Diagnosing popliteofibular ligament injuries in anterior cruciate ligament-injured knees: A prospective magnetic resonance imaging study investigating the inter- and intraobserver reliability of identification of the popliteofibular ligament.

Purpose: The aim of our study was to investigate the intra- and interobserver reliability for the identification of the popliteofibular ligament (PFL) in magnetic resonance imaging (MRI) scans in patients with an anterior cruciate ligament (ACL) injury and ascertain the prevalence of PFL tears in ACL-injured knees without clinically high-grade posterolateral corner injury. Methods: MRI readings were performed retrospectively by two surgeons on 84 patients who underwent ACL reconstruction in our department. The presence of the PFL on both sagittal and coronal images as well as the presence of PFL tears was noted. Readings were repeated 6 weeks later for one observer. The κ value was calculated to determine the intra- and interobserver reliability for identification of the PFL and the prevalence of PFL tears was ascertained. Results: The PFL was visualized in 90.5%-91.7% of MRI scans. The intra- and interobserver reliability of visualizing the PFL on MRI had an κ value of 0.63 and 0.66 (substantially reliable), respectively. The intraobserver reliability for identification of PFL tears had an κ value of 0.26 (fair reliability). We found a 4.8% prevalence of PFL tears in ACL-injured knees. Conclusions: There is substantially reliable intra- and interobserver reliability for the identification of the PFL on MRI scans but only fair reliability for the identification of PFL tears. A 4.8% prevalence of PFL tears in ACL-injured knees without clinically confirmed high-grade posterolateral corner injury can be observed in our series. Level of Evidence: Level IV.

Drilling the tibial tunnel in an arthroscopic popliteus bypass from the anteromedial tibial cortex decreases risk of popliteal vascular injury.

Purpose: Drilling the tibial tunnel in tibiofibular-based posterolateral corner (PLC) reconstructions is usually performed with a starting point from Gerdy's tubercle. Drilling the tunnel starting from the anteromedial tibial cortex could reduce the risk of popliteal neurovascular (PNV) injury. The purpose of this study is to assess the distance on Magnetic Resonance Imaging Scans (MRI) of the PNV bundle and peroneal nerve (PN) to these two different tunnel trajectories. Methods: A total of 87 MRI scans were assessed. The ideal exit point of the tibial tunnel in PLC reconstructions was marked. We added 10 mm from this point in a straight posterior and in an oblique trajectory, mimicking the two different tunnel trajectories and measured the distance to the PNV bundle and PN from these two points. Results: The mean distance of the tip of the guide wire drilled with a trajectory from Gerdy's tubercle to the PNV bundle and the peroneal nerve was respectively 13.2 mm (SD = 3.96) and 17.7 mm (SD = 4.39). The mean distance of the tip of the guide wire drilled with a trajectory from the anteromedial tibial cortex to the PNV bundle and the PN was respectively 19.6 mm (SD = 4.19) and 12.2 mm (SD = 3.96).). Drilling in a trajectory from the anteromedial tibial cortex significantly increases the distance to the PNV bundle (p < 0.001). Conclusion: Tibial tunnel drilling in a tibiofibular based PLC reconstruction from the anteromedial tibial cortex significantly increases the distance to the popliteal artery but with a decreased distance to the peroneal nerve. Level of evidence: level IV.

Intra- and interobserver reliability of two classification systems for posterolateral tibial plateau fractures in the setting of an ACL rupture.

