Aims. Neither a surgeon’s intraoperative impression nor the parameters of computer navigation have been shown to be predictive of the outcomes following total knee arthroplasty (TKA). The aim of this study was to determine whether a surgeon, with robotic assistance, can predict the outcome as assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) for pain (KPS), one year postoperatively, and establish what factors correlate with poor KOOS scores in a well-aligned and balanced TKA. Methods. A total of 134 consecutive patients who underwent TKA using a dynamic ligament tensioning robotic system with a tibia first resection technique and a cruciate sacrificing ultracongruent TKA system were enrolled into a prospective study. Each TKA was graded based on the final mediolateral ligament balance at 10° and 90° of flexion: 1) < 1 mm difference in the thickness of the tibial insert and that which was planned (n = 75); 2) < 1 mm difference (n = 26); 3) between 1 mm to 2 mm difference (n = 26); and 4) > 2 mm difference (n = 7). The mean one-year KPS score for each grade of TKA was compared and the likelihood of achieving an KPS score of > 90 was calculated. Finally, the factors associated with lower KPS despite achieving a high-grade TKA (grade A and B) were analyzed. Results. Patients with a grade of A or B TKA had significantly higher mean one-year KPS scores compared with those with C or D grades (p = 0.031). There was no difference in KPS scores in grade A or B TKAs, but 33% of these patients did not have a KPS score of > 90. While there was no correlation with age, sex, preoperative deformity, and preoperative KOOS and Patient-Reported Outcomes Measurement Information System (PROMIS) physical scores, patients with a KPS score of < 90, despite a grade A or B TKA, had lower PROMIS mental health scores compared with those with KPS scores of > 90 (54.1 vs 50.8; p = 0.043). Patients with grade A and B TKAs with KPS > 90 were significantly more likely to respond with “my expectations were too low”, and with “the knee is performing better than expected” compared with patients with these grades of TKA who had a KPS score of < 90 (40% vs 22%; p = 0.004). Conclusion. A TKA balanced with robotic assistance to within 1 mm of difference between the medial and lateral sides in both flexion and extension had a higher KPS score one year postoperatively. Despite accurate ligament balance information, a robotic system could not guarantee excellent pain relief. Patient expectations and mental status also significantly affected the perceived success of TKA. Cite this article: Bone Joint J 2021;103-B(6 Supple A):67–73

Introduction. Neither a surgeon's intraoperative impression or computer navigation parameters have been shown to be predictive of postoperative outcomes following TKA. The purpose of this study is to determine 1) whether a surgeon and a robot can predict the 1-year KOOS pain score (KPS) and 2) determine what factors correlate with poor KOOS scores in well aligned and balanced TKA. Methods. The data of 131 consecutive patients enrolled in a prospective trial was reviewed. All TKAs were performed using a dynamic ligament tensioning robotic system with a tibial first resection technique and a cruciate sacrificing ultracongruent knee implant. Each TKA was graded based on the final recorded mediolateral ligament balance at 10° and 90°: A) <1mm with an implanted insert thickness equal to planned (n=74); B) <1mm (n=25); C) <2mm (n=26); D) >2mm (n=6) (Table-1). The 1-year KPS for each knee grade were compared and the likelihood of achieving an KPS > 90 was calculated. Finally, the factors associated with lower KPS despite achieving a high grade TKA (A/B) was performed. The Mann-Whitney U test and Chi-squared analysis was performed. Results. Patients with a grade of A and B had higher 1-year KPS compared to knees rated C and D (p=0.031) (Fig-1). There was no difference in KPS in TKAs rated A or B, but 33% in this group did not report a KPS > 90. While there was no correlation with age, sex, preoperative deformity, and preoperative KOOS and PROMIS physical scores, patients with KPS < 90 despite a TKA rated A or B had lower PROMIS metal health scores compared to patients reporting KPS > 90 (54.1 vs. 50.8, p= 0.043). Finally, Grade A and B patients who scored KPS > 90 were more likely to respond with “my expectations were too low”, and they are performing better than expected compared to Grade A and B patients who scored KPS < 90 (40% vs 22%, p = 0.004). Summary. A robotic balanced knee is correlated with higher KPS at 1 year but not predictive. Despite accurate alignment, rotation, and ligament balance information, a robotic system could not guarantee excellent pain relief. Patient expectations and mental status also significantly affect the perceived success of TKA. For any figures or tables, please contact the authors directly

