Implant stability in revision total hip arthroplasty: allograft bone packing following extended proximal femoral osteotomy

Extended Trochanteric Osteotomy Closure Performed Before or After Canal Preparation and Stem Impaction Does Not Affect Axial Stability

BACKGROUND

An extended trochanteric osteotomy (ETO) safely addresses femoral component removal during challenging revision total hip arthroplasty. However, no prior study has evaluated whether a difference in axial stability exists between ETO closure performed before (reconstitution) or after (scaffolding) canal preparation and stem impaction. We hypothesized that given the absence of clinical reports of outcome differences despite the wide use of both practices, no significant difference in the initial axial stability would exist between the 2 fixation techniques.

METHODS

ETOs were performed and repaired using the reconstitution technique for the 6 right-sided femora and the scaffolding technique for the six left-sided femora. The 195-mm long, 3.5°-tapered splined titanium monobloc stems were impacted into 6 matched pairs of human fresh cadaveric femora. Three beaded cables were placed in a standardized fashion on each specimen, 1 for prophylaxis against osteotomy propagation during reaming/impaction and 2 to close the ETO. Stepwise axial loading was performed to 2600 N or until failure, which was defined as subsidence >5 mm or femoral/cable fracture.

RESULTS

All specimens successfully resisted axial testing, with no stem in either ETO repair group subsiding >2 mm. The mean subsidence for the reconstitution group was 0.9 ± 0.4 mm, compared to 1.2 ± 0.5 mm for the scaffolding group (P = .2).

CONCLUSION

In this cadaveric model with satisfactory proximal bone stock, no difference existed between the reconstitution and scaffolding ETO repair techniques, and both provide sufficient immediate axial stability in a simulated revision total hip arthroplasty setting under physiologic loads.

Extended trochanteric osteotomy: improving the access and reducing the risk in revision THA

This review article presents a comprehensive literature review regarding extended trochanteric osteotomy (ETO).

The history, rationale, biomechanical considerations as well as indications are discussed.

The outcomes and complications as reported in the literature are presented, discussed and compared with our own practice.

Based on the available evidence, we present our preferred technique for performing ETO, its fixation, as well as post-operative rehabilitation.

The ETO aids implant removal and enhanced access. Reported union rate of ETO is high. The complications related to ETO are much less frequent than in cases when accidental intra-operative femoral fracture occurred that required fixation.

Based on the literature and our own experience we recommend ETO as a useful adjunct in the arsenal of the revision hip specialist.

Cite this article: EFORT Open Rev 2020;5:104-112. DOI: 10.1302/2058-5241.5.190005

The evolution of the technique of impaction bone grafting in femoral revision surgery has improved clinical outcome. A prospective mid-term study

Ninety-three patients (97 hips) underwent impaction bone grafting (IBG) using a cemented tapered femoral stem at our institution. Forty-one hips were operated between 1993 and 1998 (group 1) and 56 hips between 1999 and 2007 (group 2). The use of an extended trochanteric osteotomy and a long stem was more frequent in group 2. Group 2 hips showed a better clinical result. One hip was revised for aseptic loosening and most failures were early periprosthetic fractures. The survival rate for reoperation for any cause was 82.9% for group 1 and 84.3% for group 2. Patients in group 1 had a higher risk for periprosthetic fractures and radiological subsidence >5mm. Experience and the evolution of the IBG technique have improved the good long-term outcome.

An in-vitro biomechanical study of different fixation techniques for the extended trochanteric osteotomy in revision THA

Background

The wire fixation and the cable grip fixation have been developed for the extended trochanteric osteotomy (ETO) in the revision of total hip arthroplasty (THA). Many studies reported the postoperative performance of the patients, but with little quantitative biomechanical comparison of the two fixation systems.

Methods

An in-vitro testing approach was designed to record the loosening between the femoral bed and the greater trochanter after fixations. Ten cadaveric femurs were chosen in this study. Each femur underwent the THA, revision by ETO and fixations. The tension to the greater trochanter was from 0 to 500N in vertical and lateral direction, respectively. The translation and rotation of the greater trochanter with respect to the bony bed were captured by an optical tracking system.

Results

In the vertical tension tests, the overall translation of the greater trochanter was observed 0.4 mm in the cable fixations and 7.0 mm in the wire fixations. In the lateral tension tests, the overall motion of the greater trochanter was 2.0 mm and 1.2° in the cable fixations, while it was 6.2 mm and 5.3° in the wire fixations. The result was significantly different between the two fixation systems.

Conclusions

The stability of the proximal femur after ETO using different fixations in the revision THA was investigated. The cable grip fixation was significantly more stable than the wire fixation.

