Cortical contact is not necessary to prevent stem subsidence in cementless trapeziometacarpal arthroplasty: A follow-up study

Abstract

Cortical contact is not necessary to prevent stem subsidence in cementless trapeziometacarpal arthro-plasty: A follow-up study Le contact cortical n'est pas ne´cessaire pour pre´venir la migration de la tige dans l'arthroplastie trape´zo-me´tacarpienne sans ciment: e´tude de suivi Dear Editor, We previously reported that impacted cancellous bone can provide adequate stability for uncemented stems in the thumb metacarpal [1]. We based our conclusion on the fact that we did not observe radiographic subsidence at one year postoperatively in a series of 87 Maı¨aMaı¨a prostheses. In 77% of the cases, the stem was implanted without cortical bone contact on posteroanterior (PA) and lateral radiographic views. We reassessed the same patient group at a mean 6.1 years' follow-up (range, 2-10 years). Fifty-seven of the patients (75%) could be included, for 66 implants (76%). Three patients had died and two implants were removed because of trapezium fracture and infection. Like in the previous study, stem position was expressed as the ratio between the length of the metacarpal and the distance between the proximal end of the stem and the distal articular surface of the thumb metacarpal. Subsidence was determined by comparing stem position immediately after surgery and at last follow-up. Linear mixed models were used to obtain the mean and 95% confidence intervals for (1) stem position immediately after surgery, (2) stem position at final follow-up, and (3) change in stem position over time. On PA radiographs, the mean ratio immediately postoperatively was 1.414 (95% CI: 1.390; 1.438) and at follow-up 1.420 (95% CI: 1.390; 1.450). On average, this value decreased by 0.007 (95% CI: À0.009; 0.024) at follow-up, which was not statistically significant (p = 0.3871). On lateral radiographs, the ratio immediately postoperatively was 1.397 (95% CI: 1.374; 1.420) and at follow-up 1.406 (95% CI: 1.383; 1.428). The mean difference was 0.008 (95% CI: À0.0003; 0.016), and not significant (p = 0.060). The present study confirms that impacted cancellous bone can provide adequate primary stability to allow secondary bone ongrowth. However, other radiographic findings were observed. Minor heterotopic ossifications were present in most cases. One Hand Surgery and Rehabilitation 41 (2022) 707-708