Effect of Pilot-Hole Size on the Pullout Strength of Flexor Digitorum Longus Transfer Fixed with a Bioabsorbable Screw

2007 ◽  
Vol 28 (10) ◽  
pp. 1078-1081 ◽  
Author(s):  
Brian G. Donley ◽  
Clinton Jambor ◽  
Ahmet Erdermier ◽  
James Sferra ◽  
Peter Cavanagh
Keyword(s):  
Insertion Site ◽  
Hole Size ◽  
Pullout Strength ◽  
Flexor Digitorum Longus ◽  
Interference Fit ◽  
Pilot Hole ◽  
Bioabsorbable Screw ◽  
Significant Difference ◽  
Eden Prairie ◽  
Flexor Digitorum

Background: Fixation of tendon transfers with a bioabsorbable interference-fit screw has several advantages over other fixation methods: decreased dissection, operative time, and blood loss; preservation of tendon length; no interference with radiographic studies; no need for implant removal; and no barrier to revision surgery. Whether strength of fixation is affected by the size of the pilot hole has not been established. The purpose of this study was to determine the effect of pilot hole size on the pullout strength of a flexor digitorum longus (FDL) tendon secured into a bone analog using a 5.5-mm bioabsorbable screw. Methods: Thirty FDL tendons were harvested from 15 cadaver specimens and secured into predrilled 4 times 4 × 4 cm bone cubes with a 5.5-mm Arthrex bioabsorbable screw (Arthrex, Naples, FL). The use of bone analog foam cubes ensured consistent porosity at the insertion site, eliminating the variations associated with varying bone densities of cadaver specimens. Pilot hole sizes studied were 5.0 mm, 5.5 mm, and 6.0 mm. Pullout tests were done with an servohydraulic testing frame (MTS, Eden Prairie, MN). Results: There was no significant difference ( p = 0.4) between the pullout forces and stresses among the three pilot hole sizes. All specimens failed at the interface between the FDL and the bioabsorbable screw. In the 6.0-mm pilot hole group, there was a trend for increased pullout strength with increased tendon size. Conclusions: With a bioabsorbable 5.5-mm screw used for FDL transfer, a pilot hole the same size or a half millimeter larger or smaller than the screw had no statistically significant effect on the strength of the construct, even with tendons of different sizes.

scholarly journals Anatomy of the Distal End of Flexor Digitorum Longus Tendon and Percutaneous Release Technique: A Cadaveric Study

2019 ◽  
Vol 4 (4) ◽  
pp. 247301141988427
Author(s):  
Baofu Wei ◽  
Ruoyu Yao ◽  
Annunziato Amendola
Keyword(s):  
Distal Phalanx ◽  
Neurovascular Bundle ◽  
Middle Phalanx ◽  
Flexor Digitorum Longus ◽  
Longus Tendon ◽  
Pull Out ◽  
Percutaneous Release ◽  
Significant Difference ◽  
Distal Interphalangeal ◽  
Flexor Digitorum

Background: The transfer of flexor-to-extensor is widely used to correct lesser toe deformity and joint instability. The flexor digitorum longus tendon (FDLT) is percutaneously transected at the distal end and then routed dorsally to the proximal phalanx. The transected tendon must have enough mobility and length for the transfer. The purpose of this study was to dissect the distal end of FDLT and identify the optimal technique to percutaneously release FDLT. Methods: Eight fresh adult forefoot specimens were dissected to describe the relationship between the tendon and the neurovascular bundle and measure the width and length of the distal end of FDLT. Another 7 specimens were used to create the percutaneous release model and test the strength required to pull out FDLT proximally. The tendons were randomly released at the base of the distal phalanx (BDP), the space of the distal interphalangeal joint (SDIP), and the neck of the middle phalanx (NMP). Results: At the distal interphalangeal (DIP) joint, the neurovascular bundle begins to migrate toward the center of the toe and branches off toward the center of the toe belly. The distal end of FDLT can be divided into 3 parts: the distal phalanx part (DPP), the capsule part (CP), and the middle phalanx part (MPP). There was a significant difference in width and length among the 3 parts. The strength required to pull out FDLT proximally was about 168, 96, and 20 N, respectively, for BDP, SDIP, and NMP. Conclusion: The distal end of FDLT can be anatomically described at 3 locations: DPP, CP, and MPP. The tight vinculum brevis and the distal capsule are strong enough to resist proximal retraction. Percutaneous release at NMP can be performed safely and effectively. Clinical Relevance: Percutaneous release at NMP can be performed safely and effectively during flexor-to-extensor transfer.

scholarly journals Relationship Between Insertion Torque, and Pullout Strength Depending on the Size of the Pilot Hole and Biodegradable Suture Anchor in Osteoporotic Humeral Head

2012 ◽  
Vol 15 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Yong Min Chun ◽  
Young Han Lee ◽  
Sung Hwan Kim ◽  
Yoo Jung Park ◽  
Sung Jae Kim
Keyword(s):  
Humeral Head ◽  
Suture Anchor ◽  
Region Of Interest ◽  
Insertion Torque ◽  
Pullout Strength ◽  
Mineral Density ◽  
Pilot Hole ◽  
Significant Difference ◽  
Group A ◽  
The Difference

