Hip kinematics and kinetics in patients with femoroacetabular impingement syndrome before and 1 year after hip arthroscopic surgery. Results from the HAFAI cohort.

INTRODUCTION: Patients with femoroacetabular impingement syndrome (FAIS) experience decreased function. Consequently, earlier studies have evaluated gait biomechanics in these patients, but a larger study evaluating gait biomechanics before and after an intervention standardising gait speed is lacking. We aimed at investigating gait kinematics and kinetics in patients with FAIS compared with pain-free controls before and 1 year after hip arthroscopic surgery. Secondary, we aimed at analysing gait pattern separately for the sexes and to investigate associations between peak kinematics and kinetics and the Copenhagen Hip and Groin Outcome Score (HAGOS). MATERIALS AND METHODS: Sixty patients with FAIS and 30 pain-free controls were tested at a standardised gait speed (1.40 m/s ± 10%). Patients were tested twice: before and 1 year after surgery. Kinematics and kinetics were recorded using infrared high-speed cameras and a force plate. Participants answered HAGOS. RESULTS: The largest difference among groups was that gait differed between males and females. Neither before nor after surgery could we demonstrate large alterations in gait pattern between patients and pain-free controls. Male patients demonstrated associations between peak kinematics and kinetics and HAGOS Sports function. CONCLUSIONS: Gait pattern was only vaguely altered in patients with FAIS compared with pain-free controls before and after surgery when using at standardised gait speed. Hence, analysing gait in patients with FAIS does not seem of major importance. Nevertheless, there was an association between HAGOS Sports function and peak kinematics and kinetics in male patients, implying that there could be a clinical importance.

Weight Loss Intervention Before Total Knee Replacement: A 12-Month Randomized Controlled Trial.

BACKGROUND AND AIMS: Obesity is an increasing problem in patients after total knee replacement. The aim of this study was to investigate whether a weight loss intervention before primary total knee replacement would improve quality of life, knee function, mobility, and body composition 1 year after surgery. MATERIAL AND METHODS: Patients scheduled for total knee replacement due to osteoarthritis of the knee and obesity were randomized to a control group receiving standard care or to an intervention group receiving 8-week low-energy diet before total knee replacement. Patient-reported quality of life, 6-Min Walk Test, and body composition by dual-energy X-ray absorptiometry were assessed before intervention for the diet group, and within 1 week preoperatively for both groups, and the changes in outcome from baseline to 1 year after total knee replacement were compared between groups. The number of participants was lower than planned, which might introduce a type-2 error and underestimate the trend for a better outcome after weight loss. RESULTS: The analyses are based on a total of 76 patients, 38 in each group. This study showed major improvement in both study groups in quality of life and knee function, though no statistically significant differences between the groups were observed 1 year after total knee replacement. The average weight loss after 8-week preoperative intervention was 10.7 kg and consisted of a 6.7 kg reduction in fat mass. One year after total knee replacement, the participants in the diet group managed to maintain the weight reduction, whereas there was no change in the control group. CONCLUSION: The results suggest that it is feasible and safe to implement an intensive weight loss program shortly before total knee replacement. The preoperative intervention resulted in a 10% body weight loss, improved body composition, lower cardiovascular risk factors, and sustained s-leptin.

No association between femoral or acetabular angles and patient-reported outcomes in patients with femoroacetabular impingement syndrome-results from the HAFAI cohort.

Patients with femoroacetabular impingement syndrome (FAIS) are diagnosed using imaging, but detailed description especially the acetabular shape is lacking and may help give more insight to the pathogenesis of FAIS. Furthermore, associations between patient-reported outcomes (PROs) and the radiological angles might highlight which radiological angles affect outcomes experienced by the patients. Hence, the aims of this study were (i) to describe computer tomography (CT) acquired angles in patients with FAIS and (ii) to investigate the association between radiological angles and the Copenhagen Hip and Groin Outcome Score (HAGOS) in patients with FAIS. Patients scheduled for primary hip arthroscopic surgery for FAIS were included. Based on CT, following angles were measured before and 1 year after surgery; femoral anteversion, alpha, lateral centre edge, acetabular index, anterior sector, posterior sector and acetabular anteversion. All patients completed the HAGOS. Sixty patients (63% females) aged 36 ± 9 were included. One year after surgery, significant alterations in the alpha angle and the acetabular index angle were found. Neither baseline PROs nor changes in PROs were associated with the radiological angles or changes in angles. Since neither changes in CT angles nor baseline scores were associated with HAGOS, the improvements felt by patients must origin from somewhere else. These findings further underlines that morphological changes seen at imaging should not be treated arthroscopically without a patient history of symptoms and clinical findings.

