Causal relationships between pain, medical treatments, and knee osteoarthritis: A graphical causal model to guide analyses.

OBJECTIVE: Randomized controlled trials (RCTs) are a gold standard for estimating the benefits of clinical interventions, but their decision-making utility can be limited by relatively short follow-up time. Longer-term follow-up of RCT participants is essential to support treatment decisions. However, as time from randomization accrues, loss to follow-up and competing events can introduce biases and require covariate adjustment even for intention-to-treat effects. We describe a process for synthesizing expert knowledge and apply this to long-term follow-up of an RCT of treatments for meniscal tears in patients with knee osteoarthritis (OA). METHODS: We identified 2 post-randomization events likely to impact accurate assessment of pain outcomes beyond 5 years in trial participants: loss to follow-up and total knee replacement (TKR). We conducted literature searches for covariates related to pain and TKR in individuals with knee OA and combined these with expert input. We synthesized the evidence into graphical models. RESULTS: We identified 94 potential covariates potentially related to pain and/or TKR among individuals with knee OA. Of these, 46 were identified in the literature review and 48 by expert panelists. We determined that adjustment for 50 covariates may be required to estimate the long-term effects of knee OA treatments on pain. CONCLUSION: We present a process for combining literature reviews with expert input to synthesize existing knowledge and improve covariate selection. We apply this process to the long-term follow-up of a randomized trial and show that expert input provides additional information not obtainable from literature reviews alone.

Combined ACL/MCL Injuries: Surgeons Should Have a Low Threshold to Operate on the MCL.

Combined ACL/MCL injuries are relatively common and multiple factors are involved in surgical decision-making, particularly when it comes to the MCL. Historically, most surgeons treated the MCL conservatively, and performed staged MCL reconstruction after MCL reconstruction only if there was persistent medial instability. This was followed by a non-operative approach for the MCL (when reconstructing the ACL) unless there was evidence of extreme (Grade III or > 1 cm) valgus instability, valgus malalignment, or mid-substance or tibial sided injury, avulsion, or Stener lesion. However, the most recent research demonstrates that combined ACL/MCL injuries present a higher risk of ACL reconstruction failure and subsequent revision compared to ACL injuries alone. With growing biomechanical and clinical evidence, more surgeons are repairing or reconstructing the MCL in these combined injuries. Although there is no clear consensus, we recommend surgeons consider surgically treating the MCL to avoid not only excessive force on the ACL graft but also persistent valgus laxity, which can lead to ACL failure. For distal MCL avulsions, repairs have shown excellent midterm outcomes, especially if the tissue quality is pristine. If the tissue quality is not repairable, then we would advocate for repairing whatever tissue is repairable and augmenting with an MCL reconstruction. For mid substance MCL injuries, if surgical intervention is required, we advocate for MCL reconstruction. For proximal tears, the same criteria used for distal tears apply with management based on tissue quality and joint stability after repair. The ACL is a secondary stabilizer to valgus loads, and MCL deficiency results in tremendous strain on ACL graft reconstructions. If the MCL is even mildly incompetent, we strongly advocate for treating the MCL surgically in this setting.

Editorial Commentary: Clinical and Basic Science Evidence Supports the Use of Suture Tape Augmentation of Posterior Cruciate Ligament Reconstruction.

Although isolated posterior cruciate ligament (PCL) injuries often can be treated successfully without surgical intervention, in the setting of persistent instability or multiligamentous knee injury, PCL reconstruction is indicated. PCL reconstructions often have resulted in persistent postoperative laxity. Recent research suggests there may be a role for suture tape-augmented grafts, which have demonstrated decreased clinical and radiographic laxity as well as improved rates of return to previous level of activity, as compared with PCL reconstruction alone. Several biomechanical studies also have supported the use of suture tape augmentation in PCL reconstruction, and the use of suture tape augmentation or internal bracing and ligament surgery is gaining widespread popularity. These ultrahigh molecular weight polyethylene/polyester suture tapes have been shown to be safe and effective. We may be at the point at which the evidence supports the use of suture tape augmentation of PCL reconstruction.

