A new study published in the Journal of Bone and Joint Surgery examines the efficacy of patient specific instruments for total knee replacement.
The study authors conducted a meta-analysis based on studies in PubMed and Embase examining patient-specific instruments used in total knee replacement procedures from 2011 to 2015. There were 44 studies examined covering 2,866 patients who underwent surgery with patient-specific instrumentation and 2,956 patients who underwent knee surgery with standard instruments.
The researchers found:
1. Mechanical axis malalignment risks were lower for patients who underwent the procedure with patient specific instrumentation. The pooled relative risk was 0.79.
2. The patients who underwent surgery with patient specific instrumentation had a higher risk of tibial sagittal-plane malalignment than the patients who underwent the procedure with standard instrumentation.
3. The patient specific instrumentation was associated with lower risk of femoral coronal-plane malalignment except when using the fixed-effect meta-analysis.
4. The patients who underwent surgery with the patient specific instrumentation reported about 4.4 minutes shorter operative time and 37.9 mL less blood loss.
5. The researchers concluded the patient specific instrumentation improved accuracy for the femoral alignment as well as the global mechanical alignment. However, they experienced increased risk for tibial malalignment.
"The impact of the increased probability of tibial component malalignment on implant longevity remains to be determined," concluded the study authors. They reported the differences in the technology were minimal and "not a substantial justification for routine use of the technology."