Humeral bone resorption after anatomic shoulder arthroplasty using an uncemented stem

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Radiology

Background:

• Bone resorption around implants is common in hip arthroplasty but less studied in shoulder procedures.
• This study focuses on the prevalence and risk factors of humeral bone resorption following shoulder arthroplasty.

Purpose of the Study:

• To investigate the prevalence of humeral bone resorption after total shoulder arthroplasty (TSA) and humeral head replacement (HHR).
• To identify risk factors associated with bone resorption following shoulder arthroplasty.

Main Methods:

• Retrospective analysis of 147 shoulders undergoing TSA or HHR with uncemented stems (2008-2015).
• Assessment of bone resorption grades and identification of risk factors including implant type, stem coating, and patient demographics.

Main Results:

• Bone resorption was observed in 85.7% of patients, with grade 4 resorption in 18.4%.
• Common sites for resorption included zones 1, 2, and 7 (greater tuberosity, lateral diaphysis, calcar region).
• Humeral head replacement (HHR), on-growth stem coating, and high implant occupation ratio were risk factors for significant resorption.

Conclusions:

• Humeral bone resorption is a frequent complication after shoulder arthroplasty, particularly around the greater tuberosity and diaphysis.
• Female sex, HHR with rotator cuff repair, on-growth stem coating, and high implant occupation ratio are significant risk factors.
• Understanding these factors can help optimize implant design and surgical techniques to mitigate bone resorption.