Complication Rates Are Not Higher After Outpatient Versus Inpatient Fast-Track Total Knee Arthroplasty: A Propensity-Matched Prospective Comparative Study.

BACKGROUND: This prospective study aimed to compare the complication rates and clinical outcomes of propensity-matched patients who received fast-track total knee arthroplasty (FT TKA) in outpatient versus inpatient settings. METHODS: Patients (n = 629) who received FT TKA at various outpatient (n = 176) and inpatient (n = 462) surgery rates were prospectively followed until 90 days after surgery. The decision between inpatient versus outpatient FT TKA was made on a case-by-case basis, depending on consultation between the surgeon and patient. Complications were collected to distinguish between intraoperative complications, complications with no readmission, complications with readmission, and complications with reoperation. Propensity scores based on age, sex, body mass index, and the American Society of Anesthesiologists score were used to match outpatient to inpatient FT TKA. A cumulative incidence function was computed by taking the time to diagnose any postoperative complication in the first 90 days as the end point. RESULTS: Propensity score matching (1:2 ratio) for comparison resulted in 173 outpatient FT TKAs and 316 inpatient FT TKAs. No significant differences were observed between outpatient versus inpatient FT TKA for intraoperative complication rates (2% in both groups). At 90-day follow-up, no significant differences were observed between outpatient versus inpatient FT TKA for total complications with no readmission (8.0 versus 7.9%), complications with readmission but no reoperation (1.1 versus 0.6%), and complications with reoperation (4.0 versus 4.4%). A comparison of postoperative complication diagnosis time using the cumulative incidence function revealed no significant differences between outpatient versus inpatient FT TKA. CONCLUSIONS: The present study revealed that there were no differences in 90-day postoperative complication rates between outpatient and inpatient FT TKA and that there were also no differences in rates of intraoperative complications, readmissions, or reoperations. These findings may encourage hesitant surgeons to move toward outpatient TKA pathways, as there is no greater risk of early postoperative complications that could be more difficult to manage after discharge. LEVEL OF EVIDENCE: Level II.

The coronal plane alignment of the knee classification does not correlate with the functional knee phenotype classification.

PURPOSE: It is now well established that the coronal anatomy of the lower limb is highly variable both in non-arthritic subjects and subjects undergoing total knee arthroplasty (TKA). Two new classifications were recently described independently, but never compared: functional knee phenotypes classification and coronal plane alignment of the knee (CPAK) classification. The hypothesis of this study was that there was a significant difference between the values of the hip-knee-ankle angle (HKA) and the arithmetic hip-knee-ankle angle (aHKA) measures in the same patient at the time of TKA. METHODS: Five hundred and twenty cases were randomly selected among patients operated on for a TKA with navigation assistance. Anatomical parameters were collected during surgery by a navigation system, and the corresponding data of the CPAK classification were calculated. The numerical values of measured HKA and aHKA in the same patient were compared. RESULTS: The measured HKA had a mean of 3.0° varus (standard deviation of 6.0°). The calculated aHKA had a mean of 1.8° varus (standard deviation 4.8°). There was a significant difference between the values of the two measurements in the same subject (p = 0.005) and a weak negative correlation between the values of the two measurements in the same subject. In addition, there was no relationship between HKA values and joint line obliquity values or CPAK class. CONCLUSION: A significant difference and a weak correlation between the values of the HKA and aHKA measures in the same subject were observed. The two analysis techniques used provide different information, and their correlation is only partial. These two techniques therefore appear to be complementary rather than exclusive. The clinical relevance of using these techniques during TKA remains unknown. LEVEL OF EVIDENCE: III.

The coronal alignment technique impacts deviation from native knee anatomy after total knee arthroplasty.

