Effect of oblique headless compression screw fixation for metacarpal shaft fracture: a biomechanical in vitro study

Biomechanical study on fixation methods for horizontal oblique metacarpal shaft fractures

OBJECTIVE

To investigate differences in the effectiveness of two lag screws, a regular bone plate, and locking bone plate fixation in treating horizontal oblique metacarpal shaft fractures.

MATERIALS AND METHODS

Horizontal oblique metacarpal shaft fractures were created in 21 artificial metacarpal bones and fixed using one of the three methods: (1) two lag screws, (2) a regular plate, and (3) a locking plate. All the specimens were subjected to the cantilever bending test performed using a material testing machine to enable recording of the force-displacement data of the specimens before failure. The Kruskal-Wallis test was used to compare failure force and stiffness values among the three fixation methods.

RESULTS

The mean failure force of the two lag screw group (78.5 ± 6.6 N, mean + SD) was higher than those of the regular plate group (69.3 ± 17.6 N) and locking plate group (68.2 ± 14.2 N). However, the mean failure force did not significantly differ among the three groups. The mean stiffness value of the two lag screw group (17.8 ± 2.6 N/mm) was lower than those of the regular plate group (20.2 ± 10.5 N/mm) and locking plate group (21.8 ± 3.8 N/mm). However, the mean stiffness value did not significantly differ among the three groups.

CONCLUSION

The fixation strength of two lag screw fixation did not significantly differ from that of regular and locking bone plate fixation, as indicated by the measurement of the ability to sustain force and stiffness.

[Osteosynthesis by intramedullary headless screw in digital fractures: A retrospective scannographic and anatomical study]

INTRODUCTION

Long finger skeletal fractures are common injuries. In displaced forms, surgical treatment is required. With the advent of headless cannulated screws, the technique has been simplified and allows reduction in both planes. The objective of our study was to evaluate the functional recovery of patients operated on by this technique.

MATERIAL AND METHOD

We conducted a retrospective single-center study between 2019 and 2022. Eleven patients were followed and 12 fractures analyzed. A radio-clinical follow-up was carried out at 1 month then at the last follow-up with an evaluation of the articular amplitudes and a quality of life score (QuickDash, QD). The time to return to professional and sporting activities, pain (EVA) was collected. An anatomical/scannographic evaluation was performed to assess tendon and cartilage damage.

RESULTS

At the last follow-up, the average global flexion was 266° and the extension was total. An average QD score of 15.9 and a Jamar force of 106% compared to the healthy side were observed. The return to physical and professional activities was earlier and the pain quickly tolerable. No secondary displacement was objectified and all were consolidated at the last follow-up, without malunion. No patient had been operated on secondarily.

CONCLUSION

This technique seems to be a safe and non-traumatic. It allows a faster return to sports and professional activities with fewer complications and no need to remove the material.