SCIENTIFIC ARTICLE
Biomechanical Analysis of Scapholunate Ligament Repair Techniques Lana Kang, MD,* Eugene T. Ek, MD,* Mike T. Wei, BS,* Kathleen N. Meyers, MS,* Krystle A. Hearns, MA,* Michelle G. Carlson, MD*
Purpose To evaluate the biomechanical properties of 3 scapholunate repair techniques. Methods In 51 cadavers, the scapholunate ligament was exposed through a dorsal approach, incised at its scaphoid insertion, and repaired using 1 of 3 techniques: 2 single-loaded suture anchors, 2 double-loaded suture anchors, or 2 transosseous sutures. Twenty-four repaired specimens underwent load to failure (LTF) testing using tensile distraction on a servo-hydraulic machine. Twenty-seven specimens underwent cyclical testing to measure gap formation at the scapholunate joint. Results The mode of failure was suture pullout through the substance of the ligament in 22 specimens, failure at the bone suture interface in 1, and anchor pullout in 1. Double-loaded anchor repairs demonstrated a significantly higher mean ultimate LTF compared with single-loaded anchor (91 N vs 35 N) and transosseous (91 N vs 60 N) repairs. Transosseous repairs demonstrated a higher mean ultimate LTF compared with single-loaded suture repairs (60 N vs 35 N). After 300 cycles, the average gap for the transosseous repair group was double that for the single- and doubleloaded repairs, although not statistically significant. Conclusions Primary scapholunate ligament repairs using double-loaded suture anchors demonstrated significantly higher strength compared with single-loaded anchors and transosseous repairs. On cyclic loading, transosseous repairs demonstrated the greatest gap formation with no measurable difference between single- and double-loaded repairs. Clinical relevance In a cadaveric model for primary repairs, double-loaded suture anchors demonstrated the highest LTF and offer a similar but unproven performance in vivo. (J Hand Surg Am. 2015;-(-):-e-. Copyright Ó 2015 by the American Society for Surgery of the Hand. All rights reserved.) Key words Scapholunate ligament, repair, SLIL, ligament, wrist.
F
complete tear of the scapholunate ligament is an indication for primary surgical repair.1 The preferred technique is uncertain. Methods of repair include end-to-end ligament repair, suture anchors, and bone tunnels. The OR MANY HAND SURGEONS, AN ACUTE
From the *Division of Hand and Upper Extremity Surgery and the Department of Biomechanics, Hospital for Special Surgery, New York, NY. Received for publication November 11, 2014; accepted in revised form March 26, 2015. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Michelle G. Carlson, MD, Hospital for Special Surgery, 523 East 72nd Street, New York, NY 10021; e-mail: [email protected]. 0363-5023/15/---0001$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2015.03.031
nature of the ligamentous injury (ie, intra-substance vs avulsion tear) is one factor in the choice between suture anchors and bone tunnels.2 Whereas results of specific reconstruction techniques for a spectrum of chronic scapholunate injuries have been reported, there are few published data assessing results for acute primary repair of the ligament. Analogous to the biomechanical studies comparing suture techniques for rotator cuff repairs,3,4 this study assessed the performance of 3 different scapholunate ligament suture techniques for acute repair. The purpose of this study was to determine whether one suture technique was biomechanically superior, and therefore to offer guidance for hand surgeons when choosing among them. We hypothesized that
Ó 2015 ASSH
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Published by Elsevier, Inc. All rights reserved.
r
1
2
SCAPHOLUNATE LIGAMENT REPAIR
FIGURE 1: A After incision of the scapholunate ligament from its scaphoid attachment, the suture anchor drill holes (asterisk) are made in the dorsal and proximal attachment sites of the interosseous ligament. B Corresponding suture anchor drill sites on polyurethane bone models, indicated by green dots. The lunate (L) is on the left and the scaphoid (S) is on the right.
