to measure the total metal content in cell saver blood recovered during revision hip arthroplasty, to evaluate the efficacy of centrifuging and washing the recovered blood in reducing the metal content, to investigate whether transfusion of the salvaged blood resulted in a significant increase in the metal ion levels in the patients’ blood in the immediate post-operative period.
We report 17 patients (20 hips) in whom metal-on-metal resurfacing had been performed and who presented with various symptoms and a soft-tissue mass which we termed a pseudotumour. Each patient underwent plain radiography and in some, CT, MRI and ultrasonography were also performed. In addition, histological examination of available samples was undertaken. All the patients were women and their presentation was variable. The most common symptom was discomfort in the region of the hip. Other symptoms included spontaneous dislocation, nerve palsy, a noticeable mass or a rash. The common histological features were extensive necrosis and lymphocytic infiltration. To date, 13 of the 20 hips have required revision to a conventional hip replacement. Two are awaiting revision. We estimate that approximately 1% of patients who have a metal-on-metal resurfacing develop a pseudotumour within five years. The cause is unknown and is probably multifactorial. There may be a toxic reaction to an excess of particulate metal wear debris or a hypersensitivity reaction to a normal amount of metal debris. We are concerned that with time the incidence of these pseudotumours may increase. Further investigation is required to define their cause.
We report the clinical, radiographic and histologic features of these cases.
There were no infections in this series. Three subjects required revision surgery.
This study suggests that resurfacing arthoplasty can also induce a local hypersensitivity reaction in response to metal wear debris. It therefore raises new concerns regarding the long-term safety of this procedure.
The creep and wear behaviour of highly cross-linked polyethylene and standard polyethylene liners were examined in a prospective, double-blind randomised, controlled trial using radiostereometric analysis. We randomised 54 patients to receive hip replacements with either highly cross-linked polyethylene or standard liners and determined the three-dimensional penetration of the liners over three years. After three years the mean total penetration was 0.35 mm (SD 0.14) for the highly cross-linked polyethylene group and 0.45 mm (SD 0.19) for the standard group. The difference was statistically significant (p = 0.0184). From the pattern of penetration it was possible to discriminate creep from wear. Most (95%) of the creep occurred within six months of implantation and nearly all within the first year. There was no difference in the mean degree of creep between the two types of polyethylene (highly cross-linked polyethylene 0.26 mm, SD 0.17; standard 0.27 mm, SD 0.2; p = 0.83). There was, however, a significant difference (p = 0.012) in the mean wear rate (highly cross-linked polyethylene 0.03 mm/yr, SD 0.06; standard 0.07 mm/yr, SD 0.05). Creep and wear occurred in significantly different directions (p = 0.01); creep was predominantly proximal whereas wear was anterior, proximal and medial. We conclude that penetration in the first six months is creep-dominated, but after one year virtually all penetration is due to wear. Highly cross-linked polyethylene has a 60% lower rate of wear than standard polyethylene and therefore will probably perform better in the long term.
The Charnley Elite femoral component was first introduced in 1992 as a new design variant of the original Charnley femoral component (De Puy, Leeds, UK) with modified neck and stem geometry. The original component had undergone few changes in nearly forty years and has excellent long-term results. Early migration of the new stem design was determined by Roentgen Stereophotogrammetric Analysis (RSA)1. Rapid early migration of a component relative to the bone, measured by RSA, is predictive of subsequent aseptic loosening for a number of femoral stems. As there was rapid early migration and rotation of the Charnley Elite stem, we predicted that the long-term results would be poor. An outcome assessment is indicated as stems of this type are still being implanted. One hundred Charnley Elite stems, implanted in our centre between 1994 and 1997 were included in a prospective, cross-sectional follow-up study. Outcome measures include validated clinical scores (Charnley hip score, Harris hip score and Oxford hip score) and radiological scores (Gruen classification) as well as revision rates over the past 10 years. The clinical follow-up supports the RSA predictions of early failure of the Charnley Elite femoral stem.
Patients had improvement of pain, posture, hip instability, walking ability and limb length discrepancy. The median lengthening of the femur was 3 cm (2–5). The mechanical axis was realigned in all patients. All patients were satisfied with the outcome. Planned secondary contra lateral epiphyseodesis was required to equalise leg length in 2 patients. Complications included a stiff knee (1) that required a Judet quadricepsplasty, premature consolidation (1) that required reosteotomy and knee subluxation (1) that required cross knee stabilisation.
We changed our pin tract care practice from 1996. We had a significant decrease in pin tract infections since then (p<
0.0001). We also found that using Ilizarov wires had significantly less infections than with half pins used with monolateral fixators (p<
0.0001; linear trend, p= 0.0338). There were 48 patients that required hospital admissions for IV antibiotics. and of these 10 patients required debridement. There were no residual long lasting infections or chronic osteomyelitis.
Arthroscopic procedures may be associated with considerable pain in the first 24 hours. Intra-articular bupi-vacaine provides good analgesia but is short lasting. Intra-articular morphine has been shown to prolong postoperative analgesia in knee and ankle arthroscopy. The aim of this study is to assess the safety and analgesic effect of intra-articular morphine following day case wrist arthroscopy. Ethical approval was firstly obtained. 31 patients were randomly assigned to one of 2 groups in a double blind clinical study. Group 1 received 5ml of 0.5% bupi-vacaine intra-articularly with 5mg of morphine subcutaneously. Group 2 received 5ml of 0.5% bupivacaine and 5mg of morphine intra-articularly. There were 15 patients (mean age 41.2 years) in group 1, and 16 patients (mean age 38.9 years) in group 2. Postoperatively pain was assessed using a 100mm visual analogue pain scale (VAPS) at 1, 2, 6 and 24 hours. Analgesia requirements were recorded at these times post operatively. The presence of nausea, vomiting, other complications and patient satisfaction were recorded. Visual analogue pain scores did not show any significant difference between the groups at 1, 2, 6 and 24 hours. Supplementary analgesic consumption over the 24 hour period was slightly greater in group 1 than in group 2. None of the patients who had intra-articular Morphine had vomiting nor any other complications and did not require anti-emetics. Most patients in either group were satisfied with the level of postoperative analgesia. Intra-articular bupivacaine with or with out morphine provides adequate postoperative pain relief following wrist arthroscopy. There seems to be little difference between the two methods studied.