Whole-mount specimens in the analysis of en bloc samples obtained from revisions of resurfacing hip implants: A report of 4 early failures

Background

Modern metal-on-metal hip resurfacing implants are being increasingly used for young and active patients, although the long-term outcome and failure mechanisms of these implants are still unknown. In this consecutive revision case series, early failures of femoral implants (at < 4 years) were studied.

Methods

3 revisions were done due to a fracture of the femoral neck and 1 due to loosening and varus position of the femoral component. Femoral heads were removed en bloc 2–46 months after the primary operation, embedded in methylmethacrylate, sectioned, stained, and analyzed as whole-mount specimens in 4 55–62-year-old patients with osteoarthritis.

Results

Histopathology was characterized by new but also partly healed trabecular microfractures, bone demineralization, cysts, metallosis, and abnormal formation of new woven bone. All samples displayed signs of notching, osteoporosis, and aseptic necrosis, which seemed to have been the main reason for the subsequent development and symptoms of the patients and revision operations of the hips.

Interpretation

Based on these early revision cases, it appears that aseptic necrosis is a common cause of early loosening of resurfacing hip implants.     

The type of surgical approach influences the risk of revision in total hip arthroplasty

Background and purpose The most common surgical approaches in total hip arthroplasty in Sweden are the posterior and the anterolateral transgluteal approach. Currently, however, there is insufficient evidence to prefer one over the other regarding risk of subsequent surgery.

Patients and methods We searched the Swedish Hip Arthroplasty Register between the years 1992 and 2009 to compare the posterior and anterolateral transgluteal approach regarding risk of revision in the 3 most common all-cemented hip prosthesis designs in Sweden. 90,662 total hip replacements met the inclusion criteria. We used Cox regression analysis for estimation of prosthesis survival and relative risk of revision due to dislocation, infection, or aseptic loosening.

Results Our results show that for the Lubinus SPII prosthesis and the Spectron EF Primary prosthesis, the anterolateral transgluteal approach gave an increased risk of revision due to aseptic loosening (relative risk (RR) = 1.3, 95% CI: 1.0–1.6 and RR = 1.6, CI: 1.0–2.5) but a reduced risk of revision due to dislocation (RR = 0.7, CI: 0.5–0.8 and RR = 0.3, CI: 0.1–0.4). For the Exeter Polished prosthesis, the surgical approach did not affect the outcome for dislocation or aseptic loosening. The surgical approach had no influence on the risk of revision due to infection in any of these designs.

Interpretation This observational study shows that the surgical approach affected the risk of revision due to aseptic loosening and dislocation for 2 of the most commonly used cemented implants in Sweden. Further studies are needed to determine whether these results are generalizable to other implants and to uncemented fixation.     

Fracture of the hip after knee arthroplasty--an unusual case with pain in the knee

Background?The long-term results of uncemented total hip arthroplasties vary widely due to differences in design, metal alloy, coating, surface structure, and porosity.

Patients and methods?We retrospectively studied 75 cementless Zweymüller SL stems in combination with Endler titanium-backed threaded cups (Z-E) in 70 patients. 35 patients were women, and the mean age at surgery was 52 (24–68) years. 16 patients died and 1 emigrated, 7 patients (of which 1 later died) subsequently underwent revision, and the remaining 47 patients with 50 original arthroplasties were followed up after a median of 16 (15–18) years.

Results?Revision of 8 hips resulted in an 18-year Kaplan-Meier estimated overall survival rate of 88% (CI: 79–96). 6 of 7 cup revisions were due to liner wear and osteolysis, and 1 was due to aseptic loosening. 2 of 3 stem revisions were due to femoral loosening and 1 was due to fracture of the neck of the stem. The clinical results were good, with a mean Harris hip score of 89 (54–100). Half of 70 hips in 65 patients had ectopic bone formation. All unrevised implants were radiographically stable, with a mean liner wear of 0.07 mm/year.

Interpretation?These long-term results demonstrate that the combination of a Zweymüller SL stem and an Endler titanium-backed screw cup is a good hip arthroplasty in young and active patients. A prefixed polyethylene liner is a drawback, necessitating exchange of the whole cup in cases with polyethylene wear.     

