Krych, Aaron J

Purpose To determine the rate of return of young amateur athletes to sport after hip arthroscopy, their clinical outcomes, and pathologic risk factors for worse outcomes 2 years after surgery. Methods This study included all patients between age 13 and 23 who participated in a sport prior to surgery with intent to return who underwent hip arthroscopy after failure of comprehensive nonoperative management for whom 2‐year outcome scores were available. Outcomes collected retrospectively included modified Harris Hip Score (mHHS) and the Hip Outcome Scores (HOS) subscales for activities of daily living (ADL) and sport (HOS Sport). In addition, sport played, return to sport rates, and Tegner Scores were measured preinjury and postoperatively. Descriptive statistics were used to present demographic data. A priori analysis was used to determine the sample size needed to show minimal clinically important differences for mHHS, HOS ADL, and HOS Sport. Results The study population included 50 patients with a mean age of 17.8 years. Athletes returned to sport at a rate of 92% (46/50). At a mean follow‐up of 34 months, the mean mHHS, HOS ADL, and HOS Sport outcome scores were 85, 91, and 80 for the entire study group; 87, 92, and 84 for the group that returned to sport; and 67, 82, and 41 for the group that did not return to sport, respectively. Median preinjury and postoperative Tegner levels were 8 and 7, respectively. Labral takedown and reattachment was associated with lower HOS ADL ( P = .01) and HOS Sport scores ( P = .02). Conclusions Athletes returned to sport at a high rate (92%; 46/50) after hip arthroscopy and perform activities at near preinjury levels. In this group of athletes, arthroscopic labral repair with chondrolabral preservation, which reflected less severe chondrolabral pathology, performed better than labral repair with takedown and reattachment. Level of Evidence Level IV, therapeutic case series.

Background: Previous studies have reported variable rates of recurrent lateral patellar instability mainly because of limited cohort sizes. In addition, there is currently a lack of information on contralateral patellar instability. Purpose: To evaluate the rate of recurrent ipsilateral patellar dislocations and contralateral patellar dislocations after a first-time lateral patellar dislocation. Additionally, risk factors associated with recurrent dislocations (ipsilateral or contralateral) and time to recurrence were investigated. Study Design: Cohort study; Level of evidence, 3. Methods: This population-based study included 584 patients with a first-time lateral patellar dislocation occurring between 1990 and 2010. A retrospective review was conducted to gather information about the injury, subsequent dislocations (ipsilateral or contralateral), and structural characteristics including trochlear dysplasia, patella alta, and tibial tubercle to trochlear groove (TT-TG) distance. Risk factors were assessed to delineate associations with subsequent dislocations and time to recurrence. Results: At a mean follow-up of 12.4 years, 173 patients had ipsilateral recurrence, and 25 patients had a subsequent contralateral dislocation. At 20 years, the cumulative incidence of ipsilateral recurrence was 36.0%, while the cumulative incidence of contralateral dislocations was 5.4%. Trochlear dysplasia (odds ratio [OR], 18.1), patella alta (OR, 10.4), age <18 years at the time of the first dislocation (OR, 2.4), elevated TT-TG distance (OR, 2.1), and female sex (OR, 1.5) were associated with recurrent ipsilateral dislocations. Time to recurrence was significantly decreased in patients with trochlear dysplasia (23.0 months earlier time to recurrence; P < .001), elevated TT-TG distance (18.5 months; P < .001), patella alta (16.4 months; P = .001), and age <18 years at the time of the first dislocation (15.4 months; P < .001). Risk factors for subsequent contralateral dislocations included patella alta and trochlear dysplasia. Conclusion: At 20 years after a first-time lateral patellar dislocation, the cumulative incidence of recurrent ipsilateral patellar dislocations was 36.0%, compared with 5.4% for contralateral dislocations. Trochlear dysplasia, elevated TT-TG distance, patella alta, age <18 years at the time of the first dislocation, and female sex were associated with ipsilateral recurrence. Trochlear dysplasia, elevated TT-TG distance, patella alta, and age <18 years at the time of the first dislocation were predictive of a statistically significant decrease in time to recurrence.

