The Occurrence Of The Osteo-line On Femur Neck And Its Application

Objective: With the extend of the cortex from the intertrochanter to the femur neck a osteo-line nautrally shaped on base of the femur neck.Use of this line as a mark to guide the osteotomy on fenmur neck in hip athroplasty highly improved the accurancy of the osteotomy and significantly reduced the risk of leg length discrepancy.This technique is esay to learn and convenience to be popularized and applied,To verify the occurrence of the osteo-line,test the apply of this technique and investivate the relativity of this methord and other methods that used to decreased leg length descripancy we carried out this study.Methods:1 Observation and measurement of femur specimensWe selected 64 femur sepcimens keeped by department of anatomy in Hebei Medical University,consist 9 left fumur and 55 right femur.We observed the shape of the femur neck,noticed that there is a osteo-line naturally shaped on the femur ncek.We divided it into 3 types.In type A the osteo-line is clear to be observed.In type B the osteo-line becomes ambiguous when extended from the top to the bottom.In type C there is no osteo-line observed on the femur neck.We recored occurrance ratio of the osteo-line on femur neck,and identify their types.Then measure the distance between the line and the less trochanter tip.We define the distance of the front line as "a",and the back line as "b".After recorded these data,we take picture for each specimen to test the accuracy of our measurement.In order to dismiss the influence of the iliopsoas insertion on the less trochanter,we measeured its length and recoreded it as "c".Then a-c/2 and b-c/2 were uesd respcetively for the distance from line to the less trochanter that we can see in operation.2 Clinical use of the osteo-lineTotal 45 patients who received unilateral hemi athroplasty in The Thrid Hopstial of Hebei Medical University from 2015-08 to 2017-01 was consisted in this study.17 of them were operated through the anterior laterior approach,and the rest of them were operated through the posterior laterior approach.The occurance of the osteo-line was recorded.All these patients were requested to take a AP view of postoperative plevis radiograph,then we recored the difference of length between the postoperative leg and the normal leg.Results:1 result of the observation and measurementAll of these 64 specimens have the back osteo-line,while the front ostoe-line occur in 59 specimens.The occurance ratio of the osteo-ine is 100%on the back and 92.18% on the front.64% of the front osteo-line is type A,28% of the front osteo-line is type B and 8% of the front osteo-line is type C.25% of the back osteo-line is type A,75% of the back osteo-line is type B,type C doesn’t exist on the back.The average of "a" is 18.46±2.67 mm.The average of "b" is 18.19±1.84 mm.The average of "c" is 11.37±2.32 mm.And respectively the distance between the line and the less trochanter tip is11.62±3.15 mm in the front and 11.37±2.32 mm in the back.2 result of clinical use of these osteo-lineOnly one of these patients operated through the anterior laterior approach was not found the osteo-line.All of the patient who operated through the posterior laterior approach have an osteo-line.And the osteo-line was much clear than that on those specimens.In AP view of the postoperative plevis radiographs,there were 6 shows an over 10 mm leg length discrepancy.Two of the six were operated through the anterior laterior approach,and four of the six were operated through the posterior laterior approach.The average of the leg length discrepancy was through anterior laterior approach is 4.47±5.47 mm.The average of the leg length discrepancy was through posterior laterior approach is 2.47±5.14 mm Leg lengthing take the advantage.Conclusion: The results showed that the occurcance ratio of the osteo line is high.And it was just 1.25±0.25 mm above the less trochanter at the medial of the femur.Using this osteo-line will make the operation more simplifued.This technology is easy to learn.It has a nature of easy popularization.With the progress of this technique individualization osteotomy will be used in the futhre.It could provide reliable basis for clinical application.