One hundred and nineteen patients with at least 2-year clinical follow-up agreed to participate in secondary outcome measurement arm of the study and were administered the Lysholm Knee Scoring Scale and IKDC Subjective Knee Evaluation Form. The median Lysholm scores were 95 (40–100) and 95 (68–100) and the median IKDC scores were 95.4 (54.0–100) and 95.4 (72.4–100) in the allograft and autograft groups, respectively. The differences in the Lysholm scores and the IKDC scores were not statistically significant (P = n.s.). There were 13 patients requiring ACL revision, 12 allograft versus one autograft (P = 0.005). Although there is no significant difference in patient-rated outcome between ACL reconstructions using BPTB autografts versus BPTB allografts, a significantly higher rate of ACL revision was found in allograft patients. The results of our study support a growing body of literature that BPTB autograft reconstruction leads to lower retear rates in younger individuals, an important factor in the graft selection process for these patients. III.

Purpose To evaluate the diagnostic accuracy of magnetic resonance imaging and varus stress radiographs for fibular collateral ligament (FCL) tears, and compare these modalities to intraoperative findings. Methods All patients who underwent an isolated FCL or combined anterior cruciate ligament (ACL)/FCL reconstruction by a single surgeon between 2010 and 2017 with preoperative varus stress radiographs and magnetic resonance imaging (MRI) were included in this study. A control group was composed of patients with an MRI and intact ACL and FCL. Sensitivity and specificity of diagnosing FCL injuries on MRI were determined based on review by a fellowship-trained musculoskeletal radiologist, blinded to the pathology associated with each patient (FCL injury vs control), and compared with the gold standard of examination under anesthesia, followed by surgical confirmation of an FCL tear at the time of FCL reconstruction. The sensitivity of diagnosing an FCL injury based on varus stress radiographs was also determined. Furthermore, the ability of both imaging modalities to identify an FCL injury was stratified based on acute versus chronic etiology. Results A total of 232 patients were included: 98 patients in the FCL tear group (mean age: 33.6 ± 12.2 years) and 134 patients in the control group (mean age: 44.0 ± 17.2 years). Varus stress radiographs were determined to be more sensitive in diagnosing FCL injuries compared with MRI, with an overall sensitivity of 70% compared with 66%, respectively. Based on MRI, overall specificity was 68%. Based on chronicity of the injuries, MRI was more accurate for detecting acute FCL injuries than chronic injuries ( P = .002), and varus stress radiographs were more accurate for detecting chronic FCL injuries than acute injuries ( P = .041). Conclusions The results support the use of both varus stress radiographs and MRI in diagnosing FCL injuries, because MRI is more sensitive in diagnosing an acute FCL tear, and varus stress radiographs are more sensitive in diagnosing a chronic FCL tear. Both imaging modalities are recommended to diagnose both acute and chronic FCL injuries. Level of Evidence Level II, case-control study.

Background: Fibular collateral ligament (FCL) tears are challenging to diagnose. Left untreated, FCL tears lead to residual ligament instability and increased joint loading on the medial compartment of the knee. Additionally, when a concomitant anterior cruciate ligament (ACL) reconstruction is performed, increased forces on reconstruction grafts occur, which may lead to premature graft failure. Stress radiographs constitute a reliable and validated technique for the objective assessment of a complete grade III FCL tear. Purpose: To evaluate side-to-side difference (SSD) values of lateral compartment gapping on varus stress radiographs in patients with a grade III injury to the FCL. Additionally, to evaluate the reliability and reproducibility of 3 different measurement techniques that used various radiographic reference points. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Inclusion criteria were patients who sustained an FCL with or without a concomitant ACL injury and underwent a combined FCL + ACL reconstruction between 2010 and 2016. Patients were excluded if they had a complete posterolateral corner injury, open physes, intra-articular fracture, meniscal root tear, other ligament injury, or prior surgery on either knee. All FCL tears were diagnosed with a clinical varus stress examination at 0° and 20° of knee flexion and varus stress radiographs at 20° of knee flexion measured in 3 different locations. The SSD for lateral compartment gapping was obtained from the varus stress radiographs and then statistically compared for interrater and intrarater reliability. Results: A total of 98 consecutive patients (50 males, 48 females; 13 isolated FCL injuries, 85 combined ACL + FCL injuries) with mean age 33.6 years (range, 18-69 years) were included. Measurement techniques 1, 2, and 3 had mean ± SD lateral compartment SSDs of 2.4 ± 0.20 mm, 2.2 ± 0.20 mm, and 2.0 ± 0.03 mm, respectively (no significant differences). Interrater reliabilities for the 3 measuring techniques were 0.83, 0.86, and 0.91, respectively, while intrarater reliabilities were 0.99, 0.77, and 0.99, respectively. Conclusion: This study demonstrated a lower SSD value of 2.2 mm to be consistent with a grade III FCL tear on clinician-applied varus stress radiographs in the clinical setting. Although all SSD measurement locations had excellent reliability, the method using the midpoint of the lateral tibial plateau was found to be the most reproducible.