Abstract The meniscal roots are critical in maintaining the normal shock absorbing function of the meniscus. If a meniscal root tear is left untreated, meniscal extrusion can occur rendering the meniscus nonfunctional resulting in degenerative arthritis. Two main repair techniques are described: (1) suture anchors (direct fixation) and (2) sutures pulled through a tibial tunnel (indirect fixation). Meniscal root repair using a suture anchor technique is technically challenging requiring a posterior portal and a curved suture passing device that can be difficult to manipulate within the knee. We present a technique for posterior medial meniscus root repair using 3 sutures (1 leader, 2 cinch), standard arthroscopy portals, and transtibial fixation. Overall, this technique simplifies a challenging procedure and allows for familiarity and efficiency. Technique Video video See video under supplementary data.

Background: Osteochondritis dissecans (OCD) is a disorder of subchondral bone that causes adverse effects on the overlying cartilage and commonly affects the knee. The incidence of OCD and its long-term effect on the knee joint are controversial. Hypothesis/Purpose: The purpose of this study was to (1) evaluate the rate of osteoarthritis and knee arthroplasty in a population-based cohort of patients with OCD lesions treated operatively and (2) evaluate factors that may predispose patients to knee osteoarthritis and arthroplasty. The investigators hypothesized that OCD lesions diagnosed after skeletal maturity and treatment with fragment excision would be predictive of a diagnosis of osteoarthritis. Study Design: Cohort study; Level of evidence, 3. Methods: The investigators identified 221 patients (mean ± SD age, 26.1 ± 13.6 years) with OCD lesions treated operatively between 1976 and 2010 and followed for 16.3 ± 11.4 years (mean ± SD) from diagnosis. Information related to the diagnosis, laterality of lesion, details of treatment, and progression to osteoarthritis was obtained from the medical record. Surgical treatment was classified as fragment excision, fragment preservation (lesion drilling and/or fragment fixation), or chondral defect grafting (osteochondral allograft or autograft). Factors predictive of osteoarthritis and arthroplasty were examined. Results: There were 134 patients in the fragment excision group, 78 patients in the fragment preservation group, and 9 patients in the chondral defect grafting group. In the fragment excision group, the cumulative incidence of osteoarthritis was 12.0% at 5 years, 17.0% at 10 years, 26.0% at 15 years, 39.0% at 20 years, and 70% at 30 years. The cumulative incidence of arthroplasty was 2.0% at 5 years, 4.0% at 10 years, 4.0% at 15 years, 10.0% at 20 years, and 32.0% at 30 years. In the fragment preservation group, the cumulative incidence of osteoarthritis was 3.0% at 5 years, 7.0% at 10 years, 16.0% at 15 years, 25.0% at 20 years, and 51% at 30 years. The cumulative incidence of arthroplasty was 0.0% at 5 years, 0.0% at 10 years, 3.0% at 15 years, 6.0% at 20 years, and 11.0% at 30 years. No patients in the chondral defect grafting group developed osteoarthritis or underwent arthroplasty. Body mass index (BMI) greater than 25 kg/m 2 (hazard ratio [HR] 3.3; 95% CI, 1.6-7.0), older age at diagnosis (HR 4.9; 95% CI, 1.8-17.3), and fragment excision (HR 2.3; 95% CI, 1.2-4.6) were predictive of osteoarthritis. Conclusion: OCD patients treated with fragment excision have a high rate of osteoarthritis and knee arthroplasty at long-term follow-up. In contrast, patients treated with fragment preservation or chondral defect grafting have lower rates of osteoarthritis and arthroplasty. BMI greater than 25 kg/m 2 , older age at diagnosis, and fragment excision were predictive of osteoarthritis.

