Biomedical subjects

B Friemert

Publications and source records attributed to B Friemert.

At least 19 recordsLinked to original sources

PubMed2006

Changes in stretch reflex excitability are related to "giving way" symptoms in patients with anterior cruciate ligament rupture.

A rupture of the anterior cruciate ligament (ACL) usually leads to an altered stretch reflex excitability of the thigh muscles that stabilize the knee. The purpose of this study was to quantitatively assess reflex activity in the m. semitendinosus/semimembranosus after anterior tibial translation in 21 patients with isolated ACL ruptures. The patients were divided into a group with "giving way" symptoms (noncopers, n = 12) and a group without "giving way" symptoms (copers, n = 9). While the patients were standing upright with 30 degrees knee flexion, a force of 300 N was applied to the knee to induce posterior-anterior tibial translation. Activity of m. semitendinosus/semimembranosus was measured using surface electromyography (EMG). A linear potentiometer was placed on the tibial tuberosity and measured maximum tibial translation during standing (i.e., functional condition). In addition, knee laxity was assessed with a KT1000 arthrometer under passive conditions. After ACL rupture, the short-latency response (SLR) latency remained unchanged (P = 0.21), whereas for the medium-latency response (MLR) it was significantly longer (P < 0.001). Significantly longer MLR latencies were noted for noncopers compared with copers (P < 0.01), whereas SLR latencies were similar. Significant differences between healthy and injured legs were noted after tibial translations using KT1000 (P < 0.001) and during stance (P < 0.001). Mechanical knee instability was found to be unchanged between copers and noncopers (KT1000: P = 0.97; tibial translation: P = 0.31). These results indicate that ACL rupture is associated with altered stretch reflex excitability, which may lead to "giving way" symptoms, and that altered stretch reflex excitability may be more important for the development of "giving way" than the mechanical instability of the knee.

Adult↗

PubMed2006

[On informed patient consent].

One third of all lawsuits against doctors include statements of insufficient or lacking informed consent. The objectives of this prospective study in 104 patients were to elucidate the actual clinical routine of obtaining informed consent (process quality), collect information on active and passive recall 3 to 7 days p.op., and to investigate whether patient age, sex, education, profession, and cognitive function using the Mini Mental State Test, the time from obtaining consent to interview, acuity (emergency vs elective cases), and quantity of patient/doctor interaction would influence the patient's recall capabilities. In clinical routine, obtaining informed consent is a very variable procedure, and between two and 18 items were documented by the physician. Of the patients, 12.6% recalled actively and 43.5% passively. They named between 1.1 and 3.7 items on average, with "infection" as the leading complication, followed by "pain" and "lesion of nerves". Of all parameters investigated, only the number of initially documented items exhibit a significant effect on the patients' recall. The quantity of patient/physician interaction not only guarantees an increased effect on recall but also means improves patient interaction, thereby reducing the probability of imminent accusations.

Adolescent↗

PubMed2006

[The influence of a controlled active motion splint on proprioception after anterior cruciate ligament plasty. A prospective randomized study].

BACKGROUND: A ruptured anterior cruciate ligament (ACL) leads to both mechanical and functional instability. Functional instability is caused by proprioceptive deficit. The aim of this study was to determine whether the proprioceptive deficit can be reduced by using a controlled active motion (CAM) splint postoperatively. PATIENTS AND METHODS: A total of 50 patients with ACL rupture were randomized into two groups. After ACL plasty the PT group received postoperative physiotherapy, while the CAM group were managed with a CAM splint and physiotherapy. Proprioceptive ability was measured with a passive angle-reproduction test. RESULTS: On the day of discharge 80% of the patients in the CAM group and 25% in the PT group had a reduced proprioceptive deficit. Overall the main measured value in the CAM group improved by 83.7%, but deteriorated by 39.3% in the PT group. There was no significant difference between the CAM group and a healthy control group. CONCLUSION: Using a CAM splint in addition to physiotherapy after ACL plasty in comparison to physiotherapy alone decreases the proprioceptive deficit significantly. We recommend the use of a CAM splint in the postoperative management following ACL plasty.

