Clinical Frailty Scale is a better predictor for adverse post-operative complications and functional outcomes than Modified Frailty Index and Charlson Comorbidity Index after total knee arthroplasty.

PURPOSE: Studies have demonstrated correlations between frailty and comorbidity scores with adverse outcomes in total knee replacement (TKR). However, there is a lack of consensus on the most suitable pre-operative assessment tool. This study aims to compare Clinical Frailty Scale (CFS), Modified Frailty Index (MFI), and Charlson Comorbidity Index (CCI) in predicting adverse post-operative complications and functional outcomes following a unilateral TKR. METHODS: In total, 811 unilateral TKR patients from a tertiary hospital were identified. Pre-operative variables were age, gender, body mass index (BMI), American Society of Anesthesiologists (ASA) class, CFS, MFI, and CCI. Binary logistic regression analysis was performed to ascertain odd ratios of pre-operative variables on adverse post-operative complications (length of stay < LOS >, complications, ICU/HD admission, discharge location, 30-day readmission, 2-year reoperation). Multiple linear regression analyses were used to estimate the standardized effects of pre-operative variables on the Knee Society Functional Score (KSFS), Knee Society Knee Score (KSKS), Oxford Knee Score (OKS), and 36-Item Short Form Survey (SF-36). RESULTS: CFS is a strong predictor for LOS (OR 1.876, p < 0.001), complications (OR 1.83-4.97, p < 0.05), discharge location (OR 1.84, p < 0.001), and 2-year reoperation rate (OR 1.98, p < .001). ASA and MFI were predictors for ICU/HD admission (OR:4.04, p = 0.002; OR 1.58, p = 0.022, respectively). None of the scores was predictive for 30-day readmission. A higher CFS was associated with a worse outcome for 6-month KSS, 2-year KSS, 6-month OKS, 2-year OKS, and 6-month SF-36. CONCLUSION: CFS is a superior predictor for post-operative complications and functional outcomes than MFI and CCI in unilateral TKR patients. This suggests the importance of assessing pre-operative functional status when planning for TKR. LEVEL OF EVIDENCE: Diagnostic, II.

The effect of topical tranexamic acid on functional outcomes and quality of life in patients undergoing unicompartmental knee arthroplasty.

INTRODUCTION: Tranexamic acid (TXA) is being increasingly utilized to reduce blood loss after knee joint arthroplasty. However, there is a lack of studies on the effect of topical TXA on the functional outcomes and quality of life after Unicompartmental Knee Arthroplasty (UKA). The aim of this study was to determine the effect of topical TXA on functional outcomes and quality of life scores in patients undergoing UKA. MATERIALS AND METHODS: We retrospectively analysed patients undergoing unilateral UKA at a single tertiary hospital from 2005 to 2017. Patients were divided into 2 groups: (1) The control group which did not receive TXA (n = 742); (2) The TXA group which received topical TXA (n = 331). Functional outcomes were assessed using the Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS) and Oxford Knee Score (OKS), while quality of life was evaluated with the Physical Component Score (PCS) and Mental Component Score (MCS) of Short-Form 36 (SF-36) preoperatively and at 6 months and 2 years follow-up. RESULTS: At 6 months and 2 years post-surgery, there were no significant differences in the functional scores between the groups. The number of patients who attained minimum clinically important difference (MCID) for each of the functional scores was also comparable between the groups. CONCLUSIONS: In patients undergoing UKA, functional outcomes and quality of life scores were comparable between those who received topical TXA and those who did not. There was no significant improvement or impairment in knee function associated with topical TXA administration in UKA up to 2 years follow-up.

Similar postoperative outcomes after total knee arthroplasty with measured resection and gap balancing techniques using a contemporary knee system: a randomized controlled trial.

