Peter Verdonk

Universitair Ziekenhuis Ghent, Gand, Flanders, Belgium

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Publications (109)289.7 Total impact

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    ABSTRACT: To investigate the biomechanical effect of skeletal knee joint abnormalities, the authors propose to implant pathologically shaped rapid prototyped implants in cadaver knee specimens. This new method was validated by replacing the native trochlea by a replica implant on four cadaver knees with the aid of cadaver-specific guiding instruments. The accuracy of the guiding instruments was assessed by measuring the rotational errors of the cutting planes (on average 3.01° in extension and 1.18° in external/internal rotation). During a squat and open chain simulation, the patella showed small differences in its articulation with the native trochlea and the replica trochlea, which could partially be explained by the rotational errors of the implants. This study concludes that this method is valid to investigate the effect of knee joint abnormalities with a replica implant as a control condition to account for the influence of material properties and rotational errors of the implant.
    Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine 08/2014; 228(8):833-42. · 1.42 Impact Factor
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    ABSTRACT: Meniscus replacement is of clinical benefit, but universal efficacy remains elusive. A greater understanding of the biological activity within implanted allografts or synthetic scaffolds may assist the development of improved surgical strategies.
    International Orthopaedics 07/2014; · 2.32 Impact Factor
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    ABSTRACT: This study presents the prospective two-year clinical and MRI outcome of autologous matrix-induced chondrogenesis (AMIC) for the treatment of patellofemoral cartilage defects in the knee. Ten patients were clinically prospectively evaluated during 2 years. MRI data were analysed based on the original and modified MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) scoring system. A satisfying clinical improvement became apparent during the 24 months of follow-up. The MOCART scoring system revealed a slight tendency to deterioration on MRI between one and 2 years of follow-up. However, the difference was not statistical significant. All cases showed subchondral lamina changes. The formation of intralesional osteophytes was observed in 3 of the 10 patients (30%). In conclusion, AMIC is safe and feasible for the treatment of symptomatic patellofemoral cartilage defects and resulted in a clinical improvement. However, the favourable clinical outcome of the AMIC technique was not confirmed by the MRI findings.
    Acta orthopaedica Belgica 06/2014; 80(2):251-9. · 0.63 Impact Factor
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    ABSTRACT: This study was designed to describe the clinical and radiographical outcome of the HemiCAP(®) resurfacing system as a salvage treatment for a failed index cartilage procedure. Fourteen patients were treated consecutively and clinically prospectively followed for a mean period of 26.1 ± 12.8 months. All patients were previously treated for their cartilage lesion. Radiographical data were analysed based on the Kellgren and Lawrence system. The patients involved in this study demonstrated a gradual clinical improvement in time. However, radiographically significant osteoarthritic changes were observed during the follow-up period. The position of the HemiCAP(®) resurfacing system was adequate in all cases, and no signs of loosening were observed during the follow-up period. The HemiCAP(®) resurfacing system is feasible as a salvage treatment for a failed index cartilage procedure and resulted in a gradual clinical improvement. However, the favourable clinical outcome was not confirmed by the radiographical findings. LEVEL OF EVIDENCE: IV.
    Knee Surgery Sports Traumatology Arthroscopy 04/2014; · 2.68 Impact Factor
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    ABSTRACT: Introduction La méniscectomie latérale est source de douleurs résiduelles et d’arthrose secondaire même lorsque les indications sont clairement sélectionnées. Hypothèse La reconstruction de la perte de substance méniscale par un substitut biodégradable diminue la douleur et améliore la fonction du genou. Patients et méthodes Cette étude multicentrique prospective porte sur 54 patients (37 hommes/17 femmes ; âge moyen : 28 ans [16–50]). Tous les patients présentaient un syndrome douloureux post-méniscectomie latérale partielle. Ils ont été traités par mise en place sous contrôle arthroscopique d’un substitut biodégradable en polyuréthane (Actifit® Orteq). Les résultats cliniques ont été analysés à 6,12 et 24 mois par l’échelle visuelle analogique (EVA), l’International knee documentation committee score (IKDC) et le Knee injury and osteoarthritis outcome score (KOOS). Résultats L’EVA passait de 5,5 en préopératoire à 3,6 à 6 mois, 3,4 à 12 mois et 2,9 à 24 mois. L’IKDC passait de 47,0 en préopératoire à 60,2, 67,0 et 67,0 à 6,12 et 24 mois. Tous les items du score KOOS augmentaient entre le préopératoire et le recul à 2 ans. Discussion Les résultats montrent une amélioration statistiquement et cliniquement significative de la douleur et des scores fonctionnels. (EVA, IKDC, et tous les items du score KOOS à l’exception de l’activité sportive) à 6 mois, et de tous les items à 2 ans. Le substitut Actifit® est sûr et efficace pour traiter les défects partiels du ménisque latéral. Niveau de preuve IV ; étude prospective multicentrique de cohorte.