PURPOSE: The aim of this study was to analyze and quantify the changes in native coronal alignment of a population of TKA patients according to different alignment goals. METHODS: Five hundred and twenty TKAs were analyzed. The following angles were measured using an image-free navigation system prior to prosthetic implantation: medial femorotibial mechanical angle without stress and with maximum manual stress to reduce the deformity, medial distal femoral mechanical angle, medial proximal tibial mechanical angle. The native angles were derived from the osteoarthritic knee angles using a validated correction technique, and the overall, femoral and tibial coronal phenotypes were defined. Five different coronal alignment techniques were simulated: mechanical (MA), restricted mechanical (RMA), anatomical (AA), kinematic (KA) and restricted kinematic (RKA). The overall, femoral and tibial coronal phenotypes were compared before and after TKA. The primary endpoint was the binary criterion of whether or not TKA restored the natural overall phenotype. Secondary endpoints were the binary criteria of whether or not the natural femoral and tibial phenotypes were restored by TKA. The rates of restored and non restored phenotypes were compared with a Chi-square test at a 0.05 level of significance, with post hoc tests between all pairs of techniques at a 0.01 level of significance. RESULTS: The overall phenotype was restored significantly differently by the five alignment techniques: 15% for MA, 23% for RMA, 2% for AA, 100% for KA and 79% for RKA (p < 0.001). There was a significant difference between each of the technique pairs (p < 0.01 to p < 0.001), except for the mechanical alignment-restricted mechanical alignment pair. The femoral phenotype was restored significantly differently by the five alignment techniques: 37% for MA, 58% for RMA, 19% for AA, 100% for KA and 85% for RKA (p < 0.001). The tibial phenotype was restored significantly differently by the five alignment techniques: 36% for MA, 36% for RMA, 17% for AA, 100% for KA and 88% for RKA (p < 0.001). There was a significant difference between each pair of techniques for both femoral and tibial phenotypes (p < 0.01 to p < 0.001). CONCLUSION: Except for the kinematic alignment technique, the various alignment techniques induce significant changes in the pre-arthritic anatomy of the TKA patient. The surgeon must be aware of these modifications. The clinical relevance of this alteration still needs to be defined. LEVEL OF EVIDENCE: III.

Accuracy of the correction achieved after a valgus high tibial osteotomy: Comparison of the Hernigou table and navigation.

INTRODUCTION: The outcome of a medial opening wedge valgus high tibial osteotomy indicated for the treatment of isolated medial tibiofemoral osteoarthritis depends mainly on the accuracy of the correction of the hip-knee-ankle angle (HKAA) and the mechanical medial proximal tibial angle (mMPTA). Most authors aim for a desired correction target between 2° and 4° of valgus. Several planning and surgical techniques have been described to achieve this target value that is specific to each surgeon. OBJECTIVE: The purpose of this study was to compare the accuracy of the correction achieved using either the Hernigou table (HT) planning method or a computer-assisted navigation system (CAS). It was hypothesized that no difference would be found between these 2 techniques. MATERIALS AND METHODS: This retrospective single-center study involved 43 knees: 21 in the HT group and 22 in the CAS group. Two surgeons (ME, JYJ), who were experts in 1 of the 2 planning methods performed these procedures, with a single surgeon assigned to each group. The correction was noted in the operative report and was considered to be the desired correction target. The surgical correction was calculated by comparing preoperative and immediate postoperative mMPTA measurements. The surgical accuracy, where a value close to 0 represented optimal accuracy, was defined as the absolute value of the difference between the correction target set by the surgeon and the surgical correction achieved. The median accuracy between the 2 groups was compared by a Mann-Whitney U test (significance level at 5%). The number of patients deviating from the target by>3° was analyzed with a Fisher exact test (significance level at 5%). Pre- and postoperative comparisons of the HKAA measurements could not be used because the measurement was not performed postoperatively for the CAS group. RESULTS: The median surgical accuracy on the mMPTA was 1.4° (0-4.1) for the HT group versus 1.9° (0.2-6.7) for the CAS group (p=0.85). Sixteen procedures (76%) were performed with an accuracy of<3° in the HT group versus 15 in the CAS group (68%) (p=0.73). DISCUSSION-CONCLUSION: The working hypothesis was confirmed: no differences were found between the HT and CAS groups regarding the surgical accuracy in achieving the corrections set in this series. We therefore demonstrated that HT was a highly accessible, simple and reliable technique for achieving the planned target. It can be used widely. LEVEL OF EVIDENCE: III; comparative retrospective series.

