Biomechanical Evaluation of Classic Solid and All-Soft Suture Anchors for Medial Patellofemoral Ligament Reconstruction

Background: Multiple techniques for patellar fixation with classic solid suture anchors (SAs) in medial patellofemoral ligament (MPFL) reconstruction have been described. Fixation of the graft to the patella with all-soft suture anchors (ASAs) has not been studied. Purpose/Hypothesis: To evaluate the biomechanical performance of 2 different MPFL patellar fixation techniques: ASA fixation and SA fixation. We hypothesized that the ASA group would show no statistical difference in the ultimate failure load and stiffness compared with the SA group. Study Design: Controlled laboratory study. Methods: Reconstruction of the MPFL with gracilis autografts was performed in 16 fresh-frozen cadaveric knees (mean age, 52.6 ± 9.0 years). The specimens were randomly assigned to 2 groups of 8 specimens each based on the method used to fix the graft to the medial patella: ASA or SA fixation. Patellar fixation with ASAs was completed with 2 parallel 1.8-mm anchors (Q-Fix, Smith & Nephew). Fixation with SAs was completed with 2 parallel 2.9-mm anchors (Osteoraptor, Smith & Nephew). The reconstructions were cyclically loaded for 10 cycles to 25 N and then loaded in tension at 6 mm/s until failure. Ultimate failure load (N), displacement (mm), stiffness (N/mm), and mode of failure were recorded for each specimen. Results: Load to failure testing showed an ultimate failure load of 228.5 ± 53.1 N in the ASA group. In the SA group, the ultimate failure load was 156.2 ± 84.9 N. The difference between the 2 groups was not statistically significant ( P = .064). Stiffness values between the ASA and SA groups were not significantly different (21.3 ± 4.1 N/mm vs 20.9 ± 9.3 N/mm, respectively, P = .905). The most common mode of failure in both groups was anchor pullout (8 of 8 in the ASA group; 6 of 8 in the SA group). Conclusion: This experimental study showed no statistically significant differences in biomechanical performance between 1.8-mm ASAs and 2.9-mm SAs. Clinical Relevance: Patellar fixation with 2 parallel ASAs may provide adequate patellar fixation for MPFL reconstruction, while their smaller diameter could potentially decrease the risks for patella fracture and violation of the articular surface in the cadaver model.

Download Full-text

Biomechanical evaluation of a novel double rip-stop technique with medial row knots for rotator cuff repair

Bone and Joint Research ◽

10.1302/2046-3758.96.bjr-2019-0196.r1 ◽

2020 ◽

Vol 9 (6) ◽

pp. 285-292

Author(s):

Zhanwen Wang ◽

Hong Li ◽

Zeling Long ◽

Subin Lin ◽

Andrew R. Thoreson ◽

...

Keyword(s):

Rotator Cuff ◽

Rotator Cuff Repair ◽

Failure Modes ◽

Failure Load ◽

Biomechanical Properties ◽

Gap Formation ◽

Ultimate Failure Load ◽

Fresh Frozen ◽

Ultimate Failure ◽

Cuff Repair

Aims Many biomechanical studies have shown that the weakest biomechanical point of a rotator cuff repair is the suture-tendon interface at the medial row. We developed a novel double rip-stop (DRS) technique to enhance the strength at the medial row for rotator cuff repair. The objective of this study was to evaluate the biomechanical properties of the DRS technique with the conventional suture-bridge (SB) technique and to evaluate the biomechanical performance of the DRS technique with medial row knots. Methods A total of 24 fresh-frozen porcine shoulders were used. The infraspinatus tendons were sharply dissected and randomly repaired by one of three techniques: SB repair (SB group), DRS repair (DRS group), and DRS with medial row knots repair (DRSK group). Specimens were tested to failure. In addition, 3 mm gap formation was measured and ultimate failure load, stiffness, and failure modes were recorded. Results The mean load to create a 3 mm gap formation in the DRSK and DRS groups was significantly higher than in the SB group. The DRSK group had the highest load to failure with a mean ultimate failure load of 395.0 N (SD 56.8) compared to the SB and DRS groups, which recorded 147.1 N (SD 34.3) and 285.9 N (SD 89.8), respectively (p < 0.001 for both). The DRS group showed a significantly higher mean failure load than the SB group (p = 0.006). Both the DRS and DRSK groups showed significantly higher mean stiffness than the SB group. Conclusion The biomechanical properties of the DRS technique were significantly improved compared to the SB technique. The DRS technique with medial row knots showed superior biomechanical performance than the DRS technique alone.

