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.

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.

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.

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.

Comparison of local infiltration analgesia with single injection femoral nerve block in total knee arthroplasty.

The purpose of this study was to compare the analgesic and hemostatic effects of Local Infiltration Analgesia (LIA) with single injection femoral nerve block (SFNB). A database of patients undergoing knee arthroplasty between 2008 and 2013 was analyzed. A group of patients who underwent minimally invasive TKA either with SFNB (n = 112) or with LIA (n = 112) were matched. In the early postoperative period, the LIA group had a significantly lower VAS score, a lower drop in Hb and a lower length of hospital stay. Both the SFNB and LIA techniques provide excellent pain relief following TKA. Nevertheless, LIA reduces pain better in the very early postoperative period by a more complete nerve blockade allowing immediate postoperative mobilization and ambulation leading to a shorter hospital stay. Furthermore, LIA decreases perioperative blood loss by its local hemostatic effect.

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.

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.

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.

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.

The difference between weight-bearing and non-weight-bearing alignment in patient-specific instrumentation planning.

PURPOSE: Retrospective study to analyse the difference between weight-bearing and non-weight-bearing alignment in osteoarthritic knees planned for patient-specific instrumented (PSI) total knee arthroplasty (TKA). The aim of the study is to observe whether a difference in alignment can be linked to arthritis staging or zone mechanical axis. METHODS: Full-leg standing radiographs and non-weight-bearing MRI of the whole leg were compared for hip-knee-ankle (HKA) angle, measured according to Moreland criteria, in seventy osteoarthritic patients. Kellgren-Lawrence (KL) staging and classification according to zone mechanical axis with Kennedy zones was done. RESULTS: A mean preoperative HKA angle on standing radiographs of 176.4° ± 7.2° was measured compared to 176.4° ± 6.9° for the MRI whole-leg HKA angle. A difference of 0°-1° was observed in 54% of patients when comparing the weight-bearing with the non-weight-bearing HKA angle. Twenty-three per cent had a difference of 2° and another 23 % a difference of 3° or more. In female patients, the dynamic load pattern of weight-bearing increases the HKA angle due to convex side soft tissue laxity both in varus and valgus knees. More important differences were observed in the KL stage 3 and 4 patients (P < 0.05) and with a load-bearing axis outside of the articular surface (P < 0.05). CONCLUSION: Surgeons should be aware that there is a difference between weight-bearing and non-weight-bearing alignment in patients with Kellgren-Lawrence 3 and 4 with a load-bearing axis outside of the articular surface (Kennedy 0 or 1 or 5). According to this study, these changes seem related to the amount of articular wear and the load-bearing axis. This is important for the preoperative planning process in PSI-assisted TKA. More concave side ligamentous release or more constraint can be necessary than imagined based on the PSI alignment result. Full-leg standing radiographs should be performed for PSI-assisted TKAs to analyse the position of the load-bearing axis. LEVEL OF EVIDENCE: IV.

The combined Whiteside's and posterior condylar line as a reliable reference to describe axial distal femoral anatomy in patient-specific instrument planning.

PURPOSE: Aligning the femoral component in the axial plane parallel to the surgical epicondylar axis (SEA) has been generally recommended. In this retrospective study on the axial anatomy of the distal femur, as determined by the patient-specific instruments (PSI) planning tool based on MRI and 3D reconstructions, the different rotational axes were compared. The purpose of this study was to compare the impact of posterior axial anatomy on anterior anatomy and to compare the different angles of rotation obtained by a PSI-planning engineer. METHODS: The preoperative planning of 77 PSI patients with a mean (SD) age of 65.6 (9.6) years undergoing primary total knee replacement for osteoarthritis was analysed for rotational anatomy of the distal femur. The angles between the posterior condylar line (PCL) and the SEA called posterior condylar angle (PCA), between Whiteside's line and the SEA and finally between Whiteside's line and the PCL, were retrieved from the PSI axial rotation planning screen. RESULTS: The mean (SD) PCA was 3.2° (1.4°). The mean (SD) angle between Whiteside's line and the SEA was 91.4° (2.2°), and the mean (SD) angle between Whiteside's line and the PCL was 94.5° (2.3°). No significant difference for this last rotational parameter was found in between varus and valgus knees. CONCLUSION: Patient-specific instrument's preoperative planning found consistent angles to describe the distal femoral anatomy as previously published in the literature. The angle between Whiteside's line and the PCL as measured on PSI planning is a mean angle of 94.5° (2.3°) for both varus and valgus knees. Setting a fixed PCA of 5° of external rotation referenced of the PCL makes this planning repeatable during conventional surgery. LEVEL OF EVIDENCE: Therapeutic study, Level III.

