Radiographically comparison of femoral offset and leg length measurements in patients with hemiarthroplasty-applied femoral neck fractures

Femoral neck fractures – the prognosis and treatment choices of which vary according to age of the patient, level of the trauma and degree of displacement constitute an important mortal problem particularly for older population. In femoral neck fracture treatment of the older people, hemiarthroplasty is a worldwide accepted treatment method. Success of the surgical treatment is based on perfect placement of implant, which biomechanically and biologically optimizes the joint junction. Thanks to use of digital templating, the surgeon may determine which size of prosthesis he will use and where he will place it inside the bone, to ensure optimum post-operative function(3). The digital templating technique for total hip hemiarthroplasty operations applied in arthritic hips has been searched and its efficiency has been put forth by many authors. They are also often used by the surgeons. Nevertheless, the digital templating technique for hemiarthroplasty operations made after hip fractures has recently come to the agenda and limited number of researches is available on the matter in the literature. In this study, our aim is to radiographically measure and compare femoral offset and leg length values in both healthy and operated hips of the patients with femoral neck fractures whom hemiarthroplasty was applied in our clinic, to compare the results we achieved without digital templating with the results of hemiarthroplasty applied by using digital templating after femoral neck fractures and to search for requirement of preoperative modelling in hemiarthroplasty applications after femoral neck fractures. Out of 92 patients whom hemiarthroplasty was applied due to femoral neck fractures in the Orthopedics and Traumatology Clinic, Florence Nightingale, Bilim University between the dates 2012-2017, radiographies of only 40 patients fulfilling the necessary criteria for the research were involved in the study. Postoperative radiographies, whose obturator foramens are symmetrical, trochanter majors are lateral, and medial cortex borders are distinct, piriformis fossa are clearly observed, coccyx-pubis are uniplanar and that do not have contralateral hip joint arthrosis and do not have joint surgery either, were all involved in the measurement. In the evaluated radiographies, the cases where there is pelvic tilt; lower extremity is in abduction or adduction; trochanter major medial cortex is superposed; hip joint arthrosis and femur head sphericity disappeared were all considered as the criteria for non-involvement in the study and these radiographies were not taken into consideration. Out of 40 patients involved in our study; 15 (37.50%) patients are male and 25 (62.50%) patients are female. Age average of our patients is 80.83 ± 8.63 (min-max 58-97); age average of the male patients is 82.00 ± 9.53 (66-97); and age average of the female patients is 80.12 ± 8.17 (58-97). 19 (47.50%) of our patients had right hip operation; 21 (52.50%) of our patients had left hip operation. Cemented prosthesis was applied to 31 (77.50%) patients; 9 (23.50%) patients were applied cementless prosthesis. Calcar replacement prosthesis was used in 22 (55.00%) patients; calcarless prosthesis was used in 18 (45.00%) patients. In 6 (15%) patients, it was determined that the prosthesis was placed in varus position; additional pinning fixation was required in 3 patients 3 (7.50%). Garden type distribution consisted of Type 1:2 patients (5.00%), Type 2:9 patients (22.50%), Type 3:2 patients (5.00%) and Type 4:27 patients (67.50%). Pauwels type distribution consisted of Type 1:8 patient (20.00%), Type 2:7 patient (17.50%), Type 3:25 patient (62.50%). It was determined that femoral offset healthy side average value was 3.68±0.83 (2.51-5.3); femoral offset operated side average value was 3.17±0.62 (1.88-4.9). Femoral offset Healthy-Operated side difference average value was 0.52±0.93 (-1.81-2.54); and was statistically found as considerably lower (p=0.001). It was found that leg length healthy side average value was 3.45±0.79 (2.38-5.7); and leg length healthy side average value was 3.26±0.89 (1.58-6.35). The average difference between healthy leg and operated leg was found as 0.2±0.91 (-2.18-2.03); and statistically no considerable difference was found (p=0.174). The literature measured the difference between operated-healthy femoral offsets as -0.10±0.44. However, we measured the difference as 0.52±0.93 (-1.81-2.54). No considerable difference was statistically observed between our and literature groups femoral offset differences (p=0.385). Likewise, the literature measured the difference between the operated-healthy sides leg lengths as -0.25±0.85. However, we measured the difference as 0.20±0.91 (-2.18-2.03). Our group's leg length differences were statistically found to considerably be higher (p=0.049). Notwithstanding that in our study there is no statistically considerable difference between the operated side and healthy side in postoperative femoral offset measurements of the hemiarthroplasties carried out without digital templating, when compared to the cases in the literature where digital templating is made, the leg length was determined to considerably be longer. The digital templating is much more required for vertical offset measurements rather than femoral offset measurements.