Risk factors for perioperative hyperglycemia in primary hip and knee replacements

Background and purpose — Perioperative hyperglycemia has been associated with adverse outcomes in several fields of surgery. In this observational study, we identified factors associated with an increased risk of hyperglycemia following hip and knee replacement.

Patients and methods — We prospectively monitored changes in glucose following primary hip and knee replacements in 191 patients with osteoarthritis. Possible associations of patient characteristics and operation-related factors with hyperglycemia (defined as glucose > 7.8 mmol/L in 2 consecutive measurements) and severe hyperglycemia (glucose > 10 mmol/L) were analyzed using binary logistic regression with adjustment for age, sex, operated joint, and anesthesiological risk score.

Results — 76 patients (40%) developed hyperglycemia, and 48 of them (25% of the whole cohort) had severe hyperglycemia. Glycemic responses were similar following hip replacement and knee replacement. Previously diagnosed diabetes was associated with an increased risk of hyperglycemia and severe hyperglycemia, compared to patients with normal glucose metabolism, whereas newly diagnosed diabetes and milder glucose metabolism disorders had no effect. In patients without previously diagnosed diabetes, increased values of preoperative glycosylated hemoglobin (HbA1c) and fasting glucose on the day of operation were associated with hyperglycemia. Higher anesthesiological risk score—but none of the operation-related factors analyzed—was associated with an increased risk of hyperglycemia.

Interpretation — Perioperative hyperglycemia is common in primary hip and knee replacements. Previously diagnosed diabetes is the strongest risk factor for hyperglycemia. In patients with no history of diabetes, preoperative HbA1c and fasting glucose on the day of operation can be used to stratify the risk of hyperglycemia.     

Body mass index and risk of perioperative cardiovascular adverse events and mortality in 34,744 Danish patients undergoing hip or knee replacement

Background and purpose — Obesity is a risk factor for osteoarthritis in the lower limb, yet the cardiovascular risks associated with obesity in hip or knee replacement surgery are unknown. We examined associations between body mass index (BMI) and the risk of a major adverse cardiovascular event (MACE: ischemic stroke, acute myocardial infarction, or cardiovascular death) or the risk of all-cause mortality in a nationwide Danish cohort of patients who underwent primary hip or knee replacement surgery.

Methods — Using Danish nationwide registries, we identified 34,744 patients aged ≥ 20 years who underwent elective primary hip or knee replacement surgery between 2005 and 2011. We used multivariable Cox regression models to calculate the 30-day risks of MACE and mortality associated with 5 BMI groups (underweight (BMI < 18.5 kg/m²), normal weight (18.5–24 kg/m²), overweight (25–29 kg/m²), obese 1 (30–34 kg/m²), and obese 2 (≥ 35 kg/m²)).

Results — In total, 232 patients (0.7%) had a MACE and 111 (0.3%) died. Compared with overweight, adjusted hazard ratios (HRs) were 1.2 (95% CI: 0.4–3.3), 1.3 (0.95–1.8), 1.6 (1.1–2.2), and 1.0 (0.6–1.9) for underweight, normal weight, obese 1, and obese 2 regarding MACE. Regarding mortality, the corresponding HRs were 7.0 (2.8–15), 2.0 (1.2–3.2), 1.5 (0.9–2.7), and 1.9 (0.9–4.2). Cubic splines suggested a significant U-shaped relationship between BMI and risks with nadir around 27–28.

Interpretation — In an unselected cohort of patients undergoing elective primary hip or knee replacement surgery, U-shaped risks of perioperative MACE and mortality were found in relation to BMI. Patients within the extreme ranges of BMI may warrant further attention.     

Pre-operative interventions (non-surgical and non-pharmacological) for patients with hip or knee osteoarthritis awaiting joint replacement surgery--a systematic review and meta-analysis

Objective

To determine if pre-operative interventions for hip and knee osteoarthritis provide benefit before and after joint replacement.

