Kocher Criteria Research Articles

Impact of delayed presentation and surgical management on radiologic and clinical outcomes of pediatric septic hip

BackgroundSeptic arthritis of the hip joint (septic hip) is the bacterial infection of the hip. Delayed treatment increases the risk of extensive joint damage, systemic infection, prolonged recovery, higher healthcare costs, and long-term disability. This study explores the repercussions of delayed surgical treatment in pediatric septic hip. MethodsIn this observational study, pediatric patients diagnosed with septic hip between 2012 and 2021 were retrospectively selected from a major referral center in Shiraz, Iran. We collected clinical and radiological data, including Kocher score and determined Choi classification in follow-up radiographs. Multivariate logistic regression analysis was used to assess the impact of delay to surgery on the development of clinical sequelae and radiological deformities in the presence of potential confounders of age and Kocher criteria. ResultsOut of 49 children with delayed presentation, 46 survived and entered the study. Mean delay from symptom presentation to admission was 12.67 ± 10.51 days, and mean delay from admission to surgery was 5.33 ± 6.47 days. Of the 46 patients, 28.26% developed clinical sequelae. The Choi classification revealed that 54.35% of patients developed no residual deformity. A multivariate logistic regression analysis indicated a statistically significant association between delay to surgery and the development of radiological deformities (adjusted odds ratio: 1.36, 95% CI: 1.14–1.64, p = 0.001). Additionally, a separate analysis revealed that each additional day of delay was associated with a 12% increase in the odds of clinical sequelae (adjusted odds ratio: 1.12, 95% CI: 1.03–1.22, p = 0.006). Sensitivity analyses confirmed the relationship of delay from admission to surgery in developing both outcomes. ConclusionDelay in medical care and surgical management remains the most important factor affecting the outcomes of septic hip. The study underscores the critical role of timely surgical intervention in reducing complications in pediatric septic hip patients.

C-reactive protein of ≥ 20mg/L and ultrasound finding of an effusion ≥ 7mm has a high specificity and sensitivity in diagnosing paediatric hip septic arthritis.

Differentiating septic arthritis (SA) from transient synovitis (TS) in children remains a diagnostic challenge. Several algorithms have been developed to diagnose SA including Kocher's criteria and its subsequent modifications, but reports show variable efficacy. This study aims to examine the diagnostic utility of a novel method only using C-reactive protein (CRP) and ultrasound (US) findings of effusion in differentiating SA from TS, determine the optimal values for these predictors and validate this method against existing clinical predictors. A 5-year retrospective study was performed including all paediatric patients with acute, non-traumatic hip pain with a suspicion of SA. All patients were evaluated using Kocher's criteria, Caird's criteria, and the novel method. Multivariate logistic regression was performed to identify independent clinical predictors of SA. The degree of agreement between the various methods were assessed using Cohen's kappa (k). Receiver operating characteristics (ROC) curves were used to examine the diagnostic accuracy of this novel method as well as to determine optimal cut-offs for US effusion and CRP in diagnosing SA. Hundred and one patients were recruited. CRP and effusion on US were found to be independent predictors of SA. Both Kocher's and Caird's method showed good specificity (98.9%) but extremely poor sensitivity for SA (0%). When Kocher's four clinical predictors were present, probability of SA was only 59.16%. The k for both Kocher's and Caird's methods, was -0.017 indicating poor agreement. However the k in the novel method was 0.641, indicating good agreement. Our study showed that the novel method using CRP (≥ 20mg/L) and US finding of effusion (≥ 7mm) has a high specificity (97%) and sensitivity (71%) in diagnosing SA.

Age and C-reactive protein as modifiers of Kocher criteria in pediatric septic knee monoarthritis

