Elbow kinematics with increased lengthening of a radial head arthroplasty evaluated with dynamic radiostereometric analysis.

Aims: The aim of this study was to evaluate the kinematics of the elbow following increasing length of the radius with implantation of radial head arthroplasties (RHAs) using dynamic radiostereometry (dRSA). Methods: Eight human donor arms were examined by dRSA during motor-controlled flexion and extension of the elbow with the forearm in an unloaded neutral position, and in pronation and supination with and without a 10 N valgus or varus load, respectively. The elbows were examined before and after RHA with stem lengths of anatomical size, + 2 mm, and + 4 mm. The ligaments were maintained intact by using a step-cut lateral humeral epicondylar osteotomy, allowing the RHAs to be repeatedly exchanged. Bone models were obtained from CT scans, and specialized software was used to match these models with the dRSA recordings. The flexion kinematics of the elbow were described using anatomical coordinate systems to define translations and rotations with six degrees of freedom. Results: The greatest kinematic changes in the elbows were seen with the longest, + 4 mm, implant, which imposed a mean joint distraction of 2.8 mm in the radiohumeral joint and of 1.1 mm in the ulnohumeral joint, an increased mean varus angle of up to 2.4° for both the radius and the ulna, a mean shift of the radius of 2.0 mm in the ulnar direction, and a mean shift of the ulna of 1.0 mm posteriorly. Conclusion: The kinematics of the elbow deviated increasingly from those of the native joint with a 2 mm to a 4 mm lengthening of the radius. This confirms the importance of restoring the natural length of the radius when undertaking RHA.

Glenohumeral joint kinematics during apprehension-relocation test in patients with anterior shoulder instability and glenoid bone loss.

Aims: This study aimed to quantify the shoulder kinematics during an apprehension-relocation test in patients with anterior shoulder instability (ASI) and glenoid bone loss using the radiostereometric analysis (RSA) method. Kinematics were compared with the patient's contralateral healthy shoulder. Methods: A total of 20 patients with ASI and > 10% glenoid bone loss and a healthy contralateral shoulder were included. RSA imaging of the patient's shoulders was performed during a repeated apprehension-relocation test. Bone volume models were generated from CT scans, marked with anatomical coordinate systems, and aligned with the digitally reconstructed bone projections on the RSA images. The glenohumeral joint (GHJ) kinematics were evaluated in the anteroposterior and superoinferior direction of: the humeral head centre location relative to the glenoid centre; and the humeral head contact point location on the glenoid. Results: During the apprehension test, the centre of the humeral head was 1.0 mm (95% CI 0.0 to 2.0) more inferior on the glenoid for the ASI shoulder compared with the healthy shoulder. Furthermore, the contact point of the ASI shoulder was 1.4 mm (95% CI 0.3 to 2.5) more anterior and 2.0 mm (95% CI 0.8 to 3.1) more inferior on the glenoid compared with the healthy shoulder. The contact point of the ASI shoulder was 1.2 mm (95% CI 0.2 to 2.6) more anterior during the apprehension test compared to the relocation test. Conclusion: The humeral head centre was located more inferior, and the GHJ contact point was located both more anterior and inferior during the apprehension test for the ASI shoulders than the healthy shoulders. Furthermore, the contact point displacement between the apprehension and relocation test revealed increased joint laxity for the ASI shoulder than the healthy shoulders. These results contribute to existing knowledge that ASI shoulders with glenoid bone loss may also suffer from inferior shoulder instability.

Radial head arthroplasty diameter impact on elbow kinematics evaluated by dynamic radiostereometric analysis.

