Acromion morphology affects acromion osteolysis and fracture after clavicular hook plate fixation / 中华创伤骨科杂志

ABSTRACT

Objective To investigate the impacts of acromion morphology on acromion osteolysis and fracture after clavicular hook plate fixation.Methods The clinical data were analyzed retrospectively of 255 patients who had been treated by clavicle hook plate from January 1st,2011 through December 31th,2012 at Department of Orthopedics,Shanghai Sixth People's Hospital.They were 182 males and 73 females with an average age of 46.6 years (from 14 to 76 years).Of them,130 were diagnosed with distal clavicular fracture,of which 126 were acute cases (within 14 days) and 4 chronic ones.The other 125 patients were diagnosed with acromioclavicular dislocation,of which 121 were acute cases and 4 chronic ones.Radiological data were reviewed to analyze the morphology and clinical outcome of acromion osteolysis.The hook-acromion (HA) angle was measured and the relationships between HA angles and different types of acromion osteolysis were statistically analyzed.Results The follow-up for the 255 patients averaged 6 months (from 1 to 24months).Acromion osteolysis with different migrations of clavicular hook plate was observed in 175 cases (68.6％),of which 77 were type Ⅰ (osteolysis with clavicular hook migration) and 98 type Ⅱ (osteolysis without clavicular hook migration).Acromion fractures were observed in the other 6 cases (2.35％).The HA angles in type Ⅰ osteolysis (11.05° ± 11.69°) were significantly larger than that in type Ⅱ (6.36° ± 11.47°)(P ＜ 0.05) Conclusions An increased HA angle may be a risk factor for acromion osteolysis with clavicular hook migration and acromion fracture.Variation in acromion morphology may increase the HA angle.Stress localization may be one of the mechanisms of acromion osteolysis and fractures.