Does Patient-Specific Instrumentation Improve Femoral and Tibial Component Alignment in Total Knee Arthroplasty? A Prospective Randomized Study

Abstract

Alignment of the prosthesis is one of the most significant factors that affect the long-term clinical outcome following total knee arthroplasty (TKA). There is conflicting evidence whether patient-specific instrumentation (PSI) for TKA improves the component position compared to standard instrumentation. This study aimed to compare the rotational alignment of the femoral and tibial components in TKA patients when performed with either conventional or PSI. Sixty patients with primary knee osteoarthritis were randomly divided into two groups treated surgically with TKA: one with conventional instrumentation and the other with the Visionaire PSI system (Smith and Nephew, Memphis, TN). Computerized tomography (CT) and X-ray imaging were performed preoperatively and 12 weeks after surgery. The rotational alignment of the femoral and tibial component in all patients was assessed postsurgically using CT imaging according to the Berger protocol. Both groups were clinically assessed in a blinded fashion using the Knee Society Score (KSS) and a visual analog scale (VAS). Fifty-eight patients were prospectively assessed. The mean postsurgical follow-up was 3.0 ± 0.4 months. CT images did not reveal any significant improvement in the rotational alignment of the implant components between the groups. X-rays revealed a significant improvement in the deviation from the optimal alignment range of the femoral component in the coronal plane in both groups. Patients operated with Visionaire PSI assistance had poorer functional outcomes. We conclude that there were no improvements in clinical outcomes or knee component alignment in patients treated with PSI compared with those treated with standard instruments. In addition, clinical and functional assessment showed inferior results in terms of KSS and VAS scores at the midterm follow-up in patients treated with PSI.

Functional outcomes in patient specific instrumentation vs. conventional instrumentation for total knee arthroplasty; a systematic review and meta-analysis of prospective studies

“…The Knee Society Score was reported in 16 studies [ 19 – 29 , 31 , 34 , 35 , 37 , 38 ]. KSS Functional score was significantly higher in the PSI group (favouring PSI) at 24 months in the 5 studies compared (mean difference 4.36, 95% confidence interval 1.83–6.89), with moderate heterogeneity (I 2 = 66%) [ 19 , 20 , 22 , 26 , 31 ].…”

Higher Component Malposition Rates with Patient-Specific Cruciate Retaining TKA than Contemporary Posterior Stabilized TKA

“…However, PSI systems have not demonstrated improved accuracy when compared with manual instrumentation techniques in several published studies. [19][20][21][22][23][24] In another PSI-TKA study, the investigators reported a requirement for intraoperative modifications in the majority of cases with the use of a noncustomized implant design. 25 While manually instrumented TKA may accommodate intraoperative modification, it is not clear whether this would be either feasible or appropriate for a CIM-TKA placed using PSI technology.…”

Clinical and radiologic outcomes of two patellar resection techniques during total knee arthroplasty: a prospective randomized controlled study

“…In other studies, we have found that whether the patella is resurfaced in TKA has no significant differences in the KSS or the WOMAC score [2,30,31]. Other studies that examined the effects of using different surgical techniques as well as their use of various instruments and prostheses also reported that these factors had no relationship with these scores [32][33][34]. Therefore, we believe that better knee function may be more relevant to basic principles including excellent lower limb alignment, proper prothesis position, integrated ligaments, and greater lower limb strength.…”