Effective proximal phalanx fracture fixation remains a cornerstone of modern hand surgery. Consequently, surgeons often choose between traditional cortical screws and newer intramedullary techniques. Although intramedullary screws (IMS) offer minimally invasive benefits, their rotational stability requires further investigation. Therefore, researchers conducted a biomechanical study to compare these methods under physiological loads.

Biomechanical Study Methodology

Researchers used eleven cadaveric hands to evaluate three distinct fixation constructs. Specifically, they examined single 3.5-mm IMS, dual crossing 2.5-mm IMS, and two 1.5-mm interfragmentary cortical screws. The team created sixty-degree oblique fractures and subjected them to a rigorous flexion-extension protocol. Furthermore, this simulation involved 2000 cycles at 0.25 Hz to mimic the stresses of postoperative motion. After testing, the study measured angular rotation and displacement in both coronal and sagittal planes.

Results in Proximal Phalanx Fracture Fixation

The results indicated that all three fixation methods provided similar levels of stability. In addition, the statistical analysis showed no significant differences in angular rotation or displacement between the groups. Similarly, the single IMS construct performed just as well as the more complex dual screw or cortical screw arrangements. Because of these findings, surgeons might consider IMS as a viable alternative for rotationally unstable fractures. Moreover, this technique potentially reduces soft tissue disruption while allowing for earlier mobilization.

Clinical Impact and Conclusions

Clinicians often prefer minimally invasive approaches to minimize postoperative stiffness. Consequently, the comparable stability of IMS makes it an attractive option for unstable fracture patterns. However, surgeons must still tailor the approach based on specific fracture morphology and bone quality. In conclusion, intramedullary screws offer a robust mechanical environment that supports early motion protocols and efficient healing.

Frequently Asked Questions

Is intramedullary screw fixation stable enough for early motion?

Yes, this study suggests that intramedullary screws (IMS) provide rotational stability comparable to traditional cortical screws, allowing for simulated early motion without significant displacement.

Which is better for short oblique fractures: one screw or two?

According to the biomechanical data, there were no statistically significant differences in stability between single IMS, dual crossing IMS, and dual cortical screw constructs.

Disclaimer: This content is for informational and educational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Refer to the latest local and national guidelines for clinical practice.

References

1. Zeng F et al. Comparing Fixation Stability of Rotationally Unstable Proximal Phalanx Fractures: A Biomechanical Study. Hand (N Y). 2026 Feb 20. doi: 10.1177/15589447261422504. PMID: 41719052.


2. Hall B et al. Fix the phalanx: A meta-analysis comparing intramedullary screws, pinning, plates, and lag screws for closed extra-articular proximal phalanx fractures. Hand Surg Rehabil. 2025 Dec;44(6):102524.


3. Orthobullets. Proximal Phalanx Fractures. Available at: https://www.orthobullets.com/hand/6032/proximal-phalanx-fractures.