The (Modified) Modified Brunelli Technique for Digital Flexor Tendon Repair, with Very Early Active Mobilization Rehabilitation Protocol

Background:
Rehabilitation after digital flexor tendon repair remains a challenging conundrum for hand surgeons. In recent years there have been major advances in postoperative protocols with an emphasis on controlled early active rehabilitation. These protocols in turn require robust flexor tendon repairs to withstand the rigors of active mobilization. While improvements have been shown in recovery times, range of motion and strength[i], there remains much continued interest in improving outcomes, particularly in Zone II injuries.

Aims:
We present our modified surgical technique for Brunelli volar pullout button repair of digital flexor tendons[ii], and demonstrate the safety and efficacy of using an aggressive postoperative active motion protocol.

Methods:
A retrospective analysis was performed on all patients for whom we performed zone I or II flexor tendon repair with the modified Brunelli technique and our own modifications (additional core suture and double-needle technique). Patients who underwent concurrent osteosynthesis or revascularization were excluded. Associated injuries, rehabilitation protocol and complications were recorded. Functional outcome was included when available. For appropriate patients, our very early active motion protocol was used.

Results:
Over a 15 month period, there were 66 patients who were operated on using the above technique. We excluded those with complex injuries as detailed above. Out of the remaining 51, 44 patients (ages ranging 14-70) were referred for very early active mobilization. There was one incident of tendon rupture 1 month post-op (patient who independently removed button within 2 weeks), and 1 late re-rupture (3 months postoperatively). There were 2 cases of infection, one of the surgical incision which required a surgical debridement, and one from a pressure sore under the button, which resolved with antibiotic therapy. 1 patient was lost to follow-up after button removal. Out of the patients who underwent very early active therapy and were available for review (including 3 FPL repairs) results were as follows: 64% (n=28) excellent, 16% (n=7) good, 7% (n=3) moderate, 7% (n=3) poor, and 7% (n=3) required additional surgery (re-repair or teno/arthrolysis).

Discussion:
In our experience this technique affords an exceptionally strong tendon repair, which in turn allows the therapist to perform a very aggressive rehabilitation protocol with confidence. From preliminary results, we have seen a low complication rate, with no early ruptures in compliant patients, and encouraging functional results. This series is limited by being a retrospective cohort, and lack of grip strength testing. Further research models to fully validate the functional outcomes will include a prospective cohort study with quantitative functional outcomes at set time periods, including grip strength testing and functional assessment questionnaires.

[i] Julianne W. Howell, Fiona Peck. Rehabilitation of flexor and extensor tendon injuries in the hand: Current updates. Injury 2013; 44 (3): 397-402
[ii] Giorgescu VG, Matei IR, Olariu MS. Zone II Flexor Tendon Repair by Modified Brunelli Pullout Technique and Very Early Active Mobilization. Journal of Hand Surgery 2019; 44(9): P804.e1-804.e6