Method

Systematic review with meta-analysis of randomised controlled trials (RCTs) of pre-operative interventions for people with hip or knee osteoarthritis awaiting joint replacement surgery.Standardised mean differences (SMD) were calculated for pain, musculoskeletal impairment, activity limitation, quality of life, and health service utilisation (length of stay and discharge destination). The GRADE approach was used to determine the quality of the evidence.

Results

Twenty-three RCTs involving 1461 participants awaiting hip or knee replacement surgery were identified. Meta-analysis provided moderate quality evidence that pre-operative exercise interventions for knee osteoarthritis reduced pain prior to knee replacement surgery (SMD (95% CI) = 0.43 [0.13, 0.73]). None of the other meta-analyses investigating pre-operative interventions for knee osteoarthritis demonstrated any effect. Meta-analyses provided low to moderate quality evidence that exercise interventions for hip osteoarthritis reduced pain (SMD (95% CI) = 0.52 [0.04, 1.01]) and improved activity (SMD (95% CI) = 0.47 [0.11, 0.83]) prior to hip replacement surgery. Meta-analyses provided low quality evidence that exercise with education programs improved activity after hip replacement with reduced time to reach functional milestones during hospital stay (e.g., SMD (95% CI) = 0.50 [0.10, 0.90] for first day walking).

Conclusion

Low to moderate evidence from mostly small RCTs demonstrated that pre-operative interventions, particularly exercise, reduce pain for patients with hip and knee osteoarthritis prior to joint replacement, and exercise with education programs may improve activity after hip replacement.     

Pain threshold correlates with functional scores in osteoarthritis patients

Background and purpose — Pain sensitization may be one of the reasons for persistent pain after technically successful joint replacement. We analyzed how pain sensitization, as measured by quantitative sensory testing, relates preoperatively to joint function in patients with osteoarthritis (OA) scheduled for joint replacement.

Patients and methods — We included 50 patients with knee OA and 49 with hip OA who were scheduled for joint replacement, and 15 control participants. Hip/knee scores, thermal and pressure detection, and pain thresholds were examined.

Results — Median pressure pain thresholds were lower in patients than in control subjects: 4.0 (range: 0–10) vs. 7.8 (4–10) (p = 0.003) for the affected knee; 4.5 (2–10) vs. 6.8 (4–10) (p = 0.03) for the affected hip. Lower pressure pain threshold values were found at the affected joint in 26 of the 50 patients with knee OA and in 17 of the 49 patients with hip OA. The American Knee Society score 1 and 2, the Oxford knee score, and functional questionnaire of Hannover for osteoarthritis score correlated with the pressure pain thresholds in patients with knee OA. Also, Harris hip score and the functional questionnaire of Hannover for osteoarthritis score correlated with the cold detection threshold in patients with hip OA.

Interpretation — Quantitative sensory testing appeared to identify patients with sensory changes indicative of mechanisms of central sensitization. These patients may require additional pain treatment in order to profit fully from surgery. There were correlations between the clinical scores and the level of sensitization.     

Effectiveness of hip or knee replacement surgery in terms of quality-adjusted life years and costs

Background?Concurrent head-to-head comparisons of healthcare interventions regarding cost-utility are rare. The concept of favorable cost-effectiveness of total hip or knee arthroplasty is thus inadequately verified.

Patients and methods?In a trial involving several thousand patients from 10 medical specialties, 223 patients who were enrolled for hip or knee replacement surgery were asked to fill in the 15D health-related quality of life (HRQoL) survey before and after operation.