The minimally invasive far medial subvastus approach for total knee arthroplasty in valgus knees.

PURPOSE: The lateral approach in the valgus knee asks for a lot of soft tissue releases during the arthrotomy. The hypothesis of this study was that the far medial subvastus approach could be used in valgus knees and would guarantee both functional and radiological good to excellent results. METHODS: This is a retrospective study on 78 patients (84 knees) undergoing primary total knee arthroplasty (TKA) for type I or II fixed valgus knees. The mean (SD) preoperative mechanical alignment was 187° (4°) HKA angle. Functional recovery, pain, tourniquet times, necessary soft tissue releases as well as radiological alignment were measured. RESULTS: The Knee Score improved significantly from 45 (10) to 90 (10) (P < 0.05) and the function score improved as well from 35 (20) to 85 (10) (P < 0.05). Flexion improved from 110° (10°) to 137° (8°). Hospital stay was 4 (1.2) days. Alignment was corrected to 181° (1.5°) HKA angle with a postoperative joint line shift of +2.8 (3.2) mm. No clinical instability, as evaluated by the senior author, or osteolytic lines was observed at minimal one-year radiological follow-up. CONCLUSION: The far medial subvastus approach is an excellent approach to perform Krackow type I and II TKA with primary PS implants.

Monoclonal antibody anti-sclerostin for treatment of pelvic insufficiency fractures in adult hypophosphatasia: A case report.

Hypophosphatasia is a rare inherited metabolic disease leading to inhibition of bone and teeth mineralization that can be complicated by multiple insufficiency fractures. Treatment is currently limited to enzyme replacement therapy using bone-targeting recombinant human alkaline phosphatase, or asfotase alfa. Romosozumab is a monoclonal anti-sclerostin antibody originally indicated for the treatment of osteoporosis in postmenopausal women with high-risk of fracture. Recently its indication had been expanded to other metabolic bone disorders such as osteogenesis imperfecta. We report a unique case of a 67-yer-old female with hypophosphatasia complicated by multiple delayed-union and nonunion insufficiency fractures of the pelvis. After 12-month therapy with Romosozumab to address her osteoporosis, the patient healed her fractures and increased her bone mass density. Our case report shows interesting effects of Romozumab in an adult patient with hypophosphatasia. It not only helped increase bone density, but also help in the healing process of delayed-union and nonunion insufficiency fractures of the pelvis and prevented the occurrence of new fractures during the treatment period. To our knowledge, this is the first report describing the potential effect of Romosozumab on insufficiency fractures in patients with hypophosphatasia.

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.

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.

Elbow Arthroscopy for Posteromedial Impingement and Fixation of Olecranon Stress Fracture.

Posteromedial elbow impingement due to valgus extension overload often develops as a result of excessive valgus and extension force during repetitive overhead throwing activities. Impingement classically occurs in throwing athletes such as baseball, tennis, softball, or lacrosse players. If isolated, arthroscopic removal of the posteromedial olecranon osteophytes shows excellent postoperative satisfaction, return to sport rates, and return to previous level of activity. This Technical Note describes treatment of posteromedial elbow impingement syndrome and associated olecranon stress fracture treated with arthroscopic removal of posteromedial osteophytes and arthroscopic-assisted screw fixation.

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.

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.

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.