Providing A Single Skeletal Lever In Proximal Femoral Focal Deficiency: A Preliminary Case Report
Richard E. King, M.D.
The aim of surgical treatment of proximal femoral focal deficiency is to provide a good skeletal lever for control of the prosthesis. A previous article1 spelled out the benefits of a single skeletal lever-i.e., relief of contracture, adequate musculature to move the lever, and adequate vascular and nerve supply to muscles and stump. To these must be added pelvi-femoral stability, as demonstrated in the case previously described and in the present case.
It cannot be emphasized too frequently that each individual case requires careful analysis if an appropriate solution to this formidable problem is to be found. Also, the surgeon must be aware that if an acetabulum is present at birth, it will eventually contain elements of a femoral head. Awareness of this developmental sequence will obviate unnecessary attempts at obtaining pelvifemoral stability by bifurcation, osteotomies, bone grafts, etc.2
This article constitutes a preliminary report on an additional case to corroborate the above statements and to provide further evidence in support of our previously expressed belief that realignment of the skeletal parts of a proximal femoral focal deficiency will stimulate endochondral ossification and epiphyseal growth.
P.D. was initially seen shortly after her birth on September 29, 1960, and was followed through the Georgia Crippled Children's Service. The child's thigh had the typical ship's funnel appearance, with the usual flexion, external rotation, and abduction contracture (Fig. 1 ). The patient was fitted with an extension brace, and ambulation was permitted. The child was referred to the Juvenile Amputee Clinic in February 1965, at which time X-rays revealed a type ii (Aitken's classification) proximal femoral focal deficiency. We would describe the deficiency as a severe subtrochanteric coxa vara3 (Fig. 2 ).
In April 1965, an attempt was made to place the sharpened spike of the distal femur into a mortice in the femoral head. At the same time a knee fusion was performed. The sequence of procedures was as follows: A 6 mm intramedullary Kuntscher rod was driven retrograde through the tibia and out of the foot. The femur was then threaded onto this rod to complete the knee fusion. The rod was driven proximally into the femur. At this time the sharp spike of the femur was placed into the mortice in the femoral head. However, the upper end of the femur was bowed and the intramedullary rod came out laterally. Therefore, the entire limb was held in 90 degrees abduction, and the rod was driven into the anterior-inferior spine of the ilium, thus stabilizing the femoral-tibial segment in this position as well as offering a supporting bypass strut to the epiphyseal-diaphyseal fusion (femoral head to femoral shaft). The patient was placed in a double spica cast with the affected extremity in 90 degrees abduction.
Sections from the proximal femur showed viable cartilage (Fig. 3 ), and sections from the epiphysis of the femoral head showed a viable but somewhat disorganized epiphyseal line (Fig. 4 ). On July 7, 1965, the spica was removed and X-rays revealed a thin spicule of bone from femur to femoral head (Fig. 5 ). It was felt that this represented a precarious attachment, and another spica was applied for an additional month. When this was removed on August 11, 1965, X-rays were made in adduction and abduction, and it was believed that the femur and femoral head moved as a single unit.
By February 15, 1966, the patient had been putting some weight on the foot, and X-rays revealed that the thin spicule of bone had hypertrophied and was now the thickness of a thumb (Fig. 6 ). The knee also appeared to be solid. The intramedullary rod was removed, and at the same time a Syme's procedure was performed (Fig. 7 ).
On March 23, 1966, the patient was found to have a stable hip with satisfactory stump abduction, flexion, and extension (Fig. 8, 9 and 10 ). On this date she was fitted with a plastic funnel-shaped socket with an ischial seat, metal hip control, single axis knee, and SACH foot (Fig. 11 ).
The patient received prosthetic training and is now ambulating well. When last seen on July 6, 1966, X-rays revealed further apparent hypertrophy of the proximal femur, with a suggestion of increased growth of the femoral head. The patient had developed an inexplicable line of radiolucency in the femoral shaft (Fig. 12 ). Perhaps this zone represents an area through which bending may occur to cause a subsequent coxa vara. However, if necessary, osteotomy to realign this bending could be performed later and should cause this zone to close.
At present, no further conclusions concerning the status of the epiphyses and the femoral head can be drawn. However, we hope to make these considerations the subject of a later report.
This report considers an attempt at epiphyseal-diaphyseal fusion in a case of proximal femoral focal deficiency and suggests that perhaps the dormant epiphysis of the femoral head will continue to grow if given proper stimulation. Also, one is led to believe that proper realignment of the segments of the proximal femoral focal deficiency will permit endochondral ossification to proceed in a more nearly normal fashion. It will certainly be exciting to see the eventual outcome of this case and to study the effects of the stimulation provided by movement and use.
Richard E. King, M.D. is the Clinic Chief, Amputee Clinic Atlanta Orthopaedic Clinic Atlanta, Georgia
1. Richard E. King, "Surgical Correction of Proximal Femoral Focal Deficiencies," Inter-Clinic Information Bulletin, Vol. IV, No. 10 (August 1965).
2. Sidney Sideman, "Agenesis of Femur: Report of a Case," I, Vol. 40, No. 2 (August 1963).
3. Richard E. King, "Proximal Femoral Focal Deficiencies," Inter-Clinic Information Bulletin, Vol. III, No. 9 (July 1964).