Migration behaviour of 2 clinically excellent cementless stems with different design rationales: 5-year follow-up of a randomised RSA-study

Abstract

Introduction: Excellent long-term survival has been reported for both the Taperloc and the Mallory-Head cementless stems. However, little is known about the migration behaviour of these stems which have different design rationales. The purpose of this randomised clinical trial was to compare the migration and clinical outcomes of these stems during 5 years of follow-up. Methods: 42 consecutive hips in 38 patients scheduled to receive cementless THA were randomised to either a Taperloc or a Mallory-Head stem. Evaluation took place preoperatively and postoperatively on the second day, at 6, 12, 26, and 52 weeks, and annually thereafter. Primary outcome was stem migration measured using roentgen stereophotogrammetric analysis (RSA) and secondary outcomes were the Harris Hip Score (HHS) and 36-Item Short-Form Health Survey (SF-36). No patients were lost to follow-up; in 1 patient the THA was removed due to deep infection 3 months postoperatively. In 6 hips migration measurements were not possible due to insufficient marker configuration. Results: Throughout the follow-up period of 5 years, 3-dimensional migration was comparable between the Taperloc and the Mallory-Head stems ( p-values > 0.05). However, at the 5-year follow-up point the retroversion of the Mallory-Head stem was 0.9° more than the Taperloc stem ( p = 0.04). Initial subsidence and retroversion were respectively as large as 6.8 mm and 3.6° for the Taperloc stem and 5 mm and 3.6° for the Mallory-Head stem. After the first postoperative year, both implants had stabilised. The mean increment of HHS, as well as the SF-36 scores during the 5-year follow-up, were comparable between the 2 stems. Conclusions: The excellent long-term survival of both designs was confirmed in this study showing comparable initial migration with subsequent stabilisation. However, the Taperloc design with a flat, wedged geometry showed better rotational stability.

Radiostereometric analysis and clinical outcomes of a novel reverse total hip system at two years

“…This likely relates to the patients in that study being, on average, nearly a decade younger (mean age of 61 years) and healthier (mean BMI 27.8 kg/ m 2 ) in the paper by Nebergall et al 20 In larger samples of accepted dual-taper stems and uncemented acetabular components, the HHS and SF-36 PCS results appear to be at least equivalent. 21,23,28 While not definitive, this suggests that this device is a viable option for THA.…”

“… 20 In larger samples of accepted dual-taper stems and uncemented acetabular components, the HHS and SF-36 PCS results appear to be at least equivalent. 21 , 23 , 28 While not definitive, this suggests that this device is a viable option for THA.…”

“…11 The femoral component fixation appears to be at least equivalent to other well-established dual-taper stems both with and without hydroxyapatite coatings. [20][21][22][23] No individual patient demonstrated migration of concern. Acetabular component fixation is also consistent with clinically successful products.…”

Calcar-collar contact during simulated periprosthetic femoral fractures increases resistance to fracture and depends on the initial separation on implantation: A composite femur in vitro study

“…Although external rotation of the femur during a fall is a common mechanism, not all PFF with rotational mechanism are caused by internal rotation of the stem relative to the femur and surgeons should ensure that the ACC and PCC are both minimised to increase likelihood of CCC during all rotational injuries. Given that following insertion cementless femoral stems may subside 1mm along the anatomical axis of the femur during normal function in the first three months following implantation (Van Der Voort et al, 2021), we recommend that surgeons should aim to reduce any gap between calcar and under surface of the stem collar to a maximum of 1mm to increase the likelihood of protection against early post-operative PFF.…”

model-based radiostereometric analysis (RSA) randomized control trial evaluating the stability of the cementless Taperloc hip stem: the TapHip study

“…However, this data is based on the combined Taperloc THA designs. A recent RSA study conducted with the Taperloc showed a subsidence of 1.12 mm (SD 2.12) and a retroversion of 0.33° (SD 1.36) ( 13 ). The type of Taperloc used in the study is not specified.…”