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Collateral Ligament Injury of the Finger Interphalangeal (PIP and DIP) Joints
Understanding injuries to the collateral ligaments at the side of the finger’s interphalangeal (PIP and DIP) joints, and how they are treated.
What is a Collateral Ligament Injury of the Finger Interphalangeal Joints?
Each interphalangeal joint of the finger, the PIP joint in the middle of the finger and the DIP joint near the fingertip, has a collateral ligament on each side, radial and ulnar, that stabilises the joint against sideways force during grip and pinch. These ligaments are commonly injured by a jamming, twisting or side-on force to the finger, such as a ball striking an outstretched finger.
Either the ulnar collateral ligament (UCL) or the radial collateral ligament (RCL) can be affected, at either joint, and both are treated the same way. This is a different joint and ligament to the ulnar collateral ligament of the thumb, which is injured differently and treated on its own page.
Finger IP Joint Collateral Ligament Injury at a glance
What is it?
A sprain or tear of one of the paired collateral ligaments that stabilise the side of a finger's PIP or DIP joint
Common symptoms
Pain and swelling at the side of the joint, tenderness over the ligament, and instability with side-to-side stress
Who it affects
People who jam, twist or sustain a side-on force to a finger, commonly during ball sports
Is it serious?
Most sprains settle with splinting, but a complete tear with instability may need surgery to avoid a stiff or unstable joint
Treatment options
Buddy taping or splinting for partial tears, or surgical repair for complete tears with instability
First step
An examination and imaging to determine which ligament is affected and how severe the tear is
Symptoms and how finger IP joint collateral ligament injuries present
The main symptoms are pain and swelling at the side of the affected joint, with tenderness directly over the injured ligament. Grip and pinch can be painful, and a complete tear may leave the joint feeling unstable or wobbly with side-to-side stress. Because a jammed finger is common and often minor, ongoing swelling, instability or difficulty straightening the finger after the initial injury are the signs that warrant a closer look.
Causes and risk factors for finger IP joint collateral ligament injuries
- Ball sports injuries (a ball striking an outstretched finger)
- A jammed or stubbed finger
- Forceful sideways bending of the finger
- A fall onto an outstretched finger
- Direct trauma to the side of the finger
How are finger IP joint collateral ligament injuries diagnosed?
Diagnosis involves examination, including gently stress testing the joint to check for sideways movement and comparing it with the equivalent joint on the other hand, along with an x-ray to check for an associated small avulsion fracture. Ultrasound is occasionally used to assess the extent of the tear.
The diagnosis also considers whether the ligament itself has ruptured, which generally involves the ligament pulling off its insertion to the bone, or whether the bone it inserts into has broken. The latter injury is technically a fracture, because the part that needs to heal is a broken bone. The mechanics of the joint instability is the same, but the treatment and rehabilitation varies according to the specific nature of the injury.
Treatment options for finger IP joint collateral ligament injuries
Partial tears without instability are routinely treated successfully with buddy taping or a splint under the guidance of a hand therapist, allowing the ligament to heal in position while preserving joint movement. The duration of splinting and time to return to full activity varies according to the severity of the initial injury and your response to treatment.
Complete tears with instability, particularly where the joint is grossly unstable or a large avulsion fragment is displaced, may need surgical repair or reconstruction to restore stability and reduce the risk of chronic instability or early arthritis.
When to see a hand surgeon about finger IP joint collateral ligament injuries
A jammed finger that remains swollen, unstable or difficult to straighten beyond a week or two, or that shows an obvious deformity or a large avulsion fragment on x-ray, should be assessed by a hand surgeon.
What to expect at your finger IP joint collateral ligament injury appointment
At your appointment, Dr Tomlinson will examine your finger, including stress testing the joint, and arrange imaging as indicated. Together you will discuss whether splinting, buddy taping or surgery is the right treatment for your injury. If you have not already been seen by a hand therapist you will be provided with a referral to one.
Frequently Asked Questions
What is a collateral ligament injury of the finger IP joints?
Each finger’s PIP and DIP joints have a collateral ligament on each side, radial and ulnar, that stabilises the joint against sideways force. These ligaments are commonly sprained or torn by a jamming, twisting or side-on force to the finger, most often during ball sports.
What causes it?
The most common causes are ball sports injuries, a jammed or stubbed finger, a fall onto an outstretched finger, and any forceful sideways bending of the finger.
What can I do myself?
A jammed finger that remains swollen, unstable or difficult to straighten beyond a week or two, or shows an obvious deformity, should be assessed by a hand surgeon rather than managed with rest alone.
What can a hand therapist do?
Partial tears without instability are routinely treated successfully with buddy taping or a splint under the guidance of a hand therapist, allowing the ligament to heal in position while preserving joint movement.
What can a hand surgeon do?
Dr Tomlinson will examine your finger, including stress testing the joint, and arrange imaging as indicated. Complete tears with instability may need surgical repair or reconstruction to restore stability.
What can I expect from treatment?
At your appointment, Dr Tomlinson will examine your finger and arrange imaging as indicated. Together you will discuss whether splinting, buddy taping or surgery is the right treatment. If you have not already been seen by a hand therapist, you will be provided with a referral to one.
What happens if it's left untreated?
An untreated complete tear can lead to chronic joint instability, deformity and a higher risk of early arthritis, which is why ongoing swelling or instability after a jammed finger should be assessed rather than assumed to be a simple sprain.
Related conditions and treatments
These ligaments stabilise the finger’s PIP and DIP joints, and often co-exist with a volar plate injury. For the equivalent injury at the base knuckle (MCP) joint of the finger, see collateral ligament injury of the finger MCP joints. For the equivalent injury at the thumb’s main knuckle joint, see ulnar collateral ligament rupture of the thumb. A fracture at the base of the finger bone can occur alongside this injury, see hand fractures.