Larry K. Chidgey

Stress carpal tunnel pressures in patients with carpal tunnel syndrome and normal patients

Twenty-two patients with carpal tunnel syndrome scheduled to have a carpal tunnel release, and six volunteer control subjects had carpal tunnel pressures measured with their wrist in neutral position, maximum flexion, and maximum extension. The wrist was then repetitively flexed and extended to maximum position at a rate of 30 full cycles per minute for 1 minute. Pressures were then continually monitored and recorded at 30-second intervals. The pressures were found to be significantly elevated in the immediate post-exercise period in the patients with carpal tunnel syndrome, and they demonstrated a prolonged recovery time to reach the resting pressure when compared with the normal control subjects. This property of prolonged recovery time in patients with carpal tunnel syndrome suggests a possible cause for carpal tunnel syndrome in the occupational setting.

Histologic anatomy of the triangular fibrocartilage

The collagen arrangement of the triangular fibrocartilage complex was studied in 20 fresh cadaver wrists by means of standard and polarized light microscopy and scanning electron microscopy. The collagen fibres in the articular disk are arranged in undulating sheets oriented at oblique angles to each other. The fibers of the radioulnar ligaments are oriented longitudinally from the radial origin to the ulnar insertion. The origin of the articular disk from the radius is characterized by thick fibers 1 to 2 mm in length radiating from the radius into the articular disk. Five specimens were also injected with india ink. The radioulnar ligaments and the peripheral 15% to 20% of the articular disk are well vascularized, whereas the central 80% of the articular disk is avascular.

Interscalene perineural ropivacaine infusion:a comparison of two dosing regimens for postoperative analgesia.

Background and Objectives: A continuous interscalene nerve block with a perineural infusion of ropivacaine 0.2% at 8 mL/h has been shown to provide potent analgesia following moderately painful shoulder surgery. However, this high basal rate limits infusion duration for ambulatory patients who must carry the local anesthetic reservoir. We undertook this investigation to determine if the basal rate of an interscalene perineural ropivacaine infusion could be decreased by 50% with a concurrent 200% increase in patient-controlled bolus dose without compromising infusion benefits in ambulatory patients undergoing moderately painful orthopedic shoulder surgery. Methods: Preoperatively, patients (n = 24) received an interscalene perineural catheter and nerve block. Intraoperatively, patients received a standardized general anesthetic. Postoperatively, patients were discharged home with a portable infusion pump delivering ropivacaine 0.2% (500 mL reservoir) with a basal rate of 8 mL/h and a 2 mL patient-controlled bolus available each hour (“8/2” group, n = 12) or a 4 mL/h basal rate and 6 mL bolus dose (“4/6” group, n = 12), delivered in a randomized, double-blinded manner. Results: Patients in the 4/6 group had higher baseline pain scores only on postoperative day (POD) 2 (P = .011). However, these patients also experienced an increase in breakthrough pain incidence (5.8 boluses/d v 3.2, P = .035) and intensity (“worst” pain = 8/10 v 4/10, P < .05), sleep disturbances (2.0 v 0.0, P < .001), and a decrease in analgesia satisfaction (8 v 10, P = .003). Patients in the 8/2 group exhausted their local anesthetic reservoirs after a median of 61 hours, while the 4/6 group had a median of 131 mL remaining at infusion discontinuation after a median of 75 hours (P < .001). Conclusions: Following moderately painful ambulatory shoulder surgery, decreasing an interscalene perineural ropivacaine 0.2% basal rate from 8 to 4 mL/h provides similar baseline analgesia and lengthens infusion duration, but compromises other infusion benefits.

Evaluating dorsal wrist pain : MRI diagnosis of occult dorsal wrist ganglion

Fourteen patients with chronic dorsal wrist pain of unknown etiology underwent high-resolution magnetic resonance imaging (MRI) examination formatted to evaluate the scapholunate interval. Ten had MRI evidence that was diagnostic for an occult dorsal wrist ganglion. The average measured 4.7 mm at greatest diameter. Eight of 10 patients had the diagnosis confirmed, 7 at the time of surgery, and 1 at follow-up examination when the ganglion enlarged and was no longer occult. The other two opted for nonoperative management. The positive predictive value of a positive MRI finding for occult dorsal wrist ganglion was 100% in this small series. The use of a properly formatted high-resolution MRI in this patient population was diagnostic for occult dorsal wrist ganglion.

