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Results of Surgery to Treat Chronic Patellar Dislocation

In a certain group of adults, the patella (knee cap) dislocates every time the knee is bent or flexed. Over time, this causes a condition called chondromalacia. Chondromalacia is a softening and shredding of the cartilage behind the patella. Uneven wear and tear in this area can cause painful knee symptoms.

Surgery may be needed to correct the chronic dislocation problem. But realignment procedures may not be enough when there's chondromalacia present. In this study, surgeons from Taiwan explored the use of several surgical procedures combined together to treat this condition.

Three operations were performed over a period of months to years. The first was a lateral release. The surgeon cut through the connective tissue along the outer edge of the patella.

The second was a medial retinaculum advancement. The connective tissue along the inside edge of the patella was cut and moved. It was sutured (stitched) alongside the patellar tendon.

The final step was an anteromedial tibial tubercle transfer procedure. The tibial tubercle, a bump of bone along the front of the tibia (lower leg bone) just below the patella, was removed and readjusted in location. Together, these operations made it possible to bend the knee past 90-degrees without dislocating.

Everyone wore a knee brace for six weeks after the operation. The brace did not limit motion. Patients used crutches to reduce weight-bearing until healing was well underway. Results were measured using X-rays to look at placement. Tests of knee function were also included.

All patients were able to bend and straighten the knee without further dislocation. X-rays showed major improvement in the angles measured before and after surgery. Function improved dramatically. No one had any further patellar dislocations even with full knee flexion.

References: Hsain-Chung Shen, MD, et al. Combined Proximal and Distal Realignment Procedures to Treat the Habitual Dislocation of the Patella in Adults. In The American Journal of Sports Medicine. December 2007. Vol. 35. No. 12. Pp. 2101-2108.

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