Improved results of primary total hip replacement

Background and purpose Over the past 20 years, several changes in treatment policy and treatment options have taken place regarding hip replacement. For this reason, we wanted to investigate the results after hip replacement in terms of revision rate, during a 21-year period among hip replacements reported to the Norwegian Arthroplasty Register.

Methods 110,882 primary total hip replacements were reported to the Norwegian Arthroplasty Register from 1987 through 2007. Risk of revision during the time periods 1993–1997, 1998–2002, and 2003–2007 was compared to that of the reference period 1987–1992. Adjusted Cox regression analyses were performed to compare the risk of revision in different time periods and extended analyses were done to investigate revision within the first postoperative year and after the first year.

Results There was an overall reduced risk of revision in the time periods 1993–1997, 1998–2002, and 2003–2007 compared to the reference period: RR = 0.81 (95% CI 0.77–0.86), 0.51 (CI 0.47–0.55), and 0.77 (CI 0.68–0.85), respectively. The improved results were due to a marked reduction in aseptic loosening of the femoral and acetabular components in all time periods and in all subgroups of prostheses. A change in the timing of revision took place, with more early revisions and fewer late revisions in the later time periods. Revision due to dislocation and infection increased over time.

Interpretation The risk of revision decreased during the study period, due to fewer cases of aseptic loosening of prosthetic components. The best results were obtained with the use of cemented prostheses. Prevention of dislocation and infection should be a major goal in the future, as revision due to these causes increased during the study period.     

Poor intermediate-term survival of the uncemented Optan anatomically adapted femoral component

Purpose — We evaluated the 5-year survival of the uncemented Optan anatomically adapted femoral stem, with revision for aseptic loosening as the endpoint.

Methods — Between January 2004 and March 2007, 432 total hip arthroplasties (THAs) were performed in 432 patients. After follow-up for a mean time of 5 years, the patients were evaluated using the WOMAC questionnaire and plain radiography. Patients who were unable to attend the follow-up visit were contacted by telephone to determine whether they had had any revision surgery of their THA

Results — Within 5 years, 39 patients (9%) had died of unrelated causes and 63 patients (15%) had been lost to follow-up. Of the remaining cohort, 224 patients (68%) had full follow-up while 88 patients (27%) were evaluated with WOMAC only and 18 patients (5%) were evaluated with radiography only. The mean WOMAC score of all evaluated patients was 21 (10–100). At 5-year follow-up, there were 26 stem revisions reported (6%), 14 hips (3%) showed aseptic loosening, and 12 hips (3%) had had a periprosthetic femoral fracture. The 5-year survival to revision for any reason was 94%. Worst-case analysis yielded a 5-year survival of 79%.

Interpretation — The 5-year survival for aseptic loosening of the Optan anatomically adapted femoral component was disappointing. Radiographic evaluation showed evidence of proximal radiolucencies and distal cortical bone hypertrophy, which we attribute to insufficient proximal bone in-growth and increased load transfer at the tip of the stem. We do not recommend the use of the Optan femoral stem.     

The Effect of Electric Current on the Healing time of Crural Fractures

Background and purpose — Uncemented stems are increasingly used in revision hip arthroplasty, but only a few studies have analyzed the outcomes of uncemented and cemented revision stems in large cohorts of patients. We compared the results of uncemented and cemented revision stems.

Patients and methods — 1,668 uncemented and 1,328 cemented revision stems used in first-time revisions due to aseptic loosening between 1999 and 2016 were identified in the Swedish Hip Arthroplasty Register. Kaplan–Meier analysis was used to investigate unadjusted implant survival with re-revision for any reason as the primary outcome. Hazard ratios (HR) for the risk of re-revision were calculated using a Cox regression model adjusted for sex, age, head size, concomitant cup revision, surgical approach at primary and at index revision surgery, and indication for primary total hip arthroplasty.

Results — Unadjusted 10-year survival was 85% (95% CI 83–87) for uncemented and 88% (CI 86–90) for cemented revision stems. The adjusted HR for re-revision of uncemented revision stems during the first year after surgery was 1.3 (CI 1.0–1.6), from the second year the HR was 1.1 (CI 0.8–1.4). Uncemented stems were most often re-revised early due to infection and dislocation, whereas cemented stems were mostly re-revised later due to aseptic loosening.

