BACKGROUND

Despite many years of clinical experience the optimal bearing choice in total hip arthroplasty (THA) remains controversial. This study aims to directly compare the three widely used bearing surfaces: metal-on-highly crosslinked polyethylene (MoHXLPE), ceramic-on-ceramic (CoC) and metal-on-metal (MoM), regarding clinical and radiologic outcome parameters.

Introduction

The legacy constrained condylar knee prosthesis (LCCK, Zimmer.) is designed for primary and revision total joint arthroplasties that need additional stability due to ligament deficiency and to compensate for bone defects. In this follow-up we present our mid term results.

Background: Recently, the new phenomenon of “squeaking” noises emitted from THAs with ceramic-onceramic bearings has spared international interest. It shows a frequency of 0,7–19,5% in literature, but infrequently requires revision surgery. However, an even higher incidence of various other noises from those THAs audible to the human ear have become popular in the process: this noise can resemble clicking, grinding or creaking and can be caused by distinct movements, during longer periods of walking, or can be constant with movement. The incidence of those noises can reach up to 30% of THAs. However, memory has faded that other bearings like metal-on-metal and PE/ceramic have been associated with noises in the past.

Therefore we aimed to investigate the occurence of acoustic emissions in patients, who had all received the same implant but with alternate bearings, to investigate the nature of noise, duration and clinical consequence for all 3 bearings (polyethylene/ceramic, metalon-metal, ceramic-on-ceramic).

Method: Between 1999–2001, 360 patients were matched in a prospective randomised trial. All of them received a cementless Zimmer© Alloclassic Variall™ implant at the Orthopaedic Hospital Vienna – Speising, Austria with either a ceramic-on-ceramic bearing, a metal-on-metal bearing or a polyethylene/ceramic bearing. A questionnaire was sent via mail, including questions on first occurence of hip noise, information on the kind and duration of the phenomenon and possible adverse evaluation on behalf of the patient. In case of a positive report, the patient was invited to a clinical examination and radiographic analysis. In addition, a specialised audiography was conducted in patients with audible sensations. Finally, the SF-36 and WOMAC were analysed. A number of patients received further examination with methods of gait analysis in order to detect the distinct point of occurence of the noise during the gait cycle.

Results: 33 patients reported an audible phenomenon from their THA, 14 received a ceramic-onceramic bearing (Cerasul), 13 a polyethylene/ceramic bearing (Durasul) and 6 a metal-onmetal bearing (Metasul). The most common noise was a distinct clicking, followed by a creaking noise. Only 1 patient reported a squeaking sensation, he received a polyethylene/ceramic bearing.

Conclusion: The emission of specific noises from THAs of all bearings has been well documented in recent trials and could be verified in this survey of cementless THAs. No trend towards an increased incidence of noise from THAs with ceramic-on-ceramic bearings could be detected. Interestingly, the single case of „squeaking” was reported from a patient with polyethylene/ceramic bearing. Microseparation and subluxation of the femoral head with resulting edge loading and formation of stripe wear has recently been suspected as the main cause for “noisy hips.” So far 2 ceramic-on-ceramic hips of this study group population have been revised. Both articulations showed areas of stripe wear due to subluxation of the joint.

Aims: The aim of this study is to present long-term results of the cementless Alloclassic total hip arthroplasty system of up to 21 years.

Matarial and Methods: 152 consecutive primary hip arthroplasties using a threaded conical titanium cup (Alloclassic CSF) and a rectangular titanium press-fit stem (Alloclassic SL) were implanted between September 1987 and December 1988. In all cases a 32 mm alumina ceramic head and a UHMW polyethylene inlay were used. Clinical and radiological results were available for 55 patients (36,2%) with a minimum of 15 years (15.0 to 20.9 years). Clinical results were evaluated according to the Harris Hip Score, the SF-36 and WOMAC score. Radiographic results were analysed on anteroposterior x-rays according to the method of DeLee and Charnley for the cup and of Gruen for the stem.

Results: The average Harris Hip Score at the last follow-up was 87.3. The mean pain score was 41.5, the mean functional score 47.3. Radiographic results showed osteolytic lesions around the cup in one case. Radiolucent lines around the stem were observed only in the proximal zones in 2/3 of the cases, cortical hyperthrophy occurred in the distal zones in ¾ of the evaluated hips.

