yogabook / pathologie / rupture of the plantar plate

Tear or complete rupture of the plantar plate under (plantar) the metatarsophalangeal joints. In addition to tears and ruptures, degenerative changes with thickening also occur. The classification system according to Thompson and Hamilton differentiates between five degrees of subluxation of the proximal phalanx:

• G0: stable joint with pain but no deformity.
• G1: slight instability of the joint (subluxation less than 50 %), pain, swelling, widening of the space between the toes
• G2: moderate instability (subluxation over 50 %), medial, lateral, dorsal or dorsomedial joint deformity, hyperextension of the toes. Pain, no or little swelling.
• G3: Severe instability (ability to dislocate ): dorsal or dorsomedial deformity, digitus secundus superductus, possibly flexible claw toe, joint and foot pain, little or no oedema.
• G4: Dislocation: severe deformity, fixed claw toe. Joint and foot pain, little or no oedema.

Causes

acute traumatic causes:

• Repeated microtrauma can lead to inflammation, weakening and eventually rupture of the plantar plate.
• traumatic: fractures of the sesamoid bones, sesamoiditis (which has a chronic tendency to sclerosis), osteonecrosis or diastasis of a split sesamoid bone (Os sesamoideum bipartitum), loose osteochondral fragments after cartilage injury
• Turf toe: Hyperextension trauma of the metatarsophalangeal joint, especially with plantar flexion of the ankle joint (upper ankle joint)
• Injuries to the two bones involved in MTP (proximal phalanx and metatarsal head) in dorsiflexed MTP
• Jumps from great heights
• Sports and activities that put pressure on the forefoot: Sprinting, dancing (ballet)

degenerative causes:

• Hallux valgus
• Osteoarthritis of the MTP

other causes:

• Hyperpronation

Predispositions

• short metatarsal bone 1
• long metatarsal bone 2

Symptoms

• Instability of the MTP
• possibly Digitus superductus
• Subluxation and dislocation tendency
• Load-dependent pain
• Pressure soreness
• Symptoms of nerve congestion syndrome of the plantar digital nerves: numbness of the medial sole of the foot, pressure pain in the heel
• Swelling extending to the toes
• If necessary, widening of the space between the toes (toe gapping sign, „victory sign“, „Churchill sign“)
• Loss of ground contact of the toe
• concerning the little toe: Deformity of the little toe

Diagnosis

• X-rays show sunken metatarsal bones
• Sono, dynamic more accurate than static
• MRI
• CT for suspected soft tissue injuries
• Test and signs: plantar and dorsal drawer test. The plantar drawer test can produce a plopping sound that indicates a diagnosis. Plantar gripping test: an 8*1 cm strip of paper previously placed under the second toe cannot be gripped with the toe if the test is positive. Reverse Windlass test: inability of the affected toe to flex the plantar flexion when standing on an elevation. Manual testing of the muscle strength of the intrinsic flexors and the flexor digitorum longus.

Complication

• Hammer toe
• Dislocation in the MTP

Therapy

• Avoid barefoot running and high heels as well as flexible, minimalist shoes (barefoot shoes, flip-flops, etc.). Instead, a rather stiff shoe with a firm sole is worn, possibly also a shoe that encourages rolling (roll-off shoe, rocker shoe)
• depending on the condition: Insoles, taping, toe spreader
• Plasters to restrict the dorsiflexion of the MTP
• Mobilisation of the metatarsus, strengthening of the intrinsic foot muscles and the extrinsic plantar flexors of the toes
• Shock wave therapy
• Cortisone: caution, can damage the plantar plate
• OP: complex operation, long rehabilitation