Selective medial release using multiple needle puncturing with a spacer block in situ for correcting severe varus deformity during total knee arthroplasty.

INTRODUCTION: We aimed to establish a selective and sequential medial release technique using multiple needle puncturing (MNP) with a spacer block in situ in severe varus deformity during total knee arthroplasty (TKA) and to investigate its efficacy and safety.

MATERIALS AND METHODS: A total of 128 patients with a varus angle >15° were included. Patients were classified according to the tightness of extension and flexion (group 1, no tightness; group 2, extension; group 3, flexion; group 4, extension and flexion). When medial tightness was found on extension, the posterior clearing procedure, including release of the posterior capsule, posterior oblique ligament, and semimembranosus, was performed sequentially. When medial tightness was found on flexion, MNP using an 18-gauge needle with a spacer block in situ was performed at the anterior portion of the superficial MCL (aMCL). Clinical and radiological evaluations including stress radiographs were performed.

RESULTS: Among 128 knees, 110 required medial release (posterior clearing procedure only in 44 [34.3%], MNP with a spacer block in situ at aMCL only in 38 [29.7%], posterior clearing procedure and MNP in 28 [21.9%]). The mediolateral gap imbalances on extension and/or flexion were significantly improved (p < 0.001 in all). There were no significant differences in clinical radiological outcomes among groups. Over-release, iatrogenic transection, and postoperative laxity on the stress radiographs were not observed.

CONCLUSION: The selective and sequential technique using posterior clearing and/or MNP with a spacer block in situ can be a reliable option for managing medial tightness in severe varus deformity during primary TKA.