Can Adding BMP2 Improve Outcomes in Patients Undergoing the SUPERhip Procedure?

Dror Paley,Monica Nogueira,Claire E Shannon,Matthew Harris,Catharina Chiari

doi:10.3390/children8060495

Abstract

Congenital femoral deficiency (CFD) Paley type 1b is characterized by severe bony deformity of the upper femur, extra-articular contractures of the hip, and, delayed ossification of the femoral neck and/or subtrochanteric region. The Systematic Utilitarian Procedure for Extremity Reconstruction of the hip (SUPERhip) procedure for the correction of CFD deformities was developed in 1997. Initially, a non-fixed angle device (rush rod) was used for fixation. Late complications of persistent delayed ossification and recurrent varus deformity occurred. In order to reduce and treat such complications, fixation with a fixed angle device and the off-label use of BMP2 to induce ossification of the un-ossified femoral neck were employed. The purpose of this study is to determine if the use of a fixed angle device, and, BMP2 inserted into a drill hole in the cartilage of the femoral neck, decreases the incidence of these late complications. We retrospectively reviewed 72 SUPERhip procedures performed for Paley type 1b CFD between 1997 and 2012. Due to recurrent varus or persistent delayed ossification of the femoral neck, 34 revision SUPERhip procedures were performed. In total, 106 SUPERhip procedures were studied. Sixty-eight SUPERhips were performed using internal fixation without BMP2, while 38 SUPERhips were performed with both internal fixation and the addition of BMP2. Forty-one were performed using non-fixed angle internal fixation while 65 had fixed angle internal fixation. Fixed angle devices significantly reduced the incidence of recurrent varus compared with non-fixed angle devices. Inserting BMP2 in the femoral neck significantly reduced the incidence of persistent delayed ossification. Using only a fixed angle device but no BMP2 did not reduce the incidence of delayed ossification. The combination of both a fixed angle device and BMP2 reduced the incidence of recurrent coxa vara and persistent delayed ossification of the femoral neck. The SUPERhip procedure corrects the pathoanatomy of the proximal femur in CFD Paley type 1b but is associated with a very high risk of recurrence of coxa vara and persistence of femoral neck delayed ossification, unless, a fixed angle internal fixation device is used to prevent recurrent coxa vara and BMP2 is used to induce ossification of the femoral neck.

Highlights

Congenital femoral deficiency (CFD) is a spectrum of deformity, deficiency, and discrepancy of the femur, hip, and pelvis [1]
0.405 ( BMP- no BMP, Fixed < - fixed angle, +BMP – plus BMP). This finding that Bone morphogenic protein 2 (BMP2) insertion into the femoral neck leads to reduction in delayed This finding that BMP2 inserotsisoinficianttioonthisecfoenmsiosrteanl tnwecitkhltehaedfsintodirnegdsuincttihoenpinrimdealrayySeHd group
The senior author switched to using a fixed angle device, hoping this would prevent the recurrent varus from giving the femoral neck a chance to ossify under load

Summary

Introduction

Congenital femoral deficiency (CFD) is a spectrum of deformity, deficiency, and discrepancy of the femur, hip, and pelvis [1]. In the original version of the SH, the proximal femur osteotomy was fixed with a rush rod and tension band wire construct (Figure 3) [7,8] Late complications, such as recurrent varus deformity and delayed ossification of the femoral neck, were reported in the earliest versions of the SH surgery [7,8]. In order to address the recurrent varus, the non-fixed angle fixation (Rush rod and tension band wire) was replaced with a much stronger fixed angle construct; a sliding hip screw (SHS) (Smith and Nephew, Memphis, TN, USA) or a 130 degree cannulated blade plate (Smith and Nephew, Memphis, TN, USA) [7,8] (Figure 4). All but one case of varus had persistent delayed ossification

Recurrent varus

FOR PEER REVIEW

Findings

Conclusions