Radial- versus Ulnar-Based Extensor Retinaculum Reconstruction for Extensor Carpi Ulnaris Instability: A Cadaveric...

Area of Science:

• Orthopedic Surgery
• Anatomy
• Biomechanics

Background:

• Extensor carpi ulnaris (ECU) instability is a condition that can be addressed through subsheath reconstruction.
• The extensor retinaculum (ER) is utilized in these reconstructive procedures.

Purpose of the Study:

• To evaluate two described techniques for extensor retinaculum reconstruction of the ECU subsheath: radial-based (RBR) and ulnar-based (UBR).
• To compare the dimensions and efficacy of RBR and UBR in stabilizing the ECU tendon.

Main Methods:

• A cadaveric study involving 12 fresh frozen arms.
• Exposure of the ECU subsheath and ER.
• Creation and measurement of transverse and oblique RBR and UBR techniques originating from the ulnar aspect of the fifth dorsal compartment.

Main Results:

• The mean width of the ER was 50.3 ± 1.8 mm, and the mean retinacular height was 30.6 ± 2.0 mm.
• Mean transverse UBR (26.1 mm) and oblique UBR (36.0 mm) were longer than their respective RBR counterparts (18.3 mm and 21.6 mm).
• All reconstructions adequately stabilized the ECU tendon against subluxation during wrist movements.

Conclusions:

• Both UBR and RBR techniques are sufficient for stabilizing the ECU tendon in a cadaveric model.
• UBR reconstructions are significantly longer than RBR reconstructions.
• Both methods result in radial pull on the ECU tendon during pronation.