Correlation studies between acromion index and Multiloc intramedullary nail in the treatment of proximal humeral fracture

Background The proximal humeral fracture is a common clinical disease in the department of orthopedics,accounting for 4%-5% of all the fractures.More than 70% of the proximal humeral fractures occur in the elderly patients of over 60 years,and the number will increase year by year with the trend of population aging in China.The majority of proximal humeral fractures obtain good clinical prognosis through conservative treatment,but there are still some complications.The surgical treatment methods include close or open reduction and internal fixation and shoulder joint arthroplasty.The internal fixators are numerous,such as Multiloc intramedullary nail.During the intramedullary nailing treatment,Rispoli,etc.discovered the value of acromion index(AI)had an effect on the surgery,but no domestic literatures are reported at present.So this study assumes that the operation time,intraoperative blood loss,fracture healing time,postoperative functional scores and functional rehabilitation are different as the AI varies during the treatment of proximal humeral fractures with Multiloc intramedullary nail.In this study,seventeen patients of proximal humeral fractures were treated with Multiloc intramedullary nails from February 2014 to June 2015 in Sichuan provincial orthopedic hospital and the operation time,blood loss,fracture healing time,postoperative functional rehabilitation(anteflexion and uplift,internal and external rotation)and functional scores,etc.were recorded.All the clinical data were retrospectively analyzed to assess the correlation between AI and Multiloc intramedullary nailing in the treatment of proximal humeral fractures.Methods(1)General information.From February 2014 to June 2015,seventeen patients of proximal humeral fractures,including 6males and 11 females were treated with Multiloc intramedullary nails and followed up for 1year.The ages ranged from 48 to 67years with 61.4years on average.The AI ranged from 0.69to0.94 with 0.78 on average.The mean AI were 0.66 in male patients and 0.75 in females.According to Neer classification,there were 8cases(47%)of 2-part fracture,7cases(41%)of 3-part fracture and2cases(12%)of 4-part fracture,including olecranon fracture,distal radius fracture,rotator cuff tear and axillary nerve injury.8cases(47%)were injured in the dominant sides and 9cases(53%)were non-dominant sides.The causes were slips during walking in 9cases(53%),falls from bicycles in 5cases(29.4%)and traffic accidents in 3cases(17.6%)and all the injuries were closed fractures.This research was approved by the hospital ethics committee and all the subjects signed the informed consents.(2)Follow-ups and evaluation index.All the operations were performed by physicians of the same group,and the follow-ups and assessments were conducted by another 2senior orthopedic clinicians in the outpatient department.The postoperative routine visits were in the 1st,2nd,4th,6th,8th and 12 th months and the X-ray radiographs were taken at the same time.The shoulder activity scale,rating scale of the American shoulder and elbow surgeons(AESE)and Constant scoring system were applied in the evaluation of shoulder function.ASES is made by the association of American shoulder and elbow surgeons,including pain(50%)and life function(50%).The total score is 100 points and the higher score indicates the better function.The Constant scoring system is composed of pain(15points),muscle strength(25points),functional activity(20points)and range of motion of shoulder joint(40points),and the total score is 100 points.The higher score reveals the better shoulder function as well.(3)AI measurement Standard.The X-ray radiographs of anteroposterior view,lateral view and axillary view were taken in all the patients by 1senior and experienced radiologist with blind method.The respective distances from the lateral margin of acromion and the outer end of humeral head to the glenoid plane were measured by two physicians and the results were the mean values.All the radiographic images were provided by picture archiving and communication systems(PACS)in the hospital to avoid the measurement bias caused by different equipments and technical personnel.(4)Statistical analysis.The SPSS 22.0statistical software was adopted and the independent samples t test was used in the analysis of patient genders.The linear correlation analysis was applied in shoulder joint function,blood loss,operation time,fracture healing time,ASES scores and Constant scores.Theαvalue of inspection level was 0.05 on double sides and the difference was considered statistically significant with P 0.68),including 7cases of 2-part fracture,4cases of 3-part fracture and 1case of 4-part fracture.The mean age was 61.4years(48-69years)and the mean AI was 0.78(0.69-0.94);The mean intraoperative blood loss was 257.5 ml(150-300 ml);The mean degree of anteflexion and uplift was 161.6°(120°-180°)with 40°of abduction on average(20°-50°)and 106.5°of external rotation on average(85°-160°);The mean ASES score was 89.7points(80-96points)and the mean Constant score was 87.3points(79-98points);the mean fracture healing time was 2.25months(1.5-3months).(2)Postoperative complications.In the last follow-ups,no iatrogenic neurovascular injury,wound infection,internal fixation failure or humeral head necrosis were found in 17patients.One patient had ipsilateral elbow joint stiffness(110°of flexion and 50°of extension)but no muscle strength loss,muscle atrophy or other nerve damages,which was considered to be relevant with the 3months absence of outpatient follow-ups.The release surgery of elbow joint was performed 1year after Multiloc intramedullary nail fixation and the functional rehabilitation was acquired after operation(130°of flexion and 10°of extension).There was no obvious correlation between AI and postoperative bleeding complications.Conclusions No obvious correlation was found between the AI and the genders,ages and operation time in the treatment of proximal humeral fractures with intramedullary nails.The smaller AI indicated less intraoperative blood loss and fracture healing time.On the contrary,the larger AI indicated more intraoperative blood loss and fracture healing time.The patients with larger AI obtained higher ASES and Constant scores and better postoperative function(anteflexion,abduction and external rotation).Otherwise the patient with smaller AI acquired less ASES and Constant scores and relatively poor postoperative function.No operative complications occurred in the treatment of proximal fractures with Multiloc intramedullary nail and the AI had no significant correlation with the postoperative complications.