Extended trochanteric osteotomy followed by cemented impaction allografting in revision hip arthroplasty

The aim of this study is to present the medium- to long-term results of all cases of femoral impaction allografting revision at our institution that required an extended trochanteric osteotomy (ETO) at the time of surgery. Eighteen patients with a mean age of 60 years were evaluated. Indication for revision was aseptic loosening in all cases. The mean follow-up was 123 months (51-170). Charnley-D'Aubigné-Postel scores, stem length, ETO length, ETO healing, and complications were recorded. No patient was lost to follow-up. Signs of clinical healing were noted within the first 6 postoperative months. The difference between the preoperative and postoperative clinical scores was statistically significant. No nonunion of the ETO was observed in any case. These results give support to the combined use of these techniques.

The vertical humeral osteotomy for stem removal in revision shoulder arthroplasty: results and technique

HYPOTHESIS

Revision shoulder arthroplasty represents a complex and difficult problem for the treating surgeon, with multiple potential complications. In the setting of a well-fixed humeral component, removal can lead to fractures and compromise the outcome of the revision. The current study describes and evaluates the results of a novel vertical humeral osteotomy (VHO) for stem extraction. We hypothesized that the VHO will enable successful stem extraction without perioperative or postoperative fractures.

MATERIALS AND METHODS

Twenty-seven patients were retrospectively identified who had a VHO for revision shoulder arthroplasty, with 23 patients available for final follow-up. Records and radiographs were reviewed for postoperative complications. Final follow-up was completed with the inclusion of shoulder scores.

RESULTS

There were no perioperative or postoperative fractures on clinical examination and radiographic review at an average follow-up of 41 months. Average American Shoulder and Elbow Surgeons (ASES) score was 64.7 (contralateral ASES, 76.9), average Simple Shoulder Test was 6.3, and the visual analog score pain average was 1.3. There were no instability events.

DISCUSSION

The glenoid is the more common site for failure in both hemiarthroplasty and total shoulder arthroplasty. This can lead to a difficult revision procedure if the ingrown or cemented humeral stem requires removal.

CONCLUSION

In the current study, we found the VHO was an effective tool for the removal of the humeral prosthesis with no perioperative or postoperative fractures.

Extended femoral osteotomy and proximally coated prosthesis for hip revision

Extended trochanteric osteotomy facilitates femoral reconstruction in revision total hip arthroplasty. This study examined the outcome of extended trochanteric osteotomy combined with a proximally porous-coated calcar replacement prosthesis during revision total hip arthroplasty. Forty-five cases were reviewed with an osteotomy union rate of 98%. No femoral component was loose radiographically, and none were revised for loosening. These findings indicate excellent short-term clinical and radiographic results can be achieved with an extended trochanteric osteotomy and proximally porous-coated calcar replacement prosthesis.

Cement penetration and primary stability of the femoral component after impaction allografting

This study explored the relationship between the initial stability of the femoral component and penetration of cement into the graft bed following impaction allografting.

Impaction allografting was carried out in human cadaveric femurs. In one group the cement was pressurised conventionally but in the other it was not pressurised. Migration and micromotion of the implant were measured under simulated walking loads. The specimens were then cross-sectioned and penetration of the cement measured.

Around the distal half of the implant we found approximately 70% and 40% of contact of the cement with the endosteum in the pressure and no-pressure groups, respectively. The distal migration/micromotion, and valgus/varus migration were significantly higher in the no-pressure group than in that subjected to pressure. These motion components correlated negatively with the mean area of cement and its contact with the endosteum.

The presence of cement at the endosteum appears to play an important role in the initial stability of the implant following impaction allografting.

A clinical, radiographic, and cost comparison of cerclage techniques: wires vs cables

The cerclage technique is used to secure femoral fractures, allografts, and plates. It is not clear whether wires or cables are better suited for this technique. A retrospective radiographic review of the 6,460 total hip arthroplasties done between 1986 and 2003 was performed. Wires/cables were used in 249 hips. It was found that one cable was broken (0.92%) compared with 11 wires (1.72%) (P < .5373). It was found that there was no statistical difference in Harris hip function or pain scores between patients with wires and those with cables or between those with broken wires/cables and those without broken wires/cables. The Luque wires, which cost 29.79 US dollars each, performed equally to the cables, which cost 275.40 US dollars each, suggesting that wiring may be the preferred cerclage technique.

Mechanical effects of the extended trochanteric osteotomy

BACKGROUND

The extended trochanteric osteotomy was introduced as a safe and effective exposure technique for revision hip surgery; however, intraoperative iatrogenic femoral fractures have been reported. This study examined the effects of the extended trochanteric osteotomy on the torsional strength of the femur with use of cadaver bones. We hypothesized that repair of the osteotomy fragment would restore the torsional strength to that of an intact femur and that an osteotomized femur containing a well-fixed stem would have the same torsional strength as an intact femur with a stem.

