Morel-Lavallée lesion around the knee successfully treated with video-assisted endoscopic débridement: A case report.

We report a chronic Morel-Lavallée lesion around the knee in a competitive high schooler softball player, successfully treated with video-assisted endoscopic debridement. Endoscopic surgery is a viable option to treat Morel-Lavallée lesions in active patients who seek a rapid return to sport. The potential advantages of an endoscopic treatment would be a faster healing process and an earlier return to motion and function due to a less morbid and more cosmetic surgical approach.

Effect of Antibiotic Prophylaxis on Infection Rates in Pediatric Supracondylar Humerus Fractures Treated with Closed Reduction and Percutaneous Pinning: A Prospective Double-Blinded Randomized Controlled Trial.

BACKGROUND: Supracondylar humerus fractures (SCHFs) are the most common elbow fracture in the pediatric population. In the case of displaced fractures, closed reduction and percutaneous Kirschner wire pinning (CRPP) is commonly performed. Infection rates are between 0 and 7%; however, retrospective studies have shown no benefit of preoperative antibiotics. There continues to be notable variability in antibiotic usage based on surgeon preference and local institutional policy. We conducted a double-blinded, randomized controlled trial to evaluate whether antibiotic prophylaxis reduces the risk of infection in pediatric SCHF patients treated with CRPP. METHODS: Pediatric patients with displaced SCHF who presented to a pediatric hospital were enrolled and randomized into two groups. Group I received one dose of prophylactic antibiotics (25 mg/kg cefazolin IV up to 1g or clindamycin 10 mg/kg up to 600 mg/kg IV in the case of cefazolin allergy). Group II received placebo (10-mL prefilled syringe of normal saline). All patients underwent CRPP and casting followed by pin removal 3 to 6 weeks after the initial procedure. The presence of pin-site infection, erythema, drainage, septic arthritis, and osteomyelitis was recorded. RESULTS: One hundred sixty patients were enrolled in the study. Eighty-two patients were randomized to receive antibiotics, and 78 patients were randomized to placebo. No difference was seen in the rate of infection between the treatment groups (1.2% in the antibiotic group versus 1.3% in the placebo group; P = 1.00). Presence of purulent drainage (0.0% versus 1.3%; P = 0.49), septic arthritis (0.0% versus 0.0%; P = 1.00), and osteomyelitis (1.2% versus 0.0%; P = 1.00) was similar in both groups. No difference in the need for additional antibiotics (1.2% versus 1.3%; P = 1.00) or additional surgery (1.2% versus 0.0%; P = 1.00) was found between groups. DISCUSSION: The use of antibiotic prophylaxis did not affect the risk of infection in pediatric patients who underwent CRPP for displaced SCHF. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT03261830. LEVEL OF EVIDENCE: Therapeutic Level I.

The Association of Sacro-Femoro-Pubic Angle and Postoperative Dislocation Following Total Hip Arthroplasty.

BACKGROUND: Spino-pelvic orientation may affect dislocation risk following total hip arthroplasty (THA). It can be measured on lateral lumbo-pelvic radiographs. The sacro-femoro-pubic (SFP) angle, measured on an antero-posterior (AP) pelvis radiograph, is a reliable proxy for pelvic tilt, a measurement of spino-pelvic orientation measured on a lateral lumbo-pelvic radiograph. The purpose of this study was to investigate the relationship between SFP angle and dislocation following THA. METHODS: An Institutional Review Board-approved retrospective case-control study was conducted at a single academic center. We matched 71 dislocators (cases) to 71 nondislocators (controls) following THA performed by 1 of 10 surgeons between September 2001 and December 2010. Two authors (readers) independently calculated SFP angle from single preoperative AP pelvis radiographs. Readers were blinded to cases and controls. Conditional logistic regressions were used to identify factors differentiating cases and controls. RESULTS: The data did not show a clinically relevant or statistically significant difference in SFP angles after adjusting for gender, American Society of Anesthesiologists classification, prosthetic head size, age at time of THA, measurement laterality, and surgeon. CONCLUSION: We did not find an association between preoperative SFP angle and dislocation following THA in our cohort. Based on our data, SFP angle as measured on a single AP pelvis radiograph should not be used to assess dislocation risk prior to THA.

Short-to Mid-Term Survivorship of a Patient-specific Unicompartmental Knee Arthroplasty Implant Cast from a Three-Dimensional Printed Mold.

