LETTERS TO THE EDITOR
Radioscaphoid Articulation Incongruity in Kienböck Disease To the Editor: We read with great interest the article by Kawanishi et al1 and commend the authors on their well-executed 3-dimensional analysis of carpals. They found that carpal collapse in Kienböck disease is not associated with dorsal translation of the scaphoid, as seen in patients with scapholunate advanced collapse (SLAC). Hence, the carpal collapse in Kienböck disease is not associated with early radioscaphoid joint incongruity. We were excited to read this article because it paralleled the outcome of an ongoing observational study at our institution involving patients undergoing proximal row carpectomy. In the past 2 years, we have performed proximal row carpectomy in 11 patients with advanced Kienböck disease and 6 patients with SLAC wrist. In all cases, we noted the condition of the articular surface of the lunate and scaphoid articular surfaces of the radius and proximal articular surface of the capitate. These were our observations: In 11 patients with advanced Kienböck disease (beyond stage 3B),2 the radioscaphoid articulation was spared from arthritis in all but 1. The lunate surface of the distal radius was eroded in 4 patients (Fig. 1) and capitate articular surface was eroded in 1. In six patients with SLAC wrist (5 were stage II and 1 was stage III),3 the lunate articular surface was preserved in all cases, but all had severe degeneration of the articular surface of the scaphoid articular surface of the radius. One patient had erosion of the articular cartilage of the capitate. Our observations support the analysis of Kawanishi et al1 and the concept that in Kienböck disease radioscaphoid articulation avoids incongruity for a long duration because the scaphoid does not translate dorsally. However, in SLAC wrist, because of dorsal translation of the scaphoid, early arthritis changes occur at the radioscaphoid joint.
FIGURE 1: Intraoperative photograph during proximal row carpectomy in a 36-year-old woman with Kienböck disease. The articular cartilage at the lunate articular surface was eroded (arrow) but the articular surface at the scaphoid articular surface was pristine.
Praveen Bhardwaj, MS S. Raja Sabapathy, MS Department of Plastic Surgery, Hand Surgery Reconstructive Microsurgery, and Burns Ganga Hospital Coimbatore, India http://dx.doi.org/10.1016/j.jhsa.2015.03.013 REFERENCES 1. Kawanishi Y, Moritomo H, Omokawa S, Murase T, Sugamoto K, Yoshikawa H. In vivo 3-dimensional analysis of stage III Kienböck disease: pattern of carpal deformity and radioscaphoid joint congruity. J Hand Surg Am. 2015;40(1):74e80. 2. Lichtman DM, Mack GR, MacDonald RI, Gunther SF, Wilson JN. Kienböck’s disease: the role of silicone replacement arthroplasty. J Bone Joint Surg Am. 1977;59(7):899e908. 3. Watson HK, Ballet FL. The SLAC wrist: scapholunate advanced collapse pattern of degenerative arthritis. J Hand Surg Am. 1984;9(3):358e365.
Letter Regarding “Biomechanical Analysis of Flexor Tendon Repair Using Knotted Kessler and Bunnell Techniques and the Knotless Bunnell Technique” To the Editor: We congratulate the authors on their work and publication in the field of barbed suture repair of
1266
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Ó 2015 ASSH
r
Published by Elsevier, Inc. All rights reserved.
digital flexor tendons.1 Indeed, hand caregivers continue to debate the ideal flexor tendon surgical technique, suture material, rehabilitation, and other aspects
1267
LETTERS TO THE EDITOR
of this challenging injury. We have also studied the use of barbed suture and found the concept appealing, among other reasons because of the potential for developing a knotless flexor tendon repair that could remove that known weak link in repair technique.2 Using porcine flexor digitorum tendons, the authors of this article compared biomechanical characteristics of 4 repair techniques.1 The first 2 groups served as controls and featured repairs using conventional Kessler and Bunnell sutures. Repairs in the final 2 groups were performed using the Bunnell technique with knotless barbed suture, with and without peripheral suture. Four core strands were used in all groups. The investigators evaluated the performance of each technique in static and dynamic testing. This well-designed study represents a step forward in the field because the authors evaluated the performance of barbed suture in a dynamic model, adding to the results of several prior static and load-to-failure studies. We think performance under dynamic stressing is a key concern for any barbed suture repair technique and may be more important to study for any flexor tendon repair than we previously realized. In current unpublished studies in our biomechanical laboratory, we have performed in situ repairs in zone II in cadaveric hands using bidirectional barbed suture in a manner similar to that described by previous authors. We have a simulated active range of motion apparatus that is able to apply alternating tension on the flexor and extensor tendons to bring the fingers through a full range of motion. We believe that subjecting repaired tendons to angular motion through the pulley system likely better approximates the forces encountered during early rehabilitation. Our current studies using this model are showing that the barbed suture repair technique that we are using fails early and catastrophically during this simulated active range of motion. This is in contrast to what we found during traditional single load-to-failure testing of barbed suture constructs. Our hypothesis is that the active range of motion simulation is causing
J Hand Surg Am.
