Cementless revision of total hip arthroplasty using the anatomic porous replacement revision prosthesis

Combined Strut Onlay Allografting, Reduction Osteotomy, and Extensively Porous-Coated Stem for Reconstruction of Severe Femoral Defects During Revision Hip Arthroplasty

BACKGROUND

The purpose of this study is to determine the long-term (up to 27 years) results of a modified technique applying strut allografts combined with a reduction osteotomy over an extensively porous-coated stem.

METHODS

We reviewed the results of 399 revision total hip arthroplasties (for aseptic loosening in 390 hips and septic loosening in 9 hips) in 369 patients (mean age 58 ± 13 years, range 22-65) performed with an extensively porous-coated femoral stem combined with a cortical strut onlay allograft. The mean follow-up was 23 years (range 20-27).

RESULTS

The mean Harris Hip Score was 84 ± 16 points (range 35-100) at the final follow-up. The mean Western Ontario and McMaster Universities Osteoarthritis Index score was 21 ± 16 points (range 12-53) at the final follow-up. The mean University of California Los Angeles activity score was 6.1 points (range 5-8). A Kaplan-Meier survivorship analysis at 23 years of follow-up showed that the survival rate of the femoral component was 95.5% (95% confidence interval 89-98) with aseptic loosening or revision for any reason and it was 91.5% (95% confidence interval 85-95) if septic loosening was included.

CONCLUSION

We found good results in terms of longevity and functional outcome using this modified technique. Future mechanical studies in addition to controlled clinical studies are warranted.

High Incidence of Irradiated Cortical Strut Allograft Resorption Following Revision of Femoral Stems

BACKGROUND

Despite the widespread use of revision total hip arthroplasties using cementless stems and cortical strut allografts, graft resorption has not been explicitly studied.

METHODS

Between 2010 and 2018, 40 femoral strut grafts were used in the revision of femoral stems of 36 patients (18 males and 18 females; average age, 51.9 ± 12.9 years). The mean follow-up was 78.9 ± 37.3 months. Failure was defined as revision surgery for any reason and subsidence of greater than 5 mm.

RESULTS

The survival rate of the stem without the need for revision at 5 years was 95% (mean graft survival time, 10.8 [95% CI, 9.414-12.234] years). Overall survival with graft resorption as the endpoint was 90% at 5 years (mean graft survival time, 8.8 [95% CI, 7.5-10.2] years). Survival with graft nonunion as the endpoint was 90% at 3 years (mean survival time, 11.7 [95% CI, 10.5-12.8] years).

CONCLUSION

The resorption rate increases proportionally to the follow-up duration and can be very severe in a high percentage of cases. Long-term multicenter studies are required to assess the effect of resorption on prosthesis longevity.

Revision total hip arthroplasty in patients with femoral bone loss using tapered rectangular femoral stem: a minimum 10 years' follow-up

BACKGROUND

Revision total hip arthroplasty (THA) remains a significant challenge when there is severe femoral bone loss. The purpose of this study was to evaluate the clinical and radiographic outcomes of revision THA in patients with femoral bone loss treated with Zweymüller SLR-Plus stem.

METHODS

A retrospective review of 82 patients who underwent revision THA using tapered rectangular femoral stem between 1997 and 2007 was undertaken. Of the 82 patients, 9 patients were lost to follow-up and were excluded from the study. The most common reason for revision was aseptic loosening (92%), periprosthetic femur fracture (5%), and infection (3%). Bone loss was categorised preoperatively according to the Paprosky classification. The mean clinical follow-up was 14 years (range 10-19 years). Their mean age at the time of index surgery was 54.7 ± 15.3 (range 30-82) years.

RESULTS

The mean Harris Hip Score was significantly improved at final follow-up (68.1 ±10.3) compared with that before the revision surgery (30.4 ± 7.7) (p < 0.0001). Of the 75 stems, 69 (92%) stems were radiographically stable at the last evaluation. Among the 69 stems, 64 hips (85%) had radiographic evidence of bone ingrowth and 5 (5%) had stable fibrous fixation of the stem. Among the 7 hips that were re-revised, 5 hips were re-revised for aseptic loosening, whereas 2 were re-revised for an infection. Kaplan-Meier survivorship analysis, with removal of the stem for any cause as the endpoint, revealed that the 15-year rate of survival of the components was 90% (95% CI, 0.83-0.97).

