Cementless surface replacement arthroplasty of the shoulder. 5- to 10-year results with the Copeland mark-2 prosthesis.
(9/469)
Cementless surface replacement arthroplasty of the shoulder is designed to replace the damaged joint surfaces and restore normal anatomy with minimal resection of bone. We have used the Copeland shoulder arthroplasty for 14 years. Between 1986 and 2000, 285 surface replacement arthroplasties were implanted in our unit. The prosthesis has evolved during this time, but the principle of minimal bone resection has remained the same. Between 1990 and 1994, 103 Mark-2 prostheses were inserted into 94 patients (9 bilateral). The operations were carried out for the treatment of osteoarthritis, rheumatoid arthritis, avascular necrosis, instability arthropathy, post-traumatic arthropathy and cuff arthropathy. The mean follow-up was for 6.8 years (5 to 10). The best results were achieved in primary osteoarthritis, with Constant scores of 93.7% for total shoulder replacement and 73.5% for hemiarthroplasty. The poorest results were seen in patients with cuff arthropathy and post-traumatic arthropathy with adjusted Constant scores of 61.3% and 62.7%, respectively. Most patients (93.9%) considered their shoulder to be much better or better than before the operation. Of the 88 humeral implants available for radiological review, 61 (69.3%) showed no evidence of radiolucency, nor did 21 (35.6%) of the 59 glenoid prostheses. Three were definitely loose, and eight shoulders required revision (7.7%), two (1.9%) for primary loosening. The results of this series are comparable with those for stemmed prostheses with a similar follow-up and case mix. The cementless surface replacement arthroplasty diminishes the risk of complications involving the humeral shaft and periprosthetic fractures. Revision or arthrodesis can be undertaken easily since the bone stock has been maintained with no loss of length. (+info)
Sealing effect of hydroxyapatite coating on peri-implant migration of particles. An experimental study in dogs.
(10/469)
We have studied the beneficial effects of a hydroxyapatite (HA) coating on the prevention of the migration of wear debris along the implant-bone interface. We implanted a loaded HA-coated implant and a non-coated grit-blasted titanium alloy (Ti) implant in each distal femoral condyle of eight Labrador dogs. The test implant was surrounded by a gap communicating with the joint space and allowing access of joint fluid to the implant-bone interface. We injected polyethylene (PE) particles into the right knee three weeks after surgery and repeated this weekly for the following five weeks. The left knee received sham injections. The animals were killed eight weeks after surgery. Specimens from the implant-bone interface were examined under plain and polarised light. Only a few particles were found around HA-coated implants, but around Ti implants there was a large amount of particles. HA-coated implants had approximately 35% bone ingrowth, whereas Ti implants had virtually no bone ingrowth and were surrounded by a fibrous membrane. Our findings suggest that HA coating of implants is able to inhibit peri-implant migration of PE particles by creating a seal of tightly-bonded bone on the surface of the implant. (+info)
Effect of PMMA particles and movement on an implant interface in a canine model.
(11/469)
The pathogenesis of aseptic loosening of total joint prostheses is not clearly understood. Two features are associated with loosened prostheses, namely, particulate debris and movement of the implant. While numerous studies have evaluated the cellular response to particulate biomaterials, few have investigated the influence of movement of the implant on the biological response to particles. Our aim was therefore to test the hypothesis that excessive mechanical stimulation of the periprosthetic tissues induces an inflammatory response and that the addition of particulate biomaterials intensifies this. We allocated 66 adult Beagle dogs to four groups as follows: stable implants with (I) and without (II) particulate polymethylmethacrylate (PMMA) and moving implants with (III) and without (IV) particulate PMMA. They were then evaluated at 2, 4, 6, 12 and 24 weeks. The stable implants were well tolerated and a thin, fibrous membrane of connective tissue was observed. There was evidence of positive staining in some cells for interleukin-6 (IL-6). Addition of particulate PMMA around the stable implants resulted in an increase in the fibroblastic response and positive staining for IL-6 and tumour necrosis factor-alpha (TNF-alpha). By contrast, movement of the implant resulted in an immediate inflammatory response characterised by large numbers of histiocytes and cytokine staining for IL-1beta, TNF-alpha and IL-6. Introduction of particulate PMMA aggravated this response. Animals with particulate PMMA and movement of the implant have an intense inflammatory response associated with accelerated bone loss. Our results indicate that the initiation of the inflammatory response to biomaterial particles was much slower than that to gross mechanical instability. Furthermore, when there was both particulate debris and movement, there was an amplification of the adverse tissue response as evidenced by the presence of osteolysis and increases in the presence of inflammatory cells and their associated cytokines. (+info)
Excision of tumours of humerus and femur, with restoration by internal prostheses.
