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Response to “Reattachment of Flexor Digitorum Profundus Avulsion: Biomechanical Performance of 3 Techniques”
1716
LETTERS TO THE EDITOR
Response to “Reattachment of Flexor Digitorum Profundus Avulsion: Biomechanical Performance of 3 Techniques” To the Editor: We congratulate the authors on an interesting article comparing novel repair methods of flexor digitorum profundus (FDP) avulsion injury using cadaveric models.1 Several different repair techniques have been introduced and refined over the years. Despite advances in surgical techniques, results tend to be relatively poor. Indeed, only about 50% of patients achieve either good or excellent outcomes.2 However, problems associated with poor outcome after repair of closed rupture or avulsion of FDP relate more to reduced distal interphalangeal joint (DIPJ) range of movement or flexion contracture than to rupture.2,3 Early active motion has been shown to improve outcomes4 and the authors of this study sought to find a stronger repair to allow this to take place. The authors of this study estimate that the minimum repair strength for active rehabilitation is 75 N based on estimations of friction, swelling, and decreased repair strength from biological response. In vivo studies have shown forces exerted on FDP during passive and active motion to be 15 and 28 N, respectively.5 Brustein et al6 showed that 2 micro anchors in a 4-strand repair had a force to failure of 69 N. The strengths of repairs achieved with incorporation of the volar plate exceed 150 N; although impressive, this is greatly in excess of what is necessary for early mobilization. Because current repair techniques allow for active mobilization with a rupture rate of 0% in many reported studies3 and the unsatisfactory outcomes reported after repair of FDP avulsions appear to be more related to DIPJ flexion contracture and stiffness, it would appear
to us that the focus needs to be on improving the rehabilitation regimes. The repairs currently on offer appear to be associated with an adequate breaking strength; the technique proposed by Brar et al1 confers a strength of repair that is greatly in excess of the requirements to allow mobilization, violates the DIPJ, and in our view has the potential to exacerbate the problem of DIPJ flexion contracture and stiffness. Stephen F. Murphy, MB BCh, MCh* Niall M. McInerney, MB BCh, MD* Michael O’Shaughnessy, MMedSc, MD* *Department of Plastic Surgery Cork University Hospital Cork, Ireland http://dx.doi.org/10.1016/j.jhsa.2015.02.035 REFERENCES 1. Brar R, Owen JR, Melikian R, Gaston RG, Wayne JS, Isaacs JE. Reattachment of flexor digitorum profundus avulsion: biomechanical performance of 3 techniques. J Hand Surg Am. 2014;39(11):2214e2219. 2. Moiemen N, Elliot D. Primary flexor tendon repair in zone 1. J Hand Surg Br. 2000;25(1):78e84. 3. Huq S, George S, Boyce DE. Zone 1 flexor tendon injuries: a review of the current treatment options for acute injuries. J Plast Reconstr Aesthet Surg. 2013;66(8):1023e1031. 4. Trumble TE, Vedder NB, Seiler JG III, Hanel DP, Diao E, Pettrone S. Zone-II flexor tendon repair: a randomized prospective trial of active place-and-hold therapy compared with passive motion therapy. J Bone Joint Surg. 2010;92(6):1381e1389. 5. Schuind F, Garcia-Elias M, Cooney WP, An KN. Flexor tendon forces: in vivo measurements. J Hand Surg Am. 1992;17(2):291e298. 6. Brustein M, Pellegrini J, Choueka J, Heminger H, Mass D. Bone suture anchors versus the pullout button for repair of distal profundus tendon injuries: a comparison of strength in human cadaveric hands. J Hand Surg Am. 2001;26(3):489e496.
ERRATUM
In the article by Wang WL, Darke M, Goitz RJ, Andrews CL, and Fowler JR in the July 2015 issue of the Journal (“A Comparison of Plain Radiographs and Computed Tomography for Determining Canal Diameter of the Distal Phalanx”), William L. Wang’s degree should have been BBA. We apologize for the error.
