Excellent results of HA coating on a grit-blasted stem: 245 patients followed for 8-12 years

We report the outcome of a grit-blasted titanium stem designed for press-fit insertion and entirely plasma sprayed with HA. During the years 1988-1993, we performed 323 primary total hip replacements in 276 patients (189 women) with a HA-coated prosthesis. Their mean age was 48 (15-79) years. During the follow-up, 12 patients died. 19 other patients did not attend the follow-up examination, but had no major symptoms according to telephone interviews and written replies. Thus, 245 patients (291 hips) were followed for a mean of 10 (8-12) years with radiographic and clinical examinations. Only 1 stem was revised due to mechanical failure. None were revised because of infection. Osteolysis was significantly associated with wear, and wear was significantly associated with the size of the femoral head. We found a small amount of proximal bone loss (37/291) and a low incidence of distal hypertrophy of the bone (23/291). These observations indicate an essentially physiological weight distribution from the stem to the femoral bone. The changes in the bone confirmed that the femoral component was well fixed in asymptomatic patients. To conclude, we found excellent 8-12-year results with a fully HA-coated femoral prosthesis designed for press-fit insertion.     

Excellent results of HA coating on a grit-blasted stem: 245 patients followed for 8-12 years

We report the outcome of a grit-blasted titanium stem designed for press-fit insertion and entirely plasma sprayed with HA. During the years 1988-1993, we performed 323 primary total hip replacements in 276 patients (189 women) with a HA-coated prosthesis. Their mean age was 48 (15-79) years. During the follow-up, 12 patients died. 19 other patients did not attend the follow-up examination, but had no major symptoms according to telephone interviews and written replies. Thus, 245 patients (291 hips) were followed for a mean of 10 (8-12) years with radiographic and clinical examinations. Only 1 stem was revised due to mechanical failure. None were revised because of infection. Osteolysis was significantly associated with wear, and wear was significantly associated with the size of the femoral head. We found a small amount of proximal bone loss (37/291) and a low incidence of distal hypertrophy of the bone (23/291). These observations indicate an essentially physiological weight distribution from the stem to the femoral bone. The changes in the bone confirmed that the femoral component was well fixed in asymptomatic patients. To conclude, we found excellent 8-12-year results with a fully HA-coated femoral prosthesis designed for press-fit insertion.     

Total Hip Arthroplasty With a Fully Hydroxyapatite-Coated Stem: A Cohort Study During 23-28 Years

Background

Long-term results of a hydroxyapatite (HA)-coated stem are sparse. We have followed a cohort of patients operated with a grit-blasted titanium stem designed for press-fit insertion and entirely plasma-sprayed with HA up to 28 years.

High osteolysis and revision rate with the hydroxyapatite-coated ABG hip prostheses: 65 hips in 56 young patients followed for 5-9 years

BACKGROUND: There are few reports on the outcome of uncemented HA-coated cups in young patients. PATIENTS: I evaluated the 7-year (5-9) results of HA-coated hip prosthesis (ABG, Stryker) in a consecutive series of 65 primary arthroplasties on 56 patients (mean age 44 years). 2 patients were lost to follow-up and 3 died. RESULTS: The cumulative survival rate with revision for any reason as endpoint at 9 years was 98% (95% CI, 96-100) for the stem, 69% (61-77) for the acetabular metal backing, and 59% (50-67) for the polyethylene liner. 15 of 65 cups were revised on average 6 years after the primary operation and 3 more are planned. Revisions were done in 3 hips because of loosening and migration of the cup, and in 12 hips because of wear and progressive osteolysis around stable components. Only hips with migration had clinical symptoms. Visual inspection of polyethylene liners revealed wear of the articulation in all cases, loosening of the locking mechanism in 10 cases and nonarticular surface deformity in 7 hips. All original stems are in situ although femoral osteolysis was seen in 12 cases and 1 hip was reoperated because of periprosthetic traumatic fracture. Despite the high revision rate, the clinical improvement was good: the average pre- and postoperative Harris Hip Scores at the most recent follow-up were 41 and 90, respectively. INTERPRETATION: While the results on the femoral side were good, the survival rates of the acetabular cups were poor and we stopped using ABG I hip prostheses.     

