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A New Surgical Approach to Recurrent Dislocation of the Kneecap

Chronic dislocation of the patella (knee cap) requires surgery to stabilize the knee. Many surgical procedures have been done to correct this problem. In this study, surgeons in Japan report on the long-term results of a new realignment technique.

Previous reconstruction methods have resulted in patellofemoral osteoarthritis. This painful condition occurred within 10 years of the operation. This study analyzed the long-term results of a new medial patellofemoral ligament (MPFL) reconstruction method.

The authors described in detail their surgical technique. An artificial ligament made of polyester tape was passed through a tunnel drilled through the patella. The surgeon temorarily attached the ligament to the adductor tubercle. The tension of the ligament was tested.

The ligament was stapled to the bone when full knee range of motion was possible with just the right amount of tension. A thin layer of bone was placed over the staples. Patients were placed in a knee immobilizer. Exercises to strengthen the quadriceps muscle were started right away.

Results were measured by motion and function. Outcomes were reported as excellent, good, fair, or poor. Two of the patients had a poor result because the patella dislocated again. Almost half were classified as excellent. Another 42 per cent were ranked as good. The rest (12 per cent) were placed in the fair category.

The presence of patellofemoral osteoarthritis was minimal when present. Two-thirds of the patients had no sign of arthritis at all. These results show that this method of MPFL reconstruction is safe and effective in preventing recurrent patellar dislocation and progression of arthritis.

The authors suggest that even small errors in graft length and position can make a difference. Without the correct tension, increased force and pressure are placed on the patellofemoral cartilage. Patellofemoral osteoarthritis can be prevented after MPFL reconstruction.

References: Eiki Nomura, MD, PhD, et al. Long-Term Follow-up and Knee Osteoarthritis Change After Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Dislocation. In The American Journal of Sports Medicine. November 2007. Vol. 35. No. 11. Pp. 1851-1858.

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