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Varus Derotational Osteotomy.

The current accepted treatment options for Legg-Calve-Perthes disease are based on the concept of containment. Containment can be achieved by positioning the extruding femoral head in a more covered position. This increase in coverage has been theorized to offset the disease progression and provide a more favorable remodeling potential. The varus derotational osteotomy (VDRO) is one such treatment modality and has been widely accepted as a current mainstay of treatment for hip containment in Legg-Calve-Perthes disease.

History

In 1929 Parker described the use of plaster abductions casts to position the entire epiphysis within the acetabulum. (1) The Parker "broomstick abduction cast" was one of the earliest known treatment options for Perthes disease. Later, many braces were created that mimicked the function of the original abduction casts. However, despite more wide adoption of abduction braces, patients would remain awkwardly constrained by the devices, negatively affecting patient compliance and adherence. It was not until 1965 when Axer described the first femoral osteotomy for the treatment of Perthes disease. His goal was to find "a less restricted method of treatment yielding similar or better results." The procedure was described as a varus subtrochanteric osteotomy with rotation, positioning the "plastic" epiphysis in the center of the joint space. (2) In his series of 12 patients from 1957 to 1963, 11 were noted to have "very good to good" outcomes with a mean remodeling time of 15.5 months. Only one patient was noted to have limitation of movement with a limp and a limb length discrepancy of 2.5 cm. All patients were immobilized for an average of 2 to 3 months in a plaster spica cast until radiographic signs of union. In 1976, Lloyd Roberts and Catterall3 performed the first randomized control study looking at untreated Perthes disease (total of 75 patients) in comparison to 48 patients treated with varus rotational osteotomy. They showed that the patients that had the best results after osteotomy were those in whom the operation was performed within 7 months of symptoms. They also found that patients treated at around the age of 6 years had better results compared to those treated at a much older age. (3) These early pioneering studies paved the way for further developments regarding operative management of Perthes disease.

Biology

Axer and Schiller (4) suggested that one of the effects of varus osteotomy was interruption of the destructive phase of Perthes disease and a reduction in the duration of the disease. Joseph et al. (5) further corroborated Axer's findings, demonstrating that in fact some children operated at stage I of the disease had an overall reduction in the duration of the disease primarily because of the bypass of the stage of fragmentation. Even in children who did pass through the stage of fragmentation, the duration of the fragmentation phase was shorter than in children treated non-operatively. Additionally metaphyseal widening and epiphyseal extrusion, both of which tend to increase abruptly in non-operated children, are minimized in patients who underwent femoral osteotomy. (5) Heikkinen and Puranen (6) theorized that beside providing containment, the varus rotational osteotomy had a beneficial effect on the "disturbed venous drainage" of the affected hip in addition to decreasing the load against the involved head without restricting normal activity. They looked at 67 patients treated with the osteotomy and found that 74% of patients between the age of 5 to 9 years had good results as opposed to only 40% of patients older than 9 years of age. They also performed venography on selected patients showing venous pooling and congestion in the affected hips was relieved by osteotomy improving femoral head blood flow. (6) However in 1992, Lee et al. (7) performed serial quantitative scintigraphic studies on 25 hips with Perthes disease pre- and post-VDRO. The studies were performed preoperatively and at 2 weeks, 6 weeks, 6 months, 1 year, and 2 years postoperatively. These investigators found that the vascularity of the femoral head decreased significantly at the 2-week initial visit, however thereafter it steadily increased back to its preoperative level by 6 months with no statistically significant increase from the preoperative level at 2 years. (7)