IntroductionAlthough Kocher criteria can distinguish a septic hip from an aseptic cause, they may not apply to a septic knee. We aimed to identify predictors to discriminate septic and aseptic causes of acute knee monoarthritis in children who underwent arthrocentesis. MethodsWe conducted a retrospective cohort study among children who underwent arthrocentesis for suspected septic arthritis of the knee. Collected data included demographic, clinical and laboratory characteristics. We performed univariate and multivariable analyses to identify predictors of the septic knee. We further investigated accuracy of different predictive models. ResultsA total of 60 patients who underwent arthrocentesis for suspected knee septic arthritis were included in this study. Septic arthritis of the knee was confirmed in 32 (53%) patients. Age ≤ 5 years (OR 4.237, [95% CI 1.270–14.127], p = 0.019), WBC > 12,000 cells/mm3 (OR 5.059, [95% CI 1.424–17.970], p = 0.012), and CRP > 2 mg/dL (OR 3.180, [0.895–11.298], p = 0.074) were the most important predictors of a septic knee. Three-tier model comprising these three factors (AUC 0.766) and 4-tier model with addition of fever >38.5°C (AUC 0.776) performed better than Kocher criteria (AUC 0.677), modified Kocher criteria (AUC 0.699) and Full Model (adding age ≤ 5 years and CRP >2 mg/dL to Kocher criteria) (AUC 0.746). Full Model successfully ruled out septic arthritis if all 6 criteria were negative. ConclusionBased on these findings, we propose an algorithm to identify low, intermediate and high-risk patients for knee septic arthritis. Our proposed two-step algorithm incorporating major (age, WBC, CRP) and minor (fever, ESR, non-weight bearing) criteria can serve as a simple decision-support tool to justify arthrocentesis in children with suspected knee septic arthritis.

The modified Kocher criteria for septic hip: Does it apply to the knee?

Background:Pediatric septic arthritis is a surgical emergency and timely diagnosis prevents serious complications. To differentiate between septic hip and transient synovitis, the predictive value of four original Kocher criteria (fever, inability to bear weight, elevated serum white blood cell count, and elevated erythrocyte sedimentation rate) plus Caird’s addition of elevated C-reactive protein have been studied, termed the modified Kocher criteria. These criteria have not been tested extensively on septic knee. This study tested the utility of the modified Kocher criteria in predicting septic knee while validating it for septic hip.Methods:A retrospective chart review was conducted of pediatric patients evaluated at a single institution for irritable hip or knee between 2009 and 2018. Patients who underwent arthrocentesis were included and the modified Kocher criteria were applied to all.Results:One hundred fifty-five patients (96 hips and 59 knees) were identified. One hundred four (67.1%) patients had septic arthritis with 44/59 (74.6%) of knees and 60/96 (62.5%) of hips. The strongest predictors for septic hip and knee were elevated C-reactive protein (odds ratio = 26.9, p < 0.0001) and refusal to bear weight (odds ratio = 14.5, p < 0.0001), respectively. For hips, 5/5 criteria produced a 100% positive predictive value for septic arthritis. For knees, the combination of inability to bear weight and elevated C-reactive protein had a positive predictive value of 89.7%.Conclusion:While all five of the modified Kocher criteria are not predictive of pediatric septic knee, the combination of two specific factors (inability to bear weight and elevated C-reactive protein) is strongly predictive. This study validates previous work that the modified Kocher criteria are predictive of septic hip.Level of evidence:level III

The Use of Biomarkers in the Early Diagnosis of Septic Arthritis and Osteomyelitis-A Pilot Study.

The diagnosis of septic arthritis (SA) and osteomyelitis (OM) has remained challenging in the pediatric population, often accompanied by delays and requiring invasive interventions. The purpose of this pilot study is to identify a novel panel of biomarkers and cytokines that can accurately differentiate SA and OM at initial presentation using serum alone. Twenty patients below 18 years old whose working diagnosis included SA (n=10) and OM (n=10) were identified. Serum was collected at initial evaluation. Each sample underwent seven ELISA [C1-C2, COMP, CS-846, hyaluronan, procalcitonin, PIIANP, C-terminal telopeptide of type II collagen (CTX-II)] and 65-plex cytokine panels. Principal component and Lasso regression analysis were performed to identify a limited set of predictive biomarkers. Mean age was 4.7 and 9.5 years in SA and OM patients, respectively (P=0.029). 50% of SA patients presented within 24 hours of symptom onset, compared with 0% of OM patients (P=0.033). 30% of SA patients were discharged home with an incorrect diagnosis and re-presented to the emergency department days later. At time of presentation: temperature ≥38.5°C was present in 10% of SA and 40% of OM patients (P=0.12), mean erythrocyte sedimentation rate (mm/h) was 51.6 in SA and 44.9 in OM patients (P=0.63), mean C-reactive protein (mg/dL) was 55.8 in SA and 71.8 in OM patients (P=0.53), and mean white blood cells (K/mm3) was 12.5 in SA and 10.4 in OM patients (P=0.34). 90% of SA patients presented with ≤2 of the Kocher criteria. 100% of SA and 40% of OM patients underwent surgery. 70% of SA cultures were culture negative, 10% MSSA, 10% Kingella, and 10% Strep pyogenes. 40% of OM cultures were culture negative, 50% MSSA, and 10% MRSA. Four biomarkers [CTx-II, transforming growth factor alpha (TGF-α), monocyte chemoattractant protein 1 (MCP-1), B cell-attracting chemokine 1] were identified that were able to classify and differentiate 18 of the 20 SA and OM cases correctly, with 90% sensitivity and 80% specificity. This pilot study identifies a panel of biomarkers that can differentiate between SA and OM at initial presentation using serum alone. Level II-diagnostic study.

