Anchored Transosseous-Equivalent Versus Anchorless Transosseous Rotator Cuff Repair: A Biomechanical Analysis in a Cadaveric Model

2017 ◽  
Vol 45 (10) ◽  
pp. 2364-2371 ◽  
Author(s):  
Kelly G. Kilcoyne ◽  
Stanley G. Guillaume ◽  
Catherine V. Hannan ◽  
Evan R. Langdale ◽  
Stephen M. Belkoff ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Rotator Cuff ◽  
Failure Mode ◽  
Failure Load ◽  
Tendon Tear ◽  
Modes Of Failure ◽  
Load To Failure ◽  
Cadaveric Model

Background: The original approach for the repair of torn rotator cuffs involved an open technique with sutures passing through the greater tuberosity and tendon. The development of suture anchors allowed for an all-arthroscopic approach with anchor configurations attempting to re-create a transosseous fixation pattern. Presently, an arthroscopic approach can be combined with a transosseous suture configuration without using anchors. Purpose: To evaluate cyclic loading, ultimate load to failure, and the failure mechanisms of transosseous-equivalent (TOE) repair with anchors and anchorless transosseous (AT) repair of rotator cuff tears. Study Design: Controlled laboratory study. Methods: Supraspinatus tears (25 mm) were created in 20 fresh-frozen, human cadaveric shoulders, which were randomized to TOE or AT repair (10 in each group, paired experimental design). Biomechanical testing was performed with an initial preload, cyclic loading, and load to failure. Optical markers were used to monitor gap formation in 3 planes, and the failure mode was recorded. Paired t tests were used to make comparisons of biomechanical parameters between the groups. Multinomial logistic regression was used to compare failure modes between the groups. Significance was set to .05. Results: The TOE group had a significantly higher mean (±SD) ultimate failure load (578.5 ± 123.8 N) than the AT group (468.7 ± 150.9 N) ( P = .034). The TOE group also had a significantly less mean first-cycle excursion (2.97 ± 1.97 mm) than the AT group (4.70 ± 2.04 mm) ( P = .046). There were no significant differences between the groups in cyclic elongation or linear stiffness during cyclic loading. Primary modes of failure were a type 2 tendon tear with medial tendon disruption in the TOE group (7/10) and a type 1 tendon tear with lateral tendon disruption in the AT group (6/10). Conclusion: TOE repair resulted in a significantly higher mean failure load compared with AT repair in a cadaveric model. The most common modes of failure were a type 2 tendon tear in the TOE group and a type 1 tendon tear in the AT group. Clinical Relevance: A higher mean failure load in TOE versus AT constructs may come at the cost of a less favorable failure mode adjacent to medial anchors at the musculotendinous junction, potentially making revision difficult.

scholarly journals Failed Dermal Allograft Procedures in Irreparable Rotator Cuff Tears Can Still Improve Pain and Function. The “Biologic Tuberoplasty Effect”

2018 ◽  
Vol 6 (7_suppl4) ◽  
pp. 2325967118S0009
Author(s):  
Raffy Mirzayan ◽  
Michael Allan Stone ◽  
Michael Batech ◽  
Daniel Acevedo ◽  
Anshu Singh
Keyword(s):  
Rotator Cuff ◽  
Average Length ◽  
Rotator Cuff Tears ◽  
Double Row ◽  
Significant Difference ◽  
Goutallier Classification ◽  
And Function ◽  
Type 3

