Metal-metal surface replacement (MoMSRA) continues to be used in young women. Systemic metal ion release and its effects cause concern. Do metal ions crossing the placenta in pregnant women have potential mutagenic effects? The hypothesis is that metal ions pass freely through the placenta and there is no difference in maternal and cord metal levels. This is a controlled cross-sectional study of women with MoMSRA. (n = 25, 3 bilateral, mean age 32 years, time from implantation to delivery 60 months). The control group consisted of 24 subjects, mean age 31 years, with no metallic implant and not receiving cobalt/chromium supplements. No patient was known to have renal failure. Whole blood specimens were obtained before delivery and before any infusion or transfusion, and cord blood specimens immediately after delivery.Introduction
Methods
Large diameter metal-on-metal hip arthroplasty (LDMMTHA) provides benefits of reduced dislocation rates and low wear. The use of modular systems allows better restoration of hip biomechanics. There have been reports of modular LDMMTHAs with tapered sleeves generating excessively high metal ions, due to possible mismatch between the titanium stem and the cobalt-chrome sleeve and the dual Morse tapers involved. We evaluated metal ion levels in LDMMTHA patients with and without a cobalt-chrome (CoCr) tapered sleeve. A cross-sectional series of 91 patients with proximal porous titanium alloy stem LDMMTHA with identical design CoCr bearings, attending a 1 to 2-year review were assessed with routine clinical and radiographic examinations, hip scores and metal ion analysis. Of these 65 had a single Morse taper between monoblock CoCr heads and the stems. Twentysix had a tapered cobalt-chrome sleeve in addition, with the resultant dual taper. Mean bearing diameter was 46 mm in both groups and mean age was 58 years in the monoblocks and 66 years in the tapered sleeve group.Introduction
Methods
Modern metal-on-metal bearing resurfacings have been in use for nearly two decades. Local and systemic metal ion exposure continues to cause concern. We could not find a prospective metal ion study in such patients with a 10-year follow-up. This is the first ten year prospective study of metal ion levels in blood and their release in urine following hybrid fixed metal-on-metal surface arthroplasty. Twenty six patients were included in an ongoing longitudinal metal ion study of patients with unilateral metal-on-metal hip resurfacings. Three of them were excluded due to subsequent contralateral resurfacing and one has relocated abroad. Cobalt and chromium levels were assessed in 12 hour urine collections before and periodically after operation (5 days to 10 years) using high resolution plasma mass spectrometry. Mean age at operation was 53 years and mean BMI 27.9.Introduction
Methods
This is a retrospective review of the incidence of deep venous thrombosis (DVT) in 679 consecutive unilateral primary hip arthroplasty procedures performed between January 2007 and December 2010 managed with no anticoagulants. Mean age at operation was 58 years. Mean BMI was 26. The prophylaxis regimen included hypotensive epidural anesthesia, compression stockings, intermittent calf compression, early mobilization and an antiplatelet agent. 562 hybrid hip resurfacing procedures and 117 uncemented THRs, all performed through a posterior incision were included. Doppler ultrasound screening for DVT was performed in all patients between the fourth and sixth post-operative days. Patients were reviewed clinicoradiologically 6 to 10 weeks after operation and with a postal questionnaire at the end of 12 weeks to detect symptomatic VTE incidence following discharge. 14 patients with pre-existent VTE, coagulation disorders or cardiac problems requiring anticoagulant usage were excluded.Introduction
Methods
High early failure rates have been reported with certain metal-metal surface arthroplasties and good results have been reported with others. This is a minimum 10-year review of the first 1000 consecutive resurfacings including all ages and diagnoses from one centre. The first 1000 surface arthroplasties (892 patients) were followed-up with postal questionnaires. Of these the first 402 hips (350 patients) were also invited for a clinico-radiological review. 54 patients (63 hips) died 6.7 years (0.7–12.6) later due to unrelated causes. Mean follow-up is 12.2 years (range 10.8–13.7). Radiographs were assessed independently by a senior musculoskeletal radiologist.Introduction
Methods
Wear and corrosion of metal-on-metal (MM) bearings releases (a) soluble metal ions which collect locally and pass into the systemic circulation and (b) insoluble particles which undergo local deposition and lymphoreticular dissemination. Debris-related failures from osteolysis, metallosis and pseudotumours warrants revision of these MM bearing devices to non-MM bearing arthroplasties with the expectation that both the systemic and local effects will be reversed with time since the source of metal ion release is removed. The purpose of the present study is to determine (a) whether metal ion levels in blood and urine decrease after revision of a MM bearing arthroplasty to a non-MM bearing device and (b) the rate at which this decrease is effected. Blood and urine levels of cobalt and chromium ions are studied prospectively over two years in 15 patients whose MM resurfacings were revised to cross-linked polyethylene containing total hip replacements (THRs). Specimen collection was started before and periodically after the revision at 2, 4 and 6 days and 2 months, 6, 12 and 24 months after operation. None of the patients had other MM devices or compromised renal function.Introduction
