Instability after total elbow arthroplasty.

Resurfacing total elbow arthroplasty is occasionally unstable. Instability may be related to insufficiency of the ligaments or improper tensioning and implant positioning at the time of surgery. Ligament reconstruction has produced mixed results; however, attempts to reconstruct the ligaments are probably worthwhile because conversion of a freshly cemented resurfacing implant to a semiconstrained hinge is very challenging.

Preoperative arthroscopic assessment of fractures about the shoulder.

Soft tissue lesions in fractures about the shoulder are not completely defined by conventional imaging procedures. The purpose of the present study was to arthroscopically determine the soft-tissue pathology of the labrum, capsuloligamentous, and rotator cuff structures associated with fractures of the proximal humerus and/or scapula and to correlate them to the fracture type. In a series of 80 fractures (52 proximal humeral fractures, 20 fracture-dislocations, 8 glenoid or scapular fractures) arthroscopy was performed through a posterior approach under general anesthesia. Arthroscopy revealed significant numbers of labral, capsuloligamentous, and rotator cuff lesions, as well as cartilage damage not identified by clinical examination or preoperative imaging. Fracture dislocations (Neer type VI) and more benign fractures of the two-part variety are frequently associated with labral lesions (in 56% and 31%, respectively). This data suggest that it is important not to underestimate soft-tissue pathology in fractures that seem radiologically relatively harmless. Arthroscopic assessment in shoulder fractures is shown to be a useful tool in completely understanding the extent of the injury.

The stenosis ratio: a new tool for the diagnosis of degenerative spinal stenosis.

CLINICAL RELEVANCE: Low back pain from lumbar spinal stenosis is a significant source of morbidity, especially among the elderly population. Accurate diagnosis is imperative for effective treatment to be initiated. This paper presents a quantitative method for the evaluation of spinal stenosis that, when used in conjunction with CT and MRI, may greatly aid the clinician in the diagnosis of this debilitating condition. OBJECTIVE: Precise clinical tools for the diagnosis of spinal stenosis are severely lacking. Low back pain and dysfunction derived from lumbar spinal stenosis is a significant source of morbidity, especially among the elderly. Despite its importance, there has been little progress made towards establishing valid, quantitative criteria for the diagnosis of spinal stenosis. We present a new quantitative tool for the diagnosis of lumbar stenosis, the Stenosis Ratio (SR). METHODS: CT scans and MRI scans of 43 patients presenting with clinico-radiographic evidence of lumbar stenosis were used. The patient group consisted of 13 males and 30 females between the ages 49 and 82 with average age of 67. CT and MRI/scans of 43 patients were digitized and computer analyzed. Measurements of SR, defined as the ratio of the cross-sectional dural area of the motion segment to that of the stable segment, were established for L3-L4, L4-L5 and L5-S1 stenotic levels and compared to SR values for a non-stenotic (internal control) level, L2-L3. RESULTS: The L4-L5 level had the lowest SR value of 0.71, followed by 0.74 at L3-L4, and 0.87 at L5-S1. Ninety-five percent confidence intervals of (0.66, 0.81), (0.62, 0.81), and (0.73, 1.00) were found for SR values at levels L3-L4, L4-L5 and L5-S1 respectively. The SR at L2-L3 had a mean value of 1.37 with a 95% confidence interval of (0.970, 1.78). At all levels, SRs were significantly lower for the spinal stenotic L3-S1 levels than for the L2-L3 control as confirmed by a student's t-test (p < 0.05). CONCLUSION: In a select population of patients with spinal stenosis confirmed by neuroradiological assessment, values of SRs were consistently and significantly lower than controls. We believe that measurements of SRs may provide reproducible quantitative measures for the diagnosis of spinal stenosis. SR values below the 95% confidence limit may be indicative of lumbar stenosis. Through the use of ratios, inherent differences in patient size are controlled for, thus allowing comparison of values between patients and treatment groups and effective clinical diagnosis of spinal stenosis.

Etiologies of shoulder pain in cervical spinal cord injury.

A protocol including physical examination, plain radiography, and shoulder arthrography was designed to study prospectively the causes of shoulder pain in patients with cervical spinal cord injury. Twenty-four patients (30 shoulders) were studied and subdivided into acute and chronic groups. The causes of shoulder pain in the acute group of 11 patients (15 shoulders) included capsular contracture or capsulitis or both in 6 shoulders; rotator cuff tears in 4; anterior instability in 2; and rotator cuff impingement, osteoarthritis with osteonecrosis, and osteoarthritis in 1 each. Of 13 patients (15 shoulders) assigned to the chronic group, the diagnoses included anterior instability in 5 shoulders; multidirectional instability in 3; capsular contracture or capsulitis or both in 3; and Charcot arthropathy, rotator cuff tear, rotator cuff impingement, and scapular pain in 1 each. To prevent and treat shoulder pain, therapeutic protocols for these patients must be individualized after a correct diagnosis is made.

Perspectives on the role of afferent signals in control of motor neuroprostheses.