Download Full-text

All Soft-suture Anchor versus Suture Bridge Construct for Insertional Achilles

Foot & Ankle Orthopaedics ◽

10.1177/2473011418s00065 ◽

2018 ◽

Vol 3 (3) ◽

pp. 2473011418S0006

Author(s):

Kenneth Hunt ◽

Pam Kumparatana ◽

Sophia Anderson ◽

Todd Baldini ◽

Daniel Moon ◽

...

Keyword(s):

Failure Load ◽

Lateral Displacement ◽

Clinical Failure ◽

Suture Anchors ◽

Suture Bridge ◽

Ultimate Failure Load ◽

Failure Loads ◽

Tendon Thickness ◽

Ultimate Failure ◽

Group 2

Category: Ankle Introduction/Purpose: New techniques and anchors have been developed for the surgical treatment of insertional Achilles tendinopathy and rupture to allow for earlier return to postoperative weight bearing and accelerated rehabilitation. Two recently introduced soft tissue-to-bone anchor technology have purported advantages for insertional Achilles repairs. Knotless suture anchors allow suture tension to be precisely controlled with a ratcheting mechanism. The other is a suture bridge construct fastened with biotenodesis screws, increasing the soft tissue footprint and reducing the risk of suture pullout through the tendon. However, neither technology has been studied in a biomechanical model of Achilles tendon repair. We hypothesized that there would be no difference in the biomechanical characteristics of a single-row all-suture anchor repair to a double-row repair with knotless anchors and suture tape. Methods: Six matched-pairs of fresh-frozen lower leg cadaveric specimens (12 total) were obtained. All tendons were completely detached from their calcaneal insertions and tendon thickness was measured. Calcaneal exostectomies were performed (e.g., Haglunds removal) above the Achilles insertion. Group 1 was repaired with a single-row construct with two all-soft anchors. Group 2 was repaired with a double-row suture bridge construct with two knotless anchors distally and two suture tape anchors proximally. The repaired specimens were cyclically loaded from 10N to 100N at 1 Hz for 2,000 cycles then to failure at 1mm/sec. A motion capture system measured Achilles-calcaneal displacement at the medial and lateral anchors. Paired t-tests and linear mixed models (LMMs) were used to analyze the following outcomes: clinical failure load, ultimate failure load, Achilles-calcaneal medial and lateral displacement, distance at ultimate failure load, tendon thickness, footprint, and mode of failure. A p-value of <0.05 was considered statistically significant. Results: Group 2 showed significantly less Achilles-calcaneal overall medial and lateral displacement, 19.5% and 36.9% respectively (Table 1). Group 2 showed a statistical trend toward greater clinical and ultimate failure load, 23.8% and 34.2%, respectively (Table1). LMM analyses showed that a suture bridge repair over all-soft anchor repair was independently associated with a 50.24N increase in the load to clinical failure (p=0.0011). Higher clinical failure loads were associated with higher BMI (p<0.0001), thinner tendons (p<0.0001), and smaller tendon footprints on the calcaneus (p=0.0013). Higher absolute failure loads were associated with older age (p<0.0001), higher BMI (p<0.0001), thinner tendons (p=0.0028), and larger footprints (p<0.0001). Conclusion: These data suggest a trend toward higher clinical and ultimate failure loads in a suture bridge construct compared to all-soft suture anchors for insertional Achilles repair. Loads to failure in both groups were higher than previously reported pull-out strengths for most suture anchors (150-300 N), but are lower than typical loads at the Achilles insertion during walking activities. The use of the suture bridge repair method may result in superior loads to failure compared to all-soft anchors. Patient age, BMI and tendon thickness impact failure loads. Adequate healing should be allowed followed repair of complete Achilles detachment.

