Functional outcome after arthroscopic mosaicplasty for localised osteochondral defects in the knee

Background: Knee injuries are commonly encountered in active sports persons as well as nonathletes, with approximately 60% of patients having cartilage damage with or without associated ligament and meniscal injuries. In this study, we report on the functional outcome of autologous osteochondral grafting in localised cartilage lesions of the knee.

A longitudinal follow-up study was conducted on 50 patients aged between 18-55 years with symptomatic focal cartilage defect in the knee of size less than 2.0 cm² after necessary inclusion/exclusion criteria. Management involved arthroscopic autologous osteochondral grafting. The donor cartilage was from the non-weight-bearing region of the ipsilateral knee. Other associated intra-articular injuries were addressed in the same sitting. The patients were followed up after 6 weeks, 3 months and 6 months and clinical status documented by the Lysholm Knee Function Scale (LKFS).

Most patients were young active males. Clinical presentation involved pain in all participants, followed by joint line tenderness. There was at least one associated injury to other intra-articular structures in 52% of the patients. The commonest associated injury was anterior cruciate ligament (ACL) tear followed by meniscus tear. The mean size of the focal cartilage defect was 1.013 cm², ranging from 0.8 cm² to 1.6 cm². The mean preoperative LKFS was 56.97 ± 1.38 (standard error). There was a statistically (p < 0.001) as well as clinically significant (clinically important difference >13.0 and patient acceptable symptomatic state >70.0) improvement in the mean Lysholm score, which was 70 ± 1.32, 81.3 ± 1.12 and 92.1 ± 1.11 at the end of 6 weeks, 3 months and 6 months respectively. Eighty-four percent of the patients showed excellent functional outcome at 6 months (LKFS >90), whereas 8% and 4% had good and fair outcomes, respectively, at 6 months (LKFS: 70-90). Two patients (4%) who had failed ACL reconstruction had poor outcome (LKFS <70)at 6 months.

Mosaicplasty is an excellent procedure for managing cartilage defects of small to medium sizes, less than 2.0 cm₂. The short-term results are satisfying and can accelerate rehabilitation of sports injuries. It is noteworthy that instability is a contra-indication for the procedure to succeed.