Background Avascular necrosis (AVN) of the humeral head is a severe complication after proximal humerus fracture dislocations, and leads to a poorer clinical outcome and subsequent revision surgeries. The aim of the current study was to analyze the influence of time to surgery on the AVN rate after locked plating of dislocation fractures of the proximal humerus. Patients and methods This retrospective study included 30 patients with a mean age of 63 ± 14 years with dislocation fractures of the proximal humerus type B3 or C3 according the AO/OTA classification. The rates of AVN of the humeral head were determined clinically and radiographically. In addition, the clinical outcome was determined using the Constant score (CS), the age- and sex-adjusted Constant score (CS%), Disabilities of the Arm, Shoulder, and Hand (DASH) score, the range of motion, and complication and revision rates. Patients were subdivided into groups of subjects operated on early (≤48 h after trauma) and those with late surgery (>48 h after trauma), and the relative risk (RR) for complications and revisions was determined for both groups. Results After a mean follow-up of 37 months (range: 12–66 month) the mean CS% was 60 ± 24 and the mean DASH score was 32 ± 24 points. Ten patients (33%) developed a symptomatic AVN, and ten patients underwent revision surgery. Early surgery was performed on 25 patients while five patients underwent late surgery. After late surgery, all five patients developed AVN, and patients had a fivefold increased RR for AVN (p = 0.002) and subsequent associated surgical revision (RR = 3.3, p = 0.031). Conclusion In fracture dislocations of the proximal humerus, early surgery within 48 h of trauma significantly decreases the risk of AVN and subsequent surgery.

Conservative treatment of simple elbow dislocations can lead to complications such as persisting pain and restricted joint mobility. The current aim was to identify patients with deteriorated outcome after conservative treatment and to investigate a possible association with initial joint (in)stability. Sixty-eight patients (mean age 37.1 ± 17.2 years) with simple elbow dislocations received conservative treatment. After closed reduction, joint stability was tested by varus and valgus stress under fluoroscopy. According to the findings under fluoroscopy, three different groups of instability could be identified: (1) slight instability (joint angulation <10°; n = 49), (2) moderate instability (angulation ≥10°; n = 19) and (3) gross instability. Patients with gross instability (re-dislocation under stability testing) were treated with primary surgical ligament repair and therefore excluded from this study. Additionally, MRIs and radiographs were analysed regarding warning signs of instability such as the drop sign and joint incongruence. Main outcome parameters were the Mayo Elbow Performance Score (MEPS), range of motion (ROM), complications and revision rates. After 40.7 ± 20.4 months, the overall MEPS was excellent (94.2 ± 11.3) with a trend of slightly worse clinical results in group 2 (95.8 ± 9.0 vs. 90.0 ± 15.2 points; p = 0.154). In group 1, significantly more patients achieved an excellent result regarding the MEPS scoring system (77.6 vs. 52.6 %; p = 0.043) and elbow extension was significantly worse in group 2 (5.3 ± 9.9° vs. 1.4 ± 3.0°; p = 0.015). Seven treatment complications occurred in group 2 (36.8 %) compared with two in group 1 (4.1 %, p < 0.0001). Six patients (8.8 %) needed secondary surgery with an 8.4-fold higher risk for revision surgery in group 2 (p = 0.007). The presence of a positive drop sign or joint incongruence led to higher odds ratio (OR) for complications (OR = 15.9) and revision surgery (OR = 10.3). This study demonstrates that patients with moderate joint instability after simple elbow dislocation have a significantly worse clinical outcome, more complications and a higher need for secondary revision surgery following conservative treatment compared to patients with slight elbow instability.