Coxa vara is a relatively uncommon hip problem, and is defined as any decrease in the angle formed by the femoral neck with the femoral shaft from the normal of 120° to 135°. '"4 It was described by Fiorani in 1881, several years before the discovery of roentgenograms.5 The name coxa vara was coined by Hofmeister in 1894, and congenital coxa vara was described by Kredel in 1896.2'5* Nilsonne in 1924 suggested that failure of ossification of the cartilaginous neck of the femur may be due to an embryonic vascular disorder.5 Barr in 1929 classified coxa vara.7 This classification was enlarged upon by Amstutz and Wilson in 1962.8 Amstutz in 1970 delineated the differences seen in congenital, developmental and acquired coxa vara.9 Roentgenographic examination offers the most readily available means of diagnosing developmental coxa vara. Frequently the overall picture suggests a fracture of the femoral neck with resultant nonunion. There is a depression of the neck of the femur, and the epiphyseal plate is vertical instead of horizontal, usually with a branching at the inferior portion much like an inverted Y enclosing bone between its arms (Fig. 1).
Treatment of developmental coxa vara can only be accomplished surgically. Corrective valgus subtrochanteric or intertrochanteric femoral osteotomy is the treatment of choice and has almost universally proved successful by converting a vertical defect across which sheering forces play into a horizontal defect with compression forces exerted.4"7'9"13 If untreated, the condition proceeds to an established nonunion, usually with resultant incongruity of the hip joint, which ultimately results in arthritis of the hip (Fig. 2).f"8'i:'M'15 The question is when to perform the surgical procedure. The severity of the deformity must be determined in relation to age and in terms of interference with function. Amstutz and Wilson feel that if the neck-shaft angle is 90° or less, or if the linear neck defect is rapidly progressing, operative intervention is indicated regardless of age.8 Otherwise, they prefer to operate around age eight years, recognizing the risk of remodeling with resultant recurrence of the varus deformity. Others believe there is no lower age limit to surgery.4'"' In many instances, the age of treatment is dependent upon the age when the diagnosis is made. Frequently, this is past age six years since the symptoms in early childhood are relatively mild in nature.
Fig. I: Right hip demonstrates the typical diagnostic radiographic findings of developmental coxa vara with heaking of the greater trochanter in a high riding position, varus angle (93°) with an inverted Y triangular epiphyseal vertical fragment, suggesting a nonunion of the neck of the femur.
At the Crippled Children's Hospital in Richmond, Virginia, a total of 15 patients (18 hips) with developmental coxa vara were diagnosed and studied by chart review over a 36 year period from 1940 thru 1976. Followup ranged from two to 13 years (average: six years). There were eight boys and seven girls, of which seven were white and eight black. The age at diagnosis ranged from 14 months to 14 years, the average being six years. Three had bilateral hip involvement, with 11 cases involving the right and seven the left hip. The most common presenting complaints were a short leg with a limp noticed sometime after weight bearing had begun. Pain was a complaint in only two, being mild and intermittent in nature, usually with increased activity. Physical examination revealed shortening of the leg with limitations of abduction, internal rotation, and frequently external rotation was diminished. A positive Trendelenburg sign was recorded in 11 cases. The most consistent radiographic findings were coxa vara with beaking of the greater trochanter and a triangular epiphyseal vertical fragment.
Fig. 2: Right hip in a 14-year-old child treated "conservatively" for seven years. Progressive degenerative changes of the hip joint occurred with a resultant shallow acetabulum and a small irregular head of the femur. This patient had 6.4 cm shortening of the right leg, decreased range of motion of the hip. a positive Trendelenburg sign, and pain with increased act Ml v.
Fig. 3: Comparison of the affected hips pre- and postoperatively showed an increased range of motion in nine of the IJ hi/>s. In all 13. a limp remained postoperatively, though reduced in severity. Elimination of the positive Trendelenburg sign resulted in six of nine cases.
