Subsidence after Trapeziometacarpal Arthroplasty

Surgeons sometimes ascribe inadequate comfort and capability after trapeziometacarpal (TMC) arthroplasty to movement of the trapezium toward the scaphoid (subsidence or reduced trapezial space height [TSH]). We asked the following: (1) What percentage of studies found a relationship between subsidence of the metacarpal toward the distal scaphoid and measures of grip strength, capability, pinch strength, pain intensity, or patient satisfaction after TMC arthroplasty and what study characteristics are associated with having notable correlation? (2) What study factors are associated with greater postoperative TSH? (3) What is the mean subsidence over time?

We conducted a systematic review by querying PubMed, Cochrane, and Web of Science databases from 1986 and onward. Using inclusion criteria of TMC arthroplasty inclusive of trapeziectomy, ligament reconstruction and tendon interposition, tendon interposition, and prosthetic arthroplasty and a measure of subsidence, 91 studies were identified.

Seven of 31 study groups reported a correlation of subsidence with pinch strength, 5 of 21 with magnitude of incapability, 1 of 16 with grip strength, 2 of 20 with pain intensity, and none of 10 with satisfaction. Study factors associated with a relationship between subsidence and one of these measures included continents other than Europe. Among the 9 studies that measured TSH over time, the mean change in TSH was 5.0 mm ± 2.2 mm SD for visits less than 1 year after surgery and 5.5 mm ± SD 1.0 mm for visits 1 to 3.5 years after surgery.

The observation that most studies find no relationship between radiographic subsidence of an average of 5 millimeters and levels of strength, capability, comfort, or satisfaction after TMC arthroplasty suggests that primary surgeries may not benefit from a focus on limiting subsidence and revision arthroplasty ought not be offered based on this radiographic measure.