Intraoperative repair for iatrogenic MCL tear due to medial pie-crusting in TKA yields satisfactory mid-term outcomes

Purpose

This study aimed to assess the rate of iatrogenic mid-substance superficial medial collateral ligament (sMCL) tear due to the medial pie-crusting technique during varus deformity total knee arthroplasty and compare the knee society score (KSS), range of motion (ROM), and instability rate of the repaired group to the control group with intact sMCL.

Methods

For this retrospective series of prospectively collected data, the multiple needle puncturing technique was performed for 653 out of the 1768 knees during algorithmic medial soft-tissue release. Iatrogenic tear was observed in 35 knees (5%); hence, repair with running locking nonabsorbable braided suture was performed. Patients were visited and reviewed both clinically and radiographically at 6 weeks, 3 months, 6 months, 12 months, and annually thereafter. Chi-square, ANOVA, Mann–Whitney, independent and paired t test were used to analyze the variables. P value < 0.05 was considered statistically significant.

Results

85% of the repaired sMCL had stable joints with a mean KSS of 88 ± 3 and a mean ROM of 103 ± 11 degrees (°). The other five patients (15%) with mean KSS of 40 ± 8 and mean ROM of 81° ± 5° had an instability and needed to undergo a revision surgery. The control group had a mean KSS of 86 ± 15 and mean ROM of 107° ± 8°; however, 7 knees had an instability and needed a revision surgery. No significant difference was observed in terms of KSS (P = 0.86) and ROM (P = 0.64) between the control and repaired groups.

Conclusion

The mid-substance sMCL tear is an important intraoperative complication of medial pie-crusting. Repairing this iatrogenic tear with nonabsorbable suture had satisfying clinical outcomes regarding the postoperative knee ROM and KSS in comparison to the control group. However, there is a chance of failure, which should be perceived by the surgeons.

Level of evidence

Therapeutic studies, investigating the results of treatment, Level III.