PURPOSE: The Attune® Knee System provides new instrumentation to achieve symmetric flexion/extension gaps in total knee arthroplasty (TKA). However, there is limited information on the optimal TKA technique using this system. The aim of this randomised controlled trial was to determine which surgical technique results in better postoperative clinical outcomes after TKA using the contemporary Attune® Knee System: the measured resection or gap balancing technique. METHODS: A prospective randomized controlled trial was conducted with 100 patients undergoing TKA using measured resection (n = 50) or gap balancing (n = 50) technique. The measured femoral sizer was used in the measured resection group, while the balanced femoral sizer was used in the gap balancing group. Functional outcomes and quality of life were assessed preoperatively and at 6 months and 2 years post-surgery, using the Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS), Oxford Knee Score (OKS), the Physical Component Score (PCS) and Mental Component Score (MCS) of Short-Form 36 (SF-36). Using weight-bearing coronal radiographs, the hip-knee-ankle angle (HKA), coronal femoral component angle (CFA), coronal tibial component angle (CTA) and joint line height were also evaluated for each patient. RESULTS: There were no significant differences in the functional scores or the proportion of patients from each group who were satisfied or had their expectations fulfilled at 6 months or 2 years post-surgery. There was also no significant difference in the number of patients who attained minimum clinically important difference (MCID) postoperatively between the groups. Postoperatively, there was no significant difference in the number of HKA outliers between the groups (p = 0.202). The postoperative CFA (p = 0.265) and CTA (p = 0.479) were similar between the groups. There was also no significant difference in the absolute change (p = 0.447) or proportion of outliers (p = 0.611) for joint line height between the groups. CONCLUSION: Both measured resection and gap balancing techniques resulted in comparable functional and quality of life outcomes up to 2 years post-surgery. Both techniques appear to be equally effective in achieving excellent outcomes with the Attune® Knee System. LEVEL OF EVIDENCE: I.

Mid-term functional outcomes of patient-specific versus conventional instrumentation total knee arthroplasty: a prospective study.

INTRODUCTION: Patient-specific instrumentation (PSI) utilizes three-dimensional imaging to produce total knee arthroplasty cutting jigs which matches patient's native anatomy. However, there are limited mid- to long-term studies examining its clinical efficacy. The aim of this study was to compare functional outcomes of PSI surgery versus conventional TKA surgery at 5-year follow-up. MATERIALS AND METHODS: Sixty patients were prospectively recruited into either the MRI-based PSI or conventional TKA group. Functional outcomes were assessed using the Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS) and Oxford Knee Score (OKS), while quality of life was evaluated with the Physical Component Score (PCS) and Mental Component Score (MCS) of Short-Form 36 and compared between the two groups at 5-year follow-up. RESULTS: Although the PCS was 7 ± 3 points better in the PSI group preoperatively (p = 0.017), it became 5 ± 2 points worse than the conventional group at 5-year follow-up (p = 0.025). As compared to the PSI group, the conventional group showed a significantly greater improvement in PCS at 5 years as compared to before surgery (p = 0.003). There were no significant differences in KSFS, KSKS, OKS or MCS between the two groups. CONCLUSIONS: PSI TKA did not result in improved functional outcomes or better quality of life when compared to conventional TKA. The additional costs and waiting time associated with PSI are not justifiable and therefore not recommended as an alternative to conventional TKA. LEVEL OF EVIDENCE: II.

Should patients aged 75 years or older undergo medial unicompartmental knee arthroplasty? A propensity score-matched study.

