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Biomedical subjects

D Rosenbaum

Publications and source records attributed to D Rosenbaum.

At least 19 recordsLinked to original sources
PubMed2002

[What influence do size and placement of patella resurfacing have on knee endoprosthesis?].

The aim of this study was to document the changes in retropatellar pressure, contact area and forces due to different sizes and placement of the patella resurfacing in knee arthroplasty. Six cadaver specimens (after Thiel fixation) were examined after the implantation of the total knee arthroplasty Genesis I. The patella sizes "small" and "medium" were placed as the "onlay" version, centered as well as off-centered by 0.4 cm in all four directions. Pressure and area measurements were done with Fuji pressure measuring film, which was placed between the patellar fascia of the femur and the patella in a defined position. The pressure was measured by applying a predetermined force for 5 s. The examinations were done with 60 degrees knee flexion and a force of 280 N. In our results there were no significant differences between, patella sizes. No significant differences for the medial, distal and proximal placement were found for the small patella. The lateral placement led to a significant decrease in the contact area (P = 0.0277), maximum pressure (P = 0.0422) and force (P = 0.0277). The average pressure did not change significantly (P = 0.1159). For the medium size patella there were no significant differences for medial or distal placement. The comparison of lateral and central placement revealed a significant decrease in the contact area (P = 0.0446). Comparing distal and proximal positioning, a significant increase in contact area and significant decrease in force were found (P = 0.0277 and P = 0.0277 respectively). In conclusion, the choice of small or medium patella resurfacing does not seem to have a significant influence. In comparison to the results without patella implants, the implantation of the small patella caused a significant decrease in the retropatellar contact area (P = 0.03) and force (P = 0.03). Average and maximum pressure did not change significantly (P = 0.6 and P = 0.35) even though pressure increased slightly. For the medium size, maximum pressure (P = 0.03) increased significantly and force decreased significantly (P = 0.0277) whereas contact area and average pressure increased slightly. The results of the different placements of the patella implant do not support the recommendation for a medial shift. However, at least the lateralized implantation led to a reduction of contact area and force as well as to a slight increase of pressure which is considered as unfavorable.

Aged↗
PubMed2001

[Clinico-functional results of constrained knee endoprostheses].

AIM OF THE STUDY: To assess the clinical and functional outcome after implantation of a constrained knee arthroplasty. MATERIAL AND METHODS: 14 patients with a revision of the primary prostheses with constrained knee arthroplasties ("Genesis constrained" and "Blauth") were evaluated in the operated and non operated leg at an average follow-up of 8.5 months (range 6.5 to 61.4 months). The study included clinical examinations as well as gait analysis and surface electromyography. The results were compared with a group of healthy volunteers. The clinical examinations were scored with the HSS, the Knee Society Score, the Tegner Activity Score, the Patella Score and the Visual Analogue Scale. Gait analysis was performed with a three dimensional motion analysis system. Surface electromyography was evaluated bilaterally from the rectus femoris, vastus medialis and lateralis, semitendinosus, biceps femoris (long head), tibialis anterior and gastrocnemius (medial head). RESULTS: The comparison between the healthy volunteers and the patients showed significant functional deficits in the patient group. The electromyography demonstrated significantly lower peak amplitudes in 5 of 7 muscles. In all parameters--except for knee extension--gait analysis resulted in significant differences between the patient and control group. The comparison between the operated and non operated leg showed a significant difference only for knee extension. The patients revealed a bilateral functional deficit so that gait symmetry was preserved. CONCLUSION: The presented results indicate that the functional deficits may be caused by preoperative deficits and are not only due to the operation. It can be supposed that the gastrocnemius is more important because of the high correlation with the clinical results. The value of pre- and postoperative rehabilitation programs to prevent postoperative functional deficits can be concluded.

Aged↗
PubMed2001

[Intra-articular and plantar pressure distribution of the ankle joint complex in relation to foot position].