Results?Mean (SD) HRQoL score (on a 0–1 scale) increased in primary hip replacement patients (n = 96) from 0.81 (0.084) preoperatively to 0.86 (0.12) at 12 months (p < 0.001). In revision hip replacement (n = 24) the corresponding scores were 0.81 (0.086) and 0.82 (0.097) respectively (p = 0.4), and in knee replacement (n = 103) the scores were 0.81 (0.093) and 0.84 (0.11) respectively (p < 0.001). Of 15 health dimensions, there were statistically significant improvements in moving, usual activities, discomfort and symptoms, distress, and vitality in both primary replacement groups. Mean cost per quality-adjusted life year (QALY) gained during a 1-year period was € 6,710 for primary hip replacement, € 52,274 for revision hip replacement, and € 13,995 for primary knee replacement.

Interpretation?Hip and knee replacement both improve HRQoL. The cost per QALY gained from knee replacement is twice that gained from hip replacement.     

髋关节置换术治疗髋部疾病合并帕金森病的疗效分析

目的 :探讨髋关节置换术在髋部疾病合并帕金森病患者中的临床疗效进行分析。方法 :自2011年12月至2016年12月,回顾性分析采用髋关节置换术治疗18例髋部疾病合并帕金森疾病的患者,男8例,女10例;年龄59~87岁,平均71岁。其中3例为发育性髋关节发育不良,3例为股骨头坏死,12例为股骨颈骨折。患者术前均有明显疼痛,行走能力受限。观察患者术后并发症情况,并采用Harris评分比较手术前后髋关节功能变化。结果:术后患者伤口愈合良好,疼痛均较术前明显减轻或消失,髋关节功能明显改善。18例患者均获得随访,时间1~3年,平均2.3年。末次随访时,14例恢复自由行走,2例需要手杖帮助下行走,1例助行器协助行走,1例死亡。18例中,2例出现脱位,其中1例脱位患者于术后3个月因心肺疾病死亡,此外,有4例活动后出现轻微疼痛。术前Harris评分(41.7±1.4)分别与术后6个月(80.1±5.4)和末次随访(83.4±2.1)比较差异有统计学意义(P0.05),其中优10例,良4例,可1例,差2例。结论:人工关节置换术在髋部疾病合并帕金森病患者中的应用是一种安全有效的治疗方法,具有并发症少、功能恢复快的优点。     

Abnormal loading of the hip and knee joints in unilateral hip osteoarthritis persists two years after total hip replacement

A total hip replacement (THR) is a common and routine procedure to reduce pain and restore normal activity. Gait analysis can provide insights into functional characteristics and dynamic joint loading situation not identifiable by clinical examination or static radiographic measures. The present prospective longitudinal study tested whether 2 years after surgery a THR would restore dynamic loading of the knee and hip joints in the frontal plane to normal. Instrumented gait analysis was performed shortly before surgery and approximately 2 years after THR on 15 unilateral hip osteoarthritis (OA) patients. 15 asymptomatic matched individuals were recruited as healthy controls. Results showed that abnormal joint loading persisted 2 years after THR. The 2nd external knee adduction moment in terminal stance in the affected (?34%, p = 0.002, d = 1.22) and non‐affected limb (?25%, p = 0.035, d = 0.81) was lower compared to controls and thus indicated a shift in the knee joint load distribution from medial to lateral. A correlation analysis revealed that a smaller hip range of motion explained 46% of 2nd knee adduction moment alterations. In contrast, the 2nd external hip adduction moment in terminal stance was postoperatively higher in the affected (+22%, p = 0.007, d = 1.04) and non‐affected limb (+22%, p = 0.005, d = 1.05). Here, 51% of 2nd hip adduction moment alterations can be explained with a greater hip adduction angle. Patients with a THR may therefore be at higher risk for abnormal joint loading and thus for the development of OA in other joints of the lower extremities. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2167–2177, 2018.

