Abstract
Introduction
The management of early OA in young patients with joint preservation techniques utilizing cartilage repair remains challenging and a suitable treatment remains unclear. The management of bipolar chondral lesions in the patello-femoral (PF) and in the tibio-femoral (TF) compartment with cartilage repair is especially troublesome. The purpose of this study was to evaluate the clinical outcomes and survivorship after ACI for the treatment of bipolar chondral lesions in the PF and TF compartment.
Methods
This was an IRB approved, prospectively collected case series, level 4 study. We evaluated 115 patients. 58 patients who had ACI for the treatment of symptomatic bipolar chondral lesions in the PF compartment and 57 in the TF compartment with a minimum 2-year follow up. A single surgeon performed all the surgeries between October 1995 and June 2014. In the PF group, all 58 patients (60 knees; mean age, 36.6 years) were included, and for the TF group one patient did not return for follow-up, 56 patients (58 knees) were included.
For the PF group, an average size of the patella and trochlea lesions were 5.6 ± 2.7 cm2 and 4.2 ± 2.8 cm2, respectively. For the TF group, an average of 3.1 lesions per knee were treated, representing a total surface area of 16.1 cm2 (range, 3.2 – 44.5 cm2) per knee. Patients were evaluated with the modified Cincinnati Knee Rating Scale, Visual Analogue Scale, Western Ontario and McMaster Universities Osteoarthritis Index, and the Short Form 36. Patients also answered questions regarding self-rated knee function and satisfaction with the procedure. Standard radiographs were evaluated for progression of OA.
Results
Patients did well for bipolar ACI in both compartments. In the PF compartment overall, the survival rate was 83% and 79% at 5 and 10 years, respectively. Of the 49 (82%) knees with retained grafts, all functional scores significantly improved postoperatively with a very high satisfaction rate (88%) at a mean of 8.8 years after ACI (range, 2 – 16 years). Outcomes for 11 patients were considered as failures at a mean of 2.9 years.
In the TF group, the overall survival rate was 80% at 5 years and 76% at 10 years. Significantly better survival rate in patients with the use of collagen membrane than periosteum (97% vs. 61% at 5 years, P = 0.0014) was found. Of 46 knees with retained grafts, all functional scores significantly improved postoperatively with a very high satisfaction rate (85%) at a mean of 8.3 years after ACI (range, 2–20 years). Outcomes for 12 patients were considered as failures at a mean of 4.1 years. Of them, 9 patients were converted to a partial or total knee arthroplasty at a mean of 4.4 years. Two patients had revision ACI at 5 and 17 months. The other one patient did not require a revision surgery.
At the most recent follow-up for both groups there was no radiographic progression to OA.
Conclusions
Our study showed that ACI for the treatment of bipolar chondral lesions in the PF and TF compartments provided successful clinical outcomes in patients with retained grafts and could possibly prevent or delay OA progression. The best results in the PF joint are as primary repairs and not after failed osteotomy or cartilage repair with a 91% 10-year survival. Collagen membrane is more encouraging than periosteum for bipolar lesions in both the PF and TF compartments. ACI could be an adequate salvage procedure for bipolar chondral lesions in the TF compartment for the relatively young arthritic patient who wishes to avoid an arthroplasty.