Background: The rate of patellofemoral arthritis after lateral patellar dislocation is unknown. Purpose/Hypothesis: The purpose of this study was to compare the risk of patellofemoral arthritis and knee arthroplasty between patients who experienced a lateral patellar dislocation and matched individuals without a patellar dislocation. Additionally, factors predictive of arthritis after patellar dislocation were examined. The hypothesis was that the rate of arthritis is likely higher among patients who experience a patellar dislocation compared with those who do not. Study Design: Cohort study; Level of evidence, 3. Methods: In this study, 609 patients who had a first-time lateral patellar dislocation between 1990 and 2010 were compared with an age- and sex-matched cohort of patients who did not have a patellar dislocation. Medical records were reviewed to collect information related to the initial injury, recurrent dislocation, treatment, and progression to clinically significant patellofemoral arthritis (defined as symptoms with degenerative changes on patellar sunrise radiographs). Factors associated with arthritis (age, sex, recurrence, osteochondral injury, trochlear dysplasia) were examined. Results: At a mean follow-up of 12.3 ± 6.5 years from initial dislocation, 58 patients (9.5%) in the dislocation cohort were diagnosed with patellofemoral arthritis, corresponding to a cumulative incidence of arthritis of 1.2% at 5 years, 2.7% at 10 years, 8.1% at 15 years, 14.8% at 20 years, and 48.9% at 25 years. In the control cohort, 8 patients (1.3%) were diagnosed with arthritis, corresponding to a cumulative incidence of arthritis of 0% at 5 years, 0% at 10 years, 1.3% at 15 years, 2.9% at 20 years, and 8.3% at 25 years. Therefore, patients who experienced a lateral patellar dislocation had a significantly higher risk of developing arthritis (hazard ratio [HR], 7.8; 95% CI, 3.9-17.6; P < .001) than individuals without a patellar dislocation. However, the risk of knee arthroplasty was similar between groups (HR, 2.8; 95% CI, 0.6-19.7; P = .2). Recurrent patellar dislocations (HR, 4.5; 95% CI, 1.6-12.6), osteochondral injury (HR, 11.3; 95% CI, 5.0-26.6), and trochlear dysplasia (HR, 3.6; 95% CI, 1.3-10.0) were associated with arthritis after patellar dislocation. Conclusion: Patellar dislocation is a significant risk factor for patellofemoral arthritis, as nearly half of patients have symptoms and radiographic changes consistent with arthritis at 25 years after lateral patellar dislocation. Osteochondral injury, recurrent patellar instability, and trochlear dysplasia are associated with the development of arthritis.

Background: Second anterior cruciate ligament (ACL) tears after reconstruction occur at a reported rate of 20% to 30%. This high frequency indicates that there may be factors that predispose an athlete to graft failure and ACL tears of the contralateral knee. Purpose: To determine the incidence of second ACL injuries in a geographic population-based cohort over a 10-year observation period. Study Design: Descriptive epidemiological study. Methods: International Classification of Diseases, 9th Revision (ICD-9) codes relevant to the diagnosis of an ACL tear and the procedure code for ACL reconstruction were searched across the Rochester Epidemiology Project, a multidisciplinary county database, between the years of 1990 and 2000. This cohort of patients was tracked for subsequent ACL injuries through December 31, 2015. The authors identified 1041 patients with acute, isolated ACL tears. These patients were stratified by primary and secondary tears, sex, age, activity level, side of injury, sex by side of injury, and graft type. Results: Of the 1041 unique patients with a diagnosed ACL tear in Olmsted County, Minnesota, from 1990 to 2000, there were 66 (6.0%) second ACL tears; 66.7% of these tears occurred on the contralateral side. A second ACL injury was influenced by graft type ( P < .0001), election of ACL reconstruction ( P = .0060), and sex by side of injury ( P = .0072). Nonparametric analysis of graft disruption by graft type demonstrated a higher prevalence of second ACL tears with allografts compared with hamstring ( P = .0499) or patellar tendon autografts ( P = .0012). Conclusion: The incidence of second ACL tears in this population-based cohort was 6.0%, with 66.7% of these tears occurring on the contralateral side from the original injury. There was a high population incidence of second ACL injuries in female patients younger than age 20 years. The utilization of patellar tendon autografts significantly reduced the risk of second ACL injuries compared with allografts or hamstring autografts in this cohort.