the barbs to sequentially gain and lose purchase and leads to the gap formation and failure compared with a single tensile load that could allow the barbs to grasp and hold. We think this finding is important and we present it here to make other investigators or surgeons aware, who may want to study this suture technique further or even consider using it clinically. Also, based on what we are seeing with this model in our laboratory, we think it is probably important for all novel flexor tendon repair techniques to be tested cyclically in a manner that more closely represents early postoperative rehabilitation. The investigators in the current study found that their barbed suture technique was able to withstand cyclic loading. This may be because their suture technique is better suited to withstand early active range of motion than the techniques we have been studying in our laboratory, or it may be that their model did not recreate the cyclic forces experienced in vivo. In either case, we advocate continued study of barbed suture and all novel flexor tendon repair techniques in a manner that closely mimics in vivo conditions during postoperative rehabilitation as best as possible before clinical adoption. As the authors noted, their study should serve as a guide to further biomechanical and, eventually, in vivo studies. Frederick P. O’Brien III, MD Brent G. Parks, MSc Kenneth R. Means, Jr, MD Curtis National Hand Center MedStar Union Memorial Hospital Baltimore, MD http://dx.doi.org/10.1016/j.jhsa.2015.02.034 REFERENCES 1. Jordan MC, Schmidt K, Meffert RH, Hoelscher-Doht S. Biomechanical analysis of flexor tendon repair using knotted Kessler and Bunnell techniques and the knotless Bunnell technique. J Hand Surg Am. 2015;40(1):115e120. 2. Parikh PM, Davison SP, Higgins JP. Barbed suture tenorrhaphy: an ex vivo biomechanical analysis. Plast Reconstr Surg. 2009;124(5): 1551e1558.
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Vol. 40, June 2015
Radioscaphoid Articulation Incongruity in Kienböck Disease To the Editor: We read with great interest the article by Kawanishi et al1 and commend the authors on their well-executed 3-dimensional analysis of carpals. They found that carpal collapse in Kienböck disease is not associated with dorsal translation of the scaphoid, as seen in patients with scapholunate advanced collapse (SLAC). Hence, the carpal collapse in Kienböck disease is not associated with early radioscaphoid joint incongruity. We were excited to read this article because it paralleled the outcome of an ongoing observational study at our institution involving patients undergoing proximal row carpectomy. In the past 2 years, we have performed proximal row carpectomy in 11 patients with advanced Kienböck disease and 6 patients with SLAC wrist. In all cases, we noted the condition of the articular surface of the lunate and scaphoid articular surfaces of the radius and proximal articular surface of the capitate. These were our observations: In 11 patients with advanced Kienböck disease (beyond stage 3B),2 the radioscaphoid articulation was spared from arthritis in all but 1. The lunate surface of the distal radius was eroded in 4 patients (Fig. 1) and capitate articular surface was eroded in 1. In six patients with SLAC wrist (5 were stage II and 1 was stage III),3 the lunate articular surface was preserved in all cases, but all had severe degeneration of the articular surface of the scaphoid articular surface of the radius. One patient had erosion of the articular cartilage of the capitate. Our observations support the analysis of Kawanishi et al1 and the concept that in Kienböck disease radioscaphoid articulation avoids incongruity for a long duration because the scaphoid does not translate dorsally. However, in SLAC wrist, because of dorsal translation of the scaphoid, early arthritis changes occur at the radioscaphoid joint.
FIGURE 1: Intraoperative photograph during proximal row carpectomy in a 36-year-old woman with Kienböck disease. The articular cartilage at the lunate articular surface was eroded (arrow) but the articular surface at the scaphoid articular surface was pristine.
