Arch Hand Microsurg.  2024 Jun;29(2):75-81. 10.12790/ahm.23.0043.

Effects of distal ulnar morphology on symptomatic extensor carpi ulnaris (ECU) subluxation and the clinical outcomes of anatomic ECU subsheath reconstruction: a retrospective observational study

• Kang SJ
• Kim JN
• Kim YS
• Lee SJ

• KMID: 2556356
• DOI: http://doi.org/10.12790/ahm.23.0043

Abstract

Purpose
This study aimed to evaluate the association between distal ulnar morphology and symptomatic extensor carpi ulnaris (ECU) subluxation and assess the results of anatomic ECU subsheath reconstruction.
Methods
To investigate the effects of distal ulnar morphology on symptomatic ECU subluxation, we compared distal ulnar morphology using magnetic resonance imaging among three groups: group 1 (symptomatic ECU subluxation, 12 cases), group 2 (non-symptomatic ECU subluxation, 24 cases), and group 3 (no ECU subluxation, 24 cases). Distal ulnar morphology was evaluated using ulnar variance, ulnar styloid length, and ECU groove depth. Clinical outcomes were evaluated using the Patient-Related Wrist Evaluation (PRWE) score, the Disabilities of the Arm, Shoulder, Hand (DASH) score, grip strength, and the range of motion of the wrist joint.
Results
Ulnar variance showed a statistically significant difference between groups 1 and 2, and ECU groove depth showed statistically significant differences between groups 1 and 2 and between groups 2 and 3. Ulnar styloid length showed no statistically significant between-group differences. In patients with symptomatic ECU subluxation, there was a significant increase in the range of motion in supination and grip strength, and a significant decrease in the DASH score (from 40 to 9) and PRWE score (from 48 to 12).
Conclusion
Negative ulnar variance was associated with symptomatic ECU subluxation, and shallow ECU groove depth was correlated to asymptomatic ECU subluxation, but unrelated to symptoms. Anatomic ECU tendon sheath reconstruction was identified as an effective surgical method.

Figure

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  Fig. 1. Measurement method for ulnar variance using magnetic resonance imaging. R, distal radius perpendicular line; U, distal ulnar perpendicular line.

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  Fig. 2. Measurement method for ulnar styloid length using magnetic resonance imaging. S, styloid tip perpendicular line; F, fovea perpendicular line.

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  Fig. 3. "Measurement method for extensor carpi ulnaris groove depth using magnetic resonance imaging. G, groove outline; dotted line, groove depth.

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  Fig. 4. (A) Identify extensor retinaculum. (B) Open the extensor retinaculum and check the subsheath (this figure shows periosteal stripping of ulnar leaf on the extensor carpi ulnaris [ECU] subsheath). (C) Check the ECU groove of the distal ulna. (D) Reduce the ECU tendon into the ECU groove and check driving. (E) Check the ECU subsheath tension and suture position. (F) Positioning the 1.0-mm JuggerKnot anchor. (G) Reconstruction is performed on the subsheath anatomic position. (H) Extensor retinaculum repair was performed.

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  Fig. 5. The changes in Disabilities of the Arm, Shoulder, Hand (DASH) score and the Patient-Related Wrist Evaluation (PRWE) score.

Reference

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