Autologous osteoperiosteal transplantation for cystic osteochondral lesions of the talus: Bone reconstruction is essential.

PURPOSE: Autologous osteoperiosteal transplantation (AOPT) is one of the most feasible and effective techniques for cystic osteochondral lesions of the talus (OLT). However, few reports have been reported about the process of graft-host bone healing and bone articular surface reconstruction, which help us to further understand the actual situation of bone healing and modify surgical methods.

METHODS

The case series study retrospectively evaluated 33 osteochondral lesions in 30 patients undertaking AOPT for OLT with subchondral cysts from December 2016 to October 2021. According to CT observation, we used 4 variables to describe the bony articular repair, including the integration of the articular surface, the height of the bone filling, the status of bone union, and the appearance of bone resorption or cystic change. We also analyzed the demographic data and clinical function. Descriptive statistics were used for demographic and clinical variables. Normally distributed data were presented as mean ± SD, and non-normally distributed data were presented as median (Q1, Q3). Associations between these variables and the primary clinical outcomes were examined using t-test or one-way ANOVA test for continuous variables.

RESULTS

The patients' mean age was (41.7 ± 14.0) years old and the mean follow-up time was (29.6 ± 17.8) months. The chondral lesion size was (14.3 ± 4.1) mm. The cyst depth was (10.9 ± 3.7) mm. Significant improvements were observed in functional outcomes (according to the numeric rating scale for pain when walking and the American orthopedic foot and ankle society score) between the preoperative and latest follow-up evaluations, from 4.2 ± 2.1 to 2.2 ± 2.0 (p < 0.001), and from 66.8 ± 12.9 to 83.2 ± 10.4, respectively (p < 0.001). The overall satisfaction reached 8.3 of 10 points. All patients returned to sports and their median daily steps reached 8000 steps with 27 (81.8%) patients walking over 6000 steps daily. According to CT observation, "discontinuous bony articular surface and gap > 1 mm" was found in 27 grafts (81.8%), and "below the level of the adjacent articular surface, ≤ 1 mm" in a third of the grafts. Abnormal height of bone filling affected numeric rating scale score (p = 0.049) and American Orthopedic Foot and Ankle Society score (p = 0.027). Of note, bone resorption or cystic changes appeared in up to 13 autografts (39.4%).

CONCLUSIONS

AOPT is an effective and acceptable technique for cystic OLT. Bone reconstruction is essential for large cystic OLT. How to get better bony articular reconstruction and avoid cyst recurrence should still be paid more attention.