Johan Bellemans - Academia.edu (original) (raw)

Papers by Johan Bellemans

Acta orthopaedica Belgica, 2013

In an epidemiological study we assessed the evolution in the incidence and possible risk factors ... more In an epidemiological study we assessed the evolution in the incidence and possible risk factors of knee injuries, especially anterior cruciate ligament (ACL) injuries, in Belgian soccer over one decade. Two soccer seasons (1999-2000 and 2009-2010) were compared and 56,364 injury reports registered by the KBVB-URBSFA were retrieved. Knee injuries totaled 9.971 cases, 5.495 in the first season (1999-2000) and 4.476 in the second (2009-2010): a significant decrease in incidence from 1.5 per 100 players in 2000 to 1.2 knee injuries in 2010. Six percent of all knee injuries were ACL injuries. The reported incidence of ACL tears slightly increased from 0.081 to 0.084 per 100 players. Female gender, competition and age over 18 years were prognosticators for ACL injuries. Enhanced prevention programs for ACL injuries, especially in those sports groups are warranted.

Acta orthopaedica Belgica, 2013

An association between lateral patellar dislocation (LPD) and medial collateral ligament injury (... more An association between lateral patellar dislocation (LPD) and medial collateral ligament injury (MCL) has recently been demonstrated on MRI. The same valgus injury that disrupts the femoral MCL insertion can also cause a simultaneous MPFL tear at its femoral insertion, due to the close anatomical relationship of both ligamentous structures. Valgus laxity due to MCL-deficiency increases the Q-angle and further adversely affects patellar stability. A knee diagnosed with a severe MCL tear, should be evaluated for patellofemoral instability, as a temporary patella dislocation could have been caused by the same injury and an acute LPD indicating a tear of the MPFL can be associated with a concomitant injury of the MCL. In case of recurrent symptoms of patellofemoral instability in a MCL-deficient knee, both the MPFL and MCL should be managed operatively. An isolated MPFL reconstruction in this knee is likely to fail due to a persistent increase of the Q-angle.

Acta orthopaedica Belgica, 2013

Patient dissatisfaction after TKA has not been improved dramatically since the introduction of ne... more Patient dissatisfaction after TKA has not been improved dramatically since the introduction of new alignment (navigation, custom guides) and balancing techniques. Orthopaedic surgeons consider the ligaments as essentially passive stabilizing structures. However, during the activities of daily living, the joints are stabilized primarily by our muscle actions that both move and stabilize the joints. Isometric motion of the joint does not cause the distance separating the bone attachments to change. The practical importance of isometry is confirmed by the fact that ligaments are elongated irreversibly if the strain exceeds a given level (5%). In ligament surgery as well as in TKA, the concept of isometry is highly important. In this paper we wish to highlight the fact that the role of the soft tissue envelope goes beyond structural and mechanical support. The presence of mechano- and nocireceptors in the structures around the human knee joint has long been reported but is underrecognis...

Acta orthopaedica Belgica, 2011

We compared the 3 to 5 year clinical and radiological results of two different hybrid metal-on-me... more We compared the 3 to 5 year clinical and radiological results of two different hybrid metal-on-metal resurfacing hip arthroplasty designs in 28 patients who had undergone bilateral hip resurfacing with ReCap implants on one side and BHR implants on the other side. Both hips were compared in each patient, to specifically evaluate the bone response to the cemented femoral component. Post operative function was measured with the Harris Hip Score and University of California at Los Angeles (UCLA) Activity Score, and was excellent in these patients. Mean cup inclination was 43.3 degrees +/- 7 degrees (43.3 degrees +/- 7 degrees for the BHR and 43.4 +/- 6 degrees for the Recap). The inclination angle was greater than 45 degrees in 15 patients: 7 with a BHR, 8 with a Recap; eight patients showed inclination angles greater than 50 degrees (4 patients in each group). All acetabular monoblock cups were well fixed. One patient (1.8%) had radiographs showing bone changes of uncertain significan...