Ankle injuries are often followed by degenerative changes in the hindfoot joints. Knowledge about the pressure distribution of the intact ankle joint may help to understand the mechanisms leading to cartilage damage. Therefore, we determined the intraarticular and plantar pressure distribution of the ankle joint complex and the Chopart joints with varying foot positions. 12 human lower leg specimens were axially loaded in a foot-loading simulator with full body weight (600 N). A capacitive pressure distribution platform was used to determine plantar pressure patterns. The intraarticular loading situation was measured with Fuji Prescale film. 3 different foot positions (neutral, 10 degrees dorsiflexion, 10 degrees plantarflexion) were investigated. Dorsiflexion led to an increase of the intraarticular contact area, force and mean pressure in the hindfoot. Plantarflexion instead increased loading in the Chopart joints. In the plantar pressure distribution force and peak pressure under the hindfoot increased with dorsiflexion. With plantarflexion area, force and peak pressure under mid- and forefoot increased. With our study we could demonstrate that the loading situation of the ankle joint complex is significantly influenced by the foot position. These findings may help to understand the development and localisation of arthritic changes due to posttraumatic changes of the joint loading characteristics.

Ankle Injuries↗
PubMed2001

Rotationplasty type B IIIa according to Winkelmann: electromyography and gait analysis.

After resection of a malignant bone tumor of the femur, rotationplasty is considered a treatment option in addition to other limb salvage procedures such as endoprosthetic replacement, allograft, or autograft reconstruction. A Type B IIIa rotationplasty is indicated when the tumor involves the total femur or when skip lesions are detected. After the total femur is resected, the lateral tibial plateau is placed into the acetabulum after rotating the tibia and foot segment 180 degrees. Eight patients at an average age of 5.9 years underwent a rotationplasty Type B IIIa at the authors' institution. After a median followup of 59.6 months (range, 24-86 months) the clinical results were excellent and the functional status according to the criteria of the Musculoskeletal Tumor Society was good (23 of 30 points). In electromyographic analysis the muscle activity of the affected leg revealed good function of the stance and the swing phase muscles according to their new function with comparable amplitudes to the unaffected limb. The kinematics (range of motion of the hip and knee) were slightly assymmetric. Gait analysis showed a slight lateral trunk lean over the ipsilateral limb with reduced joint moment. All patients had full weightbearing ability. Remodeling of the tibial plateau into a round form mimicking a new femoral head is confirmed by radiographs and magnetic resonance imaging scans. In young children with a tumor of the total femur, rotationplasty Type B IIIa is a good treatment modality with excellent clinical and good functional results. The electromyographic and gait analysis data underscore a good functional restoration of gait after rotationplasty.

Bone Transplantation↗
PubMed2001

A multi-station proprioceptive exercise program in patients with ankle instability.

PURPOSE: The aim of the present study was to investigate the effects of a 6-wk multi-station proprioceptive exercise program that is easy to integrate in normal training programs. METHODS: Patients with chronic ankle instability were used, and results of three testing procedures before and afterward were compared: joint position sense, postural sway, and muscle reaction times to sudden inversion events on a tilting platform. A total of 30 subjects with 48 unstable feet were evaluated (exercise group: N = 31; control group: N = 17). RESULTS: In the exercise group, the results showed a significant improvement in joint position sense and postural sway as well as significant changes in muscle reaction times. CONCLUSION: Based on the present results, a multi-station proprioceptive exercise program can be recommended for prevention and rehabilitation of recurrent ankle inversion injuries.

Adult↗
PubMed2001

[Results of bicondylar sledge prostheses with special reference to the gait pattern].

AIM: To establish whether the clinical results obtained with bicondylar sledge prostheses correlate with clinical findings, and whether clinical results influence gait pattern. MATERIAL AND METHODS: 15 patients with bicondylar sledge prostheses were compared with healthy controls. The clinical examination was documented using the HSS, Knee Society, Tegner, and patella scores, and the Visual Analogue Scale. Gait analysis was done with a three-dimensional motion analysis system and force platforms. RESULTS: A comparison of patients and controls showed significant differences in the clinical results, whereas the parameters gait function, muscle force and pain did not. No significant differences were found between the operated and non-operated legs. In comparison with controls, patients showed significant differences in the ground reaction forces. DISCUSSION: The abnormal gait findings showed no correlation with clinical results, nor did such parameters as age, weight and duration of follow-up appear to have any influence. The non-operated leg adapted to the gait pattern of the operated leg, to restore gait symmetry. CLINICAL RELEVANCE: Subjective complaints or clinical results show little relationship to gait parameters in patients receiving a bicondylar sledge prosthesis.

