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.

Cement loaded with high-dose gentamicin and clindamycin does not reduce the risk of subsequent infection after aseptic total hip or knee revision arthroplasty: a preliminary study.

PURPOSE: The aim of this study was to quantify the prophylactic effect of high-dose gentamicin and clindamycin antibiotic-loaded bone cement (ALBC) during revision total hip (rTHA) or knee (rTKA) arthroplasty for aseptic reasons. The hypothesis was that the raw surgical site infection (SSI) rate is lower when this particular cement is used in comparison with cement loaded with standard-dose gentamicin during rTHA or rTKA for aseptic reasons. METHODS: This retrospective study included 290 consecutive patients undergoing aseptic rTHA or rTKA. Two consecutive cohorts were defined: the first (control group) involved 145 patients where ALBC with gentamicin only was used; the second (study group) involved 145 patients where ALBC with high-dose gentamicin and clindamycin was used. The primary endpoint was the raw SSI rate after 24 months. RESULTS: The raw SSI rate was 8/145 (6%) in the control group and 13/145 (9%) in the study group (odds ratio 0.62, p = 0.26). There was a significant impact of the presence of any risk factor on the SSI rate (15/100 versus 6/169, odds ratio = 4.25, p = 0.002), but no significant impact of any individual risk factor. No complication or side effect related to ALBC was observed in either group. CONCLUSION: These results do not support the routine use of gentamicin and clindamycin ALBC for fixation of revision implants after rTHA and rTKA for aseptic reasons.

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.

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.

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.

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.

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.

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.

No Detectable Polyethylene Wear 15 Years After Implantation of a Mobile-Bearing Total Knee Arthroplasty With Electron Beam-Irradiated Polyethylene.

BACKGROUND: The present study was designed to evaluate the risk of significant polyethylene (PE) wear 10 years or more after implantation of a total knee arthroplasty (TKA) using electron beam-irradiated highly cross-linked PE component. METHODS: All patients operated between 2001 and 2004 for implantation of this particular TKA in the two participating centers were eligible for this study. All patients were contacted after the 10-year follow-up for repeat clinical examination and radiological evaluation. The occurrence of a revision prior to the final evaluation and its reason were recorded. The thickness of the PE piece was measured on plain X-rays. RESULTS: Five hundred seventy-eight TKAs were implanted during the study time-frame. One hundred sixteen patients deceased prior to the 10-year follow-up (20%). An additional 121 patients were lost to follow-up prior to the 10-year follow-up (21%). Complete follow-up at 10 years or more (including death or revision) was obtained for 448 cases (78%). Ten prosthetic revisions were performed for mechanical reasons during the follow-up time (2%). One single revision was performed because PE wear after 13 years. No significant PE wear was detected at the final radiographic evaluation for nonrevised cases. The 10-year survival rate for mechanical revision only was 98.0% and decreased to 96.2% at 15 years. CONCLUSION: The use of electron beam-irradiated PE was associated with an extremely low incidence of wear. This technology may be considered as safe regarding PE behavior for TKA after more than 10 years. Further improvement of PE manufacturing may be not required.

Noninvasive navigated assessment of the lower limb axis prior to knee arthroplasty: a feasibility study.

The purpose of the study was to assess accuracy and repeatability of a noninvasive navigated (NIN) measurement of the lower limb axes by comparison with the conventional, invasive navigated (IN) technique. The tested hypothesis was that NIN measure will significantly differ from IN measure when performed on a supine patient under general anesthesia just prior to knee arthroplasty. The accuracy study involved 20 cases. The following measures were performed with both systems: maximal extension angle, coronal mechanical femoro-tibial angle at the previously assessed maximal extension angle, coronal mechanical femoro-tibial angle at 30° of knee flexion. NIN and IN measures were compared with the appropriate statistical tests. The repeatability study involved 14 cases. The same measures were performed with the NIN system twice by two independent observers. The intra- and inter-observer variability was assessed by the calculation of the intra-class correlation coefficient. After correction for the systematic biases, the differences between the two systems were not significant. A good correlation, a good coherence and an excellent agreement between NIN and IN measures of maximal extension angle and coronal femoro-tibial mechanical angle at maximal extension. But measures at 30° of flexion were inconsistent. The NIN system can be considered as an accurate and precise tool for the assessment of the knee extension angle and the coronal deformation at maximal extension prior to knee arthroplasty. But this system is less accurate and less repeatable when measuring coronal femoro-tibial mechanical angle at 30° of flexion and should not be used for this purpose.