Background: Posterolateral tibial plateau impaction fractures occur frequently associated with anterior cruciate ligament (ACL) tears. Some authors advocate operative treatment of high-grade impaction fractures, which has led to the development of classification systems. Our study aims (1) to describe and compare the intra- and interobserver reliability of the two most used classifications and (2) to assess correlations between the grade of bony posterolateral tibial injury, patient characteristics and short-to mid-term revision rate after ACL reconstruction. Materials and methods: In a retrospective series of 163 patients who underwent ACL reconstruction, two reviewers independently evaluated the preoperative MRI scans. Conform the Menzdorf and Bernholt classification the presence and grade of an associated posterolateral impaction fracture were assessed. Statistical analyses were performed to test for both study hypotheses. Results: 171 primary ACL cases were evaluated. Mean follow-up time was 41 months (range 12-154, SD = 17.1). Mean age was 32 years (range 13-59, SD = 12). Posterolateral impaction fractures were present in 111 (64.9 %) and 120 (70.0 %) cases, according to the Menzdorf and Bernholt classification. A Segond fracture was present in 19 (11.1 %) cases. Kappa value was 0.47 for intra- and 0.52 for the interobserver reliability for the Menzdorf classification (moderate reliability). For the Bernholt classification kappa values were 0.66 and 0.61, respectively (good reliability). A Segond fracture correlated significantly with the presence of a posterolateral impaction fracture (p < 0.05). A significant association was present between patients necessitating ACL revision surgery and patients for whom operative intervention for the posterolateral impression was advised following the Menzdorf classification (p < 0.001). Conclusion: Inter- and intraobserver reliability testing for classifying posterolateral tibial fractures resulted in moderate to good reliability. High-grade posterolateral tibial fractures should be identified, selective treatment should be considered as they are associated with higher revision rates after ACL reconstruction if left untreated.

Most Publications Regarding Arthroscopic Treatment of Posterolateral Corner Injuries of the Knee Have a Low Level of Evidence and Provide Limited Information to Determine the Most Effective Treatment.

Purpose: To examine the Level of Evidence and overall quality of studies addressing arthroscopic posterolateral corner reconstructions of the knee. Methods: A search was performed using the PubMed/Medline, Web of Science, and Google Scholar databases for all studies investigating arthroscopic treatment of posterolateral corner injuries of the knee. Studies reporting outcomes or describing arthroscopic techniques for treatment of posterolateral corner injuries of the knee were the focus of this analysis. Clinical as well as biomechanical and cadaveric studies were included. Studies only investigating open techniques were excluded. Two independent reviewers determined the level of evidence for each included study using the criteria established by the Journal of Bone and Joint Surgery and scored each clinical study from 0 to 100 based on 10 criteria from the modified Coleman Methodology Score. Results: Twenty-four studies matched the inclusion criteria. There were 6 cadaveric technique descriptions, 6 clinical technique descriptions, 3 biomechanical studies, 4 technical repair descriptions, and 5 clinical outcome studies. Thirty-eight percent of all studies were of Level V evidence. Fifty percent of studies were of Level IV evidence, and 12% of studies were of Level III evidence. The mean modified Coleman Methodology Score for the clinical studies was 43 ± 11.4, which is regarded as poor, mainly due to the limited number of patients and the retrospective nature of the studies. Conclusions: Most studies addressing arthroscopic posterolateral corner reconstruction of the knee are of low level of evidence and provide limited information about the best treatment options. Clinical Relevance: The number of publications on arthroscopic posterolateral corner reconstruction techniques continues to rise. This systematic review evaluates the level of evidence of these studies.

Isolated femoral avulsion of the popliteus tendon: a systematic review of the literature.

The popliteus tendon is an important part of the posterolateral corner of the knee. Isolated injuries to the posterolateral corner are very rare, as most injuries occur in multiligamentous knee trauma. Purely isolated popliteus tendon injuries are even more rare. There is very little evidence for treatment of isolated popliteus tendon avulsion injuries. The aim of this systematic review is to report on all publications regarding isolated popliteus tendon avulsion injuries and hopefully provide some guidance for future treatment algorithms. A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Studies were included if they documented isolated popliteus tendon avulsion injuries. Exclusion criteria were studies with popliteus injuries in combination with other knee ligamentous injuries and popliteus tendon injuries other than femoral avulsion injuries. Twenty-eight studies were included which mentioned in total 38 patients with isolated popliteus tendon avulsion injuries. 24 patients (63%) were treated operatively. 3 (8%) patients were diagnosed arthroscopically but did not receive any surgical treatment. 9 patients (24%) were treated conservatively. In two publications, there was no mention of treatment. We found no clear recommendations in the literature for treatment of this rare injury.

