Loosening Of Acetabular Component Research Articles

Does Acetabular Inclination Angle Affect Survivorship of Alumina-ceramic Articulations?

Reports in the literature have linked high acetabular inclination angles to increased wear of ceramic-on-ceramic bearings. However, many of these studies were only conducted in vitro and did not address the clinical relevance of such findings. We therefore determined: (1) whether the cup inclination angle influences survival or function in patients with ceramic-on-ceramic implants; (2) the incidence of radiolucencies, osteolysis, and subsidence of ceramic-on-ceramic implants; and (3) whether the survival rate higher for ceramic-on-ceramic THAs than for conventional metal-on-polyethylene THAs. We retrospectively reviewed 537 THAs performed in 512 prospectively followed patients having THA between October 1996 and October 2000. Eleven patients (12 hips) were lost to followup before 2 years, leaving 501 patients (525 THAs); of these, 421 were alumina ceramic-on-ceramic articulations and 104 cobalt-chromium-on-polyethylene. The mean age was 54 years. We determined acetabular cup inclination angles, Harris hip scores, Health-Status-Questionnaire-12 scores, and presence and location of any radiolucencies, osteolysis, or radiographic subsidence. We compared survival using the Kaplan-Meier method. The minimum followup was 24 months (mean, 59 months; range, 24-120 months). Twenty-two of the 424 THAs (4.2%) were revised. We observed no difference in clinical or radiographic outcomes with respect to cup inclination angles. Radiographically, two loose acetabular components and two femoral components had subsided. The 5-year survival rate was slightly higher for ceramic-on-ceramic bearings (98%) than for metal-on-polyethylene (92%). Although there may be a link between acetabular inclination angles and wear rates as reported by some authors, we found no differences in patient function or radiographic survivorship using alumina-on-alumina articulations.

Revisions of Extensive Acetabular Defects with Impaction Grafting and a Cement Cup

BackgroundLoosening of acetabular components often leads to bony defects. Management of extensive acetabular bone loss in hip revision arthroplasty can be a tremendous challenge.Questions/purposesWe asked whether a reconstruction with impacted bone grafts will provide a durable and pain-free function in extensive acetabular defects. We specifically determined the (1) survival rates with the end point of revision for any reason, aseptic revision, and radiographic loosening; (2) visual analog scale (VAS) pain score, Harris hip score (HHS), and the Oxford Hip Questionnaire score (OHQS); (3) number of repeat revisions; (4) complications; and (5) radiographic loosening, wear, and radiolucencies.Patients and MethodsWe retrospectively followed 25 patients (27 hips) with extensive acetabular defects. No patient was lost to followup. Two patients died during followup. Minimum followup was 3 years (mean, 8.8 years; range, 3–14.1 years).ResultsThree patients (three hips) underwent repeat revision surgery and another two patients (two hips) had radiographically loose hips. The 10-year survival rate was 88% (95% confidence interval, 74.2%–100%) with the end point acetabular revision for any reason and 95% (95% confidence interval, 86.0%–100%) with the end point acetabular revision for aseptic loosening. The mean HHSs were 55 points before surgery and 72 points postoperatively.ConclusionsAcetabular reconstruction with impaction bone grafting and a cemented cup is a reliable technique with a 10-year survival rate of 88% in patients with extensive acetabular deficiencies.Level of EvidenceLevel IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.

