Mechanical Assessment of Tripled Hamstring Tendon When Using Suspensory Fixation for Cruciant Ligament Reconstruction-Dr. I. Geethan

1. Mechanical assessment of
tripled hamstring tendon
when using suspensory
fixation for cruciate ligament
reconstruction
DR. GEETHAN I MS(ORTH) DNB(ORTH)

2. Triple = trouble?

3. Co-Authors
 Dr. David V Rajan
 Dr. Clement J Joseph
 Dr. Santhosh Sahanand
 Dr. Ashwin Vijay
No conflicts of interest in the authorship and presentation of
this paper.

4. Background
 ACL reconstruction is one of the commonly performed arthroscopic
procedures
 Hamstring graft is used by many surgeons
An international survey on anterior cruciate
ligament reconstruction practices
Chechik et al, SICOT 2013

5. Why triple?
 Usual length of semitendinosus tendon is 28 –
32 cm.
 Double 15 cm
 Triple 10 cm
 Quadruple 7-8 cm
2 cm
4 cm
2.5- 3 cm
Total 9 cm
Chiang et al, KSSTA 2012
Triple without trouble, IASCON 2014

6. Lavery et al, Arthroscopy Techniques 2014 (3)
Lee KSSTA 2013
Snow et al KSSTA 2012
Strobel. Manual of
Arthroscopy
Triple without trouble, IASCON 2014

7. What’s the trouble?
 The preferred femoral fixation option is Suspensory fixation
Triple without trouble, IASCON 2014

8. Snow et al, KSSTA 2012
 Compared tripled tendon to
double
 Found no benefit with triple
spite of increased thickness
 Recommended against tripling
Triple without trouble, IASCON 2014

9. Many methods of tripling
Snow et al KSSTA 2012
Lavery et al, Arthroscopy Techniques 2014 (3)
Triple without trouble, IASCON 2014
Lee KSSTA 2013
Strobel. Manual of
Arthroscopy

10.  Purpose
 To compare to mechanical properties of tripled graft prepared
by three different methods
 Hypothesis
 Tripled graft will have variable mechanical properties
depending on the way of preparation
Triple without trouble, IASCON 2014

11. Materials
Similar structural and mechanic properties as young adult
Bovine hind foot hoof extensor tendon
Triple without trouble, IASCON 2014

12. Tripled Graft Configurations
Group I
Group II Group III Group IV

13. Test Construct
• InstronMaterial testing
system- fully automated
• All parameters entered into
software
• All data measured by the
system and read off the
computer screen, and
output print out
Triple without trouble, IASCON 2014

14. Mechanical assessment
Test Protocol
 Preloading
 10 to 50 N at 0.1 Hz for 10 cycles
 Cyclic Loading
 1000 cycles ; 50 and 250N at a frequency of 0.5 Hz.
 Distraction to failure
 50mm/min
As reported by Petre et al, AJSM; 2013

15. Results

16. Displacement
 Group I Groups 1.13 ± 0.11 Observed mm
‘t’
 Group II 4.91 ± value
0.49 mm
Displacement I Vs. II 16.92 3.355 ( p = 0.01) p < 0.01
 Group III 1.822 ± 0.55 mm
I Vs. III 11.15 3.355 ( p = 0.01) p < 0.01
 Group IV 1. 126 ± .018 mm
Table ‘t’ value ‘p’ value
I Vs. IV 0.044 1.806 ( p = 0.10) P > 0.10
 All samples survived cyclical loading
3mm is considered acceptable displacement
Daniel DM, Stone ML, Sachs R, Malcom L. Instrumented measurement of anterior
knee laxity in patients with acute anterior cruciate ligament disruption. Am J Sports
Med. 1985;13(6):401-407

17. Ultimate load at failure
Groups Observed ‘t’
Table ‘t’ value ‘p’ value
 Group I 957 ± 23.30 N
value
 Group II 590.8 ± 26.55 N
I Vs. II 24.27 3.355 ( p = 0.01) p < 0.01
 Group III 682.6 ± 59.28 N
 Group IV 963.4 ± 21.72 N
Load at
failure
I Vs. III 9.63 3.355 ( p = 0.01) p < 0.01
I Vs. IV 0.45 1.806 ( p = 0.10) P > 0.10
Grafts may be subjected to loads of
upto 600N during normal rehabilitation
Ettinger M, Petri M, Kwisda S, Krettek C, Jagodzinski M. Biomechanical
Considerations for Graft Fixation in ACL Reconstruction. Techniques in Orthopaedics.
2013;28(2): 126-132.

18. Mode of failure
Group I Group IV
Triple without trouble, IASCON 2014

19. Mode of Failure
Group II Group III

20. Prior studies…Snow et al, KSSTA
2012
 No difference between double and triple
 All the failures at interference screw
 Uneven distribution of load across three strands
Triple without trouble, IASCON 2014

21. Advantages of this study
 Compares three different techniques of tripling
 Isolated the graft-loop interface
 Suspensory fixation device, Graft thickness and
length standardised
Triple without trouble, IASCON 2014

22. Limitations
 Tibial fixation is with a vice grip
 In vitro study
 Loading represents extreme case scenario
 Unidirectional loading
 Role of graft healing is not studied
 Stiffness is not reported
 Differential loading is not studied
Triple without trouble, IASCON 2014

23. Conclusions
 Hypothesis that tripled tendon configuration have variable
mechanic properties is found true.
 Triple strand configurations studied in Group II and Group III
in our study are significantly mechanically inferior.
 Suturing the three strands together as in Group IV has
equivalent mechanical properties as quadrupled strand in
our controlled laboratory study
Triple without trouble, IASCON 2014

24. Triple without trouble?
 What this study tells the surgeon?
 Tripled grafts have variable mechanical properties and the
surgeon should consider the inferior mechanical properties
while choosing to triple graft.
 Surgeon should consider suturing the three strands of graft
together increase ultimate failure load.

25. Thank You