Editorial Commentary: Gracilis-Sparing Anterior Cruciate Ligament Hamstring Graft Reconstruction Is Less Invasive Than Semitendinosus-Gracilis Graft Harvest, and Shows No Clinical Difference in Outcomes With Grafts Greater Than 8 mm in Diameter.

Although patellar tendon grafts are most commonly used for anterior cruciate ligament reconstruction in the United States, hamstring autograft is most commonly used worldwide. Hamstring advantages include easy, quick harvest; low morbidity; ease of rehabilitation (compared with patellar tendon grafts); and relatively less pain. Historically, both the semitendinosus (ST) and gracilis are harvested, but by doubling, tripling, or quadrupling the ST to achieve an 8-mm graft, the gracilis can be spared, resulting in less knee flexion weakness. However, recent research has shown no clinically important difference between ST and ST-gracilis patient outcomes.

Editorial Commentary: Surgical Videos on YouTube Are Not Peer Reviewed and Have Low Educational Value.

The rise of online platforms like YouTube for health information has prompted scrutiny over the quality of medical/surgical-related video content. Recent research on YouTube videos regarding anterior cruciate ligament reconstruction (ACLR) with quadriceps tendon autograft shows low educational quality and reliability using established assessment tools. Physicians primarily published content, with longer videos, and physician-generated videos, generally correlating with higher quality. However, YouTube's inadequacy as a reliable source for ACLR information underscores the need for alternative educational resources. Orthopaedic health care professionals must play a pivotal role in guiding patients toward credible sources and take aim at improving online content quality. Understanding patient preferences for online resources is essential for enhancing patient education, the patient-provider relationship, and decision-making in orthopaedic care.

Satisfactory Clinical Outcomes and Continuance of Sports After Hip Arthroscopic Labral Repair in Young Competitive Athletes at Minimum 8.5-Year Follow-Up.

PURPOSE: To evaluate long-term patient-reported outcomes and achievement rates of patient acceptable symptomatic state (PASS) in young athletes undergoing hip arthroscopy, and to report long-term sports continuance and reoperation. METHODS: Inclusion criteria consisted of age <24 years at surgery, femoroacetabular impingement undergoing primary hip arthroscopy with labral repair, and participation in sport with intent to return to sport after surgery. The enrollment period was from April 2009 to June 2014. Modified Harris Hip Scores (mHHS), Hip Outcome Score (HOS), HOS Activities of Daily Living (HOS-ADL), and HOS Sport (HOS-Sport) were collected preoperatively, 2 years' postoperatively, and final follow-up. Patients were evaluated for PASS achievement, reoperation, and sports participation. RESULTS: Forty-two hips in 37 patients (11 male, 26 female, age: 17.7 ± 2.1 years, range 13.6-23.0, body mass index 22.8 ± 2.9, range 17.6-33.7) met inclusion criteria and were followed for 10.0 ± 1.3 years (range 8.5-13.0) postoperatively. Mean mHHS, HOS-ADL and HOS-Sports outcome scores at minimum 8.5 years were 82.2 ± 12.9, 89.6 ± 10.9, and 81.8 ± 16.4, respectively, with significant (P < .001) postoperative improvements. Thirty survey respondents (83%) met PASS for mHHS, 27 (75%) for HOS-ADL, and 24 (67%) for HOS-Sports. At minimum 8.5-year follow-up, only 9 of 37 (24%) cited their hip as the reason for stopping sport. Of the remaining patients, 17 of 28 (61%), continued playing their initial sport. There was no difference in patient-reported outcomes between patients who endorsed sports continuance and patients who did not report sports continuance and did not cite their hip as a reason (P ≥ .229). At final follow-up, 4 hips (10%) had undergone subsequent surgical intervention at a mean of 4.8 ± 3.3 years (range 1.0-8.4) postoperatively. CONCLUSIONS: Durable mid-term outcomes and satisfactory PASS achievement rates are observed in young amateur athletes undergoing primary hip arthroscopy. At minimum 8.5-year follow up, approximately 1 in 4 patients discontinue their sports due to hip related reasons. LEVEL OF EVIDENCE: Level IV, case-series.

Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome in Adolescents Improves Outcomes and Clinical Benefit Achievement Rates at Short-Term Follow-Up: A Multicenter Analysis.

PURPOSE: To report minimum 2-year follow-up patient-reported outcome scores (PROs) and rates of achieving the minimal clinically important difference (MCID), the patient-acceptable symptomatic state (PASS), and the maximal outcome improvement (MOI) on adolescents following primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Second, to determine risk factors for revision surgery. METHODS: Prospectively collected data from two high-volume hip arthroscopy centers were retrospectively reviewed on adolescents (≤19 years old) who underwent primary hip arthroscopy between November 2008 and February 2019. Adolescents with a minimum 2-year follow-up for the modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), Hip Outcome Score-Sports Specific Subscale (HOS-SSS), International Hip Outcome Tool-12 (iHOT-12), and visual analog scale (VAS) for pain were included regardless of their growth plate status. Exclusion criteria were Tönnis grade >1, lateral center edge-angle <18°, and previous ipsilateral hip surgery or conditions. Preoperative and postoperative radiographic data, MCID, PASS, MOI, secondary surgeries, and complications were reported. A multivariable survival analysis for risk factors for secondary surgery was conducted. RESULTS: A total of 287 hips (249 patients) were included (74.9% females). The mean values for age, body mass index, and follow-up were 16.3 ± 1.3 years, 22.3 ± 3.5, and 26.6 ± 9.4 months, respectively. Further, 88.9% underwent labral repair, 81.5% femoroplasty, and 85.4% capsular closure. Improvement for all PROs was reported (P < .001) with high patient satisfaction (8.8 ± 1.5). Achievement for the MCID was 71.7%, 83.0%, 68.1%, and 79.5% for the mHHS, NAHS, HOS-SSS, and iHOT-12, respectively. Achievement for the PASS was 68.3% for the mHHS and 73.2% for the NAHS. The MOI for mHHS, NAHS, and VAS was 58.3%, 77.0%, and 59.6%, respectively. Rates of revision hip arthroscopy, cam recurrence, and heterotopic ossification were 5.8%, 1.7%, and 5.5%, respectively. Acetabular retroversion was found to be a risk factor for revision surgery (P = .03). CONCLUSION: The results of this multi-center study demonstrated that adolescents who underwent primary hip arthroscopy for FAIS reported significant improvement in all PROs, with satisfactory achievement rates for the MCID, PASS, MOI, and high patient satisfaction at a minimum 2-year follow-up. LEVEL OF EVIDENCE: IV, retrospective multicenter study.

Machine learning can accurately predict risk factors for all-cause reoperation after ACLR: creating a clinical tool to improve patient counseling and outcomes.

PURPOSE: Identifying predictive factors for all-cause reoperation after anterior cruciate ligament reconstruction could inform clinical decision making and improve risk mitigation. The primary purposes of this study are to (1) determine the incidence of all-cause reoperation after anterior cruciate ligament reconstruction, (2) identify predictors of reoperation after anterior cruciate ligament reconstruction using machine learning methodology, and (3) compare the predictive capacity of the machine learning methods to that of traditional logistic regression. METHODS: A longitudinal geographical database was utilized to identify patients with a diagnosis of new anterior cruciate ligament injury. Eight machine learning models were appraised on their ability to predict all-cause reoperation after anterior cruciate ligament reconstruction. Model performance was evaluated via area under the receiver operating characteristics curve. To explore modeling interpretability and radiomic feature influence on the predictions, we utilized a game-theory-based method through SHapley Additive exPlanations. RESULTS: A total of 1400 patients underwent anterior cruciate ligament reconstruction with a mean postoperative follow-up of 9 years. Two-hundred and eighteen (16%) patients experienced a reoperation after anterior cruciate ligament reconstruction, of which 6% of these were revision ACL reconstruction. SHapley Additive exPlanations plots identified the following risk factors as predictive for all-cause reoperation: diagnosis of systemic inflammatory disease, distal tear location, concomitant medial collateral ligament repair, higher visual analog scale pain score prior to surgery, hamstring autograft, tibial fixation via radial expansion device, younger age at initial injury, and concomitant meniscal repair. Pertinent negatives, when compared to previous studies, included sex and timing of surgery. XGBoost was the best-performing model (area under the receiver operating characteristics curve of 0.77) and outperformed logistic regression in this regard. CONCLUSIONS: All-cause reoperation after anterior cruciate ligament reconstruction occurred at a rate of 16%. Machine learning models outperformed traditional statistics and identified diagnosis of systemic inflammatory disease, distal tear location, concomitant medial collateral ligament repair, higher visual analog scale pain score prior to surgery, hamstring autograft, tibial fixation via radial expansion device, younger age at initial injury, and concomitant meniscal repair as predictive risk factors for reoperation. Pertinent negatives, when compared to previous studies, included sex and timing of surgery. These models will allow surgeons to tabulate individualized risk for future reoperation for patients undergoing anterior cruciate ligament reconstruction. LEVEL OF EVIDENCE: III.