Purpose: Radial head arthroplasty (RHA) reestablishes elbow stability after complex radial head fracture, but complication rates are high, possibly due to inappropriate implant sizing. Knowledge of impact of radial head implant diameter on elbow kinematics is limited and warranted. This study evaluated elbow kinematics of different radial head implant diameters after RHA using dynamic radiostereometric analysis (dRSA). Methods: Eight human donor arms were examined with dRSA during elbow flexion with the forearm in unloaded neutral position, and in supinated- and pronated position without and with 10N either varus or valgus load, respectively. Elbow kinematics were examined before and after RHA with head diameters of anatomical size, -2 mm (undersized), and +2 mm (oversized). The ligaments were kept intact by use of step-cut humerus osteotomy for repeated RHA exchange. Bone models were obtained from CT, and by AutoRSA software bone models were matched with dRSA recordings. The elbow kinematics were described using anatomical coordinate systems. Results: Compared to the native radial head during elbow flexion, the anatomical sized RHA shifted 2.0 mm in ulnar direction during unloaded pronated forearm position. The undersized RHA shifted 1.5 mm in posterior direction and 2.1 mm in ulnar direction during unloaded pronated forearm position and increased the varus angle by 2.4° during supinated loaded forearm position. The oversized RHA shifted 1.6 mm in radial direction during loaded supinated forearm position. Conclusions: The anatomically sized RHA should be preferred as it maintained native elbow kinematics the best. The kinematic changes with oversized and undersized RHA diameters were small, suggesting forgiveness for the RHA diameter size. Level of Evidence: Level III.

Transformer-based structuring of free-text radiology report databases.

OBJECTIVES: To provide insights for on-site development of transformer-based structuring of free-text report databases by investigating different labeling and pre-training strategies. METHODS: A total of 93,368 German chest X-ray reports from 20,912 intensive care unit (ICU) patients were included. Two labeling strategies were investigated to tag six findings of the attending radiologist. First, a system based on human-defined rules was applied for annotation of all reports (termed "silver labels"). Second, 18,000 reports were manually annotated in 197 h (termed "gold labels") of which 10% were used for testing. An on-site pre-trained model (Tmlm) using masked-language modeling (MLM) was compared to a public, medically pre-trained model (Tmed). Both models were fine-tuned on silver labels only, gold labels only, and first with silver and then gold labels (hybrid training) for text classification, using varying numbers (N: 500, 1000, 2000, 3500, 7000, 14,580) of gold labels. Macro-averaged F1-scores (MAF1) in percent were calculated with 95% confidence intervals (CI). RESULTS: Tmlm,gold (95.5 [94.5-96.3]) showed significantly higher MAF1 than Tmed,silver (75.0 [73.4-76.5]) and Tmlm,silver (75.2 [73.6-76.7]), but not significantly higher MAF1 than Tmed,gold (94.7 [93.6-95.6]), Tmed,hybrid (94.9 [93.9-95.8]), and Tmlm,hybrid (95.2 [94.3-96.0]). When using 7000 or less gold-labeled reports, Tmlm,gold (N: 7000, 94.7 [93.5-95.7]) showed significantly higher MAF1 than Tmed,gold (N: 7000, 91.5 [90.0-92.8]). With at least 2000 gold-labeled reports, utilizing silver labels did not lead to significant improvement of Tmlm,hybrid (N: 2000, 91.8 [90.4-93.2]) over Tmlm,gold (N: 2000, 91.4 [89.9-92.8]). CONCLUSIONS: Custom pre-training of transformers and fine-tuning on manual annotations promises to be an efficient strategy to unlock report databases for data-driven medicine. KEY POINTS: • On-site development of natural language processing methods that retrospectively unlock free-text databases of radiology clinics for data-driven medicine is of great interest. • For clinics seeking to develop methods on-site for retrospective structuring of a report database of a certain department, it remains unclear which of previously proposed strategies for labeling reports and pre-training models is the most appropriate in context of, e.g., available annotator time. • Using a custom pre-trained transformer model, along with a little annotation effort, promises to be an efficient way to retrospectively structure radiological databases, even if not millions of reports are available for pre-training.

Interventions for treating proximal humeral fractures in adults.