Aged↗
PubMed2001

Genome scan of idiopathic generalized epilepsy: evidence for major susceptibility gene and modifying genes influencing the seizure type.

Idiopathic generalized epilepsy (IGE) is a common, complex disease with an almost exclusively genetic etiology but with variable phenotypes. Clinically, IGE can be divided into different syndromes. Varying lines of evidence point to the involvement of several interacting genes in the etiology of IGE. We performed a genome scan in 91 families ascertained through a proband with adolescent-onset IGE. The IGEs included juvenile myoclonic epilepsy (JME), juvenile absence epilepsy (JAE), and epilepsy with generalized tonic clonic seizures (EGTCS). Our linkage results support an oligogenic model for IGE, with strong evidence for a locus common to most IGEs on chromosome 18 (lod score 4.4/5.2 multipoint/two-point) and other loci that may influence specific seizure phenotypes for different IGEs: a previously identified locus on chromosome 6 for JME (lod score 2.5/4.2), a locus on chromosome 8 influencing non-JME forms of IGE (lod score 3.8/2.5), and, more tentatively, two newly discovered loci for absence seizures on chromosome 5 (lod scores 3.8/2.8 and 3.4/1.9). Our data also suggest that the genetic classification of different forms of IGE is likely to cut across the clinical classification of these subforms of IGE. We hypothesize that interactions of different combinations of these loci produce the related heterogeneous phenotypes seen in IGE families.

Adolescent↗
PubMed2000

No evidence for a major susceptibility locus for juvenile myoclonic epilepsy on chromosome 15q.

Juvenile myoclonic epilepsy (JME) is a distinct epileptic syndrome with a complex mode of inheritance. Several studies found evidence for a locus involved in JME on chromosome 6 near the HLA region. Recently, Elmslie et al. [1997] reported evidence of linkage in JME to chromosome 15q14 assuming a recessive mode of inheritance with 50% penetrance and 65% linked families. The area on chromosome 15q14 encompasses the location of the gene for the alpha-7 subunit of the nicotinic acetylcholine receptor. This could fit the hypothesis that there are two interacting loci, one on chromosome 6 and on chromosome 15 or that there is genetic heterogeneity in JME. In an independent dataset of JME families, we tested for linkage to chromosome 15 but found little evidence for linkage. Moreover, families with more than one family member affected with JME provide a lodscore of 3.4 for the HLA-DR/DQ haplotype on chromosome 6. The lodscore for these same families on chromosome 15q14 is <-2 assuming homogeneity and the maximum lodscore is 0.2 assuming alpha =.25. Only one of these families has a negative lodscore on chromosome 6 and a positive lodscore of 0.5 on chromosome 15q14. Our results indicate that this possible gene on chromosome 15 plays at most a minor role in our JME families. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:49-52, 2000.

Chromosome Mapping↗
PubMed2000

[What retropatellar changes result by implantation of a superficial knee joint prosthesis?].

The aim of this study was to evaluate the retropatellar pressure, force, and contact area in cases of knee arthroplasty compared to knees without arthroplasty. We examined six leg specimens before and after knee arthroplasty. The modified Thiel fixation was used, and arthroplasty was the Genesis I without patellar implant (Fa. Smith & Nephew, Schenefeld). Contact measurements were performed with pressure-sensitive film (Fuji Prescale type "super low") in 45 degrees, 60 degrees, 90 degrees, and 120 degrees knee flexion. The results were evaluated with special software, "Pressure Imaging and Analyzing System FPD-901 Series". The leg was exarticulated in the hip joint and the knee joint was opened from a suprapatellar approach. The film was placed at a defined area between the facies patellaris of the femur and facies articularis of the patella. Instantaneous pressure was measured during a time of 5-s pressure increase and a further 5 s. A force of 280 N was applied to the quadriceps muscle. Before knee arthroplasty, the contact area measured 154.3 mm2, the average pressure was 1.14 MPa, the force 182.13 N. After knee arthroplasty, the contact area was 119.94 mm2, the average pressure 1.522 MPa, the force 180.98 N. Following knee arthroplasty the contact area decreased significantly (P = 0.015), and the average (P = 0.0001) and maximum pressure (P = 0.0003) increased significantly. The force did not change significantly (P = 0.7642). The choice of the knee arthroplasty implant and approach to the knee joint should be considered in order to achieve an increased retropatellar contact area thus preventing smaller contact areas than before knee arthroplasty. The increased contact area could also prevent increasing retropatellar pressures after knee arthroplasty and further complications.