PURPOSE: The object of this study was to investigate the difference in torque and pullout strength between the standard anchor insertion (5.0 mm) with a small awl (3.7 mm) and larger anchor insertion (6.5 mm), with a standard awl (5.0 mm) in osteoporotic humeral head.MATERIALS AND METHODS: The embalmed 24 paired cadaveric shoulders were assigned to either Group A or B. After measuring the bone mineral density (BMD) of the ROI (region of interest) in the humeral head, 5.0 mm suture anchors were inserted using a 3.7 mm awl in Group A1, and the same 5.0 mm anchors were inserted using a 5.0 mm awl in Group A2. The 5.0 mm anchors were inserted using a 5.0 mm awl in Group B1, and 6.5 mm anchors were inserted using a 5.0 mm awl in Group B2. We measured the torques at the time of the anchor insertion and pullout strengths.RESULTS: There was no significant difference in the BMD between the groups. The torque of A1 (20.6 cN.m) was significantly higher than that of A2 (13.2 cN.m), and the torque of B2 (20.8 cN.m) was significantly higher than that of B1(12.1 cN.m). However, the difference in the increased torque between group A and B was not significant. The pullout strength of A1 (204.2 N) was significantly higher than that of A2 (152.9 N), and the pullout strength of B2 (210.9 N) was significantly higher than that of B1 (149.5 N). However, the difference in the increased pullout strength between Group A and B was not significant.CONCLUSION: In severe osteoporosis, the use of a larger suture anchor with a standard awl increased the torque and pullout strength significantly, in comparison to the use of the same sized suture anchor and awl. If there is an inadequate interval between the anchors on the greater tuberosity, the use of a 3.7 mm awl and 5.0 mm anchor will be beneficial compared to that of a 5.0 mm awl and 6.5 mm anchor, considering that an increase in the pullout strength does not depend on the awl size.

Tendon Transfer Fixation in the Foot and Ankle: A Biomechanical Study Evaluating Two Sizes of Pilot Holes for Bioabsorbable Screws

2003 ◽  
Vol 24 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Keith W. Louden ◽  
Catherine G. Ambrose ◽  
Stacy G. Beaty ◽  
William C. McGarvey ◽  
Thomas O. Clanton
Keyword(s):  
Tendon Transfer ◽  
Biomechanical Testing ◽  
Biomechanical Study ◽  
Hole Size ◽  
Foot And Ankle ◽  
Pilot Hole ◽  
Initial Fixation ◽  
Significant Difference ◽  
Bioabsorbable Screws ◽  
Drill Holes

The purpose of this study was to compare the initial fixation strengths of bioabsorbable screws for tendon transfers in the foot and ankle when the pilot hole size varied. A 7times20 mm screw was used with 5.5 mm and 6.5 mm drill holes, and a 5times20 mm screw was used with 3.9 mm and 4.5 mm drill holes. Biomechanical testing was performed on each tendon transfer in cadaver specimens. A paired t-test showed no significant difference in pullout strength when pilot hole size varied between 79 to 93% of the screw size for the 7 mm screw and 78 to 90% of the screw size for the 5 mm screw. Previous studies have found a critical value of tendon tension equaling 50 N with passive dorsiflexion of the foot. With an average value of approximately 170 N, the 7 mm screw provided three times the requisite strength. The 5 mm screw provided 1.5 times the requisite strength, but the transfer was technically more difficult.

scholarly journals Presence of adipose tissue along the posteromedial tibial border

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Okunuki Takumi ◽  
Tanaka Hirofumi ◽  
Akuzawa Hiroshi ◽  
Yabiku Hiroki ◽  
Maemichi Toshihiro ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Gross Anatomy ◽  
Medial Malleolus ◽  
Posterior Tibial Tendon ◽  
Flexor Digitorum Longus ◽  
Significant Difference ◽  
Fat Fraction ◽  
Flexor Digitorum ◽  
Fat Pads

Abstract Purpose The flexor digitorum longus and posterior tibial tendon as well as the perforating veins are located along the distal posteromedial tibial border. Adipose tissue may surround these structures and possibly play a role in reducing mechanical stress. This study aimed to examine the adipose tissue along the posteromedial tibial border via magnetic resonance imaging (MRI), ultrasound, and gross anatomical examination. Methods The lower legs of 11 healthy individuals were examined every 3 cm from the medial malleolus using MRI and ultrasound. The fat fraction was calculated using fat fraction images. In addition, the gross anatomy of the flexor digitorum longus origin and adipose tissue along the posteromedial tibial border was examined in seven fresh cadavers. The fat fraction was compared at different heights along the posteromedial tibial border and in Kager’s fat pads; we also compared the height of the flexor digitorum longus origin and adipose tissue. Results In vivo, the adipose tissue was identified along the entire posteromedial tibial border using MRI and ultrasound. There was no significant difference in fat fraction between Kager’s fat pads and the adipose tissue along the posteromedial tibial border, except at the 6 cm mark. All seven cadavers presented adipose tissue along the posteromedial tibial border, significantly more distal than the flexor digitorum longus origin. Conclusion The adipose tissue was identified along the posteromedial tibial border via MRI, ultrasound, and gross anatomical examination; thus, this tissue may play a role in reducing friction and compressive stress in tendons.

