Caliper-verified unrestricted kinematically aligned total knee arthroplasty in Asian patients showed efficacious mid- to long-term results regardless of postoperative alignment categories.

PURPOSE: There have been insufficient data regarding the long-term results of unrestricted kinematically aligned total knee arthroplasty (unKATKA) in Asian patients. We investigated mid- to long-term clinical and radiological follow-up data of Korean patients after caliper-verified unKATKA of minimum 7.4-10 years including categorised data of postoperative tibial component, limb and knee alignment. Additionally, we analysed the preoperative distribution and postoperative restoration of coronal plane alignment of knee (CPAK) phenotypes. METHODS: This study is a retrospective analysis of 63 patients: 96 osteoarthritic underwent consecutive caliper-verified unKATKA between October 2013 and May 2016 by a single surgeon. Implant survivorship was investigated for revision for any reason. Each knee was categorised into an in-range or outlier group by three postoperative alignment parameters: tibial component, knee and limb alignment. Statistical analyses were done for any significant differences in clinical scores and implant survival rates between groups. Finally, all knees were classified into CPAK classification postoperatively and postoperatively. The CPAK restoration rate was calculated. RESULTS: Among 85 knees in the clinically confirmed group, implant survival was 98.8%. There was one case of revision due to periprosthetic fracture. The percentage postoperatively aligned in the varus (valgus) outlier range was 100% (0%) for tibial component, 16.7% (24.8%) for the knee alignment and 51% (0%) for the limb alignment. All three categories did not affect implant survival or clinical scores. Eighty one out of 96 knees (84.4%) were restored to their CPAK phenotype postoperatively. CONCLUSION: With the limitation of a case series having a small number of patients and gender deviation, our study suggests that caliper-verified unKATKA could be a good option regardless of geographical variation of constitutional alignment in patients with osteoarthritis (OA). LEVEL OF EVIDENCE: Level IV, therapeutic study.

Current Incidence and Future Projection of Periprosthetic Fractures in South Korea: A Study Based on National Claim Database.

OBJECTIVE: To evaluate the current incidence and economic cost and to estimate the future burden of periprosthetic fracture (PF) after joint arthroplasties in South Korea. METHODS: This study was a retrospective registry-based study of patients who were diagnosed as periprosthetic fractures (PFs) in South Korea. Cases of PF from 2010 to 2017 in South Korea using Health Insurance and Review and Assessment (HIRA) database, which contains all medical claims for all South Korean patients, were identified. The operational definitions of PFs were identified from the Electronic Data Interchange (EDI) code of the Korean National Health Insurance Program (KHNIP). The annual incidence and medical costs during the period were calculated and the future increase of PF and its cost were projected through 2030 using generalized linear model with quasi-poisson link. RESULTS: During the 8-year period, 14,456 patients were treated due to PFs. The annual number of patients with PF remarkably increased from 1,322 in 2010 to 2,636 in 2017. The increment was prominent in age groups of 70-79 and ≧80. Total number of patients with PF were 9752 in women and 4704 in men during the study period. Mean personal costs were 1,155.4 USD in women and 1,185.5 USD in men. The total cost of PFs increased from 779,533 USD in 2010 to 3,888,402 USD in 2017. The personal cost of PFs also increased from 589.7 USD in 2010 to 1,475.1 USD in 2017. In 2017, the number of PF patients exponentially increased after 50 years of age especially in women. Estimated with our projection model, the number of PFs will increase by 2.5 times and the cost will increase by 10 times in the next 10 years. CONCLUSION: The incidence and cost of PFs are rising and will represent a serious socioeconomic burden in South Korea.

Cementless Hip Arthroplasty in Patients with Subchondral Insufficiency Fracture of the Femoral Head.

