[Reconstruction of quadriceps femoris muscle function with muscle transfer]

Femoral nerve palsy, mostly of iatrogen cause, leads to paresis of quadriceps muscle with complete loss of knee extension. Therapeutical options include neurolysis, nerve reconstruction or functional muscle transplantations. Another concept is the transfer of hamstring muscles as described in post polio surgery. We describe our experience of biceps femoris and semitendinosus muscle transfer for reconstruction of knee extension. From 2003 to 2007 seven patients (mean age 43) with complete loss of knee extension after femoral nerve lesion were treated. Nerve palsy was caused by direct lesion, traction, hematoma after collapse, lesion of lumbosacral plexus and an unclear muscle dystrophy. Indication for muscle transfer was due to long standing muscle paresis. All patients received a transfer of biceps femoris and semitendinosus muscle/tendon into the quadriceps tendon. Patients were immobilised in a cast for 6 weeks in extended knee position. Weight bearing started after 8 weeks. Operations went uneventfully. All patients were able to extend the knee postoperatively against gravity and were able to climb stairs without help. 4 Patients had complete knee extension, 2 had a lack of 20 degrees , one of 30 degrees. Daily routine was possible in all cases. No instability of knee joints occurred postoperatively. In a nerve lesion close to the muscle a nerve reconstruction should be aimed. If not performed or with unsuccessful outcome, muscle transfer is a good option to restore function. All recent studies describe good to excellent results with stable knees, allowing the patient to manage daily routine without assistance and to climb stairs up and down. Long term complications such as dislocation of patella or genu recurvatum were not observed in our patients. The latter results as typical complication in polio from weakening knee flexion through biceps femoris transfer, if the gastrocnemius muscle is not forceful enough. However in an isolated femoral nerve lesion this will rarely occur.