Osteolysis is due to particulate wear debris and is responsible for the long-term failure of total hip replacements. It has stimulated the development of alternative joint surfaces such as metal-on-metal or ceramic-on-ceramic implants. Since 1988 the second-generation metal-on-metal implant Metasul has been used in over 60 000 hips. Analysis of 118 retrieved specimens of the head or cup showed rates of wear of approximately 25 μm for the whole articulation per year in the first year, decreasing to about 5 μm per year after the third. Metal surfaces have a ‘self-polishing’ capacity. Scratches are worn out by further joint movement. Volumetric wear was decreased some 60-fold compared with that of metal-on-polyethylene implants, suggesting that second-generation metal-on-metal prostheses may considerably reduce osteolysis

Aims

The optimum clearance between the bearing surfaces of hip arthroplasties is unknown. Theoretically, to minimize wear, it is understood that clearances must be low enough to maintain optimal contact pressure and fluid film lubrication, while being large enough to allow lubricant recovery and reduce contact patch size. This study aimed to identify the relationship between diametrical clearance and volumetric wear, through the analysis of retrieved components.

We determined serum cobalt levels in 55 patients by atomic absorption spectrophotometry before and after implantation of uncemented total hip arthroplasties. In a randomised, prospective trial 27 wrought Co-28Cr-6Mo-0.2C metal-on-metal articulations were compared with 28 ceramic-on-polyethylene hips which did not contain cobalt. Other sources of iatrogenic cobalt loading were excluded. The metal-on-metal group produced detectable serum cobalt levels (median 1.1 μg/l after one year) which were significantly different (p < 0.0001) from those of the ceramic-on-polyethylene control group (median below detection limit of 0.3 μg/l after one year). Our findings indicate that metal-on-metal bearings generate some systemic release of cobalt

1. A technique of transarticular nailing for subcapital and transcervical fractures of the neck of the femur is described. 2. Forty-four operations have been done, and twenty-one patients have been under observation for periods of from one to six years. In one of these pseudarthrosis has developed; in two others there has been delayed union. 3. The method gives sound fixation by a "squeezing effect" on the proximal fragment, which is enhanced by the locking of the adjacent articulation. 4. It is presented as an alternative to prosthetic replacement for treatment of femoral neck fracture in the aged. The nail damages the articular surface of the acetabulum but not the femoral head. 5. The importance of care after operation is stressed. 6. The advantages of the method, the role of circulatory changes in the femoral head and the mechanics of transarticular fixation are discussed

Destruction of the articular cartilage is the first change seen on gross examination of the knee in osteoarthritis. Weight-bearing radiographs are conventionally taken with the knee in full extension. Biomechanical studies have shown, however, that the major contact stresses in the femorotibial articulation occur when the knee is flexed about 28 degrees. Arthroscopy has confirmed that cartilage loss occurs in a more posterior portion of the femoral condyles than is revealed by radiographs taken in full extension. The 'standing tunnel view' is a weight-bearing postero-anterior radiograph taken with the knee in 30 degrees of flexion. The radiographs of 64 patients have been used to compare the conventional with the standing tunnel view. In 10 knees in which the conventional view suggested normal cartilage the standing tunnel view revealed severe degeneration

Aims

Total knee arthroplasty is an established treatment for knee osteoarthritis with excellent long-term results, but there remains controversy about the role of uncemented prostheses. We present the long-term results of a randomized trial comparing an uncemented tantalum metal tibial component with a conventional cemented component of the same implant design.

This is a preliminary report of the results of knee joint replacements using the Liverpool Mark II knee joint system which consists of a bicondylar prosthesis and a set of stereotactic instruments. The prosthesis has been developed from Gunston's concept, and the special instruments ensure its accurate insertion through meniscectomy-type incisions placed on either side of the patella. Particular features of the prosthesis are near-normal articulation, and the simplicity of the operation. Sixty-two knee replacements were implanted in forty-two patients between the spring of 1974 and January 1977. After the operation fifty-six knees were painless and four others produced only slight pain. Full extension was obtained in fifty-eight knees, and none showed a valgus or varus deformity. Collateral laxity was absent in all knees. There were two failures. These early results are most encouraging

Using a new, non-invasive method, we measured the patellofemoral force (PFF) in cadaver knees mounted in a rig to simulate weight-bearing. The PFF was measured from 20° to 120° of flexion before and after implanting three designs of knee prosthesis. Medial unicompartmental arthroplasty with a meniscal-bearing prosthesis and with retention of both cruciate ligaments caused no significant change in the PFF. After arthroplasty with a posterior-cruciate-retaining prosthesis and division of the anterior cruciate ligament, the PFF decreased in extension and increased by 20% in flexion. Implantation of a posterior stabilised prosthesis and division of both cruciate ligaments produced a decrease in the PFF in extension but maintained normal load in flexion. There was a direct relationship between the PFF and the angle made with the patellar tendon and the long axis of the tibia. The abnormalities of the patellar tendon angle which resulted from implantation of the two total prostheses explain the observed changes in the PFF and show how the mechanics of the patellofemoral joint depend upon the kinematics of the tibiofemoral articulation

We report our experience over seven years with a floating radial-head prosthesis for acute fractures of the radial head and the complications which may result from such injury. The prosthesis has an integrated articulation which allows change of position during movement of the elbow. We present the results in 12 patients with a minimum follow-up of two years. Five prostheses had been implanted shortly after injury with an average follow-up of 49 months and seven for the treatment of sequelae with an average follow-up of 43 months. All prostheses have performed well with an improved functional score (modified from Broberg and Morrey 1986). We have not experienced any of the complications previously reported with silicone radial-head replacement. Our initial results suggest that the prosthesis may be suitable for the early or delayed treatment of Mason type-III fractures and more complex injuries involving the radial head

Aims

Extracellular matrix (ECM) and its architecture have a vital role in articular cartilage (AC) structure and function. We hypothesized that a multi-layered chitosan-gelatin (CG) scaffold that resembles ECM, as well as native collagen architecture of AC, will achieve superior chondrogenesis and AC regeneration. We also compared its in vitro and in vivo outcomes with randomly aligned CG scaffold.