BACKGROUND: Subchondral insufficiency fracture of the femoral head (SIFFH) occurs in elderly patients and might be confused with osteonecrosis of the femoral head (ONFH). Subchondral insufficiency fracture of the femoral head is an insufficiency fracture at the dome of the femoral head and has been known to be associated with osteoporosis, hip dysplasia, and posterior pelvic tilt. This study's aims were to evaluate (1) surgical complications, (2) radiological changes, (3) clinical results, and (4) survivorship of THA in patients with SIFFH. METHODS: From November 2010 to June 2017, 21 patients (23 hips); 5 men (5 hips) and 16 women (18 hips) underwent cementless THA due to SIFFH at our institution. Their mean age was 71.9 years (range, 57 to 86) at the time of surgery, and mean T-score was -2.2 (range, -4.2 to 0.2). The mean lateral center-edge angle, abduction, and anteversion of the acetabulum were 29.9° (range, 14.8° to 47.5°), 38.5° (range, 31° to 45°), and 20.0° (range, 12° to 25°), respectively. The mean pelvic incidence, lumbar kyphotic angle and posterior pelvic tilt were 56.4° (range, 39° to 79°), 14.7° (range, -34° to 43°), and 13.0° (range, 3° to 34°), respectively. RESULTS: An intraoperative calcar crack occurred in 1 hip. The mean anteversion and abduction of cup were 29.0° (range, 17° to 43°) and 43.3° (range, 37° to 50°), respectively. One patient sustained a traumatic posterior hip dislocation 2 weeks after the procedure, and was treated with open reduction. At a mean follow-up of 35.4 months (range, 24 to 79 months), no hip had prosthetic loosening or focal osteolysis. At the latest follow-up, the mean modified Harris hip score was 79.1 (range, 60 to 100) points, and mean UCLA activity score was 4.2 (range, 2 to 7) points. The survivorship was 95.7% (95% CI, 94.9% to 100%) at 6 years. CONCLUSIONS: Cementless THA is a favorable treatment option for SIFFH in elderly patients. LEVEL OF EVIDENCE: 3.

Validation of an Operational Definition to Identify Distal Radius Fractures in a National Health Insurance Database.

PURPOSE: To develop and validate identification criteria for distal radius fractures (DRFs) and their treatment using a national health insurance database. METHODS: Patients who had at least 1 wrist radiograph taken in 2018 were recruited from a single academic referral hospital. After excluding patients who lacked immobilization code for wrist pathology, we collected data on the overall population. Because some patients might have undergone wrist radiography at another institution or had DRFs without an immobilization code, we additionally included patients who had a DRF diagnosis code at our institution. Reviews of medical records and wrist radiographs were considered for the diagnosis of DRF. We evaluated the sensitivity, specificity, and positive predictive value (PPV) of 3 operational definitions of fractures that were based on a single primary or secondary diagnosis code; all diagnosis codes, including primary and secondary codes; and all diagnosis and procedure codes. RESULTS: Among 768 patients included in the study, true DRFs were confirmed in 305. The sensitivity, specificity, and PPV for definition 1 were 91.5% (95% CI, 88.3%-94.6%), 97.5% (95% CI, 95.9%-99.1%), and 96.9% (95% CI, 94.9%-98.9%), respectively. Although the sensitivity of definition 2 was higher (92.1%; 95% CI, 89.1%-95.2%), its specificity and PPV were lower (96.4% [95% CI, 94.4%-98.3%] and 95.6% [95% CI, 93.2%-97.9%], respectively). The sensitivity of definition 3 was the lowest (88.2%; 95% CI, 84.6%-91.8%), but its specificity and PPV were the highest among the 3 definitions (98.6% [95% CI, 97.4%-98.8%] and 98.2% [95% CI, 96.6%-99.8%], respectively). CONCLUSIONS: Patients with DRFs can be identified from claims databases with high accuracy using an operational definition based on DRF diagnosis and procedure codes, including codes for surgical and nonoperative methods. CLINICAL RELEVANCE: Verified operational definitions will increase the consistency of results in future national health insurance database studies related to DRFs.

Burden and future projection of revision Total hip Arthroplasty in South Korea.