Duration of Care and Operative Time Are the Primary Drivers of Total Charges After Ambulatory Hip Arthroscopy: A Machine Learning Analysis.

PURPOSE: To develop a machine learning algorithm to predict total charges after ambulatory hip arthroscopy and create a risk-adjusted payment model based on patient comorbidities. METHODS: A retrospective review of the New York State Ambulatory Surgery and Services database was performed to identify patients who underwent elective hip arthroscopy between 2015 and 2016. Features included in initial models consisted of patient characteristics, medical comorbidities, and procedure-specific variables. Models were generated to predict total charges using 5 algorithms. Model performance was assessed by the root-mean-square error, root-mean-square logarithmic error, and coefficient of determination. Global variable importance and partial dependence curves were constructed to show the impact of each input feature on total charges. For performance benchmarking, the best candidate model was compared with a multivariate linear regression using the same input features. RESULTS: A total of 5,121 patients were included. The median cost after hip arthroscopy was $19,720 (interquartile range, $12,399-$26,439). The gradient-boosted ensemble model showed the best performance (root-mean-square error, $3,800 [95% confidence interval, $3,700-$3,900]; logarithmic root-mean-square error, 0.249 [95% confidence interval, 0.24-0.26]; R2 = 0.73). Major cost drivers included total hours in facility less than 12 or more than 15, longer procedure time, performance of a labral repair, age younger than 30 years, Elixhauser Comorbidity Index (ECI) of 1 or greater, African American race, residence in extreme urban and rural areas, and higher household and neighborhood income. CONCLUSIONS: The gradient-boosted ensemble model effectively predicted total charges after hip arthroscopy. Few modifiable variables were identified other than anesthesia type; nonmodifiable drivers of total charges included duration of care less than 12 hours or more than 15 hours, operating room time more than 100 minutes, age younger than 30 years, performance of a labral repair, and ECI greater than 0. Stratification of patients based on the ECI highlighted the increased financial risk borne by physicians via flat reimbursement schedules given variable degrees of comorbidities. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Editorial Commentary: Autograft Beats Allograft for Most Knee Ligament Surgery.

Knee ligament reconstruction can be performed with autograft or allograft. The use of an autograft has been shown to improve outcomes in primary anterior cruciate ligament reconstruction for young, active patients, and also in revision anterior cruciate ligament reconstruction surgery. A systematic review of posterior cruciate ligament reconstruction showed no difference in outcomes between autograft and allograft tissue. There is a paucity of data comparing autograft versus allograft for fibular collateral ligament and posterolateral corner reconstructions, alone or combined with other ligament surgery. Allograft advantages include no donor site morbidity and reduced operative time. Disadvantages include increased cost and higher failure rates in younger patients. Autograft tissue should be considered in younger, active patients whenever possible.

Hamstring Autograft Anterior Cruciate Ligament Reconstruction Using an All-Inside Technique With and Without Independent Suture Tape Reinforcement.

