Historically, terms including osteochondritis dessicans, transchondral talus fracture, and osteochondral talus fracture have been used to describe what are now referred to as osteochondral lesions of the talus (OLTs). OLTs form a subset of osteochondral lesions that occur in various typical areas of the skeleton. While most lesions are unilateral, patients do have bilateral lesions. The lesions usually occur in two areas of the dome of the talus. Medial osteochondral lesions are more common than lateral osteochondral lesions. Medial lesions have been described as deeper, extending into subchondral bone and often developing into cystic lesions. Lateral lesions are more commonly associated with a traumatic injury and are described as shallow, with a greater tendency to become displaced.

The etiology of an OLT can be divided into nontraumatic and traumatic defects. Most authors believe that a traumatic etiology has an integral role in the pathogenesis of a vast majority of OLTs. It is hypothesized that they represent the chronic phase of a talar dome compression fracture. A single event of macrotrauma or repetitive microtrauma may initiate the lesion in an individual already predisposed to talar dome ischemia. The development of a symptomatic OLT depends on various factors. The primary mechanism is damage and insufficient repair of the subchondral bone plate.

The diagnosis of an OLT is rarely made immediately after an acute ankle injury. In most cases, it is associated with chronic ankle pain that develops after a traumatic incident, commonly an inversion injury to the lateral ligamentous complex. Patients presenting with an OLT often describe prolonged pain, recurrent ankle swelling, weakness, and subjective instability. The pain is commonly described as deep in the ankle. Patients may also report mechanical symptoms, including catching, clicking, and locking. The physical examination often reveals tenderness at the level of the ankle mortise anteriorly or posteriorly. Ligamentous insufficiency or laxity may be present and should always be evaluated, as it will help guide potential treatment. The examination, however, may be benign; thus, the history is usually the best way to assess for the possibility of an OLT. A high index of suspicion for an OLT must be maintained when evaluating patients with chronic ankle pain.

Advanced imaging modalities have significantly increased our ability to accurately diagnose OLTs. CT is predominantly utilized as an adjunct for a more comprehensive evaluation and preoperative planning of known lesions. MRI is the preferred imaging study for detection of a suspected OLT that is not seen on initial plain radiographs (Figure 57.1). It is also extremely useful for further evaluation and staging of a known OLT. MRI provides improved three-dimensional localization and sizing of the lesion. It also aids in the assessment of stability and determination of the presence of a cystic component.

A trial of nonoperative management for OLTs is appropriate for nondisplaced lesions. While several authors recommend a 3-month period of conservative treatment, there remains no clear consensus on the ideal regimen. Nonoperative treatment ranges from non–weight bearing in a cast to protected weight bearing in a boot.

Nonoperative treatment should include a course of physical therapy following immobilization. The active treatment progression may follow a very similar course as the postoperative regimen, although the speed of progression will be
based primarily on patient symptoms and response rather than time. Most patients will also benefit from manual therapy. Components of manual therapy include joint mobilizations to distract the talus, which allows for better anterior-posterior or medial-lateral alignment. Soft-tissue release to the peroneals, gastrocnemius-soleus complex, and anterior compartment may allow for decompression of the joint that occurs due to compensatory overuse of the lower leg musculature.

Surgical intervention is indicated for acute displaced osteochondral lesions and for those lesions refractory to conservative care. The surgical approach and objectives of surgery are variable and dictated by the type of lesion. Furthermore, patient-specific goals must be strongly considered prior to proceeding with surgical management. Goals may include removal of a loose fragment or securing a larger fragment anatomically. However, the primary objective is to create an environment for functional fibrocartilaginous proliferation or resurfacing with hyaline cartilage to restore more normal joint function.

The primary traditional approach includes open-ankle arthrotomy. Numerous exposure methods have been described, including several variations of medial malleolar osteotomies, distal tibial osteotomies, along with combined anterior and posterior arthrotomies. Open approaches involve significant tissue trauma and, as a result, may be associated with postoperative stiffness, prolonged rehabilitation time, and poor cosmetic appearance.

Ankle arthroscopy has established itself as a useful tool in both the diagnosis and treatment of osteochondral lesions of the talus. Compared to an extensive open approach, arthroscopy has proven to provide superior visualization of the talar dome along with improved access to the lesion. As a result of recent advances, arthroscopic management of osteochondral lesions of the talus is now the preferred technique whenever possible.

A wide variety of procedures that vary in complexity have been described for the treatment of OLTs. Treatment strategies generally are categorized as primary repair, reparative techniques, or restorative techniques. Primary repair techniques involve stabilizing large, acute, displaced fragments with commercially available metal or bioabsorbable implants. Reparative treatments are marrow-stimulation techniques, which include abrasion arthroplasty, microfracture, and drilling techniques. On occasion, these techniques may require bone grafting of the defect, then marrow stimulations techniques later. The goal of these various techniques is to stimulate fibrocartilaginous proliferation to resurface the talus. Restorative techniques primarily include autologous chondrocyte implantation (ACI), osteochondral autologous transfer system (OATS and mosaicplasty) and fresh osteochondral allograft. The primary goal of these techniques is resurfacing with hyaline cartilage. ACI is a two-stage operation. The first step involves harvesting of the patient’s own chrondrocytes, which are then cultured and grown in a laboratory and followed by a surgical procedure for implantation of the chondrocyte suspension beneath a sutured periosteal flap. The OATS is a single stage procedure that involves harvesting an osteoarticular plug, typically from the ipsilateral knee, and implanting it into the talus in a press-fit technique. Mosaicplasty is a term that describes harvesting and transfer of multiple smaller osteoarticular plugs to fill a single large void. Osteochondral allograft involves harvesting a sized matched portion of a fresh cadaveric talus that is often secured to the native talus via screws but may also
be implanted in an OATS-type fashion. Future directions in restorative techniques for OLTs include matrix/membrane ACI (MACI), collagen-covered autologous chondrocyte implantation (CACI), arthroscopic allograft/autograft (AAP) with platelet-rich plasma (PRP) implantation, stem cell–mediated cartilage implants, and other scaffolds.

When selecting the appropriate treatment option, there are several important variables to consider. It is imperative to delineate—primarily from advanced imaging (MRI and/or CT)—the type, stability, and displacement of the lesion. Chronicity, size, location, and containment are other important factors to consider. Reparative treatments generally are indicated for lesions that do not involve the extreme medial or lateral margins of the talus and are less than 1.5 cm² in size. These techniques are relatively inexpensive, with low morbidity and a high success rate. Restorative techniques are considered for larger and deeper lesions that are not amenable to the reparative techniques previously described.

Due largely to insufficient research, no true consensus exists regarding a formal rehabilitation program and return to sport times after surgical treatment of OLTs. Furthermore, a vast array of literature with high variability in surgical techniques and postoperative treatment protocols limits any definitive conclusions.

Since arthroscopic treatment is the most common surgical intervention, our postoperative rehabilitation protocol is primarily aimed at treatment after excision, curettage of the OLT, and subsequent bone marrow stimulation. Variations of this protocol exist and are dependent primarily on the type, size, and location of the lesion. Often, a more conservative approach is deemed necessary if restorative techniques are utilized to allow time for bone healing.

The general trend of postoperative rehabilitation in recent years has been to move away from “time-based” protocols to more functional or “criteria-based” protocols. This allows each program to be tailored to the deficits and weaknesses of each patient, as well as to their sport-specific goals. Our protocol consists primarily of time-based phases early, with the primary goal of ensuring bone and cartilage healing and patient symptom control. As the patient progresses and healing has taken place, we transition to functional criteria for progression.