    Revue de Chirurgie Orthopédique et Traumatologique 01/2014; 100(1):126.
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    ABSTRACT: Objectives In this pilot study we wanted to evaluate the kinematics of a knee implanted with an artificial polycarbonate-urethane meniscus device, designed for medial meniscus replacement. The static kinematic behavior of the implant was compared to the natural medial meniscus of the non-operated knee. A second goal was to evaluate the motion pattern, the radial displacement and the deformation of the meniscal implant. Materials and Methods Three patients with a polycarbonate-urethane implant were included in this prospective study. An open-MRI was used to track the location of the implant during static weight-bearing conditions, within a range of motion of 0° to 120° knee flexion. Knee kinematics were evaluated by measuring the tibiofemoral contact points and femoral roll-back. Meniscus measurements (both natural and artificial) included anterior-posterior meniscal movement, radial displacement, and meniscal height. Results No difference (p > 0.05) was demonstrated in femoral roll-back and tibiofemoral contact points during knee flexion between the implanted and the non-operated knees. Meniscal measurements showed no significant difference in radial displacement and meniscal height (p > 0.05) at all flexion angles, in both the implanted and non-operated knees. A significant difference (p ≤ 0.05) in anterior-posterior movement during flexion was observed between the two groups. Conclusions In this pilot study, the artificial polycarbonate-urethane implant, indicated for medial meniscus replacement, had no influence on femoral roll-back and tibiofemoral contact points, thus suggesting that the joint maintains its static kinematic properties after implantation. Radial displacement and meniscal height were not different, but anterior-posterior movement was slightly different between the implant and the normal meniscus.
    Clinical Biomechanics. 01/2014;
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    ABSTRACT: Background : Post-operative widening of tibial and/or femoral bone tunnels is a common observation after ACL reconstruction, especially with soft-tissue grafts. There are no studies comparing tunnel widening in hamstring autografts versus tibialis anterior allografts. The goal of this study was to observe the difference in tunnel widening after the use of allograft vs. autograft for ACL reconstruction, by measuring it with a novel 3-D computed tomography based method. Methods : Thirty-five ACL-deficient subjects were included, underwent anatomic single-bundle ACL reconstruction and were evaluated at 1 year after surgery with the use of 3-D CT imaging. Three independent observers semi-automatically delineated femoral and tibial tunnel outlines, after which a best-fit cylinder was derived and the tunnel diameter was determined. Finally, intra- and inter-observer reliability of this novel measurement protocol was defined. Results : In femoral tunnels, the intra-observer ICC was 0.973 (95% CI: 0.922-0.991) and the inter-observer ICC was 0.992 (95% CI: 0.982-0.996). In tibial tunnels, the intra-observer ICC was 0.955 (95% CI: 0.875 – 0.985). The combined inter-observer ICC 0.970 (95% CI:). Tunnel widening was significantly higher in allografts compared to autografts, in the tibial tunnels (p = 0.013) as well as in the femoral tunnels (p = 0.007). Conclusions : To our knowledge, this novel, semi-automated 3D-computed tomography image processing method has shown to yield highly reproducible results for the measurement of bone tunnel diameter and area. This series showed a significantly higher amount of tunnel widening observed in the allograft group at 1-year follow-up. Level of Evidence: Level II, Prospective comparative study
    The Knee. 01/2014;
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    ABSTRACT: Segmental tissue loss in the lateral meniscus is associated with pain and increased risk of osteoarthritis even when indications have been carefully considered. Repairing the defect using a novel biodegradable scaffold will reduce pain and restore the knee function. In this prospective multicenter study, a total of 54 patients (37 males/17 females; mean age: 28years [16-50]) were enrolled. All patients presented with postmeniscectomy syndrome and segmental lateral meniscus loss, and were treated with a polyurethane biodegradable scaffold (Actifit(®), Orteq) implanted arthroscopically. Clinical outcomes were assessed at 6, 12 and 24months using Visual Analogue Scale (VAS), International Knee Documentation Committee Score (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS). VAS decreased from 5.5 at baseline to 3.6 at 6months, 3.4 at 12months and 2.9 at 24months. IKDC improved from 47.0 at baseline to 60.2, 67.0 and 67.0 at 6, 12 and 24months. All KOOS subscores improved between baseline and 24months. Clinical results of this study demonstrate clinically and statistically significant improvements of pain and function scores (VAS, IKDC, and all KOOS subscales except sport), at the 6months follow-up and on all clinical outcomes at the 2-year follow-up. The Actifit(®) scaffold is safe and effective in treating lateral meniscus defects. continuous prospective multicenter study.