Correlation of Technetium-99m Scintigraphy, Progressive Acetabular Osteolysis and Acetabular Component Loosening in Total Hip Arthroplasty

In total hip arthroplasty (THA) Technetium scintigraphy can help to diagnose a loose implant by detecting elevated osteoblastic activity. It has been used for timing the revision of cemented implants. In uncemented cups progressive radiological acetabular osteolysis can be present before loosening accurs, but it is probably unwise to await cup loosening before embarking on revision. We explored the possible relationship between such osteolysis and positive findings on technetium scintigraphy, to see if the technique could predict the need for revision. Between 1990 and 1996 500 hydroxyapatite-coated hip prostheses were implanted (follow-up range: 9-15 years), and technetium scintigraphy and plain radiography were performed annually postoperatively. 32 cups were revised for progressive acetabular osteolysis. We compared the introperative findings at revision with the pre-operative scintigraphic and radiographic results. The sensitivity and specificity for diagnosing progressive acetabular osteolysis by technetium scintigraphy were 34% and 0% respectively. The sensitivity and specificity of the technique for detecting loosening were 38% and 73% respectively. The sensitivity and specificity of technetium scintigraphy for detection of a either loosening or progressive acetabular osteolysis are worse than reported for plain radiography. Despite negative scintigraphy, there may be progressive bone loss at a critical level. Scintigraphy has no additional value to plain radiography as a reliable indicator for timing cup revision in the process of progressive acetabular osteolysis.

Failed Metal-on-Metal Hip Arthroplasties: A Spectrum of Clinical Presentations and Operative Findings

A number of recent reports have described novel failure mechanisms of metal-on-metal bearings in total and resurfacing hip arthroplasty. Hip arthroplasties with metal-on-metal articulations are also subject to the traditional methods of failure seen with different bearing couples. There is currently little information in the literature to help guide timely clinical evaluation and management of these patients. We therefore describe the (1) clinical presentations; (2) reasons for failure; (3) operative findings; and (4) histologic findings in patients with failed metal-on-metal hip arthroplasties. We retrospectively identified all 37 patients (37 hips) with metal on metal total hip or resurfacing arthroplasties who underwent revision over the past 3 years at our institution. Relevant clinical, radiographic, laboratory, intraoperative, and histopathologic findings were analyzed for all patients. Of the 37 patients, 10 were revised for presumed hypersensitivity specific to the metal-on-metal articulation. This group included eight patients with tissue histology confirming chronic inflammation with lymphocytic infiltration, eight with aseptic loosening of a monoblock screwless uncemented acetabular component, two with iliopsoas impingement associated with a large-diameter femoral head, and three with femoral neck fracture after resurfacing arthroplasty; the remainder of the patients were revised for infection, instability, component malposition, and periprosthetic fracture. Increased awareness of the modes of failure will bring to light the potential complications particular to metal-on-metal articulations while placing these complications into the context of failures associated with all hip arthroplasties. This novel clinical information should be valuable for the practicing surgeon faced with this patient population. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Revision hip replacement for recurrent Hydatid disease of the pelvis: a case report and review of the literature

A case of a large recurrent hydatid cyst involving the right ilium and right hip treated with excision of the cyst, Total hip replacement and revision of the acetabular component with a Tripolar articulation for cyst recurrence and acetabular component loosening is presented along with a review of the relevant literature. To our knowledge there is no reported case of Total Hip replacement and revision for hydatid disease involving the bony pelvis.

Augmentation of Bone Growth onto the Acetabular Cup Surface Using Bone Marrow Stromal Cells in Total Hip Replacement Surgery

Aseptic loosening of acetabular components in total hip arthroplasty is the major cause of implant failure. Our hypothesis was that spraying autologous bone marrow-derived stromal cells (BMSCs) in fibrin glue onto the surface of hydroxyapatite-coated uncemented acetabular components would increase bone formation and contact in a caprine model. Ten million BMSCs were sprayed onto the acetabular cup at the time of surgery. Animals in the control group received fibrin glue only. Ground reaction force measurements were taken preoperatively and at 6 and 12 weeks postsurgery. After retrieval at 12 weeks new bone formation, bone-implant contact and fibrous tissue thickness adjacent to the cup were quantified. Viability and proliferation assays showed that the majority of the BMSCs survived spraying in fibrin glue at pressures of up to 1.5 atm. New bone growth adjacent to the bone implant interface in the BMSC-treated group (71.42 +/- 8.97%) was 30% greater than in control (54.22 +/- 16.56%) although this difference was not statistically significant. However, significantly increased new bone formation was measured at the periphery of the cup (zone 5) in the BMSC-treated group (71.97 +/- 10.91%) when compared with control (23.85 +/- 15.13%, p = 0.028). Bone-implant contact was significantly greater in the BMSC-treated group (20.03 +/- 4.64%) (control: 13.71 +/- 8.32%, p = 0.027); correspondingly, the average thickness of the fibrous tissue membrane where present was significantly reduced at the periphery of the cups in the BMSC-treated group (327.49 +/- 20.38 mum) when compared with control (887.21 +/- 158.89 mum) (p = 0.02). This study has clinical applications as greater bone contact at the cup surface will improve fixation and may decrease longer-term aseptic loosening by preventing wear debris-induced bone loss at the implant interface.