The purpose of this study was to determine early survivorship and complication rates associated with the implantation of a new patient-specific unicompartmental knee implant cast from a three-dimensional (3D) printed mold, introduced in 2012. We retrospectively reviewed 92 consecutive patients who underwent unicompartmental knee arthroplasty (UKA) with a patient-specific implant cast from a 3D printed mold between September 2012 and October 2015. The early results of a patient-specific UKA implant were favorable in our cohort, with survivorship free from reoperation of 97% at an average 4.5 years follow-up. Future studies are necessary to investigate the long-term performance of this implant. Survivorship of a patient-specific unicompartmental knee arthroplasty implant cast from a 3D printed mold.

High Complication Rate Associated With Arthroscopic Lysis of Adhesions Versus Manipulation Under Anesthesia for Arthrofibrosis After Total Knee Arthroplasty.

BACKGROUND: Arthrofibrosis after total knee arthroplasty (TKA) is often treated by arthroscopic lysis of adhesions (ALAs) or manipulation under anesthesia (MUA). This study compared the 2-year complication rates of ALA and MUA and range-of-motion (ROM) outcomes for ALA, early MUA (<3 months after TKA), and delayed MUA (>3 months after TKA). METHODS: This retrospective cohort study included 425 patients undergoing ALA or MUA after primary TKA from 2001 to 2018. Demographics, clinical variables, and complication rates were collected from clinical records and compared using Student t -tests and Kaplan-Meier log-rank tests. Multivariable logistic regressions were used for adjusted analysis. ROM data were analyzed using fixed and mixed-effects models. RESULTS: ALA patients were younger (55.2 versus 58.9 years, P < 0.001) and underwent surgery later from the index TKA (12 versus 1.9 months, P < 0.001). The Charlson Comorbidity Index was higher in the MUA group. Preoperative ROM was significantly worse in the MUA cohort, but did not differ between groups after the procedure (117°, P = 0.27) or at 2 years. Demographics and ROM outcomes were equivalent between early MUA and delayed MUA ( P = 0.75). The incidence of repeat arthrofibrosis (7.1%) and revision arthroplasty (2.4%) was similar between ALA and MUA cohorts while ALA patients had significantly more surgical site infections (3.8%) compared with MUA patients (0.47%, P = 0.017). DISCUSSION: Equivalent ROM outcomes were seen between ALA, early MUA, and delayed MUA for the treatment of arthrofibrosis after TKA. However, this study demonstrated a markedly higher complication rate, particularly surgical site infection, after ALA, suggesting that MUA may be the preferred option for treating arthrofibrosis at both early and late time points.

Synovial Fluid and Serum Neutrophil-to-Lymphocyte Ratio: Novel Biomarkers for the Diagnosis and Prognosis of Native Septic Arthritis in Adults.

BACKGROUND: Septic arthritis (SA) is a musculoskeletal emergency for which prompt diagnosis and treatment are critical. However, traditional diagnostic criteria of a synovial fluid (SF) white blood-cell count (WBC) of >50,000 cells/mm 3 or >90% polymorphonuclear leukocytes (%PMN) are not particularly sensitive or specific for the diagnosis of SA. Furthermore, prognostic markers are lacking. The purposes of this study were to assess the discriminative ability of the SF neutrophil-to-lymphocyte ratio (NLR) in the diagnosis of SA and of the serum NLR in the prognosis of SA. METHODS: A multi-institution, retrospective study of 598 patients with native shoulder, hip, or knee SA in 2000 to 2018 was conducted. SF-NLR was calculated from the arthrocentesis cell count with differential. Receiver operating characteristic curves were analyzed, and the optimal threshold of SF-NLR for SA diagnosis was determined using the Youden index. Results were compared with traditional SF diagnostic criteria. Similar analyses assessed the association of serum NLR with 90-day treatment failure and mortality for the subset of patients with confirmed hip or knee SA and with serum complete blood-cell counts with differentials (n = 235). Results were compared with traditional serum prognostic markers (WBC, C-reactive protein [CRP], and erythrocyte sedimentation rate [ESR]). RESULTS: The SF-NLR (area under the receiver operating characteristic curve [AUC], 0.85 [95% confidence interval (CI), 0.82 to 0.88]) was significantly more accurate for an SA diagnosis than SF-WBC (AUC, 0.80 [95% CI, 0.76 to 0.83]; p = 0.002) and SF-%PMN (AUC, 0.81 [95% CI, 0.77 to 0.84]; p = 0.01). The optimal threshold of SF-NLR was 25 (78% sensitivity and 81% specificity), compared with >50,000 cells/mm 3 for SF-WBC (56% sensitivity and 80% specificity) and >90% for SF-%PMN (65% sensitivity and 78% specificity). Elevated serum NLR was independently associated with 90-day treatment failure (odds ratio [OR], 7.04 [95% CI, 3.78 to 13.14]; p < 0.001) and mortality (OR, 7.33 [95% CI, 2.00 to 26.92]; p = 0.003); elevated serum WBC and CRP were also associated with treatment failure, and WBC, CRP, and ESR were not associated with mortality. CONCLUSIONS: This study provides compelling data on the superior diagnostic and prognostic ability of serum NLR and SF-NLR for SA compared with current clinical standards. Given that this biomarker requires no additional cost or time to return than current laboratory tests already being performed, pending validation, it can readily be used to aid clinicians in the diagnosis and prognostication of SA. LEVEL OF EVIDENCE: Diagnostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Reliability and Reproducibility of Sacro-Femoro-Pubic Angle Measurements on Anteroposterior Pelvis Radiographs.

