Current Data Do Not Support Routine Use of Patient-Specific Instrumentation in Total Knee Arthroplasty

The purpose of this systematic review and meta-analysis is to compare patient-specific instrumentation (PSI) versus standard instrumentation for total knee arthroplasty (TKA) with regard to coronal and sagittal alignment, operative time, intraoperative blood loss, and cost. A systematic query in search of relevant studies was performed, and the data published in these studies were extracted and aggregated. In regard to coronal alignment, PSI demonstrated improved accuracy in femorotibial angle (FTA) (P = 0.0003), while standard instrumentation demonstrated improved accuracy in hip-knee-ankle angle (HKA) (P = 0.02). Importantly, there were no differences between treatment groups in the percentages of FTA or HKA outliers (>3 degrees from target alignment) (P = 0.7). Sagittal alignment, operative time, intraoperative blood loss, and cost were also similar between groups (P > 0.1 for all comparisons).     

Patient-Specific Versus Conventional Instrumentation for Total Knee Arthroplasty: Peri-Operative and Cost Differences

The role of patient-specific instrumentation in total knee arthroplasty (TKA) is yet to be clearly defined. Current evidence evaluating peri-operative and cost differences against conventional TKA is unclear. We reviewed 356 TKAs between July 2008 and April 2013; 306 TKAs used patient-specific instrumentation while 50 had conventional instrumentation. The patient-specific instrumentation cohort averaged 20.4 min less surgical time (P < 0.01) and had a 42% decrease in operating room turnover time (P = 0.022). At our institution, the money saved through increased operating room efficiency offset the cost of the custom cutting blocks and pre-operative advanced imaging. Routine use of patient-specific TKA can be performed with less surgical time, no increase in peri-operative morbidity, and at no increased cost when compared to conventional TKA.     

Improved Radiographic Outcomes With Patient-Specific Total Knee Arthroplasty

Patient-specific guides can improve limb alignment and implant positioning in total knee arthroplasty, although not all studies have supported this benefit. We compared the radiographs of 100 consecutively-performed patient-specific total knees to a similar group that was implanted with conventional instruments instead. The patient-specific group showed more accurate reproduction of the theoretically ideal mechanical axis, with fewer outliers, but implant positioning was comparable between groups. Our odds ratio comparison showed that the patient-specific group was 1.8 times more likely to be within the desired + 3° from the neutral mechanical axis when compared to the standard control group. Our data suggest that reliable reproduction of the limb mechanical axis may accrue from patient-specific guides in total knee arthroplasty when compared to standard, intramedullary instrumentation.     

Patient-Specific Instrumentation in Total Knee Arthroplasty Provides No Improvement in Component Alignment

Improved component alignment in TKA remains a commonly cited benefit of MRI based patient-specific instrumentation (PSI). We hypothesized that PSI would lead to improved alignment versus traditional instrumentation (TI) during primary TKA. Fifty-eight knees (54 patients) that underwent TKA with PSI were compared to 62 knees that had previously undergone TKA with TI. Radiographs were evaluated for mechanical axis and alignment of the femoral and tibial components. Alignment was similar between the groups. However, the PSI group showed fewer knees in the target range for posterior tibial slope (PSI 38% vs. TI 61%, P = 0.01) in addition to a trend for fewer knees in target range for femoral flexion (PSI 40% vs. TI 56%, P = 0.07). This study demonstrated no improvement in overall alignment and perhaps a worsening of the tibial slope.     

Unsatisfactory Accuracy as Determined by Computer Navigation of VISIONAIRE Patient-Specific Instrumentation for Total Knee Arthroplasty

This investigation evaluated the Smith and Nephew VISIONAIRE patient-specific cutting block (PSCB) system for total knee arthroplasty. A consecutive series of 60 patients was recruited. Intraoperative computer navigation was used to evaluate the accuracy of the cutting blocks in the coronal and sagittal planes for the tibia, as well as rotational plane for the femur. The PSCB would have placed 79.3% of the sample within ± 3° of the preoperative plan in the coronal plane, while the rotational and sagittal alignment results within ± 3° were 77.2% and 54.5% respectively. The VISIONAIRE PSCB system achieved unacceptable accuracy when assessed by computer navigation. There might be many sources of error, but caution is recommended before using this system routinely without objective verification of alignment.     