Interpretation — Both uncemented and cemented revision stems had satisfactory long-term survival but they differed in their modes of failure. Our conclusions are limited by the fact that femoral bone defect size could not be investigated within the setting of the current study.     

全髋关节置换术治疗髋臼骨折继发创伤性髋关节炎和股骨头坏死中远期疗效观察

目的 :评价全髋关节置换术治疗髋臼骨折后继发创伤性髋关节炎或股骨头坏死的中远期疗效。方法 :2000年1月至2005年12月,对33例髋臼骨折继发创伤性髋关节炎和(或)股骨头坏死患者实施全髋关节置换术。其中男21例,女12例;年龄27~69岁,平均52岁。23例骨折曾行切开复位内固定术,前侧入路5例,后侧入路12例,混合入路6例;10例行保守治疗。髋关节置换术均采用后外侧入路,术前髋臼骨折均已愈合,术中完全去除内固定5例,去除部分内固定3例,植骨20例。6例术中使用骨水泥假体,27例使用生物型假体。观察术中情况和术后并发症,比较术前Harris髋关节评分和术后10年评分,以假体松动、骨溶解或翻修为终点的生存分析显示假体10年生存率。结果:所有患者获随访,术后10年死亡1例,随访时间平均12年(10~15年),术后10年时Harris髋关节评分较术前升高。1例假体早期无菌性松动行翻修术,2例骨溶解形成合并假体无菌性松动并行翻修术治疗,单纯骨溶解无假体松动1例,术后深静脉血栓4例,假体脱位2例,切口感染和假体周围感染各1例。假体10年生存率为84.8%(28/133)。结论:全髋关节置换术治疗髋臼骨折后继发创伤性髋关节炎或股骨头坏死能明显改善患者的髋关节的功能,并有较高的假体生存率,具有良好的中远期疗效,是一种有效的治疗手段。     

Contributions of authors

Background Bone-saving hip arthroplasty techniques, which facilitate revision, are gaining importance as the number of hip replacements in younger patients increases.

Patients and methods 123 CUT femoral neck prostheses (ESKA Implants, Lübeck, Germany) were implanted in 113 patients (average age 53 years) between 1999 and 2002. After a mean follow-up of 5 (3–7) years, we determined the state of 120 prostheses; 3 patients could not be located. 97 patients with 107 prostheses, none of which had been revised, were evaluated clinically and radiographically.

Results The median Harris hip score improved from 51 points to 92 points in the unrevised hips. 13 CUT prostheses (11%) had been revised, 7 because of aseptic loosening, 3 because of persisting thigh pain, 1 because of immediate vertical migration, and 2 because of septic loosening. The 5-year survival rate of the CUT prosthesis was 89%.

Interpretation The medium-term survival with this type of femoral component is unsatisfactory, with a high rate of aseptic loosening. The surviving prostheses had a good clinical outcome.     

Revision total hip arthroplasty in juvenile chronic arthritis: 17 revisions in 11 patients followed for 4–12 years

Background Revision total hip arthroplasty (THA) in patients with juvenile chronic arthritis (JCA) is complicated by the young age of the patient, poor bone stock and small physical proportions. We report the complications and outcome of a prospective series of 17 revision THAs in Charnley class C JCA patients.

Methods 15 acetabular components and 10 femoral components were revised. 13 cementless cups, 2 reconstruction/roof rings and cemented cups, and 4 cemented and 6 cementless femoral stems were implanted. 2 proximal femoral allografts and 1 strut allograft were used. Age at revision was 32 (21–53) years. Follow-up averaged 7 (4–12) years.

Results 2 patients with cemented femoral stems developed loosening, osteolysis and fracture. Both were successfully revised to long-stem cementless implants with strut/proximal femoral allografts. 1 loose, worn cementless cup with osteolysis was revised. 1 patient with a peri-operative infection and late acetabular fracture had a loose, non-revised cementless cup. 1 case of sciatic nerve palsy occurred after revision using a reconstruction ring. 1 late infection necessitated resection arthroplasty. Harris hip scores improved from 53 (34–85) to 76 (47–96).