    Orthopaedics & Traumatology Surgery & Research 12/2013; · 1.06 Impact Factor
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    ABSTRACT: Trochlear dysplasia is known as the primary predisposing factor for patellar dislocation. Current methods to describe trochlear dysplasia are mainly qualitative or based on a limited number of discrete measurements. The purpose of this study is to apply statistical shape analysis to take the full geometrical complexity of trochlear dysplasia into account. Statistical shape analysis was applied to 20 normal and 20 trochlear dysplastic distal femur models, including the cartilage. This study showed that the trochlea was anteriorized, proximalized and lateralized and that the mediolateral width and the notch width were decreased in the trochlear dysplastic femur compared to the normal femur. The first three principal components of the trochlear dysplastic femurs, accounting for 79.7% of the total variation, were size, sulcus angle and notch width. Automated classification of the trochlear dysplastic and normal femora achieved a sensitivity of 85% and a specificity of 95%. This study shows that shape analysis is an outstanding method to visualise the location and magnitude of shape abnormalities. Improvement of automated classification and subtyping within the trochlear dysplastic group are expected when larger training sets are used. Classification of trochlear dysplasia, especially borderline cases may be facilitated by automated classification. Furthermore, the identification of a decreased notch width in association with an increased sulcus angle can also contribute to the diagnosis of trochlear dysplasia.
    The Knee 12/2013; · 2.01 Impact Factor
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    ABSTRACT: The objective of this study was to validate a new technique to safely obtain core biopsy specimens of the anterior cruciate ligament (ACL) without jeopardizing the ACL's biomechanical properties. Eleven pairs of fresh porcine femur-ACL-tibia complexes were tested in a loading frame. The ACL of one knee was biopsied using a spring-loaded core biopsy device, whereas the contralateral ACL was tested as the control. Biomechanical properties of the biopsied and control ACLs were compared. The ultimate load to failure was 1,202 N ± 171.1 N and 1,193 N ± 228.7 N (P = .8984) for biopsied and non-biopsied ACLs, respectively. No significant differences were noted for maximal elongation at failure, maximal strain, absorbed energy, and stiffness between biopsied and non-biopsied ACLs. The results of this study indicate that a new ACL core biopsy technique can be performed while preserving the ligament's structural integrity. The presented core biopsy technique could be regarded as a dedicated tool to elucidate the poorly understood (patho)biological processes occurring in both the native and reconstructed ACLs.