FIGURE 2: Single-loaded suture anchor repair. The lunate (L) is on the left and the scaphoid (S) is on the right. A Two single-loaded suture anchors have been inserted into each drill hole in the scaphoid. B Sutures are placed in the ligament. C Final repair.
anchors (n ¼ 17) using a Mini Mitek anchor with 20 Orthocord (DePuy Orthopaedics, Inc, Warsaw, IN) suture, 2 double-loaded suture anchors (n ¼ 17) using Mini QUICKANCHORS (DePuy Mitek, Raynham, MA) with 2-0 Orthocord suture and 3-0 Ethibond suture (Ethicon, Somerville, NJ), or 2 transosseous sutures (n ¼ 17) with 2-0 Orthocord suture. Measurements within 1 to 2 mm from the articulating surface of the proximal scaphoid to the site of ligament insertion guided suture anchor placement. For the suture anchor repair techniques, 2 holes were created where 2 suture anchors were securely placed along the ligament insertion sites on the scaphoid (Figs. 1e3). For the transosseous technique, similar methods of measurements within 1 to 2 mm off the articulating surface guided systematic location of the entry and exit sites of
an increase in the number of sutures crossing the repair site would increase strength and load to failure and decrease gap formation with cyclic loading. MATERIALS AND METHODS A total of 51 fresh-frozen cadaveric specimens (midforearm to fingertip) were prepared for this study with approval from our institutional review board. A dorsal approach was used to expose the scapholunate joint. For each specimen, inspection of the dorsal, volar, and proximal aspects of the joint confirmed an intact scapholunate ligament. The ligament in its entirety (ie, the dorsal, volar, and intramembranous portions) was sharply dissected off its scaphoid attachment and repaired using 1 of 3 fixation techniques: 2 single-loaded suture J Hand Surg Am.
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FIGURE 3: Double-loaded suture anchor repair. The lunate (L) is on the left and the scaphoid (S) is on the right. A Two double-loaded suture anchors have been inserted into each drill hole in the scaphoid. B Sutures are placed in the ligament. C Final repair.
was saved as a jpeg file. Using ImageJ (National Institutes of Health, http://rsb.info.nih.gov/ij/), the distance between markers was recorded for each cycle of interest in each specimen, to enable consistent gap measurements. Gapping was normalized to the 0 cycle measurement at the 25-N load level. The cyclic load levels were determined during load to failure testing using 3 and 25 N to represent 10% to 80% of ultimate failure load for the weakest failure group. We set 300 cycles as the maximum, determined by pilot-testing that showed that after 300 cycles the gapping reached a plateau. Gap formation was measured on all specimens that completed the 300 cycles. One-way analysis of variance was used to analyze the load to failure data and gap formation data. Alpha was set at .050.
2 bone tunnels. This enabled the passage of two 2-0 Orthocord sutures (Fig. 4). After repair, we excised the scaphoid and lunate as a unit. Both the scaphoid and lunate were potted in a custom jig using an epoxy compound (Bondo body filler, 3M, St Paul, MN) and then placed in custom grips on a servo-hydraulic load frame (MTS, Eden Prairie, MN) (Fig. 5). For all testing, specimens were oriented such that the scaphoid and lunate were placed in their reduced position and the applied force was in line with the coronal plane of the dorsal scapholunate ligament. A total of 24 specimens (3 sets of 8 specimens from each of the repair groups) were tested in tension to failure at a rate of 10 mm/min. Ultimate load to failure was calculated and the mode of failure was noted. The second group of 27 specimens (9 from each of the repair groups) underwent cyclic testing at 1 Hz from 3 to 25 N for 300 cycles. Two markers measured within 1 to 2 mm off the articulating surface were placed into the scaphoid and lunate at the site of ligament insertion (4 markers total). Video recording was set at 30 frames/s during the course of cyclic testing. Visual cue cards were used to mark the cycles of interest (0, 10, 25, 50, 100, 150, 200, and 300 cycles). Once the cycle of interest was found, each frame of the cycle was visually assessed to determine which frame showed the maximum gap defined to correlate with maximum load. The frame from each cycle of interest, in which maximum load was applied, J Hand Surg Am.
