Initial Outcomes of Single Versus Multiple-Plug Osteochondral Allograft Transplantation for Osteochondral Defects About the Knee: A Matched Cohort Analysis.

PURPOSE: Although several prior studies have described outcomes of OCA transplantation for single osteochondral lesions, a paucity of information exists comparing outcomes of single versus multiple OCA transplants. We aimed to describe initial outcomes of single versus multiple-plug knee OCA transplants at minimum 1-year follow-up. We hypothesized that there would be no difference in patient-reported outcome measures between patients undergoing single versus multiple-plug OCA transplants at minimum 1-year follow-up. METHODS: We retrospectively reviewed prospectively collected data for patients undergoing OCA transplantation for large (>2cm2) osteochondral defects about the knee. Thirty patients with multi-plug (2+) OCA transplants (either single surface using snowman technique or multi-surface) were 1:1 age- and sex-, and BMI-matched to 30 patients with single-plug OCA transplants. PROMs, including IKDC and KOOS subscores, were obtained preoperatively and minimum 1-year postoperatively. Failure was defined as revision OCA or conversion to UKA or TKA. RESULTS: The cohort included 30 females, 31 left knees, average age of 37±10.3 years, and median follow up of 2.0 years [interquartile range: 1.7-2.5 years]. There was a significant increase in PROMs from pre- to postoperative for the entire cohort and the single versus multi-plug subgroups (p<0.01). There was no difference between groups with respect to the percentage of patients who achieved the MCID for each PROM (p>0.05). There were two failures, each in the single plug group, with a mean time to failure of 3.5 years. CONCLUSION: There is no difference in initial outcomes between patients undergoing single versus multi-plug OCA transplant at short-term follow-up. LEVEL OF EVIDENCE: Level IV, case series Keywords: knee, patella; knee, articular cartilage; knee, general.

Risk Factors for Atraumatic Medial Patellar Facet Lesions.

Background: Medial patellar facet lesions have been well-described in the setting of patellar instability. However, relatively little is known about risk factors for atraumatic medial patellar facet lesions. Purpose/Hypothesis: To identify clinical and radiographic risk factors for medial patellar facet lesions in patients without a history of trauma or patellar instability. It was hypothesized that a posterior tibial tubercle relative to the trochlear groove would be a risk factor for atraumatic medial patellar facet lesions. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 37 patients with atraumatic medial patellar facet lesions were matched by age, sex, and body mass index with 37 control patients without a history of patellofemoral dysplasia. Demographic and imaging characteristics were compared between groups. Plain radiography was used to evaluate Wiberg type, and magnetic resonance imaging was used to calculate Caton-Deschamps index, tibial tubercle-trochlear groove distance, trochlear facet asymmetry ratio, patellotrochlear index, sulcus depth, patellar bisect ratio, and tibial tubercle height. Statistically significant variables from univariate analysis were used as inputs to the multivariate regression model to assess independent risk factors. Results: There were no differences between groups with respect to Wiberg type, Caton-Deschamps index, tibial tubercle-trochlear groove distance, sulcus depth, or patellotrochlear index (P > .05 for all). The medial facet lesion group had a larger medial trochlear facet (trochlear facet asymmetry ratio, 0.72 ± 0.11 vs 0.60 ± 0.09; P < .001), a more medial-lying patella in the trochlear groove (patellar bisect ratio, 0.57 ± 0.06 vs 0.55 ± 0.07; P = .035), and a more posterior tibial tubercle relative to the trochlear groove (tibial tubercle height, -3.13 ± 5.21 vs -0.23 ± 5.93 mm; P = .030) compared with the control group. Multivariate regression analysis identified trochlear facet asymmetry and tibial tubercle height as independent risk factors for medial patellar facet lesions (relative risk = 97.3 [95% CI, 14.9-635.1], P < .001 and relative risk = 0.95 [95% CI, 0.92-0.98], P = .004, respectively). Conclusion: A relatively larger medial trochlear facet and a more posterior tibial tubercle relative to the trochlear groove were found to be risk factors for medial patellar facet lesions in patients without a history of trauma or patellar instability.

Increased Host Bone Marrow Edema on 6-Month MRI Is a Risk Factor for Osteochondral Allograft Failure.