23 hips (15.1%) needed revision surgery. The majority (17 hips – 73.9% of all reoperations) were revised due to progressive Polyethylene wear, all after a minimum of ten years. Exchange of the polyethylene inlay and the ceramic head was performed in 14 hips. In two cases the acetabular component and in one case the femoral component were found to be loose intraoperatively because of the wear debris and had to be exchanged. 4 hips had to be revised due to aseptic cup loosening without signs of increased polyethylene wear. There was one revision due to a late deep infection and one because of a periprothetic femoral fracture.

Conclusion: Our data suggest that excellent long-term results can be achieved with the cementless Alloclassic system. The main limiting factor for implant survival was found in increased polyethylene wear. We therefore recommend early exchange of the inlay to avoid loosening and the use of modern wear couples such as ceramic-on-ceramic, metal-on-metal or crosslinked polyethylene.

Background: A continuing controversy in total knee arthroplasty is the question whether the posterior cruciate ligament should be retained or substituted. This report reviews a series of total knee arthroplasties with a fixed bearing posterior cruciate ligament retaining implant (Nex Gen^© CR, Zimmer Inc., Warsaw, IN).

Methods: Between May 1997 and April 2001 197 patients were provided with 218 primary implants. There were 142 females and 55 males with an average age of 71 years (range 53–88 years) and a BMI of 28,9 kg/m² (range 19,1–41,2 kg/m²). The diagnosis was osteoarthritis in 212 patients, 3 cases of aseptic osteonecrosis, 1 fracture of the tibia plateau, 1 prior infection and 1 psoriatic arthritis. 84 knees had prior operations including high tibial osteotomies and menisectomies.

The operations were performed by 11 surgeons, with more than 80% done by 5 surgeons. 162 (74%) femur components and 181 (83%) tibia components were cemented. Patella resurfacing was performed in 135 (62%) cases.

We evaluated the results prospectively with a clinical inspection, radiographs (AP and lateral, longleg standing, patella sunrise view), and the use of the Knee Society Score, Quality-of-Life Short Form-36 and WOMAC rating score.

149 patients were examined at a mean follow up of 5,9 years (range 4,1–8,2 years). 29 were questioned on the telephone, 29 deceased, 7 revisions had to be performed and 4 (2%) were lost to follow up.

Results: The range of motion improved from 101° to 115° (range 80°–140°). All knees had sufficient antero-posterior and mediolateral stability. The Knee society score improved from 35 to 83 (good result) and the function score improved from 52 to 76 (good result).

Early complications included 12 haematoma, 10 wound healing problems, 5 early infections, 2 thrombosis and 1 non lethal pulmonary embolism. 7 revisions had to be performed: 3 late infections (2 one-stage revisions with synovectomy and exchange of polyethylene inlay, one two-stage revision with semi-constrained implant LCCK© Zimmer Inc.), 3 patella resurfacing due to anterior knee pain and 1 exchange of cemented tibia plateau due to aseptic loosening. Survivorship at 6 years including any reason of failure was 96,5%.

Conclusion: At a mid term follow up of 6 years this fixed bearing posterior cruciate retaining implant achieved a reasonable survivorship with good clinical results, kinematics and patient satisfaction.

Aims: The aim of this study is to present clinical and radiographic long-term results including a survival analysis of the cementless Alloclassic total hip arthroplasty system.

Matarial and Methods: 103 consecutive primary hip arthroplasties using a threaded conical titanium cup (Alloclassic CSF) and a rectangular titanium pressfit stem (Alloclassic SL) were evaluated clinically and radiographically with an average follow-up period of 14.4 years (range 10.2 to 17.1 years). In all cases a 32 mm alumina ceramic head and a UHMW polyethylene inlay were used. Clinical results were evaluated according to the Harris Hip Score, the SF-36 and WOMAC score. Radiographic results were analysed on antero-posterior x-rays. A statistical survivorship analysis was calculated using Kaplan-Meier curves.

