Introductory remarks
Surgical principles and objective
Advantages
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Preservation of the hyaline cartilage
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High-quality subchondral bone repair by bone marrow stimulation and additional cancellous bone grafting
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Excellent exposure
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No harvest site complications with distal tibia grafting, minimal harvest site complications in iliac crest grafting
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Other surgical salvage options remain possible in case of failed fixation
Disadvantages
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Access through distal tibia osteotomy
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Potential hardware complications which may lead to the need for hardware removal procedure
Indications
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Symptomatic osteochondral lesion with a fixable fragment situated on the medial talar dome with a minimum size of > 10 mm diameter and 3 mm in depth measured on CT scan [17]
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Contraindications: systemic disease, including active bacterial arthritis, hemophilic or other diffuse arthropathies, rheumatoid arthritis of the ankle joint, and malignancies
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Neuropathic disease
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End-stage ankle osteoarthritis or Kellgren and Lawrence score 3 or 4 [3]
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Ipsilateral medial malleolus fracture less than 6 months prior
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Relative contra-indication: posttraumatic ankle stiffness with ROM < 5°
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Children with open physis: do not perform an osteotomy as stabilization of the osteotomy may lead to early closure of the physis potentially resulting in symptomatic varus angulation of the distal tibia. In these cases only arthrotomy can be considered.
Patient information
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Surgical risks include infection, hematoma, thromboembolic events, wound healing problems, and transient or permanent nerve damage leading to hypaesthesia of the saphenous nerve.
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Non-weightbearing cast for 5 weeks, followed by a walking boot for another 5 weeks. Hereafter, patient individualized rehabilitation 3–6 months after cast removal guided by a physical therapist
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Late or early screw discomfort requiring removal after consolidation
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Adverse treatment events include fragment delayed—or nonunion, or osteotomy delayed—or nonunion
Preoperative work-up
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Clinical evaluation, including patient history and physical examination is performed for all patients at the outpatient clinic in order to assess symptoms befitting an OLT. Additionally, care is taken to assess any relevant coexisting pathologies of the foot and ankle which may warrant treatment, such as symptomatic ankle instability which is frequently encountered in patients with OLT [1, 22].
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Radiological assessment of the lesion is preferably carried out through a preoperative computed tomography (CT) scan to assess the three-dimensional lesion and fragment size, lesion location, as well as the lesion and fragment morphology.
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Additionally, the CT scan is used for preoperative planning in order to determine the surgical approach and osteotomy orientation based on the lesion location as well as to assess the need for additional debridement and filling of possible cysts situated below the osteochondral fragment. In case additional cancellous bone is required to fill the lesion site before fixation cancellous bone grafts can be obtained from the distal tibial metaphysis after osteotomy, or the iliac crest as described in a previously published surgical technique [4].
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Lastly, clinical and radiographic work-up by means of weightbearing x‑ray should be conducted in cases of suspected hindfoot malalignment as it may be necessary to address these concomitantly [18].
Instruments and implants
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Standard orthopaedic set
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Hohman retractors
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Bone rongeur
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Oscillating saw
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Chisel set (including thin blades)
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2.0 mm Kirschner wires
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2.0 mm drill
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Coagulation knife
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3.5 mm cortical screws or a headless alternative
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Large Weber clamps
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Screw or biomaterials for fragment fixation, not limited to, but options including depending on fragment size and surgeon preference:
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Bio-Compression screw 2.7 mm (Arthrex Inc., Naples, FL, USA) or poly-L-lactide pins (GRAND FIX, Depuy, USA)
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Autologous bone pegs harvested from the distal tibia
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(multiple) chondral darts 1.3 mm (Arthrex Inc., USA), to be used only as an antirotational post, a dart will not give sufficient compression in itself.
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Self-tapping 2.0 or 2.7 mm cortical screw (Johnson & Johnson, USA)
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Anaesthesia and positioning
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General or spinal anaesthesia
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Patients are placed in a supine position with a thigh tourniquet ipsilaterally
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Preoperative antibiotic prophylaxis with 2 g (or adjusted to weight) of cefazolin is administered intravenously
Special surgical considerations
Postoperative management
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A short leg cast is applied with nonweightbearing for 5 weeks postoperatively and antithrombotic prophylaxis is prescribed for this period. All casts are set in neutral flexion and hindfoot position. One to two weeks postoperatively the non-weightbearing casts consists of a splint to allow for swelling, followed by a circular cast for the remaining time of immobilization. The sutures are removed 2 weeks postoperatively combined with a change of the short leg cast.
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At 5 weeks postoperatively the non-weightbearing cast is exchanged for a short leg walking cast and weightbearing is allowed as tolerated. This cast is applied for 5 weeks.
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Radiographic follow-up with conventional anteroposterior and lateral X‑rays is performed at 5 weeks postoperatively before protected weight-bearing is commenced to reaffirm positioning of the osteotomy. At 10 weeks and 1‑year postoperatively a CT scan is performed in order to assess osteotomy consilidation, fragment consolidation and cyst formation or onset/progression of osteoarthritis (Fig. 11).
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After casting, a patient-centred rehabilitation protocol is started, guided by a physical therapist in order to regain range of motion and muscle strength of the ankle, as well as a normal gait pattern.
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Clinically, the patient is assessed postoperatively. We recommend a follow-up visit at 2, 5, and 10 weeks postoperatively for casting, wound healing, and osteotomy/fragment union consolidation, as well as 6 months and 1 year postoperatively for physical follow-up.
Errors, hazards, complications
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No available CT scan within 1 year of surgery could yield inadequate information regarding the morphology or size of the OLT and osteochondral fragment
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Inadequate exposure
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No perpendicular screw fixation leading to shallow insertion angle and inadequate compression of the fragment; leading to a higher chance of delayed or nonunion
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Screw size unfit for the fragment size, causing the fragment to break into smaller fragments requiring a salvage procedure (i.e. other OLT surgical treatment) or inadequate compression in larger fragments
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Fragment stabilization or screw too proud (i.e., above the articular cartilage), leading to (early) wear of tibiotalar cartilage
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Weightbearing too early postoperatively leading to higher risk of osteotomy or fragment nonunion or pseudoarthrosis; possibly requiring revision surgery with a nonunion repair of the osteotomy
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No 10-week postoperative CT scan to assess union of the fragment and osteotomy, which could lead to too early weightbearing and a higher risk of nonunion
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Infection, hematoma, thromboembolic events, wound healing problems, and transient or permanent nerve damage leading to hypaesthesia of the saphenous nerve, delayed or nonunion of the osteotomy or fixed fragment.