Short-term results of total hip replacements performed by visiting surgeons at an NHS treatment centre

Between December 2004 and June 2006, 136 patients (156 total hip replacements), were sent from the waiting list of the Cardiff Vale NHS Trust to the NHS Treatment Centre, Weston-super-Mare, in an attempt to reduce the waiting time for total hip replacement. Because of concerns about their outcome, each patient was contacted and invited to attend a review appointment with a consultant specialising in hip and revision hip replacement. A total of 98 patients (113 hips) were reviewed after a mean of 23 months (11 to 30). There were 104 cemented hips, seven hybrid and two cementless. An acetabular inclination of > 55 degrees was seen in 18 (16%). Radiolucent lines around the acetabular component were seen in 76 (67%). The femoral component was in more than 4 degrees of varus in 47 (42%). The medial floor had been breached in 13 (12%) and there was a leg-length discrepancy of more than 1 cm in ten (9%). There were three dislocations, one femoral fracture, one pulmonary embolus, one deep infection and two superficial wound infections. To date, 13% (15 hips) have been revised and a further 4% (five hips) await revision, mostly for a painful loose acetabular component. The revision rate far exceeds the 0.5% five-year failure rate reported in the Swedish Registry for the components used. This initiative and the consequent need for correction of the problems created, has significantly increased the workload of our unit.

The principle of low frictional torque in the Charnley total hip replacement

The design of the Charnley total hip replacement follows the principle of low frictional torque. It is based on the largest possible difference between the radius of the femoral head and that of the outer aspect of the acetabular component. The aim is to protect the bone-cement interface by movement taking place at the smaller radius, the articulation. This is achieved in clinical practice by a 22.225 mm diameter head articulating with a 40 mm or 43 mm diameter acetabular component of ultra-high molecular weight polyethylene. We compared the incidence of aseptic loosening of acetabular components with an outer diameter of 40 mm and 43 mm at comparable depths of penetration with a mean follow-up of 17 years (1 to 40). In cases with no measurable wear none of the acetabular components were loose. With increasing acetabular penetration there was an increased incidence of aseptic loosening which reflected the difference in the external radii, with 1.5% at 1 mm, 8.8% at 2 mm, 9.7% at 3 mm and 9.6% at 4 mm of penetration in favour of the larger 43 mm acetabular component. Our findings support the Charnley principle of low frictional torque. The level of the benefit is in keeping with the predicted values.

Long-Term Survival and Reason for Revision of Wagner Resurfacing Hip Arthroplasty

The long-term survival of 270 Wagner resurfacing hip arthroplasties was determined. Two patients were lost to follow-up. Eleven hips remained unrevised at 15 to 22 years. Survival at 5, 10, and 16 years was 74%, 35%, and 17%, respectively. Survival in patients older than 55 years was better after 5 years than that for patients 55 years or younger ( P = .0067). Femoral neck fracture occurred in 2% of the total cohort. Femoral component failure was an early and midterm complication. Acetabular component loosening was the most common reason for revision. The proportion of cases revised for acetabular component failure increased with time. These long-term data in this large series provide important historical results against which the relative benefits of contemporary designs may be evaluated.