RESULTS The mode of failure in 22 specimens was pullout of the sutures through the substance of the scapholunate ligament. In the remaining 2 specimens, one failed at the bone-suture interface (transosseous group) and one had the anchor pull out of the bone (double-loaded group). Repairs using double-loaded suture anchors demonstrated a significantly higher mean ultimate load to failure compared with single-loaded suture anchors and transosseous suture repairs. Transosseous suture repairs demonstrated a higher mean ultimate load to failure compared with single-loaded suture repairs (Fig. 6). r
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FIGURE 4: Transosseous repair. The lunate (L) is on the left and the scaphoid (S) is on the right. A Illustration of transosseous repair. B Sutures are placed in the scapholunate ligament. C The sutures have been passed through the corresponding bone tunnels. D Final repair.
On cyclic loading, 2 specimens from the transosseous group failed before reaching 300 cycles (at 12 and 27 cycles) and were not included in gap formation analysis. The average increase in gap for the remaining transosseous suture repair group at 300 cycles (1.7 mm) was approximately 2 times larger than the average gap for the single- (0.9 mm) and double-loaded repairs (0.8 mm) (Fig. 7). These differences were not statistically significant (P > .050) because of large SDs. DISCUSSION Compared with the number of studies reporting results after scapholunate ligament reconstruction, fewer studies report results after acute scapholunate ligament repair.5e7 This study was designed to provide information on the biomechanical performance of 3 different repair techniques for an acute scapholunate ligamentous tear. Investigation as to whether certain suture techniques exhibited biomechanical advantages over others would offer new data to potentially optimize results after surgery, and motivated this study. J Hand Surg Am.
FIGURE 5: Testing setup with a specimen mounted on the servohydraulic load frame (MTS).
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FIGURE 6: Average load to failure for each repair group. *Comparison of single-loaded and double-loaded anchor repair, P < .001. **Comparison of double-loaded anchor and transosseous repair, P < .050. ***Comparison of single-loaded anchor and transosseous repair, P < .050.
FIGURE 7: Average gap formation for each repair group of the course of cyclic testing.
Lavernia et al8 described surgical repair for acute tears in 1992. Educational reviews have echoed use of this technique demonstrating the legacy of this approach.9,10 Szabo2 offered helpful instruction that choice between suture anchors and bone tunnels may be made depending on the site of ligament avulsion or tear. Although a survey of hand surgeon members of the American and Canadian hand surgery societies indicated J Hand Surg Am.
that most surgeons prefer to acutely repair the scapholunate ligament combined with dorsal capsulodesis, specific repair techniques of the acutely torn ligament were not reported.1 We used a previously reported model.11,12 Most studies focused on testing methods of reconstruction rather than on primary repair. Thus, the results of this study may aid surgeons when choosing among repair r
Vol. -, - 2015
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SCAPHOLUNATE LIGAMENT REPAIR
ACKNOWLEDGMENT This study was supported by an in-kind donation of the Mini QuickAnchor Plus system from DePuy Miket, LLC. This agency had no influence over the study design or conduct, or in the data analysis or interpretation.