Urine Dipstick Leukocyte Esterase in the Rapid Diagnosis of Septic Arthritis.

This study aimed to evaluate the sensitivity and specificity of the leukocyte esterase (LE) band in two groups of patients receiving and not receiving antibiotics and compare the results. This prospective cross-sectional study was conducted on 105 joints with clinical suspicion of infectious arthritis (based on Kocher criteria) admitted in Shohada Hospital, Tabriz, Iran, within 2017-2018. Patients were divided into two groups, including receiving antibiotics (n=29; group 1) and not receiving antibiotics (n=76; group 2). Articular fluid aspiration was performed under sterile conditions with an 18-gauge angiocath with at least 1 ml volume of the hip, knee, ankle, elbow, and shoulder joints. Polymorphonuclear cell percentage count, cell count, Gram staining (GS), culture, and leukocyte esterase test were performed immediately after the aspiration of the specimens. Levels of synovial fluid white blood cell count, serum white blood cell count, PMN, serum glucose, erythrocyte sedimentation rate, C-reactive protein, and time of aspiration (TOA) were significantly higher in the group receiving antibiotics (P<0.05). Synovial glucose levels were significantly lower in the group receiving antibiotics. Furthermore, the positive frequency of glucose esterase, blood culture, GS, serum culture, and ultimate diagnosis of septic arthritis tests were significantly lower in the antibiotic receiving group (P<0.05). The sensitivity, and positive predictive value of the leukocyte esterase test were obtained at 100%, and 96.55% in the antibiotic receiving group, respectively. Moreover, in the group not receiving antibiotics, the sensitivity, specificity, positive predictive value, and negative predictive value of the leukocyte esterase test were estimated at 72.22%, 92.50%, 89.66%, 78.72%, respectively. Antibiotic use and the prolongation of TOA lead to increased inflammatory products, which is interfering with lab variables. As a result, they increase the sensitivity of the test. The sensitivity and specificity of the leukocyte esterase test in patients who did not receive antibiotics showed that this was a suitable and reliable laboratory method for the rapid detection of infectious arthritis that required an emergency rescue procedure.

Lyme Arthritis in the Pediatric Knee: Clinical and Magnetic Resonance Imaging Differentiators.

The medical records and MRI scans of children who presented between 2009 and 2019 with an acute knee effusion ultimately diagnosed as LA or SA were retrospectively reviewed. Data collection included clinical information on the modified Kocher criteria (weight-bearing, fever, blood serology including white blood-cell [WBC] count, C-reactive protein [CRP], and erythrocyte sedimentation rate [ESR]), MRI findings, and serology confirmation of LA or bacterial SA. A total of 87 cases of confirmed LA and 9 cases of SA were identified. The 2 cohorts had substantial clinical overlap with regard to the ability to bear weight, fever, and joint aspirate WBC count. Differences between the 2 groups in several MRI characteristics, specifically vastus lateralis myositis, subcutaneous edema, and lymphadenopathy, were significant. A multivariate analysis demonstrated that weight-bearing, CRP of <3 mg/L, absence of subcutaneous edema, myositis of multiple muscles including the vastus lateralis, and lymphadenopathy were predictive of LA. LA should be strongly suspected in endemic areas of the United States when children present with a knee effusion. The addition of MRI criteria to clinical and laboratory findings significantly improved the predictive value for identifying LA. Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Using a decision tool to evaluate for osteomyelitis in children.

