We prospectively followed 14 patients (15 hips) with severe proximal femoral bone defects reconstructed with a circumferential metal mesh, impacted bone allografts, and a cemented stem between March 2000 and December 2006. During this same period, we revised 356 patients with bone defects using impacted bone allografts and a cemented stem. The right hip was affected in 12 cases and the left hip in three cases in the study group. Initial diagnosis was osteoarthritis in nine cases, developmental dysplasia of the hip in five cases, and rheumatoid arthritis in one case. The indications for revision surgery were septic failures in five cases, aseptic loosenings in three, and Vancouver type B3 [10
] periprosthetic fractures in seven cases (two of these fractures were infected) (Fig. A–B). Two of these 15 cases had been previously operated in our institution. The patients presented an average of 2.2 previous hip surgeries (range, 1–4 surgeries). None of the patients died or were lost to followup. We (MB) collected data prospectively. We used our information sheet in which individual data are collected for every patient. Patients’ average age was 67 years (range, 43–82 years); there was one male and 14 females. The average preoperative Merle D’Aubigné and Postel score [8
] was 4.8 points. The minimum followup was 20 months (average, 43.2 months; range, 20–72 months). We had prior approval of our local ethics review board.
Fig. 1A–B Case 12. (A) Anteroposterior right hip radiograph of a septic failed Vancouver B3 (Duncan) periprosthetic fracture is shown. (B) Anteroposterior right hip radiograph after removal of components and implantation of a long antibiotic-loaded cement spacer (more ...)
We classified femoral deficiencies radiographically before surgery and confirmed the class after removal of components during the procedure using the system reported by Della Valle and Paprosky [9
] and the Endoklinik (Engelbrecht and Heinert) classification [12
] (Table ). There were 14 cases presenting a Type IV and one case with a Type IIIB defect using the system of Della Valle and Paprosky. In a type III femoral defect, the metaphysis is damaged severely and nonsupportive. There is some intact cortical bone present distal to the isthmus. In a type IV defect, there is extensive metadiaphyseal damage in conjunction with a widened femoral canal, the isthmus is nonsupportive, and distal fixation cannot be achieved [9
]. All the cases presented a Grade 4 Endoklinik deficiency, characterized by gross destruction of the proximal third of the femur with involvement of the middle third, precluding the insertion of even stemmed prosthesis [12
]. The average height of the circumferential proximal femoral bone loss was 12 cm (range, 9–15 cm).
Five patients presented having had three previous transtrochanteric approaches, and one patient four previous transtrochanteric approaches. In four patients, severe major trochanteric osteolysis was present and in five the major trochanter was absent due to failed surgeries.
Surgeries were performed by the three authors (MB, FC, FP) following the general principles that have been described for the original impaction grafting technique [15
]. Under epidural hypotensive anesthesia, a posterolateral approach was performed in 13 cases with an additional intrapelvic approach to remove an excessively protruded cup in one case and a transtrochanteric approach in two cases. The presence of active infection during one-stage surgeries or second-stage reimplantations was ruled out in all patients using intraoperative frozen section biopsy [33
] and bacteriologic and pathologic analysis. All implants, polymethylmethacrylate, granulation tissue, and interface were completely removed and the remaining distal femur was identified. The removed failed femoral stems presented an average length of 14.4 cm (range, 12–26 cm) and they were all cemented except one uncemented implant.
The femoral metal mesh was 0.15 inches thick and had 2-mm2 perforations. Fico® (Fico®, Buenos Aires, Argentina) metal mesh was implanted in 13 cases, and X-Change metal mesh (Stryker Howmedica, Newbury, UK) was used in two cases. To make reconstruction easier and to measure the length of the needed mesh, a proximal impactor is temporarily inserted as a form around which the meshes are bent. The meshes were fixed with three double cerclage metal circumferential monofilament wires (Ortron 90; diameter, 1 mm; DePuy Int., Leeds, UK, Warsaw, Ind.) (Fig. A). Approximately 10 cm of circumferential metal mesh was fixed to the remaining bone.
Fig. 2A–C Case 12. (A) This intraoperative photograph shows a distally fixed metal mesh wrapping the remaining femur. (B) Intraoperative aspect of the reconstructed femoral canal is observed prior to cementation. (C) This intraoperative photograph depicts the definitive (more ...)
