Symax International Study

5 Year Clinical and Radiographic Follow-up of the Uncemented Symax Hip Stem in an International Study

The uncemented Symax hip stem is developed through optimization of the uncemented Omnifit hip stem. The Symax stem design combines an anatomical anteverted proximal geometry with a straight distal section. The proximal part is coated with a biomimetic hydroxyapatite (HA) coating for improved osseointegration to enhance load transfer and to minimize proximal bone loss. The distal part is treated with an anodization surface treatment in order to prevent distal bone apposition, which is expected to prevent distal loading and reduce proximal stress shielding. Aim of this study is to report mid-term clinical performance and evaluate whether the radiographic features are in line with the design principles of the Symax hip in an international clinical study with 5 years of follow-up.

Study Overview

• Status: Completed
• Conditions: Hip Osteoarthritis; Prosthesis Durability
• Intervention / Treatment: Device: Symax uncemented hip stem

• Study Type: Interventional
• Enrollment (Actual): 80
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Patients requiring uncemented primary total hip arthroplasty (osteoarthritis, avascular necrosis and/or post-traumatic arthritis), age between 18-70 years, BMI less or equal to 35.

Exclusion Criteria:

• Patients with bilateral hip complaints, impaired cognitive function and use of medication or illness influencing bone metabolism.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Other: Symax uncemented hip stem; The Symax hip stem is an uncemented design forged from Ti6Al4V alloy (Stryker EMEA). Primary mechanical stability is provided by anatomical metaphyseal geometry. The hip stem features a size dependent anteversion, neck length and offset, with a CCD angle of 128°. Secondary biological stability is accomplished by fast osseous integration due to the BONIT-HA coating on the metaphyseal part of the stem.

Device: Symax uncemented hip stem

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change of Harris Hip Score (HHS) during follow-up	A hip specific functional score	Preoperative HHS and postoperatively change in HHS at 6 months, 1 year, 2 years, 3 years and 5 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Radiographic evaluations	Radiographic evaluations per Gruen zone and comparison between two assessment teams	Immediately postoperative radiograhpic evaluation as baseline and changes in radiography at follow-up 6 months, 1 year, 2 years, 3 years and 5 years we evaluated the radiograhip evaluations again

Collaborators and Investigators

• Sponsor: Maastricht University Medical Center
• Collaborators: Vejle Hospital; Stryker Orthopaedics

Publications and helpful links

General Publications

• ten Broeke RH, Hendrickx RP, Leffers P, Jutten LM, Geesink RG. Randomised trial comparing bone remodelling around two uncemented stems using modified Gruen zones. Hip Int. 2012 Jan-Feb;22(1):41-9. doi: 10.5301/HIP.2012.9103.
• ten Broeke RH, Alves A, Baumann A, Arts JJ, Geesink RG. Bone reaction to a biomimetic third-generation hydroxyapatite coating and new surface treatment for the Symax hip stem. J Bone Joint Surg Br. 2011 Jun;93(6):760-8. doi: 10.1302/0301-620X.93B6.24986.
• Kruijntjens DSMG, Kjaersgaard-Andersen P, Revald P, Leonhardt JS, Arts JJC, Ten Broeke RHM. 5-year clinical and radiographic follow-up of the uncemented Symax hip stem in an international study. J Orthop Surg Res. 2018 Jul 31;13(1):191. doi: 10.1186/s13018-018-0888-9.

Study record dates

Study Major Dates

• Study Start (Actual): November 2, 2004
• Primary Completion (Actual): October 11, 2010
• Study Completion (Actual): October 11, 2010

Study Registration Dates

• First Submitted: January 15, 2018
• First Submitted That Met QC Criteria: March 16, 2018
• First Posted (Actual): March 19, 2018

Study Record Updates

• Last Update Posted (Actual): March 19, 2018
• Last Update Submitted That Met QC Criteria: March 16, 2018
• Last Verified: January 1, 2018

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Postoperative Complications; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Arthritis; Osteoarthritis; Osteoarthritis, Hip; Prosthesis Failure
• Other Study ID Numbers: METC 04-112

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No