Discrepancy of Trial Rasp and Femoral Stem Relative Position Within the Femoral Canal of a Coated Tapered System: An Intraoperative, Intrapatient Controlled Study.

BACKGROUND: For a successful total hip arthroplasty, the final position of the trial rasp should be adopted by the femoral stem to achieve correct positioning. This study aimed to characterize the discrepancy of the stem and rasp position in vivo of a widely used dual-tapered straight stem with rectangular cross section that is known to have an oversized stem with respect to the rasp. METHODS: The distances between the tip of the greater trochanter and the shoulder of the implant and rasp were measured on 39 intraoperatively acquired fluoroscopic image pairs. Leg-length discrepancy was also measured clinically before and after surgery. RESULTS: A paired t-test showed a significant average protrusion of the femoral stem with respect to the final rasp position of 2.63 mm (standard deviation = 2.3 mm, P < .001), while 88% of the cases had no leg-length discrepancy after surgery. The quantified stem protrusion was statistically significant but did not reach clinical relevance and was easily mitigated in our study. CONCLUSIONS: The quantified stem protrusion appears to be clinically manageable, as only 2 cases required attenuation of stem positioning: in one case by the use of a femoral head with a shorter neck and in the other case by rerasping the femoral bed. Neither case was associated with the most extreme differences in position of the stem with respect to the final rasp. In addition, the used stem shows good overall outcomes in other studies. It appears that factors other than stem and rasp position play a critical role to the surgeon and for total hip arthroplasty success.

Clinical Performance, Patient Reported Outcome, and Radiological Results of a Short, Tapered, Porous, Proximally Coated Cementless Femoral Stem: Results up to Seven Years of Follow-Up.

BACKGROUND: The primary aim of our study was to assess clinical performance, patient reported outcome and radiological results of cementless primary total hip arthroplasty using Tri-Lock Bone Preservation Stem. METHODS: Between March 2010 and June 2012, 163 consecutive patients, were enrolled in the study. Patients were assessed clinically and radiographically prior to surgery as well as at 6, 12, 24 months and then at 5, 6, and 7 years postoperatively. RESULTS: Using the Dorr classification, 39 patients (23.9%) were classified as Dorr A, 116 patients (71.2%) as Dorr B, and 8 patients (4.9%) as Dorr C. A total of 139 patients (85.3%) received a high offset, whereas 24 patients (14.7%) received a standard offset stem. Total Harris Hip Score of the patients increased from a mean of 27.29 (±4.6) preoperatively, upto 97.28 (±9.0) after 5 years. Mean preoperative Short Form-12 (SF-12) Physical Health Composite Scale score was 27.31 (±3.8). After 5 year was 55.3 (34-57). The mean preoperative SF-12 Mental Health Composite Scale score was 57.02 (±5.9). After 5 year was 59.3 (28.7-60.8). Only one patient underwent revision surgery for dislocation and revision of the head. CONCLUSION: Tri-lock Bone Preservation Stem DePuy proved to be an easy-to-use device. Results obtained up to 7 years of FU show excellent clinical performance, as well as radiographic osseointegration, with no cases of aseptic loosening and no images of progressive radiolucent lines or periprosthetic osteolysis.

Minimum 10 year survivorship analysis of a partially coated hydroxyapatite tapered femoral stem in elderly patients with an average age over 75.

This is a retrospective, non-comparative study of 212 consecutive patients who underwent Total Hip Arthroplasty with an uncemented hydroxyapatite (HA) coated stem system from November 1997 to March 2000. The objective of the study was to analyze the performance of the implant at a minimum of 10 years in older patients (mean age 79.6 years). The Kaplan-Meier survivorship of the femoral stem at 10 years was 100%, and 97.5% for the whole prosthesis. The mean Merle d'Aubigné clinical score improved from 4.4 ± 2.1 points pre-operatively to 13.39 ± 3.77 points at final follow-up (p<0.05), and the mean VAS score for thigh pain was 1.25. The radiographic analysis showed that there were no significant radiolucent lines or osteolysis compromising the fixation of the implant.