Friction Reduction in Metal on Metal Hip Joint

In the world, approximately 800,000 total hip replacements are implanted, while, at least 50,000 hip replacements are performed in the United Kingdom each year. Orthopaedic surgeons have traditionally delayed joint replacement surgery in patients younger than 60 due to its limited survivorship time and biological effect inside the human body. The highest percentage (71%) hip joint failure was caused by aseptic loosening of the femoral and acetabular components and the war rate and debris are the accepted causes of that aseptic loosening. The wear particles, either ion or stable form, can react with proteins and change the pH value of albumin solutions inside the human body, causing damage to the DNA resulting in genotoxicity. There has been a great deal of research into the materials, dimension of the prosthesis, surface roughness, and lubrication effect by surface coating. But it is very rare to apply surface texture technique to a metallic prosthesis bearing surface although it has proven very successful in many engineering applications including automobile industry due to secondary lubrication effect and hydrodynamic effect. A TE 77 high frequency friction simulator has been used for the experiment where specimens were manufactured with 50 mm diameters and 50μm clearance. A dynamic loading was applied synchronized with Hip CD 98 while the temperature was controlled at 37°C. The output data including friction coefficient, friction force and contact pot were recorded in connected computer via COMPEND 2000 software. The surfaces were inspected after and before test under scanning electronic microscopy. The plateau honed surfaces were produced on the moving specimens with controlled load, speed and various grade of emery paper using a specially designed tool. The friction coefficient was recorded 0.035 for the honing surface which was made by 30 kg laod and 60 emery paper, 0.04 for the honing surface profile made by 30 kg load and 150 emery paper and 0.06 for plane surface after one million cycles. The rest of surfaces profiled surface were broken down before one million cycles. That made a conclusion that plateau honing surface made with 30 kg load and 60 emery paper was best surface texture profile (45° honed angle, 40±10μm width and 35±10μm depth honing) for the metal on metal hip prosthesis. The comparison experiment was continue for plane surface and plateau honing surface of 60 emery paper and 30 kg load up to one and half millions cycles. It was found that the friction coefficient (0.03) was further reduced 0.005 after one and half million cycles for plateau honing surface but it was increased nearly double (0.065) for plane surface. The static friction coefficient was also reduced 38% in case of that plateau honing surface. The contact pot profile which is an indicator of fluid film thickness was noticed higher in plateau honing surface. This was evidence that the lubrication distribution was better in plateau honed surface which should provide longer life of joint, reduce wear and improves acceptability of metal on metal hip joints.

Open Reduction Internal Fixation and Primary Total Hip Arthroplasty of Selected Acetabular Fractures

The purpose of our study was to analyze the outcomes of patients treated with combined open reduction internal fixation (ORIF) and primary total hip arthroplasty (THA) for selected cases of acetabular fractures. Retrospective case series. University Medical Center. Four hundred twenty patients underwent ORIF for displaced acetabular fractures at our institution. Twenty-one of these patients underwent ORIF and primary THA. All surgeries were performed under the direct supervision of a fellowship-trained orthopaedic trauma surgeon and a fellowship trained adult reconstructive surgeon who acted as a cosurgeon. At the time of review, 18 patients met the 1-year follow-up requirement and formed the study cohort. Mean patient age was 71 years (range 55-86 years). There was 1 transverse fracture, 1 anterior column posterior hemitransverse and 1 both-column fracture. There were 15 posterior wall fractures. Of the 15 posterior wall fractures, 1 was associated with posterior column fracture, 1 with dome fracture, 2 with transverse fractures, and 9 with femoral head impaction fracture. There were 2 patients with isolated posterior wall fractures. Clinical outcomes were analyzed using Harris hip score. Radiographs were analyzed for implant migration and loosening around the implant. Of the 18 patients in the study, 14 patients were followed for more than 2 years (average 3.9 years, range 1-10.1 years). All but 1 patient healed successfully. One patient required revision and placement of a constrained prosthesis due to failure of acetabular component, 3 weeks post-index procedure. Harris hip score ranged from 78 to 99 with a mean of 88. The radiographs showed an average medial displacement of 1.2 mm (range 0-3 mm) and an average vertical displacement of 1.3 mm (range 0-4 mm). There was no radiographic evidence of acetabular component loosening, but loosening was evident on 1 uncemented femoral stem. Treatment of acetabular fractures remains challenging particularly in the presence of severe osteopenia, comminution, or associated femoral head fracture. In appropriately selected patients, ORIF and primary THA provide an acceptable treatment option.

