INFLUENCE OF CAPSULE INJUR ON ELBOW RANGE OF MOTION

Articular capsule tear was common in elbow fractures, but the tissue mechanical environment during the wound repairing was not clear. The objective of this study was to evaluate the effects of different injury conditions on the stability of the elbow through animal experiments and finite element (FE) analysis. Different injury locations and repair conditions were considered in animal experiments: Type Ia (unrepaired anterior capsule), type Ib (repaired anterior capsule), type IIa (unrepaired whole capsule) and type IIb (repaired whole capsule). The elbow valgus angle at 0, 2 and 4 weeks was analyzed, and the tissue stress under different injury conditions (without injury, anterior capsule injury and complete capsule injury) was acquired through a FE model including active behavior of muscle. The maximum valgus angles of repaired elbow were smaller than those of unrepaired elbow. In completely capsule injury, the stress of ulna cartilage altered obviously compared with intact condition, and the peak stress occurred at the flexion angle of 60(circle). The stress was about 1.63 times that of intact state. The joint capsule was significantly more stressed than other ligaments and played an important role in the flexion of the elbow joint. This study could provide some advice for surgeons.