INTRODUCTION: With increasing life expectancies worldwide, more elderly patients with isolated medial compartment osteoarthritis may become suitable UKA candidates. However, there is a paucity of literature comparing outcomes between older patients (≥ 75 years) and younger patients undergoing UKA. The aim of this study was to determine if there were differences in functional and HRQoL measures between older patients (≥ 75 years) and younger controls (< 75 years) undergoing primary UKA. MATERIALS AND METHODS: Prospectively collected registry data of 1041 patients who underwent primary, cemented, fixed-bearing medial UKA at a single institution from 2002-2013 were reviewed. Propensity scores generated using logistic regression was used to match older patients (≥ 75 years, n = 94) to controls (< 75 years, n = 188) in a 1:2 ratio. Knee Society Scores, Oxford Knee Score, Short Form-36, satisfaction/expectation scores, proportion of patients attaining OKS/SF-36 PCS MCID and survivorship were analysed. RESULTS: Patients ≥ 75 years had significantly lower KSFS (67.1 ± 17.9 vs 79.4 ± 18.2, p < 0.001) and SF-36 PCS (47.3 ± 10.1 vs 50.4 ± 9.1, p = 0.01) as compared to the control group. In addition, a significantly lower proportion of patients ≥ 75 years attained MCID for SF-36 PCS when compared to the controls (50.0% vs 63.8%, p = 0.04). Survival rates at mean 8.3 ± 3.0 years were 98.9% (95% CI, 96.7-100) in the older group versus 92.8% (95% CI, 86.8-98.8) in the younger group (p = 0.31). CONCLUSIONS: Our findings highlight the need to counsel older patients regarding potentially reduced improvements in functional outcomes, despite advantages of lower revision. However, UKA in older patients continues to be a viable option for isolated medial compartment osteoarthritis LEVEL OF EVIDENCE: Level III Propensity score matched study.

Increased constraint of rotating hinge knee prosthesis is associated with poorer clinical outcomes as compared to constrained condylar knee prosthesis in total knee arthroplasty.

The aim of this study was to evaluate whether there are any differences in patient-reported outcome measures between semi-constrained condylar constrained knee (CCK) and fully constrained rotating hinge knee (RHK) prostheses in midterm follow-up. We reviewed prospectively collected data of our hospital arthroplasty registry between 2007 and 2014. Thirty-nine patients were identified to have RHK prosthesis TKA and matched for a number of primary/revision TKA, gender, age, body mass index and pre-operative clinical scores to a control group of 78 patients with CCK TKA. Patient demographics, range of movement, varus/valgus deformity, Short Form 36 (SF-36) scores, Oxford Knee Score (OKS), Knee Society Score (KSS) and patient satisfaction were evaluated. Pre-operatively, the RHK and the control group of CCK had similar demographics, proportion of primary/revision TKA and baseline clinical scores (p > 0.05). At 2-year follow-up, patients with CCK prostheses had significantly better clinical outcomes as compared to patients with RHK prosthesis in terms of KSS functional scores, OKS, SF-36 sub-domains of physical functioning, physical role functioning and physical component score. We conclude that at midterm follow-up of 2 years, the CCK patients as compared to RHK patients reported better clinical and functional outcomes in terms of OKS, KSS functional score and SF-36 with a greater proportion of patients who were satisfied and had their expectations met by surgery. Further biomechanical studies are needed to investigate the association between component constraint and clinical outcomes for these prostheses.

Pre-existing patellofemoral disease does not affect 10-year survivorship in fixed bearing unicompartmental knee arthroplasty.

PURPOSE: The purpose of this study was to assess 10-year functional outcome and survivorship analysis of patients with significant radiographic evidence of patellofemoral joint arthritis treated with fixed bearing unicompartmental knee arthroplasty. METHODS: Two hundred and sixteen patients (263 knees) that underwent UKA from 2003 to 2005 for a mean of 10.5 ± 2.1 years were prospectively followed up. Preoperative radiological assessment of the patellofemoral joint state was assessed according to the Ahlback classification by an independent assessor and radiographically significant patellofemoral disease was defined as grade 2 or more. Patients with significant bone-on-bone contact in the patellofemoral joint were excluded. RESULTS: Of the 263 knees, 222 (84.4%) had normal patellofemoral joint state and 41 (15.6%) radiologically significant patellofemoral disease. At 10 years' follow-up, the normal and patellofemoral groups had similar OKS (20 ± 7 vs 20 ± 8, n.s.) and KSS scores (79 ± 20 vs 81 ± 20, n.s.), respectively. There were 12 revision surgeries in the normal group and the most common indication for revision was progression of contralateral compartment osteoarthritis (6 of 12 cases). There was only one revision in the patellofemoral group and it was due to progression of contralateral compartment osteoarthritis (n.s.). When all secondary surgeries to the operated knee were considered as failures, the 10-year survival rate was 95.1% (CI 95%: 92.2-97.7%). CONCLUSION: The presence of significant preoperative radiological patellofemoral disease does not affect long-term implant survival and patients have excellent functional outcomes 10 years postoperatively. These patients should not be contraindicated from undergoing unicompartmental knee arthroplasty. LEVEL OF EVIDENCE: III.

