FP3.7 Hip articular cartilage repair with autologous mesenchymal stem cells (MSCs): 4-year results in prospective controlled study

Introduction: Articular cartilage damage in the hip is a challenging problem. Microfractures have been traditionally been used to address chondral defects. Augmentation with cells including bone marrow harvested medenchymal stem cells (MSCs) and/or scaffolds have been described. However, longer term data and controlled studies are limited in literature.

Aims: To establish results of MSCs treatment of ICRS grade 2-4 osteochondral defects in hip arthroscopy patients compared to microfracture, controlling for confounders, at 4 years.

Methods: Study design was that of prospective case-control study. A total of 112 patients undergoing hip arthroscopy for femoroacetabular impingement with grade 2-4 chondral defects and a minimum 4-year follow-up were included. Condral defects were either treated with MSC augmentation (55/112) or with microfracture alone (57/100). Patients with grade-4 defects >3cm2 were excluded. Data were collected pre/per/post-operatively at 6, 26 weeks and then annually. This included demographics, chondral-defect grading, radiographic parameters, modified Harris Hip Score(mHHS), VAS for satisfaction(0-10), Non-Arthritic Hip Score(NAHS) and adverse events. Minimum follow-up was 48-months. Descriptive statistics, t-test for parametric and chi-squared test for non-parametric variables were employed with alpha at 5% and beta at 80%.

Results: Mean age in MSC-group and control-group was 44.2 (21,69) and 43.3(19, 69) respectively. There were ICRS grade-4 defects in 43% and 41% of patients in MSC and control-group. Pre-operative mean scores improved in the MSC-group (mHHS from 63.5 to 87.2 (p<0.001), VAS from median 5 to 9, mean NAHS from 62 to 84 (p=0.003) and in control-group (mHHS from 66.2 to 83, VAS from median 6 to median 8, mean NAHS from 62 to 77(p=0.001). The improvement remained sustained in majority of MSC-group while late deterioration occurred in 20% of control-group. In MSC and control groups the revision hip arthroscopy rate was 3.6% and 14%, and conversion to hip replacement rate 3.6% and 8.7% respectively.

Conclusion: Articular cartilage defect augmentation with MSCs appears to offer safe and effective treatment and results are better sustained than the microfracture control-group at 4 years.