Risk of Arthroplasty in Patients with Subchondral Insufficiency Fractures of the Knee: A Matched Study of the Implantable Shock Absorber using a Validated Predictive Model.

Subchondral insufficiency fractures of the knee (SIFK) can result in high rates of osteoarthritis and arthroplasty. The implantable shock absorber (ISA) implant is a titanium and polycarbonate urethane device which reduces the load on the medial compartment of the knee by acting as an extra-articular load absorber while preserving the joint itself. The purpose of this study was to evaluate whether partially unloading the knee with the ISA altered the likelihood of progression to arthroplasty utilizing a validated predictive risk model (SIFK score). A retrospective case-control (2:1) study was performed on patients with SIFK without any previous surgery and on those implanted with the ISA with the primary outcome being progression to arthroplasty compared with nonoperative treatment at 2 years. Baseline and final radiographs, as well as magnetic resonance imagings, were reviewed for the evaluation of meniscus or ligament injuries, insufficiency fractures, and subchondral edema. Patients from a prospective study were matched using the exact SIFK Score, a validated predictive score for progression to arthroplasty in patients with SIFK, to those who received the ISA implant. Kaplan-Meier analysis was conducted to assess survival. A total of 57 patients (38 controls:19 ISA) with a mean age of 60.6 years and 54% female were included. The SIFK score was matched exactly between cases and controls for all patients. The 2-year survival rate of 100% for the ISA group was significantly higher than the corresponding rate of 61% for the control group (p < 0.01). In ISA, 0% of the patients converted to arthroplasty at 2 years, and 5% (one patient) had hardware removal at 1 year. When stratified by risk, the ISA group did not have a significantly higher survival compared with low-risk (p = 0.3) or medium-risk (p = 0.2) controls, though it had a significantly higher survival for high-risk groups at 2 years (100 vs. 15%, p < 0.01). SIFK of the medial knee can lead to significant functional limitation and high rates of conversion to arthroplasty. Implants such as the ISA have the potential to alter the progression to arthroplasty in these patients, especially those at high risk.

Association of Postless Distraction in Hip Arthroscopy With Decreased Postoperative Groin Numbness.

BACKGROUND: Patients undergoing hip arthroscopy performed with perineal post distraction may experience postoperative nerve and soft tissue complications related to the perineal post. PURPOSE: To compare rates of postoperative numbness in patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS) with postless distraction and perineal post distraction methods. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective review of prospectively collected data was performed on patients who underwent hip arthroscopy for FAIS, with postless distraction and perineal post distraction methods. Medical records were reviewed for patient characteristics, radiographic data, and operative data. Traction force data were collected on all patients prospectively using a previously validated method. Data on postoperative numbness (presence/absence and regionality) were collected prospectively at routine postoperative follow-ups (6-week and 3-month postoperative clinic visits). RESULTS: Overall, 195 patients were included, with 94 patients (mean age, 30.4 years) in the postless distraction cohort and 101 patients (mean age, 31.9 years) in the post distraction cohort. The overall numbness rates were 29 of 94 (30.9%) in the postless distraction group and 45 of 101 (44.6%) in the post distraction group (P = .068). Rates of postoperative groin numbness were 1 of 94 (1.1%) in the postless distraction group and 19 of 101 (18.8%) in the post distraction group (P < .001). Multivariate analysis for postoperative groin numbness demonstrated post distraction (odds ratio [OR], 16.5; P = .022) and traction time (OR, 1.7; P = .020) to be statistically significant variables. In subgroup analysis of the post distraction group, traction time (P = .015), but not holding (P = .508) or maximum traction force (P = .665), reached statistical significance in patients who developed postoperative groin numbness. CONCLUSION: Postless distraction hip arthroscopy demonstrated a statistically significantly lower rate of groin numbness rates in comparison with a traditional perineal post distraction method. In the post distraction group, traction time was significantly higher in patients who developed postoperative groin numbness than in those who did not.

Acetabular Labral Reconstruction: Review of Techniques and Outcomes.

PURPOSE OF REVIEW: To analyze advances in labral reconstruction, and to discuss the literature relating to efficacy, outcomes, and technical considerations of labral reconstruction. RECENT FINDINGS: The available evidence suggests that labral reconstruction is a safe and effective procedure that can improve pain and function in patients with severe and/or complex labral tears. The superiority of labral reconstruction over labral repair is uncertain, and it remains unclear what graft type and technique should be used in labral reconstructions. Labral reconstruction assists in restoring the function of the labrum of the hip. It consistently restores stability of the hip joint and demonstrates good clinical outcomes at follow-up. The optimal graft type, technique, and extent are still debated, and more research is needed. Ultimately, despite this uncertainty, labral reconstruction is proving to be a valuable tool for hip preservation specialists.

