Figure 1. Anteroposterior radiograph AP of the right middle finger shows an avulsion fracture of the proximal phalanx at the PIP joint
Figure 2. Lateral view avulsion fracture of the proximal phalanx at the PIP joint
A 17-year-old adolescent presents with pain in the right middle finger after falling 2 days earlier. He was running and fell backward landing directly on the extended middle finger. The proximal interphalangeal (PIP) joint is swollen and he is unable to bend it more than 10 degrees. Radiographs of the right middle finger show an avulsion fracture of the proximal phalanx at the PIP joint (Figures 1 and 2). When stressing the PIP joint of the right middle finger, the joint opens up 40 degrees with valgus stress.
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The patient sustained an avulsion fracture of the radial collateral ligament of the PIP joint. The joint space remains stable and there is no evidence of joint subluxation on radiographs.
The digital collateral ligaments are critical in stabilizing the finger with axial forces and during opposing pinch stability. This is particularly true for the thumb and index finger. The radial and collateral ligaments of each finger combine with the volar plate to provide lateral stability.1
When the joint is stable on radiographs, a collateral ligament injury can be treated with early finger motion. Buddy taping the finger provides a dynamic splint that supports the injured collateral ligament. In general, the injured finger should be buddy taped to an adjacent finger for 3 to 4 weeks.1,2
The PIP joint can become stiff quickly with immobilization and this stiffness can become permanent. Thus, immobilization beyond 1 week with a finger splint should be avoided to prevent permanent loss of motion. PIP joint stiffness is a much more common complication than residual finger instability.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopaedics for Physician Assistants.
1. Freiberg A. Management of proximal interphalangeal joint injuries. Can J Plast Surg. 2007;15(4):199-203. doi:10.1177/229255030701500407
2. Freiberg A, Pollard BA, Macdonald MR, Duncan MJ. Management of proximal interphalangeal joint injuries. Hand Clinic. 2006;22(3):235-342. doi:10.1016/j.hcl.2006.05.003