Anterior Cruciate Ligament↗

PubMed2005

Benefits of active motion for joint position sense.

Anterior cruciate ligament (ACL) ruptures lead to a proprioceptive deficit and therefore joint position sense. This study examined whether active motion is better suited than passive motion to address this deficit. Sixty patients with ACL rupture were prospectively randomised into two groups [continuous active motion (CAM)/continuous passive motion (CPM)]. All patients had an ACL reconstruction. An angle reproduction test was used to assess the proprioceptive deficit. The relevant examinations were performed before surgery (pre-op evaluation) and after the seventh postoperative day. No preoperative difference was found between the two groups. After postoperative treatment, the deficit was reduced in both groups. Significantly better results were, however, obtained in the CAM group (CPM, 4.2+/-1.6 degrees; CAM, 1.9+/-1.2 degrees; P<0.001). During the first postoperative week, a CAM device produced a significantly greater reduction in the proprioceptive deficit and should be the first choice in immediately postoperative rehabilitation after ACL replacement.

Adolescent↗

PubMed2005

Intraoperative direct mechanical stimulation of the anterior cruciate ligament elicits short- and medium-latency hamstring reflexes.

The anterior cruciate ligament (ACL) has not only a mechanical but also a sensorimotor function. Patients with injuries of the ACL frequently complain of knee instability despite good mechanical stabilization after surgical reconstruction. Compared with healthy subjects, their latencies of hamstring reflexes after anterior tibia translation are considerably increased. There is evidence for the existence of a reflex arc between the ACL and the hamstrings. The aim of this study was to determine if there is a direct reflex response after an isolated mechanical stimulation of the ACL in humans. In 10 patients who underwent arthroscopy, hamstring electromyographic (EMG) responses were assessed intraoperatively after applying an isolated load on the ACL. Latencies, amplitudes, and integrals of the EMG responses were analyzed. In four patients, the measurements were repeated after injection of local anesthetics into the ACL. In all subjects, responses with mean latencies of 42 +/- 4.4 (SD) ms corresponding to a medium latency response (MLR) were found. In seven subjects, they were preceded by responses with a short-latency (SLR) of 24 +/- 2.7 ms. The maximum amplitude was 8.6 +/- 7 mV, the integral 0.064 +/- 0.05 mV*s. The injection of local anesthetics reduced the amplitude by 34 +/- 12% and the integral by 50 +/- 20%. Direct mechanical stimulation of the ACL evokes considerably smaller SLRs and MLRs than anterior tibia translation during standing. It is argued that latency changes observed in patients with ACL ruptures may be rather due to changes in the sensorimotor integration of the afferent input from the knee joint than to the absence of the direct ACL reflex.

Adult↗

PubMed2005

[Clinical results with A new retrograde femoral nail with a radiographical-free proximal locking device. A prospective study with 50 fractures].

INTRODUCTION: Conventional retrograde nailing of the femur causes two important disadvantages: the proximal locking of the nail is difficult because of the anatomic conditions and a chondral defect was left into the knee. MATERIAL AND METHODS: After the retrograde implantation the new nail was lead through the greater trochanter. An additional proximal aiming device for proximal interlocking can be fixed. The entrance portal will be sealed by an osteochondral cylinder. 50 cases of femur fractures were selected for the prospective study. We recorded all intraoperative complications and technical difficulties. The cases were followed up for 52 weeks, both clinical and radiology examinations were performed. RESULTS: The mean follow up was 15.5+/-5 months. All fractures were healed. Knee movement was 125+/-14 degrees. The Leung Score was 84+/-12.6 points; HSS Score was 90+/-9 points. In two cases wound infections were developed. Mal-union was observed in three cases, in two cases nail brake down. CONCLUSIONS: The new retrograde interlocking nail could be used to manage femur fractures successfully. Two aiming devices enable a easy interlocking. Replacement of the osteochondral cylinder into the entry portal reduces cartilage damage.

Adolescent↗

PubMed2005

[Removal of a thoracic impaling agent without direct observation. The significance of pre-operative diagnosis].