Complications of total hip or knee arthroplasty are not significantly more common after ambulatory surgery than after in-patient surgery and enhanced recovery: A case-control study with propensity-score matching.

BACKGROUND: Reluctance to perform total hip arthroplasty (THA) and total knee arthroplasty (TKA) on an ambulatory basis stems from concern that complications might be more common than with enhanced recovery after surgery (ERAS). The objective of this study was to compare the risks of complications, readmission, and reoperation with these two strategies. HYPOTHESIS: The complication rate is significantly higher after ambulatory surgery (AS) than with ERAS. MATERIAL AND METHODS: Consecutive patients who underwent primary unilateral THA or TKA by two senior surgeons to treat a non-traumatic condition between July 2016 and December 2019 were eligible. We developed a propensity score, which we used to individually match each of the 91 patients managed by AS to the 91 patients managed with ERAS (control group). Follow-up was 3 months. The primary outcome was development of a complication within the first 3 months. Secondary outcomes were complication severity as classified according to Clavien-Dindo, re-admissions within 3 months, and re-operations within 3 months. RESULTS: Complications were not significantly more common after AS than with ERAS (15% and 11%, respectively, p=0.38). No significant differences were found between the two groups for complication severity (2.9±0.5 versus 2.6±0.8), proportion of re-admitted patients (14% versus 9%), or proportion of re-operated patients (14% versus 9%). DISCUSSION: The risk of complications was not higher after AS than with ERAS. Reluctance to perform AS due to concern about safety does not seem justified by the evidence. LEVEL OF EVIDENCE: III, propensity score-matched case-control study.

Functional knee phenotypes of OA patients undergoing total knee arthroplasty are significantly more varus or valgus than in a non-OA control group.

PURPOSE: The aim of this study was to analyse the coronal alignment of a large population of patients undergoing total knee arthroplasty using a modern classification of the knee phenotypes found in a population of non-osteoarthritic individuals. METHODS: Five hundred and four navigated total knee arthroplasties were included in the OA group. The following angles were measured with a computer image-free navigation system: mechanical femorotibial angle measured on the medial side without stress and with maximum manual stress to reduce deformation, and medial distal femoral mechanical angle. The native medial distal femoral and medial proximal tibial angles (coronal orientation of the femoral or tibial joint line after correction of wear) were calculated. The data were analysed as categorical data. These data were then compared with those published in a non-arthritic population, considered as a control non-OA group. The main criterion was the percentage of subjects with normal overall coronal alignment, defined by the association of a normal native medial distal femoral angle and a normal native medial proximal tibial angle. The secondary criteria were the percentages of subjects with normal medial femorotibial mechanical angle, normal native medial distal femoral angle and normal native medial proximal tibial angle. The influence of gender on primary and secondary criteria in the study group was analysed. The most frequent phenotypes in the study group were identified. RESULTS: Normal overall coronal alignment was found in 66 patients in the OA group (12.7%) and 76 patients in the non-OA-group (24.7%) (p < 0.01 after adjustment by gender). There were fewer normal patients in the OA-group than in the non-OA-group for medial femorotibial mechanical angle, native medial distal femoral angle and native medial proximal tibial angle. In females, there were significantly fewer normal medial femorotibial mechanical angle. In males, there were significantly more cases with native medial distal femoral varus and in females more cases with native medial distal femoral valgus. There was no significant influence of gender on native medial proximal tibial angle. There was a wider distribution of the phenotypes in the OA-group than in the non-OA-group. CONCLUSION: The distribution of functional phenotypes of the knee in patients undergoing total knee arthroplasty is different from those found in a reference non-osteoarthritic population. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

Cement Loaded With High-Dose Gentamicin and Clindamycin Reduces the Risk of Subsequent Infection After One-Stage Hip or Knee Arthroplasty Exchange for Periprosthetic Infection: A Preliminary Study.

