Surgical Correction Of Proximal Femoral Focal Deficiency

Richard E. King, M.D.

The non-standard prosthesis typically fitted to the patient with uncorrected proximal femoral focal deficiency typically includes a wide-mouthed socket, a platform for support of the foot, and outside knee joints (Fig. 1 and Fig. 2 ). Functionally and cosmetically this prosthesis leaves much to be desired.

At the Georgia Juvenile Amputee Clinic, as at other centers, surgical treatment of a proximal femoral focal deficiency to provide a good skeletal lever for control of a prosthesis is under investigation. Since each case presents unique problems, evaluation and treatment must be on an individual basis.

Contracture Corrected Indirectly

The usual deformity presented is one of external rotation, flexion and abduction of the proximal portion of the femur (Fig. 3 and Fig. 4 ). The surgery performed usually does not require that special attention be directed to these contractures, i.e., surgery directed toward completion and achievement of an intact skeletal lever usually is sufficient to correct the contracture about the hip area.

Minimal Disturbance of Muscles and Nerves

Analysis of the skin, nerves, bone, joint and musculature of a proximal femoral focal deficiency reveals that the surgical procedure to provide a single skeletal lever can be achieved with adequate skin, no disturbance of the nerves or circulation, adequate bone, good joint function, and musculature sufficient to move the skeletal lever.

Enchondral Ossification Stimulated

Additionally, in the usual case of proximal femoral focal deficiency, one is provided with good cartilage in the area of "pseudarthrosis" so that mere realignment in a semblance of weight-bearing will allow the "pseudarthrosis" to awaken from the dormant state and normal enchondral ossification will ensue (Fig. 5 ).

A Recent Case History

P.M., initially seen at age 2 1/2, presented the typical proximal femoral focal deficiency deformity of flexion, external rotation and abduction of hip (Fig. 3 and Fig. 4 ). This patient had never walked, due to lack of stability in the hip area (Fig. 6 ).

First Surgery

Initially, an attempt was made to align the skeletal fragments over an intramedullary rod.

Fig. 7 shows the fragments of the proximal and distal femur fixed over an in-tra-medullary rod, with the rod presented dis tally in the region of the foot.

A knee arthrodesis was performed, concomitant with the realignment of the femoral segments (Fig. 8 ).

Fig. 9 and Fig. 10 show final realignment of knee fusion and pseudarthrosis to make a single skeletal lever.

Second Surgery

Approximately two months later, a disarticulation at the ankle was performed. The knee fusion was solid and the intramedullary rod was removed at the time of the disarticulation (Fig. 11 ). This procedure retains the epiphyses of the distal femur and proximal and distal tibia intact. It is noteworthy that the disarticulation at this age provides a stump end which is level with the opposite knee for cosmetic prosthetic application (Fig. 12 and Fig. 13 ).

With the skeletal lever stabilized, the range of motion and strength available for prosthetic control is quite impressive (Fig. 14 , Fig. 15 and Fig. 16 ).

Current Status

In summary, a case of proximal femoral focal deficiency is presented to illustrate the concept that the area of "pseud-arthrosis" represents normal but disoriented cartilage that awaits realignment in normal weight-bearing position for growth stimulation and eventual ossification. Also, that when an intact skeletal lever is provided, the musculature is adequate for control of a conventional above-knee prosthesis (Fig. 17 and Fig. 18 ).

Case Still Being Followed

Sufficient time has not yet elapsed for proper evaluation of growth at the epiphyses of the distal femur and proximal and distal tibia. The extent of this growth and its effect on prosthetic applications will be the subject of a later report.

Richard E. King, M.D. is associated with the Georgia Juvenile Amputee Clinic Crippled Children's Service Emory University Branch Atlanta, Georgia