PURPOSE: To compare the (1) rates of complications and reoperations, (2) rate of anterior cruciate ligament (ACL) graft failure, and (3) patient-reported outcomes (PROs) among patients after hamstring autograft ACL reconstruction (ACLR) with and without independent suture tape reinforcement at a minimum 2-year clinical follow-up. METHODS: We performed a 1:2 matched-cohort comparison of patients who underwent hamstring autograft ACLR with and without independent suture tape reinforcement between July 2011 and July 2017. Patients were matched according to age, sex, body mass index, preinjury Tegner activity score, and concomitant meniscal injury. Medical records were reviewed for demographic characteristics, additional injuries, and concomitant procedures. PRO scores (including Tegner activity, Lysholm, and International Knee Documentation Committee scores) and physical examination findings were collected both preoperatively and at a minimum of 2 years postoperatively. RESULTS: Overall, 108 patients who underwent ACLR were included: 36 patients (mean age, 25.3 years; range, 13-44 years) with independent suture tape reinforcement and 72 patients (mean age, 24.9 years; range, 13-54 years) without suture tape reinforcement. Overall, 5 of 36 suture tape patients (14%) and 10 of 72 control patients (14%) underwent reoperations. At an average follow-up of 26.1 months in the suture tape cohort and 31.3 months in the control cohort, 1 patient in the suture tape cohort and 4 patients in the control cohort experienced graft failure. There were no statistically significant differences between the suture tape and control groups regarding return-to-sport rate (89% and 88%, respectively), postoperative International Knee Documentation Committee score (94.4 and 93.8, respectively), and postoperative Lysholm score (95.6 and 94, respectively). There was a statistically significant difference between the suture tape and control groups in postoperative Tegner activity score, at 7.1 (95% confidence interval, 6.5-7.6) and 6.4 (95% confidence interval, 6.2-6.6), respectively (P = .026). CONCLUSIONS: ACLR with hamstring autograft and independent suture tape reinforcement was performed safely with low rates of complications, graft failure, and reoperations with similar PROs, function, and return-to-sport rates when compared with hamstring autograft ACLR without suture tape reinforcement at a minimum 2-year follow-up. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Is Labral Size Predictive of Failure With Repair in Hip Arthroscopy?

PURPOSE: To assess whether labral size is predictive of labral repair failure or shows an association with patient outcomes after hip arthroscopy. METHODS: We performed a retrospective chart review of patients who underwent arthroscopic hip labral repair. Labral size was measured in 4 quadrants with an arthroscopic probe. The average size across torn labral segments was assessed for failure as determined by the change in patient-reported outcomes, the rate at which subjects achieved the minimal clinically important difference and patient acceptable symptomatic state, and the need for additional surgery. Outcomes were evaluated for any continuous correlation as well as significant differences between the middle 50% of labral sizes and classes of labral sizes derived from upper and lower quartile and decile ranges. Included hips were those from patients aged between 18 and 55 years with 2-year postoperative follow-up and lateral center-edge angles between 25° and 40°. RESULTS: The study included 571 hips. Labral width did not show a significant difference between hips requiring revision and those not requiring revision (P = .4054). No significant correlation was found between labral width and the change in the International Hip Outcome Tool 12 score (R2 = 0.05780), modified Harris Hip Score (R2 = 0.19826), or Nonarthritic Hip Score (R2 = 0.23543) from preoperatively to 2 years postoperatively. Hips with labral sizes in the upper decile of our cohort showed significantly decreased improvement in the International Hip Outcome Tool 12 score (P = .0287) and Nonarthritic Hip Score (P = .0490) compared with the middle 50% of labral sizes. No statistically significant difference was found in the rate at which the groups achieved the minimal clinically important difference or patient acceptable symptomatic state. CONCLUSIONS: Hypertrophic labra in the largest 10th percentile showed lower postoperative outcome scores. However, no detectable clinical benefit was found in terms of patient-perceived clinical difference or acceptable symptomatic state. For most patients, labral size does not appear to significantly alter patient outcomes or the need for arthroplasty. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Medial Versus Lateral Meniscus Root Tears: Is There a Difference in Injury Presentation, Treatment Decisions, and Surgical Repair Outcomes?

