Using 26 cadaver shoulders, we produced a standard defect in the supraspinatus tendon and performed one of three types of repair. Their strength was found by testing in tension the force required to produce a gap of 3 mm, then 6 mm, and finally total disruption of the repair. The use of a polyethylene patch to spread the forces over the lateral bone surface and of extra sutures to grasp the tendon end raised by 2.6 times the load at which a 3 mm gap in the repair occurred and by 1.7 times the load to failure

We performed an independent survivorship analysis on 208 Kinematic Condylar knee replacements with a minimum follow-up of ten years and a mean of 12 years. Seven patients had been lost to follow-up. At ten years the estimated survival was 92% (95% confidence limits 95% and 87%) and when stratified for diagnosis and thickness of polyethylene there was no statistical difference (p > 0.05) in survivorship of knees with osteoarthritis or rheumatoid arthritis. We conclude that the original design of the Kinematic Condylar knee replacement has a good record and that adequate evaluation of new designs of implant should be undertaken before they are widely introduced

We studied the effect of a metal tray with an intramedullary stem on the micromotion of the tibial component in total knee arthroplasty. Of 32 uncemented Freeman-Samuelson knee arthroplasties performed in London and Gothenburg, nine had a metal backing and stem added to the tibial component. Micromotion of the tibial components, expressed as migration and inducible displacement, was analysed using roentgen stereophotogrammetric analysis up to two years follow-up. The addition of a metal back and a 110 mm stem to the standard polyethylene component significantly reduced both migration over two years and inducible displacement

Aims

The aim of this study was to describe, analyze, and compare the survival, functional outcome, and complications of minimally invasive (MI) and non-invasive (NI) lengthening total femoral prostheses.

This paper presents a prospective trial carried out using the Monk "soft top" endoprosthesis in 33 patients. Two years after operation 70 per cent of the remaining patients had pain. A biomechanical and histopathological analysis of the endoprosthesis and the surrounding tissue, obtained from a further two patients at the time of revision, is presented. It is concluded that the prosthesis has inherent design faults which result in excessive wear of the polyethylene component. The wear debris produced stimulates a prolific fibrous tissue reaction which is associated with progressive clinical deterioration

Fixation of the glenoid component is critical to the outcome of total shoulder arthroplasty. In an in vitro study, we analysed the effect of surface design and thickness of the cement mantle on the pull-out strength of the polyethylene pegs which are considered essential for fixation of cemented glenoid components. The macrostructure and surface of the pegs and the thickness of the cement mantle were studied in human glenoid bone. The lowest pull-out forces, 20 ± 5 N, were for cylindrical pegs with a smooth surface fixed in the glenoid with a thin cement mantle. The highest values, 425 ± 7 N, were for threaded pegs fixed with a thicker cement mantle. Increasing the diameter of the hole into which the peg is inserted from 5.2 to 6.2 mm thereby increasing the thickness of the cement mantle, improved the mean pull-out force for the pegs tested

Aims

The hypothesis of this study was that thigh circumference, distinct from body mass index (BMI), may be associated with the positioning of components when undertaking total hip arthroplasty (THA) using the direct anterior approach (DAA), and that an increased circumference might increase the technical difficulty.

We report two cases of surface deterioration of a zirconia ceramic femoral head associated with phase transformation after total hip arthroplasty. One head was retrieved at revision due to recurrent dislocation after six years and the other because of failure of the locking mechanism of the polyethylene liner after three years. The monoclinic content of the zirconia ceramics rose from 1% to about 30% on the surface of the heads. SEM revealed numerous craters indicating extraction of the zirconia ceramics at the surface. Surface roughness increased from an initial value of 0.006 3m up to 0.12 3m. This is the first report to show that phase transformation of zirconia ceramics causes deterioration of the surface roughness of the head in vivo after total hip arthroplasty

Aims

It is important to consider sagittal pelvic rotation when introducing the acetabular component at total hip arthroplasty (THA). The purpose of this study was to identify patients who are at risk of unfavourable pelvic mobility, which could result in poor outcomes after THA.

Aims

Patients with a failed reverse shoulder arthroplasty (RSA) have limited salvage options. The aim of this study was to determine the outcome of revision RSA when used as a salvage procedure for a failed primary RSA.