18F FDG-PET/CT has poor diagnostic accuracy in diagnosing shoulder PJI.

PURPOSE: Chronic low-grade periprosthetic joint infection (PJI) of a shoulder replacement can be challenging to diagnose. 18F-FDG PET/CT is suggested as a modality to diagnose lower-limb PJI, but no studies on shoulder replacements exist. The aim of this study was therefore to determine the diagnostic accuracy of 18F-FDG PET/CT in diagnosing chronic PJI of the shoulder. METHODS: Patients evaluated for a failed shoulder replacement during a 3-year period were prospectively included in the study. All patients underwent pre-operative 18F-FDG PET/CT, and were evaluated for signs of infection by three independent reviewers using shoulder-specific criteria. Interrater-agreement was calculated between the reviewers. If the patient had revision surgery, biopsy specimens were obtained and cultured with bacterial growth in the cultures serving as gold standard of infection. RESULTS: A total of 86 patients were included in the study. Nine patients were 18F-FDG PET/CT positive for infection, with only three true positive. Using the gold standard, infection was diagnosed after revision surgery in 22 cases. All infections were chronic and caused by low-virulent microbes. The sensitivity of 18F-FDG PET/CT was 0.14 95% CI (0.03-0.36), specificity 0.91 95% CI (0.81-0.97), positive predictive value was 0.40 95% CI (0.15-0.71) and negative predictive value 0.71 95% CI (0.67-0.75). The inter-observer agreement was 0.56 (Fleiss' kappa), indicating moderate agreement of the visual FDG-PET evaluation using the shoulder-specific criteria. CONCLUSION: 18F-FDG PET/CT has poor diagnostic accuracy in diagnosing low-grade PJI of the shoulder. 18F-FDG PET/CT cannot be recommended as a part of the routine preoperative workup to diagnose low-grade infection of a shoulder replacement.

Is hip muscle strength normalised in patients with femoroacetabular impingement syndrome one year after surgery?: Results from the HAFAI cohort.

OBJECTIVES: Little is known about hip function after hip arthroscopic surgery in patients with femoroacetabular impingement syndrome. Hence, the aim of the study was (1) to investigate changes in hip muscle strength from before to one year after hip arthroscopic surgery, (2) to compare patients with a reference group. DESIGN: Cohort study with a cross-sectional comparison. METHODS: Before and after hip arthroscopic surgery, patients underwent hip muscle strength testing of their hip flexors and extensors during concentric, isometric and eccentric contraction in an isokinetic dynamometer. Reference persons with no hip problems underwent tests at a single time point. Participants completed completed the Copenhagen Hip and Groin Outcome Score (HAGOS) questionnaire and physical capacity (stair climbing loaded and unloaded, stepping loaded and unloaded and jumping) tests. RESULTS: After surgery, hip flexion strength improved during all tests (6-13%, p<0.01) and concentric hip extension strength improved (4%, p=0.002). Hip flexion and extension strength was lower for patients than for reference persons (9-13%, p<0.05) one year after surgery. Higher hip extension strength after surgery was associated with better patient reported outcomes. Patients, who were unable to complete at minimum one test of physical capacity, demonstrated significantly weaker hip muscle strength. Compared with their healthy counterparts, female patients were more impaired than male patients. CONCLUSIONS: One year after surgery, patients improved their maximal hip muscle strength. When compared to reference persons, maximal hip muscle strength was still impaired.

Socioeconomic inequality in clinical outcome among hip fracture patients: a nationwide cohort study.