Treatment of comminuted distal radius fractures: an approach based on pathomechanics

Following dorsally displaced fractures of the distal radius, the classic position of immobilization is with the wrist flexed and in ulnar deviation. This is not the position of function and entails morbidity in the form of finger stiffness, which may require prolonged rehabilitation. We treated 20 consecutive, comminuted, intraarticular distal radial fractures using a new external fixation system with the wrist in a neutral to extended position, thereby promoting metacarpophalangeal joint flexion by relatively relaxing the finger extensor tendons. Supplemental pin fixation was used in eight cases. Most patients were performing active digital motion on the day of surgery and 95% maintained functional finger motion during treatment. All fractures healed uneventfully. Palmar tilt was restored in 55% of patients in spite of a wrist neutral or extended position. This method of fixing distal radial fractures allows restoration of anatomy while avoiding hand stiffness.

Acute carpal tunnel syndrome caused by pigmented villonodular synovitis of the wrist.

An 89-year-old woman developed an acute carpal tunnel syndrome secondary to hemarthrosis associated with pigmented villonodular synovitis of the wrist. Pigmented villonodular synovitis is rare in a patient of this age and is an unusual cause of carpal tunnel syndrome.

Quantification of the relationship between dynamic grip strength and forearm rotation: a preliminary study.

Clinically, the measurement of grip strength is a static measure. It is performed in a standardized posture with the arm at the side, elbow flexed to 90 degrees, and the wrist-forearm positioned in neutral. Many functional activities require dynamic grip strength when an individual moves the wrist-forearm while simultaneously gripping an object. This preliminary study investigated dynamic forearm rotation with isometric grip strength over real time. Thirty wrists from 15 normal subjects were measured with a tilt sensor attached to a strain gauge dynamometer. Each subject underwent randomized trials of maximally gripping the dynamometer while rotating the forearm over a 10-second period. A multiple-regression model was fit for the parameters of extremity, forearm rotation order, fatigue, and loss of strength with supination and pronation. For each parameter, the mean and standard error of its estimate were computed and compared with zero. The significant effects (p = 0.05) of interest were for fatigue and the loss of grip strength from 70 degrees of supination to the end range of supination. Comparisons to existing static grip strength literature were made. We concluded that there is a decrease in grip strength over time as a result of fatigue, there is a decrease in grip strength at supination angles greater than 70 degrees. There is no decrease in grip strength resulting from supination angles less than 70 degrees, nor is there a decrease in grip strength with pronation when measured dynamically. It is suggested that there may be a difference in static and dynamic GS measurements related to forearm rotation.

EXPERIMENTAL INVESTIGATION OF THE SCAPHOID STRAIN DURING WRIST MOTION

The scaphoid is the most frequently fractured of the carpal bones [Taleisnik, J., The Wrist, Churchill Livingstone, New York (1985)]. This project was undertaken to qualitatively evaluate the strain in the scaphoid during wrist motion using a newly developed strain gage method. Strain gage rosettes were mounted within the scaphoid and the range of motion of the hand was monitored using a custom designed electrogoniometer and data acquisition system. Ten specimens were utilized for this study. Results indicated that supination/pronation (S/P) of the forearm did not affect the strain in the scaphoid. A map of the strain in the waist of the scaphoid, as a function of flexion/extension (F/E) and radial/ulnar deviation (R/U), was generated. The contour plot of scaphoid strain vs range of motion (ROM) shows a valley where strains are low. Minimum scaphoid strain was found near neutral F/E and 15 degrees of ulnar deviation.

Neuropathic Sternoclavicular Joint Secondary to Syringomyelia: A Case Report

A 14-year-old boy is presented with syringomyelia and a neuropathic sternoclavicular joint. Recognition of neuropathic arthropathy of the upper extremity is important when a massive, destructive joint lesion exists in a patient with syringomyelia.

The Mysterious Wrist

All manuscripts submitted to the Journal of Hand Therapy must be accompanied by an abstract of not more than 150 words. Abstracts of studies should be informative, stating purpose of study, methods used, results and conclusions. Abstracts of articles other than studies should indicate the principal topic to be discussed.