BACKGROUND: The sacro-femoro-pubic (SFP) angle is a surrogate measurement for pelvic tilt obtained on anteroposterior (AP) pelvis radiographs. It is unknown whether the SFP angle can be measured reliably by senior surgeons and trainees alike. METHODS: We conducted an intrareader and interreader reliability study using preoperative AP pelvis radiographs. Using our hospital electronic database, we randomly selected 31 subjects undergoing primary total hip arthroplasty. An attending orthopedic surgeon and two orthopedic surgery residents performed two separate SFP angle measurements for each subject. Intrareader and interreader agreement were measured using intraclass correlation coefficients (ICC). RESULTS: Pairwise intrareader and interreader ICCs ranged from 0.91 to 0.99. Overall ICC was 0.94. Interreader ICCs between the attending surgeon and each orthopedic resident were 0.93 and 0.98, and the ICC between orthopedic residents was 0.91. Interreader mean differences for SFP angle measurements were 2.32 degrees or less: -2.03 (standard deviation: 2.23) and 0.29 (1.64) between the attending surgeon and each orthopedic resident, and 2.32 (2.44) between orthopedic residents. CONCLUSION: SFP angle may be measured reliably on AP pelvis radiographs by senior clinicians and trainees. SFP angle measurement may prove helpful as an alternative to pelvic tilt measurements when lateral pelvic radiographs are not available.

Preoperative Platelet and International Normalized Ratio Thresholds and Risk of Complications After Primary Hip Fracture Surgery.

BACKGROUND: A paucity of data exists on safe platelet and international normalized ratio (INR) thresholds for hip fracture surgery. Recent work has called into question the safety of preoperative INRs < 1.5 for total knee arthroplasty, and optimal platelet thresholds are unknown. The purpose of this study was to identify the risk of 30-day postoperative morbidity and mortality in patients with thrombocytopenia or elevated INRs undergoing hip fracture surgery. METHODS: The National Surgical Quality Improvement Program database was queried for patients undergoing surgical treatment of a native hip fracture from 2012 to 2017 (N = 86,850). Patient demographic, laboratory, and complication data were collected. Patients with preoperative platelet counts or INRs within one day of surgery were included for analysis. Preoperative platelet counts and INRs were divided into four groups (<50 k/µL, ≥50 k to 100 k/µL, ≥100 k to 150 k/µL, ≥150 k/µL, and ≤1.0, >1.0 to 1.5, >1.5 to 2.0, and >2.0, respectively). Multivariable logistic regressions were used to assess the independent association between platelet count and INR on bleeding complications requiring transfusion, wound complications, reoperations, readmissions, and deaths. RESULTS: A total of 72,306 and 56,027 patients were included for analysis of preoperative platelet and INR levels, respectively. In reference to platelet levels ≥150 k/µL, a notably increased risk of bleeding events was observed for patients with platelet counts ≥100 k to 150 k/µL (odds ratio [OR] 1.21, 95% confidence interval 1.15 to 1.27), ≥50 to 100 k/µL (OR 1.85, 1.69 to 2.03), and <50 k/µL (OR 1.60, 1.25 to 2.04). Decreasing platelet counts were associated with a stepwise increased risk of mortality from OR 1.12 (1.02 to 1.22) for platelet counts ≥100 k to 150 k/µL to OR 1.63 (1.41 to 1.90) and OR 1.59 (1.06 to 2.39) for platelet counts ≥50 k to 100 k/µL and <50 k/µL, respectively. Elevated INR was associated with an increased risk of reoperations, readmissions, and death (P < 0.001 for all), with largest effect sizes observed starting at INRs >1.5. DISCUSSION: The results of this study suggest that preoperative platelet thresholds of <100,000/µL and INR thresholds of 1.5 serve as an important risk factor for complications after hip fracture surgery. Future work is warranted to determine whether preoperative platelet transfusions and/or INR reversal will improve outcomes for these patients. LEVEL OF EVIDENCE: Prognostic Level III.