Interpretation Revision THA in JCA has a substantial complication rate, even in experienced hands. The problem of obtaining long-term stable fixation, osteolysis, and replenishment of lost bone stock are major difficulties.     

N-acetylcysteine attenuates lung injury in a rodent model of fracture

Background?The role of growth factors in prosthesis loosening is unclear. We evaluated the levels of plate-let-derived growth factor BB (PDGF-BB), transforming growth factors β1 (TGF-β1) and β2 (TGF-β2), both before and after activation, in patients with aseptic loosening of their hip prosthesis.

Patients and methods?26 patients with loosened hip implants were compared with 21 patients who had stable hip prostheses, and 28 patients undergoing primary hip replacement. The plasma levels of the growth factors were analyzed by enzyme immunoassay. TGF-β1 and TGF-β2 were determined both before and after activation.

Results?Patients with aseptic loosening had significantly lower PDGF-BB levels than patients undergoing primary hip replacement, and significantly lower TGF-β2 levels than patients with a stable implant. Patients with stable prostheses had significantly higher TGF-β1 and TGF-β2 levels than patients undergoing primary hip replacement.

Interpretation?It is possible that the prosthetic implant itself causes a local increase in PDGF-BB, TGF-β1 and TGF-β2, released by osteoblasts and other cells in the microenvironment. The plasma PDGF-BB measured does not correspond to local release, which is probably due to local consumption or degradation. The consumption of PDGF-BB is low in stable implants, and TGF-β1 and TGF-β2 levels increase during bone formation. In loosening, PDGF-BB consumption is higher and causes a significant reduction in plasma levels as compared to presurgery. The formation of poor-quality bone may be related to the scarce increase in TGF-β1 and TGF-β2. In conclusion, compared with patients with a stable implant, a reduction in bone-forming growth factors appears to occur in individuals with aseptic loosening.     

Reconstruction of the rotation center of the hip after oblong cups in revision total hip arthroplasty

Background

The preoperative bone defect and the reconstruction of the center of rotation of the hip are critical in acetabular revision surgery. Uncemented oblong cups are employed in order to manage these issues. We analyzed the clinical results and rates of revision of two different uncemented oblong cups, the reconstruction of the center of rotation of the hip, as well as the rate of radiological loosening and possible risk factors.

Materials and methods

Forty-five patients (46 hips) underwent acetabular revision surgery using two different uncemented oblong cups. We assessed the clinical results and the survival rate for revision and aseptic loosening. Intraoperative bone loss was classified according to Paprosky, and acetabular reconstruction was assessed according to Ranawat. The mean follow-up was 7.2 years (range 4–11 years).

Results

There were four re-revisions (three due to aseptic loosening); the survival rate for re-revision due to aseptic loosening was 60.1 % at seven years. The mean distance between the center of the femoral head prosthesis and the approximate center of the femoral head improved from 21.5 to 10.2 mm. Thirteen cups showed radiological loosening; the survival rate for radiological loosening at seven years was 40.54 %. A smaller postoperative horizontal distance was correlated with cup loosening.

Conclusions

Although optimal acetabular reconstruction can be achieved by using oblong uncemented cups in revision hip surgery, the clinical and radiological results are not encouraging. Excessive medialization of the cup may increase the rate of loosening.     

Total hip arthroplasty for rheumatoid arthritis in younger patients: 2,557 replacements in the Finnish Arthroplasty Register followed for 0–24 years

Background?The results of total hip arthroplasty (THA) in young patients with rheumatoid arthritis (RA) have been reported in only a few studies. On a nationwide level, the outcome of THA in these patients is unknown. We evaluated the population-based survival of THA in patients under 55 years of age with RA and factors affecting the survival.

Patients?Between 1980 and 2003, 2,557 primary THAs performed for RA in patients less than 55 years of age were reported to the Finnish Arthroplasty Register.

Results?Proximally circumferentially porous-coated uncemented stems had a 15-year survival rate of 89% (95% CI 83–94) with aseptic loosening as endpoint. The risk of stem revision due to aseptic loosening was higher with cemented stems than with proximally porouscoated uncemented stems implanted during the same period (RR 2.4; p < 0.001). In contrast, Cox regression analysis showed that the risk of cup revision was significantly higher for all uncemented cup concepts than for all-polyethylene cemented cups with any cup revision as endpoint. There were no significant differences in survival between the THR concepts.