    Arthroscopy The Journal of Arthroscopic and Related Surgery 11/2013; · 3.10 Impact Factor
  • Gregor Vivod, Peter Verdonk, Matej Drobnič
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    ABSTRACT: A retrospective single-centre study was focused on the long-term outcome after different patello-femoral (PF) realignment procedures. Thirty-nine patients treated for recurrent PF instability were examined after a mean post-operative time of 22.5 years. Their 78 knees were divided into: non-operated knees (NON-OPERATED)-N = 24, isolated proximal procedures (PROXIMAL)-N = 22, isolated distal procedures (DISTAL)-N = 10, and combined procedures (COMBINED)-N = 22. PF-related medical history together with clinical, subjective (KOOS and Kujala scores), and radiographic (Caton-Deschamps PF height index, Kellgren-Lawrence scale for tibio-femoral OA, and Iwano classification for PF OA) evaluation was conducted. PF re-dislocation rate was comparable between PROXIMAL (36 %), DISTAL (20 %), and COMBINED (32 %). Isolated proximal procedures revealed less central patella positions (PROXIMAL 64 %; DISTAL 90 %; COMBINED 95 %) and more frequent PF apprehension test (PROXIMAL 82 %; DISTAL 40 %, COMBINED 50 %). KOOS and Kujala scores were similar in all three surgical subgroups, but significantly lower than in NON-OPERATED. Patellas were positioned lower after DISTAL, 0.8 (0.5-1.0) or COMBINED, 0.9 (0.4-1.3). Kellgren-Lawrence scores ≥2 were found in 42 % NON-OPERATED, 37 % PROXIMAL, 70 % DISTAL, and 59 % COMBINED, whereas Iwano classification ≥2 was confirmed in 46 % NON-OPERATED, 64 % PROXIMAL, 80 % DISTAL, and 86 % COMBINED. High PF re-dislocation rates together with a very high incidence of PF OA indicate that PF realignment strategies used traditionally had failed to reach their long-term expectations. The transfer of tibial tuberosity resulted in more constrained PF joints than isolated proximal procedures which allowed for more residual PF instability. Distal procedures additionally increased the likelihood for tibio-femoral OA. LEVEL OF EVIDENCE: III.
    Knee Surgery Sports Traumatology Arthroscopy 09/2013; · 2.68 Impact Factor
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    ABSTRACT: In 1879, the French surgeon Segond described the existence of a 'pearly, resistant, fibrous band' at the anterolateral aspect of the human knee, attached to the eponymous Segond fracture. To date, the enigma surrounding this anatomical structure is reflected in confusing names such as '(mid-third) lateral capsular ligament', 'capsulo-osseous layer of the iliotibial band' or 'anterolateral ligament', and no clear anatomical description has yet been provided. In this study, the presence and characteristics of Segond's 'pearly band', hereafter termed anterolateral ligament (ALL), was investigated in 41 unpaired, human cadaveric knees. The femoral and tibial attachment of the ALL, its course and its relationship with nearby anatomical structures were studied both qualitatively and quantitatively. In all but one of 41 cadaveric knees (97%), the ALL was found as a well-defined ligamentous structure, clearly distinguishable from the anterolateral joint capsule. The origin of the ALL was situated at the prominence of the lateral femoral epicondyle, slightly anterior to the origin of the lateral collateral ligament, although connecting fibers between the two structures were observed. The ALL showed an oblique course to the anterolateral aspect of the proximal tibia, with firm attachments to the lateral meniscus, thus enveloping the inferior lateral geniculate artery and vein. Its insertion on the anterolateral tibia was grossly located midway between Gerdy's tubercle and the tip of the fibular head, definitely separate from the iliotibial band (ITB). The ALL was found to be a distinct ligamentous structure at the anterolateral aspect of the human knee with consistent origin and insertion site features. By providing a detailed anatomical characterization of the ALL, this study clarifies the long-standing enigma surrounding the existence of a ligamentous structure connecting the femur with the anterolateral tibia. Given its structure and anatomic location, the ALL is hypothesized to control internal tibial rotation and thus to affect the pivot shift phenomenon, although further studies are needed to investigate its biomechanical function.
