UNDERWATER ROCK OF THE
LIGAMENTUM TERES RECONSTRUCTIONS

Sergey V. Arkhipov

Dedicated to Reconstructors of Ligamentum Teres

INTRODUCTION:
Our colleagues made a wonderful presentation: LT_PHILIPdoNOTlostIT_dicatate.mov, Philip Rosinsky et al., - Thanks!

PURPOSE:
Here I would like to recall one of the underwater rock on the way of the ligamentum teres reconstructions.

PREMISS:
Distribution of forces in the hip joint in the monopodial standing position and in the single limb stance phase of normal gait is complicated and not obvious.

Fig.1 Distribution of forces in the single limb stance phase of normal gait (Arkhipov S.V., 2019)

PROBLEM:
What is the load on the ligamentum teres?

CONDITIONS OF THE PROBLEM:
Acceleration of gravity, g = 9.8 m s^-2
Overall of the body mass = 58.7 kg, see experiment of O.Fischer (Pauwels F, 2012, P.86)
Body mass (single limb support period) according to Fischer O. = 47.76 kg (Pauwels F., 2012, P.86)
The maximum dynamic component is the 17th phase of the step (dynamic force) +24.35 kg (Pauwels F., 2012, P.87)
Lever arm of the body weight = 0.1099 m (Pauwels F., 2012, P.83)
Lever arm of the abductor muscles = 0.04 m (Pauwels F., 2012, P.85)
Kapandji A.I.(2009): m. gluteus medius can develop force - 16 kg, m. gluteus minimus - 4.9 kg, m.
tensor fascia lata - 7.6 kg; i.e. in total the abductor muscle group can develop generate = 28.5 kg.
Diameter of the femoral head = 0.05 m (circa)
Fossa acetabulum depth 0.01 m (circa)
Bottom thickness of the fossa acetabulum = 0.003 m (circa)

SOLUTION OF THE PROBLEM:
Rule of moments for a single support step period Arkhipov S.V. (2019):

PL = F_abL_ab + F_ltL_lt

Body weight (body mass + dynamic force × g) in the 17th phase of the step:

P = (47.76 + 24.35) × 9.8 = 706.68 N

Lever arm of the ligamentum teres (half diameter of the femoral head + fossa acetabulum depth + Bottom thickness of the fossa acetabulum):

L_lt = 0.05/2 + 0.01 + 0.003 = 0.038 m

Abductor force (pull of the abductor muscle × g):

F_ab = 28.5 × 9.8 = 279.3 N

The ligamentum teres load:

F_lt = (PL - F_abL_ab) / L_lt

F_lt = (77.66 - 11.17) / 0.038 = 1749.74 N

UNDERWATER ROCK:
The loading of the ligamentum teres during walking may be equivalent 178.54 kg, that is 3 times more of the overall body mass.

QUESTION: 

Fig. 2 Presentation of the Rosinsky P. et al., 2019  (video: right – 01 m. 13 s. ; left – 01 m. 18 s.)

Can this thread, button and bottom of the acetabulum withstand a load of 178.54 kg and how long?

ACKNOWLEDGMENTS
My good wishes for success to colleagues: Philip Rosinsky, Jacob Shapira, Ajay C. Lall, and Benjamin G. Domb.

References

1. Rosinsky P., Shapira J., Lall A.C., Domb B.G. (2019) LT_PHILIPdoNOTlostIT_dicatate.mov. Retrieved December 23, 2019. from
https://www.researchgate.net/publication/338112825_LT_PHILIPdoNOTlostIT_dicatatemov
2. Arkhipov S.V. (2019, September 22) New Biomechanics of the Hip Joints: Ligamentum Teres as a Functional Relation. Part I. Pictorial Essay. Ligamentum Teres – Ligamentum Incognitum. Vol. 0, № 0, pp. 1–25. Retrieved December 23, 2019. from
https://www.ligteres.com/statyi/new-biomechanics-of-the-hip-joint-part-1-pictorial-essay
3. Pauwels F. Biomechanics of the locomotor apparatus: contributions on the functional anatomy of the locomotor apparatus. Berline [etc.], Springer Science & Business Media, 2012.
4. Kapandji A.I. The physiology of the joints: Lower limb. Vol. 2, 5th ed. New Delhi: Elsevier Exclusive, 2009.