Trapeziometacarpal total joint replacement as an alternative to trapeziectomy depends on trapezium height:...

Surgical indications for trapeziometacarpal (TMC) total joint replacement for thumb basal joint osteoarthritis (OA) are increasing. However, complications following this procedure are not insignificant. To avoid complications, preoperative planning with measurement of trapezium height is indicated to ensure a cup is not implanted in the trapezium if its height is less than 8 millimeters. The objective of our study was to analyze a series of preoperative radiographs of patients managed by trapeziectomy and suspensionplasty in our department, and to assess the possibility of a surgical alternative-total joint replacement-based on the trapezium's height. We also wanted to determine whether radiological height was influenced by the radiological progression of the thumb OA. A single-center retrospective study based on available medical records was conducted. The patients included had TMC OA refractory to conservative treatment and were managed surgically by trapeziectomy and suspensionplasty between 2012 and 2018. Sixty-seven patients were eligible. Based on the Eaton-Littler classification of radiological TMC OA, our case series had 0% (n=0) stage I, 36% (n=24) stage II, 42% (n=28) stage III and 22% (n=15) stage IV findings. We measured the radiological trapezium height on AP and lateral views as described by Kapandji. These were 10.6mm and 10.8mm for stage II, 9.6mm and 8.9mm for stage III, 8.6mm and 7.8mm for stage IV, respectively. Eighty-six percent of patients had a trapezium height suitable for total joint replacement. The radiological height decreased significantly with the OA stage. At stage IV, the average height fell below the 8-mm threshold, compromising the surgical indication for total arthroplasty.