Proximal Tibial Open Wedge Osteotomy. A Clinical Prospective, Randomized RSA-trial.

Study Overview
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Brief Summary
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In the treatment of osteoarthritis of the medial compartment of the knee, Open wedge high tibial osteotomy is a good choice of treatment for the young and active patient. However it leaves an open gap which has to be filled with a bone substitute and requires stable fixation. Hitherto the golden standard has been autograft taken from iliac crest but there are donorsite related problems and limited amount available. Recently injectable and resorbable calciumphosphate-cements have been introduced and used with promising results in fractures of the distal radius, calcaneus and lateral tibial condyle. These new cements seem to be a good alternative to other bone substitutes providing high initial strength that might promote early mobilisation; it resorbs and promotes osteoconduction securing safe healing. The aim of the present study is to evaluate whether there is any difference in clinical outcome, correction, stability and healing in open-wedge osteotomies with three different bone substitutes: Autograft from iliac crest and the injectable calciumphosphate-cement Calcibon and as control a group with an empty gap. Osteosynthesis is performed with the Dynafix® system (EBI) The investigation is performed as a randomised prospective clinical trial including 45 patients with a planned 2 years follow-up period. Clinical outcome is evaluated with: Hospital of special surgery score, KOOS, SF 12 and Lysholm score. Routine standing x-rays is performed. Stability is assessed with Roentgen Stereophotogrammetric Analysis (RSA) that provides the opportunity of exact 3-dimensional measuring of eventual loss of correction. This combined with urine and serum bone-healing markers gives a very precise picture of the healing in the bone-gap. To asses the cartilage of the knee MRI is performed and biochemical markers fore Collagen type II degradation are measured.

Official Title
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Proximal Tibial Open Wedge Osteotomy. Stability and Healing Evaluated in a Clinical Prospective, Randomized Trial Using RSA.

Conditions
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Osteoarthritis, Knee

Intervention / Treatment
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* Procedure: bonesubstitution (Calcibon, Iliac Crest Bonegraft, control)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Osteoarthritis of medial compartment of the knee, Ahlbäck gr. 1-2 Candidate for proximal tibial medial open-wedge osteotomy Signed informed consent Exclusion Criteria: Prednisolone treatment. NSAID treatment. BMI > or = 35. Previous surgery in lateral knee compartment. Secondary Arthrosis following fracture(s) of the tibial condyle(s). Lack of informed consent.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1<br>Minced Iliac Crest autograft in osteotomysite | Procedure: bonesubstitution (Calcibon, Iliac Crest Bonegraft, control)<br>* Osteotomysite are filled with Calcibon (an injectable calcium phosphate cement) or Minced Iliac Crest Bonegraft og local graft as control<br>|
| Experimental: 2<br>Injectable calcium phosphate cement in osteotomysite | Procedure: bonesubstitution (Calcibon, Iliac Crest Bonegraft, control)<br>* Osteotomysite are filled with Calcibon (an injectable calcium phosphate cement) or Minced Iliac Crest Bonegraft og local graft as control<br>|
| Active Comparator: 3<br>Local autograft in the osteotomysite serves as control | Procedure: bonesubstitution (Calcibon, Iliac Crest Bonegraft, control)<br>* Osteotomysite are filled with Calcibon (an injectable calcium phosphate cement) or Minced Iliac Crest Bonegraft og local graft as control<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Migration in mm measured with RSA (Roentgen Stereometric Analysis) |  | postoperative, at 3 month, 1 and 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hip-Knee-Ankle axis |  | 3 month, 1 and 2 years. | 
| MR of the knee |  | 4 weeks preoperative, preoperative, at 1 and 2 years postoperative. | 
| Markers of chondral degradation |  | preoperative, at 6 weeks, 3 month, 1 and 2 years postoperative | 
| Markers of bone synthesis and degradation |  | preoperative, at 6 weeks, 3 month, 1 and 2 years postoperative | 
| Clinical scores: KOOS, Lysholm, SF12, Knee Score |  | Preoperatively, Postoperatively, 6 weeks, 3 months, 1 year and 2 years | 
| Histomorphometric evaluation of bone healing and osseous integration of cement |  | 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Osteoarthritis, Knee, Osteotomy, Healing, Roentgen Stereometric Analysis