Download Full-text

Interference Screw Versus Suture Anchors for Femoral Fixation in Medial Patellofemoral Ligament Reconstruction: A Biomechanical Study

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967121989282 ◽

2021 ◽

Vol 9 (3) ◽

pp. 232596712198928

Author(s):

Heath P. Gould ◽

Nicholas R. Delaney ◽

Brent G. Parks ◽

Roshan T. Melvani ◽

Richard Y. Hinton

Keyword(s):

Medial Patellofemoral Ligament ◽

Interference Screw ◽

Biomechanical Study ◽

Graft Fixation ◽

Mpfl Reconstruction ◽

Suture Anchors ◽

Femoral Fixation ◽

Significant Difference ◽

Load To Failure ◽

The Mean

Background: Femoral-sided graft fixation in medial patellofemoral ligament (MPFL) reconstruction is commonly performed using an interference screw (IS). However, the IS method is associated with several clinical disadvantages that may be ameliorated by the use of suture anchors (SAs) for femoral fixation. Purpose: To compare the load to failure and stiffness of SAs versus an IS for the femoral fixation of a semitendinosus autograft in MPFL reconstruction. Study Design: Controlled laboratory study. Methods: Based on a priori power analysis, a total of 6 matched pairs of cadaveric knees were included. Specimens in each pair were randomly assigned to receive either SA or IS fixation. After an appropriate reconstruction procedure, the looped end of the MPFL graft was pulled laterally at a rate of 6 mm/s until construct failure. The best-fit slope of the load-displacement curve was then used to calculate the stiffness (N/mm) in a post hoc fashion. A paired t test was used to compare the mean load to failure and the mean stiffness between groups. Results: No significant difference in load to failure was observed between the IS and the SA fixation groups (294.0 ± 61.1 vs 250.0 ± 55.9; P = .352), although the mean stiffness was significantly higher in IS specimens (34.5 ± 9.6 vs 14.7 ± 1.2; P = .004). All IS reconstructions failed by graft pullout from the femoral tunnel, whereas 5 of the 6 SA reconstructions failed by anchor pullout. Conclusion: In this biomechanical study using a cadaveric model of MPFL reconstruction, SA femoral fixation was not significantly different from IS fixation in terms of load to failure. The mean load-to-failure values for both reconstruction techniques were greater than the literature-reported values for the native MPFL. Clinical Relevance: These results suggest that SAs are a biomechanically viable alternative for femoral-sided graft fixation in MPFL reconstruction.

Download Full-text

Ability of Medial Patellofemoral Ligament Reconstruction to Overcome Lateral Patellar Motion in the Presence of Trochlear Flattening: A Cadaveric Biomechanical Study

The American Journal of Sports Medicine ◽

10.1177/03635465211041087 ◽

2021 ◽

pp. 036354652110410

Author(s):

Amrit V. Vinod ◽

Alex M. Hollenberg ◽

Melissa A. Kluczynski ◽

John M. Marzo

Keyword(s):

