Shoulder arthroplasty after prior external beam radiation therapy: a matched cohort analysis.

BACKGROUND

External beam radiation therapy (XRT) is a commonly used therapeutic modality for the treatment of various chest wall and axillary malignancies. Despite the known risk of local soft tissue dysfunction, and possibly compromised bone ingrowth for cementless implants, there remains limited data on the impact of prior XRT in a shoulder arthroplasty (SA) cohort. This study evaluated the outcomes of primary SA in patients with prior XRT compared to a matched cohort (MC).

METHODS

Over a 27-year time period (1993-2020), 80 primary SAs (7 hemiarthroplasties [HAs], 29 anatomic total shoulder arthroplasties [aTSAs], and 44 reverse shoulder arthroplasties [rTSAs]) with previous XRT to the upper chest or axillary region and a minimum of 2-year follow-up were included. This cohort was matched (1:2) according to age, sex, body mass index (BMI), implant, and year of surgery with patients who had undergone HA or TSA for osteoarthritis or RSA for cuff tear arthropathy. Clinical outcomes including pain, active shoulder range of motion (ROM), strength, complications, and reoperations inclusive of revision surgery were assessed.

RESULTS

The XRT cohort consisted of 71 (88.8%) women with a mean age of 70.9 (range, 43-87) years, BMI of 30.9 ± 7.6, and follow-up period of 6.6 years (range, 2.0-28.2). In these patients, SA led to substantial improvements in pain, ROM, and strength across the entire cohort. When compared to the MC, the XRT group demonstrated a lower final postoperative forward elevation (FE) (111° vs. 126°; P = .013) and less improvements in pain (5.3 vs. 6.2; P = .002), FE (34° vs. 54°; P = .002), and external rotation (13° vs. 24°; P < .001). There were 14 (17.5%) complications and 7 reoperations in the XRT group, with rotator cuff failure after HA or TSA (n = 4 of 36; 11.1%) as the most common complication and no instances of loose humeral components. The XRT group had a higher rate of complications (17.5% vs. 8.1%; P = .03) but not reoperations (8.8% vs. 3.1%; P = .059). When evaluated by implant, rTSA demonstrated the lowest rate of reoperations followed by aTSA and HA (2.3% vs. 10.3% vs. 42.9%; P = .002).

CONCLUSIONS

Primary SA is an effective treatment modality for the improvement of pain, motion, and strength in patients with a history of prior XRT. However, when compared to patients without prior XRT, less clinical improvement and a higher rate of postoperative complications were observed.