techniques for primary repair of the scapholunate interosseous ligament (SLIL). Biomechanical testing between transosseous sutures and suture anchors have been reported for rotator cuff repairs, biceps tendon repairs, and quadriceps repairs with variable findings, and several suggest that transosseous repairs perform slightly superior to or comparable to double-loaded suture anchors.3,4,13e15 Our study found that a transosseous repair was inferior to a double-loaded suture anchor under tensile loading. One reason may be because the scapholunate ligament is short and is not a tendon. This study has several limitations. Because of the small number of specimens, although the average gap during cyclic loading was approximately twice as large for the suture repair group, compared to the single- and double-loaded anchors, this difference was not statistically significant. A second limitation was the isolated testing of a construct, which imposes limited applicability of the findings, given a host of unknown effects on healing potential, scar formation, and effects on ultimate clinical functional parameters. A third limitation is that it remains unknown what combination of altered ligament integrity and external rotational forces result in an isolated acute SLIL tear. These unknowns contribute to the limited capacity of force testing to replicate the postrepair stresses perfectly. However, because some specimens fail, it stands to reason that stronger is better, although none approached the 260-N failure force of the native SLIL found by Berger et al.12 Finally, the large SDs in the gap formation data suggest that more specimens would be needed to show significance. These SDs were largest in the transosseous group, which may point to higher variability in this surgical technique. Relative to these constraints, however, the information offered by the results of this study serves as reference for the direction of future investigation and potentially guides the choice of suture technique when faced clinically with acute, isolated scapholunate injuries.
J Hand Surg Am.
REFERENCES 1. Zarkadas PC, Gropper PT, White NJ, Perey BH. A survey of the surgical management of acute and chronic scapholunate instability. J Hand Surg Am. 2004;29(5):848e857. 2. Szabo RM. Scapholunate ligament repair with capsulodesis reinforcement. J Hand Surg Am. 2008;33(9):1645e1654. 3. Chhabra A, Goradia VK, Francke El, et al. In vitro analysis of rotator cuff repairs: a comparison of arthroscopically inserted tacks or anchors with open transosseous repairs. Arthroscopy. 2005;21:323e327. 4. Wheeler DJ, Garabekyan T, Lugo R, et al. Biomechanical comparison of transosseous versus suture anchor repair of the subscapularis tendon. Arthroscopy. 2010;26(4):444e450. 5. Pilný J, Kubes J, Cizmár I, Visna P. Our experience with repair of the scapholunate ligament using the MITEK bone anchor. Acta Chir Orthop Traumatol Cech. 2005;72(6):381e386. 6. Rosati M, Parchi P, Cacianti M, Poggetti A, Lisanti M. Treatment of acute scapholunate ligament injuries with bone anchor. Musculoskelet Surg. 2010;94(1):25e32. 7. Short WH, Werner FW, Sutton LG. Treatment of scapholunate dissociation with a bioresorbable polymer plate: a biomechanical study. J Hand Surg Am. 2008;33(5):643e649. 8. Lavernia CJ, Cohen MS, Taleisnik J. Treatment of scapholunate dissociation by ligamentous repair and capsulodesis. J Hand Surg Am. 1992;71(2):354e359. 9. Kuo CE, Wolfe SW. Scapholunate instability: current concepts in diagnosis and management. J Hand Surg Am. 2008;33(6):998e1013. 10. Kitay A, Wolfe SW. Scapholunate instability: current concepts in diagnosis and management. J Hand Surg Am. 2012;37(10):2175e2196. 11. Endress R, Woon CYL, Farnebo SJ, et al. Tissue-engineered collateral ligament composite allografts for scapholunate ligament reconstruction: an experimental study. J Hand Surg Am. 2012;37(8):1529e1537. 12. Berger RA, Imeada T, Berglund L, An K. Constraint and material properties of the subregions of scapholunate interosseous ligament. J Hand Surg Am. 1999;24(5):953e962. 13. Hart ND, Wallace MK, Scovell JF, Krupp RJ, Cook C, Wyland DJ. Quadriceps tendon rupture: a biomechanical comparison of transosseous equivalent double-row suture anchor versus transosseous tunnel repair. J Knee Surg. 2012;25(4):335e339. 14. Klein DM, Ghany N, Urban W, Caruso SA. Distal biceps tendon repair; anchor versus transosseous suture fixation. Am J Orthop. 2007;36(1):34e37. 15. Lighthart WA, Cohen DA, Levine RG, Parks BG, Boucher HR. Suture anchor versus suture through tunnel fixation for quadriceps tendon rupture: a biomechanical study. Orthopedics. 2008;31(5):441.
