Concomitant anterior medializing osteotomy and MPFL reconstruction improves patellar tilt when compared to MPFL reconstruction alone

More negative sagittal tibial tuberosity-trochlear groove distances are correlated with larger patellofemoral chondral lesion size

PURPOSE

The purpose of this study is to assess the association between sagittal tibial tuberosity-trochlear groove (sTT-TG) distance and patellofemoral chondral lesion size in patients undergoing cartilage restoration procedures.

METHODS

A retrospective cohort analysis of patients who underwent an osteochondral allograft transplantation or matrix-induced autologous chondrocyte implantation in the patellofemoral compartment, from 2010 to 2020, were included if they had patellofemoral high-grade lesions, magnetic resonance imaging (MRI) and minimum 2-year follow-up. The preoperative sTT-TG distance was measured independently on axial T2-weighted MRI sequences by two authors, each at least two weeks apart. Intraoperative lesion size was reported according to operative report measurements by the attending surgeon. An interclass correlation coefficient (ICC) was calculated to assess intra- and inter-rater reliability, and categorical data analysis and linear regression models were used to assess the relationship between sTT-TG and lesion size.

RESULTS

A total of 80 patients (50 females) with a mean age of 31.5 ± 10.4 years, body mass index of 27.0 ± 5.9 kg/m2 and follow-up of 61.5 ± 21.4 months were included. A total of 107 lesions were present: 63 patients with unipolar (patella = 41, trochlea = 22) and 22 with bipolar lesions. The mean MRI defect size was 1.6 ± 1.0 cm2 and the mean intraoperative defect size was 3.8 ± 2.4cm2. Intra- (ICC: 0.99,0.98) and inter-rater reliability (ICC: 0.96) were excellent for both MRI defect size and sTT-TG measurements. The mean sTT-TG was -4.8 ± 4.9 mm and was significantly inversely related to MRI defect size (-0.45, p < 0.01), intraoperative patellar lesion size (-0.32, p = 0.01), total lesion area (-0.22, p = 0.04), but not trochlear lesion size (-0.09, p = 0.56). Multivariable regression demonstrated a more negative sTT-TG remained an independent variable correlated with larger MRI-measured patellofemoral defect sizes and intraoperative patellar lesions.

CONCLUSION

A more negative sTT-TG was an independent variable correlated with larger patellofemoral lesions in patients undergoing patellofemoral cartilage restoration.

LEVEL OF EVIDENCE

Level III, Diagnostic.

Morphological Changes of the Posterior Femoral Condyle After Medial Patellar Retinaculum Plasty in Skeletally Immature Patients With Recurrent Patellar Dislocation and Trochlear Dysplasia

Background

Surgical correction for recurrent patellar dislocation (RPD) can improve femoral trochlear morphology; nonetheless, the effects of surgical correction on femoral condyle morphology are unclear.

Purpose

To investigate the morphological changes in the posterior femoral condyle in skeletally immature patients with RPD and trochlear dysplasia (TD) after surgical correction.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 20 skeletally immature patients with bilateral RPD and TD were included in this study. For each patient, the knee that was dislocated more frequently or had sustained a recent injury was treated with medial patellar retinaculum plasty (group S; n = 20 knees), and the asymptomatic or only occasionally dislocated contralateral knee was treated conservatively (group C; n = 20 knees). The lengths of the anterior medial and lateral femoral condyles and the lengths of the posterior medial and lateral femoral condyles were evaluated preoperatively and at the final follow-up. Trochlear morphological characteristics, tibial tuberosity-trochlear groove distance, and patellar tilt angle were compared between preoperative and final follow-up values with the 2-sample paired Student t test and were compared between groups S and C with the independent-samples t test.

Results

The mean follow-up time was 60.7 ± 4.8 months. No knee in group S experienced a redislocation, whereas 80% (16/20) of knees in group C experienced a dislocation. There were significant group differences in the ratio of the posterior medial femoral condyle (PMFC) to the posterior lateral femoral condyle (PLFC) (group S, 1.08 ± 0.05; group C, 1.14 ± 0.06; P = .042). There was no significant difference in the ratio of the anterior lateral femoral condyle to the anterior medial femoral condyle (group S, 1.16 ± 0.13; group C, 1.18 ± 0.09; P = .635). In group S, all trochlear morphological characteristics and patellofemoral joint characteristics improved compared with preoperatively (P≤ .047 for all). In addition, all values significantly differed between groups S and C at the final follow-up (P≤ .044 for all).

Conclusion

The study findings demonstrated that the morphology of the posterior femoral condyle in skeletally immature patients with bilateral RPD and TD changes after surgical correction, with the PLFC growing faster than the PMFC.