The evidence is limited regarding the association between socioeconomic status and the clinical outcome among patients with hip fracture. In this nationwide, population-based cohort study, higher education and higher family income were associated with a substantially lower 30-day mortality and risk of unplanned readmission after hip fracture. INTRODUCTION: We examined the association between socioeconomic status and 30-day mortality, acute readmission, quality of in-hospital care, time to surgery and length of hospital stay among patients with hip fracture. METHODS: This is a nationwide, population-based cohort study using prospectively collected data from the Danish Multidisciplinary Hip Fracture Registry. We identified 25,354 patients ≥65 years admitted with a hip fracture between 2010 and 2013 at Danish hospitals. Individual-level socioeconomic status included highest obtained education, family mean income, cohabiting status and migrant status. We performed multilevel regression analysis, controlling for potential confounders. RESULTS: Hip fracture patients with higher education had a lower 30-day mortality risk compared to patients with low education (7.3 vs 10.0% adjusted odds ratio (OR) = 0.74 (95% confidence interval (CI) (0.63-0.88)). The highest level of family income was also associated with lower 30-day mortality (11.9 vs 13.0% adjusted OR = 0.77, 95% CI 0.69-0.85). Cohabiting status and migrant status were not associated with 30-day mortality in the adjusted analysis. Furthermore, patients with both high education and high income had a lower risk of acute readmission (14.5 vs 16.9% adjusted OR = 0.94, 95% CI 0.91-0.97). Socioeconomic status was, however, not associated with quality of in-hospital care, time to surgery and length of hospital stay. CONCLUSIONS: Higher education and higher family income were associated with substantially lower 30-day mortality and risk of readmission after hip fracture.

Does a titanium sleeve reduce the frequency of pseudotumors in metal-on-metal total hip arthroplasty at 5-7years follow-up?

INTRODUCTION: Little is known about pseudotumor frequency and risk factors for pseudotumor formation among different types of metal-on-metal (MoM) hip arthroplasties. A lower release of chromium and cobalt have been reported in MoM hip arthroplasties with a titanium sleeve compared to MoM designs without a titanium sleeve, but yet it is unknown whether a titanium sleeve reduces the pseudotumor frequency. We conducted a cross-sectional study to investigate: 1) pseudotumor frequency, 2) risk factors of pseudotumor formation 3) and correlations between pseudotumors, serum metal-ions, implant position, and clinical symptoms. HYPOTHESIS: We expected a lower pseudotumor frequency in MoM hip articulation with a titanium sleeve than reported in MoM hip articulation designs using chromium-cobalt sleeve. MATERIALS AND METHOD: A consecutive series of 41 patients/49 hips (31 males), mean age 52 (28-68) years, participated in a 5.5±0.5 (4-6.5) year follow-up study of their M2a_Magnum hip articulation (Biomet Inc., Warsaw, Indiana, USA). Patients were evaluated with magnetic resonance imaging (MRI), measurements of serum metal-ions, plain radiographs, and clinical outcome measures of Harris Hip Score (HHS) and Oxford Hip Score (OHS). RESULTS: Eighteen of 47 hips (38%) had MRI-verified pseudotumors, all cystic, with a mean dimension of 10.6×25.6×41mm. Digital measurements on plain radiographs revealed a higher cup anteversion in patients with a pseudotumor of mean 28.4°±5.05° compared to mean 23.5°±6.5° in patients without a pseudotumor (P=0.009). Serum metal-ion concentrations, acetabular cup inclination and measures of HHS and OHS were similar between patients with and without a pseudotumor (P>0.46). CONCLUSION: At 5.5±0.5years after surgery, MRI-verified cystic pseudotumors were frequently observed in M2a_Magnum hip articulations despite the use of titanium sleeves. The pseudotumors were related to high cup anteversion angles but not related to high serum metal-ions or clinical symptoms. LEVEL OF EVIDENCE: IV: cross-sectional study.

Effect of early supervised progressive resistance training compared to unsupervised home-based exercise after fast-track total hip replacement applied to patients with preoperative functional limitations. A single-blinded randomised controlled trial.