Praveen Bhardwaj, MS S. Raja Sabapathy, MS Department of Plastic Surgery, Hand Surgery Reconstructive Microsurgery, and Burns Ganga Hospital Coimbatore, India http://dx.doi.org/10.1016/j.jhsa.2015.03.013 REFERENCES 1. Kawanishi Y, Moritomo H, Omokawa S, Murase T, Sugamoto K, Yoshikawa H. In vivo 3-dimensional analysis of stage III Kienböck disease: pattern of carpal deformity and radioscaphoid joint congruity. J Hand Surg Am. 2015;40(1):74e80. 2. Lichtman DM, Mack GR, MacDonald RI, Gunther SF, Wilson JN. Kienböck’s disease: the role of silicone replacement arthroplasty. J Bone Joint Surg Am. 1977;59(7):899e908. 3. Watson HK, Ballet FL. The SLAC wrist: scapholunate advanced collapse pattern of degenerative arthritis. J Hand Surg Am. 1984;9(3):358e365.
Letter Regarding “Biomechanical Analysis of Flexor Tendon Repair Using Knotted Kessler and Bunnell Techniques and the Knotless Bunnell Technique” To the Editor: We congratulate the authors on their work and publication in the field of barbed suture repair of
1266
r
Ó 2015 ASSH
r
Published by Elsevier, Inc. All rights reserved.
digital flexor tendons.1 Indeed, hand caregivers continue to debate the ideal flexor tendon surgical technique, suture material, rehabilitation, and other aspects
1267
LETTERS TO THE EDITOR
of this challenging injury. We have also studied the use of barbed suture and found the concept appealing, among other reasons because of the potential for developing a knotless flexor tendon repair that could remove that known weak link in repair technique.2 Using porcine flexor digitorum tendons, the authors of this article compared biomechanical characteristics of 4 repair techniques.1 The first 2 groups served as controls and featured repairs using conventional Kessler and Bunnell sutures. Repairs in the final 2 groups were performed using the Bunnell technique with knotless barbed suture, with and without peripheral suture. Four core strands were used in all groups. The investigators evaluated the performance of each technique in static and dynamic testing. This well-designed study represents a step forward in the field because the authors evaluated the performance of barbed suture in a dynamic model, adding to the results of several prior static and load-to-failure studies. We think performance under dynamic stressing is a key concern for any barbed suture repair technique and may be more important to study for any flexor tendon repair than we previously realized. In current unpublished studies in our biomechanical laboratory, we have performed in situ repairs in zone II in cadaveric hands using bidirectional barbed suture in a manner similar to that described by previous authors. We have a simulated active range of motion apparatus that is able to apply alternating tension on the flexor and extensor tendons to bring the fingers through a full range of motion. We believe that subjecting repaired tendons to angular motion through the pulley system likely better approximates the forces encountered during early rehabilitation. Our current studies using this model are showing that the barbed suture repair technique that we are using fails early and catastrophically during this simulated active range of motion. This is in contrast to what we found during traditional single load-to-failure testing of barbed suture constructs. Our hypothesis is that the active range of motion simulation is causing
J Hand Surg Am.
the barbs to sequentially gain and lose purchase and leads to the gap formation and failure compared with a single tensile load that could allow the barbs to grasp and hold. We think this finding is important and we present it here to make other investigators or surgeons aware, who may want to study this suture technique further or even consider using it clinically. Also, based on what we are seeing with this model in our laboratory, we think it is probably important for all novel flexor tendon repair techniques to be tested cyclically in a manner that more closely represents early postoperative rehabilitation. The investigators in the current study found that their barbed suture technique was able to withstand cyclic loading. This may be because their suture technique is better suited to withstand early active range of motion than the techniques we have been studying in our laboratory, or it may be that their model did not recreate the cyclic forces experienced in vivo. In either case, we advocate continued study of barbed suture and all novel flexor tendon repair techniques in a manner that closely mimics in vivo conditions during postoperative rehabilitation as best as possible before clinical adoption. As the authors noted, their study should serve as a guide to further biomechanical and, eventually, in vivo studies. Frederick P. O’Brien III, MD Brent G. Parks, MSc Kenneth R. Means, Jr, MD Curtis National Hand Center MedStar Union Memorial Hospital Baltimore, MD http://dx.doi.org/10.1016/j.jhsa.2015.02.034 REFERENCES 1. Jordan MC, Schmidt K, Meffert RH, Hoelscher-Doht S. Biomechanical analysis of flexor tendon repair using knotted Kessler and Bunnell techniques and the knotless Bunnell technique. J Hand Surg Am. 2015;40(1):115e120. 2. Parikh PM, Davison SP, Higgins JP. Barbed suture tenorrhaphy: an ex vivo biomechanical analysis. Plast Reconstr Surg. 2009;124(5): 1551e1558.
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Vol. 40, June 2015