Reversible room temperature ammonia gas absorption in pore water of microporous silica-alumina for sensing applications.

Microporous silica and silica-alumina powders exhibit a reversible uptake and release of ammonia gas from water vapor containing gas mixtures at ambient temperature, with capacities of 0.9 and 2.0 mmol g-1 in the presence of 100 ppm and 1000 ppm NH3, respectively. The ammonia trapping mechanism was revealed using a combination of direct excitation 1H MAS, 1H-1H EXSY and 1H DQ-SQ NMR spectroscopy, indicating that the major part of the captured ammonia is blended in the hydrogen bonded water network in the pores of the adsorbent. A small fraction is irreversibly bound as result of protonation and chemisorption. While common ammonia adsorbents need thermal regeneration, microporous silica-alumina can be regenerated by sweeping with dry gas at ambient temperature, desorbing the physisorbed fraction together with occluded water. As carbon dioxide does not interfere with the ammonia absorption process, this reversible absorption process of ammonia gas at ambient temperature is particularly attractive for sensor applications.

Tibial Component In Total Knee Replacement :The Effect Of Overhang And Sizing On Outcome.

The aim of this study was to find a relationship between tibial overhang, malpositioning and oversizing, and the functional outcome. 188 patients were included in this retrospective study. All patients completed an Oxford knee score questionnaire at mean followup of 5 years. Anteroposterior radiographs of the total knee replacements were reviewed for medial and lateral overhang and oversizing. Lateral overhang was seen in 32.9% of patients with a mean Oxford knee score of 24.7. However lateral overhang proved no significant correlation with the functional outcome. Oversizing was seen in 31.9% of patients and, with a mean of 25.6, oversizing did have a correlation with Oxford Knee score. This study confirms that neither medial or lateral overhang of the tibial component influences functional outcome, independent of the severity of overhang. Oversizing the tibial component however, does show worse functional outcome scores at a 5 year review.

Effect of femoro-tibial component size mismatch on outcome in primary total knee replacement.

BACKGROUND: Most total knee arthroplasty systems allow a degree of femoro-tibial component size mismatch. We aim to investigate the influence of size mismatch on outcome after primary total knee arthroplasty. METHODS: We reviewed 332 patients with cruciate-retaining Genesis II total knee arthroplasty with regard to femoro-tibial component size mismatch and Oxford Knee Score (OKS). We evaluated effects of Body Mass Index, gender and patellar procedure. Minimum follow-up is five years. We divided patients into four groups (tibial component larger than femoral component, no mismatch, femoral component one size larger and femoral component two sizes larger than tibial component). RESULTS: There was no statistically significant difference in OKS between the four groups. Size mismatch did not have a statistical significant effect on OKS in a multivariate analysis. Women had mismatched components in 66% of all cases and men in 40% of all cases. CONCLUSIONS: Our study showed no statistically significant effect of femoro-tibial size mismatch on outcome after total knee replacement. Compared to men, women tend to have more component size mismatch. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Reliability analysis of glenoid component inclination measurements on postoperative radiographs and computed tomography-based 3D models in total and reversed shoulder arthroplasty patients.

