Outcomes of Plug Osteochondral Allograft Transplantation With or Without Concomitant Osteotomy for Cartilage Defects in the Knee: Minimum 2-year Follow-up.

INTRODUCTION

Isolated osteochondral defects of the knee can cause notable pain and disability. Osteochondral allograft (OCA) transplantation using trephined plug grafts is a highly effective, often curative, treatment option. In knees with malalignment into the transplanted compartment, osteotomy can be done concurrently. This study investigates early-to-midterm survivorship, as well as clinical and radiographic outcomes, of plug OCAs with and without concomitant osteotomy in the knee.

METHODS

Plug OCA was done on active, young to middle-aged patients with osteochondral defects ≤4 cm diameter. Prospectively collected data for 102 patients who underwent plug OCA between 2004 and 2020 were reviewed. Survivorship according to Kaplan-Meier analysis was the primary outcome. Failure was defined as conversion to total knee arthroplasty or repeat allograft. Clinical and radiographic outcomes were evaluated using the modified Hospital for Special Surgery (mHSS) score and Kellgren-Lawrence grading.

RESULTS

Eighty-six patients with a mean age of 29 ± 9.7 years (15 to 54) and a mean follow-up of 6.8 ± 3.7 years (2 to 15.9) were studied. Concomitant realignment osteotomy was done in 66 patients (76.7%). Graft survivorship was 100%, 93.8% (95% confidence interval 90.8% to 96.8%), and 89.7% (95% confidence interval 85.6% to 93.8%) at 2, 5, and 10 to 15 years, respectively. Six grafts (7.0%) required knee arthroplasty at a mean of 4.6 ± 1.8 years (2.2 to 7.1). Most common reasons for revision surgeries with graft retention included implant removal (11.6%), débridement (8.1%), and repeat osteotomy (5.8%). The mean mHSS score of 90.8 ± 10.4 (51 to 100) at the final follow-up was significantly higher than the preoperative value of 72.5 ± 12.1 (36 to 90) (P < 0.001). Subgroup analyses revealed a markedly greater risk of failure in grafts with a diameter of 30 mm or larger.

DISCUSSION

Plug OCA with or without concurrent realignment osteotomy resulted in an excellent graft survival of 93% at a mean of 6.8 years, with reliable functional improvement demonstrated by notable improvements in mHSS knee scores.