Biomedical subjects
Publications and source records attributed to P D McCann.
Injuries to the acromioclavicular joint are common, and most can be treated nonoperatively. Appropriate treatment depends on accurate diagnosis and appreciation of the classification of these various injuries. Descriptions of the commoner acromioclavicular joint injuries, details of the nonoperative treatment, and indications for surgical treatment are reviewed.
The differentiation of cervical radiculitis from primary shoulder disease at times can be very difficult owing to the close anatomic proximity of the neck and shoulder, overlapping symptoms, and similar patient groups affected by these disorders. A thorough history and detailed physical examination will, in most cases, identify the cervical spine or the shoulder as the primary source of the disease. Radiographic and electrodiagnostic tests and selective anesthetic injections can be used to confirm the diagnosis and thereby indicate appropriate treatment. Patients with concomitant disease of the shoulder and cervical spine may present a considerable diagnostic and therapeutic challenge. Treatment of these patients should be directed at the site of primary disease. Successful results can be achieved after accurate diagnosis and proper treatment.
Fourteen patients with a posterior-stabilized prosthesis in one knee and a posterior cruciate-retaining prosthesis in the contralateral knee and both scoring good or excellent on the Hospital for Special Surgery (HSS) knee scale were evaluated by isokinetic muscle testing and comprehensive gait analysis at a mean follow-up of 98 months after arthroplasty. The average HSS knee score (93 points) and the average Knee Society score (94 points) were the same for the cruciate-retaining and posterior-stabilized knees. No differences were noted between the cruciate-retaining and the posterior stabilized knees with respect to isokinetic muscle testing parameters (peak torque, endurance, angle of peak torque, and torque acceleration energy) for both quadriceps and hamstrings. No significant differences were found between the cruciate-retaining and the posterior-stabilized knees with regard to gait parameters, knee range of motion, and electromyographic waveforms during level walking and stair climbing. Cruciate-retaining and posterior-stabilized total knee prostheses perform equally well during level gait and stair climbing.
Sixteen patients implanted with a posterior-stabilized prosthesis (Insall-Burstein PS II, Zimmer, Warsaw, IN) and 32 age-matched control subjects were evaluated by isokinetic muscle testing and comprehensive gait analysis at a mean 46 months following the index arthroplasty. The contralateral knee was normal in 13 patients and an asymptomatic total knee arthroplasty in 3 patients. No significant differences (P > .05) were found between the study and control groups in spatiotemporal gait parameters nor were there isokinetic strength deficits. A prolonged firing of the vastus medialis was observed in some patients. Knee range of motion during level walking and stair descent was decreased significantly (P < .05) in the study group. There was no significant difference for knee range of motion between the study and control groups during stair ascent. Spatiotemporal gait parameters in the total knee arthroplasty patients show no significant differences from the control subject at nearly 4 years after surgery. However, other gait abnormalities are present and cannot be accounted for on the basis of muscle weakness, abnormal phasic muscle activity, or inadequate knee range of motion. With reference to historic control subjects, the persistent gait abnormalities of patients implanted with posterior-stabilized prostheses (posterior cruciate substituting) are comparable to those of patients implanted with cruciate-retaining prostheses and superior to cruciate-sacrificing prostheses.
Shoulder pain is a common complaint amongst tennis players. The anatomy of the shoulder girdle is complex and defining the exact pathology that accounts for shoulder pain in tennis players can be difficult. Impingement syndrome and glenohumeral instability are the 2 most common causes of shoulder pain in tennis players. Tennis players with impingement syndrome typically present with pain, especially during overhead strokes and serves. The impingement test helps to confirm the diagnosis. Treatment focuses on restoring any motion and strength deficits and anterior acromioplasty with repair of rotator cuff tears for patients who do not respond to nonoperative care. Tennis players with instability present with pain and a sensation of shoulder 'slipping'. Treatment emphasises rotator cuff and scapular muscle strengthening and surgical stabilisation of the capsulo-labral complex for patients who fail a rehabilitation programme. Prevention of injury in tennis players depends on maintaining flexibility, strength and synchrony among the glenohumeral and scapular muscles.
An athletic patient presented with a nontraumatic peroneal neuropathy that failed to resolve after a period of rest. A magnetic resonance image (MRI) showed a multilobulated mass in the course of the common peroneal nerve consistent with a plexiform neurofibroma. Surgical exploration revealed a mass, which coursed from the midthigh to the fibular neck, that was intimately involved with the fibers of the nerve bundle and had cystic degeneration with vesicles along its length. The authors recommend MRI as highly accurate in diagnosing unusual causes of peroneal neuropathy.
Equinovarus is the most common residual deformity of the lower extremity in patients who have sustained intracranial injury. Appreciation of the pathophysiology of the deformity aids in surgical management of selected cases. Gait analysis is a valuable tool for preoperative management. Three case reports illustrate the principles of surgical treatment.