Objectives: Massive rotator cuff tears (MRCT) are a challenging problem. Dermal allografts have been used in “bridging” procedures and superior capsule reconstruction (SCR). Both have led to clinical improvement, but without correlation with post-operative imaging. The purpose of this study is to examine graft integrity on MRI in patients who underwent an SCR or bridging procedure to determine if graft integrity correlates with functional outcome. We also propose a new classification of dermal allograft re-tear on MRI. Methods: This study was approved by our IRB. Between 2006 and 2016, 11 patients (12 shoulders) underwent a bridging procedure and 10 patients underwent an SCR for MRCT with a dermal allograft by a single surgeon. The grafts were secured to the tuberosity in a double-row, trans-osseous equivalent (DR-TOE) fashion. Pre- and post-operative VAS, acromiohumeral distance (AHD), and ASES scores, and pre-operative Hamada grade and Goutallier classification were prospectively collected and retrospectively reviewed. An MRI was obtained on all patients post-operatively to assess graft integrity. The status of the graft was divided into three types based on MRI findings: Type 1- Graft intact medially (rim of cuff or glenoid) AND laterally (greater tuberosity); Type 2- Graft intact laterally but torn medially; Type 3- Graft torn laterally. The shoulders were then grouped based on these types for further analysis. Results: The average age was 61 (range: 49-73). Average follow-up was 21.6 months (range: 8-80). Average length from surgery to MRI was 13.9 months (range: 6-80). There was a significant improvement in VAS (pre-8.1 to post-1.3) and ASES (pre-26.3 to post-84.6) in Type 1 (P<0.01) and in VAS (pre-7.0 to post-0.7) and ASES (pre-32.6 to post-91.2) in Type 2 (P<0.01). There was no difference in post-operative VAS (1.3 vs 0.7) and ASES (84.6 vs 91.2) between Type 1 and Type 2 (P=0.8). There was no improvement in VAS (pre-7.3 vs post-5.7) and ASES (pre-30.6 vs post-37.2) in Type 3. There was a significant difference in post-operative VAS (5.7 vs 1) and ASES (37.2 vs 88.1) between Type 3 versus Types 1+2, respectively (P<0.01). The AHD decreased in type 3 (pre-7.8 mm to post-3.2 mm, P=0.02) but did not change in Types 1+2 (pre-7.8 mm to post-8.0 mm, P=0.7). Conclusion: In patients who have SCR or “bridging” procedures for MRCT with a dermal allograft, there is significant improvement in VAS and ASES scores if the graft heals to the tuberosity, regardless if it is still intact to the glenoid (in SCR) or the rim of rotator cuff tendon (“bridging”). Individuals whose graft is torn from the tuberosity did not have improvement in VAS or ASES scores versus baseline. There was no significant difference in AHD in all groups. We believe that the dermal graft acts as a “biologic (interpositional) tuberoplasty,” preventing bone-to-bone contact between the tuberosity and the acromion, thus eliminating pain and improving function. We still recommend performing an SCR when indicated because it has been shown to restore the normal kinematics of the shoulder in a laboratory setting. However, careful attention should be paid to the repair of the graft to the tuberosity, so that in case the primary procedure fails medially, the graft can still improve pain and function.

Arthroscopic Suture Material and Knot Type

2009 ◽  
Vol 37 (8) ◽  
pp. 1578-1585 ◽  
Author(s):  
Kenneth G. Swan ◽  
Todd Baldini ◽  
Eric C. McCarty
Keyword(s):  
Cyclic Loading ◽  
Failure Load ◽  
Suture Material ◽  
Medical Center ◽  
Maximum Load ◽  
Suture Materials ◽  
Failure Characteristics ◽  
Failure Data ◽  
Load To Failure ◽  
Range Test

Background Several new arthroscopic suture materials are available. It is important for surgeons to know which suture-knot combination provides the strongest construct. Hypothesis The newer, polyblend sutures have dissimilar load-to-failure characteristics. Study Design Controlled laboratory study. Methods The load to failure of 4 knots was evaluated (surgeon's, Duncan loop, Samsung Medical Center [SMC], and Roeder) using 5 No. 2 suture materials (Ethibond, Ticron, FiberWire, ForceFiber, MaxBraid). One surgeon tied all knots. Fifteen samples were tested for each suture-knot configuration. Knots were pretensioned to 10 N, then loaded to failure at a rate of 1.0 mm/s. Failure load recorded was the maximum load applied between 0 and 3 mm of displacement. Cyclic loading of suture-knot samples was performed on 3 knots (surgeon's, Duncan loop, and SMC) using 4 suture materials (Ethibond, FiberWire, ForceFiber, MaxBraid). Six samples were tested for each suture-knot configuration. Knots were cyclically loaded from 5 to 40 N at 0.5 Hz for 1000 cycles, then loaded to failure. Data were compared with analysis of variance and the Tukey multiple range test and considered significant at P <. 05. Results The surgeon's and SMC knots were strongest, particularly if tied using MaxBraid or ForceFiber. With single load-to-failure testing, MaxBraid was significantly stronger than Ethibond, Ticron, or FiberWire, regardless of knot type used. ForceFiber was stronger than Ethibond and Ticron with any knot type, and stronger than FiberWire when tied with a surgeon's knot or Roeder knot. The MaxBraid surgeon's knot (246 N) and MaxBraid SMC knot (239 N) were more than twice as strong as the Ethibond surgeon's knot (111 N) and Ethibond SMC (118 N). With cyclic loading, MaxBraid and ForceFiber were stronger than FiberWire and Ethibond, regardless of knot type tied. The SMC knot using MaxBraid withstood the highest load, and was stronger than the Duncan loop tied with MaxBraid. When stricter criteria (1-mm and 2-mm displacement) for failure were used, MaxBraid and ForceFiber remained superior to other sutures, including FiberWire, but knot type became less significant. Conclusion Nonabsorbable polyblend sutures are stronger than traditional sutures, but not all polyblend sutures are alike. MaxBraid and ForceFiber provide a stronger knot than FiberWire, Ethibond, and Ticron, particularly if tied using a surgeon's or SMC knot. Clinical Relevance The SMC knot using MaxBraid provides the strongest knot/suture combination of knots and sutures tested.

