Part 1: Series- Finger Joint Injuries and Extensor Tendon Ruptures/Sprains


The initial steps of management in finger injuries is highly important. Commonly the severity of injuries is ignored, decreasing the best outcomes of healing. Instead we should treat every ache and pain like a potential injury and learn to evaluate them for signs that we need help from our health care partner. This article focuses on the discussion of common tendon and ligament injuries of the finger and our self-care protocol for such.

It is common for visual signs of deformity to follow an injury to a finger joint or tendon. Long term swelling or abnormal size increases are common signs that an injury is present. Decreasing motion with splinting immediately is a common protocol for treating those injuries to help them to heal as best they can. But which ones do we splint and which ones do we keep moving while they heal?

The Basics of Anatomy: Finger joints and tendons.

Joint stability is provided for each joint of the finger by a dense interwoven connective tissue called the volar plate. Held with ligaments into this plate, each joint of the finger becomes stable unless used outside of its design.

On the top of each finger, a thick fibrous band runs out to the first joint of each finger, or the PIP (proximal interphalangeal joint) to extend it. The joint closest to the fingertip, the DIP (distal interphalangeal joint) is extended straight by two lateral bands on the back sides of each finger. Together, these extensor bands open each finger independently in a multitude of angles.

Once we understand the anatomy, we can better understand our injuries and their care. A complete understanding of your injury cannot be made by motion testing and visual inspection alone, if you heard a pop or snap or have swelling in the region with a lack of range of motion, it is highly recommended that you go in to your medical provider for films. Only from inspecting an X-Ray on 3 views (called a trauma series) can we fully see if you have a bony fracture and if your injury is in need of splinting.

Symptom:

-Pain on the back of the DIP joint.

-Deformity of the joint at rest (DIP joint).

-Inability to straighten the finger with pain on the back/top of the finger.

Possible Diagnosis:

-Central slip extensor tendon injury.

-Evulsion of the tendon from the bone

-Fracture of the bone with a fragment where the extensor tendon attaches.

A common injury, the extensor tendon either tears off the bone or breaks a bit of the bone off (an avulsion fracture). This injury will not heal itself and is one that we are choosing to highlight as one worth visiting your doctor for...

Creating instability, this truly needs surgical attention. If left alone, this injury might evolve into a boutonniere deformity which is a permanent deformity of the finger (as shown as our article cover photo). Besides the visual changes, the difference between the flexor tendon and extensor tendon strength make the athlete more prone to other injuries of the finger and hand as the overall integrity of the stability of the region is compromised.

Orthopedic Referrals:

More than 30% evulsion of the bone from the surface of the joint.

Difficulty extending your relaxed finger with aid. (AKA passive range of motion).

If the injury was sustained by a child. They still have open growth plates (this increases risk).

If a bony fragment is displaced on X-ray more than 2mm.