Treatment was instituted at an average age of 6.5 years and consisted of: none (three hips, one patient with bilateral involvement), surgery recommended but refused (two hips), valgus subtrochanteric osteotomy with blade plate fixation (13 hips, two patients with bilateral involvement), and 1 1/2 hip spica cast immobilization for three months (the youngest, age three, and the oldest, 14 years). The surgical technique was that described by Borden.10 In four cases an adductor tenotomy was performed in conjunction with the osteotomy. Preoperative traction was not employed.
One nonoperative patient had bilateral coxa vara and was followed for nine years. It was reported that he had progression of the deformities, walked with a shuffling gait, had decreased range of motion, bilateral positive Trendelenburg signs and some pain. He slowly developed radiographic changes consistent with nonunion and degenerative joint disease bilaterally. Of the 13 hips treated surgically, long term followup through skeletal maturity revealed permanent correction of the varus deformity in 12, with nine of the 13 showing an increased range of motion. In six of the nine hips, a positive Trendelenburg was eliminated (Fig. 3), and in all patients the limp, though reduced, persisted secondary to leg length inequality. The initial varus angle ranged from 52° to 115° (average: 83°) and postoperatively from 125° to 148° (average: 136°) in comparison to the unaffected hip which ranged from 120° to 145° (average: 133°) (Fig. 4). Leg shortening measured 2.5 to 10 cm initially (average: 5 cm) and postoperatively 1.3 to 6.3 cm (average: 3.2 cm).
Residual shortening was treated with a shoe lift or appropriate leg length inequality surgery. There was one failure in a patient who had unsatisfactory placement of the internal fixation device, with subsequent breakage of the plate and recurrence of the varus deformity. Reoperative insertion of a new plate likewise failed, and the patient went on to a nonunion. Subsequent surgical arthrodesis rendered a pain-free hip. An observation of interest and concern was early closure of the proximal capital femoral epiphysis, recorded in five cases postoperatively.
Fig. 4: Comparison of the average preoperative angle of the affected hip of S3" to postoperatively of 136°. The normal hip averaged 133°.
Developmental coxa vara is an infrequent deformity of the femoral neck in children. It is separate from acquired and congenital coxa vara. Children with the developmental form are normal at birth and develop the deformity "idiopathically" later in childhood. Children with the acquired form are normal at birth with the deformity occurring later secondary to such primary conditions as rickets, Gaucher's disease, Legg-Calve-Perthes disease, and the like.8 Children with congenital coxa vara are born with this anomaly and may initially be confused with congenital dislocation of the hip. Roentgenograms differentiate the two readily. Unfortunately, in many instances x-rays are not obtained early and only after weight bearing has begun is the diagnosis made. Then it may be difficult to distinguish between the congenital and developmental forms. A review of records at a busy orthopedic teaching institution revealed only 15 patients (18 hips) with this entity diagnosed over a 36 year period.
Pain usually is not a significant complaint unless the condition goes untreated into late childhood, when degenerative arthritis can occur. Findings on examination reveal limitation of motion, especially abduction and internal rotation. A positive Trendelenburg sign is often present. Roentgenograms of the hip confirm the diagnosis. Treatment is surgical with the aim of correcting the varus deformity. This is best accomplished with a valgus subtrochanteric or intertrochanteric osteotomy. This should be performed at an early age, soon after the diagnosis has been established, so as to get good correction and to prevent further progression of the deformity. Wide abduction of the distal limb is mandatory to obtain an increased valgus angle of the femoral neck and gain maximum length for the already shortened extremity. In addition, hip mechanics will be improved by lengthening the lateral lever arm and thus frequently reversing the abductor lurch (Fig. 5).
