Summary
Autologous bone grafting combined with matrix-associated autologous chondrocyte implantation leads to significant improvements in subjective outcomes and satisfying radiological results, although patients show abnormal postoperative gait patterns.
Abstract
Objectives: The main objective of this study was to examine the patient-reported outcomes, as well as the radiological results, following treatment with a combination of autologous bone grafting and matrix-associated autologous chondrocyte implantation using spheroids (MABCI) for osteochondral defects in the knee. Additionally, the study aimed to assess postoperative gait biomechanics to identify abnormal gait patterns.
Methods
Patient-reported outcomes were evaluated using the IKDC score, Lysholm score, the PROMIS 29 profile, and a questionnaire on the patient's subjective treatment success. Cartilage thickness, T2 relaxation time (T2map), relative perfusion rate measurements and the MOCART2.0 Knee Score were analyzed using 3T magnetic resonance imaging (MRI). Gait biomechanics were assessed with 3D-instrumented gait analysis (Vicon Nexus) and compared to sex, age, and BMI-matched healthy controls.
Results
A total of 35 patients (m/f: 21/14, mean age: 30.9 ±10,2 years; mean BMI 25.3 ±4,8 kg/m) were retrospectively enrolled in this study. The mean chondral lesion size was 4.2 ± 2.4 cm2. Evaluation was performed at a mean 3.6 ±1.9 years of follow-up. All clinical scores showed statistically significant improvement compared to the preoperative condition (Lysholm: 74,3 ±14,1 vs. 64,8 ±17,8, p<0.01; IKDC: 73,1 ±10,1 vs. 56,6 ±17,2, p<0.01; pain intensity PROMIS 29: 2.7 ± 2.0 vs. 5.0 ± 2.5, p<0.01). The analyzed patients reported a high satisfaction rate (94.3%). Self-selected walking speed was significantly lower compared to healthy controls (3.5 ±0.7 km/h vs. 4.2 ±0.6 km/h, p<0,01). During loading response phase, knee flexion was significantly smaller (9.58° ±7.0 vs. 17.7° ±4.6, p<0.01), and knee extension moment was significantly lower (0.1 Nm/kg ±0.2 vs. 0.4 Nm/kg ±0.17, p<0.01) compared to healthy controls. The mean MOCART2.0 score was 61.32 ±13.0. In MOCART2.0 subscores, the volume fill of cartilage defect was 16.1 ±3.7 out of 20 points, and integration into adjacent cartilage was 12.9 ±3.4 out of 15 points. The mean cartilage thickness in the treated defect zone (3.4mm ±0.9 vs. 2.9mm ±0.5, p=0.03) was significant thicker, than reference measurements in not affected areas of the knee. T2map (50.5 ±40.0 vs. 41.3 ±5.4, p=0.9) showed no significant differences from reference measurements. The perfusion measurement of the cartilage transplant showed no significant difference compared to healthy cartilage (1.3 ±0.7 vs. 1.38 ±0.8, p=0.8). In the reconstructed subchondral bone, there was an increased relative perfusion rate compared to healthy bone (3.9 ±2.1 vs. 1.0, p<0.01). A high mean cartilage thickness was correlated with a low pain intensity in the PROMIS 29 profile (R -0.4, p=0.03).
Conclusions
MABCI for treatment of osteochondral defects of the knee led to significant improvements in all subjective outcome measures compared to preoperative levels. However, patients exhibited abnormal gait patterns, including reduced knee flexion and lower knee extension moments during the loading response phase, which may contribute to further cartilage degeneration. Despite these gait abnormalities, the radiological assessments showed promising results, with a satisfactory volume fill of the cartilage defect and successful integration into the surrounding cartilage.