     

台湾地区人工髋与膝关节首次置换与翻修术的对比分析

目的探讨华人的人工髋与膝关节手术的置换与翻修术的分布情形。方法本研究通过1996～2004年台湾健康保险局数据库中人工髋与膝关节的手术资料共186084例,包括169310例首次置换以及16774例翻修手术的数据。结果因髋关节疾病而进行首次置换的发生率较膝关节疾病稍高（2004年每十万人发生率为55．94比54．17）。全髋关节置换术在45～65岁年龄层最多占40％;半髋关节置换术在75岁以上年龄层占54％;全膝关节置换术在65岁以上年龄层占73％。首次人工髋与膝关节手术平均每年花费分别为3400万与3600万美金。结论本研究结果除了显示台湾每年人工髋与膝关节手术量以及翻修手术的数量逐年增加,也显示华人的关节适应证与好发年龄层与白种人是有所差异的。     

Comparison of gender and group differences in self-report and physical performance measures in total hip and knee arthroplasty candidates.

Functional measures (fast self-paced walk test, stair climb, and timed up and go) and a self-report measure of function (Lower Extremity Activity Profile) were assessed in 1,805 total hip (761) and knee (1044) arthroplasty candidates (1,063 women, 742 men) preoperatively. Women represented 59% of the study subjects and showed greater disability than men (P 相似文献   

Outcomes following hip and knee replacement in diabetic versus nondiabetic patients and well versus poorly controlled diabetic patients: a prospective cohort study

Background and purpose — The impact of diabetes and glycemic control before joint replacement on clinical and patient-reported outcomes is unclear. We compared pain, function, complications, and length of hospital stay in diabetic and nondiabetic patients receiving primary total hip (THR) or knee replacement (TKR) and compared these outcomes in patients with poorly controlled versus well-controlled diabetes.

Patients and methods — We conducted a prospective cohort study of patients undergoing primary THR (n = 300) or TKR (n = 287) for osteoarthritis. Self-reported diabetes and glycemic control (HbA1c?≤?or >7%) extracted from medical notes were used. Adjusted comparisons were performed with generalized linear models including body mass index (BMI) and comorbidities.

Results — Diabetes prevalence was 11% (THR 8%; TKR 14%). Diabetic patients were more likely to have a higher BMI and greater number of comorbidities. The median length of hospital stay was 1?day longer in diabetic patients (p = 0.004), but this attenuated after adjustments for BMI and comorbidities (p = 0.3). Inpatient pain was greater for diabetic patients but attenuated following adjustment. The 12-month postoperative WOMAC subscales were similar by diabetes status following adjustment. There was little evidence of difference in outcomes according to glycemic control.

Interpretation — The associations between diabetes and worse postoperative outcomes in patients undergoing THR or TKR for osteoarthritis appear to be predominantly due to associated obesity and comorbidities. In diabetic patients there is little evidence of association between postoperative outcome and preoperative glycemic control. The underlying mechanisms and causal pathways of obesity, diabetes, and multimorbidity that lead to worse outcomes after joint replacement are not well known.     

Decision regret after primary hip and knee replacement surgery

BackgroundDecision regret (DR) is a recognised patient centered outcome measure following a therapeutic intervention. This study aimed to measure DR following primary total hip and knee arthroplasty (THA/TKA), to assess for differences between these patients and explore possible contributory factors.MethodDR was measured using the DR scale in a group of THA and TKA patients, between February 2017 and December 2018, who had made a decision to have joint replacement surgery within the previous year and were able to reflect on their outcomes.ResultsOn analysis a significantly greater proportion of TKA patients reported moderate or severe (Mod/Sev) DR [17.1% (56/328)] compared to THA patients [4.8% (18/376)]. Conversely, a significantly reduced proportion of TKA patients reported having No DR [42.1% (138/328)] compared to THA patients [66.7% (251/376)]. On multivariate logistic regression analysis joint replacement type (TKA/THA) and change in Oxford score were significant predictors of DR with gender, age, BMI and ASA grade not significantly associated. TKA patients were more than twice as likely to have Mod/Sev DR compared THA patients (Odds Ratio = 2.33 (95% CI 1.24–4.39)). Patients with poorer improvements in pain and function 1-year post-operatively (measured by Oxford scores) reported greater levels of DR.ConclusionTKA patients were significantly more likely to report greater levels of DR 1-year following surgery compared to THA patients. For both TKA and THA patients, greater levels of DR were associated with poorer Oxford scores. The use of decision aids to reduce post-operative DR in joint replacement patients should be examined especially for knee replacement patients.     