Improved 2-Year Freedom from Arthroplasty in Patients with High-Risk SIFK Scores and Medial Knee Osteoarthritis Treated with an Implantable Shock Absorber versus Non-Operative Care.

OBJECTIVE: Subchondral insufficiency fracture of the knee (SIFK) is associated with high rates of osteoarthritis (OA) and arthroplasty. The implantable shock absorber (ISA) is an extra-capsular implant that unloads the medial knee compartment. This study compared the 2-year freedom from arthroplasty rates in subjects with medial knee OA and SIFK when treated with an ISA versus a matched cohort of patients treated non-surgically. DESIGN: This retrospective case-control study compared 2-year conversion rates to arthroplasty in SIFK score-, age-, and body mass index (BMI)-matched control subjects without prior surgical history with ISA-implanted subjects from an ongoing prospective study. Baseline and final radiographs, and MRIs were reviewed for evaluation of meniscus or ligament injuries, insufficiency fractures, and subchondral edema. Kaplan-Meier analysis assessed survival. RESULTS: Forty-two patients (21 Control: 21 ISA), mean age = 52.3 ± 8.7 years, BMI = 29.5 ± 3.9 kg/m2, 40% female were evaluated. Both ISA and Control arms had the same numbers of low (n = 4), medium (n = 11), and high-risk (n = 6) SIFK scores. One- and 2-year freedom-from-arthroplasty rates were both 100% for ISA subjects, and 76% and 55%, respectively, for Controls (P = 0.001 for cross-group comparison). Control knees with low, medium, and high-risk SIFK scores had respective 1- and 2-year survival rates of 100% and 100%, 90% and 68% (P = 0.07 vs. ISA), and 33% and 0% (P = 0.002 vs. ISA). CONCLUSIONS: ISA intervention was strongly associated with avoidance of arthroplasty at a minimum 2 years, especially in patients with high-risk SIFK scores. SIFK severity scoring predicted relative risk of conversion to arthroplasty through at least 2 years in non-surgically treated subjects.

Impact of tumour stage on the surgical outcomes of scapular chondrosarcoma.

PURPOSE: Chondrosarcomas are common primary bone tumours in adults, often affecting the flat bones. Oncologic outcomes are often tied to tumour grade; however, grade is only a factor in the aggressiveness of a tumor. Extracompartmental extension, or tumor stage, has been found to be predictive of a poor outcome in other flat bone chondrosarcomas; however, this relationship has not been identified in the scapula. The purpose of the current study was to analyze the impact of tumour stage on the outcome of patients with scapular chondrosarcoma. METHODS: Thirty-nine patients (26 males:13 females) with a mean age of 46 ± 17 undergoing surgical resection of a scapular chondrosarcomas were reviewed. Most patients had grade 1 (n = 24) tumors, with 26 (67%) having extracompartmental extension. The mean follow-up was eight years. RESULTS: The ten year disease-specific survival was 77%. High-grade tumours (HR 18.15, p < 0.01) were associated with death due to disease. The ten year local recurrence- and metastatic-free survival were 77% and 74%. Positive surgical margins (HR 8.85, p < 0.01) were associated with local recurrence, and local recurrence was associated with metastatic disease (HR3.37, p = 0.04). All disease recurrences and death due to disease occurred in patients with extracompartmental extension (p < 0.05). CONCLUSION: Extracompartmental extension was associated with a worse oncologic outcome in patients with scapular chondrosarcomas. Positive margins were associated with local recurrence, which was associated with metastatic disease; wide local excision with negative margins should be a goal for all patients, regardless of tumour grade.

Are Baseball Statistics an Appropriate Tool for Assessing Return to Play in Injured Pitchers? Analysis of Statistical Variability in Healthy Players.