PURPOSE: To determine (1) the demographic characteristics as well as radiographic findings of medial versus lateral meniscal root tears at time of presentation, (2) treatment decisions and clinical outcomes of patients undergoing medial versus lateral root repair, and (3) risk factors for worse clinical and radiographic outcomes. METHODS: A retrospective review was performed to identify patients with symptomatic, medial, or lateral meniscus posterior root tears with a minimum 2-year follow-up. Radiographs were graded using Kellgren-Lawrence scores. Subanalysis was performed on 62 patients who underwent root repair. Tegner, Lysholm, International Knee Documentation Committee scores, and progression to arthroplasty were analyzed in the repair groups. Patient demographics, radiographic findings, and clinical outcomes were compared between medial meniscus posterior horn root tear (MMRT) and lateral meniscus root repair (LMRT). RESULTS: Of the 141 root tears, 109 were MMRTs, 30 were LMRTs, and 2 patients had both. At the time of injury, patients with MMRTs had a significantly higher age (MMRT = 51.4 vs LMRT=24.6, P < .0001), body mass index (MMRT = 32.1 vs LMRT 25.8, P < .0001), Kellgren-Lawrence score (MMRT = 1.3 vs LMRT=0.6, P < .0001), and higher rate of major meniscal extrusion (MMRT = 72% vs LMRT = 20%, P < .0001). Of the 30 LMRT, 30/30 (100.0%) were treated with meniscal repair. With MMRT, 52/109 (48%) were treated nonoperatively, 27/109 (25%) with partial meniscectomy, and 30/109 (27%) with meniscal repair. Sixty-two patients underwent meniscus root repair with an average 41-month follow-up. LMRT had significantly increased International Knee Documentation Committee (LMRT = 89.5, MMRT = 80.4, P = .02) and Tegner scores (LMRT = 6.5, MMRT = 5.1, P < .05) compared with MMRT. CONCLUSIONS: Compared with MMRTs, LMRTs occur in younger male patients with lower body mass index, less cartilage degeneration, less extrusion on magnetic resonance imaging, and more commonly with a ligament injury. Although good to excellent clinical outcomes were attained in select patients for both medial and lateral meniscus root repair, LMRTs may have better results after repair, suggesting that differences in injury and patient characteristics may contribute to differences in these outcomes. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

No difference between single and staged posterolateral corner surgical procedures in the multiligament injured/dislocated knee.

PURPOSE: Posterolateral corner (PLC) injuries commonly occur in the setting of a dislocated knee and often require multiple procedures due to concomitant vascular, nerve, and soft tissue involvement. Debate persists regarding single vs staged surgery. The purpose of this study was to compare knee function after single and staged surgery for PLC injury. METHODS: Patients who underwent surgery for a PLC injury (KD I, IIIL, IV) with minimum follow-up of 2 years were included. Patients treated with staged and single surgery were matched according to age, sex, and KD grade. Lysholm and International Knee Documentation Committee (IKDC) subjective scores were obtained. Risk factors for poor knee function were assessed, including age, nerve, vascular, meniscal and articular cartilage injuries. RESULTS: Twenty single-surgery patients with a median age of 24 years (median follow-up 5.3 years, range 2-18.3) and 20 staged surgery patients with a median age of 26 years (median follow-up 4.3 years, range 2-19.8) were studied. The mean Lysholm score was 78.7 (± 20.3) in the single surgery and 84.2 (± 17.8) in the staged surgery cohort (n.s.). The mean IKDC score was 80.8 (± 21.1) in the single and 74.9 (± 18.9) in the staged surgery cohort (n.s.). Age at injury, peroneal, vascular, meniscal or cartilage injury were not associated with poor knee outcome. CONCLUSION: This study demonstrates similar knee function among patients with PLC injuries treated with single or staged surgical procedures. The need for staged surgery for the dislocated knee with PLC involvement should be individualized based on specific knee and patient-related factors. LEVEL OF EVIDENCE: III.

Editorial Commentary: What Is the Best Graft Source for Posterior Cruciate Ligament Reconstruction?

In 2018, the best available evidence has failed to show any significant clinical or functional difference between autograft and allograft for posterior cruciate ligament reconstruction. Autograft patients may have higher complication rates. Both groups show good functional outcome after reconstruction.

