Pathologies of the Extensor Carpi Ulnaris (ECU) Tendon and its Investments in the Athlete

ArticleinHand clinics 28(3):345-56, ix · August 2012with23 Reads
DOI: 10.1016/j.hcl.2012.05.049 · Source: PubMed
Those who have dedicated significant time to the study and care of stick-and-ball athletes have an appreciation for the unique anatomy, unusual forces, and proclivity for injury. It is imperative that hand surgeons involved in the care of baseball, hockey, tennis, and golf athletes appreciate the anatomic and mechanical elements of extensor carpi ulnaris (ECU) pathology. It is necessary to maintain a high level of suspicion for ECU problems, among other ulnar wrist pathologies, as well as acute diagnostic skill and a portfolio of therapeutic alternatives for their treatment.
  • [Show abstract] [Hide abstract] ABSTRACT: The purpose of this study was to evaluate the association between distal ulnar morphology and extensor carpi ulnaris (ECU) tendon pathology. We retrospectively reviewed 71 adult wrist MRI studies with ECU tendon pathology (tenosynovitis, tendinopathy, or tear), and/or ECU subluxation. Subjects did not have a history of trauma, surgery, infection, or inflammatory arthritis. MRI studies from 46 subjects without ECU tendon pathology or subluxation were used as controls. The following morphological parameters of the distal ulna were measured independently by two readers: ulnar variance relative to radius, ulnar styloid process length, ECU groove depth and length. Subjects and controls were compared using Student's t test. Inter-observer agreement (ICC) was calculated. There was a significant correlation between negative ulnar variance and ECU tendon pathology (reader 1 [R1], P = 0.01; reader 2 [R2], P < 0.0001; R1 and R2 averaged data, P < 0.0001) and ECU tendon subluxation (P = 0.001; P = 0.0001; P < 0.0001). In subjects with ECU tendon subluxation there was also a trend toward a shorter length (P = 0.3; P <0.0001; P = 0.001) and a shallower ECU groove (P = 0.01; P = 0.03; P = 0.01; R1 and R2 averaged data with Bonferroni correction, P = 0.08). ECU groove depth (P = 0.6; P = 0.8; P = 0.9) and groove length (P = 0.1; P = 0.4; P = 0.7) showed no significant correlation with ECU tendon pathology, and length of the ulnar styloid process showed no significant correlation with ECU tendon pathology (P = 0.2; P = 0.3; P = 0.2) or subluxation (P = 0.4; P = 0.5; P = 0.5). Inter-observer agreement (ICC) was >0.64 for all parameters. Distal ulnar morphology may be associated with ECU tendon abnormalities.
    Article · Mar 2014
  • [Show abstract] [Hide abstract] ABSTRACT: Purpose: Injury to the extensor carpi ulnaris (ECU) fascial supports on the distal ulna can result in ulnar-sided wrist pain, particularly when the tendon subluxates medially out of the fibroosseous groove with forearm rotation. To better understand the potential risk factors for injury and the indications for modifying the ECU groove, we have evaluated and quantified the morphology of the ECU groove and tendon. Methods: Axial plane magnetic resonance imaging of the wrist obtained for triangular fibrocartilage complex and intercarpal pathology in 60 patients were reviewed. Mean and standard error of the mean were calculated and unpaired Student t tests performed to compare groove width and depth, radius of curvature of the groove, carrying angle, and tendon-to-groove ratio. Results: There were 23 females (38%), and the mean patient age was 40 years (range, 17-71 y). The average ECU groove depth and standard error of the mean was 1.4 mm ± 0.1 mm. The radius of curvature for the ulnar ECU groove was found to be 7.0 mm ± 0.4 mm with a carrying angle of 143° ± 2°. In neutral forearm rotation, the average ratio of the width of the ECU tendon to groove was 0.7 ± 0.02. The data approximated a normal distribution. There were no statistically significant differences in these measurements between the triangular fibrocartilage complex and the intercarpal pathology subgroups. Conclusions: Variability in the relationship of the ECU groove and tendon may combine to represent risk factors for tendinosis or tendon subluxation. There may be a more normal distribution of ECU groove morphology than previously recognized. Clinical relevance: ECU injuries may require clinical imaging of the tendon and subsheath, in addition to potential surgical reconstruction and ulnar groove deepening. This report establishes the normative morphology and depth of the ECU groove and provides a comparative baseline when considering treatment modalities.
    Article · Oct 2014
  • [Show abstract] [Hide abstract] ABSTRACT: To improve its mechanical advantage, the extensor carpi ulnaris (ECU) muscle uses, as if it was a pulley, the 6th extensor compartment, a dorsal fibro-osseous tunnel formed by the ulnar sulcus and the ECU tendon sub-sheath. Rupture or insufficiency of that sheath may allow anteromedial ECU tendon subluxation and subsequent destabilization of the distal radioulnar and ulnocarpal joints. Sometimes, it is not sheath problem, but excessive friction between the sheath and the tendon what causes a painful degeneration of the tendon (tendinosis) with or without tendon entrapment. The term ECU tendinopathy has been chosen to designate all painful ECU anomalies resulting from a dysfunctional 6th extensor compartment. ECU tendinopathies are frequent among sportsmen using bats, sticks or clubs. There are 2 major types of tendinopathy: 1) constrained tendinopathies, where there is entrapment of a thickened overused tendon, and 2) unconstrained tendinopathies, where a ruptured ECU sub-sheath allows the ECU to sublux in a volar direction, a position precluding all its stabilizing potential. In the first type, the goal of the treatment is to avoid further degeneration and subsequent rupture of the diseased tendon; in the second, to re-establish the normal connections between the ulna and the ECU tendon. This article reviews the management of the most frequent ECU tendinopathies.
    Article · Sep 2015
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