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Background: Patient-specific instrumentation (PSI) was developed to produce more accurate alignment of components and consequently improve clinical outcomes when used in total knee arthroplasty. We compare radiological accuracy and clinical outcomes at a minimum of 5-year follow-up between patients randomized to undergo total knee arthroplasty performed using PSI or traditional cutting block techniques.Methods: This multicenter, randomized control trial included patients blinded to the technique 1used. Outcome measures were coronal alignment measured radiologically, Euroqol-5D, Oxford knee score, and International Knee Society Score measured at 1- and 5-year follow-up.Results: At a minimum 5-year follow-up, there were 38 knees in the PSI group and 39 in the conventional instrumentation group for analysis. Baseline demographics and clinical outcome scores were matched between groups. Overall, there was no significant difference in the coronal femoral angle (P = .59), coronal tibial angle (P = .37), tibiofemoral angle (P = .99), sagittal femoral angle (P = .34), or the posterior tibia slope (P = .12) between knees implanted using PSI and those implanted with traditional cutting blocks. On the measurement of coronal alignment, intraobserver reliability tests demonstrated substantial agreement (k = 0.64). Clinical outcomes at both 1-year and 5-year follow-up demonstrated statistically significant and clinically relevant improvement in scores from baseline in both groups, but no difference could be detected between the Euroqol-5D (P = .78), Oxford knee score (P = .24), or International Knee Society Score (P = .86) between the 2 groups.Conclusion: This study has shown no additional benefit to PSI in terms of improved alignment or functional outcomes at minimum 5-year follow-up over traditional techniques. [ABSTRACT FROM AUTHOR]

Background: Patient-specific instrumentation (PSI) has been recently introduced in knee arthroplasty. There is no strong evidence from meta-analysis on comparison of functional outcomes between PSI and conventional instrumentation.Methods: Literature search of electronic databases PubMed, MEDLINE, and Cochrane Library for published randomized controlled trials was undertaken. Search was done using a predesigned search strategy. Eligible studies were critically appraised for the methodological quality using Cochrane Collaboration's tool. Functional scores used for meta-analysis were Knee Society Knee Score, Knee Society Function Scores, Oxford Knee Score, Western Ontario and McMaster Universities Arthritis Index, and Visual Analogue Scale score for pain (0-10 scale).Results: Five randomized controlled trials involving 379 total knee arthroplasties were eligible to be included in the meta-analysis. No significant improvement in short-term functional outcomes was seen after using PSI compared to the control group in terms of Knee Society Knee Score (weighted mean difference 0.65, 95% CI -4.41 to 5.70, P = .80) and Knee Society Function scores (weighted mean difference 0.01, 95% CI -3.26 to 3.28, P = .99), Oxford Knee Score (weighted mean difference 3.36, 95% CI -3.48 to 10.00, P = .34), Western Ontario and McMaster Universities Arthritis Index (weighted mean difference -7.47, 95% CI -23.94 to 8.99, P = .37), and Visual Analogue Scale score for pain (weighted mean difference -0.10, 95% CI -0.41 to 0.21, P = .53).Conslusion: Current literature is insufficient to address whether there is a benefit of PSI in total knee arthroplasty in terms of improvement in functional outcomes. [ABSTRACT FROM AUTHOR]

