Medial Malleolar Osteotomy Approach to the Talar Dome

What it exposes. The medial malleolar osteotomy gives direct, perpendicular access to the posteromedial talar dome by temporarily detaching the medial malleolus and reflecting it distally on its deltoid ligament pedicle. It converts an otherwise hidden posteromedial lesion into a directly visible working surface. Why this approach. The medial talar dome is concealed beneath the overhanging medial malleolus, and the great majority of medial osteochondral lesions sit posteriorly. Arthroscopic instruments cannot be directed perpendicular to a posteromedial lesion without forcing the ankle into an unnatural position, and angling a graft or drill off the perpendicular damages both the recipient cartilage and the graft. Osteotomizing the malleolus restores perpendicular working access, and the osteotomy is itself rigidly re-fixed at the end.

Primary indications - Posteromedial osteochondral lesions of the talar dome that cannot be accessed arthroscopically because the medial malleolus overhangs the dome and the lesion sits behind it

• Osteochondral autograft transfer (OAT, mosaicplasty) where perpendicular plug harvest and insertion is mandatory
• Osteochondral allograft (OCA) reconstruction for large or uncontained medial defects
• Autologous chondrocyte implantation (ACI, MACI) requiring an open arthrotomy for membrane or matrix placement
• Internal fixation of a large osteochondral fragment in situ
• Bone grafting of a symptomatic subchondral cyst of the medial dome Contraindications - A lesion fully accessible arthroscopically (typically anterior or central medial) - an osteotomy is then unnecessary morbidity
• Active septic arthritis or local soft tissue infection over the medial ankle
• Advanced tibiotalar arthritis (arthroplasty or arthrodesis is more appropriate)
• A non-compliant patient unlikely to protect the osteotomy during healing
• Severe peripheral vascular disease threatening wound and fragment healing Alternative approaches and lesion access strategy. Arthroscopy with dorsiflexion-plantarflexion manoeuvres is first-line for accessible lesions and bone marrow stimulation; an anteromedial arthrotomy alone suits purely anterior medial lesions; and a posteromedial arthrotomy (between FHL and the flexor tendons) addresses true posterior lesions without osteotomy in selected cases. The medial malleolar osteotomy is the workhorse for the deep posteromedial dome when perpendicular access is needed.

Position and landmarks. The patient is supine with the leg externally rotated so the medial face of the ankle points toward the ceiling - no repositioning or prone setup is required. Apply a well-padded high thigh tourniquet and exsanguinate to a bloodless field; a bump under the ipsilateral buttock holds external rotation. Place the foot at the foot of the table so the image intensifier can obtain true AP, mortise and lateral views. Confirm ankle dorsiflexion and plantarflexion are free, as both are used to expose the dome, and protect all bony pressure points.

Surface anatomy. The medial malleolus is the palpable subcutaneous prominence that centres the incision. The tibialis posterior tendon sits in the groove immediately behind the malleolus and the tibialis anterior tendon marks the anteromedial corner. The sustentaculum tali is palpable about one fingerbreadth below the malleolar tip. The great saphenous vein and saphenous nerve run together subcutaneously a fingerbreadth anterior to the malleolus, and the fan-shaped deltoid ligament passes from the malleolus to the talus, navicular and calcaneus. The posteromedial neurovascular bundle (posterior tibial artery and tibial nerve) lies in the tarsal tunnel behind the posterior tibial tendon. Incision planning. A curvilinear or gently J-shaped incision is centred on the medial malleolus. It begins roughly 5 cm proximal to the malleolar tip along the anterior border of the tibia, curves distally and posteriorly around the malleolus toward the medial gutter, and runs 8 to 10 cm depending on exposure. It stays anterior to the tibialis posterior tendon sheath and posterior to the tibialis anterior tendon.

Work down through the layers onto the medial malleolus, protecting the saphenous nerve anteriorly and the posterior tibial tendon posteriorly, pre-drill the refixation tracks, cut the deltoid-preserving chevron, then reflect the malleolus distally like a book to expose the posteromedial dome.

Structures at risk, by layer

Osteotomy geometry variants

Extensile options. Extend proximally along the anterior tibial border to address distal tibial articular or metaphyseal pathology (tracking the saphenous nerve along its whole course), or distally toward the medial gutter or sustentaculum tali to reach the talonavicular joint or the posterior tibial tendon insertion. For borderline-accessible lesions, arthroscopy can be combined with a limited arthrotomy and a small localised "window" corticotomy of the malleolus rather than a full osteotomy, sparing the deltoid pedicle in selected cases. Closure and immobilisation. Copious saline irrigation; meticulous haemostasis taking care not to injure the saphenous nerve or the posteromedial bundle. The defining step is anatomic refixation through the pre-drilled tracks with two divergent cancellous screws (add an anti-rotation K-wire or small plate if rotation is uncertain), confirmed on fluoroscopy. Close in layers - anterior capsule and periosteal sleeve, retinaculum and posterior tibial sheath, subcutaneous tissue, then skin - and apply a short-leg posterior splint or cast in neutral. Rehabilitation timeline. - Weeks 0 to 2: Splint, elevation, non-weight-bearing, toe movement.

• Weeks 2 to 6: Suture removal, transition to a walking boot or cast, continue non-weight-bearing to protect the cartilage repair.
• Weeks 6 to 12: Progressive weight-bearing as the osteotomy unites, supervised physiotherapy for ROM and proprioception.
• Months 3 to 6: Full weight-bearing and strengthening, return to impact guided by imaging and symptoms.
• Beyond 6 months: Gradual return to sport once the graft has matured. Follow-up radiographs at 2 weeks (alignment and hardware), 6 weeks (early osteotomy union) and 3 months (union and graft incorporation); MRI may be used selectively if symptoms persist.

The osteotomy exists to deliver perpendicular access to the posteromedial dome. The cartilage procedure chosen is dictated by the lesion's size, containment and Berndt and Harty stage.

Berndt and Harty staging and how it guides the medial dome

Cystic and uncontained lesions. Subchondral cysts require curettage and bone grafting through the osteotomy. Uncontained (wall-deficient) lesions need OCA or ACI rather than OAT, and large-diameter lesions (greater than approximately 15 mm) favour allograft over multiple small autograft plugs.

Guidelines, Registries and Global Practice Management of osteochondral lesions of the talus is converging worldwide across examination systems: posteromedial lesions of the medial dome require an osteotomy or posterior arthrotomy for perpendicular access when open cartilage restoration is indicated, while bone marrow stimulation remains first-line for small contained lesions and OAT, osteochondral allograft and autologous chondrocyte implantation are reserved for larger or failed lesions.

Global practice variation. In high-resource settings, medial malleolar osteotomy with autograft, allograft or cell-based reconstruction is standard for posteromedial lesions. In resource-limited settings, microfracture through a mini-open or arthroscopic route is emphasised, and the osteotomy with autograft is reserved for larger lesions where the additional morbidity is justified. Consent (globally applicable). Discuss saphenous nerve injury and numbness, the common need for later hardware removal, osteotomy nonunion, ankle stiffness, infection, wound problems, and the possibility that the cartilage repair may fail and require a second-stage allograft or arthroplasty.