Aged↗
PubMed2000

Retropatellar contact characteristics in total knee arthroplasty with and without patellar resurfacing.

Total knee replacement with and without patellar resurfacing was performed in 6 cadaver specimens. The contact pressure and contact area between femur and patella was measured at 60 degrees of flexion. In comparison to specimens without resurfacing the specimens with small size resurfacing showed a significant decrease in contact area, whereas average and maximum pressure were unchanged. In specimens with medium size resurfacing, contact area and average pressure increased slightly, whereas maximum pressure increased significantly. Patellar resurfacing did not change the retropatellar pressure, but was associated with reduced contact area.

Aged↗
PubMed2000

Reliability of peroneal reaction time measurements.

OBJECTIVE: The purpose of this study was to demonstrate the reliability of reaction time-measurements on a tilting platform under consideration of various influencing factors. DESIGN: The peroneal reaction time of 30 healthy subjects was examined in an experimental study. BACKGROUND: Peroneal reaction time measurements have been used to objectively evaluate functional instability of the ankle joint, but the reliability of the method has not been proven yet. METHODS: The reaction time after sudden inversion of the ankle were determined by surface EMG. RESULTS: The median latency of the peroneus brevis was 66 ms and that of the peroneus longus was 63 ms. No differences between male and female subjects and between left and right legs could be found. An increase of reaction time was caused by neuromuscular fatigue (P=0.033, for both the peroneus brevis and the peroneus longus). A decrease in reaction time resulted if the foot was held in 15 degrees of plantar flexion (P=0.0004 for the peroneus brevis, P=0.002 for the peroneus longus). The reliability was examined by circadian and by day-to-day measurements. The coefficient of correlation (Spearman's rho) between the peroneus brevis and days 1-5 was 0.67 (P=0.177) and for the peroneus longus 0. 00 (P0.999). The same results were obtained after the circadian measurements. CONCLUSION: Determination of peroneal reaction time was proven as a reliable measurement method. RELEVANCE: Reliability and validity are basic preconditions of a test to become accepted as a clinical measurement method. This paper demonstrates the reliability of measuring the peroneal reaction time. Thus, assuming validity, the peroneal reaction time measurement is justified as a clinical test.

Adult↗
PubMed2000

Plantar and dorsal foot loading measurements in patients after rotationplasty.

OBJECTIVE: The present study investigated the plantar and dorsal foot loading patterns inside the prosthesis of patients after rotationplasty. DESIGN: In vivo foot pressure distribution measurements during free walking in rotationplasty patients at an average follow-up of 10.4 years after surgery. METHODS: Fourteen subjects participated in the study and were measured during free walking. Capacitive pressure sensitive insoles were worn inside the shaft of the prosthesis either on the plantar or the dorsal aspect of the foot. Between 5 and 15 steps (mean 10.5) during full gait were selected and averaged to present a typical loading pattern for the individual patient. RESULTS: The measurements were reproducible and indicated that the main loading areas of the rotated foot inside the prosthesis are medially on the dorsal aspect and in the heel and toe region or the heel and midfoot region on the plantar aspect. The dorsal loading area was smaller than the plantar area (P=0.003). The force was higher on the plantar than on the dorsal aspect (P=0.005) but the loading time was shorter (P=0.008). In patients with callosities the high pressure areas coincided with the affected regions. CONCLUSIONS: The information gained from the pressure measurements support the understanding of foot loading characteristics in this anatomically and biomechanically unusual situation. This knowledge may be used to support the fitting process of new prosthetic designs for patients after rotationplasty. RELEVANCE: Foot loading capacity is one of the main factors limiting the activity level of rotationplasty patients. Therefore, a better understanding of foot loading characteristics might help to prevent overloading of certain foot structures and eventually improve the prosthetic fit with a direct benefit to the individual patient.

Adolescent↗
PubMed2000

Reproducibility and complications in gene searches: linkage on chromosome 6, heterogeneity, association, and maternal inheritance in juvenile myoclonic epilepsy.

