We present the use of dynamic electromyographic analysis (DEMG) in the diagnosis of muscle patterning instability. DEMG’s were requested in 168 of 562 muscle patterning shoulders with suspected subclinical or clinically complex muscle patterning instability. An experienced neurophysiologist (blinded to the clinical findings and direction of instability) inserted dual-wire tungsten electrodes into pectoralis major, latissimus dorsi, infraspinatus and anterior deltoid. Muscle activity was recorded during rest, flexion, abduction, extension, and cross-body adduction. 5 investigations were abandoned. The timing and magnitude of muscle activity was noted and compared to the clinical diagnosis and direction of instability. DEMG identified a total of 204 abnormal muscle patterns in 163 shoulders. The examination was normal in 13 patients (8%). A single muscle was abnormal in 63 shoulders, 2 muscles in 55, 3 muscles in 9, and all 4 muscles in one shoulder. Over-activation of pectoralis major was identified in 58%, and latissimus dorsi in 70%, of shoulders with anterior instability. In posterior instability, latissimus dorsi was overactive in 76%, anterior deltoid in 14% and infraspinatus was under-active in 24%. Pectoralis major and Latissimus dorsi were both overactive in 38% of anterior, 29% of posterior and 38% of multidirectional instability. Abnormal muscle patterns were identified in 52 shoulders with subclinical muscle patterning. A further 98 shoulders had 134 clinically abnormal muscle patterns. These were confirmed by DEMG in 57 cases (sensitivity 43%), and DEMG’s were normal in 77 (specificity 43%). DEMG also identified 65 additional muscles as abnormal in the 98 clinically abnormal shoulders. DEMG performed by an experienced neurophysiologist provides additional information regarding abnormal muscle activation in selected complex or subtle cases of muscle patterning instability in which clinical examination has a low sensitivity and specificity.
All patients diagnosed with muscle patterning disorder received specilalist physical therapy using biofeedback. Symptomatic improvement or stability was achieved in 76% of patients with anterior instability but with no previous surgery, and in 53% of patients with previous surgery. Posterior instability was eliminated in 85% of cases.
In 1991 15% of the UK population that travelled abroad required medical assistance. We have been treating more patients with lower limb injuries requiring repatriation via aircraft. Recommendations from Airlines were unavailable. 357 Consultants replied to a questionnaire about transportation of patients with a lower limb injury wearing a plaster cast. There was no consensus on safe transportation of these patients. No scientific data is available on the dynamics of transportation of patients with lower limb trauma. In order to assess the safest method of transportation an experiment was conducted. Ethical committee approval was granted. Five volunteers wearing above leg plaster casts were placed in a decompression chamber. The effects on anterior compartment pressures, Doppler venous return, ambient pressure between plaster and skin were assessed in different positions with and without plasters being split. In the normal population we have shown a trebling of intracompartmental pressures from an average of under 10mmHg to 30mmHg. Intracompartmental pressures are more raised with 90 degrees of hip flexion rather than 45 degrees. We recommend patients be transferred with their legs at 45 degrees to the ground with a split plaster cast.
To devise an operative approach to the management of acute posterior fracture-dislocation of the shoulder which restores or retains normal proximal humeral anatomy and allows the early restoration of a complete, stable range of motion. Since 1996 we have treated four male patients (five shoulders) aged between 19 and 54 years at the time of first dislocation with autogenous iliac grafting of the anterior humeral head defect for acute and acuteon-chronic posterior dislocation of the shoulder. Two patients had epilepsy: one of these patients had bilateral dislocations. Two patients had motorbike RTAs. The deltopectoral approach with vertical division of the subscapularis tendon was used in all cases. The defects comprised 20– 25% of the volume of the humeral head at the equator after preparation for grafting. Grafts were fixed with compression screws. The subscapularis tendon was repaired anatomically. Active-assisted rehabilitation was started immediately, restricting external rotation to the neutral position for six weeks, thereafter allowing full rotation and elevation as comfort allowed. The patient with bilateral dislocations died of unrelated causes 18 months after surgery. He was reported to have had no further dislocations, complete pain free functional use of both shoulders and no complications of the procedure. The remaining three patients were reviewed at a minimum of 20 months after surgery (average 35 months). All grafts had incorporated. There was no graft collapse or boundary arthrosis. The absolute Constant scores were 85.1, 90.9, and 89.2; the subjective shoulder scores were 98%, 90%, and 99%; the Oxford rating scale for pain scores were 14 out of 60, 13 out of 60, and 14 out of 60; and the Oxford rating scale for instability scores were 14 out of 60, 15 out of 60 and 15 out of 60. There were no redislocations, or complications of the procedures. Posterior stability appears more dependant on surface arc of contact than on capsular integrity, in contrast to the anteriorly unstable shoulder. Restoration of the articular surface arc of contact by segmental autogenous grafting retains normal humeral anatomy, allows normal motion with excellent cuff function, and a return to normal daily activities. The procedure has been shown to be safe at a minimum of 20 months.