We report the 12 to 74 month results of our mark I saddle prosthesis after its use as a salvage device for gross loss of pelvic bone stock in 76 patients with failed hip arthroplasties. The implant transmits load between iliac bone and bare polish chrome-cobalt. Our clinical and radiological results indicate that a useful and stable articulation can be achieved in most cases, provided that continued deep infection can be avoided. The appearance of radiological sclerosis at the bearing site in successful cases seems to indicate that significant late migration will not occur. Based on our experience with the mark I prosthesis we have designed and developed a mark II model which has freedom of axial rotation of the saddle. Our early results in 40 cases show a significant improvement over the results which could have been predicted for the mark I device

1. Radiographs of both shoulders were performed on 106 unselected necropsy subjects and those found to be abnormal were examined pathologically. 2. Radiological abnormalities were found in sixty-eight shoulders of thirty-eight subjects. Pathological examination showed rotator cuff tears and associated abnormalities in thirty-five of these, rheumatoid arthritis in one, a previous fracture in one, and one was not examined. 3. The criteria for radiological diagnosis of rotator cuff tears are examined and discussed. 4. The radiological changes give little indication of the severity of the tears or associated abnormalities except in the case of complete rupture of the cuff when acromio-humeral articulation occurs. 5. The lesions are all explicable on a traumatic basis. There is no correlation with the presence or absence of osteoarthritic disease of the joint. 6. The biceps tendon may become damaged or even ruptured in this condition. 7. Villous synovial proliferation was found in fourteen cases, in five of which it was pigmented with histological appearances resembling pigmented villonodular synovitis. The significance of this finding is briefly discussed

Aims

Patients with abnormal spinopelvic mobility are at increased risk for instability. Measuring the change in sacral slope (ΔSS) can help determine spinopelvic mobility preoperatively. Sacral slope (SS) should decrease at least 10° to demonstrate adequate posterior pelvic tilt. There is potential for different ΔSS measurements in the same patient based on sitting posture. The purpose of this study was to determine the effect of sitting posture on the ΔSS in patients undergoing total hip arthroplasty (THA).

Aims

This combined clinical and in vitro study aimed to determine the incidence of liner malseating in modular dual mobility (MDM) constructs in primary total hip arthroplasties (THAs) from a large volume arthroplasty centre, and determine whether malseating increases the potential for fretting and corrosion at the modular metal interface in malseated MDM constructs using a simulated corrosion chamber.

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The purpose of this study is to examine six types of bearing surfaces implanted at a single institution over three decades to determine whether the reasons for revision vary among the groups and how long it takes to identify differences in survival.

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Patients may present with concurrent symptomatic osteoarthritis (OA) of the hip and degenerative disorders of the lumbar spine, with surgical treatment being indicated for both. Whether arthroplasty of the hip or spinal surgery should be performed first remains uncertain.

Aims

Modular dual-mobility constructs reduce the risk of dislocation after revision total hip arthroplasty (THA). However, questions about metal ions from the cobalt-chromium (CoCr) liner persist, and are particularly germane to patients being revised for adverse local tissue reactions (ALTR) to metal. We determined the early- to mid-term serum Co and Cr levels after modular dual-mobility components were used in revision and complex primary THAs, and specifically included patients revised for ALTR.

The discrepancy between successful experimental studies of cartilage repair and the clinical results is unexplained. We have evaluated the effect of metabolic alterations in joint homeostasis owing to an articular defect on the outcome of cartilage repair using tissue engineering methods. We used 21 adolescent Dutch goats divided into three groups. The control knees were left untreated while the contralateral knee was randomised to receive either no treatment (N), early treatment (E) or late treatment (L). The metabolism of proteoglycans in the surrounding joint surface was determined and correlated with the O’Driscoll score used to quantify the histological aspect of the repair of the defect. Synthesis of proteoglycan (PG) was increased in all groups. The release of glucosaminoglycan (GAG) was significantly higher in the untreated but not after early transplantation (1.3 v 1.8 NS). The cartilage repair scores in the early treatment group were not as good as those of the normal control group, but were significantly better when compared with both the untreated defects and the late treated defects. Defects which had been treated late showed a significantly decreased score when compared with those which had had early treatment or the normal control group and did not differ (p = 0.12) from those with no treatment. The histological and biochemical scores closely resembled the macroscopic and functional parameters which showed a significant deterioration for the late treated group and those without treatment compared with animals treated early. Thus, tissue-engineered cartilage repair is negatively influenced by altered matrix metabolism. Early treatment showed significantly better results for repair of cartilage than late or no treatment, with a concurrent decrease in the detrimental disturbance of cartilage metabolism which constituted a protective effect on the articulation