CONCLUSION

Revision THA in patients with proximal femoral bone loss using Zweymüller SLR-Plus stem led to a high rate of osseointegration of the stem and good clinical results at long-term follow-up.

Bone restoration after revision hip arthroplasty with femoral bone defects using extensively porous-coated stems with cortical strut allografts

Background

Stress shielding and bone loss of the femur are of great concern after revision total hip arthroplasty (THA) with extensively porous-coated stems, especially in a femur with already bone loss. The femoral bone remodeling patterns after revision THA with femoral bone defects using extensively porous-coated stems with cortical strut allografts remain unclear.

Methods

We retrospectively reviewed 47 patients who underwent revision THA using extensively porous-coated stems combined with cortical strut allografts and 75 patients without allografts. The minimum follow-up was 2 years. Femoral bone remodeling signs, including stress shielding, bone restoration in bone defect area, distal cortical hypertrophy, and femoral width, were compared between patients with and without cortical strut allografts. Clinical outcomes were also compared between two groups.

Results

Patients with cortical strut allografts showed less severe stress shielding (P = 0.01) than patients without allografts. Patients with allografts had more osseous restoration in bone defect area than patients without allografts (63.8% vs 30.7%, P < 0.001). Femoral width was significantly higher in femur with allografts than in femur without allografts at the immediate postoperative stage and latest follow-up (both P < 0.001). The hip function score, re-revision rate, and complications were comparable between two groups.

Conclusion

The application of cortical strut allografts can decrease the severity of stress shielding, augment osseous restoration in bone defect area and improve femoral bone stock after revision THA using extensively porous-coated stems.

High Survivorship With Cementless Stems and Cortical Strut Allografts for Large Femoral Bone Defects in Revision THA

BACKGROUND

Numerous studies have investigated the clinical and radiographic results of revision THAs with use of cementless stems and cortical strut allografts. However, to our knowledge, no long-term followup studies have evaluated patients undergoing revision THA with use of cortical strut allografts where the allografts provided the primary stability for extensively coated femoral stems in the presence of extensive femoral diaphyseal bone defects.

QUESTION/PURPOSES

We performed this study to determine (1) validated outcomes scores; (2) radiographic signs of fixation and allograft healing; (3) frequency of complications; and (4) survivorship of the components after use of cortical strut onlay allografts in Types IIIB and IV femoral diaphyseal bone defects.

METHODS

Between 1994 and 2003, we performed 140 revision THAs in 130 patients with Paprosky Types IIIB and IV femoral diaphyseal defects. The patients were treated using extensively coated femoral stems and cortical strut allografts because primary axial or rotational stability could not be achieved without grafting. Ten of the patients (10 hips; 7.7%) were lost to followup or died before 10 years; the remaining 120 patients (130 hips) represent the study group in this retrospective study. There were 66 men and 54 women. Their mean age at the time of index surgery was 59 ± 18 years (range, 36-67 years). The primary diagnosis was predominantly osteonecrosis of the femoral head (53%). The most common reason for revision was aseptic loosening (97%), followed by periprosthetic fracture (3%). The mean time from primary to revision THA was 12 years (range, 8-27 years). The mean duration of followup was 16.1 years (range, 12-20 years).

RESULTS

The mean Harris hip score was 39 ± 10 points before revision and improved to 86 ± 14 points at 16 years followup (p = 0.02). The mean preoperative WOMAC score was 62 ± 29 (41-91) points and improved to 22 ± 19 (11-51) points at 16 years followup (p = 0.003). Of the 130 stems, 113 (87%) had bone ingrowth, five (4%) had stable fibrous ingrowth, and 12 (9%) were unstable. All allografts were incorporated. Four hips (3%) had a displaced femoral shaft fracture at the stem tip; four (3%) had a postoperative dislocation; and six (5%) had early postoperative infection. Kaplan-Meier survivorship analysis, with revision or radiographic failure as the endpoint, revealed that the 16-year rate of survival of the components was 91% (95% CI, 0.88%-0.96%).

