Comparing conventional and patient specific instrumentation in total knee arthroplasty: an early analysis of function and satisfaction


  • Goncalo Vaz Pinto Unidade Local de Saúde do Litoral Alentejano, Santiago Do Cacém, Portugal
  • Sofia Caldeira-Dantas Dantas Unidade Local de Saúde do Litoral Alentejano, Santiago Do Cacém, Portugal
  • Tiago Bessa Magalhães Hospital Particular do Algarve - Gambelas, Faro, Portugal
  • Ana Paula Fontes Hospital Particular do Algarve - Gambelas, Faro, Portugal; Higher Health School, Algarve University
  • Ana Marreiros Faculty of Medicine and Biomedical Sciences, Algarve University; Algarve Biomedical Center, Algarve University
  • João Paulo Ribeiro De Sousa Hospital Particular do Algarve - Gambelas, Faro, Portugal



PSI, Total knee arthroplasty, Satisfaction, Function


Background: Patient specific instrumentation (PSI) in TKA is a surgical technique created to improve the accuracy of implantation, surgical time, blood loss and workflow that has been a growing trend over the past decade. Our work aims to determine if there are improvements in patient satisfaction and functional results using PSI in comparison with conventional instrumentation (CI) in TKA.

Methods: The authors evaluated 716 patients from the past 10 years that underwent TKA, either by PSI (n=456) or by CI (n=260). The authors recorded the WOMAC index, articular range of motion, and the six-minute walking test at pre-op and day 90 post-op. T-student and Mann-Whitney tests were used considering p<0.05.

Results: The functional scores achieved 90 days after surgery were better for PSI compared to CI. The respective differences are found in the extension (p=0.022), gait distance (p=0.010) and in the pain and function WOMAC index (respectively p=0.018 and p=0.020). No statistical differences were found in satisfaction.

Conclusions: 90 days after TKA, the functional scores achieved with PSI were better compared to CI. However, better results in this area did not translate to significantly higher satisfaction in the patients. There seems to be a tendency in favor of better functional results in patients that underwent TKA by PSI in comparison to those submitted to CI. These results seem to follow the tendencies demonstrated in available literature.


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Original Research Articles