Initial American Experience with Hip Resurfacing Following FDA Approval

In May 2006, the US Food and Drug Administration approved the first metal-on-metal total hip resurfacing. Surgeons wanting to implant this device were required to undergo formal industry-sponsored training before performing their first case and a technical specialist attended their initial 10 cases. Safety surveys were completed on the first 537 cases performed and included patient age, gender, diagnosis, and occurrence of any unexpected events perioperatively or postoperatively. Intraoperative data were available for all 537 cases (100%), hospital discharge and six-week data were available for 524 cases (97.6%), three-month data were available for 523 cases (97.4%), six-month data were available for 509 cases (94.3%) and one-year data were available for 449 cases (83.6%); the mean followup was 10.4 months. We documented adverse events in 40 (32 major, 8 minor) of the 537 cases including nine nerve injuries and eight dislocations. There were 14 component revisions (3.1%) [corrected] within the first year, including 10 for femoral neck fracture, two for dislocations, and two for acetabular component loosening. Complications were frequently seen among patients older than 55 years of age and in women, emphasizing the importance of appropriate patient selection for the procedure. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Is Patient Selection Important for Hip Resurfacing?

The optimal implant option for hip arthroplasty in the young, active patient remains controversial. There has been renewed interest for metal-on-metal hip resurfacing due to improved design and manufacturing of implants, better materials, enhanced implant fixation, theoretical advantages over conventional total hip arthroplasty, and recent Food and Drug Administration approval of two devices. Recent studies indicate satisfactory short- and midterm clinical results (1- to 10-year followup) with low complication rates, but there is a learning curve associated with this procedure, a more extensive surgical approach is necessary, and long-term results have yet to be determined. Proper patient selection may help avoid complications and improve patient outcomes. Patient selection criteria in the literature appear based predominantly on theoretical considerations without any consensus on stratifying patient risk. The most commonly reported complications encountered with hip resurfacing include femoral neck fracture, acetabular component loosening, metal hypersensitivity, dislocation, and nerve injury. At the time of clinical evaluation, patient age; gender; diagnosis; bone density, quality, and morphology; activity level; leg lengths; renal function; and metal hypersensitivity are important factors when considering a patient for hip resurfacing. Based on our review, we believe the best candidates for hip resurfacing are men under age 65 with osteoarthritis and relatively normal bony morphology. Level V, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

The Role of Arthroscopy in Evaluation of Painful Hip Arthroplasty

Unexplained pain after hip arthroplasty is frustrating for patients and surgeons. We describe the use of hip arthroscopy in management of the painful hip arthroplasty, critically evaluate the outcomes of these patients, and refine indications for hip arthroscopy in this setting. We retrospectively reviewed 14 patients (16 hips) who underwent hip arthroscopy after joint replacement. One patient had suspected septic arthritis despite negative aspiration and one had known septic arthritis but was not a candidate for open arthrotomy; two had intraarticular migration of hardware. The remaining 10 patients (11 hips) had persistent pain despite negative diagnostic studies. The two patients (two hips) with infection were successfully treated with arthroscopic lavage and débridement plus intravenous antibiotics. Intraarticular metal fragments and a loose acetabular screw were successfully removed in two patients (three hips). Findings in the remaining 11 hips included a loose acetabular component (one); corrosion at the head-neck junction of a metal-on-metal articulation (one); soft tissue-scar impingement at the head/cup interface (four); synovitis with associated scar tissue (four); and capsular scarring with adhesions (one). Arthroscopy represented a successful treatment or directly led to a successful treatment in 12 of 16 hips. We observed no complications as a result of the arthroscopy. Arthroscopy may be of value in selected patients undergoing hip arthroplasty with unexplained pain after an inconclusive standard workup. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Survie à 16,5 ans de recul moyen de la cupule, double mobilité, non scellée de Bousquet dans l’arthroplastie totale de hanche. Série historique de 437 hanches