Acta orthopaedica Belgica, 2010

Polyethylene (PE) wear is the limiting factor for the longevity of a conventional total knee arth... more Polyethylene (PE) wear is the limiting factor for the longevity of a conventional total knee arthroplasty (TKA). Excessive wear leads to loosening and eventual implant failure. The aim of our in vitro study was to investigate wear of a PE tibial insert on a rotating platform as compared to the same insert fixed to the tibial baseplate and articulating with a similar femoral component. All tests were performed at Endolab Laboratories, Rosenheim, Germany using a knee joint simulator following ISO 14243-1. Three specific configurations were tested and compared to a loaded soak control: (1) the rotating platform using machined polyethylene (PE), (2) fixed bearing using machined PE, (3) fixed bearing using compression-moulded PE. Calf serum with a high protein concentration of 30 g/l was chosen as test lubricant. PE wear was measured gravimetrically using the ISO 14243-2 protocol. The total wear rates found for all systems tested were low. The mean wear rate was 1.40 mg per million cycle...

Knee Surgery, Sports Traumatology, Arthroscopy, 2014

Although controversy still remains, isolated patellofemoral arthroplasty recently gained in popul... more Although controversy still remains, isolated patellofemoral arthroplasty recently gained in popularity as a treatment option for patellofemoral osteoarthritis. It has compared to total knee arthroplasty the advantage of preserving the tibiofemoral articulation, which in theory would allow the preservation of natural tibiofemoral kinematics. Today, however, no data exist to support this assumption. This study was therefore performed in order to investigate the effect of isolated patellofemoral arthroplasty on the native three-dimensional tibiofemoral kinematic behaviour and whether a change in patellar thickness would have an influence.

Acta orthopaedica Belgica, 2005

The goal of reducing the length of a patient's hospital stay after orthopaedic surgery has re... more The goal of reducing the length of a patient's hospital stay after orthopaedic surgery has recently gained much interest from surgeons and hospital administrators. The influence of hospital stay reduction on qualitative outcome is not always documented. The purpose of this study was to investigate this relationship in more detail. We report our experience with patients undergoing total knee arthroplasty. In 2000, an in-hospital clinical pathway for patients undergoing total knee arthroplasty was instituted at the University Hospitals Pellenberg, Belgium. We evaluated this pathway in 103 patients by using a pre-experimental, interrupted, time-series design. This pathway significantly decreased length of stay by 33% without negatively affecting functional outcomes during hospitalisation. In further research also the long-term effects have to be studied.

British journal of sports medicine

Deficits in neuromuscular control are believed to increase re-injury risk after anterior cruciate... more Deficits in neuromuscular control are believed to increase re-injury risk after anterior cruciate ligament reconstruction (ACLR). Previous studies mainly focused on muscles at the operated knee, less on muscles around other joints of the operated and non-operated leg. To evaluate lower extremity muscle onset times during the transition from double-leg stance to single-leg stance in ACLR and non-injured control subjects. Cross-sectional (retrospective). Controlled laboratory study. 20 ACLR subjects (15 females, 5 males), 23.1±13.9 months after ACLR and fully returned to their pre-injury sport, and 20 non-injured control subjects (15 females, 5 males) participated in the study. Both groups were matched for age, gender, weight, height and activity level. All ACL injuries were caused by a non-contact injury mechanism. A transition task from double-leg stance to single-leg stance with eyes closed was performed, using a single force plate and surface electromyography. Movement speed was s...

British journal of sports medicine

Despite recent advances in rehabilitation and secondary prevention strategies after anterior cruc... more Despite recent advances in rehabilitation and secondary prevention strategies after anterior cruciate ligament reconstruction (ACLR), re-injury rates remain high and long-term outcomes are often disappointing. Deficits in postural stability are shown to be important. To evaluate postural stability during the transition from double-leg stance to single-leg stance in ACLR and non-injured control subjects. Cross-sectional (retrospective). Controlled laboratory study. 20 ACLR subjects (15 females, 5 males), 23.1±13.9 months after ACLR and fully returned to their pre-injury sport, and 20 non-injured control subjects (15 females, 5 males) participated in the study. Both groups were matched for age, gender, weight, height and activity level. All ACL injuries were caused by a non-contact injury mechanism. A transition task from double-leg stance to single-leg stance with eyes closed was performed while standing on a single force plate. Movement speed was standardized. Both legs of each subj...

The Knee, 2014

Background: Post-operative widening of tibial and/or femoral bone tunnels is a common observation... more 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 one 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 was 0.970 (95% CI: 0.987-0.917). 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 one-year follow-up. Level of evidence: Level II, Prospective comparative study.

Hip International, 2011

ABSTRACT No abstract.

