Journal of Orthopedics & Muscular System Research

research article

9 Years Follow up of a Fully Covered Hydroxyapatite Femoral Stem

Daniel Godoy Monzon1*, Alberto Cid Casteulani2, Sebastian Sasaki2, Santiago Svarzchtein2

1Hospital Italiano de Buenos Aires, Hip Unit, Buenos Aires. Argentina

2Centro Medico Fitz Roy, Buenos Aires, Argentina

*Corresponding author: Daniel Godoy Monzon, Hospital Italiano de Buenos Aires, Presidente Peron 4190, Cp 1199, Argentina. Tel: +54-1149590200. Email: daniel.godoy@hospitalitaliano.org.ar

Received Date: 23 August, 2019; Accepted Date: 15 October, 2019; Published Date: 21 October, 2019

Abstract

Background: Total Hip Arthroplasty (THA) using uncemented stems is a popular practice in the last decades, with constant improvement in the area of stem designs and surface finish. The implant survivorship is critical and a less than 10% revision at 10 years is been proposed for many Registers and Guidelines for commercialization and use. The Element Novation Stem (Exactech, Gainesville, Florida, Usa) is an uncemented dual wedge stem fully covered with Hydroxyapatite (HA).

Objective: The study purpose is to report the minimum 9 years follow up results with the use of the Element Stem in primary THA in patients ranged 21 to 75 years.

Methods: Prospective study, patients aged 21 to 75 years, implanted with an uncemented dual wedge stem fully covered with HA and uncemented cup with Crosslink poly and 32 mm metal head, posterior approach with capsular reattachment and piriformis retention. One hundred and four consecutive patients (104 hips) were evaluated for a minimum 9 years after implantation. The mean follow-up period was 9.5 years. Harris Hip Score (HHS) and Merle d Aubigne Postel score preop and at final evaluation was recorded, patient satisfaction was evaluated, and all complications during follow up period were analized. The radiographic evaluation on sequenced control was recorded according to Engh’s criteria. And in case of radiolucent lines were detected, they were noted by Gruen zones on the femoral side. Dorr femoral shape was informing. Subsidence and stress shielding was also evaluated.

Results: One hundred and four THA in 104 patients were included in the initial serie, 54 females and 50 males (52%/48%). Follow-up of 9.5 years (range 9 to 10.2 years). Average age 56.8 years (range 42-75 years) at time of surgery. Clinical evaluation the Merle d’Aubigné Postel score improved 6.8 points and from the initial HHS 47.3 to 93.1 points at last follow up. Radiographic evaluation in 6 cases (5.3% at 3 months’ subsidence was detected, average 1.4 mm (range 0-2.6 mm) with no clinical manifestation, 3 cases of subsidence were associated to intraoperative fractures (1 greater trochanter and 2 in the calcar area, all resolved with wire cerclaje). At final evaluation 3 patients died with the THA in situ, 7 cases were revised, total survivorship was 93.3% considering all revision. Radiographic evaluation detected patients with radiolucent lines under close follow up, with no clinical relevance at final follow up. Stress shielding of more than grade 2 was observed in only three hips, which was non-progressive at one year after surgery.

Subjective Evaluation: 86 cases (82.6%) excellent, 9 patients (8.6%) good, 6 cases (5.9%), satisfactory and 3 cases (2.9%) poor. All poor results linked to the intraoperative complications.

Conclusions: The radiological results confirm the benefits of this type of stem with good osteointegration. The clinical and subjective results at medium term follow up are promising. With good surgical technical and without complications the risk of aseptic loosening should be absent or minimal.


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