Telescoping Allograft Prosthetic Composite (APC) Reconstruction of the Femur Following Revision Arthroplasty for Neglected Developmental Dysplasia of the Hip (DDH)

Abstract

Although uncommon, neglected developmental dysplasia of the hip (DDH) poses a technically demanding problem for treating surgeons. Due to the congenital malformation of the native hip joint and distortion of the surrounding soft tissue, addressing limb-length discrepancy is intricate. Despite detailed planning and meticulous soft tissue handling, complications can be difficult to avoid in these patients even under experienced hands. In this case report, we present a 73-year-old lady with neglected DDH who had undergone initial total hip arthroplasty and subsequent revision surgery that failed due to aseptic loosening. Due to limited length in the distal femur, we used a telescoping allograft prosthetic composite (APC) to provide adequate length to the native distal femur during revision with proximal femur fixation. This technique can help avoid the need for total femur replacement (TFR) surgery, which is more invasive and may require tibia replacement.

Keywords: allograft prosthesis; bone allograft; developmental dysplasia of the hip; hip reconstruction; limb lengthening; limb reconstruction; reconstruction hip and knee surgery.

Figure 1. (A) Plain radiograph of the pelvic prior to the surgery; (B) Plain radiograph of the right hip in lateral view; (C) Plain radiograph of the pelvic after the index right total hip replacement (THR). A cementless stem was inserted, and the superolateral dysplastic pseudoacetabulum was reconstructed with acetabulum cup and augmented with trabecular metal; (D) A femur iatrogenic fracture occured during the index total hip reconstruction (yellow arrow).

Figure 2. (A) Three months after the index right hip surgery, the fracture appeared to be healing with signs of callus formation (yellow arrow); (B) Two years after the surgery, plain radiograph of the right hip showed well-united fracture but also revealed peri-implant radiolucency (green arrows), suggestive of stem loosening; (C) Plain radiograph of the right hip in lateral view after the patient underwent revision surgery where a cemented stem was inserted with a revision/calcar hip system and a shortening osteotomy; (D) Plain radiograph of the right hip in anteroposterior view.

Figure 3. (A) Plain radiograph of the right hip in anteroposterior view revealed loosening of the implant with the tip of the stem spanning 7 cm from the knee joint; (B) Lateral view of the right hip plain radiograph; (C) Plain radiograph in anteroposterior view after revision with allograft prosthesis composite (APC). A size-12 stem was used in this case with a length of 125 mm; (D) Lateral view of the plain radiograph.

Figure 4. (A) The breakdown of the allograft prosthesis composite (APC) construct. Cerclage cable with crimps are being used as the cerclage wires; (B) Plain radiograph of the right femur revealed a well-incorporated APC.