Repeated Measures ◽

Knee Flexion ◽

Medial Patellofemoral Ligament ◽

Operative Procedure ◽

Biomechanical Study ◽

Mpfl Reconstruction ◽

Trochlear Groove ◽

Sulcus Angle ◽

Fresh Frozen ◽

Patellar Stability

Background: Medial patellofemoral ligament (MPFL) reconstruction is an established operative procedure to restore medial restraining force in patients with patellar instability. In the setting of a shallow sulcus, it is unclear whether an isolated MPFL reconstruction is sufficient to restore patellofemoral stability. Hypothesis: Progressively increasing the sulcus angle would have an adverse effect on the ability of an MPFL reconstruction to restrain lateral patellar motion. Study Design: Controlled laboratory study. Methods: Seven fresh-frozen human cadaveric knees were harvested and prepared for experimentation. Each specimen was run through the following test conditions: native, lateral retinacular release, lateral retinacular repair, MPFL release, MPFL reconstruction, and MPFL reconstruction with trochlear flattening. Four 3-dimensional printed wedges (10°, 20°, 30°, and 40°) were created to insert beneath the native trochlea to raise the sulcus angle incrementally and simulate progressive trochlear flattening. For each test condition, the knee was positioned at 0°, 15°, 30°, and 45° of flexion, and the force required to displace the patella 1 cm laterally at 10 mm/s was measured. Group comparisons were made with repeated measures analysis of variance. Results: In the setting of an MPFL reconstruction, as the trochlear groove was incrementally flattened, the force required to laterally displace the patella progressively decreased. A 10° increase in the sulcus angle significantly reduced the force at 15° ( P = .01) and 30° ( P = .03) of knee flexion. The force required to laterally displace the patella was also significantly lower at all knee flexion angles after the addition of the 20°, 30°, and 40° wedges ( P≤ .05). Specifically, a 20° increase in the sulcus angle reduced the force by 29% to 36%; a 30° increase, by 35% to 43%; and a 40° increase, by 40% to 47%. Conclusion: Despite an MPFL reconstruction, the force required to laterally displace the patella decreased as the sulcus angle was increased in our cadaveric model. Clinical Relevance: An isolated MPFL reconstruction may not be sufficient to restore patellar stability in the setting of a shallow or flat trochlea. Patients with an abnormal sulcus angle may have recurrent instability postoperatively if treated with an isolated MPFL reconstruction.

Download Full-text

Different Suture Materials for Arthroscopic Transtibial Pull-out Repair of Medial Meniscal Posterior Root Tears: A Human Biomechanical Study

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119873274 ◽

2019 ◽

Vol 7 (9) ◽

pp. 232596711987327

Author(s):

Gilberto Y. Nakama ◽

Zachary S. Aman ◽

Hunter W. Storaci ◽

Alexander S. Kuczmarski ◽

Joseph J. Krob ◽

...

Keyword(s):

Medial Meniscus ◽

Failure Load ◽

Clinical Care ◽

Posterior Root ◽

Clinical Failure ◽

Postoperative Rehabilitation ◽

Pull Out ◽

Ultimate Failure Load ◽

Ultimate Failure ◽

Suture Tape

Background: Transtibial pull-out repair of the medial meniscal posterior root (MMPR) has been largely assessed through biomechanical studies. Biomechanically comparing different suture types would further optimize MMPR fixation and affect clinical care. Purpose/Hypothesis: The purpose of this study was to determine the optimal suture material for MMPR fixation. It was hypothesized that ultra high–molecular weight polyethylene (UHMWPE) suture tape would be biomechanically superior to UHMWPE suture and standard suture. Study Design: Controlled laboratory study. Methods: The MMPR attachment was divided in 24 human cadaveric knees and randomly assigned to 3 repair groups: UHMWPE suture tape, UHMWPE suture, and standard suture. Specimens were dissected down to the medial meniscus, and the posterior root attachments were sectioned off the tibia. Two-tunnel transtibial pull-out repair with 2 sutures, as determined by the testing group, was performed. The repair constructs were cyclically loaded between 10 and 30 N at 0.5 Hz for 1000 cycles to mimic the forces experienced on the medial meniscus during postoperative rehabilitation. Displacement was recorded at 1, 50, 100, 500, and 1000 cycles. Ultimate failure load, displacement at failure, and load at 3 mm of displacement (clinical failure) were also recorded. Results: UHMWPE suture tape had significantly less displacement of the medial meniscus when compared with standard suture at 1 (–0.22 mm [95% CI, –0.41 to –0.02]; P = .025) and 50 (–0.35 mm [95% CI, –0.67 to –0.03]; P = .029) cycles. There were no other significant differences observed in displacement between groups at any number of cycles. UHMWPE suture tape had significantly less displacement at the time of failure than standard suture (–3.71 mm [95% CI, –7.17 to –0.24]; P = .034). UHMWPE suture tape had a significantly higher load to reach the clinical failure displacement of 3 mm than UHMWPE suture (15.64 N [95% CI, 0.02 to 31.26]; P = .05). There were no significant differences in ultimate failure load between groups. Conclusion: The meniscal root repair construct with UHMWPE suture tape may be stronger and less prone to displacement than that with standard suture or UHMWPE suture. Clinical Relevance: UHMWPE suture tape may provide better clinical results compared with UHMWPE suture and standard suture.