Clinical biomechanics (Bristol, Avon), Jan 17, 2015

An anterior cruciate ligament injury may lead to deteriorations in postural stability. The goal o... more An anterior cruciate ligament injury may lead to deteriorations in postural stability. The goal of this study was to evaluate postural stability during the transition from double-leg stance to single-leg stance of both legs in anterior cruciate ligament injured subjects and non-injured control subjects with a standardized methodology. Fifteen control subjects and 15 anterior cruciate ligament injured subjects (time after injury: mean (SD)=1.4 (0.7) months) participated in the study. Both groups were similar for age, gender, height, weight and body mass index. Spatiotemporal center of pressure outcomes of both legs of each subject were measured during the transition from double-leg stance to single-leg stance in eyes open and eyes closed conditions. Movement speed was standardized. The center of pressure displacement after a new stability point was reached during the single-leg stance phase was significantly increased in the anterior cruciate ligament injured group compared to the co...

Virchows Archiv, 1998

Synovial chondromatosis is a rare lesion, which is still believed by most authors to be reactive ... more Synovial chondromatosis is a rare lesion, which is still believed by most authors to be reactive rather than neoplastic. We report on a case of synovial chondromatosis with clonal chromosomal changes [43,XX,der (1) t (1;13) (p21-22;q21),-6,-13,-14, add(21) (q21)]. The presence of clonal chromosomal changes in this and in three previously reported cases suggests that synovial chondromatosis is a true neoplastic lesion.

Scandinavian Journal of Medicine and Science in Sports, 2002

The goal of this prospective study was to determine the outcome-predictive role of various parame... more The goal of this prospective study was to determine the outcome-predictive role of various parameters in the nonoperative treatment of chronic anterior knee pain patients. Thirty patients followed a five-week treatment program, which consisted out of only closed kinetic chain exercises. Prior to this treatment all subjects were evaluated on muscular characteristics, subjective symptoms, weight, sex, duration of symptoms and functional performance. A multiple stepwise regression analysis revealed that the reflex response time of m. vastus medialis obliquus (VMO) (P=0.041; 0.026), and the duration of symptoms (P=0.019; 0.045) were the only two parameters which were significantly associated with the outcome (evaluated by the Kujala score) at five weeks, and at three months. The shorter the duration of symptoms, or the faster the reflex response time of VMO prior to the treatment, the better the outcome after a closed kinetic chain exercise program. The statistical significance of these parameters in this study may be seen as an indication of the importance of these variables as predictors of the outcome of a closed kinetic chain strengthening program. Using this information, it seems clinically important to begin the treatment program before the anterior knee pain becomes more chronic and treatment results become less good.

Scandinavian Journal of Medicine and Science in Sports, 2003

The purpose of this prospective randomized intervention study was to evaluate the effect of two e... more The purpose of this prospective randomized intervention study was to evaluate the effect of two exercise protocols on reflex response time of vastus medialis obliquus (VMO), vastus lateralis (VL), in patients with anterior knee pain. Sixty patients were randomized into a 5-week treatment program, which consisted of only open kinetic chain tonification exercises (group I) (n = 30), or only closed kinetic chain tonification exercises (group II) (n = 30). Assessment of an aspect of neuromotor control was obtained by measuring the reflex response times of VMO and VL at the time of initial clinical examination, at the end of the exercise period (five weeks), and three months after the completion of the exercise period. At these evaluation occasions, the intensity and the number of times that the patients experienced anterior knee pain during daily life was recorded on a Visual Analog Scale (VAS). No alterations in reflex response times of VMO and VL were observed in either group. Changes of anterior knee pain over time were statistically significant in both groups. Only small and not statistically supported differences in anterior knee pain were found between the two groups. These results suggest that the reflex response times of the two vasti muscles can not be altered after a five week open or closed kinetic chain exercise program. In contrast, knee pain decreased significantly in both groups.

