Abstract
Substantial bone loss and bone defects are the most challenging problems faced by the surgeon performing revision surgery. Of the many techniques available, impaction bone grafting aims to achieve stability of an implant with the use of compacted, morselized bone graft and subsequently allows restoration of bone stock by bone ingrowth. This technique was proposed with a highly polished double tapered stem. This technique has also been subsequently used with stems of varying surface finish and shape. We report here our experience with impaction grafting using Charnley stem and variants with 8–10 year results assessing the radiological appearance and subsequent behaviour of the impacted allograft.
A prospective radiological study of revision hip arthroplasty done for aseptic loosening with femoral bone loss is presented. Pre operative bone loss was assessed using the Endo Klinik grading system. Impaction grafting with fresh frozen femoral head allograft and the flanged 40 size Charnley stem was used in 17 cases and extra heavey flanged 40 size was used in 9 casaes. Post operative and annual review radiographs were examined for graft distribution, graft consolidation, cortical repair and subsidence of the stem.
Twenty six revisions performed in 25 patients between May 1994 and November 1996 were followed up for 8–10 years. Mean age was 66 years(range 26–83 years). There were eighteen male and 7 female patients. One patient died 2 years and 9 months after the operation. Pre operatively Endo Klinik grade 2 bone loss was seen in 7 cases and grade 3 bone loss was seen in 19 cases. Post operative radiographs showed even graft distribution in twenty cases, five patients had poor filling in Gruen zone 3 and one patient had poor filling in zone 2. All cases demonstrated evidence of graft consolidation by one year. Twenty two cases showed no further changes after 8–10 years. Two cases of subsidence have been revised and one patient is awaiting revision ( 8 years after revision). Two of these were extra heavy flanged 40 stems. Three cases showed subsidence > 5mm and were associated with graft deficiency in zone 2 or 3. Out of these three one had an extra heavy flanged 40 stem inserted. There were no medical complications or deep infection following surgery in these patients. One patient had dislocation.
In conclusion, femoral revision using impaction grafting with the Charnley stem produces satisfactory radiological results in the medium to long term. Good graft distribution on a postoperative radiograph is associated with graft consolidation, cortical repair and minimal stem subsidence. Extra heavy flanged 40 stems perform less satisfactorily compared to the flanged 40 stems. Inadequate graft filling is associated with stem subsidence and revision. These findings highlight the importance of meticulous surgical technique to ensure even graft distribution. This study supports the taper of the Charnley stem and suggests that a vaquasheen finish is not contraindicated.
Editoral Secretary Mr Peter Howard. Correspondence should be addressed to BHS at the Royal College of Surgeons, 35 - 43 Lincoln’s Inn Fields, London WC2A 3PN.