Techniques

Since Axer's original publication in 1965, the varus osteotomy has been adopted by surgeons and further modified to allow for better surgical outcomes. Axer in 1980 published an update to his original paper. He described three variations that included excision of a medial based wedge with its reversal to obtain "varusation and containment" with anterior head containment by derotation. In the cases in which he was unable to achieve the desired degree of medial rotation of the proximal fragment, an excision of a posterior based wedge to obtain head containment by extension was performed. In young children (less than 6 years of age) an opening wedge technique was performed with a transverse division of the shaft in the subtrochanteric region, followed by pre-bending of the plate to the appropriate varus angle and application. He also decreased the postoperative immobilization and spica casting to only a total of 6 weeks. (8) Grant and Lehman (9) described an innovative technique utilizing a cannulated blade plate for varus osteotomy. The system included cannulated chisels and a cannulated one piece plate that could be inserted over a guidewire. They also recommended using a pre-templated and predetermined line known as the neck metaphyseal angle for determination of the position of the wire and blade placement to allow a reliable correction of the neck shaft angle. (9,10) Joseph et al. (11) described using a combination of a trochanteric epiphyseodesis and varus osteotomy. No plaster immobilization, but weightbearing was avoided until mature bone was seen to cover the lateral part of the femoral epiphysis. In this study, they found a much larger proportion of children who had this operation had spherical femoral heads compared to a control group (62.5% vs. 20%, p < 0.001). They performed the procedure on Catterall groups II to IV, children ages 7 to 12 years. (11) Ito et al. (12) described using a three-dimensional corrective external fixator system for the varus and rotational correction. In their series, 36 patients with Perthes disease were treated with the technique for 3 months. All achieved union at a mean of 4 months from the original surgery. No avascular necrosis, malunions, or device failures were noted. (12) Atsumi and Yoshiwara (13) described a rotational open wedge osteotomy for patients older than 7 years of age with Perthes disease. In their technique, a cannulated blade plate was used and partially inserted in an anteriorly shifted position. Next an intertrochanteric osteotomy was performed. After osteotomy, the plate was further "seeded" to the appropriate depth. The device was then rotated posteriorly and fixed in line with the femoral shaft. Using this technique on 19 patients with Perthes disease Catterall stage III and IV, they noted an accelerated rate of repair of the fragmented epiphysis by 12 months. The mean age of the patient population was 7.8 years. (13) Kim et al. (14) assessed 52 patients treated with proximal femoral varus osteotomies for Perthes disease in a multicenter prospective study. All patients were 6 years or older at the time of diagnosis (mean age: 8 years). They found that greater varus angulation did not produce better preservation of the femoral head. Based on their findings, over or under "varusization" did not provide the most favorable outcomes. The best outcomes were noted in patients with initial lateral pillar B classification with only 10[degrees] to 15[degrees] of varus correction. (14)

Time of Intervention

Although many have accepted the benefit of varus derotational osteotomy for the treatment of Perthes disease, much controversy remains on the appropriate time and stage for maximal benefit from treatment. In 1980, Laurent and Poussa (15) looked at 78 patients in Catterral group II, III, and IV who underwent subtrochanteric varus derotational osteotomy as proposed by Axer. The average age of patients with the onset of symptoms was 6 years and 6 months. The average age at the time of osteotomy was 7 years and 8 months. They found that patients who had the osteotomy within 1 year of onset of symptoms and were Catterall stage II and III at intervention had the best outcomes. (15) Friedlander and Weiner (16) conducted a retrospective review of 116 patients with varus osteotomy for Herring group B and C disease. Radiographic outcome was assessed utilizing Stulberg's classification to grade residual deformity. The average follow-up time was 6 years and 9 months. Stulberg class I and II (spherically congruent) were obtained in 86% of patients younger than 9 years old with Herring class B disease. Patients 9 years and older with Herring class B disease had spherically congruent results in 67% of cases. Patients with Herring class C disease 9 years and older had spherically congruent results in only 30% of cases. Only 43% of patients who were 9 years or younger with Herring class C disease at time of intervention had congruent results. (16) Joseph et al. (5) evaluated the optimal timing for containment surgery for Perthes disease. Ninety-seven patients who underwent the femoral osteotomy technique as described by these investigators were included in the study. The mean age of patient population was 8 years. Using univariate and multivariate analysis, the most significant variable that had a bearing on outcome was timing of surgery. The chances of retaining a spherical femoral head were much higher in children operated on either at the stage of avascular necrosis or in the early part of the fragmentation stage than in those operated later. The goal of surgical intervention was effectively to bypass the stage of fragmentation by containment of the femoral head. Through early intervention, the integrity of the lateral pillar was maintained, the duration of the disease was reduced compared to prior controls, and the adverse metaphyseal and acetabular changes that tend to appear most frequently in the stage of fragmentation did not develop. (5)

Complications

As with any surgical intervention, varus derotational osteotomies are associated with potential complications. The complications described in the literature include premature epiphyseal closure, leg length discrepancy, greater trochanter overgrowth, abductor lurch, loss of motion, pain, and over varusization.