PURPOSE: To evaluate the presence of host bone marrow edema (BME) surrounding osteochondral allograft (OCA) plugs on routine 6-month postoperative magnetic resonance imaging (MRI) and to determine whether such BME is correlated with subsequent failure. METHODS: The present study was approved under our institutional review board-approved database (#2020-2123). We included patients who underwent cartilage repair with OCA for focal chondral and osteochondral defects of the distal femur by 2 senior surgeons between January 2016 and May 2021 with minimum 2-year follow-up. OCA is frequently performed with concomitant procedures, and therefore ligament reconstruction, meniscal surgery, and osteotomy were not exclusion criteria. Failure was defined as (1) poor clinical outcome with graft collapse on follow-up MRI or second-look arthroscopy, (2) primary OCA removal or revision, or (3) conversion to unicompartmental or total knee arthroplasty. Routine MRI scans were performed at 6 ± 2 months postoperatively. All postoperative MRI scans were reviewed from our imaging record by 2 blinded fellowship-trained orthopaedic surgeons. Patients were divided for analyses into 2 groups: BME ≥10 cm3 versus BME <10 cm3. RESULTS: Of the 85 patients eligible for the study, 56 patients (30 female, mean age 31.69 ± 11.34 years) had a minimum 2-year follow-up. Nonfailure cases had a mean clinical follow-up of 3.13 ± 0.93 years. The mean time from surgery to failure in our cohort was 1.67 ± 0.91 years. There were 12 (21.4%) patients with BME ≥10 cm³ and 44 (78.6%) patients with BME <10 cm³. No statistically significant differences were found between groups when compared for sex, age, body mass index, OCA size, time to MRI, mean follow-up, number of plugs, graft location, diagnosis, previous surgeries, or concomitant procedures. All OCA failures of the study cohort were in the BME ≥10 cm³ group, representing 50% of this group (P < .001). Kaplan-Meier survival analysis with the log-rank test demonstrated significant difference in survival distributions between groups (P < .001). Patients who ultimately failed had a mean BME volume of 18.49 ± 5.82 cm3, while the nonfailure group had a mean volume of 4.66 ± 4.97 cm3 (P < .001). Cutoff values around 10 cm³ in receiver operating characteristic curve analysis demonstrated 100% sensitivity and close to 90% specificity for OCA failure diagnosis. CONCLUSION: Host BME with a volume greater than 10 cm³ on 6-month postoperative MRI is predictive of an increased subsequent failure rate after OCA transplantation with a failure rate of 50%. LEVEL OF EVIDENCE: Level III, cohort study.

Short-Term Outcomes of Concomitant Patellofemoral Arthroplasty and Medial Patellofemoral Ligament Reconstruction to Treat Concurrent Patellofemoral Arthritis and Patellar Instability.

The purpose of this study was to evaluate the efficacy of combined patellofemoral arthroplasty (PFA) and medial patellofemoral ligament (MPFL) reconstruction in patients with patellofemoral arthritis in the setting of concomitant patellar instability. Patients who underwent single-stage, combined PFA and MPFL reconstruction by a single surgeon at a tertiary-care orthopaedic center between 2016 and 2021 were identified. Postoperative radiographic and clinical outcomes at a minimum of 6 months were recorded using patient-reported outcome measures, including International Knee Documentation Committee (IKDC), Kujala, and VR-12. Early complications and rates of recurrent instability were also recorded. Of the 16 patients who met inclusion and exclusion criteria, 13 patients were available for final follow-up (81%; 51.7 ± 7.2 years, 11 females, 2 males) with a mean clinical follow-up of 1.3 ± 0.5 years (range: 0.5-2.3 years). Patients experienced significant improvements in patellar tilt and multiple patient-reported outcome metrics postoperatively, including IKDC, Kujala, VR-12 Mental Health, and VR-12 Physical Health. At the time of the most recent follow-up, no patient had experienced a postoperative dislocation or subluxation event. The findings suggest that concurrent PFA and MPFL reconstruction are associated with significant improvements in multiple patient-reported outcomes. Further studies are needed to evaluate the duration of clinical benefits achieved with this combined intervention.

Multi-Surface Cartilage Defects about the Knee Treated with Cartilage Restoration Procedures Show Good Outcomes and Survivorship at Minimum 2-Year Follow-Up.

OBJECTIVE: We aimed to evaluate the outcomes, survivorship, and complications following multi-surface cartilage procedures at minimum 2-year follow-up. DESIGN: Patients with either (1) single-surface osteochondral allograft transplantation (OCAT) with third-generation matrix-induced autologous cultured chondrocyte implantation (MACI) or particulated juvenile cartilage implantation (DeNovo), or (2) multiple-surface OCAT ± associated MACI/DeNovo procedures for grade IV chondral or osteochondral defects about the knee with minimum 2-year follow-up were analyzed. Patient-reported outcome measures (PROMs), including International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales, were obtained preoperatively and at minimum 2 years postoperatively. The percentage of patients who met the minimal clinically important difference (MCID) for each PROM was reported. Failure was defined as revision OCAT, conversion to patellofemoral/total/unicompartmental joint arthroplasty, or Arthrosurface HemiCAP placement. RESULTS: Of 257 patients identified, 35 were included. There was a significant increase in IKDC, KOOS-pain, KOOS-symptom, KOOS-sport, and KOOS-quality of life scores from preoperative to postoperative evaluation (P < 0.03 for all). More than 50% of patients met the MCID for each PROM. There were 2 failures, 1 of the patella and 1 of the medial femoral condyle, at 39.7 and 38.6 months postoperatively, respectively. DISCUSSION: Multi-surface cartilage procedures are a safe, efficacious treatment option for multifocal cartilage defects about the knee at short-term follow-up.