OBJECTIVE: To examine if 2 weekly sessions of supervised progressive resistance training (PRT) in combination with 5 weekly sessions of unsupervised home-based exercise is more effective than 7 weekly sessions of unsupervised home-based exercise in improving leg-extension power of the operated leg 10 weeks after total hip replacement (THR) in patients with lower pre-operative function. METHOD: A total of 73 patients scheduled for THR were randomised (1:1) to intervention group (IG, home based exercise 5 days/week and PRT 2 days/week) or control group (CG, home based exercise 7 days/week). The primary endpoint was change in leg extension power at 10 week follow up. Secondary outcomes were isometric hip muscle strength, sit-to-stand test, stair climb test, 20 m walking speed and patient-reported outcome (HOOS). RESULTS: Sixty-two completed the trial (85%). Leg extension power increased from baseline to the 10 week follow up in both groups; mean [95% CI] IG: 0.29 [0.13; 0.45] and CG: 0.26 [0.10; 0.42] W/kg, with no between-group difference (primary outcome) (P = 0.79). Maximal walking speed (P = 0.008) and stair climb performance (P = 0.04) improved more in the IG compared to CG, no other between-group differences existed. CONCLUSIONS: In this trial, supervised PRT twice a week in addition to 5 weekly sessions of unsupervised exercise for 10 weeks was not superior to 7 weekly sessions of unsupervised home-based exercise for 10 weeks in improving the primary outcome, leg-extension power of the operated leg, at the primary endpoint 10 weeks after surgery in THR patients with lower pre-operative function. TRIAL REGISTRATION: NCT01214954.

Dexamethasone for pain after outpatient shoulder surgery: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Dexamethasone has analgesic properties when given intravenously before surgery, but the optimal dose has not been determined. We hypothesised that a dose of 40 mg dexamethasone would improve analgesia after outpatient shoulder surgery compared with 8 mg. METHODS: A randomised, double-blind, placebo-controlled clinical trial was conducted at Horsens Regional Hospital, Denmark. Patients scheduled for arthroscopic subacromial decompression and/or acromioclavicular joint resection as an outpatient procedure (n = 101) were randomised to receive intravenous dexamethasone 40 mg (D40), 8 mg (D8) or placebo (D0) before surgery. The primary outcome was pain intensity 8 h after surgery rated on a numeric rating scale of 0 to 10. Secondary outcomes were pain intensity, analgesic consumption and side effects during the first 3 days after surgery. RESULTS: Data from 73 patients were available for analysis: (D40: 25, D8: 26, D0: 22 patients). Eight hours after surgery, pain intensity were: [median (interquartile range)] group D40: 2 (1-4), group D8: 2.5 (1-5), group D0: 4 (2-7). There was no significant difference in pain intensity between group D40 and D8 after 8 h (P = 0.46) or at any other time. When comparing all three groups, a statistically significant dose-response relationship was seen for present, average and worst pain intensity after 8 h and on the following morning. No differences were found in analgesic consumption. No serious side effects were observed. CONCLUSION: Although our data supported a dose-response relationship, increasing the dexamethasone dose from 8 to 40 mg did not improve analgesia significantly after outpatient shoulder surgery.

Local infiltration analgesia for total knee arthroplasty: should ketorolac be added?

BACKGROUND: Adequate postoperative analgesia with minimal side-effects is essential for early mobilization and recovery in patients undergoing total knee arthroplasty (TKA). High-volume local infiltration analgesia (LIA) with ropivacaine has been introduced, but effects of adjuvants are still debated. We tested the hypothesis that the addition of ketorolac to LIA significantly improves analgesia after TKA. METHODS: Sixty patients undergoing TKA were randomized to receive intraoperative LIA (ropivacaine 300 mg and epinephrine 0.5 mg) combined with either ketorolac 30 mg (ketorolac group) or saline (control group). After surgery, eight bolus doses of ropivacaine 100 mg combined with either ketorolac 15 mg (ketorolac group) or saline (control group) were administered every 6 h via an intra-articular catheter. The primary outcome was postoperative consumption of i.v. morphine patient-controlled analgesia (PCA). Secondary outcomes were time to first request of i.v. morphine PCA, pain intensity, side-effects, and readiness for hospital discharge. RESULTS: Consumption of i.v. morphine PCA was lower in the ketorolac group vs control group {0-6 h: 0 (0-0) vs 5 (0-10) mg, P<0.0001; 0-48 h: 10 (0-22.5) vs 48.75 (30-82.5) mg, P<0.0001 [median (inter-quartile range, IQR)]}. Time to first request of i.v. morphine PCA was longer in the ketorolac group vs the control group [490 (248-617) vs 223 (115-319) min, P=0.02, median (IQR)]. Early postoperative pain (<48 h) and readiness for hospital discharge were also significantly reduced in the ketorolac group. CONCLUSIONS: LIA with ketorolac results in reduced morphine consumption, reduced pain intensity, and earlier readiness for hospital discharge.

