Stability and alignment do not improve by using patient-specific instrumentation in total knee arthroplasty: a...

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Reconstructive Surgery

Background:

• Total knee arthroplasty (TKA) aims to restore knee function and alignment.
• Patient-specific instrumentation (PSI) offers personalized surgical guides, potentially improving accuracy over conventional instrumentation (CI).
• Evaluating the comparative efficacy of PSI versus CI in TKA is crucial for optimizing surgical techniques and patient outcomes.

Purpose of the Study:

• To compare the stability and alignment of total knee arthroplasty (TKA) using patient-specific instrumentation (PSI) versus conventional instrumentation (CI) at 12 months postoperatively.
• To hypothesize that PSI would yield superior stability and alignment compared to CI.
• To assess and compare clinical outcomes between the two instrumentation methods in TKA patients.

Main Methods:

• A prospective randomized controlled trial involving 42 patients with knee osteoarthritis undergoing TKA with either PSI or CI.
• Stability assessed via varus-valgus laxity; alignment measured by hip-knee-ankle (HKA) angle and component rotation using radiographs and CT scans.
• Clinical outcomes including Knee Society Score, pain, satisfaction, and functional scores were evaluated at multiple postoperative time points.

Main Results:

• No significant differences were observed in stability, HKA alignment, or rotational alignment between the PSI and CI groups.
• Both groups demonstrated significant improvements in clinical outcomes over time, with no statistically significant differences at 12 months.
• The PSI group exhibited a smaller tibial slope and more frequent use of thinner insert sizes compared to the CI group.

Conclusions:

• Patient-specific instrumentation (PSI) does not offer significant advantages over conventional instrumentation (CI) in terms of postoperative stability and alignment in TKA.
• While PSI may allow for more conservative bone cuts, it required more frequent intraoperative ligament releases and did not result in superior clinical outcomes.
• Given comparable clinical results, higher costs, and increased time associated with PSI, conventional instrumentation (CI) is recommended for TKA.