Study to Evaluate Safety, of NextraTM in Surgery to Fuse the Proximal-interphalangeal- Joints
Condition: Foot Diseases
MeSH terms: Foot Diseases
Study type: Observational

Summary: 
      Hammertoe deformity is the most common deformity of the lesser toes. It primarily comprises
      flexion deformity of the proximal interphalangeal (PIP) joint of the toe, with hyperextension
      of the metatarsophalangeal (MTP).

      Etiologies of hammertoe deformity include a foot in which the second ray is longer than the
      first, MTP synovitis and instability, inflammatory arthropathies, neuromuscular conditions,
      and ill-fitting shoe wear. When a foot's second ray is longer than the first and shoe wear
      does not fit correctly, flexion of the PIP joint occurs to accommodate the shoe. This length
      difference also causes MTP synovitis to develop from overuse of the second MTP joint.
      Attenuation of the collateral ligaments and plantar plate result, and the MTP joint
      hyperextends and may even progress to dorsal subluxation or dislocation (see image below).
      Rheumatoid arthritis causes hammertoe deformity by progressive MTP joint destruction, leading
      to MTP joint subluxation and dislocation.

      With all 3 of these etiologies, the extensor digitorum longus (EDL) tendon gradually loses
      mechanical advantage at the PIP joint, as does the flexor digitorum longus (FDL) tendon at
      the MTP joint. The intrinsic muscles fire and sublux dorsally, as the MTP hyperextends. They
      now extend the MTP joint and flex the PIP joint, as opposed to their usual functions of
      flexing the MTP joint and extending the PIP joint.
    

Detailed description: 
      Device Description:

      Nextra implant is an anatomical 2-piece designed implant with 10° angulation with a locking
      fusion mechanism. The self-centering, metaphysis screw design allows a stable and secure
      relationship of the proximal and middle phalanges. The compression with progressive
      tightening approximates the bone surfaces for a controlled fusion.

      Pre-clinical Data:

      The Nextra Implant has been used to create fusions between the proximal and middle phalanges
      of the 2nd, 3rd. or 4th. toe.

      Clinical Experience:

      The NextraTM Implant has been used in humans as an implant to reduce hammertoe and
      contracture deformities.

      2. STUDY OBJECTIVES: The primary objective is to evaluate the post-market safety and
      performance of NextraTM in the reduction of post-operative pain symptoms in hammertoes and
      demonstrate the efficacy of the implant to securely stabilize bone surfaces to be fused as to
      be compared to K-wire fixation.

      3. STUDY DESIGN: General Design: Preoperative and post-operative factors will be assessed in
      the evaluation of efficacy and safety.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        This is a post market study and will consist of patients meeting the inclusion and
        exclusion criteria. The investigator recruits subjects if they meet the Inclusion/Exclusion
        requirements and are willing to sign an Informed Consent. Since the product is commercially
        available, randomization will occur at the time of surgery. Randomization will be according
        to a randomization table provided to the site investigators. The Surgeon will be unblended,
        and the subject will be blinded as to his/ her group (Treated-implant or Control-pin
        fixation).
      
Keywords: Hammertoe deformity; podiatry