A Randomized Trial Investigating the Cost-Utility of Patient-Specific Instrumentation in Total Knee Arthroplasty in an Obese Population

BackgroundPatient-specific instrumentation (PSI) has been introduced in total knee arthroplasty (TKA) with the goal of increased accuracy of component positioning by custom fitting cutting guides to the patient’s bony anatomy. A criticism of this technology is the associated cost. The purpose of this randomized controlled trial was to determine the cost-utility of PSI compared with standard of care (SOC) instrumentation for TKA in an obese population.MethodsPatients with body mass index greater than 30 with osteoarthritis and undergoing primary TKA were randomized to SOC or PSI. Patients completed a health care resource use diary and the EuroQol-5D at three, six, nine, and 12 months and the Western Ontario and McMaster Universities Osteoarthritis Index at three and 12 months postsurgery. We performed cost-utility and cost-effectiveness analyses from public health care payer and societal perspectives.ResultsOne hundred seventy-three patients were included in the analysis with 86 patients randomized to PSI and 87 to SOC. PSI was dominated (more costly and less effective) by SOC from a health care payer perspective. From a societal perspective, an incremental cost-utility ratio was calculated at $11,230.00 per quality-adjusted life year gained, which is cost-effective at a willingness to pay threshold of $50,000. Net benefit analyses found PSI was not significantly cost-effective at any willingness to pay value from either perspective.ConclusionOur results suggest that widespread adoption of PSI may not be economically attractive or clinically indicated. Future considerations are to compare long-term clinical outcomes and radiographic alignment between the groups.     

In-Vivo Alignment Comparing Patient Specific Instrumentation with both Conventional and Computer Assisted Surgery (CAS) Instrumentation in Total Knee Arthroplasty

Patient specific instrumentation (PSI) was developed to increase total knee arthroplasty (TKA) accuracy and efficiency. The study purpose was to compare immediate post-operative mechanical alignment, achieved using PSI, with conventional and computer assisted surgery (CAS) instruments in high volume TKA practices. This prospective, multicenter, non-randomized study accrued 66 TKA patients using PSI. A computed tomography (CT) based algorithm was used to develop the surgical plan. Sixty-two percent were females, 99% were diagnosed with osteoarthritis, average age at surgery was 66 years, and 33 was the average body mass index. A historical control group was utilized that underwent TKA using conventional instruments (n = 86) or CAS (n = 81), by the same set of surgeons. Postoperative mechanical alignment was comparable across the groups. Operative time mean and variance were significant.     

Comparison of Customized Cutting Block and Conventional Cutting Instrument in Total Knee Arthroplasty: A Randomized Controlled Trial

Background

Customized cutting block (CCB) was designed to ensure the accurate alignment of knee prostheses during total knee arthroplasty. Given the paucity of CCB efficacy data, we compare CCB with conventional cutting guide using a randomized controlled trial.

20-Year Minimum Outcomes and Survival Rate of High-Flexion Versus Standard Total Knee Arthroplasty

BackgroundThere are conflicting reports of early and mid-term results of the high-flexion total knee arthroplasties (TKAs). The purpose of the present long-term follow-up study was to determine the long-term (minimum 20 years) clinical and radiographic and CT scan results, and the survival rates of high-flexion versus standard TKAs.MethodsNinety-five patients (190 knees) were included (mean age, 65 ± 6.5 years). The mean follow-up was 20.3 years (range, 20 to 20.6 years).ResultsRevision of the TKA was performed in 5 knees (5.2%) with high-flexion TKA and in 3 knees (3.2%) with standard TKA. The rate of survival at 20 years was 94.8% (95% CI, 91%-98%) in the high-flexion TKA group and 96.8% (95% CI, 92%-100%) in the standard TKA group with reoperation for any reason. No knee had osteolysis in either group.ConclusionsAt this length of follow-up, high-flexion TKA has comparable outcomes and survivorship to standard TKA.     