We report the results of 24 acetabular reconstructions in which cemented polyethylene cups and tamped corticocancellous allografts were used for severe acetabular bone deficiency. Eleven hips had type-II (cavitary) bone deficiency and 13 had type-III (combined) defects. At a mean follow-up of 5.8 years, two components had migrated more than 5 mm and had accompanying radiolucent zones of more than 2 mm width. A radiolucency 5 mm wide was also seen in zone III of an acetabular implant which had not migrated. None of the patients had required revision because of loosening or infection

Aims

Displaced, comminuted acetabular fractures in the elderly are increasingly common, but there is no consensus on whether they should be treated non-surgically, surgically with open reduction and internal fixation (ORIF), or with acute total hip arthroplasty (THA). A combination of ORIF and acute THA, an approach called ’combined hip procedure’ (CHP), has been advocated and our aim was to compare the outcome after CHP or ORIF alone.

Using a rat model, we created a bone-to-titanium interface and applied phagocytosable high-density polyethylene pArticles between the bone and implant, either initially or when the interface had matured. No fibrous membrane developed and no bone resorption was found. If sliding movements were initiated at the interface after two weeks, there was formation of a fibrous membrane. The additional application of pArticles did not change the thickness of the membrane, and there were only minor qualitative changes. Creation of a membrane by movement followed by cessation of movement and the application of pArticles caused the membrane to persist, whereas in a pArticle-free control group bone-to-metal contact was re-established. Our findings suggest that mechanical stimuli are of primary importance for prosthetic loosening, and that pArticles may modulate the later stages of the loosening process

Twenty patients were examined by standard radiography and roentgen stereophotogrammetric analysis (RSA) during a two-year period after total hip arthroplasty. Eleven of the acetabular components migrated cranially and three femoral components migrated distally. This migration was most rapid during the first four months after operation. Our findings support the possibility that mechanical loosening is initiated by thermal injury during polymerisation of the cement; the less frequent migration of the metallic femoral component compared with the polyethylene acetabular component may be because the metal acts as a heat sink. Standard radiographs were inadequate for assessment of early mechanical loosening, whereas RSA could reveal migration within four months of the arthroplasty

Aims

The aim of this study was to report the outcomes of different treatment options for glenoid loosening following reverse shoulder arthroplasty (RSA) at a minimum follow-up of two years.

We made a semiquantitative study of the comparative histology of pseudomembranes from 12 loose cemented ceramic-ceramic and 18 metal-polyethylene total hip replacements. We found no significant difference in cellular reaction between the two groups, but there was a major difference in the origin of the particulate debris. In the metal-polyethylene group, polyethylene of articular origin was predominant, while in the ceramic-ceramic group the cellular reaction appeared to be a response to zirconia ceramic particles used to opacify cement used for fixation. Isolation and characterisation of the debris showed that the zirconia particles formed the greatest proportion (76%) in ceramic-ceramic hips, while alumina debris of articular origin formed only 12%. Our study has indicated that aseptic loosening of ceramic cups is not due to a response to debris generated at the articular interface, but to mechanical factors which lead to fragmentation of the cement

Aims

Local antibiotics are used in the surgical management of foot infection in diabetic patients. This systematic review analyzes the available evidence of the use of local antibiotic delivery systems as an adjunct to surgery.

We studied the stability of cemented all-polyethylene keeled glenoid components by radiostereometric analysis (RSA) in 16 shoulders which had received a total shoulder replacement. There were 14 women (one bilateral) and one man with a mean age of 64 years. The diagnosis was osteoarthritis in eight and rheumatoid arthritis in seven. Two of the shoulders were excluded from the RSA study because of loosening of the tantalum markers. Three tantalum markers were inserted in the glenoid socket, two in the coracoid process and two in the acromion. The polyethylene keeled glenoid component was marked with three to five tantalum markers. Conventional radiological and RSA examinations were carried out at five to seven days, at four months and at one and two years after operation. Radiolucent lines were found in all except three shoulders. Migration was most pronounced in the distal direction and exceeded 1 mm in four shoulders. In ten shoulders rotation exceeded 2° in one or more axes with retroversion/anteversion being most common. No correlation was found between migration and the presence of radiolucencies on conventional radiographs

We present a prospective review of the outcome of 76 Lubinus patellofemoral arthroplasties carried out in 59 patients between 1989 and 1995. At a mean follow-up of 7.5 years, 62 knees in the 48 patients were reviewed; 11 patients (14 knees) had died. None was lost to follow-up. The clinical outcome using the Bristol Knee Scoring system was satisfactory in 45% of the cases. Maltracking of the patella, resulting in lateral tilt, subluxation and polyethylene wear, was the most common complication (32%). Revision surgery was carried out in 21 knees (28%) giving a cumulative survival rate of 65% (confidence interval (CI) 49 to 77) at eight years. The survival rate for revision and moderate pain was 48% (CI 36 to 59) at six years. Progression of arthritis was seen in seven cases (9%). In five of these (6.5%), the symptoms were severe enough to need revision surgery. Due to the high proportion of unsatisfactory results, we have discontinued the use of this prosthesis