Introduction
Although there is increasing evidence for the successful use of local vancomycin applied by soaked compresses during ACL reconstruction, there are still little data on its ...microbiological and biomechanical effects. Furthermore, exact dosage of vancomycin with respect to tendon stability and microbiological effectivity is still unknown.
Materials and methods
63 porcine flexor digitorum profundus tendons were harvested under sterile conditions from fresh cadaver legs. After contamination with
Staphylococcus epidermidis
(
S. epidermidis
), tendons were wrapped into sterile compresses moistened with different concentrations of vancomycin for 10 or 20 min. Sterile sodium chloride was used for control. After treatment, tendons were rolled onto blood-agar plates to test for residual bacterial contamination and tested for maximum load and stiffness using a uniaxial testing device with cryo-clamps for tendon fixation. Agar plates were checked after 1 week of culture at 36 °C for signs of bacterial growth.
Results
When applying vancomycin for only 10 min, bacterial contamination was found in all dosage groups ranging from 28.6% contamination (
n
= 2 of 7 tendons) when using 10 mg/ml up to 85.7% (
n
= 6 of 7 tendons) when using 1 mg/ml. Applying vancomycin-soaked compresses for 20 min, bacterial contamination was still found in the groups using 1 mg/ml and 2.5 mg/ml (contamination rate 85.7 and 42.9% respectively). When using 5 mg/ml and 10 mg/ml, no bacterial contamination could be perceived after 7 days of culture. With regard to biomechanical properties, no differences were found regarding maximum load or Young’s modulus between groups.
Conclusions
This study showed no signs of biomechanical impairment of porcine flexor tendons after the use of vancomycin wraps with concentration ranging from 1 to 10 mg/ml for 10 or 20 min at a time zero testing. Contamination with
S. epidermidis
was cleansed in 100% of tendons when using at least 5 mg/ml of vancomycin for 20 min.
Purpose
The preservation of meniscal structure and function after segmental meniscal loss is of crucial importance to prevent early development of osteoarthritis. Implantation of artificial meniscal ...implants has been reported as a feasible treatment option. The purpose of this study was to assess the clinical and magnetic resonance imaging (MRI) results 4 years after implantation of a polyurethane scaffold for chronic segmental medial meniscus deficiency following partial medial meniscectomy.
Methods
Eighteen patients received arthroscopic implantation of an Actifit
®
polyurethane meniscal implant (Orteq Sports Medicine, London, UK) for deficiency of the medial meniscus. Patients were followed at 6, 12, 24, and 48 months. Clinical outcome was assessed using established patient-reported outcome scores (KOOS, KSS, UCLA Activity Scale, VAS for pain). Radiological outcome was quantified by MRI scans after 6, 12, 24, and 48 months evaluating scaffold morphology, tissue integration, and status of the articular cartilage as well as signs of inflammation.
Results
Median patient age was 32.5 years (range 17–49 years) with a median meniscal defect size of 44.5 mm (range 35–62 mm). Continuing improvement of the VAS and KSS Knee and Function Scores could be observed after 48 months compared to baseline, whereas improvement of the activity level according to UCLA continued only up to 24 months and decreased from there on. The KOOS Score showed significant improvement in all dimensions. MRI scans showed reappearance of bone bruises in two patients with scaffold extrusion. No significant changes in the articular cartilage could be perceived.
Conclusion
Arthroscopic treatment for patients with chronic segmental meniscal loss using a polyurethane meniscal implant can achieve sustainable midterm results regarding pain reduction and knee function.
Level of evidence
IV.
Purpose
Balancing mobile-bearing (MB) unicondylar knee arthroplasty (UKA) is challenging. If performed improperly, potential complications include pain, implant loosening, or progression of ...osteoarthritis in the preserved compartment. The purpose of this study was to document effects of improper balancing on knee kinematics and joint contact stress. It was hypothesized that over-stuffing would lead to more valgus and higher lateral contact force.
Methods
Seven fresh-frozen cadaver legs were mounted in a kinematic rig that applied three motion patterns to the specimens: passive flexion–extension, open chain extension, and squatting. During testing, an infrared camera system recorded the trajectories of markers rigidly attached to femur and tibia, while a pressure sensor measured contact pressure in the lateral compartment. Prior computer tomography scans allowed identification of coordinate frames of the bones and calculations of anatomical rotations and translations. Collateral ligament strains were calculated, and quadriceps forces recorded. Following testing on the native knee, a medial MB UKA was implanted in each specimen and all motion trials were repeated. Three inlay thicknesses were tested to simulate optimal balancing as well as under- (1 mm thinner) and over-stuffing (1 mm thicker) of the medial compartment relative to the optimal thickness.
Results
Under-stuffing of the medial compartment leads to kinematics closest to the native knee. Subjectively balanced and over-stuffed MB UKA knees were in more valgus. Lateral peak contact stress was higher from mid- to deep flexion following UKA in all three tested states; however, these results were not significant. Peak strain in the superficial medial collateral ligament (sMCL) was significantly higher in MB UKA, regardless of the inlay thickness mainly in mid-flexion. Inlay thickness had no significant impact on measured quadriceps force during squatting.