BACKGROUND: The use of antibiotic-loaded acrylic cement for treating periprosthetic joint infections remains controversial. We hypothesized that the raw rate of surgical site infection (SSI) is lower after using cement loaded with high-dose gentamicin and clindamycin than after using cement loaded with standard-dose gentamicin for implant fixation during 1-stage hip and knee revision arthroplasty for infection. METHODS: One hundred seventy-one continuous patients operated by 2 experienced surgeons during a 2-year period were included in the study. All patients were followed for 24 months. The primary endpoint was the raw rate of SSI after 2 years of follow-up time. RESULTS: The raw rate of SSI after 2 years of follow-up time was significantly lower in the study group (13%) than in the control group (26%) (P = .03) with an odds ratio of 0.42 (P = .03). These SSIs were new infections rather than a recurrence/persistence of the initial infection. CONCLUSION: The cement used in the study group significantly reduced the risk of SSI relative to the cement used in the control group. Routine use of this high-dose dual antibiotic-loaded cement can be considered during 1-stage knee or hip revision arthroplasty for infection.

Navigation Improves the Survival Rate of Mobile-Bearing Total Knee Arthroplasty by Severe Preoperative Coronal Deformity: A Propensity Matched Case-Control Comparative Study.

The primary hypothesis of this study was that the survival rate over 10 years of total knee arthroplasties (TKAs) implanted with a navigation system was superior to that of TKAs implanted with a conventional technique. The secondary hypothesis was that the severity of the initial coronal deformity had a negative influence on the survival rate. A national, multicentric, retrospective study was performed in France, including eight university or private centers with high volumes in knee surgery. Cases operated on with either a conventional (control group) or a navigated (study group) technique were matched after calculating the propensity score using the logistic regression technique. All patients were contacted after 10 years or more to determine the survival of the TKA. The need for date and cause of revision were noted. The primary end point of the study was the occurrence of a revision for any mechanical reason. Survival curves were calculated using the Kaplan-Meier's technique, with the primary criterion as end point. The influence of the implantation technique was analyzed by a log-rank test at a 5% level of significance. The influence of severity of the preoperative coronal deformity was analyzed using the same technique. A total of 513 cases were included in each group. The survival rates after 13 years were 96.5% in the study group and 92.9% in the control group (not significant). There was no significant difference between both groups for the survival rates after 13 years for small deformity (96.0 vs. 97.0%), but the difference was significant for large deformity (97.0 vs. 89.0%, p = 0.04). The results suggest that the use of a navigation system, allowing a more consistent correction of the preoperative coronal deformity, thus allows a better long-term prosthetic survival in cases with a large initial coronal deformity. A navigation system should be routinely used in cases of initial coronal deformity greater than or equal to 10 degrees, as conventional techniques do not routinely provide satisfactory axial correction in these difficult cases.

No difference in 13-year survival after medial pivot or central pivot mobile bearing total knee arthroplasty. A propensity matched comparative analysis.

PURPOSE: The present study was designed to evaluate the long-term results (more than 10 years) of mobile bearing total knee arthroplasty (TKA) and to compare the survival of medial pivot axis (MPA) and central pivot axis (CPA) TKAs. The primary hypothesis was that the 10- to 15-year survival rate of MPA TKAs will be better than CPA TKAs. METHODS: A national, multicenter, retrospective study was performed in France. In this case-control design, 1154 TKAs were paired into the CPA group (control group: 577 cases) and MPA group (study group: 577 cases) based on a logistic regression analysis of age, gender, body mass index and severity of the coronal deformity, defining the propensity score for each case. Final survival information follow-up was obtained for 946 cases (82%). RESULTS: There was no significant difference between the control and study groups for any baseline data. Twenty-two prosthetic revisions (2%) were performed for mechanical reasons during the follow-up period. There was no significant difference between the 13-year survival rates of CPA (98%) and MPA (97%) TKAs. There was no significant difference between groups in their final Oxford and Knee Society scores. CONCLUSION: Our findings do not support the assumption that medialization of the pivot axis of a mobile bearing TKA improves clinical results or survival. LEVEL OF EVIDENCE: Level III.

