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Femoral Varus Osteotomy in Legg-Calve-Perthes Disease

Copeliovitch, Leonel MD

Journal of Pediatric Orthopaedics: September 2011 - Volume 31 - Issue - p S189–S191
doi: 10.1097/BPO.0b013e318223b55c
Operative Treatment
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In a preliminary report in 1965, Axer proposed femoral varus derotation osteotomy as an alternative method for treating Legg-Calve-Perthes disease. Thereafter, this became one of the most popular operative methods in the treatment of the disease. A literature analysis of this method experienced during the years is discussed and the investigator's personal approach is described.

Pediatric Orthopedic Unit, Assaf Harofeh Medical Center, Zerifin, Israel

There are no sources of support or funding and the authors declare no conflict of interest.

Reprints: Leonel Copeliovitch, MD, Pediatric Orthopedic Unit, Assaf Harofeh Medical Center, Zerifin 70300, Israel. e-mail: copeliov@asaf.health.gov.il.

In a preliminary report in 1965, Axer1 proposed femoral varus derotation osteotomy as an alternative method for treating Legg-Calve-Perthes disease (LCPD). Thereafter, this became one of the most popular operative methods in the treatment of the disease.

With time, a huge amount of knowledge on the indications and on the limitations of this treatment has accumulated. Nevertheless, it is still one of the most reported and studied methods in the literature.

In 1980, Axer et al2 analyzed a group of children with LCPD who underwent femoral osteotomy to define further those most likely to respond favorably to this procedure. Treatment was directed to removal of the protruded, flattened, and damaged osteochondral head segment, as delineated by arthrography, from the damaging influence of the lateral acetabular lip, and to exposure of the head to the molding influence of the acetabulum during weight bearing and motion. This containment of the head was achieved by using femoral varus-derotation (and sometimes extension) osteotomy. “Reversed” and “open” wedge techniques were also used to minimize limb shortening. Overall results were 83% satisfactory and 17% unsatisfactory according to Mose's criteria.

Surgery is recommended in the early clinical and radiologic stage of the disease, when favorable biological and biomechanical effects may be anticipated. In the late stages of LCPD, osteotomy may be used as a salvage procedure in painful and deformed hips while still maintaining a passive range of motion. An expectant approach can be adopted in children less than 4 years of age, but undue delay in operation, if femoral head protrusion is demonstrated by arthrography, may compromise the final results.

The surgical technique is preceded by arthrography with dynamic examination to find the best containment position. A subtrochanteric osteotomy is performed in an open or closed wedge form, with fixation in an angle that affords best coverage.

In 2003, Joseph et al3 analyzed the outcomes after femoral osteotomy of 97 children and concluded that containment surgery aimed at preventing femoral head deformation in Perthes disease should be performed before the advanced stage of fragmentation. Furthermore, any study on the outcome of containment treatment of Perthes disease should take into consideration the timing of containment as a variable that influences the outcome while interpreting the results. His recommendation is worthwhile “Don't miss the boat.”

In 2004, Herring et al4 enrolled 438 patients with 451 affected hips in a prospective multicenter study in which each investigator applied the same treatment method to each of his or her patients. The 5 treatment groups consisted of no treatment, brace treatment, range-of-motion exercises, femoral osteotomy, and innominate osteotomy. All patients were between 6 and 12 years of age at the onset of the disease and none had had previous treatment. Three hundred and forty-five hips in 337 patients were available for follow-up at skeletal maturity. All hips were classified with the modified lateral pillar classification and the Stulberg system. There were no differences between the hips treated with a femoral varus osteotomy and those treated with an innominate osteotomy. Treatment did not have a significant effect on children who had a chronologic age of 8 years or less or a skeletal age of 6 years or less at the onset of the disease. In the lateral pillar B group and B/C border group, the outcomes of surgical treatment were significantly better than those of nonoperative treatment in children over the age of 8 years at the onset of the disease. Patients who were 8 years old or less at the onset of the disease in lateral pillar group B did equally well with nonoperative and operative treatment. Hips in lateral pillar group C had the least favorable outcomes, with no differences between the operative and nonoperative groups. Their conclusions were that patients who are over the age of 8 years at the time of onset and have a hip in the lateral pillar B group or in the B/C border group have a better outcome with surgical treatment than they do with nonoperative treatment. Group B hips in children who are less than 8 years of age at the time of onset have very favorable outcomes unrelated to treatment, whereas group C hips in children of all ages frequently have poor outcomes, which also seem to be unrelated to treatment.