Diabetes is associated with persistent pain after hip and knee replacement

Background and purpose

In some patients, for unknown reasons pain persists after joint replacement, especially in the knee. We determined the prevalence of persistent pain following primary hip or knee replacement and its association with disorders of glucose metabolism, metabolic syndrome (MetS), and obesity.

Patients and methods

The incidence of pain in the operated joint was surveyed 1–2 years after primary hip replacement (74 patients (4 bilateral)) or primary knee replacement (119 patients (19 bilateral)) in 193 osteoarthritis patients who had participated in a prospective study on perioperative hyperglycemia. Of the 155 patients who completed the survey, 21 had undergone further joint replacement surgery during the follow-up and were excluded, leaving 134 patients for analysis. Persistent pain was defined as daily pain in the operated joint that had lasted over 3 months. Factors associated with persistent pain were evaluated using binary logistic regression with adjustment for age, sex, and operated joint.

Results

49 of the134 patients (37%) had a painful joint and 18 of them (14%) had persistent pain. A greater proportion of knee patients than hip patients had a painful joint (46% vs. 24%; p = 0.01) and persistent pain (20% vs. 4%; p = 0.007). Previously diagnosed diabetes was strongly associated with persistent pain (5/19 vs. 13/115 in those without; adjusted OR = 8, 95% CI: 2–38) whereas MetS and obesity were not. However, severely obese patients (BMI ≥ 35) had a painful joint (but not persistent pain) more often than patients with BMI < 30 (14/21 vs. 18/71; adjusted OR = 5, 95% CI: 2–15).

Interpretation

Previously diagnosed diabetes is a risk factor for persistent pain in the operated joint 1–2 years after primary hip or knee replacement.Many patients continue to experience pain after joint replacement. Persistent pain is defined as pain that develops after surgery and that has been present for over 3 months (International Association for the Study of Pain 1986) and its prevalence is underestimated (Visser 2006). According to Beswick et al. (2012), at least 5–21% of hip replacement recipients and 8–27% of knee replacement recipients suffer from persistent pain postoperatively.Persistent pain is generally thought to be of neuropathic origin and caused by perioperative nerve damage (Kehlet et al. 2006). However, neuropathic pain appears to be rare in joint replacement patients (Wylde et al. 2011). Instead, these patients often describe their pain in a way that indicates the presence of an inflammatory factor (Wylde et al. 2011). The degree of the inflammatory state is associated with the severity of preoperative pain in patients with osteoarthritis (Stürmer et al. 2004). In addition, the intensity and duration of preoperative pain correlates with persistent postoperative pain in knee replacement surgery (Lundblad et al. 2008, Puolakka et al. 2010). Other established risk factors for persistent pain include genetic factors, history of preoperative pain, depression, existence of other chronic pain sites, and psychosocial factors (Kehlet et al. 2006, Nikolajsen et al. 2006, Rolfson et al. 2009).Low-grade systemic inflammation is associated with the pathogenesis of diabetes, metabolic syndrome (MetS; a clustering of cardiovascular risk factors including abdominal obesity, hypertension, dyslipidemia, and impaired glucose metabolism (Alberti et al. 2009)), and obesity. All these conditions are common in joint replacement recipients (Meding et al. 2007, Gonzales Della Valle et al. 2012, Workgroup of the American Association of Hip and Knee Surgeons Evidence Based Committee 2013). Diabetes is associated with poor postoperative outcomes, including reduced joint function (Robertson et al. 2012) and slower recovery in terms of pain and function (Jones et al. 2012). Obesity is associated with slower recovery, especially in knee patients (Workgroup of the American Association of Hip and Knee Surgeons Evidence Based Committee 2013). It has been hypothesized that the systemic proinfammatory state in MetS negatively affects patients’ function and recovery after joint replacement (Gandhi et al. 2010). To our knowledge, the effect of disorders of glucose metabolism, MetS, and obesity on persistent pain after joint replacement has not been studied previously.We therefore determined whether glucose metabolism disorders, MetS, and obesity are associated with persistent pain in the operated joint 1–2 years after primary joint replacement.     