Impalement injuries are uncommon and only occasional reports exist in the literature, resulting in non standardized approaches. Depending on the location, completely different combinations of injuries occur, making every impalement unique. Nevertheless some basic principles for dealing with impalements exist. These principles, and some controversial statements in the literature on the value of preoperative diagnostics, especially CT, are discussed using the example of a spectacular thoracic impalement by a 2 x 2 cm square metal pole. Our deviation from the principal of removing an impaling object only under direct observation in this special case is also discussed.

Adult↗

PubMed2005

Differentiation of hamstring short latency versus medium latency responses after tibia translation.

After injuries to the anterior cruciate ligament (ACL) a functional instability is frequently observed which has been attributed to a disturbed sensorimotor function. In light of the clinical importance of ACL injuries and the resulting functional instability, it is of enormous clinical interest to elucidate the role of sensorimotor pathways that involve the ACL. In animals and humans a direct reflex pathway between the ACL and the hamstrings has been shown. The onset latencies of responses reported after ventral tibia translation were around 40-50 ms (range 17.9-65) and were regarded as medium latency responses (MLR). However, ventral tibia translation should also induce a stretch of the hamstring muscles and evoke a short latency response (SLR). Before any muscle response after ventral tibia translation can be ascribed to anatomical structures, it is crucial to analyze the obtained muscle responses carefully. The aim of the present study was the development of an algorithm to differentiate SLR and MLR responses after ventral tibia translation. In ten healthy subjects reflex responses of the hamstrings after anterior tibia translation and after tendon taps on the biceps femoris tendon were evaluated. To investigate the influence of skin afferents, control experiments were performed after lidocain injection of the dorsal calf. The mean onset latency of the tendon jerk reflex was 21.9 +/- 3.1 ms (range 17.3 - 28.7 ms). Both SLR responses (mean onset latency: 20.3 +/- 3.5 ms; range 15.4 - 25.8) and MLR responses (mean onset latency: 38.9 +/- 4.2 ms; range 32.9 - 46.7) were obtained in all subjects. Skin afferents from the calf do not play a major role. The development of an evaluation algorithm is presented that allows a safe differentiation between these partly superimposed SLR and MLR components. It is demonstrated that by measuring the first part of the SLR from the onset to the first peak the end of the SLR can be predicted and that the onset latency of the MLR component can be assessed reliably. Possible reasons are discussed why previous studies only reported responses at MLR latencies. The fact that both SLR and MLR components can be observed after anterior tibia translation underlines the necessity to differentiate the responses before they can be ascribed to any anatomical structures. As a basis for future work the algorithm presented may become a useful tool to differentiate which afferent pathways play a role in initiating hamstring activity.

Adult↗

PubMed2005

Tissue engineering of bone: effects of mechanical strain on osteoblastic cells in type I collagen matrices.

The aim of the present study was to investigate the effect of cyclic uniaxial mechanical strain on a human osteoblastic precursor cell line (hFOB 1.19) in three-dimensional type I collagen matrices. Cell seeded collagen constructs were mechanically stretched by a daily application of cyclic uniaxial strain using a special motor-driven apparatus and compared to unstretched controls. Expression of genes involved in cell proliferation and osteoblastic differentiation as well as matrix production were investigated by analyzing the mRNA of histone H4, core binding factor 1, alkaline phosphatase, osteopontin, osteocalcin, and collagen type I (Col I) up to a cultivation period of 3 weeks using real-time PCR. Cyclic stretching of cell seeded Col I matrices at a magnitude occurring in healing bone increased cell proliferation and slightly elevated the expression of nearly all investigated genes over unstrained controls at various time points. It was concluded that mechanical load promotes the proliferation and differentiation of osteoblastic precursor cells in a Col I matrix and that the application of mechanical stimuli may have a beneficial effect on in vitro tissue formation.

Biocompatible Materials↗

PubMed2005

[Functional ultrasound examination of the posterior cruciate ligament -- a new method of detecting ligament instability in the knee joint].

