Citations

A retrospective study of 45 patients with symptoms of wrist pain and weakness with clinical evidence of instability is presented. These patients had normal intrinsic interosseous ligaments demonstrated arthrographically or surgically. They were followed for a minimum of 18 months and an average of 5.8 years. All patients demonstrated instability of the proximal carpal row which is referred to as carpal instability non-dissociative (CIND). Seven patients were treated non-operatively and 38 were treated operatively. Surgical management consisted of soft tissue reconstruction directed at the area of instability in 34 cases, joint levelling osteotomy in six, three of whom also had soft tissue reconstructions, and mid-carpal fusion in one. The overall good and excellent results were a disappointing 56% and there was no significant difference between the non-surgical and surgical groups. The best results were found in the ulna-minus CIND patients who underwent a joint levelling osteotomy, with 83% good and excellent results. CIND is associatedwith extrinsic ligamentous laxity; however, significant difficulty exists in locating the precise areas of maximum pathology. This accounts for the unpredictable results of treatment. As our understanding of the pathomechanics of CIND improves, the treatment will become more specific and the results should improve.

Carpal tunnel syndrome is one of the many so-called cumulative trauma disorders thought by some to be related to the performance of repetitive tasks in the work-place. The cause of this disorder is unknown. We have observed lumbrical muscle incursion into the carpal tunnel during finger flexion. This study was conducted to determine the amount of this incursion in normal wrists. Five cadaver upper limbs were analyzed radiographically with radiopaque markers on the flexor retinaculum and the lumbrical muscle origins in four finger positions: full extension, 50% flexion, 75% flexion, and 100% finger flexion. The lumbrical muscle origins were an average of 7.8 mm distal to the carpal tunnel in full finger extension. They moved an average of 14 mm into the carpal tunnel with 50% finger flexion, 25.5 mm with 75% flexion, and 30 mm with 100% flexion. Abnormal lumbrical muscles have been cited as a possible cause of carpal tunnel syndrome. These findings suggest that lumbrical muscle incursion during finger flexion is a normal occurrence and is a possible cause of work-related carpal tunnel syndrome.

Endoscopic carpal tunnel release has been shown in recent studies to result in a significant number of incomplete releases of the distal aspect of the flexor retinaculum. The significance of this complication is unknown. To address this question, we measured the amount of carpal arch widening after incomplete and complete release. The mean amount of change in carpal arch width in five cadaveric hands after partial release (all but the distal 4 mm) was 0.74 mm, which was statistically significant. The mean additional change after release of the remaining 4 mm of the flexor retinaculum was 0.12 mm, which was not significant. Incomplete release of the distal 4 mm of the distal aspect of the flexor retinaculum allows carpal arch widening that is no different from that of complete sectioning of the flexor retinaculum in the cadaver limb.

12 adult cadaver wrists were dissected to identify the regions of origin of the four palmar radio-carpal ligaments. A non-dimensionalized value, called the radio-carpal ligament ratio (RLR), was defined as the width of ligament origin from the radius divided by the length of the capitate. Both values were measured directly from radiographs of the cadaver specimens. The RLRs for the four palmar radio-carpal ligaments were found to be statistically consistent. We applied the RLR concept retrospectively to 20 wrists with intraarticular distal radius fractures requiring open reduction. It was found that those fracture patterns in which the fracture fragment ratios (FFR: widths of the fracture fragments divided by the length of the capitate) were outside the limits of corresponding RLRs had clear intra-operative evidence of palmar radio-carpal ligament disruption, while those with FFRs within the limits of corresponding RLRs were noted to have no ligament disruption.

The boundaries of Guyon’s canal have recently been redefined by a series of anatomical dissections. These showed that the confines of this space do not extend from the pisiform to the hook of the hamate, as currently accepted. The fascial roof extends radial to the hook of the hamate, which allows the ulnar neurovascular bundle to course radial to the hamate hook. The position of the ulnar nerve and artery is of particular significance for endoscopic carpal tunnel release. Most endoscopic devices are designed to divide the flexor retinaculum just to the radial aspect of the hamate hook. Utilizing cross-sectional analysis of nine cadaver specimens, we found the ulnar artery to course radial to the hamate hook in five and palmar to it in four. Therefore, the ulnar artery may be at greater risk of injury during endoscopic procedures than previously recognized.

Pisotriquetral arthrosis in young patients is considered rare and the diagnosis may be difficult to distinguish from other ulno-carpal problems. 12 patients under 40 years of age (15 cases) who underwent pisiformectomy were reviewed at a mean of 41 months. Patients with a good history of trauma and a positive response to intra-articular local anaesthetic injection did well. Others with an indefinite history and bilateral symptoms did not do so well. Trispiral tomography is the radiological investigation of choice.

Muscle physiological cross-sectional area, as defined and measured by dividing the volume of the muscle by its fibre length, is proportional to the maximum strength of the muscle. It is one of the important parameters when considering muscle mechanics in sports science and, clinically in tendon transfer procedures. This study reports that tendon cross-sectional area correlated well with the physiological cross-sectional area of associated muscles.

The chondroepitrochlearis muscle is an extremely rare muscle, arising from the pectoralis major, crossing over the neurovascular bundle in the axilla and inserting into the brachial fascia and medial epicondyle of the humerus. This paper presents the first known neurological complication due to the chondroepitrochlearis muscle.

In order to determine the mechanical properties of the fibro-osseous pulleys in the hand, the diaphyseal annular pulleys, the volar plate annular pulleys and the cruciate or condensable portions were tested. A custom-made loading device provided proper fit of the soft tissues for a uniform distribution of the pulley load during testing. The A2 pulley was found to be the strongest of the pulleys; the A1 and A4 were the next strongest. The A3 pulley was nearly equal in mean breaking strength to the other annular pulleys, but in absolute breaking load was considerably weaker because of its shortness. The A4 was the least compliant of the pulleys. We concluded that the fibro-osseous A2 and A4 were mechanically stronger and stiffer pulleys than the A1, A3, A5 (volar plate) pulleys. In testing one type of pulley reconstruction, we found that the “belt loop” technique of Karev nearly matched the annular pulleys in strength and energy absorption.