BACKGROUND: Fractures of the proximal humerus, often termed shoulder fractures, are common injuries, especially in older people. The management of these fractures varies widely, including in the use of surgery. This is an update of a Cochrane Review first published in 2001 and last updated in 2015. OBJECTIVES: To assess the effects (benefits and harms) of treatment and rehabilitation interventions for proximal humeral fractures in adults. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, trial registries, and bibliographies of trial reports and systematic reviews to September 2020. We updated this search in November 2021, but have not yet incorporated these results. SELECTION CRITERIA: We included randomised and quasi-randomised controlled trials that compared non-pharmacological interventions for treating acute proximal humeral fractures in adults.  DATA COLLECTION AND ANALYSIS: Pairs of review authors independently selected studies, assessed risk of bias and extracted data. We pooled data where appropriate and used GRADE for assessing the certainty of evidence for each outcome. We prepared a brief economic commentary for one comparison. MAIN RESULTS: We included 47 trials (3179 participants, mostly women and mainly aged 60 years or over) that tested one of 26 comparisons. Six comparisons were tested by 2 to 10 trials, the others by small single-centre trials only. Twelve studies evaluated non-surgical treatments, 10 compared surgical with non-surgical treatments, 23 compared two methods of surgery, and two tested timing of mobilisation after surgery. Most trials were at high risk of bias, due mainly to lack of blinding. We summarise the findings for four key comparisons below. Early (usually one week post injury) versus delayed (after three or more weeks) mobilisation for non-surgically-treated fractures Five trials (350 participants) made this comparison; however, the available data are very limited. Due to very low-certainty evidence from single trials, we are uncertain of the findings of better shoulder function at one year in the early mobilisation group, or the findings of little or no between-group difference in function at 3 or 24 months. Likewise, there is very low-certainty evidence of no important between-group difference in quality of life at one year. There was one reported death and five serious shoulder complications (1.9% of 259 participants), spread between the two groups, that would have required substantive treatment. Surgical versus non-surgical treatment Ten trials (717 participants) evaluated surgical intervention for displaced fractures (66% were three- or four-part fractures). There is high-certainty evidence of no clinically important difference between surgical and non-surgical treatment in patient-reported shoulder function at one year (standardised mean difference (SMD) 0.10, 95% confidence interval (CI) -0.07 to 0.27; 7 studies, 552 participants) and two years (SMD 0.06, 95% CI -0.13 to 0.25; 5 studies, 423 participants). There is moderate-certainty evidence of no clinically important between-group difference in patient-reported shoulder function at six months (SMD 0.17, 95% CI -0.04 to 0.38; 3 studies, 347 participants). There is high-certainty evidence of no clinically important between-group difference in quality of life at one year (EQ-5D (0: dead to 1: best quality): mean difference (MD) 0.01, 95% CI -0.02 to 0.04; 6 studies, 502 participants). There is low-certainty evidence of little between-group difference in mortality: one of the 31 deaths was explicitly linked with surgery (risk ratio (RR) 1.35, 95% CI 0.70 to 2.62; 8 studies, 646 participants). There is low-certainty evidence of a higher risk of additional surgery in the surgery group (RR 2.06, 95% CI 1.21 to 3.51; 9 studies, 667 participants). Based on an illustrative risk of 35 subsequent operations per 1000 non-surgically-treated patients, this indicates an extra 38 subsequent operations per 1000 surgically-treated patients (95% CI 8 to 94 more). Although there was low-certainty evidence of a higher overall risk of adverse events after surgery, the 95% CI also includes a slightly increased risk of adverse events after non-surgical treatment (RR 1.46, 95% CI 0.92 to 2.31; 3 studies, 391 participants). Open reduction and internal fixation with a locking plate versus a locking intramedullary nail Four trials (270 participants) evaluated surgical intervention for displaced fractures (63% were two-part fractures). There is low-certainty evidence of no clinically important between-group difference in shoulder function at one year (SMD 0.15, 95% CI -0.12 to 0.41; 4 studies, 227 participants), six months (Disability of the Arm, Shoulder, and Hand questionnaire (0 to 100: worst disability): MD -0.39, 95% CI -4.14 to 3.36; 3 studies, 174 participants), or two years (American Shoulder and Elbow Surgeons score (ASES) (0 to 100: best outcome): MD 3.06, 95% CI -0.05 to 6.17; 2 studies, 101 participants). There is very low-certainty evidence of no between-group difference in quality of life (1 study), and of little difference in adverse events (4 studies, 250 participants) and additional surgery (3 studies, 193 participants). Reverse total shoulder arthroplasty (RTSA) versus hemiarthroplasty There is very low-certainty evidence from two trials (161 participants with either three- or four-part fractures) of no or minimal between-group differences in self-reported shoulder function at one year (1 study) or at two to three years' follow-up (2 studies); or in quality of life at one year or at two or more years' follow-up (1 study). Function at six months was not reported. Of 10 deaths reported by one trial (99 participants), one appeared to be surgery-related. There is very low-certainty evidence of a lower risk of complications after RTSA (2 studies). Ten people (6.2% of 161 participants) had a reoperation; all eight cases in the hemiarthroplasty group received a RTSA (very low-certainty evidence). AUTHORS' CONCLUSIONS: There is high- or moderate-certainty evidence that, compared with non-surgical treatment, surgery does not result in a better outcome at one and two years after injury for people with displaced proximal humeral fractures. It may increase the need for subsequent surgery. The evidence is absent or insufficient for people aged under 60 years, high-energy trauma, two-part tuberosity fractures or less common fractures, such as fracture dislocations and articular surface fractures. There is insufficient evidence from randomised trials to inform the choices between different non-surgical, surgical or rehabilitation interventions for these fractures.

