Radiological positioning of a proximal interphalangeal joint resurfacing implant: Reliability and functional outcomes...

Area of Science:

• Orthopedic surgery
• Radiology
• Medical device evaluation

Background:

• Proximal interphalangeal (PIP) joint arthroplasty is a common procedure.
• Accurate assessment of implant positioning is crucial for optimal outcomes.
• Current methods for quantifying implant position may lack reliability.

Purpose of the Study:

• To define and assess the reliability of radiological measurements for CapFlex-PIP implant positioning.
• To investigate the correlation between implant position and patient outcomes (range of motion, function, pain) one year post-surgery.

Main Methods:

• Development of 7 radiographic measurements for proximal and distal CapFlex-PIP components.
• Analysis of 63 postoperative radiographs by two independent surgeons.
• Calculation of inter-rater reliability using intraclass correlation coefficient (ICC).
• Correlation analysis (Spearman's) between measurements and clinical outcomes (ROM, MHQ, pain).

Main Results:

• Only one of the seven measurements demonstrated good inter-rater reliability (ICC = 0.89).
• Other measurements showed poor to moderate reliability (ICC 0.34-0.69).
• No significant correlations were found between implant position measurements and ROM, MHQ scores, or pain (correlation coefficients 0.00-0.31).

Conclusions:

• Radiographic quantification of CapFlex-PIP implant position is unreliable.
• The lack of correlation suggests either measurement unreliability or minimal influence of implant position on outcomes.
• Further research is needed to refine measurement techniques or confirm the limited impact of implant positioning.