Fast-track procedures after primary total knee arthroplasty reduce hospital stay by unselected patients: a prospective national multi-centre study.

PURPOSE: The aim of this study was to evaluate the impact of fast-track procedures (FTPs) on length of hospital stay after primary total knee arthroplasty (TKA) in a prospective, national, multicentric analysis. The innovative point was that no patient selection was used. The hypothesis was that FTPs reduce hospital stay after primary TKA for non-traumatic conditions compared with the national database. METHODS: An observational prospective study was conducted in ten centres throughout France. A total of 839 patients included in FTPs were followed up for three months. The average LOS, direct return home rate, unscheduled re-admission rate, and re-intervention rate were compared with those in the national database (93,329 TKAs). Knee society and Oxford score were collected. RESULTS: The mean LOS was 4.4 ± 3.3 days, while the national base LOS was 6.4 ± 3.1 days (p < 0.001). A total of 560 patients (66.7%) were able to return home, compared with 47,617 (49.6%) in the national database (p < 0.001). Thirty-five patients (4.2%) were re-admitted within 90 days of the intervention, compared with 10,399 (10.8%) in the national database (p < 0.001). Seventeen patients (2.0%) were re-operated upon within 90 days after the TKA, compared with 529 (0.5%) in the national database (p < 0.05). CONCLUSION: The FTPs used by unselected patients allowed a significant decrease in the mean LOS and in the rate of re-admission and a significant increase of the rate of direct home return after primary TKA compared with the national database. The significant increase in the re-operation rate warrants further investigation. However, FTP should become the standard of care after this intervention.

Bleeding and thromboembolism risk of standard antithrombotic prophylaxis after hip or knee replacement within an enhanced recovery program.

INTRODUCTION: Prevention of venous thromboembolism (VTE) generally consists of low molecular weight heparin (LMWH) or direct oral anticoagulants (DOACs) after total hip arthroplasty (THA) or total knee arthroplasty (TKA). Enhanced recovery after surgery (ERAS) protocols may reduce the VTE risk after these procedures. The aim of this study was to compare the risk of VTE and the risk of bleeding complications in a non-selected population of primary THA and TKA cases done within an ERAS protocol. HYPOTHESIS: The risk of postoperative VTE after primary THA and TKA is lower than the risk of bleeding complications within an ERAS protocol. METHODS: This was a prospective observational study conducted on a national scale in France. All patients who underwent primary unilateral THA or TKA at one of 11 participating hospitals between October 2016 and October 2017 were enrolled and followed for 3 months. The occurrence of a VTE or major bleeding event was recorded. No patients were lost to follow-up at 3 months. RESULTS: Of the 1110 THA cases, there were 5 VTE (0.4%) and 19 bleeding events (1.7%). Of the 893 TKA cases, there were 9 VTE (1.0%) and 14 bleeding events (1.7%). There was no significant difference in the VTE incidence and bleeding event incidence after THA and TKA. The overall incidence of bleeding complications (1.7%) was significantly greater than the overall incidence of VTE complications (0.7%) (p=0.005). This was the case after THA (p=0.004) but not after TKA. DISCUSSION: The primary finding of this study is that bleeding complications are significantly more common than VTE complications after THA or TKA within an ERAS protocol. Based on these findings, the cost-benefit ratio of antithrombotic prophylaxis by LMWH or DOACs in this context should be reassessed. LEVEL OF EVIDENCE: IV; Prospective cohort study without control group.