Evidence for genetic influences in epilepsy is strong, but reports identifying specific chromosomal origins of those influences conflict. One early study reported that human leukocyte antigen (HLA) markers were genetically linked to juvenile myoclonic epilepsy (JME); this was confirmed in a later study. Other reports did not find linkage to HLA markers. One found evidence of linkage to markers on chromosome 15, another to markers on chromosome 6, centromeric to HLA. We identified families through a patient with JME and genotyped markers throughout chromosome 6. Linkage analysis assuming equal male-female recombination probabilities showed evidence for linkage (LOD score 2.5), but at a high recombination fraction (theta), suggesting heterogeneity. When linkage analysis was redone to allow independent male-female thetas, the LOD score was significantly higher (4.2) at a male-female theta of.5,.01. Although the overall pattern of LOD scores with respect to male-female theta could not be explained solely by heterogeneity, the presence of heterogeneity and predominantly maternal inheritance of JME might explain it. By analyzing loci between HLA-DP and HLA-DR and stratifying the families on the basis of evidence for or against linkage, we were able to show evidence of heterogeneity within JME and to propose a marker associated with the linked form. These data also suggest that JME may be predominantly maternally inherited and that the HLA-linked form is more likely to occur in families of European origin.

Alleles↗
PubMed2000

Electromyographic and gait analysis of forty-three patients after rotationplasty.

BACKGROUND: Rotationplasty is considered to be a treatment option for patients who have had a primary malignant bone tumor of the distal part of the femur or the proximal part of the tibia. The present study was performed to evaluate the muscle activity, the kinetics (range of motion of the hip and knee joints), and the kinematics (joint moments) after rotationplasty and to determine whether there was an association between these parameters and the functional outcome. METHODS: Forty-three patients who had been managed with rotationplasty for the treatment of a femoral or tibial bone tumor were evaluated clinically and functionally. The mean age (and standard deviation) at the time of follow-up was 24.4 +/- 10.7 years (range, eight to sixty-eight years), the mean age at the time of the procedure was 17.8 +/- 10.2 years (range, seven to sixty-three years), and the mean duration of follow-up was 6.7 +/- 4.9 years (range, 0.7 to eighteen years). Instrumented gait and electromyographic analyses were performed. The qualitative data were compared with the functional outcome, which was determined with the functional evaluation score of the Musculoskeletal Tumor Society. RESULTS: Gait analysis revealed a fairly normal walking pattern with a slight limp and a lateral lean of the trunk over the ipsilateral limb that led to a reduced joint moment in the hip (moment on involved side, 68 percent [compared with a control group]; moment on uninvolved side, 81 percent). The ranges of motion of the hips (uninvolved side, 42.0 +/- 8.2 degrees; involved side, 42.4 +/- 8.0 degrees) and the knees (uninvolved side, 59.7 +/- 5.0 degrees; involved side [former ankle joint], 58.1 +/- 11.6 degrees) were symmetrical even though the knee-motion pattern of the involved limb indicated a slightly reduced extensor mechanism in 51 percent (twenty-two) and a markedly reduced extensor mechanism in 35 percent (fifteen) of the forty-three patients. Electromyography revealed function of the muscles of the involved limb, with comparable amplitudes in the involved and uninvolved limbs. The leg muscles of the involved limb were active in the stance phase (the soleus and the lateral and medial heads of the gastrocnemius) and the swing phase (the peroneus longus and the tibialis anterior) according to their function in relation to the new knee joint. The patients had a good functional result, with a mean score of 23.9 +/- 2.7 of 30 points. With the numbers available for study, we could not show the duration of follow-up to be related to the overall outcome, but the age at the time of the operation was related to the total functional score as well as to gait and walking ability (p < 0.05). CONCLUSIONS: The results of the electromyographic and gait analyses demonstrated good functional restoration of gait following rotationplasty.

Adolescent↗
PubMed1999

[Ankle orthotic devices. Review, areas of application and scientific results].

The present paper is concerned with the importance of braces and orthotic devices for the treatment of functional deficits of the lateral ankle ligaments. After a short description of the different categories, the various areas of application are described. Finally, the effects of these orthopaedic devices with respect to joint stabilisation, injury prevention, and the influence on proprioception and sports performance are discussed based on research reports.

Ankle Injuries↗