BACKGROUND: Only a few articles describe the reproducibility and clinical feasibility of glenoid inclination measurements on conventional radiographs, and none of them validated their method in shoulder arthroplasty cases. From a clinical point of view, the angle measured between the supraspinatus fossa and the glenoid fossa line (angle ß) appears to be the most interesting angle to assess glenoid inclination. This study aimed to validate the angle ß in shoulder arthroplasty patients to facilitate the assessment of glenoid component inclination. MATERIALS AND METHODS: Seventeen patients who underwent total or reverse shoulder arthroplasty were evaluated. The angle ß was measured by 2 independent observers on postoperative radiographs and 3-dimensional (3D) models. The interobserver variability and accuracy of angle ß were analyzed by calculating the intraclass correlation coefficient (ICC) and by generating Bland-Altman plots. RESULTS: The angle ß showed a good interobserver variability (ICC = 0.971 for radiographs, ICC = 0.980 for 3D models) and a good agreement between the radiographic and 3D measurements (ICC = 0.904 for observer 1 and ICC = 0.908 for observer 2). Bland-Altman plots demonstrated that in 95% of the measurements on radiographs, the error will be <10. In the investigated population, 85% showed an error <6. CONCLUSION: This study demonstrates that angle ß can be measured on radiographs to assess glenoid component inclination in total and reverse shoulder arthroplasty, but clinicians and researchers should keep in mind that measurement errors of 10° may occur in a minority of cases.

Patient-specific instrument guidance of glenoid component implantation reduces inclination variability in total and reverse shoulder arthroplasty.

BACKGROUND: The aim of this study was to assess the influence of 3-dimensional (3D) preoperative planning and patient-specific instrument (PSI) guidance of glenoid component positioning on its inclination in total shoulder arthroplasty (TSA) and reverse shoulder arthroplasty (RSA). MATERIALS AND METHODS: Thirty-six shoulder arthroplasties (12 TSAs, 24 RSAs) were analyzed, of which 18 procedures (6 TSAs, 12 RSAs) were executed using preoperative 3D planning and patient-specific guides to position the central guide pin for glenoid component implantation. In 9 cases, the glenoid anatomy was severely distorted through wear or previous surgery. The inclination of the glenoid component was measured by 2 observers, using the angle between the glenoid baseplate and the floor of the supraspinatus fossa (angle ß) on postoperative radiographs. RESULTS: For TSA, the average angle ß was 74 ± 9 in the PSI group and 86 ± 12 in the non-PSI group; for RSA, the average angle ß was 83 ± 7 in the PSI group and 90 ± 17 in the non-PSI group. Extreme angles ß, which represent extreme values of glenoid component inclination, are more likely to occur in the non-PSI group than in the PSI group (P < .001 for TSA; P = .02 for RSA). CONCLUSIONS: The3D preoperative surgical planning and PSI guidance reduce variability in glenoid component inclination and avoid extreme inclination errors for TSA and RSA.

Remodeling of the Proximal Tibia Subsequent to Bone Graft Harvest: Postoperative CT Study.

BACKGROUND: Proximal tibia bone autograft (PTBG) is regularly used in reconstructive foot, ankle, and maxillofacial surgery. Although many surgeons prefer PTBG rather than the conventional iliac crest, little is known about the remodeling capacity of the proximal tibia after harvesting cancellous bone. METHODS: Via bilateral postoperative computed tomography of 17 harvesting sites, comparing the defect side with the healthy side, we measured the repair capacity of the proximal tibia in response to bone defect created by the harvest at medium-term follow-up (mean 29 months; range, 7-55 months). RESULTS: 16 of 17 (94%) cortical defects showed complete consolidation. Cancellous remodeling was graded 0 to 3, with 2 defects showing complete remodeling (grade 3), 4 defects partial remodeling (more than 50%), 8 defects partial remodeling (less than 50%) and 3 defects no remodeling at all (grade 0). CONCLUSION: The proximal tibia has the potential to form new cancellous bone after cancellous bone graft harvesting. More data are required to identify possible variables influencing this remodeling capacity. When performing knee surgery, knee surgeons should take into account the relatively small defect size and the consolidation of the cortical window after proximal tibia bone harvesting. LEVEL OF EVIDENCE: Level IV, case series.

Computer navigation and patient-specific instrumentation in shoulder arthroplasty.