HIV-Positive Patients Are at Increased Risk of Venous Thromboembolism After Total Joint Replacement.

BACKGROUND: Antiretroviral therapy has improved the life expectancy of HIV patients, leading to an increase in total joint replacement for age-related osteoarthritis. HIV patients are inherently hypercoagulable at baseline. The goal of our study was to compare the incidence of venous thromboembolism (VTE) in HIV patients with HIV-negative controls after total joint replacement. METHODS: A multicenter, retrospective cohort study of 110 HIV patients (85 hips and 25 knees) and 240 HIV-negative controls (180 hips and 85 knees) between 2000 and 2018. Prophylactic anticoagulation was used in 98% of patients postoperatively-low-molecular weight heparin (73%), warfarin (19%), aspirin (6%), and clopidogrel (1%). RESULTS: The VTE rate was 3.6% in the HIV-positive group (2.5% total hip arthroplasty [THA] and 8.0% total knee arthroplasty [TKA]) and 0.4% in the control group (0% THA and 1.7% TKA). VTEs occurred at the median (interquartile range) time of 40 days (1 to 52) post-op in the HIV group and 3 days post-op in the one control. Multivariable logistic regression adjusting for sex, smoking, history of VTE, and joint replaced identified HIV as an independent predictor of VTE (odds ratio 10.9, 95% confidence interval 1.1 to 114.0, P = 0.046). All patients with VTE were treated with warfarin (5 to 9 months); two cases were complicated by hemarthrosis and excessive bleeding at the insulin injection site. CONCLUSION: We observed increased rates of symptomatic VTE in HIV patients after THA (2.5%) and TKA (8%) compared with HIV-negative control patients (0% and 1.7%, respectively). HIV positivity was identified as an independent predictor of perioperative VTE. Our data suggests that HIV patients may be at higher risk for post-op VTE than HIV-negative patients. Surgeons may want to consider the use of more potent anticoagulation (ie, warfarin or novel anticoagulants) for a longer duration in HIV-positive patients. However, further studies are necessary to form evidence-based guidelines regarding this practice. LEVEL OF EVIDENCE: Level III, prognostic.

Technology Applications for Arthroplasty: Moving the Field Forward?

Total joint arthroplasty (TJA) is one of the most performed and successful surgeries in the United States for advanced degenerative and inflammatory arthritis with most patients reporting excellent outcomes. However, a large number of patients are still dissatisfied following TJA. To improve outcomes, new technologies such as patient-specific instrumentation and custom implants; smart implant trials; radiologic, computer, and portable accelerometer-based navigation systems; and robotics have been developed. Their overall goals are to avoid the drawbacks of conventional arthroplasty surgery, to simplify the procedures, to improve the accuracy of surgical techniques, to improve outcomes, and to decrease costs. This chapter provides an overview of the current technologies and their applications in TJA.

Trends in the surgical treatment of pathological proximal femur fractures in the United States.