Neurofilament Light Chain Is a Biomarker of Neurodegeneration in Ataxia Telangiectasia.

Ataxia telangiectasia (A-T) is a progressive and life-limiting disease associated with cerebellar ataxia due to progressive cerebellar degeneration. In addition to ataxia, which is described in detail, the presence of chorea, dystonia, oculomotor apraxia, athetosis, parkinsonism, and myoclonia are typical manifestations of the disease. The study aimed to evaluate the specificity and sensitivity of neurofilament light chain (NfL) as a biomarker of neurodegeneration in relation to SARA score. In this prospective trial, one visit of 42 A-T patients aged 1.3-25.6 years (mean 11.6 ± 7.3 years) was performed, in which NfL was determined from serum by ELISA. Additionally, a neurological examination of the patients was performed. Blood was collected from 19 healthy volunteers ≥ 12 years of age. We found significantly increased levels of NfL in patients with A-T compared to healthy controls (21.5 ± 3.6 pg/mL vs. 9.3 ± 0.49 pg/mL, p ≤ 0.01). There was a significant correlation of NfL with age, AFP, and SARA. NfL is a new potential progression biomarker in blood for neurodegeneration in A-T which increases with age.

Altered Cerebrospinal Fluid (CSF) in Children with Ataxia Telangiectasia.

Ataxia telangiectasia (A-T) is a devastating multi-system disorder characterized by progressive cerebellar ataxia and immunodeficiency. The neurological decline may be caused by multiple factors of which ongoing inflammation and oxidative stress may play a dominant role. The objective of the present investigation was to determine cerebrospinal fluid (CSF) proteins and possible low-grade inflammation and its relation to age and neurological deterioration. In the present study, we investigated 15 patients with A-T from 2 to 16 years. Our investigation included blood and CSF tests, clinical neurological examination, A-T score, and MRI findings. The albumin ratio (AR) was analyzed to determine the blood-brain-barrier function. In addition, inflammatory cytokines (IL-1α, IL-6, IL-8, IL-12 p40, IL-17A, IFN-γ, TNF-α) were measured by the multiplex cytometric bead array. We compared the results with those from an age-matched control group. Three of the A-T patients were analyzed separately (one after resection of a cerebral meningioma, one after radiation and chemotherapy due to leukemia, one after stem cell transplantation). Patient had significantly more moderate and severe side effects due to CSF puncture (vomiting, headache, need for anti-emetic drugs) compared with healthy controls. Total protein, albumin, and the AR increased with age indicating a disturbed blood barrier function in older children. There were no differences for cytokines in serum and CSF with the exception of IL-2, which was significantly higher in controls in serum. The AR is significantly altered in A-T patients, but low-grade inflammation is not detectable in serum and CSF.

Splinting versus extension-block pinning of bony mallet finger: a randomized clinical trial.

Surgical treatment of bony mallet fingers is frequently recommended, but the evidence is sparse. This randomized clinical trial aimed to compare nonoperative splinting versus extension-block pinning of bony mallet fingers with involvement of more than one-third of the joint surface but without primary joint subluxation. Thirty-two patients were randomized and 28 fulfilled the protocol. At 6 months follow-up, there were no significant differences in active extension lag in the distal interphalangeal joint (the primary outcome) or in patient-reported function and pain scores. Flexion and active range of motion in the distal interphalangeal joint and finger-to-palm distance were better in the splinting group, but three patients developed secondary subluxation. We conclude from this study, that splinting these injuries is safe and efficient in restoring joint motion, but splinting does not sufficiently prevent secondary subluxation of the joint. Radiographic follow-up during splinting appears to be necessary. Level of evidence: I.

Microdialysis for the Assessment of Intervertebral Disc and Vertebral Cancellous Bone Metabolism in a Large Porcine Model.

