Addressing Osteochondral Lesions Of The Talus

Treating osteochondral lesions of the talus can pose challenges and delayed diagnosis due to late presentation after an ankle sprain. These authors evaluate the effectiveness of procedures such as microfracture and arthroscopy, and recent innovations such as juvenile particulate chondrocyte allografts.

Osteochondral lesions of the talus can be a difficult and frustrating pathology for foot and ankle surgeons to treat. The etiology of osteochondral lesions of the talus is frequently attributed to ankle trauma but these lesions can also stem from alcohol abuse, chronic steroid use, endocrine abnormalities or genetics.^1,2 Researchers have reported an occurrence of up to an astounding 73 percent in ankle fracture cases and 42 percent in people with lateral ankle instability.³

The high incidence of osteochondral lesions of the talus in primary ankle trauma is unfortunate as delayed diagnosis typically occurs as a result. Loomer and colleagues reported a delayed diagnosis of osteochondral lesions of the talus after injury of up to two years.⁴ Early diagnosis is essential and has been linked to better patient outcomes.⁵

Classically, the typical patient with an osteochondral lesion of the talus presents clinically with low-grade aching ankle pain months after an ankle sprain. The patient may describe a deep or aching pain with occasional instability, catching or locking. A reduced or painful range of motion, mild non-pitting edema and medial or lateral tenderness to palpation may be evident on a physical exam.
Roentgenograms are largely insufficient for definitive diagnosis and contribute to the high incidence of delayed diagnosis. Magnetic resonance imaging (MRI) is the gold standard for evaluating osteochondral lesions and one should order this for chronic ankle pain unresponsive to nonsurgical care. The use of MRI enables one to evaluate the tibiotalar joint for synovitis, stress reaction, avascular necrosis, chondritis and osteoarthritis in addition to osteochondral lesions. Recently, Kok and coworkers discussed the role of ultrasonography in diagnosing osteochondral talar lesions.⁶

One may initiate treatment for osteochondral lesions of the talus by nonsurgical means. These options include non-weightbearing for six to eight weeks, immobilization, corticosteroid injection and physiotherapy. Extracorporeal shockwave therapy has recently emerged in the discussion for treatment of early lesions with promising initial results.³ While one should consider nonsurgical treatment initially, keep in mind that nonsurgical management of osteochondral lesions of the talus is only reportedly successful in 25 to 45 percent of cases.^7,8

Arthroscopy is an important component of treating recalcitrant osteochondral lesions of the talus. This allows direct visualization of the articular cartilage of the talar dome without the potential complications of an open arthrotomy. Pritsch and coworkers showed a correlation between an intraoperative classification system of osteochondral lesions of the talus and patient outcomes.⁹ Ferkel and colleagues also found a significant correlation between their intraoperative grading system and clinical outcomes.¹⁰ Surprisingly, they also reported no correlation between clinical outcomes and classification grade via radiograph, MRI or computed tomography (CT).

Debridement with microfracture has proven to be an effective treatment in addition to diagnostic arthroscopy for patients with small osteochondral lesions of the talus. Surgeons can remove loose fragments and perform microfracture with an awl for bone marrow stimulation. Fibrocartilage (type I collagen), not hyaline cartilage (type II collagen), forms as a result of the bone marrow stimulation.

The literature shows the progression of better patient outcomes initially for microfracture but poorer outcomes during long-term follow up. Hunt and Sherman found 54 percent of patients had fair or poor outcomes after arthroscopy and microfracture at 66 weeks.¹¹ However, Ferkel and coworkers reported good to excellent results in 72 percent of patients who had microfracture after a mean 71 months.¹⁰

In the literature review by Zengerink and colleagues, fragment excision alone had a 54 percent success rate, excision and curettage had a 77 percent success rate, and excision with bone marrow stimulation had an 85 percent success rate.¹² In a recent study, Goh and colleagues assessed the combination of arthroscopic chondroplasty, removal of loose bodies and microfracture in 61 patients with osteochondritis dissecans of the talus.¹³ They observed significantly improved Visual Analogue Scale (VAS) and Short Form-36 scores at the 12-month follow-up.¹³ They reported improved short-term functional outcomes as well.

Pertinent Pointers On The Utility Of Retrograde Drilling

Retrograde drilling is an excellent treatment option for osteochondral lesions of the talus with intact overlying cartilage. Although short-term results are adequate for treatment with antegrade drilling or transmalleolar drilling, long-term outcomes are poor.¹⁴ Also, there are instances in which an osteochondral lesion may be unreachable via the typical arthroscopic portals. During retrograde drilling, the trauma triggers an inflammatory response to stimulate new bone formation in the area of the lesion while not encroaching on the intact, healthy cartilage. One removes necrotic bone and creates vascular access channels, allowing an ideal environment for chondral reattachment.

