AbstractPurposeThe 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).MethodsAll 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.ResultsThere 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).ConclusionsThis 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 evidenceIV.
Spontaneous Osteonecrosis/Subchondral Insufficiency Fractures of the Knee
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.
Are Baseball Statistics an Appropriate Tool for Assessing Return to Play in Injured Players: An Analysis of Statistically Variability in Healthy Players Using a Machine Learning Approach
Objectives: Traditional pitching statistics (ERA, WHIP, etc) have been used as surrogates for pitcher performance without being validated. Even amongst healthy pitchers, the normal variability of these parameters has not yet been established. The purpose of this study was to determine the normal variability of basic and advanced pitching statistics in non-injured Major League Baseball (MLB) pitchers. It is our hope that this work 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 following injury. Methods: Publicly available data from MLB Statcast and Pitch/Fx databases was used to analyze all non-injured MLB pitchers during 2015 and 2016 seasons who pitcher greater than 100 innings each season without injury. Traditional and advanced baseball pitching statistics were analyzed. The variability of each parameter was assessed by computing coefficient of variation (CV) between individual pitchers and across all pitchers. A CV below 10 is typically indicative of a relatively constant parameter, and parameters with a CV > 10 are generally considered inconsistent and unreliable. Results: A total of 118 pitchers met all inclusion criteria. For each of these healthy pitchers, 38 basic/traditional parameters and 17 advanced parameters were analyzed. Of the traditional pitcher statistics, only 1 (3%) demonstrated a CV value < 10 (average fastball velocity [FBv]; CV 1.5) (Figure 1). In advanced statistics, 9 of 17 (53%) variables demonstrated acceptable consistency as evidenced by a CV value < 10 (Figure 2). Release position from plate (release_pos_y) along with velocity from the plate (vy0) where the two most constant advanced parameters. When separated by pitch type, these two parameters were the most constant (lowest CV) in every pitch type. Conclusion: The validity and variability of baseball statistics as surrogate markers for performance after injury/surgery have not yet been evaluated. It is critical that baseball statistics undergo proper vetting prior to being used to assess recovery. This study reveals average fastball velocity and release position from the plate to be the least variable basic and advanced baseball statistics in MLB pitchers. In total, only 10 of the 55 statistics analyzed demonstrated acceptable consistency and reliability. This study can be further used to determine the minimum time that each of these variables needs to be followed to ensure an appropriate sample size is obtained to detect significant differences in pre- and post- injury performance. [Figure: see text][Figure: see text]
Low Accuracy of Diagnostic Codes to Identify Anterior Cruciate Ligament Tear in Orthopaedic Database Research
Background: Database research is being used in orthopaedic literature with increased regularity. The main limitation of database research is the absence of diagnosis and treatment verification afforded by medical chart review. This absence may limit the accuracy of some conclusions and recommendations produced by database research. Hypothesis/Purpose: The purpose was to describe the accuracy of 1 database (Rochester Epidemiology Project) used in orthopaedic research to detect isolated anterior cruciate ligament (ACL) tears and to discuss the limitations of database research. It was hypothesized that diagnostic codes alone are unlikely to be accurate in identifying patients with ACL tears. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A population-based historical cohort study was performed with the Rochester Epidemiology Project database. All subjects had International Classification of Diseases, Ninth Revision, diagnosis codes consistent with ACL tears between January 1, 1990, and December 31, 2010. The medical records of all subjects were reviewed in detail to confirm the accuracy of diagnosis and gather data on injury type, laterality, associated meniscal injuries, magnetic resonance imaging findings, and treatment details. Results: A total of 3494 patients had codes consistent with ACL tears, and 2288 of them were confirmed through chart review to have an isolated ACL tear (65.5%). Among these were 1841 patients (52.7%) with an ACL tear within 1 year of injury and an additional 447 (12.8%) with an ACL tear >1 year from injury. Thirty-nine patients (1.1%) had a partial ACL tear diagnosed on magnetic resonance imaging, 48 (1.4%) had an isolated posterior cruciate ligament tear, and 22 (0.6%) had a combined ACL–posterior cruciate ligament injury. Twenty-four patients (0.7%) had ACL reconstruction before the study period. The remaining 1073 patients (30.7%) had diagnostic codes consistent with an ACL tear but did not have a cruciate ligament injury. Conclusion: This study demonstrates low accuracy with the use of diagnostic codes alone to identify an ACL tear. Database studies offer unique benefits to the medical literature, but the inherent limitations should be taken into account when these data are used to counsel patients, dictate clinical management, or make health care policy decisions. Information from a health care database is most accurate when accompanied by verification of diagnosis, treatment, and outcomes with medical chart review.
