Differential Diagnosis Of An Apparent Proximal Focal Femoral Deficiency: A Case Report

Virginia M. Badger, M.D. Claude N. Lambert, M.D.


Foreword

Proximal femoral focal deficiency (PFFD) is diagnosed on the basis of X-ray findings. Several clinicians have noted, however, that a definitive diagnosis cannot be made until a child is several years old and ossification is more complete than at birth. Few of us have had the opportunity of seeing a newborn infant with accompanying X-rays that would tend to indicate a diagnosis of PFFD and then be able to study the case in depth by both gross and microscopic sections.

Dr. Virginia Badger, our Senior Resident, saw the reported patient in consultation and her interest led her to do a complete analysis, which provided the data for this article.

Claude N. Lambert, M.D. 
Chief, Child Amputee Clinic

The Patient

The patient was a three hour old Negro female weighing 2190 grams. She was seen in Consultation by the Orthopedic Service because of a short right leg.

General History

The mother was a 16-year-old Primigravida. Estimated date of confinement was 2/18/65; labor began on 2/21/65. Length of labor was 12 hours, presentation was cephalic and elective low forceps were applied at delivery. The infant did not cry or breathe spontaneously. Within one minute a slow heart rate was obtained at which time the baby was intubated and oxygen started. The heart rate improved but respiration was irregular. Within 5-10 minutes after birth color was good but the child still had poor muscle tone.

Physical Examination

Head circumference, 32 centimeters; chest circumference, 28.5 centimeters; abdominal circumference, 26.5 centimeters; total length, 48 centimeters. Leg lengths: Thighs: Right, 7.5 centimeters; left, 10 centimeters. Legs: Right, 10 centimeters; left, 10.5 centimeters. Feet: Right, 7 centimeters; left, 7.2 centimeters.

The infant was a well-developed apathetic female with good color and fair muscle tone by one hour post-partum. For about three hours, respirations were regular with some expiratory sighing, then became irregular.

There was no caput succedaneum or cephalhematoma. The eyes were open and staring and had conjugate movements. Coarse rhonchi were evident throughout both fields of the lungs. Heart tones were good at 120/ minute. The abdomen was flat and no organomegaly was present.

Musculoskeletal examination: The upper extremities were symmetrically well developed. The right lower extremity measured 17.5 centimeters, the left 20.5 centimeters (Fig. 1 and Fig. 2 ). Full range of motion was present in the left hip, knee, and ankle; also the right knee and ankle. The right hip motions measured: Flexion/Extension: 120°/-20°; Internal rotation/External rotation: 10°/l5°. In testing the range of motion of the right hip, a palpable click was noted. Rotation of the right femoral head under the inguinal ligament could not be felt under the examining finger but the left was easily palpable. The vascular and nerve supplies of the lower extremities were intact. Good toe grasp was present bilaterally. The Moro reflex was poor but the sucking reflex was good.

Hospital Course

Within the first eight hours after delivery the patient developed seizure-like activity, tonic-clonic movements of the individual extremities, and extension of the entire body. Her breathing remained irregular. By nine hours post-partum the patient had developed hemorrhage of the right bulbar conjunctiva, especially over the cornea. A lumbar puncture was attempted but was unsuccessful. The infant was kept in an isolette until she expired at 12 hours after birth.

X-Ray Findings

Pertinent to this discussion are the findings concerning the right leg (Fig.3 and Fig.4 ). The right femur was shorter than the left. The right tibia was also short and the right fibula absent. The bony structure of the feet was normal except for delayed ossification of the right talus. A defect of the proximal end of the right femur was evident - proximal fragment measuring two centimeters being separated from the distal shaft by a radiolucent line. The angulation of the proximal fragment was 100 degrees. The distal femoral epiphysis was ossified on the left, but not on the right.

Initial diagnosis: (1) Right proximal femoral focal deficiency; possible congenital coxa vara; (2) Absent right fibula; (3) Delayed ossification of right distal femoral epiphysis and talus.

