41 Fresh Allograft for Osteochondral Lesions of the Talus (OLT) Abstract Osteochondral lesions of the talus (OLT) are defects of the cartilage and subchondral bone often as a result of prior trauma. When painful, these can cause significant disability to the patient and considerably affect the patient’s quality of life. Here we discuss the use of fresh allograft to treat OLTs. This can be a powerful option to improve pain and maintain function of the ankle when used in the appropriate patient population. Keywords: osteochondral lesion, talus, fresh allograft • Indications for surgery. • Large osteochondral lesions of the talus (OLTs) with surface area >107 mm2 or any diameter >15 mm. • Deep OLTs with large cystic components. • Failed previous arthroscopic microfracture of OLT. • Failed previous autograft or allograft treatment for OLTs (osteochondral autologous transplantation surgery [OATS] or juvenile cartilage). • Lesion size too large for management with autograft harvest from patient’s knee. • Patient with a large OLT with severe knee arthritis or knee arthroplasty. • Patients unwilling to accept donor site morbidity associated with autograft. • OLTs are lesions of the articular cartilage and underlying subchondral bone that can be described based on location and size, whether they are stable or unstable, and whether they are displaced or nondisplaced.1,2 • They are found often after even minor trauma, occurring most frequently in patients previously sustaining ankle sprains.3 • The exact pathogenesis and cause of OLT is not quite understood to date, but acute trauma, repetitive microtrauma, systemic host factors, vascular abnormalities resulting in avascular necrosis, anatomic variation or malalignment, and congenital abnormalities are thought to play a role.1–3 • Inspection: look for signs of acute injury such as swelling or ecchymosis. • Palpation: evaluate for areas of focal tenderness. • Ligamentous exam: anterior drawer, inversion, and eversion stress test. • Hindfoot alignment exam with the patient standing and supine. • Evaluation for equinus contracture. • Evaluation for instability, malalignment, and contracture is especially critical, given that these should be corrected before or during allografting to prevent abnormal loading of the graft. • Radiographs in every patient—anteroposterior (AP), lateral, and mortise views with a radiographic marker to assist in future planning for graft size (Fig. 41.1). • Advanced imaging in select patients provides further detail for preoperative planning. These should be used with caution, however, as the OLT tends to appear less significant on CT and more exaggerated on MRI than it will appear in the operating room. • Asymptomatic lesions should be treated nonoperatively with serial radiographs. • Symptomatic, acute, and nondisplaced lesions should have a trial of nonoperative treatment with non–weight-bearing in a cast or boot. • Pediatric OLTs should be treated nonoperatively prior to surgical intervention. • Medical factors that would preclude any surgical intervention. • Any concern for infection. • Advanced arthritis of the ankle joint, as fresh allograft is unlikely to improve the patient’s condition in a significant and lasting manner. • Correctable alterations that place undue stress on the graft: • Relative contraindications: peripheral neuropathy and peripheral vascular disease. The goals of fresh allograft for OLTs include pain relief, ability to bear weight comfortably, and return to activity. One specific caveat, however, is, depending on the size of the allograft, return to running may not be a realistic goal. For example, if a hemitalus or whole talar dome is used, impact sports such as running may no longer be feasible. Fig. 41.1 Radiographs and magnetic resonance imaging of a 27-year-old woman with ankle pain and remote history of “ankle sprain” found to have an osteochondral lesion of the talus. Although many procedures are available for the management of OLTs, fresh osteochondral allografting is a powerful procedure in terms of pain relief and improvement in function. Fresh allograft provides viable cells, whereas the cartilage cells are dead in frozen allografts. Additionally, major advantages of fresh allografting over other treatments include avoidance of donor site morbidity and maintenance of ankle motion. The ability to use a whole talar dome allograft also allows for the repair of very large lesions. • Judicious preoperative planning including the following: • Adequate/appropriate exposure based on location of the defect. • Preparing the fresh allograft for the lesion. • Placement and fixation (if needed) of the allograft. • Prudent soft-tissue handling and closure of the wound. The correct allograft should be chosen based on radiographs performed with a size marker. Measure the talar width 5 mm below the articular surface on AP ankle radiograph. Correct for any magnification based on your radiopaque marker. This width can then be used to calculate the size of your OLT and size of proposed allograft (Fig. 41.2). Once the appropriate size is known, it is important to contact the chosen tissue bank to obtain the fresh allograft. Developing a relationship with a tissue bank is critical to understand the process for ordering and receiving the allograft. We have used Joint Restoration Foundation (Centennial, CO) in the past with good results. The allograft is procured from the donor within 24 hours of death and must be transplanted within 21 days of harvest. Donors are screened extensively, which requires approximately 2 weeks’ time. Grafts should be obtained from a bone bank certified by the American Association of Tissue Banks (AATB).
41.1 Indications
41.1.1 Pathology
41.1.2 Clinical Evaluation
41.1.3 Radiographic Evaluation
Computed tomography (CT) scan provides bony detail.
Magnetic resonance imaging (MRI) provides information about the cartilage and soft tissues (Fig. 41.1).
41.1.4 Nonoperative Options
41.1.5 Contraindications
Malalignment: angulation of the tibial plafond in any direction in relationship to axis of tibia greater 10 degrees may require corrective osteotomy.
Ankle instability.
Equinus contracture.
41.2 Goals of Surgical Procedure
41.3 Advantages of Surgical Procedure
41.4 Key Principles
Complete imaging of the lesion with size marker for templating.
Ensuring patient is an appropriate surgical candidate.
Obtaining the appropriate size-matched allograft.
Choosing an approach based on lesion location.
41.5 Preoperative Preparation and Patient Positioning
41.5.1 Choosing and Obtaining the Allograft
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