Abstract
Introduction
The reliability of currently available proximal humeral fracture classi?cation systems has been shown to be poor, giving rise to the question whether a more objective measure entails improved predictability of surgical outcome. This study aims to apply a novel software system to predict the functional range of motion of the glenohumeral joint after proximal humeral fracture.
Method
Using a validated system that simulates bone-determined range of motion of spheroidal joints such as the shoulder joint, we categorically analysed a consecutive series of 79 proximal humeral fractures. Morphological properties of the proximal humerus fractures were related to simulated bone-determined range of motion.
Results
The interobserver variability of range of motion assessment using our system showed excellent agreement (0.798). Maximal glenohumeral abduction and forward ?exion of intra-articular fractures were 34.3±6.6 SE and 60.7±12.4 SE degrees. For fractures with a displaced greater tuberosity abduction was 75.0±5.9 SE and forward flexion was 118.2±4.9 SE degrees, whilst for fractures where both tuberosities had been displaced they were 60.0±10.9 SE and 69.6±13.4 SE degrees respectively. For non-intra articular fractures without displaced tuberosities movements were 89.3±3.3 SE and 122.6±3.4 SE degrees respectively. The head inclination angle was positively correlated with maximum abduction (0.362, p = 0.014). Offset was negatively correlated with maximum abduction, but not statistically signi?cant (0.834, p = 0.087).
Conclusion
This study has demonstrated a novel and effective tool allowing the prediction of functional motion after proximal humeral fracture based on bone anatomy. The study demonstrates that intra-articular fractures generally have the worst prognosis with regards to bone-determined ROM. Fractures with displaced tuberosities show more motion limitations for abduction than for forward ?exion. A reduced head inclination angle is a strong predictor of limited bone-determined range of motion for all types of proximal humerus fractures.