BACKGROUND/AIM: It remains challenging to evaluate the in vivo pathophysiological biochemical characteristics in spine tissue, due to lack of an applicable model and feasible methods. The aim of this study was to apply microdialysis for the assessment of basic metabolites from the C3-C4 intervertebral disc, C3 vertebral cancellous bone and subcutaneous adipose tissue in a large porcine model. MATERIALS AND METHODS: In 7 pigs, glucose, pyruvate, lactate and glycerol concentrations were evaluated in an 8-hour sampling period. RESULTS: The mean lactate/pyruvate (L/P) ratios for the intervertebral disc and vertebral cancellous bone were comparable and exceeded the ischemic cut-off value of 25 for the entire sampling interval. For subcutaneous adipose tissue, the L/P ratio was below the ischemic cut-off. CONCLUSION: This exploratory study confirms previous findings of ischemia in bone and the intervertebral disc. This encourages new microdialysis study designs in spine tissue employing large porcine models to create new knowledge and a greater understanding of the metabolism and pathogenesis in spine tissue.

The Danish version of the Western Ontario Rotator Cuff Index.

INTRODUCTION: The aim of this study was to cross-culturally adapt the Western Ontario Rotator Cuff Index (WORC) into a Danish version (D-WORC) and evaluate its validity, reliability and responsiveness in patients undergoing surgery for arthroscopic subacromial decompression or rotator cuff repair. METHODS: The original WORC version was cross-culturally adapted into Danish and, the validity, test-retest reliability, responsiveness construct validity, internal consistency, interclass correlation coefficient (ICC), limits of agreement (LOA) and an anchor minimal important change (MIC) were assessed using the Disabilities of Arm, Shoulder and Hand (DASH), the Oxford Shoulder Score (OSS), the Short Form-36 and the global rating scale. RESULTS: The cross-cultural adaption was successful. The correlation was high between the D-WORC and DASH (Pearson's correlation coefficient (PCC) = 0.71; 95% confidence interval (CI): 0.60-0.79) and moderate between the D-WORC and the OSS (PCC = 0.67; 95% CI: 0.55-0.76). Reliability analysis showed an ICC of 0.80 (95% CI: 0.69-0.87) and an internal consistency of 0.94 (95% CI: 0.92-0.95). The test-retest mean difference was 76.4 (± standard deviation = 201.40). LOA ranged from -318.3 (95% CI: -387.8--248.9) to 471.2 (95% CI: 401.7-540.6) for the total WORC score. The MIC was -211 in the total score. CONCLUSIONS: The D-WORC is a valid, reliable and responsive questionnaire that can be used in Danish populations. FUNDING: Lone Dragnes Brix: Familien Hede Nielsens Fond, Gurli og Hans Engell Friis' Fond, Aase og Ejnar Danielsens Fond, Knud og Edith Eriksons Mindefond, Region Midtjyllands Sundhedsvidenskabelige Forskningsfond. TRIAL REGISTRATION: Danish Data Protection Agency: 1-16-02-653-15.

Elbow Biomechanics, Radiocapitellar Joint Pressure, and Interosseous Membrane Strain Before and After Radial Head Arthroplasty.

Complex radial head fracture and elbow instability can be treated with radial head arthroplasty. Good clinical results have been described after this surgical treatment. However, the revision and complication rate reported in the literature is concerning. This might be due to altered kinematics after radial head arthroplasty. Eight human native elbows were examined with dynamic radiostereometric analysis and compared with a radial head arthroplasty. Translations of the radial head in the x-, y-, and z-directions relative to the humerus and the ulna were measured. The radiocapitellar joint pressure was measured using a pressure sensor. The tension within the interosseous membrane was measured using a custom-made strain gauge. After radial head arthroplasty, the radial head was displaced approximately 1.8 mm medially and 1.4 mm distally at the starting point. During unloaded flexion motion the difference in all translations between the native radial head and the radial head arthroplasty was less than 1 mm (95% confidence interval [CI] ± 0.5 mm) (p = 0.001). With loading the difference was less than 1.5 mm (95% CI ± 1.5 mm) (p = 0.001). The mean difference in radiocapitellar joint contact pressure was less than 0.30 MPa (95% CI ± 0.40 MPa) (p = 0.001) during unloaded flexion motion. There were only submillimetre kinematic changes and small changes in joint pressure and interosseous membrane tension after the insertion of a radial head arthroplasty in an experimental setting. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:510-522, 2020.