BACKGROUND: The annual number of hip arthroplasties is increasing combined with the aging population worldwide. In accordance with the increasing number of primary hip arthroplasties, the number of revision total hip arthroplasties (THAs) is expected to increase. The incidence and burden of revision THAs in the United States and have been reported by registry studies. To identify potential differences according to ethnics and regional practice, it is important to obtain data from East Asia. Nevertheless, there has been a lack of studies on the burden and future projection of revision THA based on a large-scale database in East Asia. The purpose of this study was to evaluate annual incidence and burden of revision THAs and to project the future burden in South Korea. METHODS: We identified primary THAs, primary hemiarthroplasties (HAs) and revision THAs, which were performed from 2010 to 2018, using database of Health Insurance and Review and Assessment (HIRA); nation-wide medical claim system of South Korea. The annual incidence rates (per 100,000) of primary THA, primary HA and revision THA, and the annual burden of revision THA; the number of revision THAs divided by the sum of primary hip arthroplasties and revision THAs, were calculated. The future burden of revision THAs were projected through 2030 using generalized linear model with Quasi-poisson regression. RESULTS: During the 9-year period, the annual incidences of primary THA, primary HA and revision THA increased by 47, 29 and 3%, respectively, while the revision burden decreased from 0.13 to 0.10. Compared to 2018, the annual incidences of primary THA, HA, and revision THA were projected to increase by 7.2, 2.3 and 1.1% per year, respectively, whereas the burden of revision THA was projected to decrease to 0.07 in 2030. CONCLUSION: Trends of revision THA in South Korea were similar with those of national registry studies from the United States. The annual incidence of revision THA has steadily increased, whereas its burden has decreased. Findings of our study could be used for epidemiological comparison between Western countries and East Asia as well as for the establishment of medical policies of revision THA in East Asian countries.

No Clinically Important Differences in Thigh Pain or Bone Loss Between Short Stems and Conventional-length Stems in THA: A Randomized Clinical Trial.

BACKGROUND: Short-length stems were developed to reduce bone loss of the proximal femur and potentially decrease the incidence of thigh pain after cementless THA. However, it remains unknown whether short stems indeed reduce bone loss or the frequency of thigh pain. QUESTIONS/PURPOSES: Is there a difference between short- and standard-length stems in terms of: (1) the frequency or severity of thigh pain, (2) modified Harris hip scores, (3) implant loosening, or (4) bone mineral density as measured by dual-energy x-ray absorptiometry? METHODS: Between March 2013 and January 2014, three surgeons performed 205 primary THAs. To be eligible, patients needed to be at least 20 years of age, have not undergone previous history of hip surgery, and have no metabolic bone disease. A total of 100 patients were randomized to receive THA either with a short stem (n = 56) or with a standard-length stem (n = 44). Both stems were proximally coated, tapered, cementless stems. Compared with standard stems, short stems typically were 30- to 35-mm shorter. A total of 73% (41 of 56) and 77% (34 of 44) of those groups, respectively, were accounted for at a minimum of 5 years and were analyzed. The presence of thigh pain during activity was evaluated using a 10-point VAS, and the modified Harris hip score was calculated by research assistants who were blinded to the treatment groups. Plain radiographs were taken at 6 weeks, 6 months, and 12 months postoperatively, and every 1 year thereafter; loosening was defined as subsidence > 3 mm or a position change > 3° on serial radiographs. Radiological assessment was performed by two researchers who did not participate in the surgery and follow-up evaluations. Bone mineral density of the proximal femur was measured using dual-energy x-ray absorptiometry at 4 days, 1 year, 2 years, and 5 years postoperatively. The primary endpoint of our study was the incidence of thigh pain during 5-year follow-up. Our study was powered at 80% to detect a 10% difference in the proportion of patients reporting thigh pain at the level of 0.05. RESULTS: With the numbers available, we found no difference between the groups in the proportion of patients with thigh pain; 16% (9 of 56) of patients in the short-stem group and 14% (6 of 44) of patients in the standard-stem group experienced thigh pain during the follow-up period (p = 0.79). In all patients, the pain was mild or moderate (VAS score of 4 or 6 points). Among the 15 available patients who reported thigh pain, there was no difference between the implant groups in mean severity of thigh pain (4.3 ± 0.8 versus 4.2 ± 0.7; p = 0.78). There were no between-group differences in the short versus standard-length stem groups in terms of mean modified Harris hip score by 5 years after surgery (89 ± 13 versus 95 ± 7 points; p = 0.06). No implant was loose and no hip underwent revision in either group. Patients in the short-stem group showed a slightly smaller decrease in bone mineral density in Gruen Zones 2, 3, and 5 than those in the standard-stem group did; the magnitude of the difference seems unlikely to be clinically important. CONCLUSION: We found no clinically important differences (and few differences overall) between short and standard-length THA stems 5 years after surgery in a randomized trial. Consequently, we recommend that clinicians use standard-length stems in general practice because standard-length stems have a much longer published track record in other studies, and short stems can expose patients to the uncertainty associated with novelty, without any apparent offsetting benefit. LEVEL OF EVIDENCE: Level I, therapeutic study.