Predilection of Patellofemoral Cartilage Lesions in Patients with Posterior Medial Meniscal Root Lesions.

OBJECTIVE: The present study aims to compare the presence and severity of patellofemoral osteoarthritis between patients with root lesions and non-root lesions. DESIGN: A total of 102 patients were included in this study (51 root lesions and 51 non-root lesions). The root lesion cohort was matched to a non-root lesion cohort based on sex, body mass index, and age at the time of surgery. Radiographic evaluation with modified Outerbridge scoring of MRI of the knee was performed to determine the severity of degeneration of the knee joint preoperatively. Mann-Whitney and Independent t tests were used to compare the groups. RESULTS: The root lesion group had statistically greater Outerbridge patella scores (M = 2.45 ± 1.12) and trochlear scores (M = 2.27 ± 1.37) than the non-root lesion patients (M = 1.78 ± 1.30, P = 0.006, and M = 1.55 ± 1.40, P = 0.010, respectively). When using a new scale for grading patellofemoral arthritis, the root lesion group had statistically greater scores (M = 8.33 ± 3.38) than the non-root lesion patients (M = 5.67 ± 3.07) (P < 0.001). CONCLUSION: Patients with root lesions have a greater degree of patellofemoral cartilage lesions than patients without root lesions. The presence of cartilage lesions preoperatively in root lesion patients has presented the question of whether repair is worthwhile or if one should delay surgery until arthroplasty is indicated. Future research should be carried out on outcomes of root repair surgery in patients with patellofemoral cartilage lesions, in addition to considering the patient's age, activity level, and other risk factors.

Tibial Tubercle Osteotomy With Distalization for the Treatment of Patella Alta.

One of the most common osseous abnormalities associated with patellar instability and patellofemoral osteochondral disease is patella alta, characterized by an Insall-Salvati ratio ≥1.2 or a Caton-Deschamps Index ≥1.2. Despite being the most common surgical treatment option for patella alta, tibial tubercle osteotomy with distalization raises concerns due to the complete detachment of the tubercle, which may lead to damage of local vascularity from periosteal detachment and increased mechanical stress at the attachment site. These factors are related to greater risk of complications, such as fractures, loss of fixation, delayed union, or nonunion of the tuberosity. We describe a technique for tibial tubercle osteotomy with distalization that aims to minimize these complications through care with the osteotomy, stabilization, bone cut thickness, and local periosteum.

Establishing minimal detectable change thresholds for the international knee documentation committee and Kujala scores at one and two years after patellofemoral joint arthroplasty.

PURPOSE: To define the minimal detectable change (MDC) for the international knee documentation committee (IKDC) and Kujala scores one and two years after patellofemoral joint arthroplasty (PFA). METHODS: A distribution-based method (one-half the standard deviation of the mean difference between postoperative and preoperative outcome scores) was applied to establish MDC thresholds among 225 patients undergoing primary PFA at a single high-volume musculoskeletal-care center. Stability of change in MDC achievement was explored by quantifying the proportion of achievement at one- and two-year postoperative timepoints. Multivariable logistic regression analysis was performed to explore the association between sociodemographic and operative features on MDC achievement. RESULTS: MDC thresholds for the Kujala score were 10.3 (71.1% achievement) and 10.6 (70.4% achievement) at one- and two years, respectively. The MDC thresholds for the IKDC score were 11.2 (78.1% achievement) and 12.3 (69.0% achievement) at one- and two years, respectively. Predictors of achieving the MDC for the Kujala and IKDC scores at both time points were lower preoperative Kujala and IKDC scores, respectively. Preoperative thresholds of ≤ 24.1 and 7.6 for the Kujala and IKDC scores, respectively, were associated with a 90% MDC achievement probability. When preoperative thresholds approached 64.3 and 48.3 for the Kujala and IKDC, respectively, MDC achievement probability reduced to 50%. CONCLUSION: The MDC thresholds for the Kujala and IKDC scores two years after PFA were 10.6 and 12.3, respectively. Clinically significant health status changes were maintained overall, with a slight decrease in achievement rates between one and two years. MDC achievement was associated with disability at presentation, and several probability-based preoperative thresholds were defined. These findings may assist knee surgeons with patient selection and the decision to proceed with PFA by better understanding the patient-specific propensity for MDC achievement. LEVEL OF EVIDENCE: IV, retrospective case series.

Patellar Tendon Imbrication for the Treatment of Patella Alta in Skeletally Immature Patients.

Patella alta is a major contributor to recurrent patellar instability, which is commonly seen in young athletes. Distalizing tibial tubercle osteotomy has been used for the correction of patella alta and patellar instability, but this procedure is contraindicated in the skeletally immature patient population, as it could lead to growth arrest of the proximal tibial physes. We propose a patellar tendon imbrication technique as a soft-tissue alternative to tibial tubercle osteotomy. When used with concomitant medial patellofemoral ligament reconstruction, we suggest this procedure may prove beneficial for the treatment of patellar instability in skeletally immature patients.