Excellent results with femoral revision surgery using an extensively hydroxyapatite-coated stem: 59 patients followed for 10-16 years

BACKGROUND: The outcome of femoral component revision with either cemented or proximally coated stems has been disappointing, but revision with extensively coated stems has been promising. We report long-term outcome of a grit-blasted titanium stem entirely plasma sprayed with hydroxyapatite (HA), in femoral revision surgery. PATIENTS AND METHODS: During 1988 to 1993, we performed 66 femoral revisions in 65 patients (49 women) aged mean 58 (28-86) years. 3 patients died before the 10-year follow-up and 4 did not come for the follow-up examination because they had no hip problems, as confirmed by telephone and by a written reply. 1 of these, however, was previously controlled at 10 years. Thus, 59 patients (60 hips) were followed by clinical and radiographic analysis for 10-16 years after femoral stem revision. RESULTS: 1 stem was re-revised due to mechanical failure, and none were revised because of infection. We noticed a low degree of proximal bone loss and a low incidence of distal bone hypertrophy. These observations indicate no significant net transfer of stress proximally to distally, and a somewhat physiological weight distribution from the stem to the femoral bone. The bone changes confirmed a well-fixed femoral component in asymptomatic patients. INTERPRETATION: Our findings indicate good long-term results with a fully HA-coated stem in femoral revision surgery.     

High osteolysis and revision rate with the hydroxyapatite-coated ABG hip prostheses

Background There are few reports on the outcome of uncemented HA-coated cups in young patients.

Patients I evaluated the 7-year (5-9) results of HA-coated hip prosthesis (ABG, Stryker) in a consecutive series of 65 primary arthroplasties on 56 patients (mean age 44 years). 2 patients were lost to follow-up and 3 died.

Results The cumulative survival rate with revision for any reason as endpoint at 9 years was 98% (95% CI, 96-100) for the stem, 69% (61-77) for the acetabular metal backing, and 59% (50-67) for the polyethylene liner. 15 of 65 cups were revised on average 6 years after the primary operation and 3 more are planned. Revisions were done in 3 hips because of loosening and migration of the cup, and in 12 hips because of wear and progressive osteolysis around stable components. Only hips with migration had clinical symptoms. Visual inspection of polyethylene liners revealed wear of the articulation in all cases, loosening of the locking mechanism in 10 cases and nonarticular surface deformity in 7 hips. All original stems are in situ although femoral osteolysis was seen in 12 cases and 1 hip was reoperated because of periprosthetic traumatic fracture. Despite the high revision rate, the clinical improvement was good: the average pre- and postoperative Harris Hip Scores at the most recent follow-up were 41 and 90, respectively.

Interpretation While the results on the femoral side were good, the survival rates of the acetabular cups were poor and we stopped using ABG I hip prostheses.     

Eight-year results of hydroxyapatite-coated hip arthroplasty

Ninety hips in 82 patients using Omnifit hydroxyapatite (HA)-coated prosthesis were followed for at least 7 years. All stems were stable at the final follow-up. However, aseptic loosening was found in 8 cups and 6 of them were revised. Two polyethylene wear were treated with inserts exchanged. The mechanical failure rate was 11.4% and the combined failure rate was 14.3% for HA-coated cup. Four other cups with wear and osteolysis without loosening or pain and 2 cups with polyethylene wear without osteolysis were still under observation. Our findings suggest that hip arthroplasties with HA coating on the smooth surface of a titanium cup is not reliable. The mid-term result of HA-coated stem is as good as that of porous-coated stem.     