Delirium after fast-track hip and knee arthroplasty.

BACKGROUND: Postoperative delirium (PD) is a serious complication after major surgery in elderly patients. PD is well defined and characterized by reduced attention and disorientation. Multimodal optimization of perioperative care (the fast-track methodology) enhances recovery, and reduces hospital stay and medical morbidity. No data on PD are available in fast-track surgery. The aim of this study was to evaluate the incidence of PD after fast-track hip (THA) and knee arthroplasty (TKA) with anticipated length of stay (LOS) of <3 days. METHODS: In a prospective multicentre study to evaluate postoperative cognitive dysfunction, we included 225 non-demented patients with a mean age of 70 yr undergoing either THA or TKA in a fast-track set-up. Anaesthesia and postoperative pain management were standardized with limited opioid use. Nursing staff were trained to look for symptoms of PD which was assessed during interaction with healthcare professionals. Patients were invited for a clinical follow-up 1-2 weeks after surgery. RESULTS: Clinical follow-up was performed in 220 patients at a mean of 12.0 days after surgery while five patients were followed up by telephone. The mean LOS was 2.6 days (range 1-8 days). Twenty-two patients received general anaesthesia, and the rest had spinal anaesthesia. No patients developed PD (95% confidence interval 0.0-1.6%). CONCLUSIONS: A fast-track set-up with multimodal opioid-sparing analgesia was associated with lack of PD after elective THA and TKA in elderly patients.

The combined effect of parathyroid hormone and bone graft on implant fixation.

Impaction allograft is an established method of securing initial stability of an implant in arthroplasty. Subsequent bone integration can be prolonged, and the volume of allograft may not be maintained. Intermittent administration of parathyroid hormone has an anabolic effect on bone and may therefore improve integration of an implant. Using a canine implant model we tested the hypothesis that administration of parathyroid hormone may improve osseointegration of implants surrounded by bone graft. In 20 dogs a cylindrical porous-coated titanium alloy implant was inserted into normal cancellous bone in the proximal humerus and surrounded by a circumferential gap of 2.5 mm. Morsellised allograft was impacted around the implant. Half of the animals were given daily injections of human parathyroid hormone (1-34) 5 µg/kg for four weeks and half received control injections. The two groups were compared by mechanical testing and histomorphometry. We observed a significant increase in new bone formation within the bone graft in the parathyroid hormone group. There were no significant differences in the volume of allograft, bone-implant contact or in the mechanical parameters. These findings suggest that parathyroid hormone improves new bone formation in impacted morsellised allograft around an implant and retains the graft volume without significant resorption. Fixation of the implant was neither improved nor compromised at the final follow-up of four weeks.

Serial dilation reduces graft slippage compared to extraction drilling in anterior cruciate ligament reconstruction: a randomized controlled trial using radiostereometric analysis.

PURPOSE: This study tested the hypothesis that serial dilation of the tibial tunnel could provide a stronger anchorage of the graft-fixation-device complex compared to traditional extraction drilling. METHODS: Forty patients (22 men and 18 women) undergoing ACL reconstruction were randomized to either extraction drilling (group ED) or compaction by serial dilation (group SD) of the tibial tunnel. Tantalum beads were placed in the tibia, femur, and in the hamstring graft. Radiostereometric analysis (RSA) was performed postoperatively and again after 6, 12, and 24 weeks. Migration of graft in the bone tunnels as well as knee laxity was assessed using RSA and a TELOS stress device. RESULTS: Six patients (three men and three women) were excluded during follow-up, which resulted in 17 patients in group ED [median age 30 years (range 20-50)] and 17 patients in group SD [median age 32 years (range 20-49)]. The mean migration of the graft in the tibial bone canal after 3 months was 1.3 (SD 0.6) mm in group ED and 0.8 (SD 0.5) mm in group SD (P = 0.02). The overall knee laxity after 3 months was 13.0 (SD 4.0) mm in group ED and 10.9 (SD 3.1) mm in group SD. CONCLUSION: This study found less slippage of the hamstring graft in the tibial bone canal in the serial dilated group compared to the extraction drilling group. The clinical relevance of the difference is unknown. No difference in stress radiographic knee laxity was found between the two groups.