Postoperative fixed flexion deformity greater than 10° lead to poorer functional outcome 10 years after unicompartmental knee arthroplasty.

PURPOSE: The primary aim of this study was to evaluate the influence of postoperative fixed flexion deformity (FFD) on the clinical outcomes 10 years after unicompartmental knee arthroplasty (UKA). The secondary aim was to identify predictors for the occurrence of postoperative FFD. METHODS: Patients who underwent UKA between 2003 and 2007 were prospectively followed up for 10 years. A total of 172 patients were categorized into 3 groups based on the amount of postoperative FFD: (1) 0° or less (Min-FFD), (2) 1°-9° (Mid-FFD), and (3) 10° or more (Max-FFD). Functional outcome was quantified using Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS) and Oxford Knee Score (OKS). RESULTS: At 10 years after UKA, the mean KSKS and OKS were 6 ± 5 (95% CI 6-18, p = 0.050) and 5 ± 2 (95% CI 0-9, p = 0.041) points lower in patients with Max-FFD than those with Min-FFD. Other clinical outcomes were not different between groups. Patients with a higher preoperative body mass index (OR 1.122 per unit increase, 95% CI 1.006-1.253, p = 0.040) or worse preoperative FFD (OR 1.108 per unit increase, 95% CI 1.022-1.201, p = 0.013) were at increased risk of having postoperative FFD of 10° or more at 10 years after UKA. CONCLUSIONS: The clinical relevance of this study was to demonstrate the long-term negative correlation between severe postoperative FFD and functional outcome and, therefore, the importance of achieving good knee alignment after UKA. The authors recommend that FFD should be fully corrected intra-operatively if possible while preserving knee balance and stable dynamic function through full range of motion. LEVEL OF EVIDENCE: Prognostic level II.

Change in Body Mass Index After Total Knee Arthroplasty and Its Influence on Functional Outcome.

BACKGROUND: There is often an assumption by patients that weight loss will occur once their knee pain is relieved by total knee arthroplasty (TKA). This study aims to evaluate (1) the change in patients' body mass index (BMI) after TKA; (2) if postoperative change in BMI influences functional outcome and survival rate of TKA; and (3) the predictive factors associated with change in BMI. METHODS: Seven thousand seven hundred thirty-three patients who underwent a primary TKA between 2001 and 2010 were included in this study. Functional outcome scores collected at 2 years after surgery include the Oxford Knee Score, Knee Society Function Score, Knee Society Knee Score, Physical Component Score, and Mental Component Score of short form 36. RESULTS: Among these patients, 1067 (14%) had reduction in BMI, 5045 (65%) maintained their BMI, and 1621 (21%) had gain in BMI. The differences in improvement in Oxford Knee Score, Knee Society Function Score, Knee Society Knee Score, and Physical Component Score among the 3 groups of patients were less than the known minimal clinically important difference of these scores. The 10-year survival rate of TKA was not influenced by patients' change in BMI after surgery (P = .435). Obese class I, II, and III patients were more likely to reduce their BMI after TKA than those with normal preoperative BMI (P = .002, P = .012, and P = .004, respectively), while older patients were less likely to have gain in BMI after surgery (P = .001). CONCLUSION: A change in BMI after TKA did not influence the functional outcome clinically or the survival rate of the TKA implant.