AIM: Detection of injuries to the posterior cruciate ligament (PCL) is difficult and dismissed in many cases. Here we introduce dynamic ultrasound examination as a safe and reproducible method to detect a PCL-insufficiency with or without fixed posterior tibia position and combined injuries to the cruciate ligament complex. PATIENTS AND METHOD: Dynamic ultrasound examination in a modified technique to Schwarz et al. was performed on 20 patients with a PCL-insufficiency (group 1) and 20 patients with an anterior cruciate ligament (ACL) insufficiency (group 2). Comparing both knee joints, we measured the resting value (RV), ventral translation value (VT) and dorsal translation value (DT). Mean value, standard deviation in mm and t-test for unpaired values were compared with each group and a healthy control population. RESULTS: In group 1 we could distinguish patients with fixed posterior position (PCL (mfix)) who showed a pathological dorsal RV (2.96 mm) from patients without fixation (PCL (ofix),: RV = 0.7 mm). DT was significantly prolonged (PCL (mfix): 6.4 mm; PCL (ofix): 5.6 mm) compared to healthy individuals. Group 2 showed a pathological RV (2,38 mm) and a significant prolonged VT (4.19 mm). 10 patients in this group had a spontaneous ventral tibia translation (RV: 3.7 mm) and 10 patients with ACL insufficiency showed a normal resting value (RV: 0.88 mm). CONCLUSION: Dynamic ultrasound examination allows us to distinguish between isolated ACL- or PCL-insufficiency and combined injuries of the cruciate ligament complex using a standardized flow sheet. PCL-insufficiency therefore can be separated into the entities of fixed posterior and partly reducible instability.

Adult↗

PubMed2004

Anatomical repair of lateral ligaments in patients with chronic ankle instability.

In a prospective study, 19 patients with chronic ankle instability underwent clinical and radiographic reexaminations 36 months after anatomical reconstruction. In addition, dynamic pedography was conducted and peroneal reaction time measured on a tilting platform for an evaluation of functional aspects. Prior to this examination, 32 patients had been asked to fill in a questionnaire and make a detailed subjective evaluation of current discomfort, stability, flexibility and sporting abilities. Eighty-eight percent of the patients reported satisfactory results; only 3% complained of persistent instability. In 71% the ability to take part in sports had improved after surgery, and 85% of the patients reported unrestricted walking abilities. Supination ability was impaired in 5% of the patients at the follow-up. The radiographic examination showed restored ankle stability with a significant reduction of talar tilt and talar translation; a postoperative increase in signs and symptoms of arthrosis was not observed. Dynamic pedography showed a large degree of symmetry of plantar pressure distribution after surgery. There were no significant differences in peroneal reaction time in the repaired and intact ankles. The results of the study show that it is possible to restore ankle stability with anatomical reconstruction without impairing the range of movement in the ankle joint complex. Progressive osteoarthrosis can be prevented.

Ankle Joint↗

PubMed2004

[Treatment of trans-symphyseal instability with an internal fixator. Outcome of a surgical technique on the basis of a case report].

Treatment of traumatic trans-symphyseal instability by internal plate fixation is the most common procedure. Besides the trauma-induced muscle damage, the implantation induces additional damage at the symphyseal origin of the m. rectus abdominis. The aim of this clinical case study was to examine whether it is possible to reduce the iatrogenic soft tissue damage while correcting trans-symphyseal instability using an internal fixator. After a transverse skin incision, two pedicle screws were drilled into the corpus ossis pubis next to the symphysis. Afterwards the crossbar was implanted and fixed. Generally, implantation of two self-trapping pedicle screws using a skin incision with a length of 6 cm is possible. Additional detachment of the m. rectus abdominis is not necessary. As a result of the mobility of the skin and subcutaneous tissue, the implantation of the crossbar beneath the m. rectus abdominis is possible. Stabilization of traumatic trans-symphyseal instability by internal fixation is a safe and easy method. Additional soft tissue damage can be prevented, but to achieve multidirectional stability some small modifications of the implant are necessary.

Bone Plates↗

PubMed2004

[Effects of mechanical strain on human osteoblastic precursor cells in type I collagen matrices].