    Journal of Anatomy 08/2013; · 2.36 Impact Factor
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    ABSTRACT: PURPOSE: The authors hypothesise that the trochlear dysplastic distal femur is not only characterised by morphological changes to the trochlea. The purpose of this study is to describe the morphological characteristics of the trochlear dysplastic femur in and outside the trochlear region with a landmark-based 3D analysis. METHODS: Arthro-CT scans of 20 trochlear dysplastic and 20 normal knees were used to generate 3D models including the cartilage. To rule out size differences, a set of landmarks were defined on the distal femur to isotropically scale the 3D models to a standard size. A predefined series of landmark-based reference planes were applied on the distal femur. With these landmarks and reference planes, a series of previously described characteristics associated with trochlear dysplasia as well as a series of morphometric characteristics were measured. RESULTS: For the previously described characteristics, the analysis replicated highly significant differences between trochlear dysplastic and normal knees. Furthermore, the analysis showed that, when knee size is taken into account, the cut-off values of the trochlear bump and depth would be 1 mm larger in the largest knees compared to the smallest knees. For the morphometric characteristics, the analysis revealed that the trochlear dysplastic femur is also characterised by a 10 % smaller intercondylar notch, 6-8 % larger posterior condyles (lateral-medial) in the anteroposterior direction and a 6 % larger medial condyle in the proximodistal direction compared to a normal femur. CONCLUSIONS: This study shows that knee size is important in the application of absolute metric cut-off values and that the posterior femur also shows a significantly different morphology.
    Knee Surgery Sports Traumatology Arthroscopy 06/2013; · 2.68 Impact Factor
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    ABSTRACT: BACKGROUND: In a previous study, we described the distribution of coronal alignment in a normal asymptomatic population and recognized the occurrence of constitutional varus in one of four individuals. It is important to further investigate the influence of this condition on the joint line orientation and how the latter is affected by the onset and progression of arthritis. QUESTIONS/PURPOSES: The purposes of this study are (1) to describe the distribution of joint line orientation in the coronal plane in the normal population; (2) to compare joint line orientation between patients with constitutional varus and neutral mechanical alignment; and (3) to compare joint line orientation between a cohort of patients with prearthritic constitutional varus and a cohort of patients with established symptomatic varus arthritis. METHODS: Full-leg standing hip-to-ankle digital radiographs were performed in 248 young healthy individuals and 532 patients with knee arthritis. Hip-knee-ankle (HKA) angle and tibial joint line angle (TJLA) were measured in the coronal plane. Patients were subdivided into varus (HKA ≤ -3°), neutral, and valgus (HKA ≥ 3°). RESULTS: The mean TJLA in healthy subjects was 0.3° (SD 2.0°). TJLA was parallel to the floor in healthy subgroups with neutral alignment (TJLA 0.3°, SD 1.9) and constitutional varus (TJLA 0.2°, SD 2.2°). In patients with symptomatic arthritis and varus alignment, the TJLA opened medially (mean -1.9°, SD 3.5°). CONCLUSIONS: Constitutional varus does not affect joint line orientation. Advanced medial arthritis causes divergence of the joint line from parallel to the floor. These findings influence decision-making for osteotomy and alignment in total knee arthroplasty. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
    Clinical Orthopaedics and Related Research 06/2013; · 2.79 Impact Factor
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    Ans Van Ginckel, Peter Verdonk, Erik Witvrouw
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    ABSTRACT: OBJECTIVE: To summarize the current evidence of MRI-measured cartilage adaptions following ACL reconstruction and of the potential factors that might influence these changes, including the effect of treatment on the course of cartilage change (i.e., surgical versus non-surgical treatment). METHODS: A literature search was conducted in 7 electronic databases extracting 12 full-text articles. These articles reported on in vivo MRI-related cartilage longitudinal follow-up after ACL injury and reconstruction in "young" adults. Eligibility and methodological quality was rated by 2 independent reviewers. A best-evidence synthesis was performed for reported factors influencing cartilage changes. RESULTS: Methodological quality was heterogeneous amongst articles (i.e., score range:31.6-78.9%). Macroscopic changes were detectable as from 2 years follow-up next to or preceded by ultra-structural and functional (i.e., contact-deformation) changes, both in the lateral and medial compartment. Moderate-to-strong evidence was presented for meniscal lesion or meniscectomy, presence of bone marrow lesions, time from injury, and persisting altered biomechanics, possibly affecting cartilage change after ACL reconstruction. First-year morphological change was more aggravated in ACL reconstruction compared to non-surgical treatment. CONCLUSION: In view of OA prevention after ACL reconstruction, careful attention should be paid to the rehabilitation process and to the decision on when to allow return to sports. These decisions should also consider cartilage fragility and functional adaptations after surgery. In this respect, the first years following surgery are of paramount importance for prevention or treatment strategies that aim at impediment of further matrix deterioration. Considering the low number of studies and the methodological caveats, more research is needed.