He did not emphasize containment as a factor in the treatment. In 2005, Joseph et al5 studied how a femoral osteotomy alters the natural evolution of Perthes disease by analyzing records and radiographs of 640 patients with Perthes disease. The data of 314 patients who underwent femoral osteotomy were compared with those of nonoperated patients. It was observed that a varus osteotomy clearly altered the natural evolution of Perthes disease. Of patients who were operated in the stage of avascular necrosis, 34% bypassed the stage of fragmentation. The duration of the disease was shorter in these patients. The duration of the stage of fragmentation was reduced in operated children who had passed through the stage of fragmentation. The extent of femoral head extrusion was minimized at the stage when it was most vulnerable for deformation. Metaphyseal widening and subsequent femoral head enlargement were also minimized in children who underwent a femoral osteotomy. The chances of retaining the sphericity of the femoral head were much higher in those children who underwent a femoral osteotomy. These beneficial effects of a varus osteotomy were most evident when the operation was performed either in the stage of avascular necrosis or in the early stage of fragmentation. He proved the biological effect described by Axer in statistical numbers.

In 2008, Wiig et al6 conducted a nationwide prospective study in Norway designed to determine prognostic factors and to evaluate the outcome of different treatments of Perthes disease. A total of 28 hospitals in Norway were instructed to report all new cases of Perthes disease over a period of 5 years and 425 patients were reported and were followed for 5 years. For patients over 6 years of age at diagnosis and with more than 50% necrosis of the femoral head (152 patients), the surgeons at the different hospitals chose one of 3 methods of treatment: physiotherapy (55 patients), the Scottish Rite abduction orthosis (26), and proximal femoral varus osteotomy (71). The strongest predictor of outcome was femoral head involvement of more or less than 50%, followed by age at diagnosis and the lateral pillar classification. In children over 6 years at diagnosis with more than 50% femoral head necrosis, proximal femoral varus osteotomy yielded a significantly better outcome than orthosis or physiotherapy. They found no difference in outcome after any of the treatments in children under the age of 6 years. They recommended proximal femoral varus osteotomy in children aged 6 years and over at the time of diagnosis with hips having more than 50% femoral head necrosis. They concluded that abduction orthosis should be abandoned in Perthes disease.

In 2008, Beer et al7 published a 33-year follow-up study on femoral osteotomy in Perthes disease. The purpose of this study was to evaluate the correlation between hip deformity at skeletal maturity and degenerative osteoarthritis and to present the long-term results of proximal femoral varus derotational osteotomy in LCPD. The results of 40 patients (43 hips) who underwent proximal femoral varus derotational osteotomy for LCPD between 1959 and 1983 were analyzed in a single long-term follow-up examination. Hips were classified with the Stulberg classification system. Osteoarthritis was evaluated using the Tönnis classification. The long-term outcomes were evaluated after a mean follow-up period of 33 years. When examining the outcome using the Stulberg classification system, there were 8 Stulberg class I hips (19.5%), 15 Stulberg class II hips (36.6%), 8 Stulberg class III hips (19.5%), 9 Stulberg class IV hips (22%), and 1 Stulberg class V hip (2.4%). One patient, who had bilateral LCPD, underwent total hip replacement for osteoarthritis. Seven patients had poor clinical results. The conclusions were that proximal femoral varus derotational osteotomy provides good long-term results for LCPD.

According to the above, it seems that proximal femur varus osteotomy is a good choice in the treatment of LCPD, according to correct indications. Questions to be answered are as follows: Is there a need for rotation and extension, added to varus, for improvement of results? Can trochanteric epiphysiodesis significantly improve the articular trochanteric distance with time after surgery? Can we determine the varus angle beforehand without arthrography? Is shortening due to wedge excision osteotomy a bad thing or will it be useful? Further investigations are needed to solve these issues.

I would like to make some considerations “to take home” about containment, femoral shortening, and abductor insufficiency.