scholarly journals Bone Staples Provide Favorable Primary Stability in Cortical Fixation of Tendon Grafts for Medial Collateral Ligament Reconstruction: A Biomechanical Study

2021 ◽  
Vol 9 (7) ◽  
pp. 232596712110178
Author(s):  
Johannes Glasbrenner ◽  
Adrian Deichsel ◽  
Michael J. Raschke ◽  
Thorben Briese ◽  
Andre Frank ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Medial Collateral Ligament ◽  
Ligament Reconstruction ◽  
Failure Load ◽  
Primary Stability ◽  
Tendon Graft ◽  
Materials Testing ◽  
Collateral Ligament ◽  
Load To Failure ◽  
Tendon Grafts

Background: The use of the interference screw (IFS) for the cortical fixation of tendon grafts in knee ligament reconstruction may lead to converging tunnels in the multiligament reconstruction setting. It is unknown whether alternative techniques using modern suture anchor (SA) or bone staple (BS) fixation provide sufficient primary stability. Purpose: To assess the primary stability of cortical fixation of tendon grafts for medial collateral ligament (MCL) reconstruction using modern SA and BS methods in comparison with IFS fixation. Study Design: Controlled laboratory study. Methods: Cortical tendon graft fixation was performed in a porcine knee model at the tibial insertion area of the MCL using 3 different techniques: IFS (n = 10), SA (n = 10), and BS (n = 10). Specimens were mounted in a materials testing machine, and cyclic loading for 1000 cycles at up to 100 N was applied to the tendon graft, followed by load-to-failure testing. Statistical analysis was performed using 1-way analysis of variance. Results: There were no statistical differences in elongation during cyclic loading or peak failure load during load-to-failure testing between BS (mean ± standard deviation: 3.4 ± 1.0 mm and 376 ± 120 N, respectively) and IFS fixation (3.9 ± 1.2 mm and 313 ± 99.5 N, respectively). SA fixation was found to have significantly more elongation during cyclic loading (6.4 ± 0.9 mm; P < .0001) compared with BS and IFS fixation and lower peak failure load during ultimate failure testing (228 ± 49.0 N; P < .01) compared with BS fixation. Conclusion: BS and IFS fixation provided comparable primary stability in the cortical fixation of tendon grafts in MCL reconstruction, whereas a single SA fixation led to increased elongation with physiologic loads. However, load to failure of all 3 fixation techniques exceeded the loads expected to occur in the native MCL. Clinical Relevance: The use of BS as a reliable alternative to IFS fixation for peripheral ligament reconstruction in knee surgery can help to avoid the conflict of converging tunnels.

scholarly journals Proximal Hamstring Repair: A Biomechanical Analysis of Variable Suture Anchor Constructs

2019 ◽  
Vol 7 (2) ◽  
pp. 232596711882414 ◽  
Author(s):  
Michael B. Gerhardt ◽  
Benjamin S. Assenmacher ◽  
Jorge Chahla
Keyword(s):  
Cyclic Loading ◽  
Suture Anchor ◽  
Failure Load ◽  
Ultimate Failure Load ◽  
Maximal Load ◽  
Significant Difference ◽  
Load To Failure ◽  
Ultimate Failure ◽  
Maximal Displacement ◽  
Proximal Hamstring