Clinical Outcomes in High Flexion Total Knee Arthroplasty Were Not Superior to Standard Posterior Stabilized Total Knee Arthroplasty. A Multicenter,Prospective, Randomized Study

High flexion prostheses have been introduced to achieve high flexion and improve clinical outcomes. Controversy exists in the literature regarding outcomes of high flexion vs. standard implants. This multicenter study compares outcomes in patients receiving a high flexion prosthesis vs. standard prosthesis. 278 high flexion and standard knee prostheses were used. Patients were followed for two years and evaluated prospectively. The mean HSS was 87.3 for the standard group and 88.9 for the flexion group. At two-year follow up the standard prosthesis group had mean flexion of 121° and the high flexion group had mean flexion 120°. No knee had aseptic loosening, infection, or osteolysis. At two-year follow up, there were no significant differences in range of motion, clinical outcome, or radiographic evaluation. Pre-operative motion and functional status have greater impact on clinical outcome than implant alone.     

Patient-Specific Instrumentation Does Not Affect Rotational Alignment of the Femoral Component and Perioperative Blood Loss in Total Knee Arthroplasty: A Prospective,Randomized, Controlled Trial

BackgroundProposed aims of patient-specific instrumentation (PSI) for total knee arthroplasty (TKA) are to improve accuracy of component alignment, while reducing blood loss and surgical time. The primary goal of this prospective, randomized, controlled, clinical trial is to verify whether PSI improves the rotational alignment of the femoral component in comparison to conventionally implanted TKA.MethodsOne-hundred thirty-three consecutive patients were assessed for eligibility. Block randomization was performed to allocated patients in the treatment (PSI) or control group. During hospital stay, surgical times were recorded, and total blood volume loss and estimated red blood cell were calculated. Two months after surgery, a computed tomography of the knee was obtained to measure femoral component rotation to the transepicondylar axis and tibial component slope.ResultsSixty-nine patients were enrolled. PSI did neither result in a significant improvement in femoral component rotation nor result in a reduction of outliers, as compared with conventional instrumentation.No significant improvement in terms of tibial slope, blood loss, total surgical time, and ischemia time could be identified. The number of tibial recuts required in the PSI group was significantly higher than in the control group (P = .0003).ConclusionPSI does not improve the accuracy of femoral component rotation in TKA in comparison to conventional instrumentation. Moreover, PSI did not appear to influence any of the other variables investigated as secondary goals by this study. The results of this study do not support its routine use during standard TKA.Level of EvidenceLevel I, randomized, controlled trial.     

Long-Term Functional Outcomes and Quality of Life at Minimum 10-Year Follow-Up After Fixed-Bearing Unicompartmental Knee Arthroplasty and Total Knee Arthroplasty for Isolated Medial Compartment Osteoarthritis

BackgroundThe aim of this study is to compare the long-term functional outcome and quality of life between total knee arthroplasty (TKA) and fixed-bearing unicompartmental knee arthroplasty (UKA) for the treatment of isolated medial compartment osteoarthritis.MethodsBetween 2000 and 2008, a total of 218 patients underwent primary UKA at our tertiary hospital. A TKA group was matched through 1:1 propensity score matching and adjusted for age, gender, body mass index, preoperative knee flexion, and function scores. All patients had medial compartment osteoarthritis. The patients were assessed with the range of motion, Knee Society Knee Score and Knee Society Function Score, Oxford Knee Score, Short Form-36 physical component score (PCS) and mental component score preoperatively, at 6 months, 2 years, and 10 years. Patients’ satisfaction, expectation fulfillment, and minimal clinically important difference were analyzed.ResultsThere were no differences in baseline characteristics between groups after propensity score matching (P > .05). UKA had greater knee flexion at all time points. Although the Knee Society Function Score was superior in UKA by 5.5, 3, and 4.3 points at 6 months, 2 years, and 10 years, respectively (P < .001), these differences did not exceed the minimal clinically important difference (Knee Society Knee Score 6.1). There were no significant differences in the Oxford Knee Score and Short Form-36 physical component score/mental component score. At 10 years, similar proportions of UKA and TKA were satisfied (90.8% vs 89.9%, P = .44) and had expectation fulfillment (89.4% vs 88.5%, P = .46). Between 2 and 10 years, all function scores deteriorated significantly for both groups (P < .01).ConclusionUKA and TKA are excellent treatment modalities for isolated medial compartment osteoarthritis, with similar functional outcomes, quality of life, and satisfaction at 10 years.     

