Load Response of the Hindfoot Bones in patients with the Ankle Osteoarthritis : in vivo 3D study

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Gyles Summers
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Graduate School of Medical Science, Kyoto Prefectural University of Medicine Department of Orthopaedic

1 Load Response of the Hindfoot Bones in patients with the Ankle Osteoarthritis : in vivo D study Hara Y, Ikoma K, Kido M, Imai K, Maki M, Takatori R, Tokunaga D, Inoue N,, Kubo T Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, USA Faculty of Life and Medical Science, Doshisha University, Kyoto, Japan

2 < Load Response of the Hindfoot Bones in patients with the Ankle Osteoarthritis: in vivo D study> < Yusuke Hara, Kazuya Ikoma, Masamitsu Kido, Kan Imai, Masahiro Maki, Ryota Takatori, Daisaku Tokunaga, Nozomu Inoue, Toshikazu Kubo> My disclosure is in the Final AOFAS Program Book. I have no potential conflicts with this presentation.

Introduction For osteoarthritis (OA) of ankle, the previous study

joint for the inversion deformity of the tibio-talar joint might

It is necessary to assess the flexibility of hindfoot.

3 Introduction For osteoarthritis (OA) of ankle, the previous study reported that the reduction of compensatory ability of subtalar joint for the inversion deformity of the tibio-talar joint might cause worsened ankle deformity. It is necessary to assess the flexibility of hindfoot. Purpose The purpose of this study was to quantify the D kinematics of hindfoot bones for OA of ankle in vivo.

The scans were performed using a custom-made loading device of the foot (Rakuhoku Prosthetic and Orthotic Manufacturing Co.

4 Fig. : custom-made loading device Fig. : D reconstructed image Methods Subjects ankles in 5 patients ( males and female, mean age, 65. years) with unilateral OA of ankle ( ankles at stage IIIb, ankles at stage IV). Computer Tomography (CT) CT was used to construct a model of hindfoot bones (tibia, talus and calcaneus). The scans were performed using a custom-made loading device of the foot (Rakuhoku Prosthetic and Orthotic Manufacturing Co., Ltd, Kyoto, Japan) that held the hip in 5 degree flexion, the knee in 9 degree flexion, and the foot in neutral positions. Setting up the vice between the foot and the knee, the load value was monitored with the scales on the kneepad. Pressure was applied by the vice with full body-weight (Fig. ). The images of the hindfoot bones were reconstructed into D model using CAD software (Mimics, Materialise Inc, Ann Arbor, MI) (Fig. ).

The volume merge method The volume merge method in three planes was used

tibia in the tibio-talar joint and the calcaneus relative to the talus in

The global x-y-z coordinate system was used to describe screw axis

Top Lateral Dorsiflexion (df) + Inversion (iv) - Posterior Plantarflexion

5 The volume merge method The volume merge method in three planes was used for calculating the rotation and translation of the talus relative to the tibia in the tibio-talar joint and the calcaneus relative to the talus in the tal-calcaneus (subtalar) joint (Fi. ). The global x-y-z coordinate system was used to describe screw axis orientation and position (Fig. ). Top Lateral Dorsiflexion (df) + Inversion (iv) - Posterior Plantarflexion (pf) - Y-axis Anterior Abduction (abd) + Z-axis Adduction (add) - Eversion (ev) + X-axis Medial Bottom Fig.: volume merge method Fig.: The definition of X,Y,Z axis

6 Results Tibio-talar joint X-axis (df+ /pf-) Y-axis (ev+ /iv-) Z-axis (abd+ /add-) (deg) (deg) (deg) ±.7.57±. -5.±..7±.86-5.±. -.±.7 normal -6-6 OA -7 normal OA -7 normal OA The relative bone motion of the talus to the tibia between OA of ankle and normal. There are no significant differences.

7 Tal-calcaneal joint X-axis (df+ /pf-) Y-axis (ev+ /iv-) Z-axis (abd+ /add-) (deg) (deg) (deg) * -.78±.7.8±.8.5.9±..86±.79.5 normal OA normal OA - normal OA ±. -.7±.9 The relative bone motion of the calcaneus to the talus for OA of ankle was more than that for normal ankle. (*: p<.5).

8 Discussions The pathogenesis of medial OA of ankle Disfunction of lateral ligament The varus deformity of distal joint surface of tibia The shift of total limb alignment Subtalar joint is important for ankle deformity. Cases in early stage of ankle OA :hindfoot valgus Valgus hindfoot alignment is compensation of medial ankle force. Cases in advanced stage of ankle OA :hindfoot varus Varus hindfoot alignment is the result of declining compensatory ability and makes ankle deformity worsened.

9 Our Report: Advanced OA cases Tal-calcaneal joint (subtalar joint) Eversion-inversion motion = conpensatory ability of hindfoot We find a decrease of subtalar joint motions within advanced stage of ankle OA using in vivo D kinematic analysis.

10 Conclusions We have evaluated the motion of hindfoot bones for OA of ankle. The kinematics of subtalar joint for OA showed a decline compared with normal ankle. The reduction of the hindfoot flexibility for OA of ankle was verified with failure of compensatory ability of subtalar joint. References [] Kitaoka, HB; et al.: Foot Ankle Int. 6: 9-99, 995. [] Imai, K; et al.: Foot Ankle Int. : 9-, 9. [] Hayashi, K; et al.: Foot Ankle Int. 9: -6, 8. [] Ochia, RS; et al.: Spine. : 778, 6.

Analysis of Mechanical Strength in Talus Using CT-osteoabsorptiometry; in vivo Study

Analysis of Mechanical Strength in Talus Using CT-osteoabsorptiometry; in vivo Study Yusuke Hara 1), Kazuya Ikoma 1), Masamitsu Kido 1), Kan Imai 1), Masahiro Maki 1), Daisaku Tokunaga 1), Nozomu Inoue