Two cases of late medial instability of the knee due to hip disease after total knee arthroplasty

IntroductionThere are few specific reports of late medial instability after total knee arthroplasty (TKA). We described two cases of late medial instability of the knee due to hip disease with osteoarthritis or rheumatoid arthritis after TKA, which required revision TKA.Presentation of casesAn 82-year-old woman experienced right femoral neck fracture due to a fall that required conservative treatment at age 77 years and underwent left TKA at age 80 years. A 68-year-old woman underwent left TKA at age 54 years, right TKA at age 64 years, and left THA at age 67 years. Both cases required revision TKA with constrained knee prostheses due to the severe medial instability. Hip-knee-ankle (HKA) angle, range of motion (ROM), Knee Society score (KSS) and functional score (FS) were evaluated pre- and postoperatively. Their respective HKA angle improved from 134° and 155° preoperatively to 184° and 179° postoperatively. KSS improved from −4 and 53 points to 59 and 100 points, respectively. FS improved from −10 and 58 points to 25 and 90 points, respectively. In the 82-year-old woman, ROM did not improve from −10–90° to −20–90°. On the other hand, in the 68-year-old woman, ROM improved from 0–110° to 0–125°. The late medial instability in the current case report was partly due to a similar mechanism underlying the long leg arthropathy and coxitis knee caused by hip joint degeneration.ConclusionsConstrained prostheses were applied for both patients, providing moderately good short-term results.     

Comparative analysis of patient-centered outcome of total hip and knee arthroplasty

AIM: The aim of the present study was a comparative investigation of the functional improvement reported by patients suffering from primary osteoarthritis of the knee or hip undergoing total joint replacement and assessed at 3 months. METHOD: In a prospective, controlled clinical trial, 56 patients with primary osteoarthritis of the hip and 59 patients with primary osteoarthritis of the knee undergoing total joint replacement were assessed at two measuring times (day of admission = t1 and 3-month follow-up = t2) using the XSMFA-D (Extra Short Musculoskeletal Function Assessment Questionnaire--German version), WOMAC (Western Ontario and McMasters Universities) arthrosis index and FFb-H OA (Function Assessment Questionnaire Hannover Osteoarthritis). The statistical analysis included effect sizes as standardised response mean, t-test and covariance analysis. RESULTS: Both groups of patients demonstrated significant improvements of the musculoskeletal functions measured. The effect sizes between baseline scores and 3-month follow-up scores range from 0.4 to 2.0 and can be considered as large effects. The covariance analysis showed significant differences between patients with osteoarthritis of the hip and knee for almost every score examined. Patients with hip replacement showed large improvements. A significant influence of the presurgery baseline score on the 3-month score was found consistently. Further analysis showed that patients with medium or strong degrees of disability according to the Function index of the XSMFA-D showed the strongest effects of change at 3 months. However, their scores at t2 were less than the scores of the less disabled patients at t1. CONCLUSION: We conclude that patients with hip replacement show more improvement 3 months after the surgery than patients with knee replacement. Furthermore, it was seen that patients who were more disabled before surgery achieved more improvement than the less-disabled patients. However, they did not achieve the level of the less disabled patients. Thus, the recommendation that total joint replacement should be performed as late as possible should be reviewed.     

