Impaction grafting: doing it right

Age-dependent fracture risk in hip revisions with radial impaction grafting technique: a 5-10 year medium-term follow-up study

Radial impaction grafting (RIG) potentially improves the durability and reliability of cementing the femoral components in revision total hip arthroplasty (THA). In this multicenter, prospective study, 88 revision THAs (87 patients) with RIG technique were performed. The average follow-up time was 7.0 years (range, 5.0-10.2). There were 14 femur fractures: 2 intraoperative, 5 within 3 months after surgery, and 7 later in the postoperative stage (range, 5-84 months). Sixteen patients were lost to follow-up and 20 died without stem re-revision. None of the patients have been re-revised for any reason during follow-up. Age was observed to be a significant factor for determining fracture risk. In conclusion, RIG can be considered a reliable surgical technique, especially for younger patients.

Impaction bone grafting in revision hip surgery: past, present and future

Joint replacement surgery can have excellent clinical results. However, as the number of patients undergoing surgery increases, the number of failed joint replacements is set to rise. One of the greatest challenges for the revision surgeon is the restoration of bone stock. This article focuses upon revision hip surgery, with particular reference to the scope of the problem; historical and current solutions to bone loss in the femur and acetabulum; the clinical results following revision surgery; and the basic science behind impaction bone grafting, before ending with possible future directions for improving the restoration of bone stock.

Type III acetabular defect revision with bilobed components: five-year results

Combined segmental and cavitary deficiencies of the acetabulum (American Academy of Orthopaedic Surgeons Type III) are a difficult problem that revision arthroplasty surgeons must tackle with increasing frequency. Porous-coated bilobed acetabular components are a reconstruction option that allows for increased host bone-prosthesis contact with restoration of the anatomic hip center without the use of a structural bone graft. Eleven consecutive Type III acetabular defects in 11 patients were revised with a porous-coated bilobed cup without a structural bone graft between January 1999 and January 2001 and prospectively followed. Average Harris hip scores improved from 36 preoperatively to 85 postoperatively. Radiographic analysis showed improvement in the average vertical displacement of the hip center. Average leg length discrepancies decreased from 34 mm preoperatively to 7 mm postoperatively. There have been no revisions performed or planned. Porous-coated bilobed acetabular components can provide good clinical and radiographic results at intermediate followup for treatment of Type III acetabular deficiencies. Bilobed components offer a viable option for reconstruction of Type III defects without the use of a structural bone graft or cement while maximizing the host bone-implant contact and restoring the native hip center.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

In-vitro study of medial strain distribution in the femur during impaction grafting

Impaction bone grafting (IBG) is widely used for revision hip surgery to compensate for bone stock loss. It is performed by impacting morsellized allograft into the femoral canal and acetabulum prior to cementing new total hip components. Per- and post-operative femoral fractures and post-operative implant subsidence are major complications in IBG. The aim of this study was to investigate the strain distribution on the medial side of the femur during impaction grafting and the subsequent stability of the stem under uniaxial cyclic loading. The Exeter IBG technique was used in conjunction with Howmedica X-change instrumentation. Sawbones® composite femora were used. An impactometer, which provides a known impaction energy and momentum, was used to standardize the impaction process. Three drop heights, 130, 260, and 390 mm, were used for proximal impaction. In-vitro medial hoop strains and the number of impacts were recorded. A drop height of 260 mm was found to provide sufficient energy for impaction without introducing excessive strains to achieve implant stability. Furthermore, a feasibility study was performed on the use of a proximal impaction cap (PIC) to restrain extrusion of the graft during impaction. Although no significant difference in impaction strains or stem stability in uniaxial cylic loading was found by using a PIC, it is postulated that the design of a proximal impactor could be improved to assist with proximal stem alignment and graft containment.

The use of bilobed porous-coated acetabular components without structural bone graft for type III acetabular defects in revision total hip arthroplasty: a prospective study with a minimum 2-year follow-up

A prospective analysis was undertaken of 11 hips (in 11 patients) that underwent revision acetabuloplasties with bilobed, porous-coated, acetabular implants without the use of structural bone graft for type III acetabular defects. The average patient age was 66.3 years, with an average follow-up of 38 months (range, 24-49 months). No acetabular components required or are pending revision surgery. Average pain and hip scores improved from 8 and 36 preoperatively to 42 and 89 postoperatively, respectively. Average leg-length differences decreased from 34 mm preoperatively to 7 mm postoperatively. The use of bilobed acetabular components without structural bone graft is a feasible alternative for reconstructing type III acetabular defects, and can provide good short-term clinical results, while reconstructing the hip center and maximizing host-implant contact.