    Osteoarthritis and Cartilage 05/2013; · 4.26 Impact Factor
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    ABSTRACT: PURPOSE: Ingrowth of meniscal tissue into a meniscal scaffold can be optimized by securely fixing the scaffold into the meniscal remnants. The purpose of this research was to test and compare commonly used suture types and suture materials to fix a meniscal scaffold. METHODS: Forty fresh porcine menisci were used. All tests used the same polyurethane-based scaffold. The load to failure of horizontal, vertical and diagonal sutures with PDS 0 and with Ethibond 0, and diagonal sutures with Ultra Fast-Fix(®) and Sequent(®) to fix a meniscal scaffold were tested. Five tests were conducted for each configuration. RESULTS: All constructs failed in the scaffold at a mean pullout force of 50.6 N (SD 12.7). Inferior results were noted for vertical sutures (40.1 N, SD 6.3) compared to horizontal (49.8 N, SD 5.5, p = 0.0007) and diagonal (51.7 N, SD 15.6, p = 0.024) sutures and for Ethibond 0 (41.4 N, SD 6.2) compared to PDS 0 (51.3 N, SD 12.9, p = 0.001). When comparing the diagonal suture placements, only Ethibond 0 (42.9 N, SD 5.4) showed significantly inferior results compared to PDS 0 (60.1 N, SD 16.9, p = 0.03), Ultra Fast-Fix(®) (60.1 N, SD 9.3, p = 0.004) and Sequent(®) (65.8 N, SD 4.4, p < 0.0001). CONCLUSIONS: The most common failure mode when fixing a polyurethane-based meniscal scaffold is suture pull-through of the scaffold in the distraction mode. This happens at a rather low pullout force and might preclude the use of this scaffold clinically. Vertical sutures and Ethibond 0 multifilament braided sutures fail at lower forces, and the tested commercial devices show promising results.
    Knee Surgery Sports Traumatology Arthroscopy 04/2013; · 2.68 Impact Factor
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    ABSTRACT: In this imaging study, the radial displacement of meniscal allograft transplants (MATs), inserted with 2 different techniques, namely open soft-tissue fixation and arthroscopic bone tunnel fixation, was compared 1 year postoperatively. In this study, 37 patients received MATs: 16 MATs (10 lateral and 6 medial) were inserted by an open soft-tissue technique (open MATs), whereas 21 MATs (14 lateral and 7 medial) were implanted by an arthroscopic bone tunnel procedure (arthroscopic MATs). Radial displacement, in millimeters, was evaluated 1 year postoperatively on 1.5-T magnetic resonance images. The number of MATs with radial displacement larger or smaller than 3 mm was determined. To compare radial displacement of open versus arthroscopic MATs, the Mann-Whitney U test was used. The radial displacement of open lateral and medial MATs was significantly larger (all reported P < .02) than that of arthros-copic MATs. In all cases, both open and arthroscopic, the radial displacement of MATs was significantly larger (all reported P < .007) than that of normal menisci. Radial displacement of less than 3 mm was found in 0 of 6 patients with open medial MATs versus 6 of 7 patients with arthroscopic MATs and was found in 1 of 10 patients with open lateral MATs versus 4 of 14 patients with arthroscopic MATs. The radial displacement of MATs arthroscopically inserted with bone tunnel fixation is significantly less than the radial displacement of MATs inserted with open soft-tissue fixation. In addition, normal menisci displace significantly less than meniscal allografts. The clinical importance of radial displacement remains to be determined. Level III, retrospective comparative study.