Methods
Hip simulator studies show that metal-on-metal bearing wear can be reduced by reducing the diametral clearance of the bearing. We present the six-year follow-up results of a prospective clinico-radiological and metal ion study in patients with a low clearance metal-metal surface arthroplasty. The results are compared to published results of similar design bearings with conventional clearance. Twentysix male patients (mean age 55 years, mean BMI 26) who received a 50 mm bearing resurfacing (radial clearance 50μm) were included in an ongoing clinico-radiological and metal ion study. Urine/blood specimens were obtained before and periodically after hip resurfacing. Patients were also assessed with Oxford Hip Scores and Harris Hip Score questionnaires. Two hips were excluded during follow-up, one for revision and another for contralateral hip arthroplasty.Introduction
Methods
The results of the Birmingham Hip Resurfacing (BHR) device in several series reveal that the predominant mode of failure is femoral neck fracture or femoral head collapse and that careful patient selection and precise operative technique are vital to the success of this procedure. In this report we consider the results of BHR in patients with severe arthritis secondary to femoral head AVN. This was a single-surgeon consecutive series of BHRs with a minimum follow-up of 5 years. Fifty-nine patients with Ficat-Arlet grade III or IV femoral head AVN (66 hips) and treated with BHRs at a mean age of 43.9 years (range 19 to 67.7 years) were followed up for 5.4 to 9.6 years (mean 7.1 years). No patient died and none was lost to follow-up. Revision for any reason was the end-point and unrevised patients were assessed with Oxford hip scores. They were also reviewed clinically and with AP and lateral radiographs.Introduction
Methods
Large diameter metal-metal total hip replacements (MM THRs) offer the advantages of low wear and low dislocation risk and are being increasingly used in high-demand patients whose bone quality rules out the possibility of a hip resurfacing. However suggests that large headed MM devices may result in greater systemic metal exposure compared to small diameter bearings. This raises fresh concerns of elevated systemic metal levels. Whole blood concentrations and daily output of cobalt and chromium in 28 patients with unilateral large diameter MM THRs (42 to 54mm bearings) were studied at 1-year follow-up. These were compared with the whole blood levels in 20 patients at 1 year and daily output of metal ions in 28 patients with 28mm MM THRs at 1 to 3 years. Both bearings are made of high carbon cobalt-chrome alloy, the larger bearing is as-cast alloy and the smaller is wrought alloy. High resolution inductively coupled plasma mass spectrometry was used for analysis. None of the patients had other metal devices or compromised renal function. They had either a cemented polished tapered stainless steel stem or a cementless porous ingrowth titanium alloy stem.Introduction
Methods
Secondary osteoarthritis in a dysplastic hip is a surgical challenge. Severe leg length discrepancies and torsional deformities add to the problem of inadequate bony support available for the socket. Furthermore, many of these patients are young and wish to remain active, thereby jeopardising the long-term survival of any arthroplasty device. For such severely dysplastic hips, the Birmingham Hip Resurfacing (BHR) device provides the option of a dysplasia component, a hydroxyapatite-coated porous uncemented socket with two lugs to engage neutralisation screws for supplementary fixation into the solid bone of the ilium more medially. The gap between the superolateral surface of the socket component and the false acetabulum is filled with impacted bone graft. One hundred and thirteen consecutive dysplasia BHRs performed by the senior author (DJWM) for the treatment of severely arthritic hips with Crowe grade II and III dysplasia between 1997 and 2000 have been reviewed at a minimum five year follow-up. There were 106 patients (59M and 47F). Eighty of the 113 hips were old CDH or DDH, 29 were destructive primary or secondary arthritis with wandering acetabulae and four were old fracture dislocations of the hip. Mean age at operation was 47.5 years (range 21 to 68 years – thirty-six men and forty-four women were below the age of 55 years). There were two failures (1.8%) out of the 113 hips at a mean follow-up of 6.5 years (range 5 to 8.3 years). One hip failed with a femoral neck fracture nine days after the operation and another failed due to deep infection at 3.3 years.Introduction
Methods and results