Success is reportedly up to 100 percent for retrograde drilling in smaller osteochondral lesions of the talus.¹⁵ Hyer and coworkers observed a mean American Orthopaedic Foot and Ankle (AOFAS) hindfoot score improvement of 34 points in a case series of patients who had retrograde drilling.¹⁴ Kono and colleagues compared outcomes in retrograde drilling of osteochondral lesions versus transmalleolar drilling.¹⁵ The osteochondral talar lesions that were treated with retrograde drilling remained more stable than lesions treated with transmalleolar drilling at the one-year follow-up. Surgeons perform transmalleolar or antegrade drilling through the malleolus into the cartilage and subchondral bone. Success rates for this technique are reportedly around a meager 60 percent, likely due to the violation of healthy, native cartilage.¹⁶

What Are The Potentially Viable Alternatives To Tibiotalar Joint Arthroscopy?

Occasionally, tibiotalar joint arthroscopy is insufficient to address large osteochondral lesions of the talus. It has been well-reported that lesions greater than 1.5 cm in diameter are at higher risk for healing complication and do not respond well to arthroscopic treatment with microfracture alone.¹⁷ Recurrent lesions may also be inappropriate for arthroscopy.

Additionally, capsular adhesions, osteophytosis, arthrofibrosis or anatomical constraints can limit the effectiveness of arthroscopy. In these cases, consider open arthrotomy or malleolar takedown. These procedures have been associated with higher complication rates and patient morbidity.¹⁷ Despite this, both open arthrotomies and malleolar takedowns provide the surgeon with excellent visualization and exposure to treat larger osteochondral lesions of the talus. Siegel and Mount reviewed the different types of medial malleolar takedowns.³ They recommended a step-cut osteotomy with a right-angle intersecting osteotomy 1.5 cm above the superomedial gutter due to its biomechanically sound nature and resistance to rotational malunion.

An alternative to the malleolar takedown is the use of a trephine with a micro vector drill guide. The surgeon is able to core out a tunnel with the use of a trephine in order to better access the talus. This will allow him or her to visualize and perform debridement or transplant, then reinsert the malleolar plug and suture the periosteum for fixation.¹⁸

Key Insights On Autologous Chondrocyte Implantation And Osteochondral Autograft Transfers

Physicians can use autologous chondrocyte implantation for larger lesions but it is expensive and requires two separate operations: the initial procedure to harvest the chondrocyte cells and the second surgery to harvest periosteum for the tibia to implant on the area of the lesion with fibrin glue. Then one would inject the chondrocytes underneath the periosteal patch in the talus where the hyaline cartilage will theoretically reconstitute. Whittaker and colleagues reported a 90 percent patient satisfaction rate at four years with this procedure.¹⁹

With osteochondral autograft transfers (OATS), one harvests a hyaline cartilage plug from the anterior, non-weightbearing surface of the distal femur. The surgeon then transfers this graft to the affected area on the talus in order to maintain a complete articular surface of native hyaline cartilage. Good to excellent outcomes occurred in 90 to 94 percent of patients who had osteochondral autograft transfers in one study.⁷ These techniques have a significant advantage over microfracture and bone marrow stimulation as they preserve the hyaline cartilage nature of the articular surface of the talar dome. Fibrocartilage does not handle wear as well as hyaline cartilage, which likely results in an earlier failure of the graft.⁷

While these techniques have high success rates, they do have disadvantages. Osteochondral autograft transfers require the harvest of a graft from the knee, which results in inevitable donor site morbidity. Autologous chondrocyte implantation is expensive as clinicians must harvest the chondrocytes and grow them in the laboratory, and it requires two separate visits to the operating room. One must consider these factors during the surgical consultation.

What You Should Know About Juvenile Particulate Chondrocyte Allograft

Recently, juvenile particulate chondrocyte allograft has been in use for cartilage repair of osteochondral lesions of the talus. This is a prepackaged allograft substance consisting of immature live chondrocyte cells within their native extracellular matrix from donors typically under the age of 13.²⁰

With juvenile particulate chondrocyte allograft, there is a much higher cell density, cell proliferation rate, cell outgrowth and glycosaminoglycan content than mature articular cartilage.²¹ This negates the need for autologous harvest and multiple surgeries while supplying the surgeon with viable juvenile chondrocytes that are readily available. Cost is also significantly lower than the cost for the two surgeries that would be necessary with autologous chondrocyte implantation and a fresh talar allograft. With this technique, only fibrin glue is required for stabilization of the allograft and no other biological dressing is necessary.