Results: The average Harris Hip Score at the last follow-up was 89.2. The mean pain score was 41.6, the mean functional score 47.6. Radiographic results showed a continuous radiolucency around the cup in three cases. Radiolucent lines around the stem were observed only in the proximal zone 1 in 52 and in zone 7 in 26 cases. Cortical hyperthrophy occurred in the distal zone 3 in 33 cases and in zone 5 in 72 cases. Fifteen hips were revised, eleven of them because of increased polyethylene wear after a minimum follow-up of 10 years. One patient needed revision due to a late deep infection after 7.4 years. There were three cases of aseptic loosening without signs of progressive polyethylene wear that led to a cup exchange. The cumulative survivorship with revision due to aseptic component loosening as endpoint was 95.6 % for the cup and 100 % for the stem after 15 years.

Conclusion: Our data suggest that excellent long-term results can be achieved with the cementless Alloclassic system. The main limiting factor for implant survival was found in increased polyethylene wear. We therefore recommend early exchange of the inlay to avoid component loosening and the use of modern wear couples such as ceramic-on-ceramic, metal-on-metal or crosslinked polyethylene.

Aims: Minimal invasive total hip replacement is supposed to allow a quicker rehabilitation in the immediate post-operative period due to reduced soft tissue damage. The aim of this study is to compare gait kinematics after total hip arthroplasty using a one incision minimal invasive approach to a traditional approach.

Matarial and Methods: 21 patients were available for a complete analysis. In 12 patients (MIS group) a minimal invasive, modified Watson-Jones approach was used, in 9 patients (Standard group) a transgluteal approach as described by Bauer was used. All operations were performed by a single surgeon with the patient in supine position. In all cases the same cementless implant (Alloclassic® VariallTM system) with standard instruments was used. 3D gait analysis was carried out pre-operatively, 10 days postoperatively and after 3 months. The variables analysed in this study were velocity, step length, range of hip extension, range of pelvic tilt, Trendelenburg’s sign and Duchenne limp, pelvic rotation and symmetry.

Results: There were no significant differences between the MIS and the Standard group in any of the evaluated variables. In both groups of the patients presented a decrease in the hip extension at the end of stance phase 10 days postoperatively. About half of these patients compensated with an increased sagital pelvic tilt during maximal hip extension. At the 3 months follow-up all patients in both groups had an increased hip extension compared to the preoperative values, reached normative values. The velocity was reduced in both groups at the 10 days follow-up, ¼ reached normative values after 3 months.

Conclusion: Our data show no significant improvement of gait kinematics in patients who underwent a total hip arthroplasty using a minimal invasive approach (modified Watson-Jones) compared to a standard approach (Bauer) during the early postoperative period.

Patients and methods: We obtained postoperative blood concentrations of Co, Cr, Mo, Ti, Al, Ni and Nb in 75 patients undergoing primary THA at our institution between January 1998 and December 2000. All patients were treated with the same prosthetic device (VARI-ALLTM, Zimmer, Winterthur, Switzerland) using three types of articulations: metal-on-metal (METASULTM), ceramic-on-ceramic (CERASULTM) and metal-on-cross linked polyethylene (DURASULTM). 25 patients out of each articulation-group were evaluated by blood analysis 24–38 months after surgery. The patients were submitted to strict criteria of inclusion.

Results: The Al-, Ti-, Ni- and Nb-blood levels were all below their detection limit. The median Co blood concentration in the ceramic group was 0.19 ng/ml, 0.69 ng/ml in the metal group and 0.19 ng/ml in the cross-linked PE group. The difference between the metal and ceramic group and between the metal and polyethylene group is statistically significant (p=0.001 in both comparisons). The median blood concentration of Cr was 0.19 ng/ml in the ceramic and in the cross-linked PE group, and 0.47 ng/ml in the metal group, the difference being statistically significant (p=0.003 and p=0.0002). Regarding the median blood concentrations of Mo, we found no statistically significant differences comparing the three articulations (p> 0.05). Comparing the three articulation-groups there were no significant differences in the categories age, follow up time and preoperative blood level of creatinine.

Conclusion: Although the blood concentrations of Co and Cr were significantly higher in patients with a metal-on-metal THA they were far from reaching toxic levels. Comparing our results using direct-conical metallic cup inserts with those of total hip devices with metallic sandwich-inlays blood concentrations of Co and Cr appear to be similarly elevated (Lhotka et al, J Orthop Res 2003).