The purpose of this study was to evaluate the long-term results of a retrospective series of primary arthroplasty with a cementless dual mobility socket and a cemented Charnley type femoral component. This study included 437 hip replacements performed between 1984 and 1990, in 388 patients. The Bousquet's acetabular component, an original concept of cementless dual mobility socket has been used, associated with a cemented Charnley type femoral component. A clinical and radiologic analysis was done. The outcome is known for 345 hips (79%): 164 alive without revision at a mean of 16,5 years follow-up, 137 died without revision and 44 failures. Ninety-two (21%) were lost at follow-up. According to Kaplan-Meier analysis, the 5-year survival rate, was 84,4%+/-4,5 with revision for any reason (infection, dislocation, osteolysis...) for end point. Revision, for aseptic loosening of femoral or acetabular component, was performed in 30 hips (6,8%). Five dislocations occurred and were revised: two early related to technical errors and three after 10 years or more of follow-up. The young age of the patients at the time of the index surgery was correlated with higher rate of aseptic loosening. The prevalence of revision for dislocation is very low in our series. This concept does not avoid wear, osteolysis and aseptic loosening, especially in young active patients but the long-term stability is confirmed. We recommend this type of prosthesis for patients over 70 years and for younger patients with high risk of dislocation Q.

Eleven Years of Experience With Metal-on-Metal Hybrid Hip Resurfacing: A Review of 1000 Conserve Plus

Hip resurfacing is currently the fastest growing hip procedure worldwide. We reviewed 1000 hips in 838 patients who received a Conserve Plus (Wright Medical Technology, Inc., Arlington, Tenn) resurfacing at a single institution. The mean age of the patients was 50.0 years with 74.7% male. The hips were resurfaced irrespective of femoral defect size or etiology. The mean follow-up was 5.6 years (range, 1.1-11.0 years). All clinical scores improved significantly ( P < .05). There was no acetabular component loosening. Ten were converted to total hip arthroplasty for femoral neck fracture, 20 for femoral loosening, 2 for sepsis, and 1 for recurrent subluxations. The 5-year survivorship was 95.2% with no failures in hips implanted since 2002. Short-term failures can be prevented. First-generation surgical technique and a low body mass index were the most important risk factors for the procedure. Improvements in bone preparation significantly increased prosthetic survival in hips with risk factors for failure.

Metal-on-Metal Hip Resurfacing: Radiographic Evaluation Techniques

Hip resurfacing devices require a new radiographic evaluation technique owing to femoral components with short or no stems. Fourteen US surgeons implanted 1148 metal-on-metal hip resurfacing (HR) devices in a US-FDA-IDE clinical trial, which began in 2001. In this multi-center, prospective study, 337 patients (mean age, 50.1 years) were enrolled as a study group of unilateral HR arthroplasties. Radiographs of 292 HR arthroplasties at a minimum 2-year follow-up (maximum 3 years) were reviewed. There were 10 patients with radiographic evidence of femoral component instability beyond 2 years, as evidenced by subsidence ≥ 5mm. Of these, 7 did not have clinical symptoms associated with femoral component instability. In the study group, 24 revisions were reported, of which 8 were due to femoral neck fractures, 4 were due to acetabular component loosening, 11 were due to femoral component loosening, and 1 due to dislocation.