Postmortem Examination

No positive external findings were apparent except for the short right leg. On removal of the skin and subcutaneous tissue, a 2 x 3 centimeter bluish discoloration was noted in the proximal portion of the right quadriceps (Fig. 5 ). The muscle, nerve, and vascular supplies of the right thigh were normal. A subtrochanteric enlargement in the proximal femur was noted with a hard palpable mass lateral to a transverse defect in the femoral shaft. Motion was demonstrable at this site. The femoral heads were in the acetabula and external capsular structures were normal (Fig. 6 and Fig. 7 ). The ligamentum teres was absent on the right and the right femoral head and acetabulum were smaller than the left.

The leg musculature, nerve, and vascular supply were normal. In place of the right fibula, there was a dense, soft tissue band to which the lateral leg musculature was attached (Fig. 8and Fig. 9 ). The foot dissections demonstrated normal bone structure (Fig. 10 and Fig. 11 ).

X-rays of the dissected skeleton confirmed the above findings.

The preserved femoral specimen cut longitudinally shows the subtrochanteric lesion and the resultant neck-shaft angular deformity (Fig. 12 ).

Microscopic Study

The lesion in the right proximal femoral shaft showed a well defined fibrous tissue capsule marginally, with nests of cartilage in the proximal and distal articulating surfaces ( Fig. 13 ). The femoral head, neck, and trochanters were normal.

A cross-section of the right fibrous fibula showed a swirl of fibrous tissue with interdigitating muscle fibers forming an "interosseous membrane" ( Fig. 14 ).

Although no gross or X-ray abnormality was noted in the vertebral bodies, members of the Pathology Staff felt that decreased osteoclasis was present (Fig. 15 ).

Summary

The patient was a Negro female born full-term by low forceps delivery. She lived 12 hours and expired of bilateral acute bronchopneumonia and cerebral and cerebellar hemorrhage.

Physical examination revealed a short right leg with a click at the proximal end of the femur on motion of the hip. Gross dissection of the short right lower extremity revealed an old contusion of the proximal portion of the quadriceps muscle and an old fracture in the subtrochanteric region of the femur. The right fibula was absent.

X-rays revealed delayed ossification of the right distal femoral epiphysis and of the right talus; there was a radiolucent defect in the proximal femur on the right, as described above.

Microscopic examination of the right lower extremity revealed a healing fracture of the right femur with secondary coxa vara deformity and a fibrous right fibula. Examination of the vertebral body cellular structure suggested deficient osteoclasis.

Discussion

The opportunity to study the above described deformities in detail is a rare experience.

The original diagnosis of proximal femoral focal deficiency was incorrect, of course, and has been changed to intrauterine fracture in the healing phase with secondary coxa vara. Because of the delayed epiphysial ossification in the right distal femoral epiphysis and the right talus, the question arises as to whether a more generalized bone disease was also present.

According to the classification plan of Coventry and Johnson 1 for patients with congenital absence of the fibula, the patient described here could be classified as a Type III, a patient with no deformity of the foot but with other congenital anomalies. However, according to Frantz and O'Rahilly 2, the fibular lesion should be classified as an intercalary paraxial fibular hemimelia.

Final Diagnosis

  1. Intrauterine fracture, with secondary coxa vara deformity, right femur.
  2. Congenital absence of the right fibula (intercalary paraxial fibular hemimelia).
  3. Delayed ossification of the right distal femoral epiphysis and talus.
  4. Possible generalized bone disease characterized by deficient osteoclasis.

Virginia M. Badger, M.D. and Claude N. Lambert, M.D. are associated Department of Orthopedic Surgery University of Illinois Research and Educational Hospitals

References:
(1) Coventry, M.D. and Johnson, E.W., "Congenital Absence of the Fibula." Journal of Bone and Joint Surgery. 34A: 941-955 1952. 
(2) Frantz, C.H. and O'Rahilly, R., "Congenital Skeletal Limb Deficiencies." Journal of Bone and Joint Surgery. 43A(8): 1205, 1961.