A notable finding was premature closure of the proximal capital femoral epiphyseal plate occurring postoperatively in five of the 13 cases (three girls and two boys). This was noted VA to 3 years postoperatively. The cause for this early closure is uncertain.4'8-10 No relationship between premature closure and patient age existed except all children so affected were 10 years of age or under (range: 6-10 years) at the time of corrective surgery. No correlation was found between early closure and degree of varus deformity or amount of valgus correction obtained at surgery. The only common denominator was that all five children were black; however, in no instance was chondrolysis evident, either clinically or by roentgenograms (Table 1). Some authors have stated that premature closure of the capital femoral epiphysis may be a natural result of the disease process itself;8'9 however, review of the literature fails to substantiate this observation, as in most cases of untreated developmental coxa vara, the deformity progresses to what appears to be a nonunion of the femoral neck rather than early closure of the epiphyseal plate. This was a consistent finding in five nonsurgical cases followed in this series (Fig. 6). It did not seem to matter whether the internal fixation device was near the epiphyseal plate (one case) or not (four cases) as premature closure still occurred (Fig. 7). Canale noted premature closure of the proximal femoral epiphyseal plate in a series of children treated for fractures of the neck and intertrochanteric regions of the hip.17 While proximal femoral epiphyseal plate closure may be unavoidable, it deserves careful pre- and interoperative attention. Consideration should be given to traction on the affected limb prior to surgery, to relax the supporting structures of the hip. An adductor tenotomy4'9 performed in conjunction with the valgus osteotomy may be helpful in decreasing the pressure exerted on the hip and epiphyseal plate while helping to increase the maximum abduction gained. In addition, the internai fixation device should not violate the epiphyseal plate at the time of insertion. If the phenomenon of early closure of the proximal femoral epiphysis can be prevented, then the result should be less leg length inequality than exists already in the shortened extremity.18
Fig. 5 A: Seven-year-old black girl with 93° of varus of the right hip, 6.8 cm shortening of the right leg with a painless limp, and limitation of abduction and internal rotation with a positive Trendelenburg sign.
Fig. SB: Interoperative film demonstrates subtrochanteric osteotomy with blade-plate fixation. Note wide abduction of the distal limb and that bladeplate is not near the proximal femoral epiphyseal plate.
Fig. SC: Three and a half years postsurgery there is a valgus angle of i40°. 3.8 cm shortening of the right ieg with a full range of motion of the hip. pain/ess ¿imp and negative Trendelenburg sign. The capital femoral epiphysis remains open.
Developmental coxa Vara is an infrequent deformity of the femoral neck in children. A 36 year review of charts from 1940 thru 1976 at a busy children's orthopedic hospital revealed only 18 cases diagnosed.
PREMATURE CLOSURE PROXIMAL FEMORAL EPIPHYSEAL PLATE
Fig. 6: Right hip, an untreated developmental coxa vara, demonstrates the typical consistent radiographic findings of a varus angle (52°) and what appears to be an old neck fracture with a persistent nonunion.
Roentgenograms of the hip are diagnostic.
Treatment is surgical to correct the varus deformity. This is best accomplished by valgus subtrochanteric or intertrochanteric osteotomy at an early age before the deformity progresses. Maximum abduction of the distal limb should be obtained at surgery to increase the neck-shaft angle to 135° or more; to increase leg length and decrease severity of the limp; and to improve the abductor system biomechanically, resulting in an increased range of motion of the hip and decrease in the abductor lurch.
Early closure of the proximal capital femoral epiphysis is a notable finding not infrequently seen postsurgically, possibly contributing to further leg shortening in the already short extremity. This may be prevented by careful preoperative planning and meticulous interoperative technique.
Fig. 7 A: Right hip in a nine-year-old black boy with 90° of varus, 2.5 cm shortening of the right leg, limitation of abduction and internal rotation, painless limp and a positive Trendelenburg sign.
Fig. 7 B: Interoperative film demonstrates subtrochanteric osteotomy with blade-plate fixation. Note that the internal fixation device, while near, does not violate the capital femoral epiphysis.
Fig. 7C: One year later the osteotomy is well healed with a valgus angle of 13(F.
Fig. 7D: One and one half years postoperatively (age 10'/; years), premature closure of the proximal femoral epiphysis has occurred. The patient had a full range of motion, a painless limp, and negative Trendelenburg sign. However, there is now 1. 3 cm shortening of the right leg. and it is predictable that additional shortening up to 2.8 cm could occur.
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PREMATURE CLOSURE PROXIMAL FEMORAL EPIPHYSEAL PLATE