Physiotherapy Theory and Practice, 2011

The major aim of the study was (1) to compare the physiotherapy management in patients treated wi... more The major aim of the study was (1) to compare the physiotherapy management in patients treated with autologous chondrocyte implantation (ACI) versus microfracture (MF) at the knee using a standardized rehabilitation protocol; and (2) to investigate the effect of activities in low-load conditions after surgery on the functional recovery was explored. 95 physiotherapists received a standardized rehabilitation protocol that was used in a randomized controlled trial. A secondary analysis on patients' outcome was studied in a cohort design. An electronic report form including 18 physiotherapy variables was used to compare physiotherapy management. Patients' functional outcome was assessed using the KOOS (Knee Injury Osteoarthritis Outcome Score) and the pooled symmetry index (SI) based on one strength and three hop tests. Both subjective and objective outcomes were evaluated pre-surgery, and at 1 and 2 years post-surgery. 65 physiotherapists adhered very consistently to the protocol during the first 3 months and showed a similar preference and timing for the physiotherapy modalities in both treatment groups. Patients with high amount of low-load activities (LLA+, n=21) post-surgery performed significantly better compared to patients with low amount of LLA (LLA-, n=17). At 24 months the mean pooled SI of LLA+ cohort was 92.4 compared to 78.2 for LLA- cohort (95% confidence interval [CI] 1.8 to 26.2). Overall, the compliance post-surgery with the rehabilitation protocol was excellent and the applied rehabilitation was comparable in both treatment groups. A high amount of low-load activities post-surgery appears beneficial for the objective functional outcome.

Osteoarthritis and Cartilage, 2007

Osteoarthritis and Cartilage, 2007

Purpose: The aim of work was to analyze clinical effectiveness of fresh bone marrow and periosteu... more Purpose: The aim of work was to analyze clinical effectiveness of fresh bone marrow and periosteum versus autologous chondrocytes in treatment of traumatic and degenerative cartilage defects. Methods and Materials: There were 30 patients involved into this study, with mean age of 37 years. Patients were randomly operated either with chondrocytes or fresh bone marrow. Bone marrow was aspirated from iliac crest and implanted under the periosteum sutured over the defect. Chondrocytes were isolated, cultured, than implanted under collagen membrane. Patients followed same rehabilitation protocol. At 12, 24 and 36 months postoperatively, patients were evaluated with analogue pain scale, Brittberg-Peterson VAS score, Lysholm and IKDC questionnaires. Patients were evaluated with MRI 3 and 12 and 24 months postoperatively. In 3 patients of each group tissue samples were obtained for histological assessment. Results: After 36 months, 12 patients treated with bone marrow were Purpose: It may be expected that a two-step open surgery with characterized chondrocyte implantation (CCI) would be disadvantageous to the pace of knee function recovery compared to a one-step arthroscopic microfracture procedure. The objective was to assess the index knee function in patients following an identical, standardized rehab protocol, as part of a prospective randomized clinical trial comparing CCI to microfracture in treating symptomatic cartilage defects of the knee. Methods and Materials: CCI (N=51) and microfracture (N=61) patients were assessed preoperatively and at 6, 9, and 12 months post operatively. Mobility (AROM), Anterior Laxity (with KT1000), Isokinetic Strength (by peak torque at 60°) and Functionality (with a single hop, the crossover triple hop and timed hop test) were evaluated. Of 112 evaluable patients, 100 completed the mobility tests, 85 the functional tests, 75 the strength tests and 65 of the patients completed the anterior laxity tests. Completion rate was equally divided among both groups. Results: both treatment groups preoperatively. Also at 6, 9 and 12 months no four tests, except at 9 months the difference for quadriceps strength for the microfracture group (Med =186) compared to the CCI group (Med= 144) was

Knee Surgery, Sports Traumatology, Arthroscopy, 2011

Implant registries have been effective in detecting poorly performing implants and surgical strat... more Implant registries have been effective in detecting poorly performing implants and surgical strategies. They learn us however little about many variables that may be equally important to the final result. Today, no standards of care exist for performing total knee arthroplasties (TKA), and little is known about the variability that exists amongst surgeons performing this procedure. A questionnaire with 39 aspects regarding standard surgical routine during TKA was sent to all 112 members of the Belgian Knee Society. Surgeons were stratified according to surgical experience and surgical volume. An important number of routines were performed as standard by the majority (>70%) of surgeons. Surgeons however significantly differed in the following aspects of the procedure: radiographic evaluation, use of minimally invasive surgery (MIS), preferred landmark for femoral component rotation, method of closure and activities allowed postoperatively. Both surgical experience and surgical volume had a significant effect, but their influence on strategies was different. Less-experienced surgeons used the posterior condylar line as their reference for femoral component rotation significantly more frequent than more-experienced surgeons and were more aggressive towards postoperative sports activities compared to more-experienced surgeons. High-volume surgeons used significantly more frequent MIS and low-volume surgeons preferred a more extensive postoperative radiographic evaluation. Data of this study show that an important number of routines are performed similarly by the majority of surgeons, and that minor but significant differences exist between high-volume versus low-volume surgeons, and between experienced versus less-experienced surgeons. Case series, Level IV.