Two Durasul highly crosslinked polyethylene liners were exchanged during revision surgery four and five years after implantation, respectively. The retrieved liners were evaluated macroscopically and surface analysis was performed using optical and electron microscopy. A sample of each liner was used to determine the oxidation of the material by Fourier transform infrared spectroscopy. Samples of the capsule were examined histologically.

The annual wear rate was found to be 0.010 and 0.015 mm/year, respectively. Surface analysis showed very little loss of material caused by wear. Histological evaluation revealed a continuous neosynovial lining with single multinucleated foreign-body giant cells. Our findings showed no unexpected patterns of wear on the articulating surfaces up to five years after implantation and no obvious failure of material.

Osteoarthritis is a slowly progressive musculoskeletal disorder that can occur in any joint and is characterised by symptoms of pain, stiffness or loss of function. Studies showed that the work related disability rate with osteoarthritis varied from 30 to 50%, it is also a frequent cause of early retirement.

Age is the strongest predictor of the development and progression of radiographic osteoarthritis. Further risk factors are physical activity, injuries, high bone mass index and intensive sport activities.

Targets that are most important in the prevention or management of osteoarthritis are to reduce pain, disability and to prevent radiological progression.

There are various life style factors that increase the risk of developing osteoarthritis, increase its rate of progression and may increase pain and functional limitation. Preventable or modifyable risk factors are obesity and mechanical aspects of the joint f.e. joint laxity or malalignment. Tears of menisci or ligaments may lead to at normal loading of articular cartilage and result in the increased deveopment of osteoarthritis. Further risk factors are certain occupations (f.e. farmers for hip- and knee osteoarthritis), intensive sport participation, muscle weakness and nutritional factors.

Pharmacological interventions are mainly to treat the symptom of pain and have nearly no effect on tissue damage. Nevertheless activity and participation is improved as well as using simple analgesics, antiinflammatory drugs, disease modifying therapies, hyaluronic acid and intraarticular steroids. There is no evidence that pharmacological interventions can prevent osteoarthritis as defined by radiological changes.

Biomechanic deficiencies may lead to joint damage and result in pain and disability. Therefore surgical correction of these abnormalities can relief pain and improve function. Further surgical interventions to reduce the impact of osteoarthritis include cartilage repair and joint preserving surgeries. For severely damaged joints, partial or total replacement of the joint is now possible for all those joints that are commonly affected by osteoarthritis.

Osteoarthritis is commonly associated with limited function that can be improved with a wide variety of rehabilitative interventions. Symptoms of pain may be reduced by joint specific exercises, transient immobilisation, heat or cold packings and braces or other devices. Further attention can be put on modifiying the environment as adaptions at home and at work, support services or other social interventions. Eduction and self managements play an important role as well in early as in late stages of the disease.

Background: There are many clinical and radiographic long term results of Total Hip Arthroplasties reported in literature but very few attend to the subjective quality of life of patients living with an implant. In the last few years different quality of life assessment scores were developed. In this study the subjective SF-36 and the WOMAC score were evaluated and the results were compared to the commonly used clinical Harris Hip Score.

Patients and methods: From a total number of 152 cement-less Total Hip Arthroplasties (Alloclassic®) performed between October 1987 and December 1988 at our clinic, 103 hips in 99 patients were available for a clinical and radiographic evaluation with an average follow-up of 14.3 years. For clinical evaluation the Harris Hip Score was used. Additionally all patients got SF-36 and WOMAC questionnaires. 78 questionnaires were returned fully completed and could be evaluated. The overall results and the results in the domain “pain” and “function” which occur in all three scores were compared statistically.

Results: The mean Harris Hip Score was 88.2 (range 24 – 100), pain score 41.9 and function score 48.4. The mean WOMAC Score was 10.6 in total, pain 2.8 and function 3.9. The SF-36 domain “Bodily Pain” was 56.6 and “physical function” 48.2. Concerning the domain “function” a significant correlation was found in all of the three scores (p < 0.01). A significant “pain” correlation was seen comparing the SF-36 to the WOMAC score (p < 0.01). No significant correlation was found comparing the clinical Harris Pain Score to the SF-36 domain “Bodily Pain” and to the WOMAC pain score.