Editorial Commentary: Anatomic Posterolateral Corner Reconstruction: All-Autograft Technique.

Several techniques for posterolateral corner reconstruction have been described in the literature, typically using allogeneic tissue. Autograft reconstruction has potential value because of decreased cost and limited allograft supply in some locations. Initial results of this hamstring autograft tendon technique are promising, but further research is needed to directly compare reconstruction graft sources.

Bilateral Hip Arthroscopy: Can Results From Initial Arthroscopy for Femoroacetabular Impingement Predict Future Contralateral Results?

PURPOSE: To determine the degree of correlation of radiographic measurements, degree of correlation of intraoperative pathology, and difference in outcomes between sides of patients requiring staged bilateral hip arthroscopy. METHODS: Two high-volume hip preservation centers retrospectively reviewed hip preservation databases for staged bilateral hip arthroscopies conducted between 2008 and 2015. Patients were separated into those who presented with bilateral hip pain and those that presented with unilateral pain and developed contralateral pain >2 years later. Patients were analyzed for radiographic correlation (alpha angle, lateral center edge angle, anterior center edge angle, magnetic resonance imaging alpha angle, Tönnis grade) and correlation of intraoperative pathology (acetabular labrum articular disruption grade, Outerbridge grade/location, Villar class ligamentum teres tears, labral tear location, symmetry of Seldes tear types, and the differences between operative procedures). Patient-reported outcomes were analyzed (modified Harris Hip Score, Non-Arthritic Hip Score, International Hip Outcome Tool-12, hip outcome score-sport specific subscale, visual analog scale, patient satisfaction). Correlative tests included Pearson and Spearman; univariate and multivariate analysis for differences included χ-square test and Student t tests for ordinal and continuous variables respectively. RESULTS: A total of 133 of 2,705 patients (4.6%) underwent bilateral hip arthroscopy. Radiographic alpha angle, magnetic resonance imaging alpha angle, lateral center edge angle, and anterior center edge angle demonstrated strong correlation (Pearson's coefficients 0.651, 0.648, 0.644, 0.667, respectively, P < .0001). Tönnis grade was weakly correlated (Pearson's coefficient 0.286, P = .001). Intraoperative pathology was moderately correlated (Pearson's coefficients for acetabular Outerbridge location, 0.300, P = .0170; acetabular labrum articular disruption, 0.490, P < .0001; acetabular Outerbridge; 0.530; P < .0001; femoral head Outerbridge, 0.459, P < .0001; Villar class, 0.393, P < .0001; and labral tear location, 0.468, P < .0001). Labral tear Seldes type was compared with Bowker's symmetry test and there was no significant difference between sides. There were no significant differences in surgical interventions performed between sides. Patients with bilateral hip arthroscopies significantly improved in all measured patient-reported outcomes and had a high patient satisfaction after both procedures. Final patient-reported outcomes and change in patient-reported outcomes were not different between procedures; follow up ranged from 3 months to 8 years. CONCLUSIONS: This study demonstrated an incidence of 4.6% of patients who require bilateral hip arthroscopy. These patients can expect significant improvement after surgical intervention. Patients that had 1 side done gained similar improvement when the contralateral side was performed. Preoperative radiographic, intraoperative pathology, and procedures performed were similar between hips. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Comprehensive Case-Based Review of Knee Ligament Injuries.

The management of knee ligament injuries continues to evolve, and much debate persists over the timing of surgery, repair versus reconstruction, surgical technique, postoperative rehabilitation, graft selection, and fixation. Surgeons should be aware of updates on the best management strategies of knee ligament injuries in 2018 and understand the important history and physical examination findings of the knee with ligamentous injury; the anterior cruciate ligament; the role of the anterolateral ligament and lateral extra-articular tenodesis; combined anterior cruciate ligament and medial collateral ligament injuries; the posterior cruciate ligament; medial collateral ligament repair versus reconstruction; posterolateral corner repair versus reconstruction; the role of coronal plane osteotomies, including high tibial osteotomy and distal femoral osteotomy; the role of sagittal plane osteotomies, including anterior closing wedge osteotomy and anterior opening wedge osteotomy; the initial management of the multiligament-injured knee; and five keys to avoiding complications in the multiligament-injured knee. The best available evidence and sample case presentations help guide surgical decision making and improve patient outcomes.