Background: Despite an abundance of literature regarding construct strength for a myriad of anchors and anchor configurations in the shoulder, there remains a paucity of biomechanical studies detailing the efficacy of these implants for proximal hamstring repair. Purpose: To biomechanically evaluate the ultimate failure load and failure mechanism of knotless and knotted anchor configurations for hamstring repair. Study Design: Controlled laboratory study. Methods: A total of 17 cadaveric specimens divided into 3 groups composed of intact hamstring tendons as well as 2 different anchor configurations (all-knotted and all-knotless) underwent first cyclic loading and subsequent maximal loading to failure. This protocol entailed a 10-N preload, followed by 100 cycles incrementally applied from 20 to 200 N at a frequency of 0.5 Hz, and ultimately followed by a load to failure with a loading rate of 33 mm/s. The ultimate failure load and mechanism of failure were recorded for each specimen, as was the maximal displacement of each bone-tendon interface subsequent to maximal loading. Analysis of variance was employed to calculate differences in the maximal load to failure as well as the maximal displacement between the 3 study groups. Holm-Sidak post hoc analysis was applied when necessary. Results: The all-knotless suture anchor construct failed at the highest maximal load of the 3 groups (767.18 ± 93.50 N), including that for the intact tendon group (750.58 ± 172.22 N). There was no statistically significant difference between the all-knotless and intact tendon groups; however, there was a statistically significant difference in load to failure when the all-knotless construct was compared with the all-knotted technique (549.56 ± 20.74 N) ( P = .024). The most common mode of failure in both repair groups was at the suture-tendon interface, whereas the intact tendon group most frequently failed via avulsion of the tendon from its insertion site. Conclusion: Under biomechanical laboratory testing conditions, proximal hamstring repair using all-knotless suture anchors outperformed the all-knotted suture anchor configuration with regard to elongation during cyclic loading and maximal load to failure. Failure in the all-knotted repair group was at the suture-tendon interface in most cases, whereas the all-knotless construct failed most frequently at the musculotendinous junction. Clinical Relevance: No biomechanical studies have clearly identified the optimal anchor configuration to avert proximal hamstring repair failure. Delineating this ideal suture anchor construct and its strength compared with an intact hamstring tendon may alter the current standards for postoperative rehabilitation, which remain extremely conservative and onerous for these patients.

scholarly journals Supraspinatus and deltoid muscle fiber diversity in rotator cuff tear conditions

2019 ◽  
Author(s):  
Morten Kjaer Ravn ◽  
Trine Ivarsen Ostergaard ◽  
Henrik Daa Schroeder ◽  
Jens Randel Nyengaard ◽  
Kate Lykke Lambertsen ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Muscle Fiber ◽  
Muscle Fibers ◽  
Deltoid Muscle ◽  
Cell Types ◽  
Fiber Types ◽  
Musculotendinous Junction ◽  
Fiber Atrophy

Abstract Background: Rotator cuff (RC) tears are associated with RC muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize muscle fiber composition in the supraspinatus (SS) muscle under tear conditions. Methods: Muscle biopsies were obtained from 21 patients undergoing surgery for RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS muscle and control biopsies were harvested from the deltoid muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 muscle fibers/mm 2 and fiber diameter was used to estimate muscle fiber atrophy and hypertrophy. Results: We found significantly more type 2 cells/mm 2 in the SS compared to the DT (p<0.01). In addition, we found a significantly higher fraction of type 1 fibers than type 2 fibers in the DT (p<0.01), whereas both fiber types were equally present in the SS. The diameters of SS cells were generally smaller than those of DT cells. Atrophy of especially SS type 2 fibers was also demonstrated. Fiber atrophy was more pronounced in men than women. Discussion: The changes in the composition of SS muscle cell types suggest a shift from type 1 to type 2 muscle fibers and atrophy of both type 1 and 2 fibers. This composition indicates loss of endurance and rapid fatigue of the SS muscle under RC tear conditions.

scholarly journals Biomechanical Properties of Double-Row Transosseous Rotator Cuff Repair Combined With the Cinch Stitch in the Lateral Row

2021 ◽  
Vol 9 (5) ◽  
pp. 232596712110060
Author(s):  
Kentaro Ito ◽  
Katsunobu Sakaguchi ◽  
Hirosi Sekihata ◽  
Naoki Sugita ◽  
Yuho Kadono
Keyword(s):  
Cyclic Loading ◽  
Rotator Cuff ◽  
Mechanical Strength ◽  
Rotator Cuff Repair ◽  
Biomechanical Properties ◽  
The Self ◽  
Yield Load ◽  
Load To Failure ◽  
Transosseous Repair ◽  
Cuff Repair

