Introduction: Between 1987 and 1997 we implanted 319 primary hybrid total hip arthroplasties in 289 patients using the ‘Plasmacup’ (B. Braun Ltd, Sheffield) with a conventional metal on polyethylene articulation. We have observed a high revision rate with this implant recently and therefore undertook a clinical review of this cohort.

Patients and Methods: The indications for surgery were osteoarthritis (223), secondary arthritis (83), inflammatory arthritis (10), and others (3). 17 patients have died and 20 have been lost to follow up. Survival analysis was calculated using implant failure defined as revision (including liner exchange), and includes the censored patients outlined above. Assessment of complications in surviving implants was made using AP radiographs of the hip.

Results: The cup survival rate (Kaplan-Meier method) was 91% at 10 years (95%CI ± 4%) and 67% at 13 years (95%CI +/−9%). The stem survival rate was 96% at 10 years (95%CI +/−3%) and 87% at 13 years (95%CI +/−7%). The median wear in cup revisions for osteolysis was 2.4mm (IQR 1.0–3.2mm), and the median wear in surviving cups was 1.3 mm (IQR 0.8 1.9mm), and was an independent predictor of failure (Cox: p=0.001). There have been 57 revisions (35 cup only, 18 cup and stem, 4 stem only). Indications for revision were osteolysis or loosening (34), wear (18), and infection (5). In surviving cups (214), 29 have expansile acetabular osteolysis and 8 have linear osteolysis. In surviving stems (244), 14 have expansile osteolysis and 23 have linear osteolysis.

Conclusions: There is a high late failure rate of the plasma cup using a conventional metal on polyethylene articulation. Patients with this implant/bearing combination should be closely monitored, particularly after 10 years.

Introduction

Osteochondritis dissecans (OCD) is a localised disorder of subchondral bone and the overlying articular cartilage. The most commonly used classification systems involve arthroscopy and MRI.

Aim

To investigate the correlation between arthroscopic and MR findings in patients with OCD of the talus.

Methods

16 ankles in 14 patients with radiographically proven OCD were reviewed. Nine were male and five female. Mean age was 35yrs (range 18–64yrs). The lesions were staged independently using the Guhl1 arthroscopic and Dipaola2 MR classification systems.

Results

Arthroscopically there were eight stable and eight unstable lesions. Of the eight stable lesions, MRI staged five as stable and three as unstable. Of the eight unstable lesions, MRI staged six as unstable and two as stable. This gives a sensitivity of diagnosing unstable lesions as 0.75, with a specificity of 0.63.

Conclusions

This small study demonstrates that MR scans may have some limitations in classifying OCD lesions of the talus. Possible explanations are discussed. We propose that MRI findings, of OCD of the talus, should not be taken in isolation, but correlated with the patients symptoms and signs to avoid unnecessary arthroscopy.

Introduction: We performed a prospective double blind randomised clinical trial to measure the effect of pre-operative infiltration of local anaesthetic around arthroscopy wounds compared to post-operative infiltration on post operative pain relief. The underlying clinical principle is for therapeutic intervention to be made in advance of the pain rather than as a reaction to it.

Methods: 36 patients undergoing daycase unilateral knee arthroscopy between October 2000 and March 2001 were studied. The pre-operative group had 10ml 0.25% bupivicaine infiltrated around the arthroscopy portal site following induction of general anaesthesia (G.A.), the postoperative group received 10ml 0.25% bupivicaine after the procedure but before reversal of the G.A. Pain was assessed using a 10cm Visual Analogue Score (VAS) at pre-operative, 1, 2 and 24 hours post operative. At each assessment the patients were blinded to the previous scores that they had submitted. Oral analgesic use in the post-operative 24 hours was also recorded.

Results: There were 18 patients in each group. The mean Visual Analogue Pain Scores (VAS) were lower in the post-op group (1.3) compared to the pre-op group (1.58) at pre-operative assessment. However this difference was not statistically significant (p=0.5607).

At 1 hour post-op the mean VAS in the post-op group was 1.58 and in the pre-op group 2.59. This difference was not statistically significant (p=0.18).

The mean VAS at 2 hours post-op in the pre-op, group was 1.76 compared to 1.82 in the post-op group. This difference was not statistically significant (p=0.9932).

At 24 hours the pre-op group had a lower mean VAS (2.25) than the post-op group (2.4). This difference was however not statistically significant (p=0.7418).

Analysis of the post-operative analgesia requirement in both groups failed no reveal a statistically significant difference (p=0.3965).

Conclusion: In daycase knee arthroscopy under general anaesthesia there is no beneficial role in the use of pre-emptive local anaesthetic infiltration around the arthroscopy portal sites as compared to post-operative infiltration.