Dorsal Versus Volar Approach for CapFlex-PIP© Implantation

Study Overview
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Brief Summary
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The primary objective is to investigate the active extension six months after implantation of the CapFlex-PIP© arthroplasty, comparing the dorsal with the volar approach. This is a randomized controlled trial including 70 patients with PIP OA indicated for CapFlex arthroplasty.

Detailed Description
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The CapFlex-PIP© implant is a modular gliding surface proximal interphalangeal (PIP) joint prosthesis. For implantation, there are two approaches available: The dorsal central split approach according to Swanson and the volar approach described by Simmen. Our experiences and data from our prospective registry indicate, that the active extension of the PIP joint is better after the dorsal approach, but sometimes related with hyperextension of the PIP joint and secondary swan-neck deformity. Extension is supposed to be better after the volar approach, but associated with active and passive extension lag. Evidence of theses experiences will assist the surgeon in the preoperative planning to select the appropriate approach according to the patient's needs. The primary objective is to investigate the active extension six months after implantation of the CapFlex-PIP© arthroplasty, comparing the dorsal with the volar approach. This is a randomized controlled trial.

Official Title
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Dorsal Versus Volar Approach for CapFlex-PIP© Implantation: a Randomized Controlled Trial

Conditions
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Osteoarthritis

Intervention / Treatment
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* Procedure: Dorsal approach CapFlex arthroplasty
* Procedure: Volar approach CapFlex arthroplasty


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Indication for CapFlex-PIP© arthroplasty Patient aged 18 years and over Informed Consent as documented by signature Exclusion Criteria: Revision surgery CapFlex-PIP© arthroplasty at the thumb IP joint Major surgery at the same finger (e.g. DIP arthrodesis) Ulnar/radial deviation of the PIP joint > 15° Patients in which a reconstruction of the collateral ligaments has to be performed General medical contraindication to surgery German language barrier to complete the questionnaires Any disease process that would preclude accurate evaluation (e.g. neuromuscular, psychiatric or metabolic disorder) Pregnancy Surgery not planned by Dr. Herren, Dr. Schindele or Dr. Bodmer Legal incompetence

Ages Eligible for Study
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Minimum Age: 18 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: Dorsal approach CapFlex arthroplasty<br>Arthroplasty of the PIP joint with the CapFlex implant. Surgery will be done with the dorsal approach. | Procedure: Dorsal approach CapFlex arthroplasty<br>* Arthroplasty of the PIP joint with the CapFlex implant. Surgery will be done with the dorsal approach.<br>|
| Active Comparator: Volar approach CapFlex arthroplasty<br>Arthroplasty of the PIP joint with the CapFlex implant. Surgery will be done with the volar approach. | Procedure: Volar approach CapFlex arthroplasty<br>* Arthroplasty of the PIP joint with the CapFlex implant. Surgery will be done with the volar approach.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Active extension of the PIP joint measured with a goniometer |  | 6 months after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Subjective function using the Brief Michigan Hand Questionnaire (briefMHQ) |  | 6 months after surgery |