Study design: To investigate the effects of muscle atrophy on back muscle fatigue:

Objective: To assess fibre type atrophy in patients undergoing surgery for pro-lapsed lumbar intervertebral disc, and to determine its effect upon EMG measures of fatigue.

Methods: Intra-operative biopsies were obtained from the erector spinae muscles of patients undergoing microdiscectomy. Mean fibre area of type I and II fibres were determined after myosin ATPase staining. Prior to surgery, EMG activity of the erector spinae muscles was recorded bilaterally at T10 and L3 whilst subjects performed the Biering-Sorensen fatigue test. Power spectral analysis indicated the initial median frequency and its rate of decline (median frequency gradient) at each recording site. Fibre type area was compared with the median frequency measures.

Subjects: 34 subjects (20 male) with intervertebral disc prolapse.

Results: Mean fibre area of type I and II fibres was 5890 ± 1947μm² and 3461 ± 1946μm² in men, and 5144 ± 1692μm² and 1945 ± 1039μm² in women, indicating marked type II fibre atrophy. Type II MFA was positively correlated with initial median frequency at L3 on the operated side (R=0.445) and negatively correlated with the maximum median frequency gradient of the four recording sites (R= −0.430).

Conclusion: Type II fibre atrophy influences EMG measures of fatigue. The decrease in initial median frequency with type II fibre atrophy probably reflects a reduced conduction velocity in these small fibres. The less negative median frequency gradient with decreased type II fibre size indicates a lower rate of fatigue which may be explained by an increased contribution to force generation from type I fibres which occupy a greater proportion of the muscle.

Introduction and Aims: Cold therapy is known to reduce pain and swelling after surgical procedures on the knee. We hypothesised that if cold therapy is started earlier, then there would be a reduction in pain and swelling in patients undergoing arthroscopic anterior cruciate ligament [ACL] reconstruction.

Method: We prospectively randomised 40 patients undergoing arthroscopic ACL reconstruction with hamstring autograft, to receive either room temperature [19° C] or cold [4° C] arthroscopy irrigation fluid. Patients were then assessed over the following seven days, with regard to pain [measured on a visual analogue scale], and swelling [measured with limb girth at four points around the knee].

Results: Pain scores were consistently reduced in the cold fluid group compared to the room temperature group throughout the post-operative period, and this difference was significant [p< =0.05] from six hours until seven days post-operatively. At day seven, the swelling measured at 5cm below the joint and 5cm above the joint were significantly lower in the cold group compared with the room temperature group. Drainage from the intra-articular drain was significantly lower in the cold group.

Conclusion: The use of cold irrigation fluid is a simple and safe measure by which pain and swelling (at day 7) can be reduced in the early post-operative period for arthroscopic ACL reconstruction.

Introduction Cold therapy is known to reduce pain and swelling after surgical procedures on the knee. We hypothesised that if cold therapy is started earlier, then there would be a reduction in pain and swelling in patients undergoing arthroscopic anterior cruciate ligament (ACL) reconstruction

Methods We prospectively randomised 40 patients undergoing arthroscopic ACL reconstruction with hamstring autograft, to receive either room temperature (19°C) or cold (4°C) arthroscopy irrigation fluid.Patients were then assessed over the following 7 days, with regard to pain (measured on a visual analogue scale), and swelling (measured with limb girth at 4 points around the knee).

Results Pain scores were consistently reduced in the cold fluid group compared to the room temperature group throughout the post operative period, and this difference was significant (p< =0.05) from 6 hours until 7 days post-operatively

At day 7 the swelling measured at 5cm below the joint and 5cm above the joint were significantly lower in the cold group compared with the room temperature group.

Drainage from the intra-articular drain was significantly lower in the cold group.

Conclusion The use of cold irrigation fluid is a simple and safe measure by which pain and swelling (at day 7), can be reduced in the early post-operative period for arthroscopic ACL reconstruction.