By Jennie McKee

Studies explore how much defect size should affect treatment of OLT

Osteochondral lesions of the talus (OLT) commonly affect young, athletic people (Fig. 1). It’s unclear, however, how great an impact defect size should have on the treatment algorithm.

According to two separate studies presented at the American Orthopaedic Foot and Ankle Society’s (AOFAS) 24th annual summer meeting, lesion size is one of the most important factors to consider in devising a treatment plan.

The larger the lesion, the worse the outcome
Both studies sought to determine a treatment modality for OLT by analyzing the effects of different prognostic factors, with an emphasis on lesion size.

In a study performed at Yonsei University College of Medicine in Seoul, South Korea, Woo Jin Choi, MD, and colleagues evaluated 117 patients (120 ankles) who underwent arthroscopic treatment for OLT from January 2001 through June 2006. Mean patient age was 34.6 years old (range: 13 to 66 years old), and mean follow-up was 44.5 months (range: 12 to 81 months). The AOFAS ankle-hindfoot scale was used to assess clinical results; magnetic resonance imaging (MRI) was used to assess lesion size and location.

Surgeons treated 64 ankles with microfracture surgery and 56 ankles with chondroplasty. Treatment was deemed a clinical failure if the patient had osteochondral transplantation after arthroscopic surgery or an AOFAS score of less than 80 points. The overall failure rate was 25 percent (30 ankles).

No correlation was found between outcome and patient age, duration of symptoms, history of trauma, or associated lesions (p>0.05). Notably, statistical analysis showed a significant inverse relationship between the size of the lesions and the AOFAS score (r = –0.843; p<0.001). statistically significant chang­es in the aofas score occurred with lesions larger than 150 mm2 (p><0.001).>

Retrospective review finds similar results
W. Bret Smith, DO, presented the results of a retrospective review of 189 patients who underwent surgical treatment for OLT at the Orthopaedic Foot and Ankle Center in Columbus, Ohio. He agreed with Dr. Choi regarding the crucial role that lesion size plays in predicting long-term surgical outcomes.

In his study, which had a mean follow-up time of 37 months, researchers evaluated the efficacy of initial surgical treatment and completed clinical and radiographic reviews of patients with OLT. Researchers used patient surveys to gather information on patient age, lesion size and location, type of lesion (cystic or non-cystic), initial procedure performed, any repeat procedure performed, and any complications. They also evaluated final outcome and return to activity.

“We analyzed the results of the patient surveys and correlated them with the size of the lesions,” explained Dr. Smith. “The average lesion sizes for patients whose outcomes were rated ‘good’ or ‘fair’ were 67.08 mm² and 76.26 mm², respectively. Patients who had poorer outcomes had larger lesions, averaging 109.14 mm².”

According to Dr. Smith, most patients who underwent arthroscopic drilling of their osteochondral lesion improved.

“Two parameters showed significant differences in outcome: size of the lesion (greater than or less than 1 cm²) and presence of cystic or noncystic changes,” said Dr. Smith.

The study also evaluated length of time from injury to diagnosis and treatment.

“Greater length of time between injury and treatment correlated with lower outcome scores,” said Dr. Smith.

Figuring lesion size into the treatment plan
According to Dr. Choi, because defect size has a significant influence on clinical outcomes, surgeons should perform MRI to determine defect size before choosing a surgical procedure.

“Arthroscopic treatment should be used for lesions less than 150 mm²,” said Dr. Choi. “For larger lesions, it is reasonable to consider osteochondral transplantation as a primary treatment modality.”

Dr. Smith noted that his study also found a direct correlation between the size of the lesion and surgical outcomes.

“Arthroscopic drilling of OLT is an efficacious treatment option for the correct patient population. Lesions larger than 100 mm² and cystic lesions are often associated with inferior functional outcomes and may require a more extensive initial procedure,” said Dr. Smith. “Judicious screening of the patient population will increase patient satisfaction and improve outcomes.”

Dr. Choi was the presenter and lead author of the study, “Correlation of Defect Size and Clinical Outcome in Osteochondral Lesions of the Talus.” Co-authors included Jin Woo Lee, MD, PhD; Bom Soo Kim, MD; and Seung Hwan Han, MD.

Dr. Smith was the presenter and lead author of the study, “Osteochondral lesions in the talus: Predictors of outcome and treatment algorithm.” Co-authors included Daniel Cuttica, DO; Christopher F. Hyer, DPM; William T. DeCarbo, DPM; Terrence M. Philbin, DO; Thomas H. Lee, MD; and Gregory C. Berlet, MD.

Jennie McKee is a staff writer for AAOS Now. She can be reached at mckee@aaos.org

Drs. Smith, Cuttica, and DeCarbo have nothing to disclose. Dr. Hyer reported ties to Biomet, DJ Orthopaedics, Wright Medical, and Bledsoe Corporation. Dr. Philbin reported ties to Arthrocare, Biomet, DJ Orthopaedics, Pegasus, Pfizer, and OrthoHelix. Dr. Lee reported ties to Arthrex, DJ Orthopaedics, EBI, Zimmer, Wright Medical Technology, Inc., and DePuy. Dr. Berlet reported ties to DJ Orthopaedics; Wright Medical Technology, Inc.; Biomet; Arthrex, Inc.; Darco; Pegasus; Pfizer; and Tornier. Dr. Choi and his co-authors report no conflicts.