CONCLUSION

Supportive cortical strut onlay allografts provided high survivorship beyond 12 years of followup in revision THAs. Future studies might compare this approach with allograft-prosthesis composites, proximal femoral replacement, or modular fluted, tapered stems.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Mid-Term Outcomes and Complications with Cementless Distal Locking Hip Revision Stem with Hydroxyapatite Coating for Proximal Bone Defects and Fractures

We revised the first 100 revision total hip arthroplasties using a cementless distal locking revision stem conducted in our referral centre. Average follow-up was 9.2 years (range: 5.5-12 years). Harris Hip Score improved from 42.5 to 81.6, and none had thigh pain at last follow-up. No significant stress shielding, osteolysis, or radiologic loosening was found. All patients showed radiological evidence of secondary implant osseointegration. Overall survival was 97% with three patients being revised: two stem ruptures and one subsidence. We could trace these complications to technical errors. These findings suggest that a diaphyseal fixation of the revision stem with distal locking can provide the needed primary axial and rotational stability of the prosthesis. This would allow further bony ingrowth, enhanced by the hydroxyapatite coating.

Strut grafts in revision hip arthroplasty faced with femoral bone defects: an experimental analysis

PURPOSE

In total hip arthroplasty fixation of revision stems can be demanding due to femoral bone loss. Strut grafts are often used for bone augmentation and stabilization of the newly inserted prosthesis. The aim of this study was to assess the effect of strut grafts on primary stability under various stem fixation conditions.

METHODS

Two different revision stems (cylindrical and conical shape) were implanted into synthetic femora. Following a semicircular transfemoral osteotomy, three deficient femoral bearings were simulated (bony lid reattached with cable wires; weakened lid reattached with cable wires; strut grafts placed to the weakened lid with cable wires). Relative micro-movements were measured between prostheses and bones due to an axial moment applied to the stems.

RESULTS

Relative movements correlated to the stem shape. The cylindrical stem showed higher movements increasing significantly with a weakened bony lid and portrayed a slight decrease of movements with strut graft application. No unequivocal influence of the weakened lid could be detected for the conical implant. Strut graft application did not show an additional stabilizing effect.

CONCLUSIONS

The primary stability of the cylindrical fixation concept decreases with impaired fixation conditions of the femur. A clear restabilizing effect with strut grafts could not be proven. A decrease of primary stability due to the impaired bone could not be observed for the conical stem shape. Additionally, strut grafts do not enhance fixation for this stem shape. We conclude that surgeons should not rely on a stabilizing effect of strut grafts in revision hip surgery.

Custom uncemented revision stems based on a femoral classification

From the outcome of 175 cases, a group of 4 types of custom-designed HA-coated hip stems, based upon an incremental scale of bone condition, was demonstrated to be sufficient for use with the variety of cavitary defects encountered in revision hip surgery. Harris Hip Score evaluation showed a significant improvement in hip pain and function. Radiographic measurements of axial migration over a 4-year period were less than 2 mm. The migration data were similar across the 4 types of revision stem. A follow-up using DEXA scans showed preservation of bone in all regions up to 4 years, which justifies the design rationale for the close fit of the stems in the proximal region in achieving initial stability and strain transfer.

Reconstruction of femoral defects in revision hip surgery: risk of fracture and stem migration after impaction bone grafting

The use of impaction bone grafting during revision arthroplasty of the hip in the presence of cortical defects has a high risk of post-operative fracture. Our laboratory study addressed the effect of extramedullary augmentation and length of femoral stem on the initial stability of the prosthesis and the risk of fracture. Cortical defects in plastic femora were repaired using either surgical mesh without extramedullary augmentation, mesh with a strut graft or mesh with a plate. After bone impaction, standard or long-stem Exeter prostheses were inserted, which were tested by cyclical loading while measuring defect strain and migration of the stem. Compared with standard stems without extramedullary augmentation, defect strains were 31% lower with longer stems, 43% lower with a plate and 50% lower with a strut graft. Combining extramedullary augmentation with a long stem showed little additional benefit (p = 0.67). The type of repair did not affect the initial stability. Our results support the use of impaction bone grafting and extramedullary augmentation of diaphyseal defects after mesh containment.

