The Direct Anterior Approach (DAA) as a Standard Approach for Total Hip Arthroplasty (THA) in Coxa Profunda and Protrusio Acetabuli? A Radiographic Analysis of 188 Cases

Endoscopic Arthroplasty via Mini-open Direct Anterior Approach Improves Postoperative Complications and Acetabular Components of Total Hip Arthroplasty in Obese Patients

To overcome the high-risk complications and poor alignment of acetabular components in obese patients associated with direct anterior approach (DAA) for total hip arthroplasty (THA), we innovated an endoscopic arthroplasty via mini-open direct anterior approach technique (Endo-DAA). The purpose of this study was to compare the clinical and radiographic outcomes in obese patients subjected to THA between Endo-DAA, Bikini DAA, and conventional DAA. In this retrospective controlled study, a total of 360 consecutive primary THA on obese patients (body mass index greater than 28 kg/m2) via Endo-DAA, Bikini DAA, and conventional DAA performed from October 2017 to October 2022 by different surgeons and in a single center were included. Assessments including perioperative parameters, clinical outcomes, complications, and radiologic measurements were retrieved from patients before the surgery, perioperative period and the latest follow-up. A total of 360 consecutive THA (Endo-DAA = 108, Bikini DAA = 116, Conventional DAA = 136) with complete follow-up data were analyzed. Compared to Bikini DAA or conventional DAA, Endo-DAA significantly shortened the length of incision (5.46 ± 0.53), the duration of operation (64.47 ± 12.38), and postoperative hospital stay (2.15 ± 0.89). Endo-DAA significantly reduces wound related complications compared with conventional DAA. Besides, Endo-DAA achieved a significantly better alignment of acetabular components compared to Bikini DAA or conventional DAA. Furthermore, Endo-DAA improved postoperative pain at the activity at 24 h postoperatively and early functional scores. The Endo-DAA THA technique provides better short-term clinical and radiographic results in obese patients with a low rate of postoperative complications compared to Bikini DAA or conventional DAA.

Does Body Mass Index (BMI) Affect the Reconstruction of Biomechanical Parameters in Patients Undergoing Total Hip Replacement (THR) through the Direct Anterior Approach (DAA)?

OBJECTIVE

Direct anterior approach total hip replacement (DAA-THR) is gaining increased interest due to its tissue-sparing nature and rapid recovery. Obesity has been shown to be a significant parameter influencing cup positioning in DAA-THR. It was the intention of this retrospective study to examine how obesity would influence the restoration of native hip biomechanical parameters during DAA-THR.

MATERIALS AND METHODS

A total of 74 patients from a high-volume university orthopedic center after unilateral DAA-THA were included. Patients were retrospectively allocated to a study group (BMI > 30 kg/m2) and a control group (BMI < 30 kg/m2). Furthermore, propensity-score matching for baseline parameters was performed, leaving 30 patients in each group. Biomechanical parameters of the hip (i.e., femoral offset (FO), abductor lever arm (ABL), acetabular offset (AO), center of rotation (COR), stem alignment (SA), body weight lever arm (BWL), cup inclination (CI), and leg length discrepancy (LLD) were evaluated on standardized plain radiographs, and parameters were compared to the native contralateral hip.

RESULTS

Mean BMI in the study group was 35.07 ± 5.13 kg/m2 and 25.43 ± 2.64 kg/m2 in the control group. There was a significant decrease of the ABL only in the study cohort (p = 0.01). CI and SA did not differ between both cohorts. FO was slightly increased compared to the native hip in both groups. There was a marginally higher but non-significant proportion of improper FO restoration in the study group (19 vs. 16 patients, p = 0.60).

CONCLUSIONS

Obesity, as quantified by BMI, only has a limited impact on the adequate reconstruction of native biomechanical parameters of the hip during DAA-THR. ABL was the only parameter to be significantly decreased in the overweight patients after DAA-THR. Therefore, special care should be taken on proper acetabular reaming and consequent seating of the cup in the obese patient to avoid excessive lateral positioning.