Supracondylar femoral osteotomy for knee flexion contracture in poliomyelitic conditions

Purpose of the study Knee flexion contracture due to quadriceps paralysis i s a major handicap in poliomyelitis patients. The patient has to stabilize the knee with the ipsilateral hand to achieve weight bearing and the deform ed knee precludes use of orthopedic devices. Extension can be achieved with supracondylar femoral osteotomy if the knee flexion contracture is less th an 30 degrees. We assessed functional and anatomic outcome. Material and methods We reviewed the files of 87 patients who had undergone 93 supracondylar femoral osteotomies for knee flexion contracture (6 bilat eral cases); mean age was 18 years and mean flexion was 25 degrees. The sur gical correction was achieved by diaphyseal metaphyseal impaction with rese ction of an anterior wedge and preservation of the posterior component of t he articulation. If some gluteus maximus activity was retained and the tibi otarsal joint was in a slightly equine position, weight bearing in a stable locked position became an automatic postural event even in case of total p aralysis of the quadriceps. Osteotomy was not possible if the contracture f lexion was greater than 30 degrees due to excessive tension on the vaculone rvous bundles. The procedure was equally impossible in children under 12 ye ars of age due to the risk of recurrence subsequent to migration and callus remodeling with bone growth. Results Complete extension of the knee was achieved peroperatively in all c ases. The most serious complications were three cases of septic arthritis t hat led to an irreducible stiff knee. In addition, we had two cases of tran sient paralysis of the common fibular nerve that recovered spontaneously. B one fusion was achieved in all cases within 30 days. Recurrent flexion cont racture was observed in 5 cases and required a revision using the same proc edure in 3 or them. Postoperatively, the amplitude gained in knee extension corresponded to the amplitude lost for flexion. Sixty-three patients were able to walk independently without manual stabilization and a knee extensio n orthesis could be installed for 19 others. Three patients were still unab le to walk despite the correction of the knee flexion contracture due to fa ilure of poorly accepted orthopedic devices. Discussion Several conservative methods (physiotherapy, manipulations, succ essive corrective casts) and surgical procedures (release of posterior soft tissues, Ilizarov technique) have been proposed for the correction of para lytic knee flexion contracture. Supracondylar femoral osteotomy for extensi on can be useful after the end of growth if the flexion contracture remains below 30 degrees. The procedure is simple and morbidity is relatively low compared with the regularly successful results. When the flexion contractur e exceeds 30 degrees, the supracondylar osteotomy cannot be employed due to the risk of stretching the vasculonervous bundles and due to the instabili ty and disorganization of the lower femur. Progressive correction can be pr oposed for these patients: regular monitoring of the neurological and vascu lar situation is required. Functional improvement is considerable after cor rection of knee flexion contracture. The patients can walk more easily, no longer need to stabilize their knee with their hand, and can benefit from o rthopedic devises due to the more favorable biomechanical conditions.