Cartilage disruption patterns associated with percutaneous intramedullary screw fixation for metatarsal fractures: a cadaveric study.

Purpose

Intramedullary screw fixation is an emerging technique for operative metatarsal fractures, yet the extent and location of articular cartilage disruption from retrograde screw insertion remain undefined. This study quantifies cartilage surface disruption and maps injury locations in the metatarsal head following screw placement.

Methods

Fourteen fresh-frozen cadaveric feet (56 lesser metatarsals) underwent standardized retrograde intramedullary screw fixation using 3.6 mm screws. Following dissection, the total articular surface area and cartilage defect were measured to calculate the percentage of disruption. The cartilage surface was divided into quadrants (dorsal-to-plantar) and thirds (medial-to-lateral) to determine screw trajectory.

Results

Mean cartilage disruption increased progressively from the 2nd to 5th metatarsals: 10.17%, 11.2%, 14.93%, and 17.43%, respectively. All screws were located within the middle third in the medial-to-lateral plane. In the dorsal-to-plantar plane, the majority of screws were positioned in the 2nd and 3rd quadrants. No screws were placed in the medial or lateral thirds.

Conclusion

Retrograde intramedullary screw fixation results in measurable cartilage disruption, with a tendency for screw placement in the middle third in the medial-to-lateral plane and 2nd and 3rd dorsal-to-plantar quadrants. While the relative cartilage surface disruption ranges from approximately 10% to 17%, increasing in more lateral metatarsals, the clinical implications remain unknown. These findings define the articular disruption of intramedullary screws in metatarsal fractures and highlight the need for future studies on the clinical outcomes after undergoing this fixation construct.