# Effect of prior mastectomy on outcomes following total shoulder arthroplasty

## TL;DR

This study finds that patients who had a mastectomy face higher risks of certain complications after shoulder replacement surgery.

## Contribution

The study identifies specific increased risks following TSA in patients with a history of mastectomy using a large matched cohort.

## Key findings

- Patients with prior mastectomy had higher postoperative lymphedema rates (3.48% vs. 0.67%).
- Mastectomy patients showed increased venous thromboembolism and infection risks.
- No significant differences were observed in two-year outcomes between groups.

## Abstract

Mastectomy and its associated treatments may alter shoulder biomechanics and soft-tissue integrity, yet their impact on total shoulder arthroplasty (TSA) outcomes remains unclear. This study evaluated short- and long-term complications following TSA in patients with a history of mastectomy.

A retrospective cohort analysis was performed using the TriNetX Research Network, including patients who underwent primary TSA. Individuals with a history of mastectomy were identified using procedural and diagnostic coding, and those with contralateral mastectomy and TSA were excluded. Propensity score matching 1:1 was performed to balance demographics and comorbidities. Ninety-day and two-year outcomes were compared between matched cohorts.

After matching, 1,865 patients with prior mastectomy were compared with 1,865 controls. Patients with a history of mastectomy had a significantly higher incidence of postoperative lymphedema (3.48% vs. 0.67%; RR 5.15; P < .0001). They also demonstrated increased risk of venous thromboembolism (4.56% vs. 3.11%; RR 1.47; P = .018). Overall postoperative infection rates were higher in the mastectomy cohort (3.96% vs. 2.70%; RR 1.47; P = .0378), including higher rates of cellulitis (2.81% vs. 1.72%; RR 1.63; P = .031). No significant differences were observed for 2-year outcomes.

Patients with a history of mastectomy undergoing TSA are at increased risk of perioperative postoperative lymphedema, thromboembolic events, and cellulitis. These findings highlight the importance of heightened perioperative surveillance.

The online version contains supplementary material available at 10.1007/s00402-026-06215-5.