Abstract
Background
A grossly deformed knee is believed to be an indication for PS -TKA. However, the role CR-TKA in such knees is unclear in the literature. Considering the obvious advantages of CR, we analysed the mid term follow up of CR knees in gross deformities.
Materials and Methods
1590 patients (1740 knees) underwent TKA between January 2011 to December 2012, out of which 570 knees had gross deformity (varus > 15°, FFD > 10°, valgus > 10°, recurvatum > 10). CR-TKA was performed for 540 knees and were included in our study. Subvastus approach was used for all knees. Average age being 68 years, mean BMI being 32 and average weight 70 kgs. Intraoperatively, POLO test was used to ensure PCL stability, further confirmed by direct palpation. Femoral roll-back was found adequate.
Results
95% of grossly deformed knees underwent CR-TKA. Mean pre-operative knee score was 45 which improved to 94 at mid-term follow-up at 18 to 36 months. There were no incidence of component loosening or instability. Three knees needed secondary resurfacing of patella. One knee got infected for which components were explanted and joint debrided thoroughly. Lateral radiographs showed consistent roll-back in all except for 3 knees which had femoral roll-forward.
Discussion
PS-TKA have shown to yeild good results in gross deformities, however the role of CR had been unclear. Contrary to popular belief, in our opinion, greater the deformity, greater is the need to retain the PCL. Balancing the flexion extention space is easier and involves lesser resection of distal femur. Hence, its bone preserving. For valgus knees, PCL acts a medial stabilizer. In recurvatum deformity, the posterior capsule being stretched out, retaining PCL has prime importance. Our retrospective mid term follow up have shown good results. However, long term analysis is necessary to highlight the survivorship.
Conclusion
CR-TKA must be considered for knees with gross deformity for its aforementioned advantages.