Osteomyelitis is a common occurrence in children and typically has a prolonged treatment course involving multiple specialties. Historically, the long bones are most commonly affected and Staphylococcus aureus is the primary causative organism.This case shows the value of using the Kocher criteria and acute phase reactant C-reactive protein as diagnostic tools that can be used to advocate MRI to rule out this potentially devastating process.

Can predictors of Pediatric Septic Hip be applied to the Knee

Purpose: The early diagnosis and treatment of septic arthritis in pediatric patients are paramount to the prevention of long-term sequela. While much of the literature has focused on markers of the hip, little is known of the application of these to the knee. The purpose of this study is to investigate if the Kocher criteria can be used for screening children suspicious to have septic arthritis of the knee. Methods: We retrospectively reviewed the charts of male and …

Characteristics of Pyogenic Musculoskeletal Infections in Older Children and Adolescents.

The characteristics and clinical consequences of pyogenic bone and joint infections in older children and adolescents have received little attention. This study evaluated the presentation and complications of musculoskeletal infections involving the pelvis and extremities in children older than 10 years. Thirty patients 10 to 17 years old (mean, 12.7 years old) were treated for musculoskeletal infections. Mean time to diagnosis was 9.2 days. Prior to correct diagnosis, 83% were assessed by at least 1 outpatient provider. At the time of admission, 55% were weight bearing and 93% were afebrile. Twenty-eight percent had a multifocal infection. More than one-third had serious medical complications or orthopedic sequelae; compared with patients without complications, this group had a significantly higher admission C-reactive protein and longer hospital stay. Symptoms of musculoskeletal infection common among young children may be absent in adolescents. Axial imaging is recommended to identify adjacent or multifocal disease. The Kocher criteria are less sensitive for septic hip arthritis in the adolescent population. Prompt recognition and treatment are critical to avoid medical and musculoskeletal complications. [Orthopedics. 2020;43(4):e291-e298.].

Pediatric Septic Arthritis of the Knee: Predictors of Septic Hip Do Not Apply

The early diagnosis of pediatric septic arthritis is paramount to the prevention of long-term sequela. The purpose of this study is to investigate if the commonly used criteria developed by Kocher and colleagues for hip septic arthritis can be used for screening children with suspected septic knee. We retrospectively reviewed the charts of patients under the age of 19, between June 2002 to June 2017, who presented to a major tertiary-care children's hospital with septic knee. Diagnostic criteria included either a positive synovial culture from the knee, synovial white blood cell (WBC)>50,000 cells/mm, or synovial WBC count >25,000 cells/mm and clinical agreement of diagnosis from Infectious Disease and Orthopaedic colleagues. Collected data included the initial criteria described by Kocher and colleagues: history of fever, non-weight-bearing, erythrocyte sedimentation rate, and serum WBC as well as a recently modified criterion: C-reactive protein. Univariate analysis was used to determine the quality of these variables in ruling out septic knee. One hundred four patient charts were found to meet our inclusion criteria demonstrating C-reactive protein>20 mg/L (75%), fever (65%), non-weight-bearing status (64%), erythrocyte sedimentation rate>40 mm/h (60%), and WBC>12,000 cells/mm (49%). With the 25 different combinations of these predictors adjusted for, in an escalating manner, 0 predictors suggested a sensitivity of 0.02, 1 predictor a sensitivity of 0.06, 2 predictors a sensitivity of 0.2, 3 predictors a sensitivity of 0.32, 4 predictors a sensitivity of 0.3, and 5 predictors a sensitivity of 0.11. According to the Kocher criteria of the hip, at 3 or more criteria the probability of septic arthritis becomes 93% with a sensitivity of 0.84 provoking many physicians to use this cutoff in their assessment of hip pain. This study suggests that if these criteria were applied to the knee, 52% of septic knee cases could be missed. There is a need for further investigation of specific criteria of the knee as the markers of the hip septic arthritis are not necessarily applicable in the knee. Level III.

CD64: An adjunct to Kocher's criteria to differentiate septic arthritis and transient synovitis in children

CD64: An adjunct to Kocher's criteria to differentiate septic arthritis and transient synovitis in children

Pelvic pyomyositis in children: changing trends in occurrence and management.