Background: The self-cinching stitch has been verified to have high mechanical strength. The mechanical strength of combining transosseous rotator cuff repair (RCR) and the self-cinching stitch in the lateral row is unknown. Purpose/Hypothesis: The purpose of this study was to evaluate the biomechanical properties of transosseous RCR combined with the cinch stitch in the lateral row. We hypothesized that this construct would have better mechanical strength than would transosseous repair using a vertical cinch stitch or simple stitch. Study Design: Controlled laboratory study. Methods: Rotator cuff tears were simulated in 48 porcine shoulder specimens. The tears were repaired using 1 of 6 repair configurations: 2–simple stitch transosseous repair alone (group 2TO), with a vertical cinch stitch (group 2TO-VC), or with a horizontal cinch stitch (group 2TO-HC) or 4–simple stitch transosseous repair alone (group 4TO), with a vertical cinch stitch (group 4TO-VC), or with a horizontal cinch stitch (group 4TO-HC). All specimens were set at a 45° angle from the footprint and underwent cyclic loading from 10 to 160 N for 200 cycles, followed by a load-to-failure test at 10 mm/min. Results: During cyclic loading, all specimens in group 2TO and half of the specimens in group 2TO-VC failed by suture pullout. In the other groups, none of the specimens failed before 200 cycles. The yield load in group 2TO-HC was significantly greater than that in group 2TO-VC (261.43 vs 219.54 N, respectively; P < .05). There were significant differences between groups 4TO-HC and 4TO with regard to elongation (3.92 vs 5.68 mm, respectively), yield load (304.04 vs 246.94 N, respectively), and linear stiffness (63.44 vs 52.28 N/mm, respectively) ( P < .01 for all). Group 4TO-HC also had shorter elongation and a superior yield load and linear stiffness compared with group 2TO-HC ( P < .05 for all), and group 4TO-VC had shorter elongation and a stronger maximum load to failure and yield load than did group 2TO-VC ( P < .05 for all). Conclusion: Increasing the number of medial simple stitches can prevent suture pullout. Adding the horizontal cinch stitch to the lateral row in transosseous repair can further improve biomechanical properties through a self-cinching mechanism. Clinical Relevance: Transosseous RCR with a horizontal cinch stitch in the lateral row may reduce the retear rate.

Proximal and Distal Failure Site Analysis in Percutaneous Achilles Tendon Rupture Repair

2019 ◽  
Vol 40 (12) ◽  
pp. 1424-1429 ◽  
Author(s):  
Pablo Wagner ◽  
Emilio Wagner ◽  
Mario López ◽  
Gastón Etchevers ◽  
Oscar Valencia ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Achilles Tendon ◽  
Tendon Rupture ◽  
Failure Load ◽  
Achilles Tendon Rupture ◽  
Tendon Repair ◽  
Cyclic Testing ◽  
Load To Failure ◽  
Fresh Frozen ◽  
Distal Fixation

Background: Different techniques have been described for percutaneous Achilles tendon rupture repair, but no biomechanical evaluation has been performed separately for proximal and distal suturing techniques. The purpose of this study was to biomechanically analyze proximal versus distal percutaneous Achilles suture configurations during cyclic loading and load to failure. Methods: A simulated, midsubstance rupture was created 6 cm proximal to the calcaneal insertion in fresh-frozen cadaveric Achilles tendons. Fifteen proximal specimens were divided into 3 groups: (A1) triple locking technique, (A2) Bunnell-type technique, and (A3) double Bunnell-type technique. Twelve distal specimens were divided into 2 groups: (B1) triple nonlocking technique and (B2) oblique technique. Repairs were subjected to cyclic testing and load to failure. Load to failure, cause of failure, and tendon elongation were evaluated. Results: None of the proximal specimens and 7/12 of the distal ones failed in cyclic testing. The proximal fixation groups demonstrated significantly more strength than the distal groups ( P = .001), achieving up to 710 N of failure load in Group A3. Groups B1and B2 failed on average at 380 N with no difference between them ( P > .05). The majority of all repairs failed in the suture-tendon interface. Distal groups had more elongation during cyclic testing (13.7 mm) than proximal groups (9.4 mm) ( P = .02). Conclusion: The distal fixation site in this Achilles tendon repair was significantly weaker than the proximal fixation site. A proximal modified suture configuration increased resistance to cyclic loading and load to failure significantly. Clinical Relevance: A modification can be suggested to improve strength of the Achilles repair.