BACKGROUND: Basic pitcher statistics have been used to assess performance in pitchers after injury or surgery without being validated. Even among healthy pitchers, the normal variability of these parameters has not yet been established. PURPOSE: To determine (1) the normal variability of basic and advanced pitcher statistics in healthy professional baseball pitchers and (2) the minimum pitches needed to predict these parameters. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Publicly available data from the MLB Statcast and PITCHf/x databases were used to analyze MLB pitchers during the 2015 and 2016 seasons who recorded a minimum of 100 innings without injury. Basic and advanced baseball pitcher statistics were analyzed. The variability of each parameter was assessed by computing the coefficient of variation (CV) between individual pitchers and across all pitchers. A CV <10 was indicative of a relatively constant parameter, and parameters with a CV >10 were generally considered inconsistent and unreliable. The minimum number of pitches needed to be followed for each variable was also analyzed. RESULTS: A total of 118 pitchers, 55 baseball-specific statistical metrics (38 basic and 17 advanced), and 7.5 million pitches were included and analyzed. Of the 38 basic pitcher statistics, only fastball velocity demonstrated a CV <10 (CV = 1.5), while 6 of 17 (35%) advanced metrics demonstrated acceptable consistency (CV <10). Release position from plate and velocity from the plate were the 2 most consistent advanced parameters. When separated by pitch type, these 2 parameters were the most constant (lowest CV) across every pitch type. CONCLUSION: We recommend against utilizing nonvalidated statistical measures to assess performance after injury, as they demonstrated unacceptably high variability even among healthy, noninjured professional baseball pitchers. It is our hope that this study will serve as the foundation for the identification and implementation of validated pitcher-dependent statistical measures that can be used to assess return-to-play performance after injury in the future.

Post-arthroscopic Subchondral Insufficiency Fractures of the Knee Yield High Rate of Conversion to Arthroplasty.

PURPOSE: To evaluate both the potential causes and resultant outcomes in patients in whom subchondral insufficiency fracture of the knee (SIFK) develops after arthroscopy. METHODS: We performed a retrospective review of all patients with a magnetic resonance imaging diagnosis of SIFK after arthroscopic meniscectomy and chondroplasty over a 12-year period. RESULTS: A total of 28 patients were included, with a mean age of 61 years and mean follow-up period of 5.7 years. SIFK showed a predilection for the medial compartment (n = 25, 89%), specifically the medial femoral condyle (n = 21, 75%). In 7 patients (25%), SIFK developed in both the femoral condyle and tibial plateau in the ipsilateral compartment. Fifteen patients (54%) went on to conversion to arthroplasty at a mean of 0.72 years. The rate of survival free of conversion to arthroplasty was 57%, 45%, and 40% at 1 year, 2 years, and 5 years, respectively. Furthermore, 63% of patients with a meniscal tear and SIFK in the same compartment went on to arthroplasty (P = .04). There was an increased risk of conversion to arthroplasty if SIFK was present in both the femur and tibia in the same compartment (P = .04). A higher Kellgren-Lawrence grade at the time of the SIFK diagnosis increased the likelihood of eventual arthroplasty (P = .03). The presence of SIFK in both the femur and tibia in the ipsilateral compartment, an increased Kellgren-Lawrence grade, and a meniscal tear or prior meniscectomy in the same compartment as SIFK were associated with an increased risk of eventual arthroplasty. CONCLUSIONS: Post-arthroscopic SIFK most commonly occurs in the medial compartment, particularly in patients who underwent a prior meniscectomy. The presence of meniscal root and radial tears in these patients is notable (75%). Ultimately, there is a high rate of progression of arthrosis (33%) and eventual conversion to arthroplasty. LEVEL OF EVIDENCE: Level IV, case series.

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.

Pre-operative patella alta does not affect midterm clinical outcomes and survivorship of patellofemoral arthroplasty.

PURPOSE: The purpose of this study was to evaluate the effect of preoperative patella alta on clinical outcomes, survivorship, and complication and reoperation rates on patellofemoral arthroplasty (PFA). METHODS: All patients who underwent PFA for isolated patellofemoral arthritis by a single surgeon at our institution were identified. Preoperative radiographs were measured by two independent observers for patellar height using the Caton Deschamps (CD), Insall-Salvati (IS), and Blackburne-Peele (BP) methods. Patients were classified as either "patella alta" or "non-patella alta" for all three measurement methods. Clinical scores including KSS Pain, KSS Function, and Tegner Activity Scores were collected pre- and post-operatively. Failure was defined as conversion to total knee arthroplasty (TKA). Clinical outcomes and survivorship were compared between patients with "patella alta" and "non-patella alta" height measurements. RESULTS: There were 119 patients with 153 knees (86% female) included in the study with a mean age of 55.8 years. Outcome scores improved from pre-operative to post-operative for both patella alta and non-patella alta patients for Tegner, KSS pain and KSS function scores. The mean change in Tegner scores for patella alta and non-patella alta patients were not significantly different for CD (p = 0.24), IS (p = 0.25) or BP measurements (p = 0.39). The mean change in KSS pain scores between groups were not significantly different for CD (p = 0.33) or IS measurements (p = 0.22), but was improved more significantly in patella alta patients vs non-patella alta patients (21.2 and 14.4; p = 0.02) for BP measurement. The mean change in KSS function scores between groups was not significantly different for CD (p = 0.61) IS (p = 0.90) or BP measurements (p = 0.79). The overall survivorship from conversion to total knee arthroplasty (TKA) was 94.1% at a mean follow-up time of 5.0 (SD 2.6) years. There were no significant differences in survivorship from TKA between patella alta and non-patella alta groups (CD: p = 0.72, IS: p = 0.63, BP: p = 0.66). CONCLUSIONS: This study suggests that there are no significant differences in clinical outcome scores or survivorship from TKA between patella alta and non-patella alta patients who underwent onlay design PFA. Both patella alta and non-patella alta patients demonstrated excellent improvement in outcome scores from pre-operative to post-operative. LEVEL OF EVIDENCE: IV.