There have been excellent short-term outcomes for this modality in the knee but the use of juvenile particulate chondrocyte allograft in the ankle is not as well studied. A systematic review of the use of juvenile particulate chondrocyte allograft for osteochondral lesions of the talus showed very positive short-term results.²⁰ Patient-reported outcomes were excellent as 100 percent of patients said they would have the procedure again. Additionally, 83.9 percent of patients reported extreme subjective pain improvement. Only one case had to be revised.

Looze and colleagues also looked at a cohort of six patients who received juvenile particulate chondrocyte allograft.²² All patients reported reduced pain, improved range of motion and improved functionality at the final follow-up. Keep in mind that the average follow-up time for the cases included in the systematic review was 14 months. Short-term results for this method of treating osteochondral lesions of the talus are promising in regard to patient-reported outcomes and cartilage regeneration.

Do Talar Allografts Have Potential?  

Autologous grafts from the talus have shown success in recent years. This graft originates from the anterior aspect of the ipsilateral talar dome and surgeons transfer it to the affected portion of the talus. Georgiannos and coworkers’ midterm results with 46 patients showed a 35 point increase in the American Orthopedic Foot and Ankle (AOFAS) score at the five-year follow-up.²³ No nonunions or donor site morbidity occurred.

Fresh bulk allograft transplantations are an alternative option for large or recurrent osteochondral lesions of the talus if subchondral bone is violated. Although malleolar takedowns are often necessary, cadaveric talus provides advantages over surgical treatment via arthroscopic means. With an entire talus to work with, the surgeon is able to shape the transplant exactly as he or she wishes to ensure an adequate conformation with the patient’s native talus. Additionally, there is no associated donor site morbidity, and incorporation rates are reportedly similar to those of autogenous grafts.²³

Ahmad and Jones compared osteochondral autograft versus allograft for recurrent osteochondral lesions of the talus in a prospective, randomized trial.²⁴ Their results showed no significant difference in the Foot and Ankle Ability Measure, VAS scores or nonunion rates between groups after a mean follow-up of 35 months. A systematic review of fresh bulk allograft transplantations for osteochondral lesions of the talus showed AOFAS scores increased 67 percent and VAS scores decreased 62 percent over a mean 45-month follow-up.²⁵ Unfortunately, these promising results were also associated with a 13 percent failure rate, 22 percent complication rate and a 25 percent reoperation rate.

Orr and coworkers found that while fresh bulk allograft transplantation is an excellent surgical option for middle-age patients, failure was higher in a younger population with greater physical demands.²⁶ Despite this, fresh bulk allograft transplantation continues to be a viable alternative for patients with large osteochondral lesions of the talus who have failed an initial operation but are resistant to an ankle joint arthrodesis or arthroplasty. Composite bone graft substitutes have been in use for transplantation as well but have shown inferior results to autogenous grafts.²⁷

Case Study: A Closer Look At Retrograde Drilling For Osteochondritis Dissecans

A 55-year-old female presented to our office in April 2013 with complaints of severe ankle pain that were unresponsive to previous treatment consisting of bracing, nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroid injections and physical therapy. This pain had been present for four years and had worsened the past two years. She had a history of a severe ankle sprain one year ago. The use of a brace and physical therapy resolved the sprain.

X-rays demonstrated osteochondritis dissecans and MRI revealed a defect with intact cartilage perfect for retrograde drilling. We performed retrograde drilling using arthroscopic guidance in July 2013.
Postoperatively, the patient did well and was walking without pain from the 16th week onward. She continues to walk pain-free three years later and is currently walking three miles per day.

In Conclusion

Curettage with microfracture continues to be a first-line treatment for naive osteochondral lesions of the talus less than 1.5 cm in diameter. One should perform retrograde drilling for patients with intact cartilage. When treating larger lesions, the utilization of fresh bulk allografts or autologous grafts from the talus may be necessary. Future studies would ideally include both functional and patient-reported outcomes to elucidate the true success of surgical management of osteochondral lesions of the talus.

Dr. Grady is the Director of the Foot and Ankle Institute of Illinois, and the Director of the Foot and Ankle Institute for Research in Oak Lawn, Ill. He is also the Director of the Jesse Brown Veterans Affairs Medical Center Residency Program in Chicago. Dr. Grady is a Fellow of the American Society of Podiatric Surgeons.

Dr. Sanchez is a third-year resident at Jesse Brown Veterans Affairs Medical Center in Chicago.

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