Central Slip Injury Case Study: 19-year-old female with central slip injury to left ring finger

A 19-year-old female presented to Access Ortho. She had been playing in a netball carnival 3 weeks earlier and injured her finger when catching the ball. She had pain at the time of the injury and could not continue playing the game. She could not play any further games as the pain was causing difficulties catching the ball. The pain was in her knuckle (PIP – proximal interphalangeal joint). The patient reported she had injured the same finger approximately 5 years ago, and it had always been sensitive. 

A few days following the carnival, the pain had not changed, and the patient saw her GP. She had an X-ray that was reported as normal, so no treatment was initiated. After two weeks, the pain had not decreased, and there was visible swelling in the joint. The patient made an appointment with Access Ortho.

On initial assessment at Access Ortho, swelling of the left middle PIP joint on her ring finger and associated pain to this region were noted. The joint was stable, and she had full passive extension but limited flexion. A boutonniere deformity was noted. The patient was diagnosed with a central slip injury of the PIP. 

A splint was applied to keep the finger in extension and provide support. A referral was made for hand therapy to be started in 2 weeks. The hand therapist would advise on starting exercises to minimise stiffness, increase range of motion and assist with residual swelling. Access Ortho works closely with hand therapists located nearby. 

The patient was advised that, with these injuries, there can be long-term scarring and bulkiness in the joint; hence, strict adherence to a rehabilitation plan is important to reduce long-term complications. It was discussed with the patient that it was good that she sought orthopaedic advice, as often these injuries can be missed as they do not show on X-ray as the bone is not damaged. However, the long-term consequences of delaying treatment can be significant. 

The patient returned to Access Ortho for an appointment with the orthopaedic surgeon four weeks following their first visit. At this time, the patient had been attending hand therapy for two weeks. On assessment, the Orthopaedic Surgeon noted that the patient now had a full range of flexion and extension and that the boutonnière deformity noted on the initial assessment had resolved. 

The patient was advised not to participate in contact sports, such as netball, for another 4 weeks. She was also advised to wear a splint at night to maintain extension and to buddy strap (strap her finger to the adjacent finger) during the day to provide additional support when required. She was advised to continue exercises to maintain her finger range of movement.

The patient was advised that she may have a small amount of permanent residual swelling, as this is a common long-term complication with central slip injuries. The patient was not booked for further review but was advised to contact the clinic if she had any concerns. 

Central Slip Injury
A referral to hand therapy was made to assist the patient to regain movement and strength and decrease swelling following central slip injury.

What happens if a patient delays getting treatment for a central slip Injury?

Delaying treatment for a central slip injury can lead to complications. Here’s what you might expect if treatment is delayed:

  • Permanent Loss of Finger Extension: The PIP joint may lose the ability to fully straighten due to improper tendon healing.
  • Boutonnière Deformity: The PIP joint stays bent, and the DIP joint becomes hyperextended due to an extensor mechanism imbalance.
  • Joint Stiffness and Contracture: Prolonged immobility can cause permanent stiffness, limiting finger movement.
  • Tendon Retraction: A torn tendon may retract, complicating or preventing surgical repair.
  • Chronic Pain or Swelling: Ongoing inflammation can lead to persistent discomfort and swelling.
  • Weakened Grip: The injury may reduce hand strength and overall functionality.

Importance of Early Treatment

Early diagnosis and treatment (e.g., splinting, physiotherapy, or, in some cases, surgery) significantly improve outcomes. If you suspect a central slip injury (e.g., inability to extend the middle joint, swelling, or pain after trauma), seek medical advice promptly. Splinting the finger in extension is often required for several weeks to allow proper healing.

What is a Boutonnière deformity? 

A boutonniere deformity is a finger condition characterised by:

  1. Flexion of the Proximal Interphalangeal Joint (PIP): The middle joint in the finger becomes bent and stuck in a downward position.
  2. Hyperextension of the Distal Interphalangeal Joint (DIP): The fingertip joint is forced into an upward, overextended position.

Are central slip injuries often seen in netball players?

Netball is a high-impact, fast-paced sport that involves frequent ball handling, sudden changes in direction, and dynamic hand movements. These factors contribute to the potential for finger injuries, including central slip injuries

  1. Direct Trauma to the Finger

A common cause of central slip injuries in netball is the impact of the ball hitting the finger. If the ball strikes the extended finger at high speed, it can hyperflex the proximal interphalangeal joint (PIP), putting excessive strain on the central slip portion of the tendon.

  1. Forced Flexion Against Resistance

Attempting to catch or deflect a ball can forcefully bend the PIP joint while the finger is in an extended position. This sudden movement can overstretch or tear the central slip section of the tendon.

  1. Contact Injuries

Collisions with other players, particularly during contested passes, can lead to finger hyperflexion or trauma.