We present the largest series of paediatric pelvic pyomyositis from a temperate country, analyse the factors influencing long term prognosis and suggest a diagnostic protocol. We included 41 patients diagnosed with primary paediatric pelvic pyomyositis between 1998 and 2016, in this study with a mean age of 7.5years. Demographic, clinical, radiological and follow-up data were reviewed. Statistical analysis was performed to analyse the influence of early diagnosis and treatment on the final outcome. There was an increased occurrence of primary pelvic pyomyositis in the last two years. Of cases identified, 85% fulfilled Kocher's criteria for hip septic arthritis. The mean time to diagnosis was 2.8 ± 0.8days. The most common muscle affected was obturator internus (65.85%) and multifocal involvement was common (46.34%). Early diagnosis and antibiotic treatment within sevendays from the time of onset of symptoms was the only factor that influenced final outcome (p < 0.001). Pyomyositis is no longer restricted to tropical countries. The time from onset of symptoms to start of antibiotic treatment influences the final outcome. Clinical examination and inflammatory markers have low specificity in distinguishing between pyomyositis, septic arthritis, osteomyelitis or other infections. MRI is more sensitive and can diagnose pyomyositis in its early stages. Every suspected case of septic arthritis of the hip should undergo an ultrasound. MRI scan may be performed if the ultrasound shows inconclusive evidence of an effusion. Early identification will facilitate early antibiotic treatment which will improve the final outcome. There is an increasing occurrence of this tropical disease in temperate countries. Early diagnosis with an MRI scan and early antibiotic use results in good outcomes.

Predictors of Septic Arthritis in the Adult Population

Septic arthritis is a devastating condition; well-established criteria for diagnosis exist in the pediatric population, but not for adults. This study evaluated patient factors and laboratory parameters that may be associated with the diagnosis of septic arthritis in adults. A total of 458 knee aspirates for suspected septic arthritis were evaluated with serum and synovial leukocyte counts and differentials as well as Kocher criteria for pediatric septic arthritis. Twenty-two patients (4.8%) had septic arthritis confirmed by a positive synovial fluid culture. Erythrocyte sedimentation rate (ESR) and serum white blood cell (WBC) counts were not statistically different between the 2 groups, with 64% of septic arthritis patients having a normal serum WBC count and 77% being afebrile. Mean synovial fluid WBC count was 26,758 cells/µL and 70,581 cells/µL in the nonseptic and septic groups, respectively. The likelihood ratio for a synovial fluid WBC count greater than 65,000 cells/µL was 2.8 (95% confidence interval, 1.2-6.7). Evaluation receiver operating characteristic curves using synovial WBC counts resulted in a significant area under the curve of 0.66 (P=.02). To achieve 90% specificity, a WBC cutoff of 64,000 cells/µL was required with a corresponding sensitivity of 40%. There was no significant difference in the synovial cell differential of 80% vs 90% in diagnosing infection. Synovial fluid WBC count greater than 64,000 cells/µL yielded the optimal combination of sensitivity and specificity. Polymorphonuclear leukocytes, ESR, serum WBC count, fever, and weight-bearing status were not significant predictors of septic arthritis. This study demonstrates the limited utility of Kocher criteria in the adult population and the importance of synovial leukocyte counts. [Orthopedics. 2016; 39(4):e657-e663.].

Differentiating Transient Synovitis of the Hip from More Urgent Conditions

A variety of traumatic and infectious processes can cause acute onset of hip pain and difficulty walking. Without a history of trauma, a common cause is transient (or "toxic") synovitis, but serious infectious causes, such as septic arthritis of the hip or osteomyelitis, must be ruled out. Differentiating between septic arthritis of the hip (a true emergency) and transient synovitis of the hip (a much more benign inflammatory process) can be difficult. The Kocher criteria have proven to be helpful in making the distinction between these two conditions, and they are reviewed in this article. In addition, imaging studies, especially hip ultrasound, are extremely helpful in the evaluation of the painful hip. [Pediatr Ann. 2016;45(6):e209-e213.].

The limping child.

