Pressure mapping of the radioulnar carpal joint: effects of ulnar lengthening and wrist position.

The purpose of this study was to investigate the effects of ulnar lengthening and wrist position on force transmission through the radioulnar carpal joint in a forced dorsiflexed wrist position. Eight cadaveric arms were subjected to a 30 kg compressive load directed down the forearm towards the wrist. A pressure sensor recorded forces across the wrist joint with the triangular fibrocartilage complex intact and excised. The biomechanics of the distal radioulnar joint were altered by changes in ulnar length and wrist position. Pressures at the ulnolunate articulation increased as the ulna was lengthened and were significantly lower when the triangular fibrocartilage complex was excised. An inverse relationship between triangular fibrocartilage complex thickness and ulnar variance was shown. Greater increases in ulnolunate pressure were observed in more positive ulnar variant wrists.

Wrist loading patterns during pommel horse exercises.

Gymnastics is a sport which involves substantial periods of upper extremity support as well as frequent impacts to the wrist. Not surprisingly, wrist pain is a common finding in gymnasts. Of all events, the pommel horse is the most painful. In order to study the forces of wrist impact, a standard pommel horse was instrumented with a specially designed load cell to record the resultant force of the hand on the pommel during a series of basic skills performed by a group of seventeen elite male gymnasts. The highest mean peak forces were recorded during the front scissors and flair exercises (1.5 BW) with peaks of up to 2.0 BW for some gymnasts. The mean peak force for hip circles at the center or end of the horse was 1.1 BW. The mean overall loading rate (initial contact to first loading peak) ranged from 5.2 BWs-1 (hip circles) to 10.6 BW s-1 (flairs). However, many recordings displayed localized initial loading spikes which occurred during 'hard' landings on the pommel. When front scissors were performed in an aggressive manner, the initial loading spikes averaged 1.0 BW in magnitude (maximum 1.8 BW) with an average rise time of 8.2 ms; calculated localized loading rates averaged 129 BW s-1 (maximum 219 BW s-1). These loading parameters are comparable to those encountered at heel strike during running. These impact forces and loading rates are remarkably high for an upper extremity joint not normally exposed to weight-bearing loads, and may contribute to the pathogenesis of wrist injuries in gymnastics.

Wrist pain syndrome in the gymnast. Pathogenetic, diagnostic, and therapeutic considerations.

Gymnast wrist pain syndrome presents a difficult diagnostic and therapeutic challenge. It is common and debilitating among gymnasts, resulting in a reduction in training and performance, and may be the result of a response to repetitive trauma during the period of growth and development. This study was undertaken to define and characterize factors contributing to the causes and development of gymnast wrist pain and to establish an effective means of systematic and comprehensive evaluation and treatment. Thirty-eight collegiate gymnasts (20 UCLA: 9 female, 11 male; 18 NCAA: all male) were evaluated by radiograph and questionnaire. Seventy-five percent (22) of the males and 33% (3) of the females had had wrist pain for at least 4 months. The UCLA males averaged 2.82 +/- 1.94 mm positive ulnar variance; this was significantly greater than that of the NCAA males, who averaged 1.28 +/- 1.02 mm (P less than 0.02). The UCLA females averaged 1.44 +/- 1.88 mm positive ulnar variance. All of the gymnasts had significantly greater variance than had the controls, who averaged -0.52 mm (P less than 0.0001). The pommel horse routine was consistently responsible for wrist pain among the males. Anatomical and histological correlation of cryosections with magnetic resonance imaging (MRI) was performed to establish the usefulness of MRI in the diagnosis of wrist pain. MRI was able to differentiate the complex transitions between cortical and trabecular bone, articular surfaces, the ligaments, and the triangular fibrocartilage (TFC) complex of the wrist joint. A therapeutic algorithm was established to facilitate the evaluation and management of gymnast wrist pain. Arthroscopic surgery was successful, and arthroscopic findings correlated well with those of MRI and arthrography. Prospective studies are now underway in the pediatric and adolescent population to define further the causes and development of wrist pain problems in gymnasts.