High osteolysis and revision rate with the hydroxyapatite-coated ABG hip prostheses65 hips in 56 young patients followed for 5–9 years

Background?There are few reports on the outcome of uncemented HA-coated cups in young patients.Patients?I evaluated the 7-year (5–9) results of HA-coated hip prosthesis (ABG, Stryker) in a consecutive series of 65 primary arthroplasties on 56 patients (mean age 44 years). 2 patients were lost to follow-up and 3 died.Results?The cumulative survival rate with revision for any reason as endpoint at 9 years was 98% (95% CI, 96–100) for the stem, 69% (61–77) for the acetabular metal backing, and 59% (50–67) for the polyethylene liner. 15 of 65 cups were revised on average 6 years after the primary operation and 3 more are planned. Revisions were done in 3 hips because of loosening and migration of the cup, and in 12 hips because of wear and progressive osteolysis around stable components. Only hips with migration had clinical symptoms. Visual inspection of polyethylene liners revealed wear of the articulation in all cases, loosening of the locking mechanism in 10 cases and nonarticular surface deformity in 7 hips. All original stems are in situ although femoral osteolysis was seen in 12 cases and 1 hip was reoperated because of periprosthetic traumatic fracture. Despite the high revision rate, the clinical improvement was good: the average pre- and postoperative Harris Hip Scores at the most recent follow-up were 41 and 90, respectively.Interpretation?While the results on the femoral side were good, the survival rates of the acetabular cups were poor and we stopped using ABG I hip prostheses.     

Excellent results with femoral revision surgery using an extensively hydroxyapatite-coated stem: 59 patients followed for 10-16 years

Background The outcome of femoral component revision with either cemented or proximally coated stems has been disappointing, but revision with extensively coated stems has been promising. We report long-term outcome of a grit-blasted titanium stem entirely plasma sprayed with hydroxyapatite (HA), in femoral revision surgery.

Patients and methods During 1988 to 1993, we performed 66 femoral revisions in 65 patients (49 women) aged mean 58 (28-86) years. 3 patients died before the 10-year follow-up and 4 did not come for the follow-up examination because they had no hip problems, as confirmed by telephone and by a written reply. 1 of these, however, was previously controlled at 10 years. Thus, 59 patients (60 hips) were followed by clinical and radiographic analysis for 10-16 years after femoral stem revision.

Results 1 stem was re-revised due to mechanical failure, and none were revised because of infection. We noticed a low degree of proximal bone loss and a low incidence of distal bone hypertrophy. These observations indicate no significant net transfer of stress proximally to distally, and a somewhat physiological weight distribution from the stem to the femoral bone. The bone changes confirmed a well-fixed femoral component in asymptomatic patients.

Interpretation Our findings indicate good long-term results with a fully HA-coated stem in femoral revision surgery. ▪     

Excellent results from proximally HA-coated femoral stems with a minimum of 6 years follow-up: a prospective evaluation of 100 patients

BACKGROUND: There have been few reports on the mid- and long-term follow-up results of the proximally HA-coated femoral stem. We evaluated this type of stem prospectively, with 6-12 years of follow-up. METHODS: The survival rate, Harris hip score and radiographic features of 106 hips in 100 consecutive patients were evaluated. The mean age at operation was 51 years (SD 8.2). RESULTS: The mean Harris hip score at the time of the latest follow-up was 95 points. Spot welds occurred in 95% of the patients and were first observed at a mean follow-up of 1.4 years in one or more of the Gruen regions, corresponding to the coated part of the femoral stem. A higher grade of stress shielding correlated with a less favorable Harris hip score and pain subscore. According to the criteria of Engh, all stems were graded as stable and durable bone-ingrown. No femoral component was revised. INTERPRETATION: At an average follow-up of 8 years, this proximally HA-coated femoral component showed favorable clinical and radiological outcome and excellent survivorship.     

