Working Diagnosis:
Radial Sagittal Band Rupture of right middle finger

Treatment:
Pt was placed in a Yoke splint(Sagittal band bridge) Case Photo #3 for 10 weeks.

Outcome:
At six weeks, she was able to flex and extend her finger without dislocation or subluxation of the extensor tendon.
The patient reported the sense of instability improved 4-5 weeks post injury.
In follow-up she had persistent swelling and was advised by the hand specialist this would take 12-13 months to resolve.
At last follow up patient was doing well.

Author's Comments:
Sagittal band ruptures lead to dislocation of the extensor tendon. This is also known as a Boxer's Knuckle as it is most commonly seen in boxers. Sagittal band ruptures most commonly affect the middle finger in professionals, and ring and little finger in amateurs. This case was interesting as this patient was a boxer 8-10 years prior but only an amateur.

Editor's Comments:
Saggital band rupture mechanism may be traumatic, or nontraumatic as in this case. Early identification may expedite treatment, and a careful physical exam visualizing the extensor tendon in flexion and extension can make the diagnosis. Dynamic ultrasound and MRI may confirm an injury or clarify milder injuries. These injuries may be classified as type 1 injuries which have no instability, type 2 injury with noted subluxation, and type 3 injuries with complete dislocation of the extensor tendon. The condition may also be associated with Rheumatoid arthritis, so evaluation for additional symptoms of joint swelling, stiffness, or rash would be prudent in this case. Injuries may be treated nonoperatively as described. Nonoperative treatment with splinting may be the initial approach, with immediate or delayed diagnosis. Consideration to early surgical repair may be appropriate for athletes whose activity would be significantly impacted by persistent symptoms. When discovered in the first 4-6 weeks, primary repair of the saggital band may be an option.
Delayed diagnosis may require reconstructive techniques. There is little evidence to note the best approach and is based upon case series and expert opinion. Therefore early referral to hand surgery in athletes with type 3 injuries to discuss early saggital band repair is reasonable, particularly in sports that require striking, weightbearing through the hands, or where persistent symptoms may cause an impairment to activities.

References:
Catalano, 3. R., Gupta, S., Ragland, 3. R., Glickel, S. Z., Johnson, C., & Barron, O. A. (2006, February). Closed treatment of nonrheumatoid extensor tendon dislocations at the metacarpophalangeal joint. Retrieved February 1, 2019, from https://www.ncbi.nlm.nih.gov/pubmed/16473685
Sagittal Band Rupture, What Do You See? No. 19. (2016, April 21). Retrieved February 1, 2019, from https://handlab.com/resources/sagittal-band-rupture/
Woon, C., MD. (2016, October 04). Sagittal Band Rupture (traumatic extensor tendon dislocation). Retrieved January 30, 2019, from https://www.orthobullets.com/hand/6029/sagittal-band-rupture-traumatic-extensor-tendon-dislocation?section=topic
Bents, R. T., Metz, J. P., & Topper, S. M. (2003, October). Traumatic extensor tendon dislocation in a boxer: A case study. Retrieved February 2, 2019, from https://www.ncbi.nlm.nih.gov/pubmed/14523299

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