Conclusion: In this study the subjective assessment questionnaires SF-36 and WOMAC show significant similar results to the clinical Harris Hip Score concerning the domain “function”. Concerning “Pain” comparable results were found between the SF-36 and the WOMAC with no significant correlation to the HHS. These data suggest that the quality of life assessment questionnaires can not replace the clinical evaluation using a clinical score.

We carried out a clinical and radiological review of 103 cementless primary hip arthroplasties with a tapered rectangular grit-blasted titanium press-fit femoral component and a threaded conical titanium acetabular component at a mean follow-up of 14.4 years (10.2 to 17.1).

The mean Harris hip score at the last follow-up was 89.2 (32 to 100). No early loosening and no fracture of the implant were found. One patient needed revision surgery because of a late deep infection. In 11 hips (10.7%), the reason for revision was progressive wear of the polyethylene liner. Exchange of the acetabular component because of aseptic loosening without detectable liner wear was carried out in three hips (2.9%).

After 15 years the survivorship with aseptic loosening as the definition for failure was 95.6% for the acetabular component and 100% for the femoral component.

The Chevron osteotomy was described in 1976. There have, however, been only short- to mid-term follow-up reviews, often with small numbers of patients.

We looked at 112 feet (73 patients) with a minimum follow-up of ten years following Chevron osteotomy with a distal soft-tissue procedure. Clinical evaluation was calculated using the hallux score of the American Orthopedic Foot and Ankle Society (AOFAS). For 47 feet (30 patients), the results were compared with those from an interim follow-up of 5.6 years.

The AOFAS-score improved from a pre-operative mean of 46.5 points to a mean of 88.8 points after a mean of 12.7 years. The first metatarsophalangeal (MTP) angle showed a mean pre-operative value of 27.6° and was improved to 14.0°. The first intermetatarsal (IM) angle improved from a pre-operative mean value of 13.8° to 8.7°. The mean pre-operative grade of sesamoid subluxation was 1.7 on a scale from 0 to 3 and improved to 1.2. Measured on a scale from 0 to 3, arthritis of the first MTP joint progressed from a mean of 0.8 to 1.7. Comparing the results in patients younger and older than 50 years, the Chevron osteotomy performed equally in both age groups. Analysing the subgroup of 47 feet with a post-operative follow-up of both 5.6 and 12.7 years, the AOFAS pain and the overall score showed a further improvement between both follow-up evaluations. The MTP angle, first IM angle and sesamoid position remained unchanged. The progression of arthritis of the first MTP joint between 5.6 and 12.7 years post-operatively was statistically significant. Only one patient required a revision procedure due to painful recurrence of the deformity.

Excellent clinical results following Chevron osteotomy not only proved to be consistent, but showed further improvement over a longer follow-up period. The mean radiographic angles were constant without recurrence of the deformity. So far, the statistically significant progression of first MTP joint arthritis has not affected the clinical result, but this needs further observation.

Aims: The purpose of this paper is to evaluate the effectiveness of cementless total hip arthroplasty using a threaded acetabular component with a titanium press þt stem. Methods: A total number of 179 cementless primary total hip arthroplasties was performed consecutively using a tapered rectangular gritblasted titanium press þt stem and a threaded conical titanium cup. Articulating wear partners were a ceramic ball head and an UHMW polyethylene inlay. At the time of evaluation with a minimum follow-up of 10 years 57 patients had died and 18 were not available for follow-up, thus leaving 104 consecutive, non-selected hips in 100 patients for clinical and radiographic examination after an average follow-up period of 11.6 years (range 10.0 to 14.2 years). Results: The average Harris Hip Score at the time of the latest follow-up was 88.7 (range 24 to 100). In 9 hips (5,0%) a revision was performed: in 6 cases (3,4%) the reason for revision was increased polyethylene wear. 2 cups (1,1%) were revised because of pain and radiographic signs of aseptic loosening without presence of increased wear. One hip had to be revised due to late deep infection after 7,2 years. All stem implants were rated stable. The probability of survival of both the ace-tabular and femoral component at 12 years with any reason for revision as endpoint was 94,8% (95% con-þdence interval). The survivorship with revision due to aseptic loosening of a component as endpoint was 97,7%. Conclusion: The design and material used for the threaded cup and tapered stem are decisive factors for the success of this cementless implant. With the above evaluated total hip system favourable long term results over a period of more than 10 years could be achieved.