Cementless mallory-head HA-coated hip arthroplasty for osteoarthritis in hip dysplasia

Sixty-three cementless Mallory-Head HA-coated femoral prostheses (Biomet, Warsaw, IN) were used in primary total hip arthroplasty in 50 patients with osteoarthritic hips because of congenital hip dysplasia. The implanted cup was also cementless (41 Harris Galante and 22 Ringlock). The patients were followed up for a mean period of 75.1 months (range, 44-110). Clinical and radiologic analysis were performed. Harris Hip Score increased from 42 to 90 points; 97% of the patients had no or only mild pain, and limping decreased from 90% to 20%. Complications were marginal: no infections, one habitual dislocation, one peroperative fracture of the femur, and one transient ischiadic nerve palsy. Two HG cups were revised for augmented polyethylene wear. Radiographically, no subsidence of the prosthesis or bone atrophy of the proximal femur could be detected. No correlations were found between the radiologic phenomena and the clinical outcome, but the tightness of the prosthesis fit had a definitive influence on the radiographic bone remodeling pattern. The cementless Mallory-Head HA-coated femoral prosthesis shows excellent clinical and radiological mid-term results in osteoarthritic hip dysplasia patients. There was no need for the use of a specially designed dysplasia femoral prosthesis.     

Ten- to twelve-year follow-up of the furlong hydroxyapatite-coated femoral stem and threaded acetabular cup in patients younger than 65 years

We reviewed 82 patients who had 92 primary Furlong uncemented hydroxyapatite (HA)-coated total hip replacements inserted between 1988 and 1992. All patients had the Furlong HA-coated stem and screw in acetabular cup with a 28-mm alumina oxide ceramic modular head. The mean age at the time of primary total hip arthroplasty was 54 years (range, 31-67 years). At 10 years, we reviewed 64 patients (72 total hip arthroplasties). Eight had died (10 total hip arthroplasties), 3 could not attend for follow-up, 2 were lost to follow-up, and 5 were revised (2 for infection and 3 for acetabular loosening and recurrent dislocation). We conclude that the Furlong HA-coated total hip replacement is a good prosthesis for patients younger than 65 years, with a cumulative survival rate of 94.29% at 10 to 12 years using revision as the end point.     

Tissue reactions around a hydroxyapatite-coated hip prosthesis: Case report of a retrieved specimen

Bone reactions were studied around a titanium, hydroxyapatite (HA)-coated Osteonics (Allendale, NJ) bipolar hip prosthesis, which was revised for severe midthigh pain 4 years after implantation. Inspection of the retrieved prosthesis using a dissecting microscope revealed scarce remnants of a coating-like material on the surface of the prosthesis; however, histology of this layer and histology of the bony side of the bone—HA interface failed to reveal any remnants of an HA coating. The interface was covered predominantly by trabecular bone, which closely followed the contour of the prosthesis, and was partly woven nonmineralized bone. At locations where mineralized bone faced the prosthesis, many small dark titanium wear particles were found. Similar particles were found in macrophages in the intertrabecular medullary space. Polyethylene wear particles were specifically located in macrophages in a soft tissue interface at more distal levels along the stem of the prosthesis. Although the observations presented in this case cannot be generalized, it clearly shows that the HA coating layer had completely disappeared after 4 years. More detailed retrieval studies and longer clinical follow-up studies are needed before a final evaluation of the behavior of HA coatings and long-term fixation of HA-coated prostheses can be made.     

Gute langfristige Nachuntersuchungsergebnisse einer zementierten Titan-Geradschaftprothese

A higher-than-average rate of aseptic loosening has been postulated to be associated with the combination of a titanium stem and bone cement. In this prospective follow-up study we therefore investigated our first consecutive series of 250 implantations of a cemented femoral shaft prosthesis made of titanium alloy (BiCONTACT((R)), Aesculap, Tuttlingen, Germany).Average time of follow-up evaluation was 9.7 years (range 8.7-10.3 years). At follow-up, mean patient age was 81 years; 89 patients with 93 hips have deceased and two could not be located. Follow-up rate was 98.7% for the patients still alive at time of follow-up evaluation. Five patients have been revised, two for infection and one for aseptic loosening of a varus-malaligned stem; two radiologically well-fixed stems had been revised during acetabular revision. Survival estimate showed a calculated cumulative survival rate of 97.5% after 11 years [confidence limits: 99.0% (upper) and 94.1% (lower)]. The average Harris hip score at time of follow-up was 82.25 points.Radiologically, signs of loosening could be detected in 3 stems: in one case varus malalignement deteriorated with time and in 2 cases osteolyses developed together with significant polyethylene wear. All 3 patients experienced only mild pain and revision had not been indicated so far. In conclusion, the long-term follow-up results with this cemented titanium femoral component are encouraging and are comparable to other successful cemented femoral components in primary total hip arthroplasty. No increased risk for aseptical loosening was associated to the combination of titanium and cement in this specific stem. Design parameters seem to play an important role in the development of aseptic loosening in cemented titanium stems.     