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Biomechanical Analysis of Scapholunate Ligament Repair Techniques Lana Kang, MD,* Eugene T. Ek, MD,* Mike T. Wei, BS,* Kathleen N. Meyers, MS,* Krystle A. Hearns, MA,* Michelle G. Carlson, MD*
Purpose To evaluate the biomechanical properties of 3 scapholunate repair techniques. Methods In 51 cadavers, the scapholunate ligament was exposed through a dorsal approach, incised at its scaphoid insertion, and repaired using 1 of 3 techniques: 2 single-loaded suture anchors, 2 double-loaded suture anchors, or 2 transosseous sutures. Twenty-four repaired specimens underwent load to failure (LTF) testing using tensile distraction on a servo-hydraulic machine. Twenty-seven specimens underwent cyclical testing to measure gap formation at the scapholunate joint. Results The mode of failure was suture pullout through the substance of the ligament in 22 specimens, failure at the bone suture interface in 1, and anchor pullout in 1. Double-loaded anchor repairs demonstrated a significantly higher mean ultimate LTF compared with single-loaded anchor (91 N vs 35 N) and transosseous (91 N vs 60 N) repairs. Transosseous repairs demonstrated a higher mean ultimate LTF compared with single-loaded suture repairs (60 N vs 35 N). After 300 cycles, the average gap for the transosseous repair group was double that for the single- and doubleloaded repairs, although not statistically significant. Conclusions Primary scapholunate ligament repairs using double-loaded suture anchors demonstrated significantly higher strength compared with single-loaded anchors and transosseous repairs. On cyclic loading, transosseous repairs demonstrated the greatest gap formation with no measurable difference between single- and double-loaded repairs. Clinical relevance In a cadaveric model for primary repairs, double-loaded suture anchors demonstrated the highest LTF and offer a similar but unproven performance in vivo. (J Hand Surg Am. 2015;-(-):-e-. Copyright Ó 2015 by the American Society for Surgery of the Hand. All rights reserved.) Key words Scapholunate ligament, repair, SLIL, ligament, wrist.
F
complete tear of the scapholunate ligament is an indication for primary surgical repair.1 The preferred technique is uncertain. Methods of repair include end-to-end ligament repair, suture anchors, and bone tunnels. The OR MANY HAND SURGEONS, AN ACUTE
From the *Division of Hand and Upper Extremity Surgery and the Department of Biomechanics, Hospital for Special Surgery, New York, NY. Received for publication November 11, 2014; accepted in revised form March 26, 2015. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Michelle G. Carlson, MD, Hospital for Special Surgery, 523 East 72nd Street, New York, NY 10021; e-mail: [email protected]. 0363-5023/15/---0001$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2015.03.031
nature of the ligamentous injury (ie, intra-substance vs avulsion tear) is one factor in the choice between suture anchors and bone tunnels.2 Whereas results of specific reconstruction techniques for a spectrum of chronic scapholunate injuries have been reported, there are few published data assessing results for acute primary repair of the ligament. Analogous to the biomechanical studies comparing suture techniques for rotator cuff repairs,3,4 this study assessed the performance of 3 different scapholunate ligament suture techniques for acute repair. The purpose of this study was to determine whether one suture technique was biomechanically superior, and therefore to offer guidance for hand surgeons when choosing among them. We hypothesized that
Ó 2015 ASSH
r
Published by Elsevier, Inc. All rights reserved.
r
1
2
SCAPHOLUNATE LIGAMENT REPAIR
FIGURE 1: A After incision of the scapholunate ligament from its scaphoid attachment, the suture anchor drill holes (asterisk) are made in the dorsal and proximal attachment sites of the interosseous ligament. B Corresponding suture anchor drill sites on polyurethane bone models, indicated by green dots. The lunate (L) is on the left and the scaphoid (S) is on the right.