High tibial osteotomy with modern PEEK implants is safe and leads to lower hardware removal rates when compared to conventional metal fixation: a multi-center comparison study.

PURPOSE: Various implant materials have been used in medial, opening-wedge high tibial osteotomy (HTO) including traditional metal and modern polyetheretherketone (PEEK) implants. The purpose of this study was to compare metal and PEEK implants and determine safety, varus deformity correction, as well as short- to mid-term hardware removal and arthroplasty rates. METHODS: HTO performed with metal and PEEK implants were reviewed between 2000 and 2015 at two institutions with a minimum of 2 years follow-up. Postoperative complications, radiographic measures, and osteotomy union were compared between groups using Kruskal-Wallis and Fisher's exact testing. Survival free of hardware removal and arthroplasty was compared between groups using Kaplan-Meier testing. Risk factors for HTO conversion to arthroplasty were examined using Cox proportional hazards regression. RESULTS: Ninety-five HTOs were performed in 90 patients (59 M, 31 F) using 50 metal and 45 PEEK implants. Mean follow-up was 4.2 years (range 2.0-16.5). Two metal and two PEEK HTO patients experienced nonunions, resulting in revision HTO at a mean of 1.0 years postoperatively (range 0.4-1.4 years). Both implant groups demonstrated similar, significant improvements in coronal deformity, with mean angulation improving from 6.0° and 5.4° varus preoperatively to 1.1° and 1.0° valgus postoperatively for the metal (p < 0.01) and PEEK groups (p < 0.01), respectively. 2- and 5-year hardware removal-free survival was 94% and 94% for PEEK, which was significantly superior to 80% and 73% observed for metal (p = 0.02). 2- and 5-year arthroplasty-free survival was similar for the metal (98% and 94%) and PEEK groups (100% and 78%) (n.s.). HTO performed for focal cartilage defects was observed to demonstrate decreased arthroplasty risk (HR 0.36, p = 0.03) when compared to HTO performed for osteoarthritis. CONCLUSIONS: Both metal and PEEK implants were found to be effective in obtaining and maintaining coronal varus deformity correction, with 88% overall arthroplasty-free survival at 5 years. Metal fixation demonstrated a higher rate of hardware removal while HTO performed for medial compartment osteoarthritis predicted conversation to arthroplasty. LEVEL OF EVIDENCE: III.

Posterolateral corner of the knee: an expert consensus statement on diagnosis, classification, treatment, and rehabilitation.

PURPOSE: To develop a statement on the diagnosis, classification, treatment, and rehabilitation concepts of posterolateral corner (PLC) injuries of the knee using a modified Delphi technique. METHODS: A working group of three individuals generated a list of statements relating to the diagnosis, classification, treatment, and rehabilitation of PLC injuries to form the basis of an initial survey for rating by an international group of experts. The PLC expert group (composed of 27 experts throughout the world) was surveyed on three occasions to establish consensus on the inclusion/exclusion of each item. In addition to rating agreement, experts were invited to propose further items for inclusion or to suggest modifications of existing items at each round. Pre-defined criteria were used to refine item lists after each survey. Statements reaching consensus in round three were included within the final consensus document. RESULTS: Twenty-seven experts (100% response rate) completed three rounds of surveys. After three rounds, 29 items achieved consensus with over 75% agreement and less than 5% disagreement. Consensus was reached in 92% of the statements relating to diagnosis of PLC injuries, 100% relating to classification, 70% relating to treatment and in 88% of items relating to rehabilitation statements, with an overall consensus of 81%. CONCLUSIONS: This study has established a consensus statement relating to the diagnosis, classification, treatment, and rehabilitation of PLC injuries. Further research is needed to develop updated classification systems, and better understand the role of non-invasive and minimally invasive approaches along with standardized rehabilitation protocols. LEVEL OF EVIDENCE: Consensus of expert opinion, Level V.