The Effect of Text Messaging on Medication Adherence After Outpatient Knee Arthroscopy: A Randomized Controlled Trial.

PURPOSE: The purpose of this project was to examine if text message reminders can increase postoperative adherence to treatment with acetaminophen among outpatients undergoing arthroscopic knee surgery. DESIGN: A nonblinded randomized control trial. METHODS: In this study, 187 patients were randomized to either an intervention group (text message reminders) or a control group (no text message reminders). On the fourth postoperative day, all patients received an electronic questionnaire concerning (1) adherence to treatment with acetaminophen (main outcome), (2) pain intensity, and (3) unscheduled health care contacts. FINDINGS: Data were available from 134 patients (intervention group, n = 70; control group, n = 64). No significant differences between groups were found regarding the median number of missed acetaminophen doses (1 vs 2.5; P = .06), pain intensity at rest and during walking, or the number of unscheduled health care contacts (7 vs 4; P = .35). CONCLUSIONS: A nonsignificant trend toward an increased medication adherence of acetaminophen was found.

Vancomycin concentrations in the cervical spine after intravenous administration: results from an experimental pig study.

Background and purpose - Vancomycin may be an important drug for intravenous perioperative antimicrobial prophylaxis in spine surgery. We assessed single-dose vancomycin intervertebral disc, vertebral cancellous bone, and subcutaneous adipose tissue concentrations using microdialysis in a pig model. Material and methods - 8 female pigs received 1,000 mg of vancomycin intravenously as a single dose over 100 minutes. Microdialysis probes were placed in the C3-C4 intervertebral disc, C3 vertebral cancellous bone, and subcutaneous adipose tissue, and vancomycin concentrations were obtained over 8 hours. Venous blood samples were obtained as reference. Results - Ranging from 0.24 to 0.60, vancomycin tissue penetration, expressed as the ratio of tissue to plasma area under the concentration-time curve from 0 to the last measured value, was incomplete for all compartments. The lowest penetration was found in the intervertebral disc. The time to a mean clinically relevant minimal inhibitory concentration (MIC) of 4 µg/mL was 3, 17, 25, and 156 min for plasma, subcutaneous adipose tissue, vertebral cancellous bone, and the intervertebral disc, respectively. In contrast to the other compartments, a mean MIC of 8 µg/mL was not reached in the intervertebral disc. An approximately 3-times longer elimination rate was observed in the intervertebral disc in comparison with all the other compartments (p < 0.001), and the time to peak drug concentration was higher for all tissues compared with plasma Interpretation - Preoperative administration of 1,000 mg of vancomycin may provide adequate vancomycin tissue concentrations with a considerable delay, though tissue penetration was incomplete. However, in order also to achieve adequate intervertebral disc concentrations in all individuals and accommodating a potentially higher MIC target, supplemental application of vancomycin may be necessary.

Bone and subcutaneous adipose tissue pharmacokinetics of vancomycin in total knee replacement patients.

Background and purpose - The incidence of orthopedic methicillin-resistant Staphylococcus aureus (MRSA) infections is increasing. Vancomycin may therefore play an increasingly important role in orthopedic perioperative antimicrobial prophylaxis. Studies investigating perioperative bone and soft tissue concentrations of vancomycin are sparse and challenged by a lack of appropriate methods. We assessed single-dose plasma, subcutaneous adipose tissue (SCT) and bone concentrations of vancomycin using microdialysis in male patients undergoing total knee replacement. Methods - 1,000 mg of vancomycin was administered postoperatively intravenously over 100 minutes to 10 male patients undergoing primary total knee replacement. Vancomycin concentrations in plasma, SCT, cancellous, and cortical bone were measured over the following 8 hours. Microdialysis was applied for sampling in solid tissues. Results - For all solid tissues, tissue penetration of vancomycin was significantly impaired. The time to a mean clinically relevant minimal inhibitory concentration (MIC) of 2 mg/L was 3, 36, 27, and 110 min for plasma, SCT, cancellous, and cortical bone, respectively. As opposed to the other compartments, a mean MIC of 4 mg/L could not be reached in cortical bone. The area under the concentration-time curve from 0 to the last measured value and peak drug concentrations (Cmax) for SCT, cancellous, and cortical bone was lower than that of free plasma. The time to Cmax was higher for all tissues compared with free plasma. Interpretation - Postoperative penetration of vancomycin to bone and SCT was impaired and delayed in male patients undergoing total knee replacement surgery. Adequate perioperative vancomycin concentrations may not be reached using standard prophylactic dosage.