BACKGROUND AND OBJECTIVES: Large scale data on the treatment of pathologic proximal femur fractures (PPFFs) are lacking. The purpose of this study was to evaluate trends in patient demographics, complication rates, and relative utilization rates of various techniques associated with PPFFs. METHODS: The American College of Surgeons-National Surgical Quality Improvement Program (NSQIP) database was queried for PPFFs from 2009 to 2017. Patient demographics, 30-day complications, and utilization rates were recorded. Trends in these variables were determined over the study period. RESULTS: Most patient demographics did not change during the study period. There were no trends toward decreasing rates of major complications (P = .82), reoperations (P = .65), non-home discharges (P = .17), readmissions (P = .07), or deaths (P = .75); transfusion rates significantly decreased (P < .001). Rates of hemiarthroplasty decreased (P = .03) and rates of intramedullary nailing increased (P = .001). DISCUSSION: Despite advances in cancer therapeutics, the average PPFF patient has not significantly changed over the past decade. Similarly, most short-term outcomes after PPFF surgery have not improved, demonstrating a need for improved perioperative protocols. Finally, rates of IMN fixation are increasing while rates of HA are falling at NSQIP hospitals. Given that orthopedic oncologists favor endoprosthetic reconstruction in most cases, there may be a need for increased communication between orthopedic oncologists and other members of the orthopedic community treating PPFFs.

Short-Term Morbidity and Mortality After Hemiarthroplasty and Total Hip Arthroplasty for Pathologic Proximal Femur Fractures.

BACKGROUND: As oncology patients have increasing life expectancies, total hip arthroplasty (THA) may become an important treatment option for pathologic proximal femur fractures (PPFFs). Although THA and hemiarthroplasty (HA) have been compared for native hip fracture treatment, no data on short-term morbidity and mortality are available in the pathologic setting. The purpose of this study is to compare short-term morbidity and mortality of HA vs THA for PPFFs. METHODS: The National Surgical Quality Improvement Program database was queried from 2007 to 2017 for patients with PPFFs treated with HA or THA. Propensity-adjusted logistic regressions were implemented to compare 30-day morbidity and mortality between procedures. Backwards stepwise regression was then used to determine independent predictors of treatment with HA compared to THA. RESULTS: In adjusted analysis, THA was associated with longer operative times (120.3 ± 5.6 vs 98.7 ± 4.9 minutes, P < .001); however, there were no differences between THA and HA with regard to 30-day rates of major complications (P = .3), minor complications (P = .77), reoperations (P = .99), readmissions (P = .35), or deaths (P = .63). Older age (P < .001), dependent functional status (P = .02), and the presence of disseminated cancer (P = .049) were predictive of undergoing HA compared to THA. CONCLUSION: As patients with metastatic cancer continue to live longer with their disease, the durability of surgical reconstruction to treat PPFFs is becoming increasingly important. This study demonstrated no significant differences in 30-day complications between PPFF patients treated with THA or HA after controlling for underlying confounders. These results suggest that THA can be utilized to treat certain patients with PPFFs, and future work is warranted to examine long-term functional outcomes.

Optimal Timing of Glucose Measurements After Total Joint Arthroplasty.

BACKGROUND: Postoperative glucose levels after total joint arthroplasty are important to monitor as hyperglycemia has been linked to complications such as periprosthetic joint infection. The purposes of this study were to identify how postoperative glucose values vary during the perioperative period and determine the optimal time to check glucose levels to best evaluate for hyperglycemia. METHODS: A retrospective study was conducted from September 2017 to September 2018 on 314 patients who underwent knee and hip arthroplasties. Blood glucose levels were collected immediately preoperatively, immediately postoperatively, at 5 PM on the day of surgery (DOS), at 9 PM on the DOS, and in the morning of postoperative day (POD) 1. The total number of hyperglycemic patients was assessed at 3 glucose thresholds: strict ≥ 126 mg/dL, intermediate ≥ 137 mg/dL, and lenient ≥ 180 mg/dL. Descriptive statistics were performed for each glucose time period, and adjusted comparisons were made between the mean glucose values and number of hyperglycemic patients at all time points. RESULTS: Mean (±95% confidence interval) glucose values were 105.7 ± 2.1 mg/dL preoperatively, 117.3 ± 2.5 mg/dL immediately postoperatively, 138.6 ± 4.3 mg/dL at 5 PM on the DOS, 142.9 ± 4.3 mg/dL at 9 PM on the DOS, and 116.7 ± 3.1 mg/dL in the morning of POD 1. Values measured at 5 PM and 9 PM were significantly higher than those measured at all other time points in both diabetics and nondiabetics (P < .001 for all). For all 3 hyperglycemia thresholds, the highest number of hyperglycemic patients was observed at 9 PM on the DOS: strict = 205 (65.3%) patients, intermediate = 177 (56.4%) patients; and lenient = 90 (28.7%) patients. CONCLUSION: Most patients who underwent total joint arthroplasty are hyperglycemic postoperatively, and 9 PM on the night of surgery may be the most sensitive time for detecting hyperglycemia in both diabetic and nondiabetic patients, in contrast to traditional POD 1 levels.