Introduction. Porous metaphyseal cones are increasingly used for fixation in revision total knee arthroplasty (RTKA). Both cemented shorter length stems and longer diaphyseal engaging stems are currently utilized with metaphyseal cones with no clear evidence of superiority. The purpose of this study was to evaluate our experience with 3D printed titanium metaphyseal cones with both short cemented and longer cementless stems from a clinical and radiographic perspective. Methods. In total 136 3D printed titanium metaphyseal cones were implanted. The mean patient age was 63 and 48% were female. The mean BMI was 33 and the mean ASA class was 2.5. There were 42 femoral cones in which 28 cemented and 14 cementless stems were utilized. There were 94 tibial cones in which 67 cemented and 27 cementless stems were utilized. The choice for stem fixation was surgeon dependent and in general cones were utilized for AORI type 2 and 3 bone defects on the femur and tibia. The most common fixation scenario was short cemented stems on both the femur and tibia followed by cemented stem fixation on the tibia and cementless fixation on the femur. Clinical data such as revision, complication, and PRO was collected at last follow-up (minimum follow-up 1 year). Radiographic analysis included cone bony ingrowth and coronal and sagittal alignment on long-standing radiographs. Descriptive statistics were used to compare demographics between patients who had malalignment (HKA beyond +/− 3 degrees and flexion/extension beyond +/− 3 degrees). Adjusted logistic regression models were run to assess malalignment risk by stem type. Results. Patient reported outcomes demonstrated modest improvements with Pre-op KOOS improving from 44 pre-op to 59 post -op and PF-CAT improving from 33 to 37 post-op. PROMIS pain scores decreased significantly from 54 to 44 post-op. 36% of patients had malalignment in either the coronal or sagittal plane. Patients with malalignment were more likely to be female (66.7% vs 40.4%, p-value=0.02). After adjusting for age, sex and BMI, there was a significantly increased risk for coronal plane malalignment when both the femur and tibia had cementless compared to cemented stems (odds ratio=5.54, 95%CI=1.15, 26.80). There was no significantly increased risk when comparing patients with mixed stems to patients with cemented stems. Sagittal plane malalignment was more common with short cemented stems although both coronal plane and sagittal plane malalignment with either stem type was not associated with inferior clinical outcome. Overall cone survivorship was excellent with only two cones removed for infection. Conclusion. Metaphyseal titanium cones provide reliable fixation in revision TKA. However, PROs in this complex patient population show only modest improvement consistent with other variables such as co-morbidities and poor baseline physical function. Small cone inner diameter may adversely influence cementless stem position leading to coronal plane malalignment. Short cemented stems are subject to greater sagittal plane malalignment with no apparent influence on clinical outcome

