Clinical Research Of An Easy Method To Remove Femoral Head During Hip Replacement Procedure Of Femoral Neck Fractures

Objective：Surgeons always face the dilemma to remove femoral head of patients withfemoral neck fracture during hip procedure. Fragility fractures of femoral headwill often happen because of osteoporosis in the process of removal. Thetraditional removal methods may prolong operation time and cause boneresidual. In clinical we found out a simple method of femoral head, to study itsvalidity, we conducted the comparison research with traditional methods. Thereare few literatures on the report of femoral head removal technique.Methods:The study is divided into two parts: the clinical research and the screw pull-out strength experiment.Part I: Clinical Research:The same surgeon perform hip replacement procedure of femoral neckfractures, which were prospectively divided into two groups casually. Group A:conventional method with cork screw through neck fracture plane. Group B:new method group. First, a Steinmann pin was infixed at proximal third part ofthe femoral head to achieve control, then the femoral head was rotated out ofthe capsule, cork screw was inserted at the junction of head and neck, andfinally, the femoral head was taken out with Steinmann pin and cork screw holding together. The time from the revealing of head to complete removal wasrecorded.Part II: the screw pull-out strength experimentA screw pull-out strength experiment was done on the two groups ofremoved femoral head. Cork screw was inserted at the junction of head andneck in Group A, and at the neck fracture plane in Group B, then the screwpull-out strength was measured. TRAPEZIUMX software was applied to outputthe Fpullout and the graph of force and displacement.Results:From February2014to November2014,86old patients(female61, male25,age73±3.6) needing hip replacement with86cases of femoral neck fractures,who were prospectively divided into two groups casually. The mean time offemoral head removal was4.15min(sd1.65) in Group A and2.39min(sd0.86)min in Group B (p=0.025). The ratio of femoral head completely removedwas88.4%(38/43) in the conventional group and100%(43/43) in the newmethod group. Pull-out strength experiment display: Group A need mean907.61N (sd136.48), Group B need592.28N (sd60.55)(p=0.0006).Conclusions:1.Our mechanics experimental study shows that the bone intensity at thejunction of femoral head and neck is much better than in the femoral neckfracture plane. Stabilizing and revolving the femoral head by Steinmann pinfixation can get better revealing, make it easy to insert cork screw and revolve femoral head, increase extraction efficiency and integrity, and help to reducethe operation time, surgical trauma and bone residual risk, especially on the oldosteoporotic patients.2. Currently，there are many methods of removing the femoral head in theoperation, the cork screw is used by surgeon extensively.From our experimentswe can be see,in the surgery, the use of the improved method of removingfemoral head, whether in the first time, the number of handling and theintegrality is superior to the traditional method. It,s worth to apply for performerduring surgery, to reduce the operation time.3.The results of mechanical test provide us the exact data of the maximumpullout force when using the cork screw getting femoral head out from twodirections. The test proved that when screwing into the hardest bone at theadjacent of the femoral head and neck is better comparing to screwing into thecancellous bone of the femoral neck fracture, the former can gain greater betterholding force and more difficult to take the slip, This can provide furtherreference and help for the surgeons.