Failure of HA coating on a gritblasted acetabular cup: 155 patients followed for 7-10 years

We report the outcome of 191 acetabular gritblasted titanium cups with a hemispherical design for press-fit insertion and coated with hydroxyapatite. The prosthesis was made of gritblasted titanium entirely coated with hydroxyapatite. 155 patients aged 15-78 years were operated on during the years 1991-1993 and followed for 7-10 years. During this period, 39 cups were revised because of mechanical loosening, a further 9 had radiolucent lines and 2 focal osteolysis. None of these 11 patients had clinical symptoms. Failure was associated with age, wear and radiolucency/osteolysis. At revision, we found that the soft tissues were discolored, and that most of the coating had disappeared. This design of hydroxyapatite-coated cups has a high rate of debonding and failure.     

Preoperative radiotherapy without femoral shielding for prevention of heterotopic ossification in hydroxyapatite-coated hip prostheses

Twenty-seven consecutive patients at high risk of developing heterotopic ossifications (HO) after implantation of a hydroxyapatite (HA)-coated hip prosthesis were irradiated with a single dose of 7 Gy, at least 4 h before the operation. The femoral stem was not shielded during radiotherapy (RT). After a median follow-up of 14.8 months, no clinically significant HO could be found, while 12 (52%) patients in this high-risk population had only minor HO (grade I). No reoperation was needed, and no evidence of prosthesis migration was observed. We conclude that single-dose, preoperative RT for HA-coated hip prosthesis can effectively inhibit HO. Not blocking the femoral stem does not result in prosthesis migration. Received: 20 March 2000     

The uncemented Bi-Contact total hip arthroplasty

We reviewed a consecutive series of 153 uncemented Bi-Contact (Aesculap, Tuttlingen, Germany) total hip arthroplasties (THAs) in 138 patients who had been followed for at least 5 years (mean, 6.8 years; range, 5-9 years). The Bi-Contact uncemented THA consists of a straight femoral stem made of titanium alloy. The proximal portion of the stem is titanium plasma-sprayed. The cup is press-fit with or without hydroxyapatite coating with a facility for anchoring screws with a snap-fit polyethylene liner. The mean age of the patients was 70.8 years (range, 41-94 years). The mean preoperative Harris hip score of 41 (range, 20-80) improved postoperatively to a mean of 92 (range, 56-96). Three acetabular cups were revised for aseptic loosening, and 1 cup was revised for recurrent dislocation. To date, none of the stems have been revised for aseptic loosening. Radiographic evaluation of the remaining 149 hips revealed that the acetabular cup was stable in 146 hips and possibly unstable in the remaining 3 cases with nonprogressive osteolysis behind the cup. None of the stems showed any evidence of instability. Using the recommendation of revision as the endpoint, the cumulative survival for the prosthesis was 97.3% at a mean follow-up of 6.8 years (95% confidence interval, 95.9-99.4), with stem survival of 100%. In the medium-term, these results are comparable to cemented primary THA and justify the continued use of this prosthesis.     