Premature epiphyseal closure after VDRO was described by Barnes (17) in 1980. He reviewed 22 patients with an average age of onset of 6 years who had Catterall group III and IV disease and who developed premature closure compared to the contralateral hip. The patients had a follow-up at an average age of 14 years and had an average leg length discrepancy range of 0.5 to 3.0 cm (average: 2 cm). Another complication noted in the study was greater trochanter overgrowth in some patients. Decrease in abduction did correlate with greater trochanter overgrowth (impingement on the ilium), however the Trendelenburg sign, which was seen in 7 patients, did not correlate. Overall, 16 patients were pain free and active, while 6 had occasional pain after activity. (17) Leitch (18) looked at 72 patients with Perthes disease, 20 of whom were treated with VDRO, and 27 of whom were treated with a Salter (innominate) osteotomy. The Catterall grade at time of diagnosis was evenly spread across all groups (Grades II through IV). The study showed a leg length discrepancy of greater than 2 cm in a total of 6% of patients in the total population (13% of patients treated with VDRO and 9% of patients treated non-operatively). Greater trochanter overgrowth (determined by articulotrochanteric distance less than 5 mm on final AP pelvis radiograph) was noted in 26% of the patients treated with VDRO, however interestingly, 29% of patients treated non-operatively also had the phenomenon. Forty-three percent of the patients with greater trochanter overgrowth had a positive Trendelenburg sign. Weiner et al. (19) reviewed 79 patients who underwent VDRO. Patients were Catterall II, III, or IV at time of indication for surgery. The average age at surgery was 7.3 years, and average follow-up was 4.8 years. Fifteen patients developed "pitfalls" which included greater trochanter overgrowth (nine patients), persistent varus angulation less than 105[degrees] (seven patients), shortening of the extremity greater than 1 inch (three patients), and premature physeal closure (nine patients). Of the patients that underwent greater trochanteric epiphysiodesis at initial surgery, only two patients (5.4%) developed a complication. In contrast, in the patients operated with osteotomy without epiphysiodesis, 14 patients (28%) developed a complication. Sixteen patients had immediate postoperative varus inclination of less than 105[degrees], and seven of those (44%) developed a complication. Of the 63 patients that had postoperative varus of greater than 105[degrees], only eight (13%) had a complication. So conclusions from this study showed that over varusization of less than 105[degrees] and trochanter epiphysiodesis at initial surgery were less likely to be associated with long-term problems, however no statistical analysis was performed in the study. (19)

Conclusions

The varus derotational osteotomy is an acceptable treatment option for Legg-Calve-Perthes disease. Since its description by Axer in 1965, it has been a mainstay in the treatment algorithm. Since its inception, it has undergone many iterations with a variety of techniques described to achieve the same goal: femoral head containment. By positioning an extruding femoral head in a more covered position, there is a theoretical benefit for accelerated healing, decrease in fragmentation of the epiphysis, and potential change in the vascular supply. Although the risks with this procedure are low, there is a potential for complications that may require adjunct procedures. The varus derotational osteotomy should be considered in the management of Perthes disease and will remain a mainstay in treatment in the future.

Disclosure Statement

None of the authors have a financial or proprietary interest in the subject matter or materials discussed in the manuscript, including, but not limited to, employment, consultancies, stock ownership, honoraria, and paid expert testimony.

References

(1.) Harrison MH, Menon MP. Legg-Calve-Perthes disease. The value of roentgenographic measurement in clinical practice with special reference to the broomstick plaster method. The J Bone Joint Surg Am. 1966 Oct;48(7):1301-18.

(2.) Axer A. Subtrochanteric osteotomy in the treatment of Perthes' disease. J Bone Joint Surg Br. 1965 Aug;47:489-99.

(3.) Lloyd-Roberts GC, Catterall A, Salamon PB. A controlled study of the indications for and the results of femoral osteotomy in Perthes' disease. J Bone Joint Dis Br. 1976 Feb;58(1):31-6.