Conclusion
The results underline the importance of optimal balancing. Over-stuffing should be avoided as it results in the largest kinematic changes relative to the native condition and induces higher strains in the sMCL. Based on the kinematic findings, it is advisable to use thinner inlays, as long as this is not compromising stability or risking inlay luxation.
The anterolateral ligament of the knee (ALL) has caused a lot of rumors in orthopaedics these days. The structure that was first described by Segond back in 1879 has experienced a long history of ...anatomic descriptions and speculations until its rediscovery by Claes in 2013. Its biomechanical properties and function have been examined recently, but are not yet fully understood. While the structure seems to act as a limiter of internal rotation and lateral meniscal extrusion its possible proprioceptive effect remains questionable. Its contribution to the pivot shift phenomenon has been uncovered in parts, therefore it has been recognized that a concomitant anterolateral stabilization together with ACL reconstruction may aid in prevention of postoperative instability after severe ligamentous knee damages. However, there are a lot of different methods to perform this procedure and the clinical outcome has yet to be examined. This concise review will give an overview on the present literature to outline the long history of the ALL under its different names, its anatomic variances and topography as well as on histologic examinations, imaging modalities, arthroscopic aspects and methods for a possible anterolateral stabilization of the knee joint.
Kinematics of a bicruciate-retaining total knee arthroplasty Heyse, Thomas J.; Slane, Joshua; Peersman, Geert ...
Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA,
06/2017, Letnik:
25, Številka:
6
Journal Article
Recenzirano
Purpose
The recently reintroduced bicruciate-retaining Total Knee Arthroplasty (BCR TKA) is an interesting approach in the quest for close replication of knee joint biomechanics and kinematics closer ...to the native knee. Therefore, this study aimed at providing a detailed biomechanical view on the functional resemblance of BCR TKA to the native knee joint.
Methods
Seven fresh-frozen full leg cadaver specimens (76 ± 10 year) were mounted in a 6 degrees-of-freedom kinematic rig that applied a dynamic squatting motion knee flexion. Two motion patterns were performed pre- and post-implantation of a fixed bearing BCR TKA: passive flexion–extension and squatting while an infrared camera system tracked the location of reflective markers attached to the tibia and femur. Additionally, specimen laxity was assessed using Lachman tests and varus/valgus stress tests in triplicate.
Results
Overall, differences in tibiofemoral kinematics between native knee and BCR TKA were small. Some minor differences appeared under the load of a squat: less internal tibial rotation and some minor paradoxical anterior translation of the medial femoral condyle during mid-flexion. BCR TKA may slightly elevate the joint line. Knee laxity as measured by the Lachman and varus/valgus tests was not significantly influenced by BCR TKA implantation.
Conclusion
As both cruciate ligaments are preserved with BCR TKA the unloaded knee closely resembles native knee kinematics including preserving the rollback mechanism. The loss of the conforming anatomy of menisci and tibial cartilage and replacement via a relatively flat polyethylene inlay may account for the loss of tibial internal rotation and the slight paradoxical AP motion of the medial femoral condyle with BCR TKA. This phenomenon reproduces findings made earlier with fixed bearing unicondylar knee arthroplasty.
Ankle tape is widely used by athletes to prevent ankle sprain. Although there is growing evidence that ankle tape improve joint position sense, but yet it is not clear even if tape improve joint ...position sense after muscle fatigue, because fatigue impair joint position sense and raise the risk of ankle sprain. The aim of this study is to examine the effect of ankle tape on joint position sense after local muscle fatigue.
This trial is a randomized controlled trial. 34 healthy subjects participated in this trial. Subjects were randomized distributed into two groups: with tape and without tape. Active and passive absolute error and variable error mean values for two target positions of the ankle joint (15° inversions and inversion minus 5°) before and after fatigue protocol consisted of 30 consecutive maximal concentric/concentric contractions of the ankle evertors and invertors. In this trail joint position sense for all subjects was assessed using The Biodex System isokinetic dynamometer 3, this system is used also for fatigue protocol.
For the variable error (VE), significant mean effect was found for active joint position sense in 15° of inversion after muscle fatigue (P < 0, 05). It was a significant decrease in the work in the last third of inversion detected (P < 0, 05). There was no significant main effect found for fatigue index of eversion.
Ankle tape can improve joint position sense at the fatigue session when joint position sense becomes worse. As a result, ankle tape may be useful to prevent ankle sprain during playing sports. We suggest athletes and individuals at risk of ankle sprain to apply taping before high-load activity.
The study was retrospectively registered on the ISRCTN registry with study ID ISRCTN30042335 on 12th December 2017.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Closing-wedge high tibial osteotomy (HTO) is successful for the treatment of medial osteoarthritis with varus malalignment. Preoperative risk factors for HTO failure are still controversial. The aim ...of this study was to elucidate the outcome and assess the influence of risk factors on long term HTO survival.
