The direct minimally invasive anterior approach (DMIAA) and the use of uncemented stems demonstrated an increase in intraoperative fractures in recent literature. Whether the different design of the stems additionally influences the incidence of perioperative local complications, was the goal of this study.
From January 2008 until June 2010, all patients undergoing primary cementless total hip arthroplasty, using a DMIAA, were consecutively included. The choice of the implant was defined by the day of operation. Age, gender, body mass index, type of prosthesis, and the practical experience of the performing surgeon were retrospectively analyzed. Of main interest were intraoperative fractures, postoperative hematoma, and wound healing.
Six hundred forty consecutive patients (64 years [18-94], 339 female, 53%, body mass index 26) have been included. A Quadra-H stem (Medacta) was used in 457 patients (71%). In 183 (29%) patients, a short stem designed for the DMIAA (130 Fitmore, Zimmer and 53 AMIStem, Medacta) was used. We counted 34 (5.3%) intraoperative fractures (16 at the greater trochanter, 18 proximal shaft fractures), 20 (4%) hematomas, and 8 (2%) wound healing problems. The standard length stem showed more local complications (11.8% vs 4.4%) (P = .014, odds ratio 1.63, confidence interval 1.1-2.4) and significantly more (6.8% vs 1.6%) intraoperative fractures (P = .027, odds ratio 1.98, confidence interval 1.1-3.6).
The standard length stem showed more perioperative complications, especially periprosthetic fractures. It seems that these implants not only put more stress to proximal osseous structures, but there might also be more traction and irritation to the soft tissue while preparing, resulting in more hematomas and wound healing problems.