Acta orthopaedica Belgica, 2013

In an epidemiological study we assessed the evolution in the incidence and possible risk factors ... more In an epidemiological study we assessed the evolution in the incidence and possible risk factors of knee injuries, especially anterior cruciate ligament (ACL) injuries, in Belgian soccer over one decade. Two soccer seasons (1999-2000 and 2009-2010) were compared and 56,364 injury reports registered by the KBVB-URBSFA were retrieved. Knee injuries totaled 9.971 cases, 5.495 in the first season (1999-2000) and 4.476 in the second (2009-2010): a significant decrease in incidence from 1.5 per 100 players in 2000 to 1.2 knee injuries in 2010. Six percent of all knee injuries were ACL injuries. The reported incidence of ACL tears slightly increased from 0.081 to 0.084 per 100 players. Female gender, competition and age over 18 years were prognosticators for ACL injuries. Enhanced prevention programs for ACL injuries, especially in those sports groups are warranted.

Acta orthopaedica Belgica, 2013

An association between lateral patellar dislocation (LPD) and medial collateral ligament injury (... more An association between lateral patellar dislocation (LPD) and medial collateral ligament injury (MCL) has recently been demonstrated on MRI. The same valgus injury that disrupts the femoral MCL insertion can also cause a simultaneous MPFL tear at its femoral insertion, due to the close anatomical relationship of both ligamentous structures. Valgus laxity due to MCL-deficiency increases the Q-angle and further adversely affects patellar stability. A knee diagnosed with a severe MCL tear, should be evaluated for patellofemoral instability, as a temporary patella dislocation could have been caused by the same injury and an acute LPD indicating a tear of the MPFL can be associated with a concomitant injury of the MCL. In case of recurrent symptoms of patellofemoral instability in a MCL-deficient knee, both the MPFL and MCL should be managed operatively. An isolated MPFL reconstruction in this knee is likely to fail due to a persistent increase of the Q-angle.

Acta orthopaedica Belgica, 2013

Patient dissatisfaction after TKA has not been improved dramatically since the introduction of ne... more Patient dissatisfaction after TKA has not been improved dramatically since the introduction of new alignment (navigation, custom guides) and balancing techniques. Orthopaedic surgeons consider the ligaments as essentially passive stabilizing structures. However, during the activities of daily living, the joints are stabilized primarily by our muscle actions that both move and stabilize the joints. Isometric motion of the joint does not cause the distance separating the bone attachments to change. The practical importance of isometry is confirmed by the fact that ligaments are elongated irreversibly if the strain exceeds a given level (5%). In ligament surgery as well as in TKA, the concept of isometry is highly important. In this paper we wish to highlight the fact that the role of the soft tissue envelope goes beyond structural and mechanical support. The presence of mechano- and nocireceptors in the structures around the human knee joint has long been reported but is underrecognis...

Acta orthopaedica Belgica, 2011

We compared the 3 to 5 year clinical and radiological results of two different hybrid metal-on-me... more We compared the 3 to 5 year clinical and radiological results of two different hybrid metal-on-metal resurfacing hip arthroplasty designs in 28 patients who had undergone bilateral hip resurfacing with ReCap implants on one side and BHR implants on the other side. Both hips were compared in each patient, to specifically evaluate the bone response to the cemented femoral component. Post operative function was measured with the Harris Hip Score and University of California at Los Angeles (UCLA) Activity Score, and was excellent in these patients. Mean cup inclination was 43.3 degrees +/- 7 degrees (43.3 degrees +/- 7 degrees for the BHR and 43.4 +/- 6 degrees for the Recap). The inclination angle was greater than 45 degrees in 15 patients: 7 with a BHR, 8 with a Recap; eight patients showed inclination angles greater than 50 degrees (4 patients in each group). All acetabular monoblock cups were well fixed. One patient (1.8%) had radiographs showing bone changes of uncertain significan...