One- and two-stage surgical revision of peri-prosthetic joint infection of the hip: a pooled individual participant data analysis of 44 cohort studies.

One-stage and two-stage revision strategies are the two main options for treating established chronic peri-prosthetic joint infection (PJI) of the hip; however, there is uncertainty regarding which is the best treatment option. We aimed to compare the risk of re-infection between the two revision strategies using pooled individual participant data (IPD). Observational cohort studies with PJI of the hip treated exclusively by one- or two-stage revision and reporting re-infection outcomes were retrieved by searching MEDLINE, EMBASE, Web of Science, The Cochrane Library, and the WHO International Clinical Trials Registry Platform; as well as email contact with investigators. We analysed IPD of 1856 participants with PJI of the hip from 44 cohorts across four continents. The primary outcome was re-infection (recurrence of infection by the same organism(s) and/or re-infection with a new organism(s)). Hazard ratios (HRs) for re-infection were calculated using Cox proportional frailty hazards models. After a median follow-up of 3.7 years, 222 re-infections were recorded. Re-infection rates per 1000 person-years of follow-up were 16.8 (95% CI 13.6-20.7) and 32.3 (95% CI 27.3-38.3) for one-stage and two-stage strategies respectively. The age- and sex-adjusted HR of re-infection for two-stage revision was 1.70 (0.58-5.00) when compared with one-stage revision. The association remained consistently absent after further adjustment for potential confounders. The HRs did not vary importantly in clinically relevant subgroups. Analysis of pooled individual patient data suggest that a one-stage revision strategy may be as effective as a two-stage revision strategy in treating PJI of the hip.

European guidelines on perioperative venous thromboembolism prophylaxis: Aspirin.

: There is a good rationale for the use of aspirin in venous thromboembolism prophylaxis in some orthopaedic procedures, as already proposed by the 9th American College of Chest Physicians' guidelines (Grade 1C). We recommend using aspirin, considering that it may be less effective than or as effective as low molecular weight heparin for prevention of deep vein thrombosis and pulmonary embolism after total hip arthroplasty, total knee arthroplasty and hip fracture surgery (Grade 1C). Aspirin may be less effective than or as effective as low molecular weight heparins for prevention of deep vein thrombosis and pulmonary embolism after other orthopaedic procedures (Grade 2C). Aspirin may be associated with a low rate of bleeding after total hip arthroplasty, total knee arthroplasty and hip fracture surgery (Grade 1B). Aspirin may be associated with less bleeding after total hip arthroplasty, total knee arthroplasty and hip fracture surgery than other pharmacological agents (Grade 1B). No data are available for other orthopaedic procedures. We do not recommend aspirin as thromboprophylaxis in general surgery (Grade 1C). However, this type of prophylaxis could be interesting especially in low-income countries (Grade 2C) and adequate large-scale trials with proper study designs should be carried out (Grade 1C).

European guidelines on perioperative venous thromboembolism prophylaxis: Day surgery and fast-track surgery.

: In recent years, day surgery and fast-track surgery have experienced a continuous increase in volume. Many procedures are now performed on an outpatient protocol, including general, orthopaedic, oncological, reconstructive or vascular surgery. The management of these patients is safe, but the incidence of venous thromboembolism in this population remains unknown. Several risk factors can be identified and stratified derived from studies of inpatient surgical management (e.g. Caprini score). Recommendations for thromboprophylaxis should be tailored from the assessment of both personal and procedure-related risk factors, although with a lack of evidence for application in outpatient management. For patients undergoing a low-risk procedure without additional risk factors, we recommend only general measures of thromboprophylaxis (early ambulation, optimal hydration) (Grade 1B). For patients undergoing a low-risk procedure with additional risk factors, or a high-risk procedure without additional risk factors, we recommend general measures of thromboprophylaxis (Grade 1B) and we suggest the administration of pharmacological prophylaxis with low molecular weight heparins (Grade 2B). For patients undergoing a high-risk procedure with additional risk factors we recommend general measures of thromboprophylaxis (Grade 1B) and pharmacological prophylaxis with low molecular weight heparins over other drugs (Grade 1B), or suggest specific mechanical measures in case of increased bleeding risk (Grade 2C). Pharmacological prophylaxis should last a minimum of 7 days (Grade 1B), although in selected cases of fast-track surgery, thromboprophylaxis could be limited to hospitalisation only (Grade 2C) and in specific cases of high-risk procedures, thromboprophylaxis could be extended for up to 4 weeks (Grade 2B).