  1. First, we must be able to contain the head of the femur inside the acetabulum, leaving free range of abduction to also afford “dynamic containment.” If this is not possible, we choose another method of coverage of the extruded head, having good experience with the Shelf operation in these cases.
  2. The average varus angle needed is approximately 25 to 35 degrees, which causes a shortening of 1 to 2 cm. Taking into consideration the growth stimulation caused by the osteotomy itself, most of the shortening will be overcome. In 1984, Mirovsky et al8 compared residual shortening of the affected limbs in 55 patients treated by subtrochanteric varus derotation osteotomy with that in 71 patients treated with weight-relieving calipers. They found that the average residual shortening (0.9 cm) was identical in both groups. In most patients, the initial shortening caused by the osteotomy gradually corrected as, over a period of several years, the postosteotomy angle gradually became less varus. Any residual shortening depended principally on the severity of inhibition of endochondral ossification at the proximal femoral growth plate. Less residual shortening was seen in children who were under 7 years of age at the onset of symptoms (under 8 at operation) in whom the open-wedge technique of osteotomy was used and who had good anatomical results. It is possible that temporary shortening has a positive effect by diminishing the pressure over the necrotic head. The subtrochanteric shortening may also improve the advantage of gluteus medius action by weakening the adductors and thus improving the “dynamic containment” of the head.
  3. Abductor insufficiency, worsened by the varus osteotomy, is a real problem that must be solved. It prevents “dynamic containment” of the femoral head and causes Trendelenburg limp.

The gluteus medius weakening leads to a tensor fascia lata “take over” as a main abductor, thus stressing the knee laterally and causing genu valgum in some cases.

Methods to solve the abduction insufficiency problem include physiotherapy, which improves the range of abduction and provides active strengthening of the abductors.

Preventive trochanteric epiphysiodesis is routinely performed in our cases to decrease gluteus medius insufficiency. In later cases, if a round head is achieved and the greater trochanter remains high relative to the femoral head, a distal transfer of the greater trochanter is able to improve limps.

In cases of a remaining elliptical head or “saddle shape” deformity, a valgus osteotomy can improve the range of abduction, together with improvement of the gluteus medius lever arm.

I understand the importance of stage and involvement classifications, according to Catterall, Herring, and Thomson. However, I believe today that extrusion of the femoral head in the fragmentation or even early regeneration stage in a containable head is a “must do” factor, and a varus osteotomy should then be performed.

Figures 1 to 3 are an example of one of our cases, even if it is with short-term follow-up. It shows a good indication for a femoral varus osteotomy in LCPD and probably is a good influence of a “preventive” apophysiodesis, as I presumed above.

FIGURE 1

FIGURE 1

FIGURE 2

FIGURE 2

FIGURE 3

FIGURE 3

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REFERENCES

1. Axer A. Subtrochanteric osteotomy in the treatment of Perthes' disease J Bone Joint Surg Br.. 1965;47:489–499
2. Axer A, Gershuni DH, Hendel D, et al. Indications for femoral osteotomy in Legg-Calvé-Perthes disease Clin Orthop.. 1980;150:78–87
3. Joseph B, Nair NS, Rao KL, et al. Optimal timing for containment surgery for Perthes disease J Pediatr Orthop.. 2003;23:601–606
4. Herring JA, Kim HT, Browne R. Legg-Calve-Perthes disease. Part II: prospective multicenter study of the effect of treatment on outcome J Bone Joint Surg Am. 2004;86-A:2121–2134
5. Joseph B, Rao N, Mulpuri K, et al. How does a femoral varus osteotomy alter the natural evolution of Perthes' disease? J Pediatr Orthop B. 2005;14:10–15
6. Wiig O, Terjesen T, Svenningsen S, et al. The epidemiology and aetiology of Perthes' disease in Norway. A nationwide study of 425 patients J Bone Joint Surg Br.. 2006;88:1217–1223
7. Beer Y, Smorgick Y, Oron A, et al. Long-term results of proximal femoral osteotomy in Legg-Calvé-Perthes disease J Pediatr Orthop. 2008;28:810–824
8. Mirovsky Y, Axer A, Hendel D. Residual shortening after osteotomy for Perthes' disease. A comparative study J Bone Joint Surg Br.. 1984;66:184–188
Keywords:

Perthes; Legg-Calve-Perthes disease; femoral varus osteotomy; Axer

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