Local infiltration analgesia: a technique for the control of acute postoperative pain following knee and hip surgery: A case study of 325 patients

Background?We have developed a multimodal technique for the control of pain following knee and hip surgery, called "local infiltration analgesia" (LIA). It is based on systematic infiltration of a mixture of ropiva-caine, ketorolac, and adrenaline into the tissues around the surgical field to achieve satisfactory pain control with little physiological disturbance. The technique allows virtually immediate mobilization and earlier discharge from hospital.

Patients and methods?In this open, nonrandomized case series, we used LIA to manage postoperative pain in all 325 patients presenting to our service from Jan 1, 2005 to Dec 31,2006 for elective hip resurfacing (HRA), primary total hip replacement (THR), or primary total knee replacement arthroplasty (TKR). We recorded pain scores, mobilization times, and morphine usage for the entire group.

Results?Pain control was generally satisfactory (numerical rating scale pain score range 0–3). No morphine was required for postoperative pain control in two-thirds of the patients. Most patients were able to walk with assistance between 5 and 6 h after surgery and independent mobility was achieved 13–22 h after surgery. Orthostatic hypotension, nausea, and vomiting were occasionally associated with standing for the first time, but other side effects were unremarkable. 230 (71%) of the 325 patients were discharged directly home after a single overnight stay in hospital.

Interpretation?Local infiltration analgesia is simple, practical, safe, and effective for pain management after knee and hip surgery.     

Effects of changes in whole-body alignment on ipsilateral knee pain after total hip arthroplasty

BackgroundTotal hip arthroplasty decreases hip pain and often reduces knee pain in patients with hip osteoarthritis. Whole-body alignment may be associated with knee pain, but to our knowledge this relationship has not been previously investigated. The purpose of this study was to investigate the effect of changes in whole-body alignment on ipsilateral knee pain in patients after total hip arthroplasty.MethodsIn total, 94 patients with unilateral hip osteoarthritis who underwent total hip arthroplasty were enrolled in this study. A visual analog scale (VAS) was used to investigate perioperative knee pain. An EOS 2D/3D X-ray system was used to quantify the whole-body alignment of the spine, pelvis, and lower extremities in the standing position. The relationship between perioperative changes in knee pain and whole-body alignment was investigated.ResultsAmong 61 patients who had preoperative ipsilateral knee pain, pain resolved in 30 (50%) and persisted in 31 (50%) after surgery. In these patients, average ipsilateral knee pain decreased significantly after surgery, from 41 mm to 14 mm on the VAS (P < 0.01). Preoperative knee pain was correlated with femorotibial rotation, and postoperative knee pain was correlated with K-L grade, preoperative knee pain visualized analog scale, and preoperative sagittal vertical axis. Multiple linear regression identified preoperative sagittal vertical axis as significantly associated with residual postoperative ipsilateral knee pain.ConclusionsIpsilateral knee pain decreased in half of patients after total hip arthroplasty. Patients with a considerable forward-bent posture may have residual ipsilateral knee pain after total hip arthroplasty.     