Interpretations?Uncemented proximally circumferentially porous-coated stems and cemented all-poly-ethylene cups are currently the implants of choice for young patients with RA.     

Middle term results of tantalum acetabular cups in total hip arthroplasty following pelvic irradiation

ObjectivesThe aim of this study was to evaluate the middle term cup survival, assess the functional implementation and the radiographic evolution of tantalum acetabular cups implanted on patients with a history of pelvic radiotherapy.MethodsFrom 2005 to 2013, we performed 12 THA replacements (4 males 8 females; mean age: 46.6 years (range 25–75)) on irradiated bone with Trabecular metal acetabular cups, 8 primary implants and 4 revision implants. The mean radiation dose delivered was 5500 cGy (range 3000 cGy–13,600 cGy). The mean follow-up was 68 months, ranging from 38 to 136. Postoperative follow-up time was assessed at 1, 3, 6 and 12 months, then annually. Double projection radiographs were requested at each control. Radiographic signs of loosening were investigated by X-rays looking for radiolucent lines. We used the Harris hip score for the clinical and functional evaluation.ResultsTo now none of the 12 patients in the series needed any revision surgery for aseptic loosening. In the revision group one patient have been revised for septic loosening, two patients have been treated by conservative procedure for hip dislocation. Post-operative Harris hip score improved from an average of 46 points to 85.3 points. At last follow-up we found only in one case radiographic signs of progressive lucent line, without clinical sign of failure.ConclusionIn a clinical setting, tantalum cup seems to provide a good stability due to the integration of the trabecular metal to the underline cancellous bone. The reported results, in agreement with literature data, propose the use of tantalum cups in irradiated bone.Level of evidenceLevel IV, therapeutic study.     

Results of 3,668 primary total hip replacements for primary osteoarthritis in patients under the age of 55 years

Background and purpose In a previous study based on the Finnish Arthroplasty Register, the survival of cementless stems was better than that of cemented stems in younger patients. However, the survival of cementless cups was poor due to osteolysis. In the present study, we analyzed population-based survival rates of the cemented and cementless total hip replacements in patients under the age of 55 years with primary osteoarthritis in Finland.

Patients and methods 3,668 implants fulfilled our inclusion criteria. The previous data included years 1980–2001, whereas the current study includes years 1987–2006. The implants were classified in 3 groups: (1) implants with a cementless, straight, proximally circumferentially porous-coated stem and a porous-coated press-fit cup (cementless group 1); (2) implants with a cementless, anatomic, proximally circumferentially porous-coated stem, with or without hydroxyapatite, and a porous-coated press-fit cup with or without hydroxyapatite (cementless group 2); and (3) a cemented stem combined with a cemented all-polyethylene cup (the cemented group). Analyses were performed separately for 2 time periods: those operated 1987–1996 and those operated 1997–2006.

Results The 15-year survival for any reason of cementless total hip replacement (THR) group 1 operated on 1987–1996 (62%; 95% CI: 57–67) and cementless group 2 (58%; CI: 52–66) operated on during the same time period was worse than that of cemented THRs (71%; CI: 62–80), although the difference was not statistically significant. The revision risk for aseptic loosening of cementless stem group 1 operated on 1987–1996 (0.49; CI: 0.32–0.74) was lower than that for aseptic loosening of cemented stems (p = 0.001).

Interpretation Excessive wear of the polyethylene liner resulted in numerous revisions of modular cementless cups. The outcomes of total hip arthroplasty appear to have been relatively unsatisfactory for younger patients in Finland.     

Limited range of motion of hip resurfacing arthroplasty due to unfavorable ratio of prosthetic head size and femoral neck diameter

Background and purpose?Hip resurfacing arthroplasty is being used more and more frequently. The small ratio in size between the resurfaced femoral head and the relatively thick femoral neck raises the question of whether the range of motion is sufficient, particularly with regard to the high mobility required by younger patients. We analyzed motion in a CAD model.