K.O. Johnson reviews the architecture and low level neural mechanisms by which the external environment is transduced and encoded into the neural system, summarizing work that correlates neurophysiological and psychophysical testing with isolation of sensory components. The slowly adapting Type I afferent system is responsible for form and texture perception; the rapidly adapting afferent system is responsible for motion perception; and the Pacinian corpuscle system is responsible for vibratory sensation. R.R. Riso reviews the current level of understanding of the major factors to be considered in the design of a functional neuromuscular stimulation (FNS) grasp controller that uses cutaneous sensory feedback to detect slip. The elegant natural control scheme that matches the ratio of grip and lift forces to frictional conditions provides a model for implementing a slip-based control algorithm. D. Popovic discusses the possible use of recordings from more proximal peripheral nerves to determine needed information for synthesis of locomotion. The discussion is illustrated with an animal model where rule-based closed-loop control is used for the ankle joint during treadmill locomotion. Neural signals from the tibial and superficial peroneal nerves were employed to substitute for missing afferent input from cutaneous and proprioceptive sensors. The feasibility of more invasive intraneural electrodes for distinguishing sensory from motor information in mixed nerves is considered. M. Koris raises surgical and functional issues relevant to developing clinical FNS systems. C. Van Doren suggests alternative neurophysiological and engineering approaches.

Symptoms, functional status, and neuromuscular impairment following carpal tunnel release.

This study examined the resolution of symptoms, functional limitations and neuromuscular impairments following carpal tunnel release. Thirty-five patients were evaluated preoperatively and 6 weeks, 3 months, 6 months, and a mean of 27 months postoperatively. Evaluation consisted of physical examination (performed in a subset of patients) and previously validated questionnaire scales measuring symptoms, functional limitations, and satisfaction. Nocturnal pain, tingling, and numbness improved within 6 weeks after surgery. Weakness and functional status improved more gradually. Grip and pinch strength worsened initially, returned to pre-operative levels after about 3 months, and improved significantly by 24 months. The Tinel and Phalen signs remained positive in two and seven patients, respectively, after 2 years, and two-point discrimination remained abnormal in over half of patients after 2 years. These temporal patterns should be discussed with patients to foster realistic expectations of the response to surgery.

Dislocation of the elbow complicated by arterial injury. Reconstructive strategy and functional outcome.

Four cases of arterial injury complicating posterior dislocation of the elbow are described. All of these patients were treated by emergent revascularization; reconstruction of the soft-tissue constraints of the elbow joint was performed by using osseous suture anchors. Despite prompt treatment of the vascular injury and successful restoration of elbow articulation and stability, all of the patients had residual functional disability. The previous literature has not discussed the functional results of these reconstructions. This report underscores the severity of these injuries, details our reconstructive strategy, and analyzes the functional outcome of these badly traumatized extremities.

Compression of the ulnar nerve at the elbow in association with synovial cysts.

Compression neuropathies around joints in association with synovial cyst formation are rare events. A case of a posttraumatic ulnar nerve palsy in a patient with osteoarthritis of the elbow is presented. At operative exploration of the cubital tunnel, the ulnar nerve was found to be compressed by a synovial cyst. Cyst formation should be considered in determining the etiology of compression neuropathies in patients with posttraumatic and degenerative processes occurring around the joints.

A self-administered questionnaire for the assessment of severity of symptoms and functional status in carpal tunnel syndrome.

We developed a self-administered questionnaire for the assessment of severity of symptoms and functional status in patients who have carpal tunnel syndrome. The reproducibility, internal consistency, validity, and responsiveness to clinical change of scales for the measurement of severity of symptoms and functional status were evaluated in a clinical study. The scales were highly reproducible (Pearson correlation coefficient, r = 0.91 and 0.93 for severity of symptoms and functional status, respectively) and internally consistent (Cronbach alpha, 0.89 and 0.91 for severity of symptoms and functional status, respectively). Both scales had positive, but modest or weak, correlations with two-point discrimination and Semmes-Weinstein monofilament testing (Spearman coefficient, r = 0.12 to 0.42). In thirty-eight patients who were operated on in 1990 and were evaluated a median of fourteen months postoperatively, the mean symptom-severity score improved from 3.4 points preoperatively to 1.9 points at the latest follow-up examination, while the mean functional-status score improved from 3 to 2 points (5 points is the worst score and 1 point is the best score for each scale). Similar improvement was noted in twenty-six patients who were evaluated before and three months after the operation. We concluded that the scales for the measurement of severity of symptoms and functional status are reproducible, internally consistent, and responsive to clinical change, and that they measure dimensions of outcomes not captured by traditional measurements of impairment of the median nerve. These scales should enhance standardization of measurement of outcomes in studies of treatment for carpal tunnel syndrome.

Carpal tunnel syndrome. Evaluation of a quantitative provocational diagnostic test.

A diagnostic test combining the sensitivity of the Semmes-Weinstein monofilament measurement and the specificity of the wrist flexion provocational test has been evaluated in a group of 21 patients (33 hands) with electrodiagnostically verified carpal tunnel syndrome and 30 asymptomatic hands (controls). Semmes-Weinstein monofilament testing consisted of several sensory threshold measurements obtained by the application of force-calibrated Semmes-Weinstein monofilaments to each digit in the hand with the wrist in neutral position. The quantitative provocational diagnostic test employed Semmes-Weinstein measurements obtained with the wrist both in the neutral and flexed positions. The sensitivity (82%) and specificity (86%) of the combined test were calculated. It was more sensitive and specific than the wrist flexion test alone and more specific than the Semmes-Weinstein sensibility test. The combined test is recommended as the most accurate and sensitive quantitative clinical test for median nerve compression evaluated by the authors to date.