MIS THR using anterolateral approach – the game changer in Indian scenario, early functional and radiological outcomes

BACKGROUND: Minimally invasive surgery has become a trend in the last decade in all aspects of Orthopaedic surgery, including Total Hip Replacement. The debates and the interest generated in MIS THR is considerable and several approaches have been advocated. The potential benefits include lower surgical morbidity, less pain and peri-operative blood loss, quicker rehabilitation, shorter in-patient stay and improved cosmesis. On the other hand, deficient peer-reviewed literature, a steep learning curve, increased rate of complications due to inadequate visualization, component mal-position, neurovascular injuries, dislocation and intra-operative fractures have drawn criticism. OBJECTIVES: To present the various surgical tips and tricks and early functional and radiological results of MIS THR by anterolateral approach. STUDY DESIGNS & METHODS: The retrospective analysis of the records of patients undergoing Anterolateral MIS THR between January 2013 and January 2019 was the basis of this study. 72 hips of 70 patients were included in the study. The length of incision , duration of surgery, peri-operative blood loss, were studied. Functional assessment by Harris Hip Score, pain assessment by VAS score and radiological assessment for acetabular component and femoral stem positions were measured on plane X-rays. Data on preoperative and postoperative hemoglobin and hematocrit values, number of blood transfusions,time to ambulate as well as duration of hospital stay was studied. RESULTS: We had no major complications in the form of mortality, fatal Pulmonary embolism , temporary femoral nerve neuropraxia was seen in 1 case, component mal-position in 3 cases , superficial infection 1 case and a non displaced proximal femoral fracture line was evident on the early postoperative X-ray of 1 case. Functional assessment by Harris Hip Score (HHS )improved from pre-operative 42 (range:26-46) to postoperative 95 (range:72-98) at 1 yr. Radiologic analysis was carried out at post-operative 6weeks, 3months,6months and 1year. Femoral stem varus alignment was seen in 3 cases, Average Acetabular cup abduction angle was 43degrees (range: 40-55 degrees). Average acetabular cup ante-version angle was 17 degrees (range: 12-25 degrees). Of the 72hips, 64 were within the Lewinnek safe zone. The average postoperative hemoglobin value was 9.7 g/dl ( range: 8.5-12.3g/dl) and the average postoperative hematocrit value was 29.8% (range: 28.1-30.6%). CONCLUSIONS: The MIS anterolateral approach allows adequate exposure for component placement, less perioperative blood loss and pain in immediate post-op period , earlier discharge from hospital along with early return to function , good cosmesis with better patient satisfaction.