短柄全髋关节置换术治疗中青年股骨头坏死患者的近期疗效

 目的 评价陶瓷对陶瓷短柄全髋关节置换术治疗中青年股骨头坏死晚期患者的近期疗效。方法 2009年12月至2011年3月接受陶瓷对陶瓷短柄初次全髋关节置换术治疗的中青年股骨头坏死患者40例(43髋),男 23例,女17例;年龄27～55岁,平均40.5岁。Steinberg分期均为Ⅳ期以上。29例采用后外侧入路,11例采用前侧入路。术后3、6、12个月及以后每年随访1次,摄骨盆正位及髋关节侧位X线片,测量假体下沉距离;采用Harris髋关节评分和WOMAC骨关节炎指数评估关节功能。结果 38例(41髋)得到随访,随访时间21～36个月,平均31.3个月。末次随访X线片上假体位置较术后即刻下沉(0.68±2.90) mm,差异无统计学意义(t=1.51,P=0.139)。术后髋关节疼痛均明显改善或消失,Harris髋关节评分由术前平均(38.7±12.1)分提高至末次随访(95.2±4.49)分,WOMAC骨关节炎指数由术前平均66.7±12.0降至末次随访12.8±5.6,差异均有统计学意义。随访期间未发生股骨颈骨折、感染、肺栓塞等严重并发症,无假体关节脱位、松动及假体感染。结论 短柄全髋关节置换术可更多地保留骨量,假体初始稳定性好,全陶瓷头衬配伍的磨损率低,近期疗效佳,假体相关并发症少。     

Cementless total hip arthroplasty with a tapered, rectangular titanium stem and a threaded cup: a minimum ten-year follow-up

BACKGROUND: We report the results of cementless total hip arthroplasty with a tapered, rectangular titanium stem that was introduced in 1979 and continues to be used today with only minor changes. The aim of the design is to achieve primary stability to resist rotational and axial forces through precision rasping and press-fit implantation of a tapered, rectangular femoral component. METHODS: Between October 1986 and November 1987, 208 total hip arthroplasties with insertion of a tapered, rectangular titanium stem and a threaded cup without cement were performed in 200 consecutive patients (average age, sixty-one years; range, twenty-two to eighty-four years). RESULTS: At the time of the latest follow-up, fifty-one patients (fifty-two hips) had died and sixteen patients had been lost to follow-up, leaving 133 patients. Twelve hips had been revised, two in patients who subsequently died, leaving 123 living patients without revision. The median follow-up time was 120.7 months. Five cups needed revision surgery because of aseptic loosening; two, because of massive polyethylene wear; one, because of posttraumatic migration; and one, because of breakage. Three femoral stems were revised: one because of malpositioning (the reoperation was done five days after implantation); one, because of infection; and the third, after multiple failed acetabular revisions. The mean Harris hip score for the patients who did not have revision was 85.4 points (range, 46 to 100 points) at the time of the latest follow-up. Four patients (3%) complained of thigh pain that was not associated with another disorder. According to the criteria of Engh et al., all femoral implants were graded as stable bone-ingrown. The probability of survival of both the femoral and the acetabular component at ten years, with any revision as the end point, was 0.92 (95% confidence interval, 0.88 to 0.97). The probability of survival of the cup was 0.93 (95% confidence interval, 0.89 to 0.97), and that of the stem was 0.99 (95% confidence interval, 0.97 to 1.00). CONCLUSIONS: The results of arthroplasty with a tapered, rectangular titanium stem combined with a conical threaded cup inserted without cement were excellent at a minimum of ten years. Our data suggest that femoral stem fixation continues to be secure, while the threaded cup is prone to aseptic loosening.     

A computed tomography assessment of femoral and acetabular bone changes after total hip arthroplasty

Using computed tomography-assisted (CT) osteodensitometry, we studied the bone changes that occurred in 12 patients at 2 weeks and again at 1 year after total hip arthroplasty with insertion of a press-fit acetabular cup and an uncemented femoral tapered stem. There was a greater decrease in full bone density (BD) lateral to the femoral stem when compared to the medial side, at the proximal end of the femur this difference was significant (-22.1% versus -16.2%) ( P<0.001). At the tip of the stem cortical BD had decreased between 2.3% and 1.9% only. Proximal to the cup, the cortical BD increased by about 3.4% ( P< or =0.05), while the full BD decreased markedly by 8% ( P< or =0.001). These changes represent a response to a decrease in regional bone stress induced by the presence of the press-fit implant, and this might be considered as retro-acetabular stress shielding. No focal bone resorption was found.