Acta orthopaedica Belgica, 2010

Polyethylene (PE) wear is the limiting factor for the longevity of a conventional total knee arth... more Polyethylene (PE) wear is the limiting factor for the longevity of a conventional total knee arthroplasty (TKA). Excessive wear leads to loosening and eventual implant failure. The aim of our in vitro study was to investigate wear of a PE tibial insert on a rotating platform as compared to the same insert fixed to the tibial baseplate and articulating with a similar femoral component. All tests were performed at Endolab Laboratories, Rosenheim, Germany using a knee joint simulator following ISO 14243-1. Three specific configurations were tested and compared to a loaded soak control: (1) the rotating platform using machined polyethylene (PE), (2) fixed bearing using machined PE, (3) fixed bearing using compression-moulded PE. Calf serum with a high protein concentration of 30 g/l was chosen as test lubricant. PE wear was measured gravimetrically using the ISO 14243-2 protocol. The total wear rates found for all systems tested were low. The mean wear rate was 1.40 mg per million cycle...

Knee Surgery, Sports Traumatology, Arthroscopy, 2014

Although controversy still remains, isolated patellofemoral arthroplasty recently gained in popul... more Although controversy still remains, isolated patellofemoral arthroplasty recently gained in popularity as a treatment option for patellofemoral osteoarthritis. It has compared to total knee arthroplasty the advantage of preserving the tibiofemoral articulation, which in theory would allow the preservation of natural tibiofemoral kinematics. Today, however, no data exist to support this assumption. This study was therefore performed in order to investigate the effect of isolated patellofemoral arthroplasty on the native three-dimensional tibiofemoral kinematic behaviour and whether a change in patellar thickness would have an influence.

Acta orthopaedica Belgica, 2005

The goal of reducing the length of a patient's hospital stay after orthopaedic surgery has re... more The goal of reducing the length of a patient's hospital stay after orthopaedic surgery has recently gained much interest from surgeons and hospital administrators. The influence of hospital stay reduction on qualitative outcome is not always documented. The purpose of this study was to investigate this relationship in more detail. We report our experience with patients undergoing total knee arthroplasty. In 2000, an in-hospital clinical pathway for patients undergoing total knee arthroplasty was instituted at the University Hospitals Pellenberg, Belgium. We evaluated this pathway in 103 patients by using a pre-experimental, interrupted, time-series design. This pathway significantly decreased length of stay by 33% without negatively affecting functional outcomes during hospitalisation. In further research also the long-term effects have to be studied.

British journal of sports medicine

Deficits in neuromuscular control are believed to increase re-injury risk after anterior cruciate... more Deficits in neuromuscular control are believed to increase re-injury risk after anterior cruciate ligament reconstruction (ACLR). Previous studies mainly focused on muscles at the operated knee, less on muscles around other joints of the operated and non-operated leg. To evaluate lower extremity muscle onset times during the transition from double-leg stance to single-leg stance in ACLR and non-injured control subjects. Cross-sectional (retrospective). Controlled laboratory study. 20 ACLR subjects (15 females, 5 males), 23.1±13.9 months after ACLR and fully returned to their pre-injury sport, and 20 non-injured control subjects (15 females, 5 males) participated in the study. Both groups were matched for age, gender, weight, height and activity level. All ACL injuries were caused by a non-contact injury mechanism. A transition task from double-leg stance to single-leg stance with eyes closed was performed, using a single force plate and surface electromyography. Movement speed was s...

British journal of sports medicine

Despite recent advances in rehabilitation and secondary prevention strategies after anterior cruc... more Despite recent advances in rehabilitation and secondary prevention strategies after anterior cruciate ligament reconstruction (ACLR), re-injury rates remain high and long-term outcomes are often disappointing. Deficits in postural stability are shown to be important. To evaluate postural stability during the transition from double-leg stance to single-leg stance in ACLR and non-injured control subjects. Cross-sectional (retrospective). Controlled laboratory study. 20 ACLR subjects (15 females, 5 males), 23.1±13.9 months after ACLR and fully returned to their pre-injury sport, and 20 non-injured control subjects (15 females, 5 males) participated in the study. Both groups were matched for age, gender, weight, height and activity level. All ACL injuries were caused by a non-contact injury mechanism. A transition task from double-leg stance to single-leg stance with eyes closed was performed while standing on a single force plate. Movement speed was standardized. Both legs of each subj...

The Knee, 2014

Background: Post-operative widening of tibial and/or femoral bone tunnels is a common observation... more 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 one 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 was 0.970 (95% CI: 0.987-0.917). 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 one-year follow-up. Level of evidence: Level II, Prospective comparative study.

Hip International, 2011

ABSTRACT No abstract.