Significant Changes in the Diagnosis, Injury Severity and Treatment for Anterior Shoulder Instability Over Time in a U.S. Population.

PURPOSE: To report the annual incidence of anterior shoulder instability (ASI) diagnosis, injury severity, and surgical stabilization in a U.S. population. METHODS: An established U.S. geographic database was used to identify patients < 40 years old with diagnoses of ASI from 1994-2016. Medical records were reviewed to obtain patient demographics, histories, imaging results, and surgical details. Age- and sex-specific incidence rates were calculated and adjusted to the 2010 U.S. population. Poisson regression was performed to examine trends by timeline, sex and age. RESULTS: The study population consisted of 652 patients with ASI and a mean age of 21.5 years (range, 3.6-39.5). Comparing 2015-2016 to 1994-1999, we found an increase in the number of dislocations (from 1.0-1.9; P = 0.016) and total instability events (from 2.3-3.4; P = 0.041) per patient prior to presentation to a physician. There was a trend in increased diagnosis of bony Bankart and/or Hill-Sachs on MRI over time, with these lesions documented in 96% of patients undergoing MRI in 2015-2018 compared to 52.9% in 1994-1999 (P < .001). The use of arthroscopic procedures increased and peaked in 2005-2009 (90% of surgical cases performed). The proportion of open Latarjet procedures increased from 2010-2014 (14%) and 2015-2018 (31%). CONCLUSIONS: The age- and sex- adjusted incidence of ASI diagnosis in a U.S. population from 1994-2016 is comparable to that demonstrated in Canadian and European populations. This study demonstrates an increasing number of instability events prior to surgical evaluation, which may correlate with patients' more commonly presenting with bone loss and requiring more aggressive surgical treatment or that ASI is being more frequently cared for and documented by present-day orthopedic surgeons. LEVEL OF EVIDENCE: Level III, cross-sectional study.

Spontaneous Osteonecrosis/Subchondral Insufficiency Fractures of the Knee: High Rates of Conversion to Surgical Treatment and Arthroplasty.

BACKGROUND: Spontaneous osteonecrosis of the knee has recently been termed subchondral insufficiency fracture of the knee (SIFK) to appropriately recognize the etiology of mechanical overloading of the subchondral bone. The purpose of this study was to assess clinical outcomes of SIFK based on progression to surgical treatment and arthroplasty, and to evaluate the risk factors that increase the progression to arthroplasty. METHODS: A retrospective review was performed on patients with a diagnosis of SIFK, as confirmed with use of magnetic resonance images (MRIs). Baseline and final radiographs were reviewed. Baseline MRIs were also reviewed for injury characteristics. Failure was defined as progression to surgical treatment or conversion to arthroplasty. RESULTS: Two hundred twenty-three patients (71% female) with a mean age of 65.1 years were included. SIFK affected 154 femora (69%) and 123 tibiae (55%), with medial compartment involvement in 198 knees (89%); 74% of medial menisci had root or radial tears, with a mean extrusion of 3.6 mm. Varus malalignment was identified in 54 (69%) of 78 knees. Seventy-six (34%) of all patients progressed to surgical intervention at 2.7 years, and 66 (30%) underwent arthroplasty at 3.0 years. The rates of conversion to surgical intervention and arthroplasty increased to 47% (37 of 79; p = 0.04) and 37% (29 of 79; p = 0.09), respectively, in patients with >5 years of follow-up. The 10-year survival rate free of arthroplasty for patients with SIFK on the medial femoral condyle (p < 0.01), SIFK on the medial tibial plateau (p < 0.01), medial meniscal extrusion (p = 0.01), varus alignment (p = 0.02), and older age (per year older; p = 0.003) was significantly higher than the survival rates of those without each respective condition. CONCLUSIONS: Subchondral insufficiency fractures predominantly involve the medial compartment of the knee and commonly present with medial meniscal root and radial tears. Approximately one-third of patients progressed to total knee arthroplasty. Baseline arthritis, older age, location of the insufficiency fracture on both the medial femoral condyle and medial tibial plateau, meniscal extrusion, and varus malalignment were all associated with progression to arthroplasty. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The SIFK score: a validated predictive model for arthroplasty progression after subchondral insufficiency fractures of the knee.