FIGURE 2: Single-loaded suture anchor repair. The lunate (L) is on the left and the scaphoid (S) is on the right. A Two single-loaded suture anchors have been inserted into each drill hole in the scaphoid. B Sutures are placed in the ligament. C Final repair.
anchors (n ¼ 17) using a Mini Mitek anchor with 20 Orthocord (DePuy Orthopaedics, Inc, Warsaw, IN) suture, 2 double-loaded suture anchors (n ¼ 17) using Mini QUICKANCHORS (DePuy Mitek, Raynham, MA) with 2-0 Orthocord suture and 3-0 Ethibond suture (Ethicon, Somerville, NJ), or 2 transosseous sutures (n ¼ 17) with 2-0 Orthocord suture. Measurements within 1 to 2 mm from the articulating surface of the proximal scaphoid to the site of ligament insertion guided suture anchor placement. For the suture anchor repair techniques, 2 holes were created where 2 suture anchors were securely placed along the ligament insertion sites on the scaphoid (Figs. 1e3). For the transosseous technique, similar methods of measurements within 1 to 2 mm off the articulating surface guided systematic location of the entry and exit sites of
an increase in the number of sutures crossing the repair site would increase strength and load to failure and decrease gap formation with cyclic loading. MATERIALS AND METHODS A total of 51 fresh-frozen cadaveric specimens (midforearm to fingertip) were prepared for this study with approval from our institutional review board. A dorsal approach was used to expose the scapholunate joint. For each specimen, inspection of the dorsal, volar, and proximal aspects of the joint confirmed an intact scapholunate ligament. The ligament in its entirety (ie, the dorsal, volar, and intramembranous portions) was sharply dissected off its scaphoid attachment and repaired using 1 of 3 fixation techniques: 2 single-loaded suture J Hand Surg Am.
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FIGURE 3: Double-loaded suture anchor repair. The lunate (L) is on the left and the scaphoid (S) is on the right. A Two double-loaded suture anchors have been inserted into each drill hole in the scaphoid. B Sutures are placed in the ligament. C Final repair.
was saved as a jpeg file. Using ImageJ (National Institutes of Health, http://rsb.info.nih.gov/ij/), the distance between markers was recorded for each cycle of interest in each specimen, to enable consistent gap measurements. Gapping was normalized to the 0 cycle measurement at the 25-N load level. The cyclic load levels were determined during load to failure testing using 3 and 25 N to represent 10% to 80% of ultimate failure load for the weakest failure group. We set 300 cycles as the maximum, determined by pilot-testing that showed that after 300 cycles the gapping reached a plateau. Gap formation was measured on all specimens that completed the 300 cycles. One-way analysis of variance was used to analyze the load to failure data and gap formation data. Alpha was set at .050.
2 bone tunnels. This enabled the passage of two 2-0 Orthocord sutures (Fig. 4). After repair, we excised the scaphoid and lunate as a unit. Both the scaphoid and lunate were potted in a custom jig using an epoxy compound (Bondo body filler, 3M, St Paul, MN) and then placed in custom grips on a servo-hydraulic load frame (MTS, Eden Prairie, MN) (Fig. 5). For all testing, specimens were oriented such that the scaphoid and lunate were placed in their reduced position and the applied force was in line with the coronal plane of the dorsal scapholunate ligament. A total of 24 specimens (3 sets of 8 specimens from each of the repair groups) were tested in tension to failure at a rate of 10 mm/min. Ultimate load to failure was calculated and the mode of failure was noted. The second group of 27 specimens (9 from each of the repair groups) underwent cyclic testing at 1 Hz from 3 to 25 N for 300 cycles. Two markers measured within 1 to 2 mm off the articulating surface were placed into the scaphoid and lunate at the site of ligament insertion (4 markers total). Video recording was set at 30 frames/s during the course of cyclic testing. Visual cue cards were used to mark the cycles of interest (0, 10, 25, 50, 100, 150, 200, and 300 cycles). Once the cycle of interest was found, each frame of the cycle was visually assessed to determine which frame showed the maximum gap defined to correlate with maximum load. The frame from each cycle of interest, in which maximum load was applied, J Hand Surg Am.
