Several researchers have reported that imageless navigation is a reliable technique and results in more precise cup placement compared to conventional freehand techniques, however, few studies have been reported about the accuracy of the femoral stem placement. The primary aim of this study was to evaluate the precision of an imageless navigation system in measuring the limb length change. The secondary aim was to evaluate LLD following imageless navigation THA with modified registration technique in semilateral decubitus position. The authors reviewed 66 cases receiving cementless THA with imageless navigation from September 2013 to December 2014. The radiographic limb length change measured from pre-operative and post-operative digital x-ray was compared with the intraoperative calculation by the navigation system. Postoperative LLD in unilateral cases and second operation of staged bilateral cases were also recorded.Objective
Methods
The short stem prosthesis showed good results in patients with primary osteoarthritis. However, there were a few studies about the short stem THA in patients with osteonecrosis of the femoral head (ONFH). To evaluate the clinical and radiographic results of the short stem THA in patients with ONFH. The authors hypothesized that the short stem THA would be a promising procedure for patients with ONFH.Background
Objective
Navigated THA is a new procedure in Thailand that has been performed since 2012. The previous studies have reported that navigated THA was a safe, reliable procedure that resulted in a more consistent cup placement compared to the conventional free hand technique and decreased complications of THA, especially dislocation. Perioperative protocols are based on the surgeon's concern about stability of the prosthesis and the patient's health condition. Assuming that the navigator can improve the alignment and stability of THA, the time to start rehabilitation and the post operative length of stay should be reduced in the hospital that does not implement any perioperative protocols. The purpose of this study was to compare the time to start rehabilitation and the length of stay between navigated and non-navigated THA. This retrospective study of patients underwent THA using short stem by a single surgeon from March 2011 to November 2012. Seventy-six patients were classified into navigated and non-navigated groups. The patient's characteristic data that were recorded included age, sex, BMI, comorbid illness, diagnosis, ASA classification, preoperative hematocrit, operative time, type of anaesthesia, intraoperative blood transfusion, postoperative length of stay, postoperative complication and time to start rehabilitation. The data were compared between two groups by t-test and chi square test.Background
Methods
The accuracy of cup placement in navigated THA depends on the bony landmark registration intraoperatively. The usual patient position for registration is supine, but supine position has some drawbacks such as it's more difficult for femoral canal visualisation. The alternate patient position is lateral decubitus, but registration in this position may be unreliable because of the contralateral ASIS can't be palpated accurately. The other technique is registration in supine position first and then placing the patient in lateral decubitus for operation. The drawbacks of this technique are time consumption and increased risk of contamination. We created a semilateral decubitus position which combined the advantage of supine position for registration and lateral decubitus position for better femoral canal visualisation. We modified the registration technique by compressing the soft tissue above Pubic Symphysis(PS) to the abdomen and registered at the Antero-Superior-Pubic-Symphysis(ASPS). Evaluate the accuracy of cup placement within the “safe zone” and the accuracy of imageless navigation measurement by comparing the intraoperative values of acetabular cup abduction and anteversion to postoperative computed tomography (CT) values.Background
Objective