Total knee arthroplasty is a predictable operation. Unfortunately, there is a subset of patients who do not well and require revision surgery. The surgical objective of revision total knee arthroplasty is the same as primary total knee arthroplasty: restore the original anatomy, restore function and provide a stable joint. The operation technique itself is a decisive for the success of arthroplasty as any type of malalignment may result in pain, instability or loosening of the implant.

1. REASONS OF FAILURE

The most important reason for revision total knee arthroplasty include aseptic loosening of one or both components. Early loosenings occur frequently as failures of ingrowth of a porous coated implant, while late loosenings mainly concentrate on cemented components, predominantly the tibial part. Another major reason for knee arthroplasties to fail is instability between the femur and tibia, caused by incorrect alignment or laxacity of the ligaments. Wear and osteolysis are the result of abnormally increased abrasion and plastic deformation of the polyethylene inlay. Usually this is a sequela of overloading through subluxation or deformity. It generally happens when the weight-bearing contact surfaces are small.

Pain around the patella may occur due to anterior displacmenet of the patellofemoral joint and is not related whether the patella remains natural or is totally replaced.

Rare complications are fatigue fractures of metallic components, femoral or tibial fractures around the implant, extreme limitation of motion or hyperextension of the joint.

The most severe complication is periprosthetic infection, which in most of the cases requires a one or two-stage revision procedure to replace the implant.

2. GOALS OF REVISION SURGERY

Correct axial and rotational alignment including the restoration of the right joint line is mandatory for the success of a revision total knee arthroplasty. Especially joint line elevation can result in functional disorders, therefore the use of distal femoral augmentation in revision has given more attention.

Balance of soft tissues to create equal flexion and extension spaces is another mandatory goal for revisions. Soft tissue releases can usually correct fixed angular deformities. Concerning balance by additional cuts of femoral or tibial bone one has to remember that adjustments on the femoral side can effect the knee in flexion or extension, whereas any adjustment on the tibial side will effect both. Minimize bone resection and achieving stability by stable fixation of all components of the implant are further prerequisits for the success of revision surgery.

Another criteria for success is correct patella tracking, which can on the one hand be solved by soft tissue procedures or by revising the implant. Even one has to change the femoral and tibial component, retaining a well fixed patella component appears to be a suitable option.

One of the most important criteria in revision total knee arthroplasty is implant selection. Recent publications have demonstrated that the implant-related failure rate was 25% when using implants designed for primary total knee arthroplasty, the failure rate of modified primary components was 14% and if components were used specially designed for revision the implant-related failure rate dropped to 6%. It was evident that revision implants exhibited superior performance and durability despite their use in more difficult reconstructions.

Concerning wear and osteolysis one should consider that an isolated revision of an polyethylene insert should not be performed when there is accelerated wear of the insert with severe delamination and radiographically under surface osteolysis.

The major objectives of bone grafting or augmentation blocks are filling in bony defects with biomechanically stable components to allow weight bearing and functional motion, to create an equal flexion and extension space for ligamentous stability and to restore a nearly anatomic joint line.

The use of intramedullary stems at revision surgery provides fixation of components into diaphyseal bone leading to increased stability for reconstruction. It produces axial alignment, the stems also partially relieve stresses on the deficient metaphyseal bone or allograft.

3. TREATMENT OF INFECTION

The incidence of periprosthetic infections is rather low. In early infections antibiotic treatment combined with open arthrotomy including debridement and exchange of inlay are the treatments of choice.

Late infections are best treated combining antibiotics and two stage exchange arthroplasty. Arthrodeses or amputations are extremely rare to indicate.

4. REVISIONS WITHOUT REPLACING THE IMPLANT

Many of these procedures belong to the patella including the removal of osteophytes, secondary release of the lateral patella retinaculum, secondary replacing the patella with an implant, or patellectomy.