The role of shoulder muscles during passive, active, and resistive phases of shoulder rehabilitation exercises was investigated in ten normal subjects with no history of shoulder pathology. Using the scapular plane as a reference, three-dimensional motion of the shoulder was recorded with a computer-aided motion analysis system (VICON) to determine total shoulder elevation. Simultaneously, electromyographic data were acquired on nine shoulder muscles while performing the three phases of shoulder rehabilitation exercises as described by Neer. Fine wire intramuscular electrodes were placed in the following muscles: trapezius, serratus anterior, deltoid (anterior, middle, and posterior separately), supraspinatus, infraspinatus, biceps, and latissimus dorsi. Phase I (passive) exercises performed in the supine position showed the least electromyography (EMG) activity. There was a gradation of EMG activity as one progressed from Phase I (passive) to Phase II (active) to Phase III (resistive) shoulder exercises. Isometric exercises and Phase III resistive exercises showed high levels of activity in the rotator cuff and deltoid muscles. Supine Phase I exercises should be considered in the early postoperative period after shoulder surgery to achieve maximum motion while minimizing shoulder muscle activity. Progression to Phase II and Phase III exercises may proceed as soft tissue and bony healing permit. Phase III exercises performed with an elastic band should provide a satisfactory method to strengthen these muscles.
We performed a comprehensive analysis of the relationships between histologic indices in the iliac crest (cancellous bone volume, trabecular structural indices, cortical width, and core width) and bone density in the spine, hip, and wrist in 81 patients with various metabolic bone diseases including osteoporosis, osteomalacia, hyperparathyroidism, and Paget's disease. In the whole group, all of the histologic indices correlated significantly with bone mineral density (BMD) of the spine and the three regions of the hip (r = 0.28-0.73), with the exception of cortical width which correlated with the hip but not the spine (r = 0.21). There was no relationship between the histologic variables and either the distal or proximal radius. When the osteoporotic subgroup was considered separately, the relationships between BMD and both cancellous bone volume and the structural indices (trabecular number, separation, and thickness) were lost. In contrast, cortical width correlated more strongly with both spine and hip BMD. The relationship between core width and the spine was lost but persisted in the hip region. In female osteoporotic patients alone, only cortical width remained significantly correlated with spine or hip BMD. We conclude that the relationships between bone densities in the axial and peripheral regions and histomorphometric variables in iliac crest are not constant. In addition, cancellous bone volume and the trabecular structural indices relate well to noninvasive axial BMD measurements only in a heterogenous group with a large variance in both parameters. In the more homogeneous group with osteoporosis, cortical width appears to be a more powerful predictor of BMD at the important sites of osteoporotic fracture.
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Brachial plexus injuries present in certain consistent patterns. Learning the overall brachial plexus anatomy--with an emphasis on the common sites of injury--can facilitate localization, which is essential for diagnosis and formulation of an appropriate treatment plan.
The course of the suprascapular nerve and its distance from fixed scapular landmarks were measured in 90 cadaveric shoulders. In an additional 15 cadavers, three pins were passed at various angles in a general anterior-posterior direction through the middle of the glenoid neck just inferior and lateral to the base of the coracoid process. The distance between the exit site on the posterior glenoid neck and the suprascapular nerve at the base of the scapular spine was recorded for each pin. Inferiorly directed pins were the furthest from the suprascapular nerve and averaged 16 mm. On the basis of these data, a relative safe zone is described in the posterior glenoid neck. Knowledge of the anatomic course of the suprascapular nerve may aid the physician in the diagnosis and treatment of suprascapular neuropathies. Appreciation of the safe zone may help the shoulder surgeon avoid iatrogenic injury to the suprascapular nerve during arthroscopic Bankart procedures and other open surgical procedures requiring dissection of the posterior glenoid neck.
Unicameral bone cysts are rarely observed in the foot. A histologically proven unicameral bone cyst occurred in the talus of a three-year-old boy. Six additional cases in the world literature are cited to illustrate the therapeutic and diagnostic problems encountered with this lesion.
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Twenty-three tennis players with a symptomatic full-thickness rotator cuff tear underwent anterior acromioplasty and rotator cuff repair. There were 8 small tears (less than 1 cm), 5 moderate tears (1 to 3 cm), 2 large tears (3 to 5 cm), and 8 massive tears (greater than 5 cm). The dominant shoulder was involved in all patients and all were unable to play tennis before surgery. Eleven patients experienced a traumatic event that caused an injury, 6 while playing tennis, and 12 patients had a gradual onset of symptoms. At average follow-up of 42 months, 19 patients (83%) achieved a good result, were pain-free, and were able to play tennis at their presymptomatic competitive level. Three patients (13%), all with massive tears, had a satisfactory result and were able to play tennis, although at a lower competitive level secondary to weakness. One patient (4%), who also had a massive tear, had an unsatisfactory result and was unable to play tennis.
Forty-four patients, ranging in age from 17 to 57 years (average, 32), were evaluated an average of 4 years (range, 2 to 9) after surgical reconstruction for Allman-Tossy Grade III acromioclavicular dislocations. Twenty-seven patients underwent repair for acute injuries (< 3 weeks after injury) and 17 patients underwent reconstructions for chronic injuries (> 3 weeks). Coracoclavicular fixation with heavy nonabsorbable sutures was used to correct superior displacement in all cases. In addition, transfer of the coracoacromial ligament to the distal clavicle was performed in 15 of the 27 early repairs and 17 of the 17 late reconstructions. Overall, 26 of 27 (96%) early repairs and 13 of 17 (77%) late reconstructions achieved satisfactory results. There was a trend for better results and return to sports or heavy labor with early repairs; however, this was not statistically significant (P = 0.065). When the results of early repairs were compared with those of late reconstructions performed more than 3 months after injury, the results of the shoulders undergoing early repair were significantly better (P < 0.01). Overall, 39 of 44 (89%) patients achieved a satisfactory result. Surgical reconstruction for acromioclavicular dislocation provides reliable results including use of the arm for sports or repetitive work.