Download Full-text

Prestressed concrete masonry walls subjected to uniform out-of-plane loading

Canadian Journal of Civil Engineering ◽

10.1139/l93-128 ◽

1993 ◽

Vol 20 (6) ◽

pp. 969-979

Author(s):

J. L. Dawe ◽

G. G. Aridru

Keyword(s):

Prestressed Concrete ◽

Failure Load ◽

Masonry Walls ◽

Prestressing Force ◽

Concrete Masonry ◽

Ultimate Failure Load ◽

Wall Stiffness ◽

Out Of Plane ◽

Ultimate Failure ◽

Concrete Masonry Walls

Two series of post-tensioned concrete masonry walls subjected to uniform lateral loading were tested to investigate their flexural strength behaviour. Each series of walls consisted of four full-scale prestressed specimens, with varying levels of prestressing force, and one reinforced specimen. Of particular interest were the load–deflection curves, initial cracking loads, wall stiffness, crack patterns, and ultimate failure loads. An air bag test apparatus was used for applying lateral uniform pressures to the specimens. Results of this experimental investigation showed that, for a given wall thickness, increased prestressing force increases the cracking load, initial wall stiffness, and ultimate failure load. The results have established a linear relationship between increased prestressing force and initial cracking load, initial wall stiffness, and ultimate failure load. The proposed model, which takes into account changes in wall stiffness after initial cracking of the wall, accurately predicts wall behaviour. Key words: masonry, prestressed, walls, strength, behaviour, uniform, pressure, experimental, analytical.

Download Full-text

Efficacy of Bone Marrow-Stimulating Technique in Rotator Cuff Repair

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967117s00080 ◽

2017 ◽

Vol 5 (2_suppl2) ◽

pp. 2325967117S0008

Author(s):

İsmail Kerem Bilsel ◽

Fatih Yıldız ◽

Mehmet Kapıcıoglu ◽

Gokcer Uzer ◽

Mehmet Elmadag ◽

...

Keyword(s):