The replacement of a worn tibial inlay is often combined with secondary synovectomy, sometimes heterotopic ossifications need to be removed for the improvement of mobility. In infected knees the placement of an inflow/outflow drain in an attempt to manage an acute periprosthetic infection or to provide relief of pain in the presence of sepsis.

We have compared different types of intertrochanteric osteotomy for avascular of necrosis of the hip and evaluated their performance in the light of improving outcome after total hip arthroplasty (THA). During a period of 14 years we performed 63 flexion osteotomies (partly combined with varus or valgus displacement), 29 rotational osteotomies, 13 varus osteotomies, eight medialising osteotomies and two extension osteotomies. The mean period of follow-up for all 115 operations was 7.3 years (maximum 24.6).

At follow-up, 27 of 29 patients with a rotational osteotomy had already undergone a THA, compared with 36 of 63 after flexion osteotomy. A high incidence of complications (55.2%) was seen early after rotational osteotomy, compared with 17.5% after flexion osteotomy.

For all osteotomies there was a high correlation between the size of the necrotic area and the incidence of failure, which also correlated with the preoperative Ficat and Steinberg stages. Using Kaplan-Meier survivorship analysis, Sugioka’s rotational osteotomy showed a survival probability after five years of 0.26 (95% confidence interval 0.49 to 0.14), and after ten years of 0.15 (CI 0.36 to 0.06). The survival probability for flexion osteotomy was 0.70 (CI 0.83 to 0.59) after five years and 0.50 (CI 0.65 to 0.38) after ten years. The subgroup of flexion osteotomy with a necrotic sector of less than 180° achieved the best survival probability of 0.90 (CI 1.00 to 0.80) after five years and 0.61 (CI 0.84 to 0.45) after ten years.

The indications for intertrochanteric osteotomy for avascular necrosis of the hip have to be addressed critically. Even flexion osteotomy in cases with small areas of necrosis provides only temporary benefit. Rotational osteotomy was associated with a high incidence of complications.

We revised seven alumina-blasted cementless hip prostheses (Ti-alloy stems, cp Ti threaded sockets) with low- or high-carbon Co-alloy bearings at a mean of 20.1 months after implantation because of pain and loosening. Histological examination of the retrieved periprosthetic tissues from two cases in which the implant was stable and three in which the socket was loose showed macrophages with basophilic granules containing metal and alumina wear particles and lymph-cell infiltrates. In one of the two cases of stem loosening the thickened neocapsule also contained definite lymphatic follicles and gross lymphocyte/plasma-cell infiltrates. Spectrometric determination of the concentration of elements in periprosthetic tissues from six cases was compared with that of joint capsules from five control patients undergoing primary hip surgery. In the revisions the mean concentration of implant-relevant elements was 693.85 μg/g dry tissue. In addition to Cr (15.2%), Co (4.3%), and Ti (10.3%), Al was predominant (68.1%) and all concentrations were significantly higher (p < 0.001) than those in the control tissues. The annual rates of linear wear were calculated for six implants. The mean value was 11.1 μm (heads 6.25 μm, inserts 4.82 μm). SEM/EDXA showed numerous fine scratches and deep furrows containing alumina particles in loosened sockets, and stems showed contamination with adhering or impacted alumina particles of between 2 and 50 μm in size.

We report the clinical and tribological performance of 67 ceramic acetabular prostheses implanted between 1976 and 1979 without bone cement. They articulated with ceramic femoral heads mounted on mental femoral stems. After a mean elapsed period of 144 months, 59 sockets were radiographically stable but two showed early signs and six showed late signs of loosening. Four of the loose sockets have been revised. Histological analysis of the retrieved tissue showed a fibrous membrane around all the implants, with fibrocartilage in some. There was no bone ingrowth, and the fibrous membrane was up to 6 mm thick and infiltrated with lymphocytes, plasma cells, and macrophages. Intra- and extracellular birefringent wear particles were seen. Tribological analysis showed total wear rates in two retrieved alumina-on-alumina joints of 2.6 microns per year in a stable implant and 68 microns in a loose implant. Survival analysis showed a revision rate of 12.4% at 136 months.