A Paradigm Shift in Managing Acute and Chronic Boutonniere Deformity
Authors: Merritt Wyndell H. , Jarrell Kathy 
Published: February 2020

Background
We have utilized relative motion splinting for early motion following acute repair of boutonniere injuries, and we have developed nonoperative orthosis-based therapy for the treatment of chronic injuries. We offer our early clinical experience using relative motion flexion splinting for boutonniere deformities and explain the anatomic rationale that permits immediate active motion and hand use following acute injury or repair. For chronic boutonniere deformity, we offer a nonsurgical management method with low morbidity as a safe alternative to surgery.

Methods
Our understanding of the extrinsic-intrinsic anatomic interrelationship in boutonniere deformity offers rationale for relative motion flexion splinting, which is confirmed by cadaver study. Our early clinical results in 5 closed and 3 open acute and 15 chronic cases have encouraged recommending this management technique. For repaired open and closed acutely injured digits, we utilize relative motion flexion orthoses that place the injured digits in 15° to 20° greater metacarpophalangeal flexion than its neighboring digits and otherwise permit full active range of motion and functional hand use maintaining the 15° to 20° greater metacarpophalangeal flexion for 6 weeks. In fixed chronic boutonniere cases, serial casting is utilized to obtain as much proximal interphalangeal extension as possible (at least −20°), and then relative motion flexion splinting and hand use is instituted for 12 weeks.

Results
Our acute cases obtained as good as, or better range of motion than, conventional management techniques, with early full flexion and maintenance of extension without any recurrences. The most significant difference is morbidity, with ability to preserve hand function during healing and the absence of further therapy after 6 weeks of splinting. Patients with chronic boutonniere deformity presented from 8 weeks to 3 years following injury (averaging 31 weeks) and were 15 to 99 years of age (averaging 42 years). All were serially casted to less than −20° (averaging −4°) and maintained that level of extension after 3 months of relative motion flexion splinting. All achieved flexion to their palm, and all met the Steichen-Strickland chronic boutonniere classification of “excellent.” There were no recurrent progressive boutonniere deformities in either acute or chronic cases and no instances of reflex sympathetic dystrophy/chronic regional pain syndrome (RSD/CRPS).

Conclusions
Relative motion flexion splinting affords early active motion and hand use with excellent range of motion achieved following acute open boutonniere repair or closed boutonniere rupture with less morbidity than conventional management. Chronic boutonniere deformity will respond to relative motion flexion splinting if serial casting can place the proximal interphalangeal joint in less than −20° extension, and the patient actively uses the hand in a relative motion flexion orthosis for 3 months, recovering flexion. No further therapy was needed in our cases. We believe this management technique should be attempted for chronic boutonniere deformity as a preferable alternative to surgery, which remains an option if needed.