Bone Marrow ◽

Rotator Cuff ◽

Failure Load ◽

Tendon Healing ◽

Histological Evaluation ◽

Control Group ◽

Time Interval ◽

Lesser Tuberosity ◽

Ultimate Failure Load ◽

Ultimate Failure

Background: This study investigates the effect of microfracture as a bone marrow-stimulating(BMS) technique on rotatory cuff(RC) healing using a chronic RC tear model. Methods: Chronic retracted RC tendon tear model was created in the subscapularis(SSC) tendons of 20 New Zealand rabbits, bilaterally. The tendons were repaired after eight weeks using a single-row configuration with suture anchors. In right shoulders, tendons were repaired in a standard fashion(control group). In left shoulders, microfractures were performed on the SSC footprint before repair(microfracture group). The animals were sacrificed 8 and 16 weeks after repair. The repaired tendons were tested biomechanically for their ultimate failure load, linear stiffness and elongation at failure. Gross and histological evaluation of the tendon-to-bone healing was evaluated. Results: In every sample, the SSC tendon was attached to its footprint on the lesser tuberosity. In microfracture group, collagen fibers were organized in relatively ticker bundles at both time intervals. The mean ultimate failure load of microfracture was significantly greater than that of control group at 8 (148.4+31 N vs. 101.4+26 N; p=0.011) and 16 (155+30 N vs. 114.9+25 N; p=0.017) weeks after repair, respectively. There were no significant differences between the two groups at each time interval for linear stiffness (15.9+2.7N/mm vs. 15.8+1.3N/mm, p=0.798 and 16.9+4.3N/mm vs. 17.1+3.6N/mm, p=0.848, respectively) and elongation at failure (4.7+1.1 mm vs. 4.7+1.3 mm, p=0.848 and 4.8+1.5 mm vs. 4.9+0.9 mm, p=0.749, respectively). Conclusions: The BMS technique of microfracture on the tuberosity of the repaired chronic rotator cuff tear promotes the dynamic tendon healing with significant ultimate force to failure and apparent microscopic findings.

Download Full-text

In Vitro Testing of 2 Adjustable-Loop Cortical Suspensory Fixation Systems Versus Interference Screw for Anterior Cruciate Ligament Reconstruction

Orthopaedic Journal of Sports Medicine ◽

10.1177/23259671211031652 ◽

2021 ◽

Vol 9 (9) ◽

pp. 232596712110316

Author(s):

Gerardo L. Garcés ◽

Oscar Martel ◽

Alejandro Yánez ◽

Ignacio Manchado-Herrera ◽

Luci M. Motta

Keyword(s):

Anterior Cruciate Ligament ◽

Acl Reconstruction ◽

Failure Load ◽

Cruciate Ligament ◽

Interference Screw ◽

Yield Load ◽

Ultimate Failure Load ◽

Significant Difference ◽

Ultimate Failure ◽

Anterior Cruciate

Background: It is not clear whether the mechanical strength of adjustable-loop suspension devices (ALDs) in anterior cruciate ligament (ACL) reconstruction is device dependent and if these constructs are different from those of an interference screw. Purpose: To compare the biomechanical differences of 2 types of ALDs versus an interference screw. Study Design: Controlled laboratory study. Methods: ACL reconstruction was performed on porcine femurs and bovine extensor tendons with 3 types of fixation devices: interference screw, UltraButton (UB) ALD, and TightRope (TR) ALD (n = 10 for each). In addition to specimen testing, isolated testing of the 2 ALDs was performed. The loading protocol consisted of 3 stages: preload (static 150 N load for 5 minutes), cyclic load (50-250 N at 1 Hz for 1000 cycles), and load to failure (crosshead speed 50 mm/min). Displacement at different cycles, ultimate failure load, yield load, stiffness, and failure mode were recorded. Results: In specimen testing, displacement of the ALDs at the 1000th cycle was similar (3.42 ± 1.34 mm for TR and 3.39 ± 0.92 mm for UB), but both were significantly lower than that of the interference screw (7.54 ± 3.18 mm) ( P < .001 for both). The yield load of the UB (547 ± 173 N) was higher than that of the TR (420 ± 72 N) ( P = .033) or the interference screw (386 ± 51 N; P = .013), with no significant difference between the latter 2. In isolated device testing, the ultimate failure load of the TR (862 ± 64 N) was significantly lower than that of the UB (1879 ± 126 N) ( P < .001). Conclusion: Both ALDs showed significantly less displacement in cyclic loading at ultimate failure than the interference screw. The yield load of the UB was significantly higher than that of the other 2. The ultimate failure occurred at a significantly higher load for UB than it did for TR in isolated device testing. Clinical Relevance: Both UB and TR provided stronger fixation than an interference screw. Although difficult to assess, intrinsic differences in the mechanical properties of these ALDs may affect clinical outcomes.