Risk of Osteoporotic Fracture in Patients with Breast Cancer: Meta-Analysis.

BACKGROUND: The fracture risk induced by anti-estrogen therapy in patients with breast cancer remains controversial. The aim of this study was to perform a meta-analysis and systematic review to evaluate the risk of osteoporotic fracture in patients with breast cancer. METHODS: A systematic search was performed to identify studies that included any osteoporotic fracture (hip fracture and vertebral fracture) in patients breast cancer. Main outcome measures were occurrence and risk of osteoporotic fractures including hip and vertebral fractures in patients and controls. RESULTS: A systematic search yielded a total of 4 studies that included osteoporotic fracture outcomes in patients with breast cancer. Meta-analysis showed a higher risk of osteoporotic fracture in patients with breast cancer. Analysis of these 4 studies involving a total of 127,722 (23,821 cases and 103,901 controls) patients showed that the incidence of osteoporotic fractures was higher in the breast cancer group than in the control group. The pooled estimate of crude relative risk for osteoporotic fracture was 1.35 (95% confidence interval, 1.29-1.42; P<0.001). CONCLUSIONS: Although studies were limited by a small number, results suggested a possible association between anti-estrogen therapy and increased risk of osteoporotic fractures in patients with breast cancer.

Urinary retention after total joint arthroplasty of hip and knee: Systematic review.

PURPOSE: Postoperative urinary retention (POUR) is a common complication after total joint arthroplasties (TJAs). The POUR is managed with urinary catheterization, which is associated with a risk of urinary tract infection and subsequent periprosthetic joint infection. The purpose of this review was to afford a comprehensive understanding of POUR and its management. METHODS: We identified 15 original articles concerning POUR after TJA, which were published from January 2010 to February 2019. The diagnostic method, incidence, risk factors, and management of POUR of the 15 studies were reviewed. RESULTS: The incidence of POUR was ranged from 4.1% to 46.3%. Ultrasound was used for the detection of POUR among the total of the 15 studies. The following factors of old age, male gender, benign prostatic hypertrophy, history of urinary retention, spinal/epidural anesthesia, excessive fluid administration, patient-controlled analgesia, the use of opiates, underlying comorbidities, and poor American Society of Anesthesiologists (ASA) grade were risk factors for POUR. Most of the studies did not use indwelling catheterization during surgery. The POUR patients were managed with intermittent catheterization. The most common volume criterion for bladder catheterization was 400 mL. In inevitable use of an indwelling catheter, it should be removed within 48 h. CONCLUSIONS: This review provided an up-to-date guide for the detection and management of POUR. LEVEL OF EVIDENCE: Level III.

Normal Ischiofemoral Distance and Its Associated Factors: Computed Tomography-Based Study.