Methods?Three-dimensional CAD models of the natural hip were created from CT scans and 8 designs of hip resurfacing prostheses (head diameter between 42 mm and 54 mm combined with a hemispherical cup) were implanted in a virtual sense. We simulated 3 different leg positions and the range of motion was evaluated, considering five different implant positions.

Results?The range of motion of the hip resurfacing designs analyzed was far below the range of motion of stemmed total hip prostheses. None of the resurfacing prostheses provided flexion movements of 90° without impingement. The average range of motion of hip resurfacing arthroplasty was 31–48° below the range of motion of a stemmed total hip replacement with 32-mm head diameter.

Interpretation?The range of motion of the hip resurfacing designs examined was substantially less than that of a conventional total hip prosthesis. Since impingement of the femoral neck on the acetabular component increases the risk of neck fractures, of dislocation and of subsequent implant loosening, the design and position of the implant should be considered before using hip resurfacing arthroplasty as a standard treatment for younger patients.     

Long-term outcome of cemented total hip arthroplasty with the Charnley-type femoral stem made of titanium alloy

BackgroundTotal hip arthroplasty is a successful treatment for hip diseases including osteoarthritis, osteonecrosis of the femoral head, and rheumatoid arthritis. Various designs of cemented femoral stems made of stainless steel and titanium alloy have been used. Among them, Charnley-type femoral stems made of stainless steel have often been reported to have good long-term outcome. However, the long-term outcome of the Charnley-type femoral stem made of Ti alloy is yet to be reported. We conducted a retrospective study to assess the long-term outcome of cemented primary total hip arthroplasty with the Charnley-type femoral stem made of Ti alloy.MethodsBetween October 1988 and February 1997, 341 cemented primary total hip arthroplasties with the Charnley-type femoral stem made of Ti alloy were consecutively performed in our hospital. Among these, 164 patients (211 hips) who underwent this procedure were followed up for more than 12 years, and the surgical hips were analysed clinically and radiologically. The mean follow-up period was 20.6 years. Kaplan–Meier survival analyses were performed to assess femoral component survival. Factors affecting stem revision for aseptic loosening were also investigated using log-rank tests.ResultsIn the functional assessment, the preoperative Japanese Orthopaedic Association score significantly improved from 47.2 points preoperatively to 79.0 points at the final follow-up. Eventually, 33 femoral stems were revised, of which 12 were revised for aseptic loosening. In the Kaplan–Meier survival analysis, the 20-year survival rates with stem revision for aseptic loosening and radiological stem loosening at the end points were 95.9% and 97.1%, respectively. Original diagnosis (non-osteoarthritis) was the only significant factor for aseptic loosening of the femoral stem.ConclusionsCemented primary total hip arthroplasty with the Charnley-type femoral stem made of Ti alloy showed excellent outcomes for more than 20 years.     

Morselized bone grafting in revision arthroplasty of the knee: A retrospective analysis of 34 reconstructions after 2–9 years

Background and purpose?Loosening of a total knee replacement may lead to loss of bone, requiring biological reconstruction at revision arthroplasty. Good results have been reported from revision arthroplasty of the hip using impaction bone grafting. We report our results of revision total knee arthroplasty using the same technique.

Patients and methods?We retrospectively analyzed 30 patients (involving 34 knees) with a mean age of 63 (34–81) years who, between 1994 and 2002, underwent revision arthroplasty of the knee using hinge or rotational knee prostheses (Link) and impaction bone grafting. The average follow-up was 4 (2–9) years and included a questionnaire, a clinical examination, and standardized radiographs.

Results?25 patients were satisfied with their results. 10 patients reported no impairment in their activities of daily living attributed to their operation and did not need any walking support. In 5 patients, there were no clear radiographic signs of incorporation of the graft but that did not compromise the outcome. 5 other patients had complications due to aseptic loosening of their prostheses with radiographic failure of the graft, leading to a periprosthetic fracture in 2 cases.

Interpretation?Our results with impaction bone grafting in knee revision arthroplasty appear to be similar to those obtained by the same technique in revision hip surgery.     