    Arthroscopy The Journal of Arthroscopic and Related Surgery 03/2013; 29(3):514-21. · 3.10 Impact Factor
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    ABSTRACT: This article presents a pilot study on a quasi-static knee rig designed to investigate the influence of pathologies and surgical interventions on the patellofemoral kinetics of cadaveric knees. The knee rig allows cadaveric knees to flex and extend under a simulated body weight by transmitting a force to the quadriceps tendon. During the squat simulation, the ground reaction force stays within physiological values. Before using this device to answer clinical questions, two knee specimens were tested to assess the repeatability of the rig. Four repeated flexion-extension cycles were performed under a simulated body weight of 700 N, with an isolated force on the quadriceps tendon up to 2700 N and with a ground reaction force close to 350 N. The resulting patellofemoral contact area shifted from distal to proximal during knee flexion. From 20 degrees to 60 degrees of knee flexion, the mean contact area and pressure increased from 80.2 +/- 3.3 to 349.5 +/- 10.1 mm2 and from 0.9 +/- 0.2 to 5.9 +/- 0.7 MPa, respectively. The transmitted force on the quadriceps tendon, the ground reaction force and the patellofemoral contact area and pressure were continuously measured and showed a relative variability of 1.6%, 2.4%, 2.8% and 3.2%, respectively. The presented knee rig shows a good repeatability that allows us to use this knee rig to quantify the influence of anatomical changes on the patellofemoral contact area and pressures during a squat simulation.
    Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine 03/2013; 227(3):229-33. · 1.42 Impact Factor
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    Asbjørn Arøen, Peter Verdonk
    Knee Surgery Sports Traumatology Arthroscopy 02/2013; · 2.68 Impact Factor
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    ABSTRACT: PURPOSE: The primary aim is to document objective and subjective clinical outcome after knee arthroplasty for failed meniscal allograft transplantation; secondly, to investigate the influence of previous meniscal allograft surgery on the clinical outcome after a knee arthroplasty procedure; thirdly, to identify possible prognostic factors for the failure of meniscal allograft, such as potential number of concomitant procedures or pre-transplantation HSS-scores. The study population was compared to a control group of primary total knee arthroplasties. METHODS: The pre-operative phase, prior to meniscal allograft transplantation, was evaluated by the HSS questionnaire. At final follow-up, the clinical outcome was evaluated by the HSS, KOOS and SF-36 questionnaires. The mean follow-up was 16 years and 2 months. The control group, matched for age and sex, comprised patients with primary total knee arthroplasty. RESULTS: Statistical analysis showed that for the HSS-scores, there was no significant difference between the study population and the control group. KOOS data showed that the control group scored better overall. There was no significant difference between the HSS-scores after the transplantation and after the knee prosthesis. However, both showed a significant improvement regarding the clinical condition before meniscal transplantation. CONCLUSIONS: The clinical results after revised meniscal transplantation by means of knee prosthesis are highly variable with a tendency to have a lower score than patients with a primary knee prosthesis. Patients who underwent a revision of their meniscal allograft transplantation by means of a knee arthroplasty still had a significant better clinical outcome than prior to the meniscal allograft transplantation. There were no prognostic factors found by which one can determine whether a meniscal allograft will have a good survival or not. LEVEL OF EVIDENCE: IV.
    Knee Surgery Sports Traumatology Arthroscopy 02/2013; · 2.68 Impact Factor

Publication Stats

1k Citations
289.70 Total Impact Points


  • 2004–2014
    • Universitair Ziekenhuis Ghent
      • Department of Rheumatology
      Gand, Flanders, Belgium
  • 2013
    • University of Oslo
      Kristiania (historical), Oslo County, Norway
    • Fonds Wetenschappelijk Onderzoek
      Bruxelles, Brussels Capital Region, Belgium
  • 2011–2013
    • Universitair Ziekenhuis Leuven
      • Department of Orthopaedic surgery
      Louvain, Flanders, Belgium
    • Zagazig University
      • Faculty of Medicine
      Az Zaqāzīq, Eastern Province, Egypt
  • 2003–2013
    • Ghent University
      • • Department of Rehabilitation Sciences and Physiotherapy
      • • Rheumatology
      • • Faculty of Medicine and Health Sciences
      • • Department of Textiles
      Gand, Flanders, Belgium
  • 2012
    • AZ Sint-Lucas Brugge
      Bruges, Flanders, Belgium
  • 2010
    • University of Angers
      Angers, Pays de la Loire, France
  • 2007–2009
    • Hospices Civils de Lyon
      Lyons, Rhône-Alpes, France
    • Centre Hospitalier Universitaire de Lyon
      Lyons, Rhône-Alpes, France