The DePuy Proxima^™ Hip: A Short Stem for Total Hip Arthroplasty. Early Experience and Technical Considerations

Abstract

The rationale for short stems in cementless total hip arthroplasty (THA) is proximal load transfer and absence of distal fixation resulting in preserved femoral bone stock and avoidance of thigh pain. We report a consecutive series of 65 THAs inserted mainly for osteoarthritis with the DePuy Proxima hip, a short, anatomic implant with a pronounced lateral flare. Patients were assessed preoperatively and postoperatively at 3, 6 and 12 months and annually thereafter, using the Harris Hip Score (HHS), the Oxford Hip Score (OHS) and standard radiographs. No thigh pain was reported. Ata mean follow-up of 1.7 years the HHS improved from a preoperative mean value of 51 to 91 and the OHS decreased from a mean value of 42.5 to 12.4. Complications included 1 intraoperative fracture,1 superficial infection, and 3 deep vein thromboses. The proximal medial edge of the resected femoral neck appeared rounded off in 49 cases whilst in 16 cases a further loss of medial cortical density was observed. Patient selection and surgical technique are crucial factors contributing to a successful outcome. The surgical technique is different from standard THA.

A Short Tapered Stem Reduces Intraoperative Complications in Primary Total Hip Arthroplasty

“…There has been much evidence demonstrating standardlength, tapered, titanium, porous plasma-sprayed components perform well in the short, mid, and long term [10- recent interest in less invasive surgery through smaller incisions, shorter cementless stems have been popularized and utilized to achieve femoral fixation [15,24,40,56,62,66]. We therefore compared the intraoperative and perioperative complication rate, short-term survival, and preoperative and postoperative HHSs and LEAS scores for pain and function between groups receiving standardlength double-tapered stems and shorter, flat-wedge, ''microplasty'' tapered stems.…”

“…Short stems are thought to preserve more native host bone and optimize proximal load transfer, and while not a novel concept, they have become increasingly utilized with the advent of less invasive surgery and rapid-recovery protocols [15,24,40,56,62,66]. There are several proposed advantages of short stems, including easier insertion through smaller incisions and less invasive techniques, simpler femoral preparation with a ''broach only'' system, and their basic inherent bone-conserving nature allowing for more favorable conditions in the potential revision setting.…”

Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty

“…These features are claimed by the manufacturer to provide initial stability both vertically and rotationally and, together with a high horizontal neck resection, ensure load transfer to both the medial and the lateral aspects of the proximal femoral metaphysis (Walker et al 1999, Renkawitz et al 2008, Toth et al 2010). The macrotexture of the surface is stepped to increase ingrowth area and to transform tangential forces into compressive loads to the bone (Ghera and Pavan 2009). …”

CORR Insights®: Long-term Results and Bone Remodeling After THA With a Short, Metaphyseal-fitting Anatomic Cementless Stem

“…However, even theoretically sound design changes that received regulatory approval may occasionally be prone to unexpected adverse events that become apparent only after unrestricted clinical use, as illustrated by a number of recent examples including symptomatic taper corrosion and catastrophic modular neck failures [1,10]. The reported early outcomes with the newer generation of the metaphyseal-fitting stem studied by Kim et [2,6,12], and the currently available design may indeed provide additional benefits in terms of bone conservation, patient-reported outcomes, and/or superior ease of use for the surgeon. Nevertheless, there is no way to confirm definitively the comparative long-term survivorship of these stems at present, and all too often, by the time long-term data are available for a specific design, it has been removed from the market, and replaced by a newer and purportedly better product.…”