Influence of patient-related characteristics on early migration in calcar-guided short-stem total hip arthroplasty: a 2-year migration analysis using EBRA-FCA

Abstract

BackgroundShort stems have gained popularity in recent years. Because of encouraging clinical results, indications have been expended from young to elderly and obese patients. However, long-term results are lacking. The purpose of this study was to evaluate the influence of gender, age, body weight, body mass index (BMI), and offset version on short-stem migration in correlation to the clinical outcome.MethodsThe implant migration of 202 metaphyseal-anchoring, calcar-guided short stems in 151 patients was assessed by “Einzel-Bild-Roentgen-Analyse” femoral component analysis (EBRA-FCA, femoral component analysis) in a 2-year follow-up. Full weight bearing was allowed directly after surgery. Patients were divided into groups regarding gender, age, body weight, BMI, and offset version. The Harris hip score (HHS) and satisfaction on visual analogue scale (VAS) were analyzed.ResultsAfter 2 years, mean axial subsidence of all 202 implants was 1.43 mm (standard deviation, SD 1.45 mm). A continuous reduction of initially pronounced subsidence over time could be observed. None of the stems had to be revised. Statistically significant increased rates of subsidence were seen in male (1.68 mm; SD 1.56 mm; p = 0.005) and heavy patients (1.54 mm; SD 1.48 mm; p = 0.022). No differences in implant migration were found regarding age, BMI, and different offset versions. HHS improved markedly from 45.8 (SD 15.9) to 98.1 (SD 4.7) while satisfaction on VAS improved from 1.8 (SD 2.2) to 9.7 (SD 0.9) after 2 years.ConclusionsThe results suggest a migration pattern with initially pronounced subsidence followed by subsequent stabilization. Male and obese patients show a slightly increased initial subsidence without any signs of sustained micromovement. No correlation was found concerning clinical results and pronounced initial subsidence above the threshold of 1.5 mm. No aseptic loosening or other signs of implant failure were seen within the observation period of 2 years.Trial registrationGerman Clinical Trials Register, DRKS00009834.

The learning curve in short-stem THA: influence of the surgeon’s experience on intraoperative adjustments due to intraoperative radiography

“…In the course of new developments in total hip arthroplasty (THA) over the last decade, short stems became increasingly popular [ 1 , 2 ]. Compared to conventional straight stems, new designs aim at conserving proximal bone stock and at allowing soft tissue sparing implantation [ 3 , 4 ].…”

Individualized Stem-positioning in Calcar-guided Short-stem Total Hip Arthroplasty

“…Excellent clinical results have led to successful usage of this technique in one-stage bilateral short-stem THA 2 . Ein-Bild-Roentgen-Analyses "femoral component analysis" (EBRA-FCA) of the presented implant have shown an increased initial axial subsidence especially in heavy and active male patients, given full weight bearing postoperatively, however, without any clinical consequences in the early stage 13 15 . Particularly stems that have been aligned in the valgus position result in increased early subsidence, but undersizing and insufficient cortical contact laterally, could be identified as the main cause 18 .…”

“…Several short-term results of the investigated short-stem have previously been published, mostly arising from an ongoing observational study at the author's institution 2 8 11 12 13 14 15 16 . Using the presented technique, the reconstruction of different femoro-acetabular offsets can be accomplished precisely 5 .…”

A Differentiated View on Short Stemmed Hip Arthroplasty – What are the Differences in Fixation and Biomechanics?

“…Clinically excellent results can be achieved by means of successful offset and leg length reconstruction [34,35]. Different studies on digital planning of short stems for different femoral neck geometries using various short-stem systems have shown particularly good results for partial femoral neck-preserving systems.…”