We have investigated nine patients with cemented Furlong (JRI, London, UK) titanium hip replacements who presented with early pain despite a well-fixed, aseptic prosthesis. All were followed up clinically and radiologically at regular intervals. Pain was located in the thigh and was worse at night. Radiographs showed cortical hypertrophy of the femur around the tip of the stem. Eight of the nine patients subsequently required single-stage revision using an uncemented prosthesis, which relieved the pain. At revision, the pH of the tip of the stem was found to be highly acidic with macroscopic evidence of corrosion consisting of multiple layers of titanium oxides when studied by X-ray dispersive analysis. Cemented titanium implants have a potential for crevice corrosion leading to cortical hypertrophy and intractable pain

One hundred hips in patients who had had primary uncemented replacements were followed up for one or two years, and assessed by five different methods. All produced different results. The Hospital for Special Surgery rating produced the most optimistic assessment and the Merle d'Aubigne rating the most pessimistic. The functional class of the patients, as defined by Charnley in 1979, significantly affected the ratings, and these should clearly be included in all rating systems. Moreover, if systems are to be compared, they should all use descriptive words, such as limp or pain, in precisely the same way

The Kodama-Yamamoto knee is an uncemented surface replacement which has been used since 1970. The design has been improved twice and this present report concerns the results of the Mark II model. Between 1980 and 1984, 350 knees were replaced in 225 patients. In 1987, a survey of 335 of these knees was conducted at two to seven years after operation. The results were excellent or good in 83% of patients. Many of the failures were because of general disorders unrelated to the operation, but in 5.4% of the knees there were local complications which continue to present problems

Thirty-seven patients with extensive acetabular defects due to loose implants had revisions with uncemented components, the acetabulum being augmented with homograft bone. In six of these, a histological study of graft incorporation was made. At a mean follow-up of 1.5 years 34 patients were free of pain and 35 could walk for 30 minutes or longer. No graft had obviously sequestrated. Two components had radiological evidence of migration but remain asymptomatic. We conclude that cementless revision surgery with homograft supplementation of the acetabulum is clinically successful in the short-term. The long-term outcome is unknown

Nine uncemented hip prostheses of modular design were revised because of late infection (2 cases), femoral stem loosening or fracture (2), loosening of threaded cups (3) and protrusion of bipolar cups (2). At surgery we found tissue discoloration and macroscopic corrosion in four of the nine prostheses, located at the head-neck junction. Histological examination in most cases showed extensive necrosis associated with metal particles, indicating metal toxicity. Metallographic examination of the prosthetic heads revealed structural imperfections and inhomogeneity of the metal. We suggest that the crevice between the head and neck is a potential site of corrosion in modular designs

We assessed 100 patients with a primary total hip replacement using the Harris hip score and the Nottingham Health Profile at one, three and five years after operation. They were derived from two prospective randomised series of cemented and uncemented replacements. Both scoring systems correlated highly and were each heavily influenced by the system of functional classification defined by Charnley. After five years both reflected the function of the implant and the general state of the patient. A higher degree of sensitivity is needed to show differences in the performance of an implant in the short and medium term. We do not yet have an ideal system of clinical assessment and the overall function must always be properly assessed

Aims

The aim of this study was to assess the functional gain achieved following hip resurfacing arthroplasty (HRA).

Retrospective review of 730 consecutive primary uncemented and cemented total hip arthroplasties revealed 19 intra-operative hoop-stress fractures of the femoral neck. These were incomplete, linear, and minimally displaced. Management was by cerclage wiring (12), bone graft and cerclage (two), further impaction (two), and the use of cement (three), with no change from our standard postoperative management and rehabilitation. Eighteen patients had excellent or good results with an average Harris hip score of 93. Radiographically, all but one patient had Engh stability-fixation scores consistent with stable bone ingrowth. We conclude that hoop-stress fractures of the proximal femur, properly managed, do not detract from the results of total hip arthroplasty

Torsional instability of femoral components has not received much attention, and is difficult to detect in conventional radiographs. To test this we designed a system to apply a load in an anteroposterior direction to the head of a femoral component, implanted into a cadaveric femur. Rotation within the bone was measured, using a purpose built transducer, with and without preservation of the neck, with and without cement, and with longitudinal ridges but no cement. The results show that torsional instability may be a problem in uncemented replacement. Preservation of the femoral neck and the use of a ridged prosthesis increases resistance to rotation. Rotational movements occurring in vivo during such activities as climbing stairs and rising from the seated position may contribute to mechanical loosening

We describe 25 patients who were treated for a tumour of the proximal femur by resection and replacement with an uncemented, bipolar, modular prosthesis. When followed up after more than ten years four prostheses (16%) had required revision. Two joints showed wear and another necrosis of the acetabulum. One patient with loosening of the stem had been treated by radiotherapy to the femur. Articular cartilage seemed to be a reliable barrier to acetabular wear. Very few signs of the formation of particulate debris were observed. The most obvious feature in the bone-stem relationship was stress shielding, seen as osteoporosis of the proximal part of the femur around the stem in 68%. Functional activity was satisfactory in 68% of the patients. A better system of reattachment of the soft tissues is needed to avoid pain and a persistent limp