Outcome after total elbow arthroplasty: a retrospective study of 167 procedures performed from 1981 to 2008.

BACKGROUND: Total elbow arthroplasties (TEAs) are traditionally grouped into linked and unlinked design. The aim was to analyze the difference in clinical outcomes after TEA based on implant design and indication for surgery and to evaluate primary and revision TEAs. METHODS: A total of 167 TEAs (126 primary and 41 revision TEAs) in 141 patients were evaluated with patient-reported outcome measure by the Oxford Elbow Score (OES) and clinically assessed with the Mayo Elbow Performance Score (MEPS), range of motion (ROM), and standard radiographs. RESULTS: The mean follow-up was 10.5 years for primary and 7.5 years for revision TEAs. There was no difference in OES or MEPS between linked and unlinked primary TEAs. The OES score in the social-psychological domain was significantly lower in TEAs performed due to fracture (67) compared with rheumatoid arthritis (81; P = .025). ROM in extension-flexion was 116° for primary linked TEAs compared with 110° for primary unlinked TEAs (P = .02). Revision TEAs were associated with a poorer outcome in OES, MEPS, and ROM compared with primary TEAs. Radiographic signs of loosening were seen in 15 primary and 7 revision TEAs at follow-up. CONCLUSIONS: We found no clinically significant differences in outcomes after linked or unlinked TEAs. Patients with TEAs due to fracture had poorer social-psychological results than rheumatoid arthritis patients. The results after revision surgery were significantly inferior compared with primary procedures. The OES contributes to the evaluations of the outcome after TEA surgery with a nuanced picture of the patient's perception.

Single-dose pharmacokinetics of vancomycin in porcine cancellous and cortical bone determined by microdialysis.

High treatment failure rates and the need for prolonged antimicrobial therapy for osteomyelitis and implant-associated infections suggest that antimicrobial bone penetration may be incomplete. Assessment of the bone pharmacokinetics of antimicrobials is challenged by a lack of validated methods. In this study, 1000 mg of vancomycin was administered as a single dose over 100 min to eight female pigs. Plasma, subcutaneous adipose tissue (SCAT) and bone pharmacokinetics were investigated over 12 h. Microdialysis was applied for collection of samples in bone and SCAT. The vancomycin concentration in microdialysates was determined using ultra-high performance liquid chromatography, whilst the free plasma concentration was determined using Cobas c501. The mean (95% CI) area under the concentration-time curve (AUC(0-last); minµg/mL) was 9375 (7445-11304), 9304 (7374-11233), 5998 (3955-8040) and 3451 (1522-5381) for plasma, SCAT, and cancellous and cortical bone, respectively (ANOVA P-value < 0.001). Both cortical and cancellous bone AUC0-last were lower than that of free plasma (P < 0.01). Peak drug concentrations (C(max)) in cortical and cancellous bone were also significantly lower than that of free plasma (P < 0.001). Moreover, both AUC(0-last) and C(max) were significantly lower in cortical bone than in cancellous bone (P < 0.025). Bone penetration of vancomycin was found to be incomplete and delayed. Significant differences in pharmacokinetics between cancellous and cortical bone suggest that bone may not be considered as one compartment. Future studies should focus on validating the applicability of microdialysis for assessment of antimicrobial bone pharmacokinetics.

Risk factors for the need of hip arthroscopy following periacetabular osteotomy.