The combination of radiostereometric analysis and the telos stress device results in poor precision for knee laxity measurements after anterior cruciate ligament reconstruction.

PURPOSE: Several devices for measuring knee laxity following anterior cruciate ligament ACL reconstruction exist, but the precision of the methods has never been optimal. Therefore, a new standardized protocol (NSP) was made, aiming at ensuring a reliable positioning of the Telos Stress Device (TSD) which theoretically could result in precise knee laxity measurements when using radiostereometric analysis (RSA) in combination with TSD. METHOD: The TSD was applied to the knee of 30 healthy persons, using both the NSP and the official company instructions. The position of the stress arms of the TSD was marked following each measurement. The reliability of each protocol was calculated as the difference in length between the first and second markings. The NSP for the TSD was then used in a clinical study. Thirty-five patients underwent ACL reconstruction. Double measurements of knee laxity by RSA were performed at a 3-month follow-up. RESULTS: Using the NSP for TSD positioning, the prediction interval at the marking sites ranged from ±0.4 to ±1.1 mm. Following the company instructions, the prediction interval ranged from ±0.8 to ±3.9 mm depending on marking site. Thus, the precision of positioning the stress arms of the TSD was improved at all marking sites using the NSP compared with the original company protocol. The double measurements of the knee laxity in the clinical study resulted in a mean difference of 0.0 mm and a prediction interval of ±5.2 mm. CONCLUSION: Even though the NSP improved the positioning of the TSD on patients' extremities, the combination of NSP-TSD and RSA was not able to provide acceptable knee laxity measurements in a clinical setting compared with published precision data for other devices on the market. Therefore, the Telos Stress Device is not recommendable for use in knee laxity measurements following ACL reconstruction.

Serial dilation versus extraction drilling in anterior cruciate ligament reconstruction: a biomechanical study.

The hamstring tendon graft has become increasingly popular in anterior cruciate ligament reconstruction because of low donor-site morbidity. However, the tibial fixation is considered difficult, mainly because of low tibial mineral bone density. Therefore, we tested whether preparation of the tibial tunnel with compaction by serial dilation provided a stronger anchorage of the graft-fixation-device complex than does traditional extraction drilling of the tibial tunnel. In 20 bovine tibiae, the bone tunnels were created with either extraction drilling (group 1) or compaction by serial dilation (group 2). Twenty bovine digital extensor tendons were fixated in the bone tunnel with an Intrafix tibial fastener. The graft-fixation-device complexes were mounted in a hydraulic test machine. The fixation strength was evaluated after cyclic loading. The difference between the serial dilation group and the extraction drilling group ranged from a mean slippage of 0 mm at 70-220 N, to a mean slippage of 0.1 mm at 70-520 N. We found no significant difference in slippage of the graft-fixation-device complex after 1,600 cycles. This study failed to show a significant difference between compaction by serial dilation and extraction drilling of the tibia bone tunnel in anterior cruciate ligament reconstruction.

A new minimally invasive transsartorial approach for periacetabular osteotomy.

BACKGROUND: A new minimally invasive transsartorial approach for the Bernese periacetabular osteotomy was developed. We investigated whether this technique was safe and successful with regard to minimizing tissue trauma and, more importantly, whether it was possible to obtain optimal reorientation of the acetabulum. METHODS: Our experience with this approach was retrospectively assessed by means of database inquiry and the evaluation of radiographs. We assessed ninety-four procedures performed between April 2003 and August 2005 to determine perioperative and early postoperative outcome measures, the achieved acetabular reorientation, and hip joint survival. RESULTS: The mean duration of surgery was 73.1 minutes, the median perioperative blood loss was 250 mL, and the mean reduction in the hemoglobin level was 33 g/L. Blood transfusion was required following 3% of the procedures. No injuries to the great vessels or nerves, arterial thromboses, unintended extension of the osteotomy, or deep infections occurred. The postoperative acetabular reorientation was assessed by measuring the center-edge and acetabular index angles, the medians of which were 34 degrees and 3 degrees , respectively. With total hip arthroplasty as the end point, the hip joint survival rate was estimated to be 98% at 4.3 years. CONCLUSIONS: Osteotomy with use of this minimally invasive transsartorial approach appears to be a safe, relatively short surgical procedure associated with a relatively small amount of blood loss and minimal transfusion requirements. Optimal acetabular reorientation can be achieved with this technique.