We obtained bone allografts from frozen femoral heads from our own bank following the protocol of the American Association of Tissue Banks for the harvesting and processing of grafts [13
]. We made the cancellous chips 7 to 10 mm with a grinder from the unwashed bone allografts and mixed for 15 minutes with 1 g dry powdered vancomycin (Lilly, Indianapolis, Ind.) per femoral head according to previous investigations [5
]. Grafts were impacted according to the technique described by Gie et al. [15
] using specific instruments (Primary Impaction Grafting Instruments; DePuy Int., Leeds, UK in 13 cases and Exchange Revision Instruments System; Stryker Howmedica Osteonics, Allendale, NJ in two cases). An additional three double cerclage wires were placed in the proximal mesh to contain the impaction force that was applied uniformly until rotational stability of the impactor was achieved. An average of 3.5 allograft femoral heads were needed per revision, including the acetabulum (range, 3–5). A cancellous bone thickness of 10 mm was intended to be obtained in the proximal part of the reconstructed femur (Fig. B).
We retrogradely injected bone cement CMW1 with gentamicin (DePuy, Warsaw, IN) in 13 cases and Simplex with tobramycin cement (Stryker Howmedica Osteonics, Rutherford, NJ) in two. A C-Stem (DePuy) (Ra 0.05 um) triple-taper polished femoral stem was implanted in 10 cases (Fig. ), a Charnley stem (DePuy) (Ra 0.64 um) was cemented in three cases, and an Exeter stem (Stryker Howmedica Osteonics) (Ra 0.05 um) was used in two cases. The average length of the femoral stems was 222 mm (range, 130–260 mm). A 28-mm femoral head was implanted in 12 cases and a 22.225-mm in three cases. The femoral stems bypassed the circumferential mesh for an average of 5 cm (range, 1–9). The average operative time was 196 minutes (range, 150–240 minutes) (Fig. ).
Case 12. Anteroposterior radiograph of the right hip and proximal femur is observed at 5 years postoperatively.
In aseptic cases we prescribed antibiotic prophylaxis with cefazolin 1 g every 8 hours for 48 hours. All patients with a previous infection received the same intravenous antibiotic treatment that had been used after the first stage; antibiotics were stopped when the infection was controlled. Routine prophylaxis for thromboembolic disease was continued for the first postoperative month. This consisted of intravenous heparin during surgery, early postoperative mobilization, enoxaparin 0.4 mg in patients with a high clinical risk of thromboembolic disease (i.e., malignancy, particularly if associated with chemotherapy; antiphospholipid syndrome, immobility, or a history of venous thromboembolism; administration of tamoxifen, raloxifene, oral contraceptives, or estrogen; morbid obesity; stroke; atherosclerosis; and an American Society of Anesthesiologists physical status classification of 3 or greater), and aspirin 325 mg in patients with a low clinical risk [38
]. We did not routinely prescribe prophylaxis against heterotopic calcification. The mean inhospital transfusion requirements were 3.5 concentrated red blood cell units per case (range, 2–6).
The rehabilitation protocol included early mobilization 48 hours after surgery and ambulation with a walker and toe-touch weightbearing on the operated side for 90 days. After that, we encouraged patients to progressively weight bear as tolerated with the use of a cane for at least 1 month.
Two of us (MB, FC) evaluated patients clinically and radiographically at 15, 45, 90, and 180 days postoperatively and then yearly. We used the Merle D’Aubigné and Postel scoring system [8
]. As a result of the presence of metal meshes and cerclage wires, we could not evaluate the incorporation of the graft. Femoral radiolucencies and periprosthetic osteolysis, defined as progressive bone loss in an area larger than 5 mm2
were assessed in the distal part of the femoral stems, where metal mesh was not present. Femoral radiographic loosening of the Charnley stems was classified according to Harris and McGann in three categories: definitive, probable, and possible loosening [21
]. Subsidence of the femoral stem was determined using the method described by Loudon and Charnley [26
], which depends on measuring the distance from a selected (but variable) point in the femoral prosthesis to a fixed point in the bone.
One patient having repeat surgery agreed to have biopsy specimens from six of the seven zones described by Gruen et al. [17
] through the fenestrations of the metal mesh using a 4-mm Jamshidi needle. These samples were evaluated by an independent orthopaedic pathologist.
We defined clinical failure as the need for further femoral revision irrespective of the reason. The radiographic definition of failure of the polished tapered stems was progressive migration by more than 5 mm in any direction on standard anteroposterior (AP) and lateral radiographs or mesh fracture. Success was defined as the presence of a functional hip prosthesis at the time of the latest followup. A functional hip was considered when pain was absent or slight during walking (with or without the use of a cane) without radiographic findings that indicated the possibility of a future operative intervention.
We determined survival using the Kaplan-Meier survival method using further femoral revision as the end point [22