Posterior tibial slope impacts intraoperatively measured mid-flexion anteroposterior kinematics during cruciate-retaining total knee arthroplasty.

PURPOSE: Posterior tibial slope (PTS) for cruciate-retaining (CR) total knee arthroplasty (TKA) is usually pre-determined by the surgeon. Limited information is available comparing different choices of PTS on the kinematics of the CR TKA, independent of the balancing of the extension gap. This study hypothesized that with the same balanced extension gap, the choice of PTS significantly impacts the intraoperatively measured kinematics of CR TKA. METHODS: Navigated CR TKAs were performed on seven fresh-frozen cadavers with healthy knees and intact posterior cruciate ligament (PCL). A custom designed tibial baseplate was implanted to allow in situ modification of the PTS, which altered the flexion gap but maintained the extension gap. Knee kinematics were measured by performing passive range of motion (ROM) tests from full extension to 120° of flexion on the intact knee and CR TKAs with four different PTSs (1°, 4°, 7°, and 10°). The measured kinematics were compared across test conditions to assess the impact of PTS. RESULTS: With a consistent extension gap, the change of PTS had significant impact on the anteroposterior (AP) kinematics of the CR TKA knees in mid-flexion range (45°-90°), but not so much for the high-flexion range (90°-120°). No considerable impacts were found on internal/external (I/E) rotation and hip-knee-ankle (HKA) angle. However, the findings on the individual basis suggested the impact of PTS on I/E rotation and HKA angle may be patient-specific. CONCLUSIONS: The data suggested that the choice of PTS had the greatest impact on the mid-flexion AP translation among the intraoperatively measured kinematics. This impact may be considered while making surgical decisions in the context of AP kinematics. When using a tibial component designed with "center" pivoting PTS, a surgeon may be able to fine tune the PTS to achieve proper mid-flexion AP stability.

Minimally invasive unicompartmental knee arthroplasty.

The exact indication for a unicompartmental knee arthroplasty (UKA) remains debated. Minimally invasive techniques have been developed to decrease the surgical trauma related to the prosthesis implantation, and this technique is well fitted to UKA. However, there are concerns about loss of accuracy with minimally invasive techniques. Furthermore, rapid recovery techniques have been developed in order to reduce the length of hospital stay. Again, UKA is well fitted to these new developments of postoperative care. We combine routinely a minimal invasive operative technique with navigation assistance to ensure proper positioning of the implants as well as an optimal ligamentous balance. Instruments have been adapted for use with a typical 6-cm skin incision with little change from the conventional navigated operating technique. A multimodal pain treatment is implemented immediately after the implantation, with special attention to a routine saphenous nerve blockade. Patients are instructed to stand up on the day of surgery with full weight bearing and to mobilize the knee joint without restriction. They may be discharged at least on the day following surgery, and the most favorable patients may be operated in our day-case surgery unit. These conclusions should be confirmed on a larger scale.

Minimal influence of the anterolateral knee ligament on anterior and rotational laxity of the knee: a cadaveric study.

Knee laxity may be impacted by rupture of the anterolateral knee ligament (ALL). The goal of this study was to measure tibial translation and rotation as a function of the status of the ALL and the anterior cruciate ligament (ACL). Five pairs of fresh frozen cadaver specimens were analyzed. The knee was positioned in 20° flexion. Calibrated posteroanterior forces and internal/external torques were successively applied. Anterior tibial translation and total internal/external tibial rotation were measured with a navigation system. Three conditions were used in each knee: intact ACL and ALL, transection of ACL or ALL (randomly assigned to each knee of a pair), and transection of both ligaments. The primary outcome criterion was the increase in tibial rotation at 8 Nm. The mean increase in tibial rotation at 8 Nm was 0.8° after transecting the ALL only, 1.2° after transecting the ACL only, and 0.8° after transecting both ligaments. The mean increase in anterior tibial translation at 250 N was 1.2 mm after transecting the ALL only, 9.0 mm after transecting the ACL only, and 6.1 mm after transecting both ligaments. There was no significant increase in the tibial rotation or anterior tibial translation after transecting the ALL only or after transecting the ALL in ACL-deficient knees. The expected role of ALL in controlling anterior or rotational tibia motion could not be confirmed.