Efficacy of Patient-Specific Instruments in Total Knee Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: Patient-specific instrumentation (PSI) was introduced with the aim of making the procedure of total knee arthroplasty more accurate and efficient. The purpose of this study was to compare PSI and standard instrumentation in total knee arthroplasty with regard to radiographic and clinical outcomes as well as operative time and blood loss. METHODS: A meta-analysis was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. PubMed and Embase were searched from 2011 through 2015. We included randomized controlled trials and cohort studies that reported the effect of PSI on the aforementioned outcomes. The primary end point was deviation from the mechanical axis by >3°. Random and fixed-effect models were used for analysis. RESULTS: A total of 44 studies, which included 2,866 knees that underwent surgery with PSI and 2,956 knees that underwent surgery with standard instrumentation, were evaluated. The risk of mechanical axis malalignment was significantly lower for PSI, with a pooled relative risk of 0.79 (p = 0.013). The risk of tibial sagittal-plane malalignment was higher for PSI than for standard instrumentation (relative risk = 1.32, p = 0.001), whereas the risk of femoral coronal-plane malalignment was significantly lower (relative risk = 0.74, p = 0.043). The risk of tibial coronal-plane malalignment was significantly higher for PSI only when employing fixed-effect meta-analysis (relative risk = 1.33, p = 0.042). Minor reductions in total operative time (-4.4 minutes, p = 0.002) and blood loss (-37.9 mL, p = 0.015) were noted for PSI. CONCLUSIONS: PSI improves the accuracy of femoral component alignment and global mechanical alignment, but at the cost of an increased risk of outliers for the tibial component alignment. The impact of the increased probability of tibial component malalignment on implant longevity remains to be determined. Meta-analyses indicated significant differences with regard to operative time and blood loss in favor of PSI. However, these differences were minimal and, by themselves, not a substantial justification for routine use of the technology. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Aspirin mono-therapy continuation does not result in more bleeding after knee arthroplasty.

PURPOSE: Current clinical practice guidelines sometimes still recommend stopping aspirin five to seven days before knee arthroplasty surgery. Literature regarding multimodal blood management and continuation of anti-platelet therapy in this type of surgery is scant. The study hypothesis was that knee arthroplasty under low-dose aspirin mono-therapy continuation does not cause more total blood loss than knee arthroplasty performed without aspirin. Blood loss would be measured by haemoglobin (Hb) and haematocrit (HTC) levels drop at day 2 or day 4 for patients who benefit from multimodal bleeding control measures. METHODS: A database of all patients undergoing knee arthroplasty between 2006 and 2014 was analysed. Demographic, surgical and complete blood workup data were collected. A retrospective comparison study analysed both groups in terms of blood loss, by mean calculated blood loss as haemoglobin or haematocrit drop between the preoperative Nadir value and the postoperative day 2 and 4 value. A group of 198 (44 UKA and 154 TKA) patients underwent surgery without interrupting their aspirin therapy for cardiovascular prevention. Mean (SD) age was 71 (8) and the mean (SD) BMI was 29 (5.5) kg/m2. The control group consisted of 403 (102 UKA and 301 TKA) patients who were not under aspirin, or any other anti-platelet agent. Mean (SD) age was 65 (10) (p < 0.05) and the mean (SD) BMI was 29 (5.0) kg/m2 (n.s.). All patients in the control group were randomly selected. RESULTS: There were no differences in terms of visible (early) or hidden (late) blood loss as measured by Hb drop in between both groups. There is no difference in transfusion rates. CONCLUSIONS: Modern multimodal blood management provides sufficient blood loss prevention during and after knee arthroplasty to allow physicians to continue low-dose aspirin mono-therapy for cardiovascular prevention. LEVEL OF EVIDENCE: III.

Use of a haemostatic matrix (Floseal®) does not reduce blood loss in minimally invasive total knee arthroplasty performed under continued aspirin.