Unicompartmental Knee Arthroplasty Achieves Greater Flexion With No Difference in Functional Outcome, Quality of Life, and Satisfaction vs Total Knee Arthroplasty in Patients Younger Than 55 Years. A Propensity Score-Matched Cohort Analysis.

BACKGROUND: Improvements in surgical techniques, implant design, and adherence to indications have resulted in favorable outcomes after unicompartmental knee arthroplasty (UKA), particularly in an older population. However, no studies have compared the performance of contemporary UKA and total knee arthroplasty (TKA) in a young population. METHODS: Prospectively collected registry data of 160 UKAs performed in 160 patients younger than 55 years were reviewed. Propensity scores generated using logistic regression were used to adjust for confounding variables of age, gender, body mass index, preoperative range of motion, Knee Society Score, Oxford Knee Score, and Short-Form 36, allowing matching of the TKA cohort to the UKA cohort in a 1:1 ratio using the nearest-neighbor method. RESULTS: The UKA group had significantly greater flexion at 6 months and 2 years (P < .001). There was no significant difference in Knee Society Score, Oxford Knee Score, and Short-Form 36. At 2 years, 89.4% and 88.8% of the TKA and UKA groups were satisfied (P = 1.00) while 86.9% and 86.3% had their expectations fulfilled (P = 1.00). At a mean follow-up of 7 years, there were 2 revisions in each group (2.2%). CONCLUSION: Although native knee biomechanics are preserved, younger patients do not seem to perceive this oft-cited benefit of UKA, as this did not translate into greater health-related quality of life or patient satisfaction compared to TKA. The theoretical advantages of UKA were not borne out by our findings, other than greater flexion up to 2 years postoperatively.

Outcomes following total knee arthroplasty with CT-based patient-specific instrumentation.

PURPOSE: A 24-month prospective follow-up study was carried out to compare perioperative clinical outcomes, radiographic limb alignment, component positioning, as well as functional outcomes following total knee arthroplasty (TKA) between patient-specific instrumentation (PSI) and conventional instrumentation (CI). METHODS: Ninety consecutive patients, satisfying the inclusion and exclusion criteria, were scheduled to undergo TKA with either PSI or CI. A CT-based PSI was used in this study, and a senior surgeon performed all surgeries. Patients were clinically and functionally assessed preoperatively, 6 and 24 months post-operatively. Perioperative outcomes were also analysed, including operating time, haemoglobin loss, the need for blood transfusion, length of hospitalisation, and radiographic features. RESULTS: At 24-month follow-up, clinical and functional outcomes were comparable between the two groups. PSI performed no better than CI in restoring lower limb mechanical alignment or improving component positioning. There were no differences in operating time, haemoglobin loss, transfusion rate, or length of hospitalisation between PSI and CI. CONCLUSION: No significant clinical benefit could be demonstrated in using PSI over CI after 24 months, and routine use of PSI is not recommended in non-complicated TKA. LEVEL OF EVIDENCE: II.

The accuracy of a hand-held navigation system in total knee arthroplasty.

INTRODUCTION: This study aims to evaluate the effectiveness of a new hand-held navigation system. The authors of this study hypothesize that this navigation system will improve overall lower limb alignment and implant placement without causing a delay in surgery. PATIENTS AND METHODS: Two hundred consecutive patients diagnosed with tricompartmental osteoarthritis and underwent total knee arthroplasty by a senior surgeon were included in this study. One hundred patients underwent TKA using the hand-held navigation system, while the other 100 patients underwent TKA using the conventional technique. The primary outcomes of this study were the overall alignment of the lower limb and the position of the components. This was determined radiologically using the: (1) Hip-Knee-Ankle angle (HKA) for lower limb alignment; (2) Coronal Femoral-Component angle (CFA); and (3) Coronal Tibia-Component angle (CTA) for component position. Normal alignment was taken as 180° ± 3° for the HKA and 90° ± 3° for both the CFA and CTA. RESULTS: For the CFA, the proportion of outliers was 7 and 17% in the hand-held navigation and conventional group, respectively (p = 0.030). For the HKA and CTA, there was no difference in the proportion of outliers between the two groups. The duration of surgery was 73 ± 9 min and 87 ± 15 min in the hand-held navigation and conventional group, respectively (p < 0.001). CONCLUSION: This hand-held navigation system is an effective intraoperative tool for reducing the proportion of outliers for femoral implant placement as well as the duration of surgery. The authors conclude that it can be considered for use to check femoral implant placement intra-operatively. LEVEL OF EVIDENCE: III.