Clinical biomechanics (Bristol, Avon), Jan 17, 2015

An anterior cruciate ligament injury may lead to deteriorations in postural stability. The goal o... more An anterior cruciate ligament injury may lead to deteriorations in postural stability. The goal of this study was to evaluate postural stability during the transition from double-leg stance to single-leg stance of both legs in anterior cruciate ligament injured subjects and non-injured control subjects with a standardized methodology. Fifteen control subjects and 15 anterior cruciate ligament injured subjects (time after injury: mean (SD)=1.4 (0.7) months) participated in the study. Both groups were similar for age, gender, height, weight and body mass index. Spatiotemporal center of pressure outcomes of both legs of each subject were measured during the transition from double-leg stance to single-leg stance in eyes open and eyes closed conditions. Movement speed was standardized. The center of pressure displacement after a new stability point was reached during the single-leg stance phase was significantly increased in the anterior cruciate ligament injured group compared to the co...

Virchows Archiv, 1998

Synovial chondromatosis is a rare lesion, which is still believed by most authors to be reactive ... more Synovial chondromatosis is a rare lesion, which is still believed by most authors to be reactive rather than neoplastic. We report on a case of synovial chondromatosis with clonal chromosomal changes [43,XX,der (1) t (1;13) (p21-22;q21),-6,-13,-14, add(21) (q21)]. The presence of clonal chromosomal changes in this and in three previously reported cases suggests that synovial chondromatosis is a true neoplastic lesion.

Scandinavian Journal of Medicine and Science in Sports, 2002

The goal of this prospective study was to determine the outcome-predictive role of various parame... more The goal of this prospective study was to determine the outcome-predictive role of various parameters in the nonoperative treatment of chronic anterior knee pain patients. Thirty patients followed a five-week treatment program, which consisted out of only closed kinetic chain exercises. Prior to this treatment all subjects were evaluated on muscular characteristics, subjective symptoms, weight, sex, duration of symptoms and functional performance. A multiple stepwise regression analysis revealed that the reflex response time of m. vastus medialis obliquus (VMO) (P=0.041; 0.026), and the duration of symptoms (P=0.019; 0.045) were the only two parameters which were significantly associated with the outcome (evaluated by the Kujala score) at five weeks, and at three months. The shorter the duration of symptoms, or the faster the reflex response time of VMO prior to the treatment, the better the outcome after a closed kinetic chain exercise program. The statistical significance of these parameters in this study may be seen as an indication of the importance of these variables as predictors of the outcome of a closed kinetic chain strengthening program. Using this information, it seems clinically important to begin the treatment program before the anterior knee pain becomes more chronic and treatment results become less good.

Scandinavian Journal of Medicine and Science in Sports, 2003

The purpose of this prospective randomized intervention study was to evaluate the effect of two e... more The purpose of this prospective randomized intervention study was to evaluate the effect of two exercise protocols on reflex response time of vastus medialis obliquus (VMO), vastus lateralis (VL), in patients with anterior knee pain. Sixty patients were randomized into a 5-week treatment program, which consisted of only open kinetic chain tonification exercises (group I) (n = 30), or only closed kinetic chain tonification exercises (group II) (n = 30). Assessment of an aspect of neuromotor control was obtained by measuring the reflex response times of VMO and VL at the time of initial clinical examination, at the end of the exercise period (five weeks), and three months after the completion of the exercise period. At these evaluation occasions, the intensity and the number of times that the patients experienced anterior knee pain during daily life was recorded on a Visual Analog Scale (VAS). No alterations in reflex response times of VMO and VL were observed in either group. Changes of anterior knee pain over time were statistically significant in both groups. Only small and not statistically supported differences in anterior knee pain were found between the two groups. These results suggest that the reflex response times of the two vasti muscles can not be altered after a five week open or closed kinetic chain exercise program. In contrast, knee pain decreased significantly in both groups.