Operative And Non-operative Management Of Osteochondritis Dissecans In The Knee Of Skeletally Immature Patients: Rates Of Persistent Knee Pain, Osteoarthritis, And Arthroplasty At Mean 14- Years Follow-up
Objectives: The purpose of this study was to report long-term follow-up of skeletally immature OCD lesions treated operatively and non-operatively and determine risk factors for persistent knee pain at final follow-up. Methods: A large, geographic database of over 500,000 patients was reviewed in this case series to identify and confirm patients with OCD of the knee. Presenting radiographs and MRI were reviewed. Clinical course including operative management, persistent knee pain, and conversion to TKA were obtained and analyzed through review of clinical and operative notes. Results: 95 skeletally immature patients (70 males, 25 females) with OCD lesions diagnosed at a mean age of 13 years (range: 7-16) were followed for a mean of 14 years (range: 2-40). 53 patients (56%) were treated operatively and 42 patients (44%) were treated non-operatively. At final follow up, 13 patients with a mean age of 30 years noted persistent knee pain, 8 (15%) treated operatively versus 5 (12%) treated non-operatively. Risk factors for knee pain were female gender, patellar lesion location, and unstable lesions (Table 1). Four patients (8%) treated operatively and two (5%) treated non-operatively developed symptomatic osteoarthritis at a mean of 28.6 years following diagnosis. One patient treated operatively and two treated non-operatively converted to TKA at a mean of 37 years following diagnosis. Mean age at TKA was 52 years, significantly younger than that observed for primary TKA at our institution (p = 0.004). Conclusion: Patients with skeletally immature OCD lesions have an estimated 14% rate of persistent knee pain, 6% risk of symptomatic osteoarthritis, and 3% risk of conversion to TKA at a mean of 14 years following time of diagnosis. Female patients, patellar lesions, and unstable lesions demonstrated increased risk of persistent knee pain at final follow-up. Patients with OCD of the knee convert to TKA at a significantly younger age than that of the general primary TKA population. [Table: see text]
Osteochondritis Dissecans in the Knee of Skeletally Immature Patients: Rates of Persistent Pain, Osteoarthritis, and Arthroplasty at Mean 14-Years’ Follow-Up
Objective Osteochondritis dissecans (OCD) is a knee disorder of predominately pediatric populations. Because of low incidence, it has traditionally been difficult to study OCD. The purpose of this study was to report long-term outcomes of skeletally immature OCD lesions and determine risk factors for persistent knee pain at final follow-up. Design A geographic database of more than 500,000 patients was reviewed to identify patients with knee OCD. Clinical course including operative management, persistent knee pain, and total knee arthroplasty (TKA) were analyzed through review of radiographs, magnetic resonance images, and physician notes. Results A total of 95 skeletally immature patients (70 male, 25 female, mean age 12.5 ± 2.0 years) were followed for a mean of 14 years (range, 2-40 years). Fifty-three patients were treated operatively and 42 were treated nonoperatively. At final follow-up, 13 patients noted persistent knee pain, 8 treated operatively versus 5 treated nonoperatively. Risk factors for knee pain were female gender, patellar lesions, and unstable lesions. Four patients (8%) treated operatively and 2 patients (5%) treated nonoperatively developed symptomatic osteoarthritis at a mean of 28.6 years following diagnosis. Three patients underwent TKA at a mean age of 52 years, significantly younger than that observed for primary TKA at our institution ( P = 0.004). Conclusions Skeletally immature OCD patients have promising histories, with an estimated 14% risk of persistent knee pain, 6% symptomatic osteoarthritis, and 3% conversion to TKA at 14 years’ mean follow-up. Females, patellar lesions, and unstable lesions demonstrated increased persistent knee pain risk. Patients with OCD undergo TKA at a significantly younger age than the general population.
Internal Fixation of Unstable Osteochondritis Dissecans: Do Open Growth Plates Improve Healing Rate?