Total Knee Arthroplasty Using Bicruciate-Stabilized or Posterior-Stabilized Knee Implants Provided Comparable Outcomes at 2 Years: A Prospective,Multicenter, Randomized,Controlled, Clinical Trial of Patient Outcomes

Background

The bicruciate-stabilized (BCS) knee arthroplasty was developed to replicate normal knee kinematics. We examined the hypothesis that patients with osteoarthritis requiring total knee arthroplasty (TKA) will have better functional outcome and satisfaction with the BCS implant compared with an established posterior cruciate-stabilized implant.

No Major Functional Benefit After Bicompartmental Knee Arthroplasty Compared to Total Knee Arthroplasty at 5-Year Follow-Up

BackgroundIn case of isolated medial and patellofemoral joint arthritis, bicompartmental knee arthroplasty (BCA) is an alternative to total knee arthroplasty (TKA). The purpose of our prospective, randomized study is to compare the clinical outcome of BCA vs TKA.MethodsEighty patients with isolated medial and patellofemoral osteoarthritis were randomly assigned to either BCA or TKA. Patients were evaluated preoperatively, 3, 6, and 12 months, and 2 and 5 years after the procedure. Knee Society Score, Oxford Knee Score, and the University of California,Los Angeles activity scores were calculated at each follow-up; Forgotten Joint Score was assessed at final follow-up.ResultsThere was an improvement in Knee Society Score, Oxford Knee Score, and the University of California,Los Angeles scores in both groups but no significant differences between both groups at any follow-up. The Forgotten Joint Score at 5-year follow-up was not significantly different either. Range of motion was significantly greater in the BCA group from 1-year follow-up onward.ConclusionOur study did not show significant differences in clinical scores between BCA and TKA; only range of motion was significantly greater in BCA. Therefore, it is questionable whether this difference justifies the complexity of BCA associated with higher risk of failure. Maybe staged patellofemoral joint arthroplasty in the presence of a well-functioning UKA is an option for BCA and an alternative to revision to TKA. Long-term studies are needed to explore the potential benefits of BCA.     

Accelerometer-Based,Portable Navigation (KneeAlign) vs Conventional Instrumentation for Total Knee Arthroplasty: A Prospective Randomized Comparative Trial

Background

Accelerometer-based, portable navigation devices have been introduced as a less invasive and simpler technique to perform navigated surgical implantation of knee prostheses. They have been postulated to have better accuracy than conventional instruments in restoration of alignment in total knee arthroplasty.

A Prospective Randomized Controlled Trial Comparing Medial-Pivot versus Posterior-Stabilized Total Knee Arthroplasty