PURPOSE: The purposes of this study are (1) to measure the ischiofemoral distance (IFD) in nondiseased hips and (2) to reveal patient demographic and anatomical factors associated with IFD. METHODS: In this retrospective study, we identified patients who had unilateral osteonecrosis of the femoral head on computed tomography (CT) scan from November 2005 to July 2018 and assessed the unaffected contralateral hips of the patients. Among the contralateral hips, we excluded hips with hip pain, incomplete or poor-quality CT image, incomplete medical record, degenerative arthritis of the hip, or previous hip surgery. IFD was measured on the axial CT image, and correlated demographic factors (age, sex, height, weight, and body mass index) and anatomical parameters (neck-shaft angle of the femur and femoral anteversion) with IFD were evaluated. RESULTS: Five hundred seventeen patients (517 hips) were evaluated. There were 302 men and 215 women, and their mean age was 51.7 years (range 15-83 years). The mean IFD was 33.2 (±9.2) mm in men and 24.3 (±8.9) mm in women (P < .001). Interobserver and intraobserver reliability (intraclass correlation coefficients) were 0.99 (95% confidence interval 0.98-1.0) and 0.98 (95% confidence interval 0.97-0.99), respectively. The mean neck-shaft angle was 129.31° ± 5.04° in males and 129.93° ± 6.29° in females. The mean femoral anteversion was 9.72° ± 7.95° in males and 12.61° ± 8.91° in females. IFD was positively correlated with height (correlation coefficient [r] = 0.464, P < .001) and weight (0.286, P < .001), whereas it was negatively correlated with age (-0.198, P < .001), neck-shaft angle (-0.123, P = .005), and femoral anteversion (-0.346, P < .001). There was no correlation between body mass index and IFD (P = .522). In multivariate regression analysis, IFD was positively associated with height (ß = .632), and negatively associated with neck-shaft angle of the femur and femoral anteversion (ß = -0.155 and -0.328. respectively). CONCLUSIONS: In asymptomatic hips, the mean IFD was 33.2 ± 9.2 mm in males and 24.3 ± 8.9 mm in females. The IFD was positively correlated with height and negatively with neck-shaft angle of the femur and femoral anteversion. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Concomitant Septic Arthritis of the Hip in Patients with Osteonecrosis of the Femoral Head.

INTRODUCTION: Septic hip is a rare condition and is known to occur in immune-compromised patients. In general, surgeons are not concerned about the superimposed septic hip when they operate on patients with osteonecrosis of the femoral head (ONFH) if the patient is not immune compromised. We evaluated 1) the proportion of septic arthritis among patients with ONFH, 2) the clinical and laboratory features, and 3) the outcomes of two-stage THA in those patients. MATERIALS AND METHODS: We identified patients who were diagnosed as having concomitant septic arthritis of the hip among 1,226 patients who underwent THA due to ONFH from 2011 to 2018 at our institution. A diagnosis of septic arthritis was made by aspirated joint fluid; white blood cell (WBC) count >15,000/ml and neutrophils >75%, microbiological culture, and/or the findings of septic arthritis on magnetic resonance imaging (MRI) scan. Osteonecrotic patients with infection were treated with two-stage THA. RESULTS: Among the 1,226 osteonecrotic patients, 14 (1.1%) had concomitant septic arthritis of the hip. There were nine men and five women. None of them were immune compromised or had a remote septic focus. In the preoperative evaluation, all 14 patients had elevated serum erythrocyte sedimentation rate (ESR) (>20mm/hr) and/or C-reactive protein (CRP) (>0.5mg/dL), and three patients had a fever (>37.5°C). Findings of septic hip were seen in all 12 patients who had preoperative MRI. The neutrophil count in the high-power field was >5 in all 12 patients who had intraoperative frozen section histology. The 14 patients were followed for one to seven years after the arthroplasty, and no patient had evidence of infection at the final follow up. CONCLUSION: When a patient with ONFH has an unexplained elevation of ESR and/or CRP, concomitant septic arthritis of the hip should be suspected.

Transcultural adaptation and psychometric properties of the Korean version of the Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO-41).

We translated and adapted transculturally the Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO-41) for Korean patients. The translated Korean version of QUALEFFO-41 showed satisfactory reliability and validity. PURPOSE: The aim of this study was to translate the QUALEFFO-41 for Korean patients and then validate the Korean version of QUALEFFO-41. METHODS: Translation and transcultural adaptation of the QUALEFFO-41 was conducted according to the international recommendations. Ninety-seven patients (mean age, 73.6 years) with osteoporosis were participated in validating the Korean version of QUALEFFO-41. To test reliability, internal consistency was evaluated using Cronbach's alpha coefficient. To test validity, convergent validity was assessed using correlation with the SF-12 and EQ-5D and discriminant validity was assessed using ROC curve analysis. RESULTS: The English version of QUALEFFO-41 was translated and adapted to Korean without notable discrepancies. The Korean QUALEFFO-41 had good reliability with Cronbach's alpha ranging from 0.733 to 0.942. QUALEFFO-41 had good correlations to SF-12 and EQ-5D. Compared with subjects without history of vertebral fracture (VF), those with history of VF showed significantly worse scores according to QUALEFFO-41, but not according to SF-12 or EQ-5D. ROC curve analysis revealed that the physical function domain of QUALEFFO-41 had significant ability to discriminate between subjects with and without history of VF, while SF-12 or EQ-5D did not. CONCLUSIONS: The Korean version of QUALEFFO-41 demonstrated relevant internal consistency, convergent validity, and discriminant validity, which can be recommended to evaluate quality of life in Koreans.

