Fitmore Versus CLS Stem in Total Hip Arthroplasty. Bilateral One-stage Operations

Summary

Main question: Will use of a stem design that allows anatomical reconstruction of the hip joint improve the outcome in terms of hip function and patient satisfaction without causing any adverse effects?

Background: Total hip arthroplasty with use of the most well documented implants is a safe and cost-effective procedure. In the Swedish Hip Arthroplasty register the CLS stem has a 16 years implant survival of 97, 5 %. It is a classic design which requires resection of most of the neck. The stem also intrudes into the greater trochanter which in patients with certain types of proximal hip anatomy makes proper introduction of the stem difficult. Finally it has a standard stem length which will jeopardise future stem removal should there occur any late infection or instability problems.

Short uncemented stems have been introduced to enable a more anatomic reconstruction of the hip joint and to cause less invasion of the femoral canal to facilitate future revision should it be necessary. A more conservative resection of neck could also be of value to improve the clinical outcome by improved hip function and patient satisfaction.

Purpose of the present study and design: In a prospective study the clinical outcome, stem fixation and bone remodelling around a short stem (Fitmore) will be studied. The main focus will be to evaluate patient reported outcomes especially concerning function, over all satisfaction, pain and activity. All patients will receive the same cup (Trilogy). This cup is chosen because it has a very thorough documentation in prospective RSA studies and in the Swedish hip arthroplasty register. All cups will be supplied with insert made of high molecular polyethylene (Longevity).

Number of hips in the study: 44 consecutive cases

Conditions

• Primary Hip Osteoarthritis
• Secondary Hip Osteoarthritis Due to Idiopathic Femoral Head Necrosis, Childhood or Inflammatory Disease
• Bilateral Hip Disease
• Surgical Treatment

Interventions

DEVICE

Total hip arthroplasty (Fitmore or CLS uncemented femoral stem made by Zimmer-Biomet, Warshaw, USA)

The most symptomatic side is randomised to one of the two stem types studied. If the patient has equal amount of symptoms on both sides, the one with most pronounced degenerative Changes on plain radiographs will be randomised. On the second side the type of stem not used on the first one will be inserted. All patients and allhip will receive the same type and design of cup.

Sponsors & Collaborators

• Zimmer Biomet

  collaborator INDUSTRY

• Sahlgrenska University Hospital

  lead OTHER

Principal Investigators

• Johan N Kärrholm, MD, Professor · Sahlgrenska University Hospital

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

35 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2011-03-17

Primary Completion

2026-06-30

Completion

2026-06-30