• Orthopaedics Clinical Trials
• Orthopaedic Procedures
• Foot & Ankle Conditions

• Orthopaedics Clinical Trials
• Orthopaedic Procedures
• Foot & Ankle Conditions
• Orthopaedics

Umur Aydogan, MD, Penn State Hershey, Hershey, Pennsylvania, USA, presented data showing that when compared with classic and modified Weil osteotomy, proximal oblique dorsiflexion osteotomy (PODO) is more effective in reducing average and peak pressures under the second metatarsal.

Most metatarsalgia can be relieved with shoe modifications and orthotics; however, resistant cases may need surgery. Surgical options for these patients include plantar condylectomy, Weil osteotomy, modified Weil osteotomy, and PODO. Only a few studies have evaluated these approaches. However, none (1) used loading more complex than axial force on the tibia, (2) directly compared all the approaches, or (3) included Achilles tension. Dr Aydogan presented results from a study that compared the effects of the classic Weil, modified Weil, and PODO in specimens obtained from cadavers, on the basis of physiologic loading of the tibia under a variety of Achilles tendon tensions.

Specimens (6 left-right pairs of feet; 9 women; 3 men) from cadavers with an average age of 51.3 years were prepared by removing the tissue around the distal tibia to the bone (about 4 in) and exposing and stripping the Achilles tendon of muscle. The distal tibia was then potted with chemical cement in ∼ 3 in of PVC pipe, which was then fixed with screws in a fixture on the material testing system. This process also generated the downward force (445 N) on the tibia to simulate bodyweight (100 lb). The foot rested on the center of the pressure pad, which was clamped to a load cell used to ensure that the downward force remained constant. The load cell was fixed to a bearing platform, which allowed the foot to settle into a natural position. The exposed Achilles tendon was attached to a cable via a liquid-nitrogen freeze clamp. The line of action of the cable approximated the physiologic angle of the Achilles and was attached to a load cell and pneumatic actuator used to generate the force on the Achilles tendon (0, 300, 600 N).

Six feet received classic Weil procedures, followed by modified Weil osteotomies; 6 received PODO. Surgeries were evenly split between foot orientation and sex. Measurements were taken before treatment and after each surgery for Achilles force (0, 300, anatomy check, and 600 N). All 5 metatarsals were regions of interest. Average pressure, peak pressure, and contact area were measured.

There was no decrease in second metatarsal average pressure with classic Weil; there was a trend toward a reduction in pressure in the second metatarsal with the modified Weil, but the difference was not significant. PODO was associated with a significant decrease in pressure in the second and third metatarsals and an increase for the first metatarsal, compounded by high loading of the Achilles tendon.

Dr Aydogan concluded that PODO is the most effective surgery for reducing average and peak pressures under the second metatarsal. The Weil osteotomy with and without modification did not significantly change plantar pressure beneath the second metatarsal and may be effective through an alternate mechanism. Increasing Achilles tension increases the second metatarsal plantar pressure. In cases where the Achilles tendon is tight, lengthening may increase the effect of the procedures, especially in PODO.

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