Abstract
Background
Obtaining accurate alignment in total knee arthroplasty (TKA) remains a concern. Patient specific instrumentation (PSI) created using preoperative 3D modelling was developed to offer surgeons a simplified, reliable, efficient and customised TKA procedure.
Methods
In this prospective study, 60 patients who underwent TKA with conventional instrumentation and 71 patients operated on using PSI were followed for 1 year.(Table 1) The primary endpoint was surgical time. Secondary endpoints included the number of instrument trays used, radiographic limb alignment and clinical outcomes.
Results
Compared with conventional instrumentation, PSI significantly reduced total surgical time (mean, 8.9 minutes; ±3.3 minutes (standard deviation); p=0.038), OR time (8.6±4.2 minutes; p=0.043), and number of instrument trays (6 trays, p<0.001).(Table 2) Mechanical axis malalignment of the lower limb >3° was observed in 14% of PSI patients versus 29% with conventional instrumentation (p=0.043).(Figure 1) PSI predicted the size of the actual femoral and tibial components used in 85.9% and 78.9% of cases, respectively. There were no differences in VAS pain, EQ-5D and Oxford Knee Scores at 1-year follow-up.
Conclusion
PSI improves alignment, surgical and OR time over conventional instrumentation, reduces the number of instruments trays used and results in fewer outliers in overall mechanical alignment in the coronal plane. No advantages in terms of clinical outcome were noticed up to 1 year of follow-up.
