Abstract
Displaced 4-part fractures of the proximal humerus carry a significant risk of avascular necrosis (AVN). Recent reports showed incidence of AVN in some subtype of 4-part fractures was low. The purpose of this study was to show the new classification of the 4-part fractures of the proximal humerus and to report the incidence of AVN in each group. This study consisted of 51 cases (37 females, 14 males) with 4-part fractures of the proximal humerus. The mean age was 66.8 years old (range 29 to 88 years old) 4-part fractures without a dislocation were classified into 4 groups (valgus type, varus type, split head type, other type). 4-part fractures with a dislocation were classified into 4 groups (valgus impacted subcoracoid type, displaced subcoracoid type, axillary type, posterior dislocation type). In the valgus group (18 cases; open reduction and internal fixation (ORIF): 12 cases, prosthetic replacement: 4 cases, conservative treatment: 2 cases), no cases showed AVN. In the varus group (8 cases), all cases were treated by ORIF, 1 case showed AVN. In the split head group (4cases; ORIF: 3 cases, prosthetic replacement: 1 case), all 3 cases healed without AVN. In another group (4 cases; ORIF: 3 cases, prosthetic replacement: 1 case), 2 cases showed AVN. The valgus impacted subcoracoid group consisted of 6 cases (ORIF: 1 case (AVN(-)), prosthetic replacement: 5 cases), the displaced subcoracoid group consisted of 5 cases (ORIF: 3 cases (1 case, AVN(+)), prosthetic replacement: 2 cases), the axillary group consisted of 5 cases (ORIF: 1 case (AVN(+)), prosthetic replacement: 3 cases, resection: 1 case), and posterior dislocation had 1 case (prosthetic replacement). 4-part fractures without a dislocation were almost treated satisfactorily by ORIF without AVN. ORIF for 4-part fractures with a dislocation was challenging, but some cases may have healed without AVN by minimal invasive reduction and internal fixation.
