Viability of impacted bone allografts under metal mesh at the calcar in revision surgery of the hip

Comparative Study on the Application of Mesenchymal Stromal Cells Combined with Tricalcium Phosphate Scaffold into Femoral Bone Defects

This prospective study sought to evaluate the healing quality of implanted ultraporous β-tricalcium phosphate sown with expanded autologous mesenchymal stromal cells (MSCs) into femoral defects during revision hip arthroplasty. A total of 37 osseous defects in 37 patients were treated and evaluated concerning bone regeneration. Nineteen subjects received β-tricalcium phosphate graft material serving as a carrier of expanded autologous MSCs (the trial group A), nine subjects received β-tricalcium phosphate graft material only (the study group B) and nine subjects received cancellous allografts only (the control group C). Clinical and radiographic evaluations were scheduled at 6 weeks, 3, 6, and 12 months post-operatively, and performed at the most recent visit as well. All observed complications were recorded during follow-up to assess the use of an ultraporous β-tricalcium phosphate synthetic graft material combined with expanded MSCs in bone defect repair. The resulting data from participants with accomplished follow-up were processed and statistically evaluated with a Freeman–Halton modification of the Fischer’s exact test, a P < 0.05 value was considered to be significant. Whereas no significant difference was observed between the trial group A with β-tricalcium phosphate synthetic graft material serving as a carrier of expanded autologous MSCs and control group C with cancellous impaction allografting in terms of the bone defect healing, significant differences were documented between the study group B with β-tricalcium phosphate graft material only and control group C. Regarding adverse effects, six serious events were recorded during the clinical trial with no causal relationship to the cell product. β-tricalcium phosphate synthetic graft material serving as a carrier of expanded autologous MSCs appears safe and promotes the healing of bone defects in a jeopardized and/or impaired microenvironment. This clinical trial was registered at the EU Clinical Trials Register before patient recruitment (Registration number: EudraCT number 2012-005599-33; Date of registration: 2013-02-04).

Treatment of large acetabular defects: a surgical technique utilizing impaction grafting into a metallic mesh

BACKGROUND

Revision total hip arthroplasty in cases with severe acetabular bone loss is challenging. In the presence of combined cavitary and segmental defects without superior acetabular coverage, reconstructions with a structural acetabular allograft protected by a cage or a custom-made triflange cage have been the treatment of choice. The current paper describes an impaction grafting into a mesh for uncontained defects in revision total hip arthroplasty.

DESCRIPTION OF TECHNIQUE

After restoring containment with a mesh fixed with small fragment screws, defects were restored using impaction grafting combined with a cemented all-polyethylene cup.

PATIENTS AND METHODS

Fourteen consecutive acetabular impaction graftings were performed by two surgeons. All patients had a type 3B defect according to the Paprosky classification.

RESULTS

No re-revisions or radiographic failure was detected in the early follow-up period.

CONCLUSION

Impaction grafting into a mesh is an interesting treatment option to restore bone in combined cavitary and segmental defects.

The extent of the bone defect affects the outcome of femoral reconstruction in revision surgery with impacted bone grafting: a five- to 17-year follow-up study

We report the results of 79 patients (81 hips) who underwent impaction grafting at revision hip replacement using the Exeter femoral stem. Their mean age was 64 years (31 to 83). According to the Endoklinik classification, 20 hips had a type 2 bone defect, 40 had type 3, and 21 had type 4. The mean follow-up for unrevised stems was 10.4 years (5 to 17). There were 12 re-operations due to intra- and post-operative fractures, infection (one hip) and aseptic loosening (one hip). All re-operations affected type 3 (6 hips) and 4 (6 hips) bone defects. The survival rate for re-operation for any cause was 100% for type 2, 81.2% (95% confidence interval (CI) 67.1 to 95.3) for type 3, and 70.8% (95% CI 51.1 to 90.5) for type 4 defects at 14 years. The survival rate with further revision for aseptic loosening as the end point was 98.6% (95% CI 95.8 to 100). The final clinical score was higher for patients with type 2 bone defects than type 4 regarding pain, function and range of movement. Limp was most frequent in the type 4 group (p < 0.001). The mean subsidence of the stem was 2.3 mm (SD 3.7) for hips with a type 2 defect, 4.3 mm (SD 7.2) for type 3 and 9.6 mm (SD 10.8) for type 4 (p = 0.022). The impacted bone grafting technique has good clinical results in femoral revision. However, major bone defects affect clinical outcome and also result in more operative complications.

