RESUMEN
<p><b>OBJECTIVE</b>To investigate the causes and prevention of the complications about treatment of acromioclavicular joint dislocation (Tossy III) and unstable distal clavicular fracture (Neer II) with clavicular hook plate.</p><p><b>METHODS</b>From January 2001 to December 2011, 246 patients with acromioclavicular joint dislocation (Tossy III) and 222 patients with unstable distal clavicular fracture (Neer II) were treated with acromioclvicular hook plate fixation,including 348 males and 120 females with an average age of 45.4 years old ranging from 21 to 80 years old. The mean time from injury to operation was 30.8 hours (ranged from 1 h to 15 d). All patients had normal shoulder function before injury. According to Karlsson evaluation standard, the cases with excellent and good function of the shoulder joint were regarded as the normal group, and the cases with poor function of shoulder joint as the abnormal group. The comparison of the range of forward flexion,backward stretch, adduction, abduction and elevation of shoulder joints between two groups was performed. The data of impingement, subacromial osteolysis, acromioclavicular arthritis, clavicular stress fracture, downward acromioclavicular joint subluxation, hook cut-out and hook break were summarized.</p><p><b>RESULTS</b>All patients were followed up from 8 to 48 months with an average of 12.5 months. The results were excellent in 308 cases,good in 76,and poor in 84 according to Karlsson evaluation. The excellent and good rate was 82.1%. The difference of the range of forward flexion, backward stretch, adduction, abduction and elevation of shoulder joints between two groups had a statistically significant difference (P < 0.01). Among 84 poor cases, there were 41 (8.76%) in acromial impingement or inadequate place of plate hook, 12 (2.56%) with subacromial osteolysis or/and bursitis, 10 (2.14%) with acromioclavicular arthritis or painful shoulder caused by delayed dirigation,7 (1.50%) with clavicular stress fracture or interal plate upward, 6 (1.28%) with downward acromioclavicular joint subluxation, 5 (1.07%) with hook cut -out and 3 (0.64%) in hook break.</p><p><b>CONCLUSION</b>The clavicular hook plate is useful for the treatment of acromioclavicular joint dislocation (Tossy III) and unstable distal clavicular fracture (Neer II). The correct place and suitable preflex of plate hook,the restoration of fiber structure around the acromioclavicular joint and the advisable dirigation contribute to the modified rate of complications.</p>