J Hand Surg Am.
r
Vol. 40, August 2015
LETTERS TO THE EDITOR
Response to “Reattachment of Flexor Digitorum Profundus Avulsion: Biomechanical Performance of 3 Techniques” To the Editor: We congratulate the authors on an interesting article comparing novel repair methods of flexor digitorum profundus (FDP) avulsion injury using cadaveric models.1 Several different repair techniques have been introduced and refined over the years. Despite advances in surgical techniques, results tend to be relatively poor. Indeed, only about 50% of patients achieve either good or excellent outcomes.2 However, problems associated with poor outcome after repair of closed rupture or avulsion of FDP relate more to reduced distal interphalangeal joint (DIPJ) range of movement or flexion contracture than to rupture.2,3 Early active motion has been shown to improve outcomes4 and the authors of this study sought to find a stronger repair to allow this to take place. The authors of this study estimate that the minimum repair strength for active rehabilitation is 75 N based on estimations of friction, swelling, and decreased repair strength from biological response. In vivo studies have shown forces exerted on FDP during passive and active motion to be 15 and 28 N, respectively.5 Brustein et al6 showed that 2 micro anchors in a 4-strand repair had a force to failure of 69 N. The strengths of repairs achieved with incorporation of the volar plate exceed 150 N; although impressive, this is greatly in excess of what is necessary for early mobilization. Because current repair techniques allow for active mobilization with a rupture rate of 0% in many reported studies3 and the unsatisfactory outcomes reported after repair of FDP avulsions appear to be more related to DIPJ flexion contracture and stiffness, it would appear
to us that the focus needs to be on improving the rehabilitation regimes. The repairs currently on offer appear to be associated with an adequate breaking strength; the technique proposed by Brar et al1 confers a strength of repair that is greatly in excess of the requirements to allow mobilization, violates the DIPJ, and in our view has the potential to exacerbate the problem of DIPJ flexion contracture and stiffness. Stephen F. Murphy, MB BCh, MCh* Niall M. McInerney, MB BCh, MD* Michael O’Shaughnessy, MMedSc, MD* *Department of Plastic Surgery Cork University Hospital Cork, Ireland http://dx.doi.org/10.1016/j.jhsa.2015.02.035 REFERENCES 1. Brar R, Owen JR, Melikian R, Gaston RG, Wayne JS, Isaacs JE. Reattachment of flexor digitorum profundus avulsion: biomechanical performance of 3 techniques. J Hand Surg Am. 2014;39(11):2214e2219. 2. Moiemen N, Elliot D. Primary flexor tendon repair in zone 1. J Hand Surg Br. 2000;25(1):78e84. 3. Huq S, George S, Boyce DE. Zone 1 flexor tendon injuries: a review of the current treatment options for acute injuries. J Plast Reconstr Aesthet Surg. 2013;66(8):1023e1031. 4. Trumble TE, Vedder NB, Seiler JG III, Hanel DP, Diao E, Pettrone S. Zone-II flexor tendon repair: a randomized prospective trial of active place-and-hold therapy compared with passive motion therapy. J Bone Joint Surg. 2010;92(6):1381e1389. 5. Schuind F, Garcia-Elias M, Cooney WP, An KN. Flexor tendon forces: in vivo measurements. J Hand Surg Am. 1992;17(2):291e298. 6. Brustein M, Pellegrini J, Choueka J, Heminger H, Mass D. Bone suture anchors versus the pullout button for repair of distal profundus tendon injuries: a comparison of strength in human cadaveric hands. J Hand Surg Am. 2001;26(3):489e496.
ERRATUM
In the article by Wang WL, Darke M, Goitz RJ, Andrews CL, and Fowler JR in the July 2015 issue of the Journal (“A Comparison of Plain Radiographs and Computed Tomography for Determining Canal Diameter of the Distal Phalanx”), William L. Wang’s degree should have been BBA. We apologize for the error.
J Hand Surg Am.
r
Vol. 40, August 2015