scholarly journals Biomechanical Comparison of Fixation Stability among Various Pedicle Screw Geometries: Effects of Screw Outer/Inner Projection Shape and Thread Profile

2021 ◽  
Vol 11 (21) ◽  
pp. 9901
Author(s):  
Ming-Kai Hsieh ◽  
Yun-Da Li ◽  
Mu-Yi Liu ◽  
Chen-Xue Lin ◽  
Tsung-Ting Tsai ◽  
...  
Keyword(s):  
Bone Density ◽  
Pedicle Screw ◽  
Cylindrical Shape ◽  
Hole Size ◽  
Pullout Strength ◽  
Pilot Hole ◽  
Insertional Torque ◽  
Fixation Stability ◽  
Biomechanical Comparison ◽  
Screw Threads

The proper screw geometry and pilot-hole size remain controversial in current biomechanical studies. Variable results arise from differences in specimen anatomy and density, uncontrolled screw properties and mixed screw brands, in addition to the use of different tapping methods. The purpose of this study was to evaluate the effect of bone density and pilot-hole size on the biomechanical performance of various pedicle screw geometries. Six screw designs, involving three different outer/inner projections of screws (cylindrical/conical, conical/conical and cylindrical/cylindrical), together with two different thread profiles (square and V), were examined. The insertional torque and pullout strength of each screw were measured following insertion of the screw into test blocks, with densities of 20 and 30 pcf, predrilled with 2.7-mm/3.2-mm/3.7-mm pilot holes. The correlation between the bone volume embedded in the screw threads and the pullout strength was statistically analyzed. Our study demonstrates that V-shaped screw threads showed a higher pullout strength than S-shaped threads in materials of different densities and among different pilot-hole sizes. The configuration, consisting of an outer cylindrical shape, an inner conical shape and V-shaped screw threads, showed the highest insertional torque and pullout strength at a normal and higher-than-normal bone density. Even with increasing pilot-hole size, this configuration maintained superiority.

Absorbable Sutures in Tendon Repair

1995 ◽  
Vol 20 (4) ◽  
pp. 505-508 ◽  
Author(s):  
E. S. O’BROIN ◽  
M. J. EARLEY ◽  
H. SMYTH ◽  
A. C. B. HOOPER
Keyword(s):  
Tensile Strength ◽  
Rabbit Model ◽  
Tendon Repair ◽  
Tendon Healing ◽  
Flexor Digitorum Longus ◽  
Absorbable Sutures ◽  
Significant Difference ◽  
Intact Rabbit ◽  
Flexor Digitorum

The risks of foreign implantation may be avoided in tendon repair by the use of absorbable sutures, for example polydioxanone. In this study, the in vivo tensile strength half-life of 4/0 polydioxanone was found to be approximately 4 weeks. Using a rabbit model, we compared polydioxanone tendon repairs with polypropylene tendon repairs. Unilateral flexor digitorum longus repairs were performed on 46 rabbits using either polydioxanone or polypropylene. Tendons were harvested at 3 days, 2 weeks and 4 weeks and the tensile breaking strengths were obtained. 30 intact rabbit flexor digitorum longus tendons and 20 freshly repaired tendons were also tested. By 4 weeks, the repair strength had increased eight-fold from approximately 20 N to 166 N. The sutures made little contribution to the overall strength of a 4-week-old repair. There was no significant difference between polydioxanone and polypropylene repairs at any stage. These results show that polydioxanone repairs were as strong as polypropylene during the first critical weeks of tendon healing.

The Effect of Pilot Hole Size on the Insertion Torque and Pullout Strength of Self-Tapping Cortical Bone Screws in Osteoporotic Bone

2008 ◽  
Vol 64 (4) ◽  
pp. 990-995 ◽  
Author(s):  
Suneel Battula ◽  
Andrew J. Schoenfeld ◽  
Vivek Sahai ◽  
Gregory A. Vrabec ◽  
Jason Tank ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Bone Screws ◽  
Osteoporotic Bone ◽  
Insertion Torque ◽  
Hole Size ◽  
Pullout Strength ◽  
Pilot Hole

An Anomalous Leg Flexor Muscle

1993 ◽  
Vol 1 (1) ◽  
pp. 50-51
Author(s):  
Lowell A Hughes ◽  
James L Mahoney
Keyword(s):  
Normal Anatomy ◽  
Flexor Muscle ◽  
Flexor Digitorum Longus ◽  
Leg Muscles ◽  
Posterior Group ◽  
Flexor Digitorum

LA Hughes, JL Mahoney. An anomalous leg flexor muscle. Can J Plast Surg 1993;1(1):50-51. A case of an anomalous flexor muscle in the leg (flexor digitorum intermedius) is described and the normal anatomy of the flexor digitorum longus discussed along with known variations and abnormal muscles in the deep posterior group of leg muscles.

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