Preoperative haemoglobin cut-off values for the prediction of post-operative transfusion in total knee arthroplasty.

PURPOSE: The purpose of this study is to determine preoperative haemoglobin cut-off values that could accurately predict post-operative transfusion outcome in patients undergoing primary unilateral total knee arthroplasty (TKA). This will allow surgeons to provide selective preoperative type and screen to only patients at high risk of transfusion. METHODS: A total of 1457 patients diagnosed with osteoarthritis and underwent primary unilateral TKA between January 2012 and December 2014 were retrospectively reviewed. Logistic regression analyses were applied to identify factors that could predict transfusion outcome. RESULTS: A total of 37 patients (2.5 %) were transfused postoperatively. Univariate analysis revealed preoperative haemoglobin (p < 0.001), age (p < 0.001), preoperative haematocrit (p < 0.001), and preoperative creatinine (p < 0.001) to be significant predictors. In the multivariate analysis with patients dichotomised at 70 years of age, preoperative haemoglobin remained significant with adjusted odds ratio of 0.33. Receiver operating characteristic curve identified the preoperative haemoglobin cut-off values to be 12.4 g/dL (AUC = 0.86, sensitivity = 87.5 %, specificity = 77.2 %) and 12.1 g/dL (AUC = 0.85, sensitivity = 69.2 %, specificity = 87.1 %) for age above and below 70, respectively. CONCLUSIONS: The authors recommend preoperative haemoglobin cut-off values of 12.4 g/dL for age above 70 and 12.1 g/dL for age below 70 to be used to predict post-operative transfusion requirements in TKA. To maximise the utilisation of blood resources, the authors recommend that only patients with haemoglobin level below the cut-off should receive routine preoperative type and screen before TKA. LEVEL OF EVIDENCE: IV.

Minimally Invasive Computer-Assisted Total Knee Arthroplasty Compared With Conventional Total Knee Arthroplasty: A Prospective 9-Year Follow-Up.

BACKGROUND: Studies on minimally invasive computer-assisted total knee arthroplasty (MICA-TKA) have shown promising results, but are limited by short follow-up. The purpose of this study was to compare the midterm radiographic features and functional outcomes between patients who underwent MICA-TKA and conventional TKA. METHODS: A total of 108 patients who were randomized to undergo MICA-TKA or conventional TKA during 2004 and 2005 were contacted for a prospective follow-up review. Patients who were lost to contact, have passed away, or declined to participate in the study were excluded. Objective functional measurements and radiographs were obtained for assessment. RESULTS: By the time of this study, 2 patients from the conventional group had undergone revision TKA, one due to infection and one due to aseptic loosening. A total of 67 patients (62.04%) were followed up for an average period of 9.07 years (8.51-9.61 years). At follow-up, functional scores were comparable between the 2 groups. No significant intergroup differences were found in mechanical knee alignment and component placement angle in the coronal views. No statistical or clinical significance were noticed in radiographic signs of component loosening. CONCLUSIONS: MICA-TKA provided similar clinical, functional, and radiographic outcomes compared with conventional TKA after an average of 9-year follow-up. This technique can be used to exploit its short-term advantages without compromising midterm outcomes.

Fixed Flexion Deformity After Unicompartmental Knee Arthroplasty: How Much Is Too Much.