(12/469)
A personal experience is recounted of operations in cases of tumour involving the humerus or femur with restoration by endoprostheses. Twenty-four patients were treated in this way from 1950 to 1969 inclusive and have been followed up for between four and twenty-four years. The patients selected for treatment have presented chondrosarcoma (ten), so-called benign giant-cell tumour of bone, usually recurrent (nine), angiomatous osteolysis (two), seemingly single thyroid or renal metastasis (two), and ununited pathological fracture after irradiation of a tumour (one). Development of the prostheses from early beginnings is outlined. Some points in surgical management are referred to. The complications and results are recorded. (+info)
Revision total elbow replacement using the Souter-Strathclyde prosthesis.
(13/469)
The Souter-Strathclyde prosthesis was used in 52 evisions of total elbow replacements (TERs) between August 1986 and May 1997. Of these, 50, carried out in 45 patients, were prospectively followed for a mean of 53 months (14 to 139). The procedure produced reliable relief of pain, and the range of movement was preserved. There was a considerable incidence of adverse events associated with revision (30%), and 12 further procedures have been required. Nonetheless, a revision is the preferred salvage procedure for failed primary arthroplasty in the absence of sepsis. (+info)
Analysis of services available for total joint replacement surgery.
(14/469)
The use of a total joint replacement surgery has been growing in a manner which is poorly understood. This growth is more likely to be limited by saturation of the available medical services than by a limit to the number of people who could benefit from the treatment. Present indications are that services will be saturated in 1974 or 1975, after which 4600 extra people a year will go on to the waiting lists if demand continues as at present. Stability can then be achieved by either raising the clinical criteria for surgical treatment or making about 300 extra orthopaedic beds available each year, buffered from the demands of acute trauma admissions. (+info)
Medical devices; reclassification of the shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented prosthesis. Food and Drug Administration, HHS. Final rule.
(15/469)
The Food and Drug Administration (FDA) is announcing that it is reclassifying the shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented prosthesis intended to replace a shoulder joint from class III to class II (special controls). The agency is also announcing that it has issued an order in the form of a letter to the Orthopedic Surgical Manufacturers Association (OSMA) reclassifying the device. The special control that will apply is a guidance document entitled "Class II Special Controls Guidance: Shoulder Joint Metal/Polymer/Metal Nonconstrained or Semi-Constrained Porous-Coated Uncemented Prosthesis." The agency is classifying this device into class II because special controls, in addition to general controls, would provide reasonable assurance of the safety and effectiveness of the device, and there is sufficient information to establish special controls. (+info)
Which primary shoulder and elbow replacement? A review of the results of prostheses available in the UK.
(16/469)
To assist surgeons select a suitable prosthesis, we have undertaken a detailed review of all shoulder and elbow replacements currently marketed in the UK. Twenty shoulder and 8 elbow implants, manufactured by 16 companies, have been identified. Twelve of the shoulder and one of the elbow implants have been introduced or modified in the last 8 years and have no clinical results published in peer-reviewed journals. Only the Biomodular, Bipolar, Copeland, Isoelastic, Neer hemi, Neer II, Roper-Day and Select shoulders accounting for less than 40% of the UK shoulder market, possess published results. The Capitello-condylar, Coonrad-Morrey, GSB III, Kudo, Liverpool, Roper-Tuke and Souter-Strathclyde elbows all have published results. These account for over 95% of all UK elbow replacements. The implications of these findings in an era of evidence-based medicine is discussed. Reviewing the clinical results should be of primary importance in the selection of a suitable prosthesis. Implants with a proven long-term record must represent the 'gold standard'. New or modified implants should only be used if they are part of a properly conducted clinical trial. (+info)