BACKGROUND: Aspirin is being used for primary and secondary cardiovascular prevention. It has been proposed that aspirin should be discontinued 5 to 7 days before surgery. However, discontinuation might increase the risk of cardiac and thrombo-embolic co-morbidity. Aspirin also increases the risk of bleeding during and after total knee arthroplasty. This study evaluated if the intra-articular use of a haemostatic matrix (Floseal®) might decrease blood loss in total knee arthroplasty performed under continued aspirin use. MATERIALS AND METHODS: We retrospectively compared matched pairs in two groups (80 patients in each group). Patients in both groups were taking aspirin: one group was managed with conventional haemostasis (with bovie electrocoagulation), while the other group was treated with an intra-articular haemostatic matrix as an adjunct to electrocoagulation. The outcomes compared were haemoglobin and haematocrit levels at days 2 and 4 after surgery as surrogates for blood loss, transfusion rate, surgical time, and length of stay in the hospital. RESULTS: No differences were observed between the two groups for haemoglobin and haematocrit levels on days 2 and 4. There were no differences in transfusion rate, surgical time or length of stay in hospital between the two groups. DISCUSSION: The present study shows that the use of Floseal® has no effect on reducing either visible or hidden blood loss after total knee arthroplasty with peri-operative continuation of aspirin use, as assessed by a drop in haemoglobin or haematocrit.

Use of a haemostatic matrix does not reduce blood loss in minimally invasive total knee arthroplasty.

BACKGROUND: Blood loss can increase morbidity and the risk of transfusion after total knee arthroplasty (TKA). This study evaluated the difference in blood loss between minimally invasive TKA performed with and without intra-articular use of a haemostatic matrix (Floseal®). MATERIALS AND METHODS: We retrospectively compared matched pairs in two groups (76 patients in each group): one group received conventional haemostasis (with bovie electrocoagulation), the other group was treated with an intra-articular haemostatic matrix (HM) as an adjunct to electrocoagulation. The outcomes compared were haemoglobin (Hb) and haematocrit levels at days 2 and 4 after surgery as a surrogate for blood loss, transfusion rate, surgical time, preoperative and postoperative range of motion (ROM) at days 21 and 42 and length of stay (LOS) in hospital. RESULTS: No differences were observed for Hb levels at day 2 or day 4 between men in the two groups. In women, however, the mean Hb at day 2 was 11.1 g/dL (SD 1.3) for TKA with HM and 12.0 g/dL (SD 0.9) for TKA without HM (p<0.001), while that at day 4 was 10.6 g/dL (SD 1.3) for TKA with HM and 11.4 g/dL (SD 1.2) for TKA without HM (p<0.001). The haematocrit was higher for TKA without HM at day 2 (p=0.001) and day 4 (p=0.008). The transfusion rate for TKA with HM was 2.6% and for TKA without HM 0% (p=0.497), while the mean surgical time was 93 minutes (SD 12) vs 87 minutes (SD 14), respectively (p=0.0055). There were no differences in preoperative or postoperative ROM at days 21 and 42 between the two groups. The LOS was longer for TKA with HM than for TKA without HM (4.5 days and 4 days, respectively, p=0.011) influenced by the longer stay for the transfused patients. DISCUSSION: The present study showed that the use of Floseal had no effect on reducing either visible or hidden blood loss after TKA, as assessed by a drop in Hb or haematocrit and that hidden blood loss was more important in women treated with the HM.

Lower blood loss after unicompartmental than total knee arthroplasty.