Prospective evaluation of total hip arthroplasty with a cementless, anatomically designed, porous-coated femoral implant: mean 11-year follow-up

The performance of an anatomically designed femoral implant with porous titanium mesh coating was assessed in patients undergoing total hip arthroplasty. The stem, with built-in 12 degrees anteversion, was implanted in neutral position relative to the long axis of the femur through a cementless press-fit application. The only requirement was the presence of sufficient thickness within the cortical bone of the femoral metaphysis to support the stem. Ninety-one evaluable patients were followed up for a minimum of 10 years. Patients tolerated weight-bearing activity within 24 hours after surgery. Only 1 femoral component required revision because of loosening. Most patients showed uniform bony ingrowth. Quality of life was markedly improved. The anatomically designed, porous-coated implant provides robust performance which has general utility in a wide range of patients.

Revision of cemented hip arthroplasty using a hydroxyapatite-ceramic-coated femoral component

We report the clinical and radiological outcome of 86 revisions of cemented hip arthroplasties using JRI-Furlong hydroxyapatite-ceramic-coated acetabular and femoral components. The acetabular component was revised in 62 hips and the femoral component in all hips. The mean follow-up was 12.6 years and no patient was lost to follow-up.

The mean age of the patients was 71.2 years. The mean Harris hip and Oxford scores were 82 (59 to 96) and 23.4 (14 to 40), respectively. The mean Charnley modification of the Merle d’Aubigné and Postel score was 5 (3 to 6) for pain, 4.9 (3 to 6) for movement and 4.4 (3 to 6) for mobility. Migration of the acetabular component was seen in two hips and the mean acetabular inclination was 42.6°. The mean linear polyethylene wear was 0.05 mm/year. The mean subsidence of the femoral component was 1.9 mm and stress shielding was seen in 23 (28%) with bony ingrowth in 76 (94%). Heterotopic ossification was seen in 12 hips (15%). There were three re-revisions, two for deep sepsis and one for recurrent dislocation and there were no re-revisions for aseptic loosening. The mean EuroQol EQ-5D description scores and health thermometer scores were 0.69 (0.51 to 0.89) and 79 (54 to 95), respectively. With an end-point of definite or probable loosening, the probability of survival at 12 years was 93.9% and 95.6% for the acetabular and femoral components, respectively. Overall survival at 12 years, with removal or further revision of either component for any reason as the end-point, was 92.3%.

Our study supports the continued use of this arthroplasty and documents the durability of hydroxyapatite-ceramic-coated components.

The initial stability of an exeter femoral stem after impaction bone grafting in combination with segmental defect reconstruction

Bone impaction grafting of the femur is associated with more complications when segmental defects are present. The effect of segmental defect repair on initial stem stability was studied in an in vitro study with fresh-frozen goat femora. A standardized medial segmental defect was reconstructed using a cortical strut or a metal mesh. As controls, we used intact femora and femora with a nonreconstructed defect. In all 4 groups, impacted bone grafting was performed in combination with a cemented Exeter stem. Each group contained 5 femora. Reconstructions were dynamically loaded up to 1,500 N. Migration was measured with Roentgen stereophotogrammetric analysis. All cases with a nonreconstructed segmental defect failed into excessive varus rotation. None of the femora with a reconstructed defect failed. Cortical struts and metal meshes were equally effective in creating a stable stem construction (varus rotation, 2.89 +/- 2.27 and 2.27 +/- 0.57, respectively). Reconstructions with a metal mesh were more reproducible, although the obtained stability was significantly lower (P<.01) when compared with impaction grafting in an intact femur (varus rotation, 0.58 +/- 0.36).