Background: Osteochondritis dissecans (OCD) is a disorder of unknown origin that can affect knees in skeletally mature and immature patients. Surgical management is an important cornerstone of treatment for unstable OCD lesions. Purpose: To determine the (1) healing rate after internal fixation of unstable OCD between skeletally immature and mature knees, (2) risk factors for failure, and (3) patient-reported outcomes among healed patients. Study Design: Cohort study; Level of evidence, 3. Methods: A multicenter retrospective cohort study was conducted with patients who underwent internal fixation of unstable knee OCD lesions from 2000 to 2015. Skeletal immaturity was defined as open or partially open physes. Healing was assessed through clinical findings and imaging. Definitive reoperation for the same OCD lesion was classified as failure. Results: Among 87 patients included, 66 (76%) had healed lesions at ≥2 years postoperatively, while 21 (24%) failed. Skeletal maturity made no significant difference in failure rate (risk ratio, 0.68; 95% CI, 0.29-1.72; P = .40). For skeletally immature patients, lateral versus medial condylar location conferred an increased hazard of 18.2 (95% CI, 1.76-188.07; P < .01). Multivariate analysis factoring in skeletal maturity showed that lateral condylar location was an independent risk factor for failure (hazard ratio, 4.25; 95% CI, 1.47-19.85; P < .01). Mean patient-reported outcome scores (International Knee Documentation Committee [IKDC] and Knee injury and Osteoarthritis Outcome Score [KOOS]) increased significantly after surgery, except the KOOS symptoms score for the skeletally mature group. Final scores (mean ± SD) were as follows at a mean follow-up of 60 months (range, 24-166): IKDC, 83.5 ± 20.2; KOOS pain, 89.7 ± 14.1; KOOS symptoms, 87.4 ± 18.4; KOOS activities of daily living, 93.9 ± 12.7; KOOS sports, 80.7 ± 25.9; KOOS quality of life, 78.9 ± 23.1. Conclusion: Skeletally immature and mature patients heal at comparable rates after internal fixation of OCD lesions, resulting in functional and subjective improvement. Lateral femoral condylar lesion location is an independent risk factor for failure.
Paper #60: Risk Factors And Time To Recurrent Ipsilateral And Contralateral Patellar Dislocation: A Population‐Based Study
Background: First-time lateral patellar dislocation is a common orthopaedic injury. The purposes of this study were to (1) evaluate the incidence of first-time lateral patellar dislocation in a geographically-determined population, (2) report trends over time in the incidence of dislocation, and (3) describe the rate of surgical treatment. Hypothesis: The rate of patellar dislocation is highest among adolescent patients. Study Design: Cohort study. Level of Evidence: Level 3. Methods: The study population included 609 individuals identified through a multidisciplinary geographic cohort county database who were diagnosed with first-episode lateral patellar dislocation between 1990 and 2010. The complete medical records were reviewed to confirm the diagnosis and to evaluate details of injury and treatment. Age- and sex-specific incidence rates were calculated and adjusted to the 2010 US population. Poisson regression analyses were performed to examine incidence trends by age, sex, and calendar period. Results: The overall age- and sex-adjusted annual incidence of patellar dislocation was 23.2 (95% CI, 21.2-24.9) per 100,000 person-years. The annual incidence was similar between male and female patients and highest among adolescents aged 14 to 18 years (147.7/100,000 person-years). The mean age at dislocation was 21.4 ± 9.9 years, and 331 patients (54.4%) were female. During the study period, there was a significant decline in the incidence of patellar dislocation among men aged 19 to 25 years ( P = 0.002) and girls aged 14 to 18 years ( P = 0.025). Eighty patients received surgical treatment during the study period, including 66 patients (10.8%) for recurrent instability and 14 patients (2.3%) for acute osteochondral injury. Conclusion: With an annual incidence of 23.2 per 100,000 person-years, lateral patellar dislocation is a frequently encountered orthopaedic injury. The incidence of dislocation among adolescent patients in this cohort is higher than previously reported. Despite a decrease in the annual incidence of dislocation in adolescent girls, the overall incidence of patellar dislocation remained relatively constant over a 21-year observation period. Clinical Relevance: This study demonstrates that the incidence of patellar dislocation in adolescents is greater than previously reported.