Impacted bone allografts and a cemented stem after failure of an uncemented stem: preliminary results

We reviewed the results of impaction bone grafting technique and a cemented stem in 27 consecutive patients with a failed uncemented femoral component. At an average follow-up of 55 months (25 to 94) none of the femoral components were removed or revised because of aseptic loosening or deep infection. In one hip a non progressive radiolucent line was observed in Gruen zone 5 with no clinical evidence of failure. The average postoperative Merle d'Aubigné and Postel Hip Score was 5.8 points for pain, 5.5 points for mobility and 5.4 points for gait. Revision of a failed uncemented stem with impaction grafting technique provided pain relief and improved function. The rate of success and restoration of bone stock were encouraging at mid-term follow-up.

Proximal femoral reconstructions with bone impaction grafting and metal mesh

Extensive circumferential proximal cortical bone loss is considered by some a contraindication for impaction bone grafting in the femur. We asked whether reconstruction with a circumferential metal mesh, impacted bone allografts, and a cemented stem would lead to acceptable survival in these patients. We retrospectively reviewed 14 patients (15 hips) with severe proximal femoral bone defects (average, 12 cm long; 14 type IV and one type IIIB using the classification of Della Valle and Paprosky) reconstructed with this method. The minimum followup was 20 months (average, 43.2 months; range, 20-72 months). Preoperative Merle D'Aubigné and Postel score averaged 4.8 points. With revision of the stem as the end point, the survivorship of the implant was 100% at one year and 86.6% at 72 months. The mean functional score at last followup was 14.4 points. We observed two fractures of the metal mesh at 31 and 48 months in cases reconstructed with a stem that did not bypass the mesh. Dislocation (3 cases) and acute deep infection (3 cases) were the most frequent complications. Patients with complete absence of the proximal femur may be candidates for biological proximal femoral reconstructions using this salvage procedure. Bone impaction grafting must be a routine technique if this method is selected.

The Long Oblique Revision component in revision arthroplasty of the hip

Migration of the acetabular component may give rise to oval-shaped bone defects in the acetabulum. The oblong implant is designed to fill these defects and achieve a stable cementless anchorage with no significant bone loss. We prospectively reviewed 133 oblong long oblique revision components at a mean follow-up of 9.74 years (0.6 to 14). All had been used in revisions for defects of type IIB to IIIB according to Paprosky. Aseptic loosening was the reason for revision in 11 cases (8.3%) and deep infection in seven (5.3%). The probability of implant survival over a 12-year follow-up estimated by the Kaplan-Meier method gave a survival rate of 0.85% respectively 0.90% when deep infection was excluded as the endpoint.

Our study supports the use of these components in defects from IIB to IIIA. The main precondition for success is direct contact of more than half of the surface of the implant with the host acetabular bone.

Acetabular revision with metal mesh, impaction bone grafting, and a cemented cup

Impaction grafting is controversial in the presence of segmental and cavitary acetabular defects and requires the use of supplemental devices to close segmental defects. This approach, however, would allow treating combined deficiencies that could not be managed with impacted cancellous bone alone. We raised the following two questions: (1) What is the survival rate in patients with combined deficiencies reconstructed with metal mesh, impaction grafting and a cemented cup and (2) can metal mesh prevent cup migration? We evaluated 23 cavitary uncontained acetabular defects in revision hip arthroplasty. Preoperative diagnoses were aseptic loosening (19 hips) and second-stage reimplantations after resection for infection (four hips). The preoperative Merle D'Aubigné-Postel score averaged 7.4 points. Two patients had reoperations for mechanical failure at 6 and 24 months. The survival rate with further revision as an end point was 90.8% at an average of 36 months (range, 24-56 months; 95% confidence interval, 68.1-97.6). Metal mesh did not prevent cup migration: migration occurred in all patients, averaging 5.1 mm (range, 2-25 mm). Another three patients with severe combined defects had asymptomatic mesh rupture with 3- to 15-mm migration. Postoperative functional score averaged 16.2 points. Metal mesh, impaction grafting, and a cemented cup should be considered for reconstruction of medium uncontained acetabular defects, but not for severe combined deficiencies.

LEVEL OF EVIDENCE

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