Despite the frequency of labral tears in symptomatic developmental dysplasia of the hip, no consensus exists regarding the treatment of coexisting dysplasia of the hip and tearing of the acetabular labrum. The purpose of this prospective, MR arthrography (MRA) based 2-year follow-up study was to identify risk factors predicting the need for a hip arthroscopy (HA) after periacetabular osteotomy (PAO). Ninety-nine patients (104 hips) scheduled for PAO were evaluated preoperatively and at 2-year follow-up. MRA was performed in all patients prior to PAO. At follow-up, patients were divided into a non-arthroscopy and arthroscopy group. The two groups were compared clinical and radiological, and risk factors for HA after PAO were calculated. Patient reported outcome measures (WOMAC, Oxford Hip and SF36) were filled out before PAO and at follow-up. Ninety-five hips (91.3%) were evaluated. Twenty-six hips (27%) required an arthroscopy within 2 years of the PAO. Risk factors were preoperative borderline dysplasia, acetabular retroversion and complete labral detachment. Labral tearing, degeneration or hypertrophy did not negatively affect the outcome of PAO. Patients not requiring an arthroscopy had a statistically significant better outcome measured by patients reported outcome measures. After PAO, 27% of the hips needed intra-articular assessment. Conventional radiographs and MRA analysis can be used to identify predictors for patients requiring HA after PAO. At 2-year follow-up, the clinical outcome improved in all patients. However, those patients who had no need of a HA after their PAO had superior results.

Is bigger always better? A nationwide study of hip fracture unit volume, 30-day mortality, quality of in-hospital care, and length of hospital stay.

BACKGROUND: Higher patient volume has been linked with better clinical outcomes for a range of surgical procedures; however, little is known about the impact of volume on quality of care and clinical outcome among patients with hip fracture. OBJECTIVES: To examine the association between hip fracture patient volume and 30-day mortality, quality of in-hospital care, time to surgery, and length of hospital stay, respectively. DESIGN: Population-based follow-up study. SUBJECTS: Using prospectively collected data from the Danish Multidisciplinary Hip Fracture Registry, we identified 12,065 patients 65 years and older who were admitted with a hip fracture between March 1, 2010 and November 30, 2011. MEASURES: Patient volume was divided into 3 groups; ≤ 151 hip fracture admissions per year, 152-350, and ≥ 351 admissions per year based on the distribution of the hospitals and to ensure a reasonable proportion of hospitals in each category. Data were analyzed using regression techniques while controlling for potential confounders. RESULTS: Admission to high-volume units was associated with higher 30-day mortality [adjusted odds ratio (OR)=1.37 (95% confidence interval (CI), 1.14-1.64)] and a longer length of hospital stay (adjusted relative time=1.25 (95% CI, 1.02-1.52)]. Furthermore, patients had lower odds for being mobilized within 24 hours postoperatively and for receiving basic mobility assessment and a postdischarge rehabilitation program. Time to surgery was nonsignificantly increased [adjusted relative time=1.25 (95% CI, 0.99-1.58)]. CONCLUSIONS: Patients admitted to high-volume hip fracture units had higher mortality rates, received a lower quality of in-hospital care, and had longer length of hospital stay.

Implant survival after total elbow arthroplasty: a retrospective study of 324 procedures performed from 1980 to 2008.

BACKGROUND: Total elbow arthroplasty (TEA) is an established treatment for late-stage arthritis of the elbow. Indications have expanded to osteoarthritis and nonunion in distal humeral fractures. Information on implant survival and risk factors for revision is still sparse. The aim of this study was to evaluate implant survival and risk factors for revision of TEAs inserted in patients in the eastern part of Denmark in the period from 1980 until 2008. MATERIAL AND METHODS: The Danish National Patient Register provided personal identification numbers for patients who underwent TEA procedures from 1980 until 2008. On the basis of a review of medical reports and linkage to the National Patient Register, we calculated revision rates and evaluated potential risk factors for revision, including, age, sex, period, indication for TEA, and implant design. RESULTS: We evaluated 324 primary TEA procedures in 234 patients at a mean follow-up of 8.7 years (range, 0-27 years). The overall 5-year survival was 90% (95% confidence interval [CI], 88%-94%), and 10-year survival was 81% (95% CI, 76%-86%). TEAs performed with the unlinked design had a relative risk of revision of 1.9 (95% CI, 1.1-3.2) compared with the linked design. Fracture sequelae was associated with a relative risk of revision of 1.9 (95% CI, 1.05-3.45). CONCLUSIONS: We found acceptable implant survival rates after 5 and 10 years, with a higher revision rate for the unlinked design and primary TEA due to fracture sequelae. Patient-related outcome measures should be included in future studies for further elaboration of the outcomes after TEA. LEVEL OF EVIDENCE: Level III, Retrospective cohort design, treatment study.