Introduction. Total knee arthroplasty (TKA) reliably improves pain and function in patients with knee osteoarthritis (OA), though a substantial percentage of patients remain unsatisfied. Reasons include the presence of complications, persistent pain, and unmet expectations. The aim of this study was to determine whether the sequential addition of accelerometer-based navigation of the distal femoral cut and sensor-assisted soft tissue balancing changed complication rates, radiographic alignment, or patient-reported outcomes (PROs) compared to TKA performed with conventional instrumentation. Methods. This retrospective cohort study included 371 TKAs in 319 patients. All surgeries were performed by a single surgeon in sequential fashion using a measured resection technique with a goal of mechanical alignment. The historical control group, utilizing intramedullary guides for distal femoral resection and surgeon-guided soft tissue balancing, was compared to group 1 (accelerometer-based navigation for distal femoral resection, surgeon-guided balancing) and group 2 (navigated femoral resection, sensor-guided balancing). Primary outcome measures were PROMIS scores including physical function computerized adaptive test (PF CAT), and the Global 10 health assessment (including physical, mental, and pain scores), and Knee Injury Osteoarthritis and Outcome Score (KOOS), measured preoperatively and at 6 weeks and 12 months postoperatively. Radiographic measurements included component position and overall mechanical alignment of the limb and were made at 6 weeks by a single examiner from hip to ankle standing films. Charts were reviewed for pre- and postoperative ROM at 6 weeks, polyethylene insert morphology, and postoperative hematocrit change. Complications were recorded, including manipulation under anesthesia and reoperation. Our study was powered to detect a difference of 1 standard deviation in PF CAT score with 100 patients. Statistical analysis was performed by a statistician including t-tests, multivariate regression, and time series plot analyses. Results. There were 194 patients in the control group, 103 in group 1, and 74 in group 2. There was no difference in baseline patient demographics. Patients in group 2 had higher baseline mental health subscores than control and group 1 patients (53.2 vs 50.2 vs 50.2, p=0.04). There were no differences in 6-week and one-year postop PF CAT, physical or mental subscores, pain scores, or KOOS scores (all p>0.05). There were 8 total complications in the control group (4.1%), 4 in group 1 (3.8%), and 1 in group 2 (1.4%) (p>0.4). The postoperative mechanical axis of the limb was within 3 degrees of neutral in 71.6% of control patients, 74.8% in group 1, and 85.1% in group 2 (p=0.1). There was no difference in femoral component coronal alignment between groups (p=0.91), though controls had a small but significantly higher degree of flexion in the sagittal plane (6.5 degrees) than groups 1 and 2 (5.4 degrees in both, p=0.003). There was no difference in postoperative ROM or blood loss. Conclusions. The sequential addition of imageless navigation of the distal femoral cut and sensor-guided ligament balancing did not confer any benefit to short term PROs, radiographic outcomes, or complication rates over conventional techniques. While overall mechanical alignment of the limb was improved in groups 1 and 2 compared to controls, this did not reach statistical significance. The additive costs of navigation and soft-tissue balancing technologies may not be justified. For figures, tables, or references, please contact authors directly

Aims

To map the Oxford Knee Score (OKS) and High Activity Arthroplasty Score (HAAS) items to a common scale, and to investigate the psychometric properties of this new scale for the measurement of knee health.

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The optimal bearing surface design for medial unicompartmental knee arthroplasty (UKA) remains controversial. The aim of this study was to compare outcomes of fixed-bearing (FB) and mobile-bearing (MB) UKAs from a single high-volume institution.

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The metabolic equivalent of task (MET) score examines patient performance in relation to energy expenditure before and after knee arthroplasty. This study assesses its use in a knee arthroplasty population in comparison with the widely used Oxford Knee Score (OKS) and EuroQol five-dimension index (EQ-5D), which are reported to be limited by ceiling effects.

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To map literature on prognostic factors related to outcomes of revision total knee arthroplasty (rTKA), to identify extensively studied factors and to guide future research into what domains need further exploration.

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Although total knee arthroplasty (TKA) is a highly successful procedure, about 20% of patients remain dissatisfied postoperatively. This proportion is derived from dichotomous models of the assessment of surgical success or failure, which may not reflect the spectrum of outcomes. The aim of this study was to explore differing responses to surgery, and assess whether there are distinct groups of patients with differing patterns of outcome.

Aims

A significant percentage of patients remain dissatisfied after total knee arthroplasty (TKA). The aim of this study was to determine whether the sequential addition of accelerometer-based navigation for femoral component preparation and sensor-guided ligament balancing improved complication rates, radiological alignment, or patient-reported outcomes (PROMs) compared with a historical control group using conventional instrumentation.

Aims

Responsiveness to clinically important change is a key feature of any outcome measure. Throughout Europe, health-related quality of life following total knee arthroplasty (TKA) is routinely measured with EuroQol five-dimension (EQ-5D) questionnaires. The Patient-Reported Outcomes Measurement Information System 10-Question Short-Form (PROMIS-10 Global Health) score is a new general heath outcome tool which is thought to offer greater responsiveness. Our aim was to compare these two tools.