RESULTS The mode of failure in 22 specimens was pullout of the sutures through the substance of the scapholunate ligament. In the remaining 2 specimens, one failed at the bone-suture interface (transosseous group) and one had the anchor pull out of the bone (double-loaded group). Repairs using double-loaded suture anchors demonstrated a significantly higher mean ultimate load to failure compared with single-loaded suture anchors and transosseous suture repairs. Transosseous suture repairs demonstrated a higher mean ultimate load to failure compared with single-loaded suture repairs (Fig. 6). r
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FIGURE 4: Transosseous repair. The lunate (L) is on the left and the scaphoid (S) is on the right. A Illustration of transosseous repair. B Sutures are placed in the scapholunate ligament. C The sutures have been passed through the corresponding bone tunnels. D Final repair.
On cyclic loading, 2 specimens from the transosseous group failed before reaching 300 cycles (at 12 and 27 cycles) and were not included in gap formation analysis. The average increase in gap for the remaining transosseous suture repair group at 300 cycles (1.7 mm) was approximately 2 times larger than the average gap for the single- (0.9 mm) and double-loaded repairs (0.8 mm) (Fig. 7). These differences were not statistically significant (P > .050) because of large SDs. DISCUSSION Compared with the number of studies reporting results after scapholunate ligament reconstruction, fewer studies report results after acute scapholunate ligament repair.5e7 This study was designed to provide information on the biomechanical performance of 3 different repair techniques for an acute scapholunate ligamentous tear. Investigation as to whether certain suture techniques exhibited biomechanical advantages over others would offer new data to potentially optimize results after surgery, and motivated this study. J Hand Surg Am.
FIGURE 5: Testing setup with a specimen mounted on the servohydraulic load frame (MTS).
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FIGURE 6: Average load to failure for each repair group. *Comparison of single-loaded and double-loaded anchor repair, P < .001. **Comparison of double-loaded anchor and transosseous repair, P < .050. ***Comparison of single-loaded anchor and transosseous repair, P < .050.
FIGURE 7: Average gap formation for each repair group of the course of cyclic testing.
Lavernia et al8 described surgical repair for acute tears in 1992. Educational reviews have echoed use of this technique demonstrating the legacy of this approach.9,10 Szabo2 offered helpful instruction that choice between suture anchors and bone tunnels may be made depending on the site of ligament avulsion or tear. Although a survey of hand surgeon members of the American and Canadian hand surgery societies indicated J Hand Surg Am.
that most surgeons prefer to acutely repair the scapholunate ligament combined with dorsal capsulodesis, specific repair techniques of the acutely torn ligament were not reported.1 We used a previously reported model.11,12 Most studies focused on testing methods of reconstruction rather than on primary repair. Thus, the results of this study may aid surgeons when choosing among repair r
Vol. -, - 2015
6
SCAPHOLUNATE LIGAMENT REPAIR
ACKNOWLEDGMENT This study was supported by an in-kind donation of the Mini QuickAnchor Plus system from DePuy Miket, LLC. This agency had no influence over the study design or conduct, or in the data analysis or interpretation.