Prevalence of Cam Deformity with Associated Femoroacetabular Impingement Syndrome in Hip Joint Computed Tomography of Asymptomatic Adults.

PURPOSE: Femoroacetabular impingement (FAI) is considered an important cause of early degenerative arthritis development. Although three-dimensional (3D) imaging such as computed tomography (CT) and magnetic resonance imaging are considered precise imaging modalities for 3D morphology of FAI, they are associated with several limitations when used in out-patient clinics. The paucity of FAI morphologic data in Koreans makes it difficult to select the most effective radiographical method when screening for general orthopedic problems. We postulate that there might be an individual variation in the distribution of cam deformity in the asymptomatic Korean population. MATERIALS AND METHODS: From January 2011 to December 2015, CT images of the hips of 100 subjects without any history of hip joint ailments were evaluated. A computer program which generates 3D models from CT scans was used to provide sectional images which cross the central axis of the femoral head and neck. Alpha angles were measured in each sectional images. Alpha angles above 55° were regarded as cam deformity. RESULTS: The mean alpha angle was 43.5°, range 34.7-56.1°(3 o'clock); 51.24°, range 39.5-58.8°(2 o'clock); 52.45°, range 43.3-65.5°(1 o'clock); 44.09°, range 36.8-49.8°(12 o'clock); 40.71, range 33.5-45.8°(11 o'clock); and 39.21°, range 34.1-44.6°(10 o'clock). Alpha angle in 1 and 2 o'clock was significantly larger than other locations (P<0.01). The prevalence of cam deformity was 18.0% and 19.0% in 1 and 2 o'clock, respectively. CONCLUSION: Cam deformity of FAI was observed in 31% of asymptomatic hips. The most common region of cam deformity was antero-superior area of femoral head-neck junction (1 and 2 o'clock).

Does femoral offset recover and affect the functional outcome of patients with displaced femoral neck fracture following hemiarthroplasty?

BACKGROUND: Restoring preoperative horizontal femoral offset (FO) promised good functional outcome in patients receiving total hip arthroplasty. However, relatively little was known regarding the clinical relevance of restoring the offset in patients with bipolar hemiarthroplasty to treat displaced femoral neck fracture. Therefore, the objective of this study was to evaluate postoperative FO accurately and verify its relation with functional outcome. METHODS: One hundred elderly patients who received bipolar hemiarthroplasty to treat displaced femoral neck fracture were identified. Preoperative CT scanning of contralateral hip joint and reconstruction of images led to rotation-free FO. By referencing postoperative implant specification and comparing to measured values in Picture Archive and Communication System, rotation-free postoperative FO and the amount of change were acquired. Postoperative Harris Hip Score (HHS) and Modified Barthel Index (MBI) were evaluated to measure functional outcome at 12-month after the surgery. Patients with significant FO change were identified. Multiple regression analysis was conducted to determine if the FO change might independently affect the outcome regardless of confounding factors. RESULTS: The mean preoperative offset was 37.4±2.5 increased by 12.7±9.6% after the surgery. Only 25.0% of postoperative offset after hemiarthroplasty was changed within ±5% of preoperative offset. A total of 45.0% of postoperative offset changed within ±10% while 77.0% of postoperative offset changed within ±20%. 23% of patients whose FO changed more than 20% showed significantly worse outcome score than the patients whose FO change remained within ±20% of initial value. Mean MBI and HHS were negatively correlated with FO change. After adjusting for confounding factors, significant correlation remained between modification of FO and MBI, but not between FO change and HHS (B=4.576; ß=0.235; 95% confidence interval of B: 0.534 to 8.135). CONCLUSIONS: FO was not properly restored in 23% of subjects receiving bipolar hemiarthroplasty due to femoral neck fracture. FO restoration independently predicted fair MBI after the surgery. Therefore, surgeons should pay attention to restoring FO with meticulous templating.