Background: Quantitative magnetic resonance (qMR) can be used to measure macromolecules in tissues and is a potential method of observing early cartilage changes in the development of posttraumatic osteoarthritis. Hypothesis/Purpose: We hypothesized that specific patient and surgical factors affecting cartilage matrix composition after anterior cruciate ligament (ACL) reconstruction (ACLR) can be detected using T1ρ and T2 relaxation times. Our purpose was to demonstrate this ability in a multicenter feasibility study. Study Design: Case series; Level of evidence, 4. Methods: A total of 54 patients who underwent ACLR underwent bilateral MRI at baseline before surgery and 6 months postoperatively. Operative findings were recorded. T1ρ and T2 relaxation times were calculated for 6 cartilage regions: the medial femur, lateral femur, medial tibia, lateral tibia, patella, and trochlea. A paired t test compared relaxation times at baseline and 6 months, univariate regression identified regions that influenced patient-reported outcome measures, and analysis of covariance was used to determine the surgical factors that resulted in elevated relaxation times at 6 months. Results: The injured knee had significantly prolonged T1ρ and T2 relaxation times in the tibiofemoral compartment at baseline and 6 months but had shorter values in the patellofemoral compartment compared with the uninjured knee. Prolonged T1ρ and T2 times at 6 months were noted for both the injured and uninjured knees. At 6 months, prolongation of T1ρ and T2 times in the tibial region was associated with lower patient-reported outcome measures. ACLR performed within 30 days of injury had significantly shorter T1ρ times in the tibial regions, and lateral meniscal tears treated with repair had significantly shorter T1ρ times than those treated with excision. Conclusion: Prolonged relaxation times in multiple regions demonstrate how the injury affects the entire joint after an ACL tear. Changes observed in the uninjured knee may be caused by increased loading during rehabilitation, especially in the patellofemoral articular cartilage and distal femur. Relaxation times in the tibial regions may be predictive of patient symptoms at 6 months. These same regions are affected by surgical timing as early as 30 days after injury, but this may partially be reflective of the severity of the preoperative injury and the choice of treatment of meniscal tears.

Background: The cases of patients with medial compartment osteoarthritis who were ≤55 years old and had a proximal tibial osteotomy (PTO) or medial unicompartmental knee arthroplasty (UKA) were compared. Outcomes included postoperative activity level, function, and survivorship free of revision to total knee arthroplasty. Methods: Between 1998 and 2013, data were available for 240 patients between 18 and 55 years old with medial compartment arthritis and varus malalignment who were treated either with PTO (57 patients) or with UKA (183 patients). The mean age was 42.7 years for the 57 patients (41 men and 16 women) in the PTO group versus 49.2 years for the 183 patients (82 men and 101 women) in the UKA group. The Tegner activity level and Lysholm knee scores were evaluated at 3 months and at 1, 2, and 5 years postoperatively as well as at the time of the final follow-up. The end point for survival was defined as revision to total knee arthroplasty. A Wilcoxon rank-sum test was used to evaluate the difference between the groups with respect to the Tegner and Lysholm scores at the respective follow-up intervals. Multivariate regression was used to assess potential confounders. Results: Preoperatively, the PTO and UKA groups had similar Tegner (3.0 ± 1.3 and 2.6 ± 0.09, respectively) and Lysholm scores (69.5 ± 7.3 and 71.6 ± 5.4). Postoperatively, the UKA group had significantly superior mean Tegner scores compared with the PTO group at 3 months (3.82 and 2.02, respectively), at 2 years (4.33 and 3.75), and at the time of the final follow-up (4.48 and 3.08), while the Lysholm scores were higher at 3 months (88.0 and 76.3) and at the final follow-up (90.0 and 80.2) (p < 0.01 for all). Multivariate analysis showed UKA to be an independent predictor of activity level at 3 months, 1 year, and 2 years, as well as at the final follow-up. The survivorship was 77% in the PTO group at an average of 7.2 years and 94% in the UKA group at an average of 5.8 years (p < 0.01). The average time to failure was 98 months (range, 38 to 169 months) in the PTO group and 42 months (range, 2 to 123 months) in the UKA group (p < 0.01). Conclusions: In this comparative cohort study of young patients with isolated unicompartmental arthritis, those treated with UKA reached a higher level of activity early after surgery and it persisted at mid-term follow-up. The UKA group had earlier, but less frequent, revision to total knee arthroplasty. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