Total hip replacement after femoral neck fractures in elderly patients : Results of 8,577 fractures reported to the Norwegian Arthroplasty Register

Background?A total hip arthroplasty (THA) is often used as treatment for failed osteosynthesis of femoral neck fractures and is now also used for acute femoral neck fractures. To investigate the results of THA after femoral neck fractures, we used data from the Norwegian Arthroplasty Register (NAR).

Patients and methods?The results of primary total hip replacements in patients with acute femoral neck fractures (n = 487) and sequelae after femoral neck fractures (n = 8,090) were compared to those of total hip replacements in patients with osteoarthrosis (OA) (n = 55,109). The hips were followed for 0–18 years. The Cox multiple regression model was used to construct adjusted survival curves and to adjust for differences in sex, age, and type of cement among the diagnostic groups. Separate analyses were done on the subgroups of patients who were operated with Charnley prostheses.

Results?The survival rate of the implants after 5 years was 95% for the patients with acute fractures, 96% for the patients with sequelae after fracture, and 97% for the OA patients. With adjustment for age, sex, and type of cement, the patients with acute fractures had an increased risk of revision compared to the OA patients (RR 1.6, 95% CI: 1.0–2.6; p = 0.05) and the sequelae patients had an increased risk of revision (RR 1.3, 95% CI: 1.2–1.5; p < 0.001). Sequelae hips had higher risk of revision due to dislocation (RR 2.0, 95% CI: 1.6–2.4; p < 0.001) and periprosthetic fracture (RR 2.2, 95% CI: 1.5–3.3; p < 0.001), and lower risk of revision due to loosening of the acetabular component (RR 0.72, 95% CI; 0.57–0.93; p = 0.01) compared to the OA patients. The increased risk of revision was most apparent for the first 6 months after primary operation.

Interpretation?THA in fracture patients showed good results, but there was an increased risk of early dislocations and periprosthetic fractures compared to OA patients.     

Der Oberflächenersatz am Hüftgelenk

Resurfacing arthroplasty is regarded as an attractive method, especially for the young patient who needs a hip replacement. However, the high expectations regarding this new technique in THR must first be met. Earlier experiences with similar forms of surface replacement have led to high revision rates with early aseptic wear induced component loosening and neck fractures. Technical progresses in production techniques for metal-on-metal articulations with minimized wear have enabled the introduction of new surface replacements for the hip joint. Long-term results of these resurfacing arthroplasties are still due. Femoral neck fractures and femoro-acetabular impingement are possible early complications which require revision. The implantation of these systems requires a high degree of operative skill and experience on the part of the surgeon. Approach dependent trauma to the musculature and endangering of the blood supply to the femoral head is balanced with the positive effect of the preservation of femoral bone stock and better options in case of revision. Whether the younger patient with a higher activity profile and an increased chance of implant loosening actually profits from the resurfacing arthroplasty will be determined in the future.     

Prosthetic overhang is the most effective way to prevent scapular conflict in a reverse total shoulder prosthesis

Background and purpose?Controversies still exist about whether there is any effect of operative approach on survival of hip prostheses. We compared long-term survival of primary total hip arthroplasties in a welldefined study population from a national prospective population-based registry with regard to the three most commonly used surgical approaches.

Methods?We assessed prosthesis survival according to surgical approach (the lateral with or without trochanteric osteotomy, and the posterolateral) for 19,304 Charnley and 6,002 Exeter total hip arthroplasties performed from 1987 to 2004.

Results?For Charnley total hip arthroplasties, lateral approach with trochanteric osteotomy had a lower probability of revision than lateral approach without trochanteric osteotomy (RR = 0.6, 95% CI: 0.5–0.8). The lower revision rate was due to fewer revisions for aseptic loosening and dislocation. The differences had declined in the latest time period (1995–2004). We observed no differences between lateral approach without trochanteric osteotomy and posterolateral approach, except that there were more revisions due to dislocation in the posterolateral approach group (RR = 1.9, 95%CI: 1.1–3.2). No statistically significant differences were observed for Exeter total hip arthroplasties.

Interpretation?For Charnley prostheses, the lateral approach with trochanteric osteotomy gave a reduced revision risk compared to the other approaches, which was due to fewer revisions for dislocation, and in the first time period also fewer revisions due to aseptic loosening.