BackgroundThe medial-pivot (MP) design for total knee arthroplasty (TKA) aims to restore more natural “ball-and-socket” knee kinematics compared to the traditional posterior-stabilized (PS) implants for TKA. The objective of this study is to determine if there was any difference in functional outcomes between patients undergoing MP-TKA vs PS-TKA.MethodsThis prospective randomized controlled trial consisted of 43 patients undergoing MP-TKA vs 45 patients receiving a single-radius PS-TKA design. The primary outcome was postoperative range of motion (ROM). Secondary outcomes included the Western Ontario and McMaster Universities Arthritis Index, Oxford Knee Score, Knee Society Score (KSS), and radiological outcomes. All study patients were followed-up for 2 years after surgery.ResultsPatients undergoing MP-TKA had comparable ROM at 1 year (114.6° ± 16.3° vs 111.3° ± 17.8° respectively, P = .88) and 2 years after surgery (114.9° ± 15.5° vs 114.9° ± 16.4° respectively, P = .92) compared to PS-TKA. There were also no differences in Western Ontario and McMaster Universities Arthritis Index (26.8 ± 19.84 vs 22.0 ± 12.03 respectively, P = .14), Oxford Knee Score (42.7 ± 8.1 vs 42.3 ± 6.7 respectively, P = .18), KSS clinical scores (82.9 ± 16.96 vs 81.42 ± 10.45 respectively, P = .12) and KSS functional scores (76.2 ± 18.81 vs 73.93 ± 8.53 respectively, P = .62) at 2-year follow-up. There was no difference in postoperative limb alignment or complications.ConclusionThis study demonstrated excellent results in both the single-radius PS-TKA design and MP-TKA design. No differences were identified at 2-year follow-up with respect to postoperative ROM and patient-reported outcome measures.     

A Multi-Planar CT-Based Comparative Analysis of Patient-Specific Cutting Guides With Conventional Instrumentation in Total Knee Arthroplasty

Patient specific guides (PSGs) are postulated to improve the alignment of components in total knee arthroplasty. Three hundred consecutive total knee arthroplasties performed with either conventional (CON) (n = 185) or Visionaire PSG (n = 115) were evaluated with a CT protocol for coronal limb alignment, coronal and sagittal alignment of individual components and femoral component rotation. There was no statistically significant difference between the two groups in any of the above parameters. In addition, no difference was found in total operative time. PSGs do not offer any benefit over conventional guides in terms improving the coronal alignment of the limb or alignment of individual components.     

Innovative Devices Did Not Provide Superior Total Knee Arthroplasty Outcomes in Post-Operative Rehabilitation: Results From a Four-Arm Randomized Clinical Trial

BackgroundOrthopedic surgeons face an increasing array of post-TKA (total knee arthroplasty) rehabilitation interventions that entail innovative equipment and devices, but their relative effectiveness remains unknown. The study compared patient outcomes among primary unilateral TKA patients participating in one of 4 post-TKA rehabilitation interventions—a standard-of-care intervention and 3 more recently developed physical therapy interventions.MethodsThe Knee Arthroplasty Rehabilitation Outcomes Study is a 4-arm randomized clinical trial conducted across 15 outpatient rehabilitation clinics. The trial evaluated 4 alternative interventions: (1) a stationary recumbent bike (control intervention); (2) a body weight-adjustable treadmill; (3) a recumbent bike and use of a patterned electrical neuromuscular stimulation device; and (4) a body weight-adjustable treadmill and a patterned electrical neuromuscular stimulation device. The study’s outcome measures were patient walking speed and the Knee injury and Osteoarthritis Outcome Score (KOOS) measured at therapy discharge and at follow-up.ResultsThe study enrolled 363 TKA patients with 90-92 patients in each of the 4 study arms. Participants were similar across the 4 groups: They were about 63 years old, 61% female, 67% white, living at home, overweight (mean body mass index = 31.6), with mostly private insurance (61%) or Medicare (32%). Walking speed was similar at admission and discharge; KOOS scores were similar at admission, discharge, and follow-up across the 4 intervention groups.ConclusionThe study found no statistical or clinically meaningful differences across the 4 study arms in walking speed or KOOS outcomes. Clinicians, payers, and policy makers will want to encourage providers and patients to use the least expensive intervention since each provide similar outcomes.Trial RegistrationNCT02426190; https://clinicaltrials.gov/ct2/show/NCT02426190?term=NCT02426190&cntry=US&rank=1.