BACKGROUND: The detrimental impact of postoperative fixed flexion deformity (FFD) after unicompartmental knee arthroplasty (UKA) is manifold. This study aims to define the amount of postoperative FFD that is clinically relevant after UKA. METHODS: Between 2005 and 2012, 803 patients who underwent a primary UKA at a tertiary hospital were prospectively followed up. They were categorized into 3 groups based on the amount of postoperative FFD: (1) 0° (control); (2) 1°-10° (mild FFD); and (3) >10° (severe FFD). RESULTS: There were 26 patients (3%) with severe FFD at 2 years after UKA. The Knee Society Function Score and Knee Score in the severe FFD group were 10 ± 4 and 10 ± 2 points lower than in the control group, respectively (P = .017 and P = .001). Similarly, the Oxford Knee Score and Physical Component Score in the severe FFD group was 5 ± 1 and 7 ± 2 points lower than in the control group, respectively (P = .033 and P < .001). CONCLUSION: This study suggests that postoperative FFD of >10° after UKA is associated with significantly poorer functional outcomes.

Early Outcomes of Unicompartmental Knee Arthroplasty in Patients With Preoperative Genu Recurvatum of Non-neurological Origin.

BACKGROUND: This study aims to evaluate outcomes of unicompartmental knee arthroplasty (UKA) in patients with preoperative genu recurvatum. METHODS: From patients who underwent UKA at a tertiary hospital between 2005 and 2012, the study selected 30 patients with genu recurvatum (group A) compared with a matching cohort of 60 without genu recurvatum (group B). Group A was also compared with a matched cohort of 60 patients with genu recurvatum who underwent total knee arthroplasty (group C). Functional outcomes data were prospectively collected at 6-month and 2-year follow-up. RESULTS: Two years after UKA, group A had poorer Oxford Knee Score of 22 ± 8 compared with group B at 16 ± 3 (P < .001), and the trend is reflected in the Knee Society Score (71 ± 17 vs 87 ± 17, P < .001) and the 36 Item Short Form Health Survey Physical Component Score (47 ± 10 vs 52 ± 6, P = .014). After 2 years, group C had superior Oxford Knee Score (16 ± 2, P < .001), Knee Society Score (82 ± 14, P = .003), and 36 Item Short Form Health Survey Physical Component Score (53 ± 6, P = .005). The hyperextension angle in group A decreased from 6° ± 2° to 2° ± 4° after 2 years with an improvement of 4° ± 4° (P < .001). The hyperextension angle in group C decreased from 7° ± 2° to 1° ± 3° after 2 years with an improvement of 6° ± 3° (P < .001) with a significant difference (P = .002) in hyperextension angle correction between group A and C. CONCLUSION: Preoperative recurvatum is a predictor of poorer outcome after UKA, and this patient population benefits from better 2-year functional outcomes after total knee arthroplasty.

Cruciate retaining versus posterior stabilized total knee arthroplasty after previous high tibial osteotomy.

PURPOSE: This study aimed to investigate the clinical outcome of total knee arthroplasty (TKA) after previous high tibial osteotomy (HTO) using cruciate retaining (CR) versus posterior stabilized (PS) prostheses. METHODS: Between 2001 and 2010, 133 patients who underwent TKA after previous HTO were included in this study and prospectively followed up for two years. Two independent assessors recorded the range of motion of the operated knee, anterior-posterior (AP) laxity, medial-lateral (ML) laxity, Oxford Knee Score (OKS), Knee Society Function Score (KSFS) and Knee Society Knee Score (KSKS). RESULTS: Thirty-three patients received CR prostheses, while 100 patients received PS prostheses. The median (inter-quartile range) knee flexion at 6 months and 2 years post-TKA was 101° (90, 116) and 110° (90, 118), respectively for the CR group, compared to 115° (100, 121) and 118° (108, 125) for the PS group (p = 0.010 and p = 0.009, respectively). AP and ML laxities were comparable in both groups of patients. While both groups of patients showed improvement in OKS, KSFS and KSKS at 6 months and 2 years post-TKA, there was no significant difference in these clinical scores between the two groups at both time points of follow-up. None of the 133 patients required revision surgery. CONCLUSIONS: Although PS prostheses offer better knee flexion in TKA after previous HTO, the knee stability, clinical scores and revision rate at 6 months and 2 years post-TKA are comparable between CR and PS prostheses. The authors conclude that CR is an alternative to PS prostheses in patients undergoing TKA after previous HTO. LEVEL OF EVIDENCE: III.