Longevity of total anatomic and reversed shoulder arthroplasty largely depends on accurate correction of glenoid deformity and correct positioning and fixation of the glenoid component. However, the morphology of the scapula is inconsistent, varying degrees of osteoarthritis cause numerous anatomic changes, and standard 2-dimensional imaging and standard surgical instrumentation are imprecise for preoperative planning and execution of glenoid reconstruction. Recently, various authors have shown that preoperative 3-dimensional surgical planning and computer navigation technology may increase the accuracy and repeatability of the implantation of the glenoid component, especially for the position and orientation of the glenosphere and screws in reversed arthroplasty. These novel techniques may allow the surgeon to better define the preoperative deformity, select the optimal implant position, and then accurately execute the plan at the time of surgery. Future studies are needed to determine the long-term effect on functional outcome and cost-effectiveness of computer-assisted technology in shoulder arthroplasty.

Entropy-driven chemisorption of NO(x) on phosphotungstic acid.

Free-energy calculations indicated that the NO(x) adsorption process on heteropolyacids is entropy-driven, as more gas molecules are released than adsorbed by substitution of H(5)O(2)(+) with NO(+) species. P yellow, W light blue, O red, H pink, N small dark blue spheres.

Validation of a CT-based determination of the glenohumeral index.

The amount of bony support by the glenoid can be determined using the glenohumeral index, i.e. the maximum anteroposterior (AP) diameter of the humeral head divided by the maximum AP dimension of the glenoid. This index has been described theoretically, but has never been validated in practice. In this study we used 20 cadaver shoulders to determine the glenohumeral index in two different ways. One method evaluated the glenohumeral index on a CT scan of the shoulders. The second method determined the anatomical glenohumeral index of the same shoulders by direct measurement of anatomical specimens using a digital caliper. All CT and caliper measurements were repeated by three different investigators. We used the Wilcoxon Signed Rank Test, to calculate the statistical significance of intra-observer and inter-observer differences in measurements on CT and with the caliper. Statistical analysis showed no significant differences between CT scan and caliper measurements for each investigator separately, but we found a statistically significant inter-observer variability concerning the caliper measurements obtained by two different investigators. This study demonstrates that a two-dimensional CT scan of the shoulder is a reliable and very accurate tool to calculate the glenohumeral index, as the values measured for the AP diameter of the humeral head and the AP dimension of the glenoid compare well with those measured in vitro on anatomical specimens.

Closed total talus dislocation: a case report.

Total dislocation of the talus is caused by a high-energy trauma, that dislocates the talus from all its surrounding articulations. Most cases reported are open talus dislocations; closed dislocations are rarely seen. Complications include avascular necrosis, posttraumatic osteoarthritis and infection. The vascularisation of the talus is delicate and the soft tissue attachments surrounding the talus are important for the blood supply. Closed talus dislocations, closed reduction and careful surgical dissection in case of open reduction respect more soft tissue attachments and potentially reduce the incidence of avascular of necrosis. We describe the case of a 46-year old male patient who sustained a closed total dislocation of the right talus associated with small fractures of the lateral and medial malleolus. The talus could not be reduced by closed means. The malleolar fractures were treated by open reduction and internal fixation.

Recurrent chordoma of the L2 vertebra: a case report.

Chordoma is a rare slow-growing, locally invasive primary malignant bone tumour arising from notochord remnants. It is characterised by a high local recurrence rate. Most chordomas (60%) are found in the sacrococcygeal region: only 15% originate in the mobile spine. CT-scan and MRI can help evaluate the tumour extension. En bloc resection of the tumour mass is the standard treatment. The main prognostic factor is tumour-negative surgical margins. Due to the location of spinal chordomas, adjacent to vital neural and vascular structures, this can be difficult to achieve. Therefore radiotherapy has been used when adequate excision is not possible and in case of local recurrence. We report the case of a 72-year-old female with a recurrent chordoma of the L2 vertebra, previously treated with resection and radiotherapy. The recurrent chordoma was resected using a right-sided thoraco-phreno-laparotomy as the tumour could not be resected using the left anterior approach or posterior approach due to extensive fibrosis following surgery and radiotherapy.