METHODS

Fifty-eight cadaveric human femora were divided into five groups, according to the repair technique, to examine the effects of the extended trochanteric osteotomy: intact, osteotomy, repaired osteotomy, implant, and implant-repaired osteotomy. Osteotomy fragments were reattached with use of three double-looped 18-gauge wires. A femoral stem was cemented into the last two groups. Specimens were tested mechanically in rotation until failure. Rotational properties were compared with one-way analysis of variance followed by post hoc pairwise comparisons. Linear regression analysis was performed for bone mineral density and torsional strength.

RESULTS

Torque to failure was reduced by 73% for the specimens in the osteotomy group compared with the intact group (p < 0.0001). Repair of the osteotomy did not improve torque to failure (p > 0.99). Femora in the implant-repaired osteotomy group displayed significantly improved torque-to-failure values compared with the specimens in the osteotomy and repaired osteotomy groups (p < 0.0001). However, the strength of the femora in the implant-repaired osteotomy group remained significantly less than that of the specimens in the implant group (p < 0.007). A significant linear relationship was observed between bone mineral density and torque to failure for femora in the intact (p < 0.006), osteotomy (p < 0.002), and repaired osteotomy (p < 0.001) groups.

CONCLUSIONS

The extended trochanteric osteotomy reduces torsional strength by 73% even when the osteotomy fragment is repaired. Bone mineral density directly affects absolute femoral strength in this model.

Impaction allografting for femoral component revision: clinical update

The technique of cancellous impaction allografting with cement aims to reconstitute a bone-deficient proximal femur while also gaining stable fixation of the femoral prosthesis. Some reports of this technique imply it is a system, requiring not just an exacting surgical method, but also a particular implant design, the polished, double-tapered stem. Other series consider it a surgical technique, and have varied the femoral component design, the method of graft delivery, and other elements of the procedure. Our review evaluates the current literature, with the goal of beginning to ascertain whether published results suggest impaction grafting must be considered a system, requiring a particular stem design, or simply another means to achieve femoral reconstruction in the revision setting. The conclusive answer will require randomized, controlled clinical trials to evaluate particular elements of the procedure, and these studies have yet to be done. However, investigators have shown similarly good short-term to intermediate-term results with various femoral stems at numerous centers. Currently, femoral impaction allografting, whether as a system using particular implant designs or as a surgical technique, is an accepted alternative for revision of a failed femoral component, particularly when bone-stock deficiency is present.

In vitro stability of cemented and cementless femoral stems with compaction

Rigidity of initial fixation is a key factor contributing to the longevity of cemented and cementless femoral components in total hip arthroplasty. The objective of this study was to measure the initial stability of primary cemented and cementless femoral components under load when 15 pairs of cadaveric femurs were prepared by outward compaction of femoral cancellous bone in situ or by conventional extraction broaching. Three-dimensional micromotion was measured at proximal and distal locations on the femoral components using a device with spherical targets and linear variable differential transformers. External loads simulating the stance phases of level walking and stair ascent were applied to the femoral components by a materials test machine. Bone preparation method significantly affected each of the translation and rotation components of micromotion with cemented and cementless fixation. Micromotion with broaching was consistently greater than with compaction. Compared with compaction, the magnitude of the micromotion translation vector for broaching was an average of 3.9 (standard deviation, 3.1) times greater with cemented fixation, and an average of 2.3 (standard deviation, 1.4) times greater with cementless fixation. The results of this study showed the effectiveness of compaction of femoral cancellous bone in improving the initial stability of cemented and cementless femoral components in primary total hip arthroplasty.

The extended trochanteric osteotomy in revision hip arthroplasty: a critical review of 166 cases at mean 3-year, 9-month follow-up

We conducted a retrospective review of 192 consecutive revision hip arthroplasties with an extended proximal femoral osteotomy performed from 1992 through January 1998. Of these osteotomies, 166 had a minimum of 2 years of clinical and radiographic follow-up (range, 2-7.5 years; average, 3 years, 9 months). All patients had a femoral reconstruction with an extended trochanteric osteotomy and an extensively porous-coated, cementless femoral component. The average age at revision was 65.8 years (range, 26-84 years). Of the 166 osteotomies, 2 nonunions (1.2%) and 1 malunion (0.6%) were identified. Seventeen hips (10.2%) required reoperation. Pain and walking scores improved from a mean of 6.5 preoperatively to 9.8 postoperatively. The extended trochanteric osteotomy heals predictably and enhances the surgeons' ability to address many difficult issues encountered in revision arthroplasty.