Limping is a symptom of varied diagnoses in children and adolescents and can present a difficult diagnostic challenge for primary care clinicians. A careful and systematic evaluation can shorten the long list of potential diagnoses to direct appropriate diagnostic tests to determine the cause of the problem. Trauma and infections are the most common causes of limping. Inflammatory conditions, developmental diagnoses,and overuse injuries are other causes. Although rare, malignancies such as osteosarcoma and blood cell cancers must also be considered as potential causes of limping in children and adolescents.• Limping presents a diagnostic challenge due to the number of possible causes.• On the basis of consensus, diagnostic laboratory tests that include complete blood count, erythrocyte sedimentation rate,C-reactive protein, and blood cultures should be ordered if suspicion is high for infectious etiology.• On the basis of consensus, orthopedic emergencies are vascular compromise, compartment syndrome, and open fractures.• On the basis of moderate evidence and consensus, compartment syndrome in children presents with the three "As" analgesia,anxiety, and agitation. (4)• On the basis of strong evidence and consensus, septic arthritis asa diagnosis increases with the number of Kocher criteria present(temperature >38.5°C, white blood cell count >12,000/mL[12109/L], erythrocyte sedimentation rate >40 mm/h, and inability to bear weight). (8)• On the basis of moderate evidence and consensus, laboratory studies are not always definitive for diagnosis of juvenile idiopathic arthritis. (13)• On the basis of consensus, it is always important to examine the joint above and the joint below the area of the chief compliant,specifically when looking at slipped capital femoral epiphysis and Legg-Calvé-Perthes disease.

Lyme arthritis of the pediatric lower extremity in the setting of polyarticular disease.

BackgroundLyme arthritis can be readily treated with use of oral antibiotics without any need for surgery. In Lyme-endemic areas, differentiating between Lyme arthritis and septic arthritis can be difficult. Laboratory testing for Lyme disease often results in a delay in diagnosis because many labs batch-test Lyme specimens only two times per week due to lack of equipment or increased expense. Delayed diagnosis can lead to unneeded surgery in cases in which the surgeon indicates the patient for a joint irrigation and debridement (I & D) for possible septic arthritis while waiting for Lyme serology results. The purpose of this study was to develop an algorithm for the treatment of patients with possible Lyme arthritis, with particular attention to poly-articular involvement.MethodsThirty-nine patients with poly-articular Lyme arthritis, including ankle involvement, were reviewed retrospectively. Patients were included if the ankle was involved, if they were less than 18 years of age, and had available laboratory information and a serologic diagnosis of Lyme disease.ResultsOnly two patients had isolated ankle involvement; of those with poly-articular involvement, 34 patients had ankle/knee involvement. Nine patients presented with pain in the ankle with passive range of motion (PROM) (22 %); two (4.8 %) had refusal to bear weight, and 10 (24 %) had an antalgic gait. All patients had a positive Western blot. Ten patients had a peripheral white blood cell (WBC) count >12,500/mm3 , and 16 patients had an erythrocyte sedimentation rate (ESR) >40 mm/h.ConclusionWithout immediate availability of Lyme serology, the decision to perform surgical drainage of a swollen joint in the setting of possible Lyme arthritis versus septic bacterial arthritis remains a clinical dilemma. Our data suggests that patients presenting with one or fewer Kocher criteria symptoms, poly-articular disease, and minimal pain with PROM have Lyme, rather than septic, arthritis. These patients can be treated with joint aspiration for cultures, appropriate antibiotics for Lyme disease, and careful serial exams while waiting for results of Lyme serology rather than immediate surgical I & D.

Comparison of Bacteriologically Proven Septic Arthritis of the Hip and Knee in Children, a Preliminary Study

The hip and knee are the commonest joints affected by septic arthritis in the pediatric age group. Both can present as a limping, unwell child and can be difficult to diagnose. The primary aim of this study is to review and compare characteristics of pediatric patients with culture positive septic arthritis of the hip to those with culture positive septic arthritis of the knee. We retrospectively reviewed all patients who were clinically diagnosed with acute septic arthritis of either hip or knee in a tertiary pediatric hospital for a period of 3 years. Twelve of 29 patients who underwent arthrotomy for presumed septic arthritis of the hip and 7 of 37 patients who underwent arthrotomy for presumed septic arthritis of the knee had positive joint cultures. Patients with septic arthritis of the knee were much younger than that with septic arthritis of the hip. Patients with presumed septic arthritis of the knee based on clinical picture were less likely to have a positive synovial fluid culture. Children with septic arthritis of the knee did not follow Kocher criteria in the same way that children with septic arthritis of the hip did.