研究双侧长度对比法（对比法）测量锁骨中段骨折短缩程度的准确性及应用价值。

建立在术后锁骨骨折解剖复位的前提上，以校准法作为标准，分析伤时对比法的准确性，将对比法对同批患者采用不同摄片方式:前后位（posterioranterior，PA）正位、后前位（anteriorposterior，AP）15°头倾位、PA15°尾倾位测得并计算出的锁骨短缩值（双侧）与校准法计算出的锁骨短缩值（校准）进行Bland-Altman一致性分析。

3种摄片方式，对比法比校准法误差的95%一致性界限范围为：PA正位-10.98 ~ 10.00 mm，AP15°头倾位-18.98 ~ 10.95 mm，PA15°尾倾位-18.93 ~ 13.88 mm，3种摄片方式中PA正位误差相对较小，d_绝对值由小到大排列为：PA正位（4.22 mm）<PA15°尾倾位（6.53 mm）<AP15°头倾位（7.12 mm）（P = 0.044）。应用对比法测得锁骨缩短值>15 mm的共5例，这5例用校准法相同摄片方式测得>15 mm仅1例，符合率20%；应用校准法测得锁骨缩短值>15 mm的共10例，这10例用对比法相同摄片方式测得锁骨缩短值>15 mm仅1例，符合率10%。

应用对比法测量锁骨短缩程度（摄片方式PA正位、AP15°头倾位、PA15°尾倾位）误差很大，准确性不够，不适用于锁骨中段骨折手术指征的判断。在常用的锁骨摄片方式中，PA正位对比法测量出的锁骨短缩值更接近于真实值。

After acute mid-shaft clavicular fracture, the shortening degree is one of the relative indication for surgery. When shortening distance is over 15 to 20 mm, the surgery is necessary. It is important to accurately measure the shortening degree of clavicular fracture in the absence of open fractures with absolute indications such as vascular and nerve injury. It is difficult to measure the shortening degree of clavicle accurately on the X-ray film because of its S-shape, and different angles on the X-ray films make the test results variable. Which is the optimal measurement method is still controversial, and thus it brings difficulty to make appropriate treatment plan.

To investigate and compare the accuracy and application value of bilateral length comparison method in the assessment of shortening degree after mid-shaft clavicular fracture.

Based on the premise of anatomic reduction of postoperative clavicle fracture, the accuracy of bilateral clavicle length comparison method (bilateral method) was analyzed with the calibration method as the standard. The bilateral method was used to take different films for the same group of patients, including posteroanterior (PA) view, anteroposterior (AP) 15° cephalad view, and posteroanterior (PA) 15° caudal view. Bland-altman consistency analysis was performed for the measured and calculated collarbone shrinkage (bilateral) and the calculated collarbone shrinkage (calibration) .

With the 3 methods, the 95% consistency range of error of bilateral length comparison method compared with calibration method is -10.98 ~ 10.00 mm of PA view, -18.98 ~ 10.95 mm of AP 15° cephalad view and -18.93 ~ 13.88 mm of PA 15° caudal view respectively. Among these methods, the PA view had the smallest error relatively. The d_{absolute value} ranged from small to large were 4.22 mm on PA view, 6.53 mm on <PA 15° caudal view and 7.12 mm on AP 15° cephalad view (P=0.044) . A total of 5 cases of clavicle shortening value over 15 mm were measured with bilateral method. Among these 5 cases, only 1 case of over 15 mm was measured on the same radiographs with calibration method, with a coincidence rate of 20%. A total of 10 cases in which the clavicle shortening value over 15 mm was measured with the calibration method. Among these 10 cases, only 1 case had the clavicle shortening value of over 15 mm measured with the bilateral method on the same radiographs, with a coincidence rate of 10%.

Bilateral clavicle length comparison method was applied to measure the degree of clavicular shortening (PA view, AP 15° cephalad view and PA 15° caudal view) had large error and insufficient accuracy, which was not applicable to the judgment of surgical indications for mid-shaft clavicular fractures.