techniques for primary repair of the scapholunate interosseous ligament (SLIL). Biomechanical testing between transosseous sutures and suture anchors have been reported for rotator cuff repairs, biceps tendon repairs, and quadriceps repairs with variable findings, and several suggest that transosseous repairs perform slightly superior to or comparable to double-loaded suture anchors.3,4,13e15 Our study found that a transosseous repair was inferior to a double-loaded suture anchor under tensile loading. One reason may be because the scapholunate ligament is short and is not a tendon. This study has several limitations. Because of the small number of specimens, although the average gap during cyclic loading was approximately twice as large for the suture repair group, compared to the single- and double-loaded anchors, this difference was not statistically significant. A second limitation was the isolated testing of a construct, which imposes limited applicability of the findings, given a host of unknown effects on healing potential, scar formation, and effects on ultimate clinical functional parameters. A third limitation is that it remains unknown what combination of altered ligament integrity and external rotational forces result in an isolated acute SLIL tear. These unknowns contribute to the limited capacity of force testing to replicate the postrepair stresses perfectly. However, because some specimens fail, it stands to reason that stronger is better, although none approached the 260-N failure force of the native SLIL found by Berger et al.12 Finally, the large SDs in the gap formation data suggest that more specimens would be needed to show significance. These SDs were largest in the transosseous group, which may point to higher variability in this surgical technique. Relative to these constraints, however, the information offered by the results of this study serves as reference for the direction of future investigation and potentially guides the choice of suture technique when faced clinically with acute, isolated scapholunate injuries.
J Hand Surg Am.
REFERENCES 1. Zarkadas PC, Gropper PT, White NJ, Perey BH. A survey of the surgical management of acute and chronic scapholunate instability. J Hand Surg Am. 2004;29(5):848e857. 2. Szabo RM. Scapholunate ligament repair with capsulodesis reinforcement. J Hand Surg Am. 2008;33(9):1645e1654. 3. Chhabra A, Goradia VK, Francke El, et al. In vitro analysis of rotator cuff repairs: a comparison of arthroscopically inserted tacks or anchors with open transosseous repairs. Arthroscopy. 2005;21:323e327. 4. Wheeler DJ, Garabekyan T, Lugo R, et al. Biomechanical comparison of transosseous versus suture anchor repair of the subscapularis tendon. Arthroscopy. 2010;26(4):444e450. 5. Pilný J, Kubes J, Cizmár I, Visna P. Our experience with repair of the scapholunate ligament using the MITEK bone anchor. Acta Chir Orthop Traumatol Cech. 2005;72(6):381e386. 6. Rosati M, Parchi P, Cacianti M, Poggetti A, Lisanti M. Treatment of acute scapholunate ligament injuries with bone anchor. Musculoskelet Surg. 2010;94(1):25e32. 7. Short WH, Werner FW, Sutton LG. Treatment of scapholunate dissociation with a bioresorbable polymer plate: a biomechanical study. J Hand Surg Am. 2008;33(5):643e649. 8. Lavernia CJ, Cohen MS, Taleisnik J. Treatment of scapholunate dissociation by ligamentous repair and capsulodesis. J Hand Surg Am. 1992;71(2):354e359. 9. Kuo CE, Wolfe SW. Scapholunate instability: current concepts in diagnosis and management. J Hand Surg Am. 2008;33(6):998e1013. 10. Kitay A, Wolfe SW. Scapholunate instability: current concepts in diagnosis and management. J Hand Surg Am. 2012;37(10):2175e2196. 11. Endress R, Woon CYL, Farnebo SJ, et al. Tissue-engineered collateral ligament composite allografts for scapholunate ligament reconstruction: an experimental study. J Hand Surg Am. 2012;37(8):1529e1537. 12. Berger RA, Imeada T, Berglund L, An K. Constraint and material properties of the subregions of scapholunate interosseous ligament. J Hand Surg Am. 1999;24(5):953e962. 13. Hart ND, Wallace MK, Scovell JF, Krupp RJ, Cook C, Wyland DJ. Quadriceps tendon rupture: a biomechanical comparison of transosseous equivalent double-row suture anchor versus transosseous tunnel repair. J Knee Surg. 2012;25(4):335e339. 14. Klein DM, Ghany N, Urban W, Caruso SA. Distal biceps tendon repair; anchor versus transosseous suture fixation. Am J Orthop. 2007;36(1):34e37. 15. Lighthart WA, Cohen DA, Levine RG, Parks BG, Boucher HR. Suture anchor versus suture through tunnel fixation for quadriceps tendon rupture: a biomechanical study. Orthopedics. 2008;31(5):441.
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