PURPOSE: It is intuitive that blood loss is lower after unicompartmental knee arthroplasty (UKA), but the difference in potential blood loss between UKA and total knee arthroplasty (TKA) has not yet been studied extensively. The hypothesis of this study was that blood loss is less important in UKA and that it can be performed without transfusion risk, even in preoperative anaemic patients. METHODS: A comparative matched retrospective study on 105 (57F/48M) UKA patients with a mean (SD) age of 64 (10) years, a mean (SD) BMI of 29.5 (5) kg/m(2) and a mean (SD) preoperative haemoglobin (Hb) level of 13.7 (1.5) g/dl was matched with 105 TKA patients for age, BMI, gender, ASA score and preoperative alignment. Blood loss was measured peroperatively and as a substitute for blood loss by mean Hb and haematocrit drop at day 2 and 4 postoperatively. RESULTS: Mean (SD) visible blood loss was lower for UKA [20 (10) cc vs. 110 (10) cc; P < 0.0001]. Mean (SD) Hb levels were higher for UKA compared to TKA at day 2 [12.9 (1.4) vs. 12.1 (1.4) g/dl; P < 0.0001], day 4 [12.7 (1.4) vs. 11.5 (1.6) g/dl; P < 0.0001] and day 21 [13.2 (1.4) vs. 12.7 (1.3) g/dl; P = 0.0185]. Hidden blood loss was more important for TKA (0.2 vs. 0.6 g/dl). Transfusion rates were 0 % for UKA and 2 % for TKA. Transfused patients were all female with moderate preoperative anaemia (Hb < 11 g/dl) undergoing TKA. CONCLUSIONS: Haemoglobin drop is higher with more hidden blood loss in TKA. Patients with preoperative anaemia can undergo UKA without a risk for transfusion; however, women with moderate anaemia planned for TKA are at risk. The transfusion rate for TKA is, however, very low, and so, expected survival of the implant versus risk of co-morbidity should be discussed with the patient. LEVEL OF EVIDENCE: Therapeutic study, Level III.

The use of patient-specific instruments does not reduce blood loss during minimally invasive total knee arthroplasty?

PURPOSE: Blood loss can be substantial and will influence morbidity and mortality after total knee arthroplasty. This study evaluated whether patient-specific instruments (PSI) can reduce blood loss because the intramedullary canal is not opened during the procedure and whether hidden blood loss can be reduced by its use. METHODS: Seventy-five patients operated with the Signature PSI technique were compared with a matched group operated with conventional instruments. Maximal drop in haemoglobin (Hb) and hematocrit (HTC) level were compared at day 2 and day 4. Transfusions were noted. Clinical outcomes like range of motion and knee society scores were studied as secondary outcomes. RESULTS: No statistically significant difference for calculated blood loss, maximal drop in Hb or HTC and transfusions were found. No clinical differences in range of motion or knee society scores were observed. CONCLUSIONS: The use of PSI-assisted total knee arthroplasty (TKA) did not result in less blood loss compared with conventional minimally invasive TKA with tourniquet. No reduction in hidden blood loss was observed either. According to this study, the argument of reduced transfusion cost should not be used in cost-effectiveness calculations of PSI-assisted TKA. LEVEL OF EVIDENCE: III.

Rotational alignment of the distal femur: anthropometric measurements with CT-based patient-specific instruments planning show high variability of the posterior condylar angle.

PURPOSE: Finding the anatomical landmarks used for correct femoral axial alignment can be difficult. The posterior condylar line (PCL) is probably the easiest to find during surgery. The aim of this study was to analyse whether a predetermined fixed angle referencing of the PCL could help find the surgical epicondylar axis (SEA) and this based on a large CT database with enough Caucasian diversity to be representable. METHODS: A total of 2,637 CT scans and 3D reconstructions from patients on four continents, executed for preoperative planning and creation of patient-specific instrumentation, were used to perform anthropometric measurements and to measure the posterior condylar angle (PCA) between the surgical epicondylar angle and the PCL. RESULTS: The mean (SD) PCA was 4° (1.4°) of external rotation. A significant correlation was found between more external rotation of the SEA and more proximal varus of the tibia or more distal valgus of the femur. For 59% of the study population, 4° external rotation from the PCL would be the right amount of axial rotation to align the femoral component in line with the SEA. Nine per cent needs less, and 32% needs more than 4° of axial rotation. On 105 (4%) CT-based 3D models, external rotation between 7° and 11° was measured and 77 (73%) of those cases were in varus or neutral alignment. In 132 patients, bilateral measurements were available and 94 (71%) had rotation within 1° of the opposite side. This last finding underlines that there is even an intra-individual difference in distal femoral anatomy that can range from 1° to 5°. CONCLUSIONS: This study was performed on a very large anthropometric CT and 3D models database and showed that there is a 41% risk of malalignment if a fixed PCA referenced of the PCL is used in total knee arthroplasty. The clinical importance of this study is the observation that femoral axial anatomy is individual and also that it is determined by the tibial anatomy. A group of patients needs more than the average external rotation because they have more distal femoral valgus with dysplastic condyles or more proximal tibial varus with a bigger medial condyle. LEVEL OF EVIDENCE: III.