PURPOSE: The purpose of this study was to create a predictive model utilizing baseline demographic and radiographic characteristics for the likelihood that a patient with subchondral insufficiency fracture of the knee will progress to knee arthroplasty with emphasis on clinical interpretability and usability. METHODS: A retrospective review of baseline and final radiographs in addition to MRIs were reviewed for evaluation of insufficiency fractures and associated injuries. Patient and radiographic factors were used in building predictive models for progression to arthroplasty with Train: Validation: Test subsets. Multiple models were compared with emphasis on clinical utility. RESULTS: Total of 249 patients with a mean age of 64.6 (SD 10.5) years were included. Knee arthroplasty rate was 27% at mean of 4 years of follow-up. Lasso Regression was non-inferior to other models and was chosen for ease of interpretability. In order of importance, predictors for progression to arthroplasty included lateral meniscus extrusion, Kellgren-Lawrence Grade 4, SIFK on MFC, lateral meniscus root tear, and medial meniscus extrusion. The final SIFK Score stratified patients into low-, medium-, and high-risk categories with arthroplasty rates of 8.8%, 40.4%, and 78.9% (p < 0.001) and an area under the curve of 82.5%. CONCLUSION: In this validated model, lateral meniscus extrusion, K-L Grade 4, SIFK on MFC, lateral meniscus root tear, and medial meniscus extrusion were the most important factors in predicting progression to arthroplasty (in that order). This model assists in patient treatment and counseling in providing prognostic information based on patient-specific risk factors by classifying them into a low-, medium-, and high-risk categories. This model can be used both by medical professionals treating musculoskeletal injuries in guiding patient decision making. LEVEL OF EVIDENCE: Level III.

Systematic Review of Medial Patellofemoral Ligament Reconstruction Techniques: Comparison of Patellar Bone Socket and Cortical Surface Fixation Techniques.

PURPOSE: To compare patellar bone socket and cortical surface fixation techniques for isolated medial patellofemoral ligament (MPFL) reconstruction and determine whether there was a difference in (1) complication rates, including fracture of the patella; (2) redislocation rates; or (3) patient-reported outcomes. METHODS: A literature search was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included patients who underwent isolated MPFL reconstruction for recurrent patellar instability. Patients with confirmed concomitant or prior ipsilateral knee procedures, multiligament injury, or less than 3 months of follow-up were excluded. Risk-of-bias assessment was performed using the Methodological Index for Non-randomized Studies (MINORS) system. Studies were classified by surgical technique (patellar bone socket group [group S] vs cortical fixation group [group F]), and complications, redislocations, and patient-reported outcomes were collected. RESULTS: A total of 29 studies yielded 981 patients with MPFL reconstruction for inclusion. Of the patients, 620 underwent a patellar bone socket technique and 361 underwent a cortical fixation technique. Patients ranged in age from 11 to 68 years. Patellar fracture rates ranged from 0% to 17% in group S and were 0% in all group F studies. Mean Kujala scores ranged from 83.5 to 93.6 in group S and from 84.4 to 94.5 in group F. Mean Lysholm scores ranged from 84.6 to 91.7 in group S and from 83.5 to 95 in group F. Redislocation rates ranged from 0% to 21% in group S and from 0% to 13% in group F. Although heterogeneous in nature, complication rates ranged from 0% to 28% in group S and from 0% to 4% in group F. CONCLUSIONS: MPFL reconstruction techniques with patellar bone sockets showed a larger range of complication rates than cortical fixation techniques, although overall, complications remained uncommon. Clinically, the bone socket group had comparable postoperative redislocation rates and patient outcomes to the group treated with cortical fixation techniques. LEVEL OF EVIDENCE: Level IV, systematic review of Level I through IV studies.