(4.) Axer A, Schiller MG. The pathogenesis of the early deformity of the capital femoral epiphysis in Legg-Calve-Perthes syndrome (LCPS): An arthrographic study. Clin Orthop Relat Res. 1972 May;84:108-15.

(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 Jan;14(1):10-5.

(6.) Heikkinen E, Puranen J. Evaluation of femoral osteotomy in the treatment of Legg-Calve-Perthes disease. Clin Orthop Relat Res. 1980 Jul-Aug;(150):60-8.

(7.) Lee DY, Seong SC, Choi IH, et al. Changes of blood flow of the femoral head after subtrochanteric osteotomy in Legg-Perthes' disease: a serial scintigraphic study. J Pediatr Orthop. 1992 Nov-Dec;12(6):731-4.

(8.) Axer A, Gershuni DH, Hendel D, Mirovski Y. Indications for femoral osteotomy in Legg-Calve-Perthes disease. Clin Orthop Relat Res. 1980 Jul-Aug;(150):78-87.

(9.) Grant AD, Lehman WB, Strongwater AM, Atar D. Cannulated blade plate for proximal femoral varus osteotomy. Clin Orthop Relat Res. 1990 Oct;(259):111-3.

(10.) Grant AD, Strongwater A, Lehman W, et al. Neck metaphyseal angle guidance in proximal femoral varus osteotomy. J Pediatr Orthop. 1990 Jan-Feb;10(1):9-13.

(11.) Joseph B, Srinivas G, Thomas R. Management of Perthes disease of late onset in southern India. The evaluation of a surgical method. J Bone Joint Surg Br. 1996 Jul;78(4):625-30.

(12.) Ito H, Minami A, Suzuki K, Matsuno T. Three-dimensionally corrective external fixator system for proximal femoral osteotomy. J Pediatr Orthop. 2001 Sep-Oct;21(5):652-6.

(13.) Atsumi T, Yoshiwara S. Rotational open wedge osteotomy in a patient aged older than 7 years with Perthes' disease --a preliminary report. Arch Orthop Trauma Surg. 2002 Jul;122(6):346-9.

(14.) Kim HK, da Cunha AM, Browne R, et al. How much varus is optimal with proximal femoral osteotomy to preserve the femoral head in Legg-Calve-Perthes disease? J Bone Joint Surg Am. 2011 Feb;93(4):341-7.

(15.) Laurent LE, Poussa M. Intertrochanteric varus osteotomy in the treatment of Perthes' disease. Clin Orthop Relat Res. 1980 Jul-Aug;(150):73-7.

(16.) Friedlander JK, Weiner DS. Radiographic results of proximal femoral varus osteotomy in Legg-Calve-Perthes disease. J Pediatr Orthop. 2000 Sep-Oct;20(5):566-71.

(17.) Barnes JM. Premature epiphysial closure in Perthes' disease. J Bone Joint Surg Br. 1980 Nov;62-B(4):432-7.

(18.) Leitch JM, Paterson DC, Foster BK. Growth disturbance in Legg-Calve-Perthes disease and the consequences of surgical treatment. Clin Orthop Relat Res. 1991;(262):178-84.

(19.) Weiner SD, Weiner DS, Riley PM. Pitfalls in treatment of Legg-Calve-Perthes disease using proximal femoral varus osteotomy. J Pediatr Orthop. 1991 Jan-Feb;11(1):20-4.

Surya N. Mundluru, MD, and David Feldman, MD

Surya N. Mundluru, MD, and David Feldman, MD, Department of Orthopedic Surgery, NYU Langone Orthopedic Hospital, NYU Langone Health, New York, New York, USA.

Correspondence: Surya N. Mundluru, MD, Department of Orthopedic Surgery, NYU Langone Orthopedic Hospital, NYU Langone Health, 301 East 17th Street, New York, New York, 10003, USA; smundluru@gmail.com.

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Author:Mundluru, Surya N.; Feldman, David
Publication:Bulletin of the NYU Hospital for Joint Diseases
Article Type:Report
Date:Jan 1, 2019
Words:2897
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