AbstractAdipose-derived mesenchymal stem cells (AMSCs) offer potential as a therapeutic option for clinical applications in musculoskeletal regenerative medicine because of their immunomodulatory functions and capacity for trilineage differentiation. In preparation for a phase I clinical trial using AMSCs to treat patients with osteoarthritis, we carried out preclinical studies to assess the safety of human AMSCs within the intra-articular joint space. Culture-expanded human AMSCs grown in human platelet-lysate were delivered via intra-articular injections into normal healthy rabbit knees and knees at risk for the development of osteoarthritis after bilateral medial anterior hemimeniscectomy. Treatment outcomes and safety were evaluated by assessing the general health, function, and behavior of the animals. Joint tissues were analyzed by x-ray, magnetic resonance imaging, and histopathology. Intra-articular AMSC therapy was well tolerated in this study. We did not observe adverse systemic reactions, nor did we find evidence of damage to intra-articular joint tissues. Thus, the data generated in this study show a favorable safety profile for AMSCs within the joint space in support of a phase I clinical trial evaluating the clinical utility of AMSCs to treat osteoarthritis.

Purpose To compare microfracture (MFX) and osteochondral autograft transfer (OAT) surgical techniques to determine (1) postoperative activity level, (2) subjective patient outcomes, (3) failure rates, and (4) assess if any lesion characteristics favored one technique over the other. Methods A comprehensive review of literature was performed of all studies comparing MFX and OAT. Studies included were all prospective studies that reported on activity‐based outcome measures such as Tegner activity scores and subjective outcomes such as the International Knee Documentation Committee score. Failure rates, as determined by the publishing authors, were recorded for each study. Meta‐analyses were conducted using a random‐effects model. Paired standardized mean differences (Hedges's g to account for small sample bias) were used for continuous outcome measures, and risk ratios (Mantel‐Haenszel method for small sample bias) for dichotomous outcome measures. Results Six prospective studies satisfied the eligibility criteria and included 249 patients (186 male, 120 female) with an average age of 26.4 years and follow‐up of 67.2 months. Tegner scores were superior in patients treated with OAT compared with MFX (ΔOAT‐MFX for pre‐post scores = 0.94 Tegner points, standardized mean difference [SMD] = 0.469, P = .005). Failure rates of MFX were higher than OAT (OAT = 11%, MFX = 32%, risk ratio = 2.42, P < .036). OAT was superior to MFX at 3 years in relation to subjective outcome scores (SMD = 0.404, P = .008). When assessing OAT lesions larger than 3 cm 2 , OAT was superior to MFX with respect to activity level (SMD = 0.506, P = .001). Conclusions OAT may achieve higher activity levels and lower risk of failure when compared with MFX for cartilage lesions greater than 3 cm 2 in the knee, although there was no significant difference for lesions less than 3 cm 2 at midterm. However, because of variability in patient‐specific factors such as age, preinjury activity level, lesion location and size, the superiority of OAT over MFX cannot be generalized to all patient populations and therefore requires individualized patient care. Level of Evidence Level II, meta‐analysis of Level I and II studies.