Radiological outcomes of pinless navigation in total knee arthroplasty: a randomized controlled trial.

PURPOSE: This study aimed to investigate the accuracy of pinless navigation (BrainLAB(®) VectorVision(®) Knee 2.5 Navigation System) as an intra-operative alignment guide in total knee arthroplasty (TKA). The authors hypothesized that pinless navigation would reduce the proportion of outliers in conventional TKA, without a significant increase in the duration of surgery. METHODS: Between 2011 and 2012, 100 patients scheduled for a unilateral primary TKA were randomized into two groups: pinless navigation and conventional surgery. All TKAs were performed with the surgical aim of achieving neutral coronal alignment with a 180° mechanical axis. The primary outcomes of this study were post-operative radiographic assessment of lower limb alignment using hip-knee-ankle angle (HKA) and components placement using coronal femoral-component angle (CFA) and coronal tibia-component angle (CTA). RESULTS: There was a smaller proportion of outliers for HKA, CFA and CTA at 10, 2 and 2 % respectively, in the pinless navigation group, compared to 32, 16 and 16 %, respectively, in the conventional group (p = 0.013, p = 0.032 and p = 0.032, respectively). The mean CFA was also more accurate at 90° in the pinless navigation group compared to 91° in the conventional group (p = 0.002). There was no difference in the duration of surgery between the two groups (n.s.). CONCLUSIONS: Pinless navigation improves lower limb alignment and components placement without a significant increase in the duration of surgery. The authors recommend the use of pinless navigation to verify the coronal alignments of conventional cutting blocks in TKA before the bone cuts are made. LEVEL OF EVIDENCE: I.

Recovery in knee range of motion reaches a plateau by 12 months after total knee arthroplasty.

PURPOSE: The primary aim of this study was to identify the time point at which improvements in knee range of motion reach a plateau, if any. The secondary aim of this study was to investigate the correlation between the improvements in knee range of motion and patient-reported outcomes [Oxford knee score (OKS) and SF-36]. The hypothesis is that there is a time point at which the recovery in the knee range of motion after total knee arthroplasty (TKA) plateaus. METHOD: A prospective study of 145 patients who underwent TKA was conducted. All TKAs were performed by the same surgeon. OKS and SF-36 scores were measured preoperatively and at 6, 12, and 24 months. Range of motion was measured preoperatively and at 1, 3, 6, 12, and 24 months postoperatively. RESULTS: This study shows that for surgeon/therapist reported range of motion, a plateau in recovery was reached at 12 months after TKA. It was also found that range of extension is significantly correlated with OKS, whereas range of flexion was not significantly correlated with OKS. CONCLUSIONS: Knowledge of when patients fully recover after TKA will allow appropriate counseling of patients during preoperative consultation. Also, this knowledge will enable surgeons/therapists to better monitor the rehabilitation progress of TKA patients, and make adjustments to the rehabilitation protocol. In addition, our study shows that objective surgeon-/therapist-measured outcome (range of motion) has a significant correlation with subjective patient-reported outcomes (OKS). Hence, both outcome measures should be employed in the postoperative monitoring of patient progress. LEVEL OF EVIDENCE: Prospective case series, Level IV.

Functional Outcome and Quality of Life after Patient-Specific Instrumentation in Total Knee Arthroplasty.

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.