Assessment of bone graft substitutes in autopsy implant retrievals of the acetabulum in total hip arthroplasty

Two autopsy retrievals of acetabular reconstruction with different bone graft substitutes were analyzed. One patient underwent surgery with hydroxyapatite (HA) granules, and the other with demineralized bone chips. Incorporation occurred with the biomaterial bone-graft substitute HA primarily in the superior part of the acetabulum, where the HA was in contact with host cortical bone. No bony union occurred with the demineralized bone chips because of motion and migration of the acetabular cup. No bone incorporation of either bone-graft substitute was observed in the medial wall defects in both patients. There were two important findings: (1) the 3- to 8-mm depth and 70% to 75% surface of union of the HA bone graft substitute to host cortical bone was the same as seen with morselized, fresh-frozen bone graft; and (2) union of graft material to host bone was dependent on secure fixation of the acetabular construct.

Functional outcome after revision hip arthroplasty: a metaanalysis

The current study systematically reviews the literature describing patient outcomes after revision total hip arthroplasties using conventional global hip score ratings. Two thousand one hundred thirty-seven English-language articles published from 1966 through 2000 were identified through a computerized literature search and bibliography review. A three-step filter process was used to identify articles to be included in the metaanalysis. Forty-two articles with 2578 patients had data abstracted for the analysis. Metaanalysis of global hip scores was done using a fixed effects model with the assumption that the variances of each measurement were identical across studies. Thirty-nine articles reporting on 46 cohorts progressed through three filters and went to data extraction and analysis. Revision total hip arthroplasty is a reasonably safe and effective procedure for failed hip replacement Based on this exploratory analysis revision hip procedures seem to have comparable longevity, to primary hip replacement but appear to have slightly lower functional outcome (as measured by global hip scores), and slightly higher morbidity and mortality rates than primary procedures. Inconsistent reporting in the original studies limited exploration of other factors that may have affected outcomes.

Long-term results after cemented revision of the femoral component in total hip arthroplasty

The need for revision total hip arthroplasty has been increasing. The early results have been poor, and different revision techniques have been introduced. We report our results of 84 consecutive cemented first-time revisions of femoral components performed from 1981 through 1988 using a long-stem revision component. The average time to follow-up was 11.4 years (range, 7.9-15.0 years). Patients with 47 revisions had died; 2 of these had been rerevised. Two additional patients were lost to follow-up for other reasons. Of the living patients, 12 had been rerevised, leaving 23 patients (23 hips) for complete follow-up evaluation, including clinical and radiographic assessment. Of 23 patients, 15 reported no pain, 4 had only slight pain, and 4 had more severe pain. In 4 cases, there were definite radiographic signs of loosening of the femoral component. Kaplan-Meier survivorship analysis showed an overall 10-year survival of the femoral component of 77.9%. Using rerevision because of aseptic loosening or definite radiographic loosening as endpoint, the 10-year survival was 80.7%. Simple recementation is well indicated in elderly patients with only minor bone loss.

Supportive strut grafts for diaphyseal bone defects in revision hip arthroplasty

Large femoral cortical strut allografts were used to provide structural support of the femur in 20 patients in whom uncemented, extensively porous-coated, press-fit revision femoral stems were applied. The mean followup was 4.7 years. Radiographic analysis of the patients who had revision surgery revealed that in all 20 patients, the cortical femoral strut allografts showed incorporation. Small areas of graft resorption were observed in only two patients. Seventeen of the uncemented femoral revision stems radiographically showed bone ingrowth. Three of the revision femoral stems were interpreted as being fixed only by fibrous ingrowth after early subsidence after surgery. There were no reoperations. Before surgery, all patients were unable to walk and had severe pain. At followup, all patients were ambulatory and had considerable improvement in pain relief and in their ability to walk. The mean Harris hip score after surgery was 75 (range, 57.5-92). Complications consisted of one peroneal nerve palsy, which resolved; one deep venous thrombosis; one gastrointestinal ulcer; and one case of pneumonia. Supportive cortical strut allografts represent an alternative to the use of circumferential bulk allografts and total femoral replacements in patients with large combined proximal and diaphyseal bone defects.