The KHOALA cohort of knee and hip osteoarthritis in France

ObjectivesThis study aimed to describe the prevalence of symptomatic knee and hip osteoarthritis (OA) and its course over time, as well as identify prognostic factors of OA course and determinants of costs and access to care in France in a patient cohort.MethodsSubjects aged 40 to 75 years, with uni- or bilateral symptomatic hip and/or knee OA (ACR criteria), Kellgren and Lawrence (KL) stage 2 or greater, were recruited from a French national prevalence survey for the multicenter KHOALA cohort study. Data collected at baseline included sociodemographic and clinical data; WOMAC, IKS and Harris scores for pain and function; MAQ score for physical activity; functional comorbidity index; GHQ28 score for psychological status; and SF-36 (generic) and OAKHQOL (specific) scores for quality of life. Blood and urine samples were collected.ResultsEight hundred and seventy-eight subjects were included, 222 with OA of the hip (mean age 61.2 ± 8.8 years), 607 knee (mean age 62.0 ± 8.5 years) and 49 both hip and knee (mean age 64.9 ± 7.9 years). Mean body mass index was 26.9 ± 4.5 for hip OA and 30.3 ± 6.3 for knee OA. Hip and knee OA patients had 1.99 and 2.06 comorbidities, on average, respectively. Disease severity on X-rays for KL stages 2, 3 and 4 for hip OA was 69.8, 26.1 and 4.1%, respectively, and for knee OA, 44.5, 30.3, and 25.2%. As compared with population norms, age- and sex-standardized SF-36 scores were greatly decreased for both knee and hip OA in all dimensions, particularly physical and emotional dimensions.PerspectivesPatients will be followed up annually, alternately by mail and clinical visit. This cohort of representative patients with knee and hip OA will be an opportunity for future collaborative research.     

Impulse-forces during walking are not increased in patients with knee osteoarthritis

Background?Impulsive forces in the knee joint have been suspected to be a co-factor in the development and progression of knee osteoarthritis. We thus evaluated the impulsive sagittal ground reaction forces (iGRF), shock waves and lower extremity joint kinematics at heel strike during walking in knee osteoarthritis (OA) patients and compared them to those in healthy subjects.

Subjects and methods?We studied 9 OA patients and 10 healthy subjects using three-dimensional gait analyses concentrated on the heel strike. Impulse GRF (iGRF) was measured together with peak accelerations (PA) at the tibial tuberosity and sacrum. Sagittal lower extremity joint angles at heel strike were extracted from the gait analyses. As OA is painful and pain might alter movement strategies, the patient group was also evaluated following pain relief by intraarticular lidocaine injections.

Results?The two groups showed similar iGRF, similar tibial and sacral PA, and similar joint angles at heel strike. Following pain relief, the OA patients struck the ground with more extended hip and knee joints and lower tibial PA compared to the painful condition. Although such changes occurred after pain relief, all parameters were within their normal ranges.

Interpretation?OA patients and healthy subjects show similar impulse-forces and joint kinematics at heel strike. Following pain relief in the patient group, changes in tibial PA and in hip and knee joint angles were observed but these were still within the normal range. Our findings make us question the hypothesis that impulse-forces generated at heel strike during walking contribute to progression of OA.     

Neonatal hip instability and risk of total hip replacement in young adulthood

Background and purpose Dysplasia is probably the most common underlying condition in osteoarthritis of the hip, leading to total hip replacement (THR) in young adulthood. We investigated whether hip instability at birth predisposes to THR in young adulthood.

Methods Since 1967, all newborns in Norway have been screened for neonatal hip instability (NHI) and the results have been reported to the Medical Birth Registry of Norway (MBRN). In the period 1967-2004,2,218,596 newborns were registered. From 1987 to 2004, 442 of these individuals had been reported to the Norwegian Arthroplasty Register (NAR) after undergoing total hip replacement (mean age 25 (12-36) years).

Results Neonatal hip instability was reported in 19,432 newborns (0.88%) in the MBRN; according to the NAR, they had a 2.6 (CI 1.4-4.8) times increased risk of THR in young adulthood compared to those without NHI. The absolute risk was low, however; only 57 (95% CI: 30-105) in 10⁵ for patients with NHI compared to 20 (95% CI: 18-22) in 10⁵ for those without registered hip pathology. Of the 442 patients with THR, 95 were operated because of osteoarthritis of the hip secondary to dysplasia, according to the surgeon's report. However, only 8 of these 95 patients had been reported to have hip instability at birth.

Interpretation Neonatal hip instability increases the risk of THR in young adulthood. Unexpectedly, only 8% of those who underwent THR due to dysplasia were reported to have unstable hips at birth. Our results indicate that clinical testing for NHI is insufficient as a screening method for dysplastic hips that require THR in young adulthood.