Physiotherapy Theory and Practice, 2011

The major aim of the study was (1) to compare the physiotherapy management in patients treated wi... more The major aim of the study was (1) to compare the physiotherapy management in patients treated with autologous chondrocyte implantation (ACI) versus microfracture (MF) at the knee using a standardized rehabilitation protocol; and (2) to investigate the effect of activities in low-load conditions after surgery on the functional recovery was explored. 95 physiotherapists received a standardized rehabilitation protocol that was used in a randomized controlled trial. A secondary analysis on patients' outcome was studied in a cohort design. An electronic report form including 18 physiotherapy variables was used to compare physiotherapy management. Patients' functional outcome was assessed using the KOOS (Knee Injury Osteoarthritis Outcome Score) and the pooled symmetry index (SI) based on one strength and three hop tests. Both subjective and objective outcomes were evaluated pre-surgery, and at 1 and 2 years post-surgery. 65 physiotherapists adhered very consistently to the protocol during the first 3 months and showed a similar preference and timing for the physiotherapy modalities in both treatment groups. Patients with high amount of low-load activities (LLA+, n=21) post-surgery performed significantly better compared to patients with low amount of LLA (LLA-, n=17). At 24 months the mean pooled SI of LLA+ cohort was 92.4 compared to 78.2 for LLA- cohort (95% confidence interval [CI] 1.8 to 26.2). Overall, the compliance post-surgery with the rehabilitation protocol was excellent and the applied rehabilitation was comparable in both treatment groups. A high amount of low-load activities post-surgery appears beneficial for the objective functional outcome.

Osteoarthritis and Cartilage, 2007

Osteoarthritis and Cartilage, 2007

Purpose: The aim of work was to analyze clinical effectiveness of fresh bone marrow and periosteu... more Purpose: The aim of work was to analyze clinical effectiveness of fresh bone marrow and periosteum versus autologous chondrocytes in treatment of traumatic and degenerative cartilage defects. Methods and Materials: There were 30 patients involved into this study, with mean age of 37 years. Patients were randomly operated either with chondrocytes or fresh bone marrow. Bone marrow was aspirated from iliac crest and implanted under the periosteum sutured over the defect. Chondrocytes were isolated, cultured, than implanted under collagen membrane. Patients followed same rehabilitation protocol. At 12, 24 and 36 months postoperatively, patients were evaluated with analogue pain scale, Brittberg-Peterson VAS score, Lysholm and IKDC questionnaires. Patients were evaluated with MRI 3 and 12 and 24 months postoperatively. In 3 patients of each group tissue samples were obtained for histological assessment. Results: After 36 months, 12 patients treated with bone marrow were Purpose: It may be expected that a two-step open surgery with characterized chondrocyte implantation (CCI) would be disadvantageous to the pace of knee function recovery compared to a one-step arthroscopic microfracture procedure. The objective was to assess the index knee function in patients following an identical, standardized rehab protocol, as part of a prospective randomized clinical trial comparing CCI to microfracture in treating symptomatic cartilage defects of the knee. Methods and Materials: CCI (N=51) and microfracture (N=61) patients were assessed preoperatively and at 6, 9, and 12 months post operatively. Mobility (AROM), Anterior Laxity (with KT1000), Isokinetic Strength (by peak torque at 60°) and Functionality (with a single hop, the crossover triple hop and timed hop test) were evaluated. Of 112 evaluable patients, 100 completed the mobility tests, 85 the functional tests, 75 the strength tests and 65 of the patients completed the anterior laxity tests. Completion rate was equally divided among both groups. Results: both treatment groups preoperatively. Also at 6, 9 and 12 months no four tests, except at 9 months the difference for quadriceps strength for the microfracture group (Med =186) compared to the CCI group (Med= 144) was

Knee Surgery, Sports Traumatology, Arthroscopy, 2011

Implant registries have been effective in detecting poorly performing implants and surgical strat... more Implant registries have been effective in detecting poorly performing implants and surgical strategies. They learn us however little about many variables that may be equally important to the final result. Today, no standards of care exist for performing total knee arthroplasties (TKA), and little is known about the variability that exists amongst surgeons performing this procedure. A questionnaire with 39 aspects regarding standard surgical routine during TKA was sent to all 112 members of the Belgian Knee Society. Surgeons were stratified according to surgical experience and surgical volume. An important number of routines were performed as standard by the majority (>70%) of surgeons. Surgeons however significantly differed in the following aspects of the procedure: radiographic evaluation, use of minimally invasive surgery (MIS), preferred landmark for femoral component rotation, method of closure and activities allowed postoperatively. Both surgical experience and surgical volume had a significant effect, but their influence on strategies was different. Less-experienced surgeons used the posterior condylar line as their reference for femoral component rotation significantly more frequent than more-experienced surgeons and were more aggressive towards postoperative sports activities compared to more-experienced surgeons. High-volume surgeons used significantly more frequent MIS and low-volume surgeons preferred a more extensive postoperative radiographic evaluation. Data of this study show that an important number of routines are performed similarly by the majority of surgeons, and that minor but significant differences exist between high-volume versus low-volume surgeons, and between experienced versus less-experienced surgeons. Case series, Level IV.