BACKGROUND: The aim of the present study was to investigate the effect of mechanical strain on human osteoblastic precursor cells in a three-dimensional scaffold. METHODS: Osteoblastic precursor cells were seeded in a collagen type I gel and mechanically stretched by daily application of cyclic uniaxial strain. The expression of histone H4, core binding factor 1, alkaline phosphatase, osteopontin, osteocalcin, and collagen type I was investigated by analysing the mRNA. Cell and matrix orientation were investigated by scanning electron microscopy. RESULTS: Cyclic stretching increased cell proliferation. The expression of osteogenic markers was slightly increased by mechanical strain. The cells and matrix were strictly oriented in the stress direction. CONCLUSION: The application of mechanical load might have a beneficial effect on the quality and quantity of generated bone tissue and might be a important factor in tissue engineering of bone.

Alkaline Phosphatase↗

PubMed2003

Diagnosis of chondral lesions of the knee joint: can MRI replace arthroscopy? A prospective study.

The role of magnetic resonance tomography (MRI) for the diagnosis of chondral lesions of the knee joint is still unclear. The sensitivity of the method ranges from 15% to 96%. The scope of our daily experiences showed that there were considerable deviations between the tomographical and arthroscopical results, which vary from the results of experimental studies. Therefore we have conducted a prospective study to investigate the question of how MRI can replace arthroscopy (ASC) in the diagnosis of cartilage damages in the scope of daily routine. All 195 patients included in this study received a magnetic resonance tomography followed by an arthroscopy. A clear diagnosis of supposition had to be determined before the magnetic resonance tomography. The patients were divided into 3 Groups. Group A (n=86) received a standard Military Hospital Ulm (MH) MRI--sagittal STIR TSE and PD TSE, coronal and transversal T2 FFE (TR=660 ms, TE=18 ms, FA=30 degrees, 512 matrix). In addition, one sub-Group, AK (n=21) was examined with a special cartilage sequence of the cartilage fs T1 W FFE. Neither patients in Group AK nor in Group A as a whole received any contrast medium. Group B (n=88) was examined with an alternate MRI protocol (Radiological Joint Practice, Neu-Ulm--sagittal T1 SE, T2 SE and T2 FLASH (TR=608 ms, TE=18 ms, FA=20 degrees, 256 matrix), coronal PD fs), employing gadolinium as a contrast medium. 156 cartilage lesions were found arthroscopically. In Group A the sensitivity was 33%, the specificity 99%, and the positive and negative prediction values 75% and 98% respectively. Group B reached a sensitivity of 53% and a specificity of 98%. The positive prediction value was 48% and the negative was 98%. Group AK showed a sensitivity of 38% and specificity of 98%; the positive and negative prediction values came to 50% and 97% respectively. In conclusion, our results indicate that the MRI examination techniques recommended in the literature at present are not able to replace the ASC for the diagnosis of cartilage damages of the knee joint. In view of the high specificity (97%-99%) and the high negative prediction value (97%-98%), MRI is suitable for the exclusion of cartilage lesions. For a negative MRI associated with a cartilage injury, a cautious attitude towards an operative cartilage treatment is therefore justified. Because the MRI can not replace the ASC for diagnostic of cartilage damage, the ASC still has to be seen as the method of choice for the evaluation of cartilage damage.

Arthroscopy↗

PubMed2002

[Intramedullary femoral osteosynthesis with the "rendezvous procedure". A new philosophy of retrograde intramedullary nailing].

OBJECTIVE: The disadvantages of retrograde intramedullary nailing are the necessity of explanting the nail through the knee and the occasional difficulties with proximal interlocking. The new retrograde intramedullary nail includes the following innovations: The nail is inserted into the medullary canal beyond the great trochanter, so that a proximal aiming device can be used. The nail is removed through the proximal opening. The distal opening can be closed with the osteochondral cylinder that has been taken out before. MATERIAL AND METHODS: In all, 27 patients have been included in this prospective study. The intraoperative data of the implantation has been recorded. A clinical/radiologic examination took place on the day of discharge and 6-12-26 weeks after the operation in order to record the postoperative complications. RESULTS: The mean time of follow-up examinations at the moment is 8.9 months (2-14). No infections have occurred. The healing of the fractures was without any problems. No patient complained of any major problems concerning the knee and the hip. CONCLUSIONS: The new Sinart-Nail seems to be a nail that can be implanted easily and without complications. It combines the advantages of the retrograde intramedullary nailing with the advantages of the anterograde explantation. The two aiming devices facilitate a distal and proximate fixation without fluoroscopy. The replanting of the osteochondral cylinder reduces internal damage to the knee.