Ultrasound versus magnetic resonance arthrography in acetabular labral tear diagnostics: a prospective comparison in 20 dysplastic hips.

BACKGROUND: Acetabular labral tears are highly associated with hip dysplasia. Magnetic resonance arthrography (MR arthrography) is the expensive and time-consuming contemporary gold-standard method in the radiological assessment of acetabular labral tears. PURPOSE: To assess the diagnostic ability of noninvasive ultrasound (US) examination compared to MR arthrography in diagnosing acetabular labral tears in dysplastic hip joints. MATERIAL AND METHODS: The study compared US examination and MR arthrography diagnosis of labral tears in 20 consecutively referred dysplastic hip joints. RESULTS: The ability to diagnose acetabular labral tears upon US examination was calculated: sensitivity 44%, specificity 75%, positive predictive value 88%, and negative predictive value 25%. CONCLUSION: The ability of US examination in diagnosing acetabular labral tears is not yet good enough. The technique is still to be developed, and more experience, especially with the interpretation of US examinations, is needed.

Effects of as-cast and wrought Cobalt-Chrome-Molybdenum and Titanium-Aluminium-Vanadium alloys on cytokine gene expression and protein secretion in J774A.1 macrophages.

Insertion of metal implants is associated with a possible change in the delicate balance between pro- and anti-inflammatory proteins, probably leading to an unfavourable predominantly pro-inflammatory milieu. The most likely cause is an inappropriate activation of macrophages in close relation to the metal implant and wear-products. The aim of the present study was to compare surfaces of as-cast and wrought Cobalt-Chrome-Molybdenum (CoCrMo) alloys and Titanium-Aluminium-Vanadium (TiAlV) alloy when incubated with mouse macrophage J774A.1 cell cultures. Changes in pro- and anti-inflammatory cytokines (TNF-alpha, IL-6, IL-alpha, IL-1beta, IL-10) and proteins known to induce proliferation (M-CSF), chemotaxis (MCP-1) and osteogenesis (TGF-beta, OPG) were determined by ELISA and Real Time reverse transcriptase - PCR (Real Time rt-PCR). Lactate dehydrogenase (LDH) was measured in the medium to asses the cell viability. Surface properties of the discs were characterised with a profilometer and with energy dispersive X-ray spectroscopy. We here report, for the first time, that the prosthetic material surface (non-phagocytable) of as-cast high carbon CoCrMo reduces the pro-inflammatory cytokine IL-6 transcription, the chemokine MCP-1 secretion, and M-CSF secretion by 77%, 36%, and 62%, respectively. Furthermore, we found that reducing surface roughness did not affect this reduction. The results suggest that as-cast CoCrMo alloy is more inert than wrought CoCrMo and wrought TiAlV alloys and could prove to be a superior implant material generating less inflammation which might result in less osteolysis.

Osteogenic protein-1 increases the fixation of implants grafted with morcellised bone allograft and ProOsteon bone substitute: an experimental study in dogs.

Impacted bone allograft is often used in revision joint replacement. Hydroxyapatite granules have been suggested as a substitute or to enhance morcellised bone allograft. We hypothesised that adding osteogenic protein-1 to a composite of bone allograft and non-resorbable hydroxyapatite granules (ProOsteon) would improve the incorporation of bone and implant fixation. We also compared the response to using ProOsteon alone against bone allograft used in isolation. We implanted two non-weight-bearing hydroxyapatite-coated implants into each proximal humerus of six dogs, with each implant surrounded by a concentric 3 mm gap. These gaps were randomly allocated to four different procedures in each dog: 1) bone allograft used on its own; 2) ProOsteon used on its own; 3) allograft and ProOsteon used together; or 4) allograft and ProOsteon with the addition of osteogenic protein-1. After three weeks osteogenic protein-1 increased bone formation and the energy absorption of implants grafted with allograft and ProOsteon. A composite of allograft, ProOsteon and osteogenic protein-1 was comparable, but not superior to, allograft used on its own. ProOsteon alone cannot be recommended as a substitute for allograft around non-cemented implants, but should be used to extend the volume of the graft, preferably with the addition of a growth factor.