Resection-suspension arthroplasty according to Epping for thumb carpometacarpal osteoarthritis

Anatomical orientation by palpation and marking of anatomical landmarks:

• 1. SSF = Extensor tendon compartment
• 1. CMC joint (saddle joint) = Carpometacarpal joint
• STT joint = Scapho-trapezo-trapezoidal joint

Longitudinal skin incision dorsally over the saddle joint with an arched extension proximally over the 1st SSF. Sharp transection of the subcutis under bipolar coagulation of individual veins.

Sequential presentation of the trapezium bone with the adjacent joints (1st CMC, ST joint). The radial artery crossing over the trapezium bone is carefully dissected and secured with a rubber loop so that it can be safely preserved during the operation.

(CMC joint = Carpo-metacarpal joint, 1st CMC = Thumb saddle joint; ST joint = Scapho-trapezoidal joint)

Caution

• Cutaneous branches of the dorsal branch of the radial nerve or the medial antebrachial cutaneous nerve
• Radial artery

First, the joint capsule of the saddle joint is opened longitudinally, and the trapezium is detached from its surroundings. Expose the STT joint. The trapezium bone is osteotomized longitudinally with a Lambotte chisel and detached from the remaining joint capsule. Remove the bone fragments with a Luer forceps. Special attention should be paid to the removal of osteophytes, which typically lie between the base of the 1st and 2nd metacarpals.

Careful inspection of the joint surfaces (metacarpal base and scaphoid) as well as the STT joint. In cases of severe osteoarthritis, consider partial resection of the trapezoid.

Caution

• FCR tendon (flexor carpi radialis tendon)! The osteotomy of the trapezium bone with a chisel is performed in the direction of the FCR tendon, approximately 45° from proximal-radial to distal-ulnar. This way, the chisel does not transect the palmarly located FCR tendon transversely.

• Osteophytes at the base of the 1st and 2nd metacarpals and the hemihamulus of the trapezium can be very persistent.