Patient-specific instrumentation (PSI) surgery may represent the next advancement in total knee arthroplasty (TKA). In 2011, 60 patients were prospectively recruited and divided into two groups based on the patient's choice: (1) PSI surgery; and (2) conventional TKA. At two years after surgery, the Knee Society Function Score, Oxford Knee Score and SF-36 scores were comparable between the two groups. Although the Knee Society Knee Score (KSKS) was 9 ± 3 points better in the PSI group (P=0.008), the two years improvement in KSKS was comparable between the two groups. None of the patients required revision surgery. These findings cannot justify the additional costs and waiting time incurred by the patients with PSI surgery in the practice of a high volume surgeon. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: Preoperative assessment of acetabular pathology, planning of bone preparation, and implant placement using current imaging, templating, and surgical techniques are imprecise, frequently resulting in component malposition. This study compared the accuracy of 2 surgical approaches: (1) standard preoperative imaging and instrumentation and (2) a novel 3-dimensional computed tomography scan–based preoperative planning software linked to patient- and implant-specific instrumentation (PSI) for placing acetabular components. The PSI group resulted in a significant improvement (P < .05) in the average deviation of implant position (actual vs planned) for version, inclination, and total offset. Fewer clinically relevant screw perforations were observed in the PSI group. This study shows proof of concept and justifies a clinical trial comparing PSI technology with standard surgical techniques. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Background: Proposed 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.Methods: One-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.Results: Sixty-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).Conclusion: PSI 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 Evidence: Level I, randomized, controlled trial. [ABSTRACT FROM AUTHOR]

Background There has been a recent interest in custom-made partial knee arthroplasties to provide patient-specific instrumentation and better fit of the prosthesis. While unicondylar knee arthroplasties (UKAs) have demonstrated good outcomes and durable results in many studies, there is little evidence on outcomes of these custom-made implants. Methods We performed a retrospective review of all custom-made UKAs performed at our institution by one surgeon from 2008 to 2015. We analyzed preoperative demographics, clinical follow-up evaluations, and radiographs and performed an analysis of risk factors including age, gender, height, weight, body mass index, and tibial insert thickness. The incidence of revision surgery, radiographic failures indicating component loosening, and symptomatic clinically failed implants was calculated at an average of 54.0 months of follow-up. Results We analyzed 115 consecutive custom-made medial UKAs from a single surgeon at our institution and found 29 (25.2%) UKAs had failed at an average of 33.1 months after surgery. Reasons for failure included aseptic femoral loosening (10), aseptic tibial loosening (8), loosening of both components (4), infection (3), progression of osteoarthritis (2), pain (1), and dislodged polyethylene insert (1). We found a significant relationship between implant failure and body mass index; no other study variables were statistically significant. Conclusion We found a relatively high rate of aseptic loosening and particularly femoral component loosening in the short- to intermediate-term follow-up period. While further study of larger numbers of custom-made UKA from multiple institutions may help verify these findings, we recommend careful consideration of the use of this implant. [ABSTRACT FROM AUTHOR]

Abstract: Osteopetrosis is an uncommon endocrine disease characterized by defective osteoclast resorption of bones. This causes a hard, sclerotic, and brittle bone throughout the skeleton. Fractures and unforgiving subchondral bone are common in this condition, both of which can lead to osteoarthritis. Total knee arthroplasty is often the treatment of choice but presents challenges due to the hard and sclerotic bone present throughout the metaphysis and diaphysis of the femur and the tibia. We present a case of knee osteoarthritis in a patient with osteopetrosis who underwent total knee arthroplasty using patient-specific instrumentation. This technique eliminates intramedullary alignment and minimizes drilling, reaming, and saw passes, making it attractive in the setting of diseases such as osteopetrosis to decrease operative time and potential complications. [Copyright &y& Elsevier]

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)., (Copyright © 2014 Elsevier Inc. All rights reserved.)

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., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The primary purpose of this prospective, randomized study was to determine if patient-specific instrumentation (PSI) for total knee arthroplasty (TKA) shortened surgical time. Secondarily the number of instrument trays and alignment were also compared to cases performed with traditional instrumentation (TI). Fifty-two cases (26 per group) were randomized and videotaped to measure the length of surgery, as well as each individual surgical step. Component alignment and mechanical axis was measured radiographically for each patient. Total surgical time was over 4 minutes shorter for patients in the TI group (57.4 minutes vs. 61.8 minutes; P<0.01). More instrument trays were used in the TI group (7.3 vs. 2.5; P<0.001). There was no significant difference in mechanical alignment between groups on postoperative long alignment radiographs (P=0.77). In conclusion, PSI did not shorten surgical time or improve alignment compared with TI in this prospective, randomized trial, but did reduce the required number of trays., (© 2013 Elsevier Inc. All rights reserved.)