A critical analysis of mechanical factors correlated with bone remodeling following total elbow arthroplasty.

Overview

Thirty elbows were critically reviewed for quantitative evidence of bone remodeling, with demonstrable bone remodeling noted in more than one half of the ulnae and humerii. Bone remodeling was analyzed statistically with independent variables of age, sex, handedness, diagnosis, implant design considerations, and implant alignment. Only implant design and alignment had a statistically significant impact on bone remodeling. Periarticular (zone 1) bone loss was statistically significantly correlated with a high percentage of diaphyseal medullary canal occupied by prosthesis, the presence of assymetric stem cortical contact, and lack of metaphyseal (zone 1) load transfer. Diaphyseal bone hypertrophy (zone 4) was statistically significantly correlated with a high percentage of diaphyseal medullary canal occupied by prosthesis (zone 4) and assymetric stem tip-to-cortical wall contact. Periarticular bone hypertrophy and diaphyseal bone atrophy did not occur. Fractures through the humeral condyles occurred in three elbows undergoing bone atrophy, but no implant loosening or failure could be correlated with bone remodeling. Bone remodeling does occur in a high percentage of stemmed elbow implants but to date has not been a factor in clinical failure.