Arthrodesis of distal interphalangeal (DIP) joints using headless compression screws for internal fixation is often used to relieve arthritis-related pain, instability, and deformity. New findings highlight important limitations in the broad use of this hardware in female patients and others with smaller bones. In women, 65 percent of small fingers and approximately 25 percent of women’s index and ring finger distal phalanges were too small to safely accommodate the 2.8 millimeter trailing thread diameter of commonly used commercially available cannulated compression screws.1 By contrast, less than 8 percent of male distal phalanges were too small for such screws. The findings are based on analysis of distal phalanges height and width from digital radiographs of 200 hands from 200 patients at Penn State Hershey Bone and Joint Institute.1
The lead investigator, Michael Darowish, M.D., explains, “Achieving DIP arthrodesis safely with headless compression screws in patients with smaller bones, particularly women, has been a concern, but the true extent of the issue wasn’t objectively investigated until now. That more than half of all female patients undergoing DIP arthrodesis may be affected is probably much greater than most surgeons would have guessed.”
Similar findings have also been described recently by other, independent groups of investigators using comparable techniques.2,3 In the Penn State Hershey study, distal phalangeal bone size was generally unrelated to age, although the largest diameter bones were seen in patients older than 75 years of age, and considered a possible result of arthritis-related hypertrophy.
Surgeons may need to routinely assess bone size pre-operatively, particularly in female patients and those with small fingers. When bones are too small for headless compression screws, alternative fixation approaches, including Kerschner wires (K-wires), intramedullary implants, tension band wires, or oblique placement of compression screws, should be considered.
“Although screws with a diameter as small as 1.8 millimeters are available, they are not cannulated, making precise positioning of the implant more challenging. Temporary K-wires are well-established for achieving fixation, but may protrude through the skin, increasing the risk of infection,” Darowish says. “My go-to choice for female patients with very small distal phalanges has been a shape memory intramedullary implant, which I have found to yield very good results, with few complications.”
Michael E. Darowish, M.D.
Assistant Professor, Orthopaedics and Rehabilitation
Orthopaedic Hand Surgeon
FELLOWSHIP: Hand surgery, Cleveland Combined Hand Fellowship, Cleveland, Ohio
RESIDENCY: Orthopaedic surgery, University of Rochester Medical Center, Rochester, New York
MEDICAL SCHOOL: University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
1. Darowish M, Brenneman R, Bigger J. October 2014. Dimensional analysis of the distal phalanx with consideration of distal interphalangeal joint arthrodesis using a headless compression screw. Hand. 10:100-104
2. Mintalucci D, Lutsky D, Matzon JL, et al. 2014. Distal interphalangeal joint bony dimensions related to headless compression screw sizes. J Hand Surg Am. 39:1068-1074.
3. Song JH, Lee JY, Chung YG, Park IJ. 2012. Distal interphalangeal joint arthrodesis with a headless compression screw: morphometric and functional analyses. Arch Orthop Trauma Surg. 132:663-9.