The comparative anatomy of the minimally invasive total hip arthroplasty one incision method using the anterior and anterolateral approach

Abstract

The transformation in hip arthroplasty over the centuries is an evidence of the ingenuity in medicine. The evolution of hip arthroplasty is not only witnessed in the adaptation of the implantation devices, but is seen in the move from the large surgical incisions to the minimally invasive approach. This research investigated the anatomy underlying minimally invasive total hip arthroplasty when the anterior or the anterolateral approach were used. The anterior approach focused on the relation of the lateral circumflex femoral artery (LCFA) and the lateral femoral cutaneous nerve (LFCN) to various anatomical landmarks. The objective was to document whether any variations existed relating to the location and the branching pattern of the LCFA and the LFCN. The study assessed whether concerns relating to the LCFA and the LFCN, when the anterior approach was used had any merit. In the study, 90 hips were dissected for the anterior approach and 20 hips for the anterolateral approach. Simulations of the anterior approach surgical incisions were carried out by the orthopaedic surgeon on 21 hips. The anterolateral approach dissections focused on the relation of the superior gluteal vessels to the greater trochanter, anterior superior iliac spine (ASIS) and the incision site. The data collected was analysed using ANOVA with LSD and Bonferroni correction, in samples with three or more variables. Significant difference were detected for mean values from the pubic tubercle to the LCFA in the comparison of the samples 50 years and younger and those older than 50 years. In this group, p-value was also significant for the mean distances from the pubic tubercle to the straight head of the rectus femoris muscle. Statistical significance was found in the comparisons between male and female samples, the significant differences detected were for the comparisons per weight ranges and BMI. Findings made in the study included the average distance of the LFCN from the ASIS, these measurements were documented as 13.6 mm on the left side and 12.6 mm on the right side. In this study variations in the branching pattern and the area of origin of the LCFA were noted. In 82.2% the origin of the LCFA was found to be the profunda femoris artery, with 17.8% branching from the femoral artery. The branches of the LCFA were variable, with 15.6% branching into 4 arteries, 11.1% into 5 branches and 3.3% into 6 branches. The absence of the transverse branch was noted in 4.4% of the sample size. The LFCN was found coursing on the ASIS in 5.6% of the study sample. These findings are comparable to findings made in the studies by Dixit et al., (2001), Choi et al., (2007) and Prakash et al., (2010). The findings made in the study, detected no significant differences in measurements taken in relation to various anatomical landmarks and neurovascular structures, when anterolateral approach was used. The study findings prove that the concerns relating to the course and distribution pattern of the LFCN and the LCFA when the anterior approach was used, could be overcome when the anatomy of the hip joint and the thigh was understood. However, it is important to note the possible variations that exist in the course of the LFCN and the branching pattern of the LCFA.