10 Years of Experience with Metal-On-Metal Hybrid Hip Resurfacing: A Review of 1000 Conserve Plus

Hip resurfacing is currently the fastest growing hip procedure worldwide. We reviewed 1000 hips in 838 patients who received a Conserve Plus (Wright Medical Technology, Inc., Arlington, Tenn) resurfacing at a single institution. The mean age of the patients was 50.0 years with 74.7% male. The hips were resurfaced irrespective of femoral defect size or etiology. The mean follow-up was 5.6 years (range, 1.1-11.0 years). All clinical scores improved significantly (P < .05). There was no acetabular component loosening. Ten were converted to total hip arthroplasty for femoral neck fracture, 20 for femoral loosening, 2 for sepsis, and 1 for recurrent subluxations. The 5-year survivorship was 95.2% with no failures in hips implanted since 2002. Short-term failures can be prevented. First-generation surgical technique and a low body mass index were the most important risk factors for the procedure. Improvements in bone preparation significantly increased prosthetic survival in hips with risk factors for failure.

The results of primary Birmingham hip resurfacings at a mean of five years

We report an independent prospective review of the first 230 Birmingham hip resurfacings in 212 patients at a mean follow-up of five years (4 to 6). Two patients, one with a loose acetabular component and the other with suspected avascular necrosis of the femoral head, underwent revision. There were two deaths from unrelated causes and one patient was lost to follow-up. The survivorship with the worst-case scenario was 97.8% (95% confidence interval 95.8 to 99.5). The mean Harris hip score improved significantly (paired t-test, p < 0.05) from 62.54 (8 to 92) pre-operatively to 97.7 (61 to 100) at a mean of three years (2.1 to 4.3), then deteriorated slightly to a mean of 95.2 (47 to 100) at a mean of five years. The mean flexion improved from 91.5 degrees (25 degrees to 140 degrees) to 110.4 degrees (80 degrees to 145 degrees) at a mean of three years with no further improvement at five years (111.2 degrees; 70 degrees to 160 degrees). On radiological review at five years, one patient had a progressive lucent line around the acetabular component and six had progressive lucent lines around the femoral component. A total of 18 femoral components (8%) had migrated into varus and those with lucent lines present migrated a mean of 3.8 degrees (1.02 degrees to 6.54 degrees) more than the rest. Superolateral notching of the femoral neck and reactive sclerosis at the tip of the peg of the femoral component were associated with the presence of lucent lines (chi-squared test, p < 0.05), but not with migration of the femoral component, and are of unknown significance. Our results with the Birmingham hip resurfacing continue to be satisfactory at a mean follow-up of five years.

Our First Experience with Extended Proximal Femoral Osteotomy for Revision Hip Surgery

The extended proximal femoral osteotomy (EPFO) is a demanding but useful technique for revision of both cemented or noncemented femoral components. Between 2000 and 2004 we performed extended proximal femoral osteotomy (EPFO) in 25 cases during revision hip surgery. The main indication for doing revision surgery was aseptic loosening of both total hip arthroplasty (THA) components (18 patients), whilst in the remaining 7 patients the indications were: aseptic loosening of acetabular component in three patients, septic loosening of THA in two patients, recurrent dislocation of the THA because of incorrectly positioned femoral component in one patient and aseptic loosening of cemented hip hemiarthroplasty in one patient. There were 14 women and 11 men. The mean follow-up was 22 months. The average time to revision was 8.3 years. The mean age at the time of revision was 70.3 years (range 55 to 81). At the time of the last control examination all osteotomy sites had healed with signs of remodelling. The mean time to union ranged from 11 weeks to 6 months, shown by the bridging callous formation in both radiographic projections. Bone remodelling occurred in all patients by 12 months and no complications such as nonunion, excessive fragment migration or wire breakage were found. In our experience, the extended proximal femoral osteotomy when properly indicated represents an efficient and reliable technique in revision hip surgery.