199 patients were retrospectively studied with a mean follow-up period of 9.6 years after HTO. HTO failure was defined as the need for conversion to TKA. Survival was analyzed with the Kaplan-Meier method. Knee function was evaluated by the Hospital for Special Surgery (HSS) score. HTO-associated complications were also assessed. Univariate, multivariate, and logistic regression analysis were performed to evaluate the influence of age, gender, BMI, preoperative Kellgren-Lawrence osteoarthritis grade, and varus angle on HTO failure.
39 complications were recorded. Thus far, 36 HTOs were converted to TKA. The survival of HTO was 84% after 9.6 years. Knee function was considered excellent or good in 64% of patients. A significant preoperative risk factor for HTO failure was osteoarthritis, Kellgren-Lawrence grade >2.
HTO provides good clinical results in long-term follow-up. Preoperative osteoarthritis Kellgren-Lawrence grade >2 is a significant predictive risk factor for HTO failure. Results of HTO may be improved by careful patient selection. Complications associated with HTO should not be underestimated.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Navigation was introduced into total knee arthroplasty (TKA) to improve accuracy of component position, function and survival of implants. This study was designed to assess the outcome of navigated ...TKA in comparison with conventional implantation with the focus on rotational component position and clinical mid-term results.
In a prospectively randomized single-blinded approach, 90 patients with primary gonarthrosis were assigned to three different groups. Thirty patients each were assigned to NexGen LPS without and with navigation (groups 1 and 2), and 30 patients to navigation with the Stryker Scorpio PS (group 3). The navigation system used was the imageless Stryker KneeTrac, version 1.0. Clinical outcome was assessed by a blinded observer applying the Knee Society Score (KSS) and a visual analogue scale (VAS) for pain. CT scans and radiographs were conducted prior to and 12 weeks after index surgery.
Seventy-nine patients were available for clinical evaluation at 3 ± 0.4 years follow-up. Four implants had to be revised for early loosening or infection (4.4%). Four patients had died and three patients were not able to follow the invitation for clinical assessment. Functional results in the KSS were significantly lower after navigated TKA. Operation time and incisions with navigation were significantly longer. Significantly less radiological outliers with navigation were found for coronal alignment of the femur, only.
In this series, no beneficial effect for navigation in TKA could be shown assessing clinical data, as functional results in the presented series seemed to be lower after first generation navigated TKA. The clinical mid- to long-term value of navigation remains to be evaluated in larger patient series or meta-analyses at longer follow-up.
DRKS 00000430.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cemental tear is defined as cementum fragment completely or partially detached from the root surface, and it has been associated with localized rapid periodontal breakdown. Although history of trauma ...and/or attrition may be risk factors, the etiopathology of cemental tear remains unknown. This case series aims to discuss the clinical, radiographic and histopathologic features of cemental tears to aid clinicians in making differential diagnosis. Three teeth from three patients presenting a periradicular lesion underwent an exploratory surgery to determine the cause and provide treatment. Soft and hard tissue biopsies were obtained from each lesion and forwarded for histopathologic evaluation. Two patients received a guided tissue regeneration (GTR) procedure, which allowed the tooth to be retained. One patient received an extraction with simultaneous guided bone regeneration (GBR) due to a hopeless prognosis of the tooth. The results after histopathologic evaluation yielded a final diagnosis of cemental tear for all three patients. Cemental tears may be overlooked, and therefore, they should be included in the differential diagnosis of periapical periodontitis, endodontic‐periodontal lesion and vertical root fracture (VRF).
BACKGROUND:Squeaking after ceramic-on-ceramic total hip arthroplasty is a relatively uncommon phenomenon. It usually does not require treatment in the absence of pain, mechanical symptoms, and/or ...relentless squeaking. The purpose of this investigation was to report on four patients who presented with hip pain and squeaking due to fractured ceramic liners after ceramic-on-ceramic total hip arthroplasty.
METHODS:Four patients with painful squeaking after ceramic-on-ceramic total hip arthroplasty were seen at our institution. One patient had a revision for suspected loosening and excessive anteversion of the cup noted on radiographs and magnetic resonance imaging (MRI). The remaining three patients had a revision for audible squeaking with progressive pain.
RESULTS:Intraoperatively, the ceramic liners of all four patients were fractured.
CONCLUSIONS:Squeaking after ceramic-on-ceramic total hip arthroplasty rarely is a functional issue. However, painful squeaking without notable trauma may indicate fracture of the ceramic liner. Painful squeaking is difficult to evaluate by conventional imaging. When painful squeaking occurs, exploration via surgical revision is recommended in selected patients, as ceramic liner fractures may go unnoticed on radiographs and/or MRI and thus their actual prevalence may be higher than estimated.
LEVEL OF EVIDENCE:Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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