Biomechanical Evaluation of Suture Anchor versus Transosseous Tunnel Patellar Tendon Repair Techniques

2018 ◽  
Vol 32 (08) ◽  
pp. 825-832 ◽  
Author(s):  
Seth L. Sherman ◽  
Brandee Black ◽  
Matthew A. Mooberry ◽  
Katie L. Freeman ◽  
Trevor R. Gulbrandsen ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Failure Mode ◽  
Bone Quality ◽  
Ultimate Load ◽  
Suture Anchor ◽  
Tendon Repair ◽  
Tensile Load ◽  
Significant Difference ◽  
Load To Failure ◽  
Suture Anchor Repair

AbstractThe objective of this study is to compare the cyclic loading strength and ultimate failure load in suture anchor repair versus transosseous tunnel repair of patellar tendons using a cadaver model. Twelve cadaveric patella specimens were used (six matched pairs). Dual-energy X-ray absorptiometry (DXA) measurements were performed to ensure equal bone quality among groups. All right knees were assigned to the suture anchor repair group (n = 6), whereas all left knees were assigned to the transosseous bone tunnel group (n = 6). Suture type and repair configuration were equivalent. After the respective procedures were performed, each patella was mounted into a gripping jig. Tensile load was applied at a rate of 1 Hz between magnitudes of 50 and 150 N, 50 and 200 N, 50 and 250 N, and tensile load at a rate of 0.1 mm/s until failure. Failure was defined as a sharp deviation in the linear load versus displacement curve, and failure mode was recorded. DXA measurements demonstrated equivalence of bone quality between the two groups (p > 0.05). During cyclic load testing, there was only a statistically significant difference between the groups with regard to cyclic loading at the 50 to 200 N loading cycle (p = 0.010). There was no statistically significant difference between the groups with regard to ultimate load to failure (p = 0.43). Failure mode within the suture anchor cohort occurred through anchor pullout except for one, which failed through the tendon. All specimens within the transosseous cohort failed through the midsubstance of the tendon except for one, which failed through suture breakage. Suture anchor repair demonstrated a similar biomechanical profile regarding cyclic loading and ultimate load to failure when compared with “gold standard” transosseous tunnel patellar tendon repair with a trend toward less gapping in the suture anchor group. Using suture anchors for repair of the patella tendon has similar biomechanical properties to transpatellar tunnels but may provide other clinical advantages.

Biomechanical Analysis of Suture Anchor vs Tenodesis Screw for FHL Transfer

2017 ◽  
Vol 38 (7) ◽  
pp. 797-801 ◽  
Author(s):  
Mark C. Drakos ◽  
Michael Gott ◽  
Sydney C. Karnovsky ◽  
Conor I. Murphy ◽  
Bridget A. DeSandis ◽  
...  
Keyword(s):  
Ultimate Load ◽  
Suture Anchor ◽  
Failure Load ◽  
Single Incision ◽  
Screw Fixation ◽  
Inverse Correlation ◽  
Donor Age ◽  
Modes Of Failure ◽  
Load To Failure ◽  
Failure Loads

Background: Chronic Achilles injury is often treated with flexor hallucis longus (FHL) tendon transfer to the calcaneus using 1 or 2 incisions. A single incision avoids the risks of extended dissections yet yields smaller grafts, which may limit fixation options. We investigated the required length of FHL autograft and biomechanical profiles for suture anchor and biotenodesis screw fixation. Methods: Single-incision FHL transfer with suture anchor or biotenodesis screw fixation to the calcaneus was performed on 20 fresh cadaveric specimens. Specimens were cyclically loaded until maximal load to failure. Length of FHL tendon harvest, ultimate load, stiffness, and mode of failure were recorded. Results: Tendon harvest length needed for suture anchor fixation was 16.8 ± 2.1 mm vs 29.6 ± 2.4 mm for biotenodesis screw ( P = .002). Ultimate load to failure was not significantly different between groups. A significant inverse correlation existed between failure load and donor age when all specimens were pooled (ρ = −0.49, P < .05). Screws in younger specimens (fewer than 70) resulted in significantly greater failure loads ( P < .03). No difference in stiffness was found between groups. Modes of failure for screw fixation were either tunnel pullout (n = 6) or tendon rupture (n = 4). Anchor failure occurred mostly by suture breakage (n = 8). Conclusion: Adequate FHL tendon length could be harvested through a single posterior incision for fixation to the calcaneus with either fixation option, but suture anchor required significantly less graft length. Stiffness, fixation strength, and load to failure were comparable between groups. An inverse correlation existed between failure load and donor age. Younger specimens with screw fixation demonstrated significantly greater failure loads. Clinical Relevance: Adequate harvest length for FHL transfer could be achieved with a single posterior incision. There was no difference in strength of fixation between suture anchor and biotenodesis screw.

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