Adolescent↗

PubMed2002

[MRI vs. arthroscopy in the diagnosis of cartilage lesions in the knee. Can MRI take place of arthroscopy?].

INTRODUCTION: The accuracy of magnet resonance imaging in diagnosing cartilage lesions is discussed controversially. The sensitivity of this examination ranges from 15 % to 96 %. Clinical evidence demonstrates that cartilage lesions, diagnosed by MRI, were not confirmed in arthroscopy. The purpose of this prospective study was to analyse the practicability of replacing arthroscopy by MRI in diagnosis of cartilage lesions. PATIENTS AND METHODS: 195 patients with acute or chronic knee pain were examined by reason of a pathological clinic result by MRI preoperatively. In group A (n = 86), a standard program was performed in the radiological department of German Army Hospital (sagittal STIR TSE und PD TSE, coronary und transversal T2 FFE [TR = 660 ms, TE = 18 ms, FA = 30 degrees, 512er-Matrix]), in 21 patients (subgroup AK) a cartilage specific sequence (fs T1 W FFE) without gadolinium was added. Patients in group B (n = 88) were examined in a private outpatient clinic (sagittal T1 SE, T2 SE and T2 FLASH [TR = 608 ms, TE = 18 ms, FA = 20 degrees, 256er-Matrix]) with the use of gadolinium. A clear clinical diagnosis had to be performed before MRI examination. RESULTS: 156 lesions of the cartilage were detected arthroscopically. The sensitivity of the examination was in group A 33 %; group B 53 %; group AK 38 %, specificity in group A 99 %; group B 98 % and group AK 98 %. The positive and negative predictive values were in group A 75 %/98 %; group B 48 %/98 % and in group AK 50 %/97 %. CONCLUSION: MRI was not able to detect reliable cartilage lesions. Until now, arthroscopy is the golden standard to detect cartilage lesions.

Arthroscopy↗

PubMed2000

[A prospective randomized study on inguinal hernia repair according to the Shouldice technique. Benefits of local anesthesia].

OBJECTIVE: The aim of this randomized controlled study was to show whether local anesthesia (LA) leads to a decrease of postoperative pain in inguinal hernia repair in comparison with general anesthesia (AA). METHOD: Sixty volunteer patients were randomly assigned into a LA group and an AA group. All patients had an unilateral primary inguinal hernia and underwent inguinal hernia repair (Shouldice technique). Methods to determine pain were the visual analog scale (VAS), peak flow measurement, the measurement of the FEV1 %, and analgesic consumption. RESULTS: Up to the third postoperative day we measured a decreased pain level in the LA group. The anesthesia procedure was never changed. No essential complications occurred. CONCLUSION: Therefore, it was concluded that local anesthesia has more advantages than general anesthesia.

Adolescent↗

PubMedDate not supplied

[Results 13 years after ACL plasty using a carbon prosthesis].

AIM: The retrospective results of carbon prostheses for ACL plasty from 1985 to 1989 are reported. The aim of this study was to determine the number and kind of necessary revisions and the rate of arthrosis and instability of the operated joints. METHOD: 101 patients out of 136 patients with ACL plasty using a carbon prosthesis could be reviewed clinically in this retrospective study. All patients answered a questionnaire. Additionally, the tibial translation was examined with the KT1000 at maximum power. Conventional X-rays were taken of the knee joints. The results were evaluated using different scores. RESULTS: 70 % of the patients had pathological findings in the clinically tested tibial translation and had a positive Lachmann sign. 66 patients had a tibial translation of 2 mm or above when tested with the KT1000 at maximum power. Radiological studies had shown a gonarthrosis of grades III and IV in 93 patients. An average of 77 points was found using the Lysholm score. CONCLUSION: The results 13.5 years after ACL plasty using a carbon prosthesis are unsatisfactory concerning joint stability and development of secondary arthrosis. There is a discrepancy between the results of the clinical tests and the subjective complaints of the patients.

Adolescent↗