We report our results in 24 children with malignant primary bone tumours of the distal femur treated with a Stanmore extendible endoprosthesis (SEER). This consists of a femoral component that can be lengthened, a constrained knee and an uncemented sliding tibial component which crosses the proximal tibial physeal plate perpendicularly. The average age of the patients at diagnosis was ten years and the mean follow-up was 4.7 years (2.5 to 7.9). The mean growth of the affected tibia was 76% (18 to 136) and of the fibula 83% (15 to 750) of the growth of the unaffected limb. Measurement of growth arrest lines showed that the mean growth of the proximal tibial physis on the affected side was 69% (43 to 100) of that of the normal side. The great variability in the growth of the physis cannot yet be explained

We have investigated the ability to kneel after total knee replacement. We asked 75 patients (100 knees) at least six months after routine uncemented primary total knee replacement, to comment on and to demonstrate their ability to kneel. Differences between the perceived and actual ability to kneel were noted. In 32 knees patients stated that they could kneel without significant discomfort. In 54 knees patients avoided kneeling because of uncertainties or recommendations from third parties (doctors, nursing staff, friends, etc). A total of 64 patients was actually able to kneel without discomfort or with mild discomfort only and 12 of the remainder were unable to kneel because of problems which were not related to the knee. Twenty-four patients therefore were unable to kneel because of discomfort in the knee. There was no difference between the ‘kneelers’ and ‘non-kneelers’ with regard to overall knee score, range of movement and the presence of patellar resurfacing

A leading problem with cementless hip replacement is thigh pain, probably due to some degree of loosening. This is most pronounced during activities such as stair climbing or getting up from a chair. Our study compares the immediate fixation of three stems in widespread clinical use, using a cadaver test simulation in which the femur was horizontal, and cyclic forces acted vertically downward on the prosthetic head with gradual increments of load. We implanted and tested 18 pairs of femurs, making analyses between stem types by right to left comparisons. We found no statistically significant differences in loosening between cementless AML and PCA prostheses, but cemented stems withstood greater loads than uncemented stems by a factor of five or more

Aims

In previous studies, we identified multiple factors influencing the survivorship of hip resurfacing arthroplasties (HRAs), such as initial anatomical conditions and surgical technique. In addition, the University of California, Los Angeles (UCLA) activity score presents a ceiling effect, so a better quantification of activity is important to determine which activities may be advisable or detrimental to the recovered patient. We aimed to determine the effect of specific groups of sporting activities on the survivorship free of aseptic failure of a large series of HRA.

In 16 patients we used uncemented Lord prostheses at revision operations for aggressive granulomatosis after cemented hip arthroplasties; in 12 bone grafts also were used. In 13 hips the granulomatous lesions were multifocal, and in one the acetabular component was involved. There was no evidence of infection in any case: all the patients had normal ESR and CRP levels. The revision operation was performed on average 9.4 years after the primary replacement; the mean age at revision was 64 years. On radiographs, the bone around the prosthesis had consolidated by an average of 16 months. At follow-up, two to six years later (mean 3.5 years) there had been no recurrences, nine patients had an excellent Mayo hip score, five were good and two fair

Total hip replacement was performed in 27 hips of patients who had sickle cell anaemia with avascular necrosis of the femoral head. The disease was bilateral in 11 patients. Considerable medical problems were encountered although most of the patients had exchange transfusion before surgery (86%), which prevented postoperative sickle cell crises in all but two cases. At the primary operation hard sclerotic bone was seen in nine femora with complete obliteration of the femoral canal. There were four femoral fractures, three following perforation of the shaft due to this hard bone. There was a very high morbidity due to loosening in both cemented and uncemented prostheses. With a rate of 59% over a cumulative 5.5 year period, revision was being performed at an average of only 43 months. Surgeons should be aware of these problems

Implants of solid sintered hydroxyapatite form very tight bonds with living bone, but are susceptible to fatigue failure. This problem can be overcome by using plasma-sprayed apatite coatings on titanium implants. A very strong bond is formed between bone and this composite material; this was studied in canine bone with plug implants, avoiding any mechanical retention. Mechanical testing showed an interface shear strength at six weeks of 49 MPa with a maximum of 64 MPa after six months. There was histological evidence of direct bonding between the apatite coating and living bone while uncoated control plugs were easily extracted. The results indicate that apatite-coated implants can form a chemical fixation with a strength comparable to that of cortical bone itself. This fixation is far stronger than that provided by current cemented or uncemented fixation techniques

We carried out 60 revision procedures for failed porous coated anatomic total knee replacements in 54 patients, which were divided into two groups. The 14 knees in group I had a well-fixed femoral component at surgery which was retained, and in the 46 knees in group II both tibial and femoral components were loose and were revised using a variety of implants. Our review comprised clinical and radiological assessment. A total of 13 knees required a second revision. Six (42%) in group I failed very early (mean 2.1 years) when compared with seven (15%) in group II (mean 6.8 years). Failure was due to wear of the polyethylene insert by the abraded, retained femoral component (crude odds ratio 4.07; 95% CI 1.07 to 15.5). We recommend a complete change of primary bearing surfaces at the time of revision of an uncemented total knee replacement in order to prevent early wear of polyethylene