Download Full-text

Fracture damage of integrated composite joint for fuselage structure under tensile loading

Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University ◽

10.1051/jnwpu/20213940739 ◽

2021 ◽

Vol 39 (4) ◽

pp. 739-746

Author(s):

Yong Du ◽

Yu'e Ma ◽

Junwu Liu

Keyword(s):

Failure Load ◽

Failure Process ◽

Tensile Load ◽

Interface Debonding ◽

Load Drop ◽

Complex Load ◽

Damage Initiation ◽

Composite Joint ◽

Ultimate Failure Load ◽

Ultimate Failure

In order to solve the complex load transfer and structural design of the joint structures including skin, longeron and frame in the composite fuselage, the adhesively bonded integrated composite joint was designed. Static tensile test was performed and the strain-load curves and damage modes were obtained. Then the numerical simulation model of integrated composite joint was built. The damage initiation, propagation and failure process of integrated composite joint under tensile load were simulated and analyzed. Results show that: the first load drop and the ultimate failure load of the joint are 120.82 kN and 168.11 kN respectively; the initial damage occurs at the corner bend region of the lower-left corner-shaped preform, and extends across the radius bend region among short flange, long flange and web, and leads to the interface debonding of the upper and lower corner-shaped preform and the delamination of corner-shaped preform and L-shaped preform. Compared with the experimental results, the errors of the first load drop and the ultimate failure load from numerical calculated results are 6.68% and 2.61% respectively, which agree with each other very well.

Download Full-text

A BIOMECHANICAL COMPARISON OF SUTURE ANCHOR VS. INTERFERENCE SCREW TECHNIQUE FOR PATELLAR FIXATION FOR MEDIAL PATELLOFEMORAL LIGAMENT RECONSTRUCTION

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00109 ◽

2019 ◽

Vol 7 (3_suppl) ◽

pp. 2325967119S0010

Author(s):

Dragomi Mijic ◽

Sanar Yokhana ◽

Kunal Kalra

Keyword(s):

Repeated Measures ◽

Medial Patellofemoral Ligament ◽

Suture Anchor ◽

Interference Screw ◽

T Test ◽

Mpfl Reconstruction ◽

Initial Stiffness ◽

Significant Difference ◽

Load To Failure ◽

Fresh Frozen

Background: There are numerous techniques for MPFL reconstruction, however, one single technique has not been proven to be superior to another. Suture anchor reconstruction has been shown to provide stable fixation while decreasing the risk of patellar fracture. The aim of the study was to compare the stiffness and clinical load to failure of two common MPFL reconstruction techniques. Our hypothesis was that there would be no significant difference in the stiffness and the clinical load to failure between the suture anchor and interference screw reconstructions. Methods: Eight pairs of fresh frozen cadaveric knees were randomized into two groups undergoing MPFL reconstruction using either a suture anchor technique (n=8) or an interference screw technique (n=8). Testing was performed at 0, 30, 60, and 90 degrees of flexion for the native knee, transected medial structures, and reconstructed MPFL. Next, the reconstructed MPFL specimens were tested until failure in 0 degrees of flexion. T test, One-Way ANOVA, and repeated measures of ANOVA were used for statistical analysis, P values less than 0.05 were considered significant. Results: The average stiffness for the suture anchor and interference screw reconstructions was 12.02 ± 3.96 N/mm and 14.21 ± 4.20 N/mm, respectively (t test, p = 0.27), while average clinical load to failure was 256.57 ± 54.1 N and 237.81 ± 23.82 N, respectively (t test, p = 0.38). There was no significant difference in stiffness between the suture anchor and interference screw techniques at 0, 30, and 60 degrees of flexion. Conclusions: The suture anchor and interference screw reconstruction techniques produce comparable stiffness for sub-failure testing at 0 and 30 degrees of flexion. For testing to failure, the initial stiffness for both reconstruction techniques have been shown to be concordant with previously published values for the native MPFL. Both reconstruction techniques provide greater ultimate failure loads than those reported for the native MPFL in previous studies. Clinical Relevance: Suture anchor reconstruction described in our study provides another reliable option for the reconstruction of the medial patellofemoral ligament. [Figure: see text]

Download Full-text