Biomedical subjects

J Zeichen

Publications and source records attributed to J Zeichen.

32 records · Page 2Linked to original sources

PubMed2001

Cyclic mechanical stretching modulates secretion pattern of growth factors in human tendon fibroblasts.

The objective of the study was to investigate whether the response profile of the growth factor of human tendon fibroblasts could be beneficially influenced through the application of mechanical stretch. It was considered that this would elucidate structural and functional problems, often seen after tendon and ligament healing. The secretion pattern of transforming growth factor-beta (TGF-beta), platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) was determined in mechanically stretched fibroblasts and compared to non-stretched controls. Human tendon fibroblasts were experimentally stretched for 15 and 60 mm at a frequency of 1 Hz and an amplitude of 5%. The secretion of TGF-beta PDGF and bFGF was measured by enzyme-linked immuno-sorbent assay. All the growth factors investigated were indeed secreted by human tendon fibroblasts both in stretched cells and controls. Mechanical stretch increased the secretion pattern of the growth factors. The increased concentrations of TGF-beta bFGF and PDGF after cyclical mechanical stretching may have a positive influence on tendon and ligament healing through stimulation of cell proliferation, differentiation and matrix formation.

Adult↗

PubMed2000

[Expression of type VI collagen in arthrofibrosis. An immunohistochemical study].

Arthrofibrosis is a disabling complication after trauma and surgery due to massive connective tissue proliferation. The etiology and pathogenesis have never been fully understood. A strong immune response may lead to activation and proliferation of fibroblasts with excessive and disordered deposition of matrix proteins. In similar pathological conditions, like lung fibrosis or superficial fibromatoses with fibrotic transformation an increased expression of collagen type VI has been reported. We investigated fibrotic tissue samples taken from 18 patients (average age: 32.7 years), who underwent arthrolysis of the knee joint because of symptomatic arthrofibrosis following ligament injury. The mean interval between trauma and arthrolysis was 13.8 months (range 4-50 months). Tissue samples were taken from the infrapatellar fat pad and intercondylar connective tissue. All samples were stained with HE. The expression of type III and VI collagen was studied immunohistochemically using an immunoperoxidase method for light microscopic visualization. Histologic analysis from patients with arthrofibrosis showed a synovial hyperplasia with cell infiltration and vascular proliferation compared to synovial tissue samples from knee joints without any detectable pathology. Subsynovial an increased deposition of matrix proteins was visible. Type VI collagen was widely distributed as a network subsynovial and around capillary walls. Type III collagen showed a diffuse distribution. Arthrofibrotic tissue is, similar to pathological conditions with fibrotic transformation characterized by an increased expression of collagen type VI. Collagen type VI may play an important role in matrix homeostasis. It serves as an anchoring element between collagen fibers and as a cell binding structure.

Adolescent↗

PubMed2000

[Proprioception after reconstruction of the anterior cruciate ligament. Endoscopic vs. 2 tunnel technique].

ACL reconstruction with patellar tendon autograft is a standard procedure which can be performed arthroscopically with a femoral half tunnel drilled from the joint or using the two-tunnel technique with medial miniarthrotomy and additional femoral approach. The arthroscopic procedure with single incision was supposed to increase stability and to improve proprioception by earlier rehabilitation. 29 patients with ACL deficiency were included in the study. 15 patients were treated endoscopically, 14 patients by using the two-tunnel technique. Proprioception, Lysholm and Tegner scores as well as stability (KT-1000) were assessed preoperatively, 3 and 6 months postoperatively. A deficit of proprioception was assessed in either group preoperatively, which could be improved after 3 months only in the arthroscopic group. 6 months postoperatively, either group showed a restitution of proprioception near full extension and full flexion of the knee. In the mid range position, the proprioception could not be restored. There were no differences in stability and the Lysholm and Tegner scores between the groups after 6 months postoperatively. The comparison between the patients with acute and chronic instability shows a better proprioception in the acute group in the mid range position 6 months after the reconstruction.

Adult↗

PubMed2000

Outcome analysis following open rotator cuff repair. Early effectiveness validated using four different shoulder assessment scales.

Evaluation of upper extremity function after reconstructive surgery is increasingly important both to predict outcome and for the control of cost-effectiveness. Three validated, self-administered shoulder questionnaires were applied prospectively in 23 otherwise healthy patients with rotator cuff deficiency and correlated to the Constant-Murley Shoulder Score and a visual analogue scale for satisfaction. Seven women and 16 men with combined tears of supraspinatus and infraspinatus (mean age 55.3 +/- 10.5 years, r/l: 14/9, follow-up 57.8 +/- 15.7 weeks) were gathered prospectively and evaluated pre- and postoperatively with the American Shoulder and Elbow Surgeons (ASES) Shoulder Index, the Simple Shoulder Test (SST) and the Disabilities of the Arm, Shoulder and Hand Module (DASH questionnaire). Additionally, a visual analogue scale for satisfaction was employed. All four scores and the visual analogue scale revealed improvement at a statistically significant level (P < 0.01) after surgery. All questionnaires showed a significant correlation with the Constant-Murley Shoulder Score (ASES: r = 0.871, P < 0.01; DASH: r = -0.758, P < 0.01, SST: r = 0.494, P < 0.05, Pearson's correlation coefficient). Taken together, all questionnaires were easy to apply, and reliable evaluation of shoulder function was possible with significant correlation to the Constant-Murley Shoulder Score postoperatively. The SST was easy to apply, and compound outcome analysis was possible with the ASES Shoulder Index and DASH questionnaire. The DASH scale was the most complex evaluation instrument. The Constant-Murley Shoulder Score comprises a physical examination, which is advantageous but restricts the application to the office. For postoperative assessment without the patient having to return to the clinic, the ASES Shoulder Index is preferred because of its good correlation to the Constant-Murley Shoulder Score (r = 0.871) and the visual analogue scale for satisfaction (r = 0.762).

Adult↗

PubMed2000

Proprioception after rehabilitation and reconstruction in knees with deficiency of the anterior cruciate ligament: a prospective, longitudinal study.

We assessed proprioception in the knee using the angle reproduction test in 20 healthy volunteers, ten patients with acute anterior instability and 20 patients with chronic anterior instability after reconstruction of the anterior cruciate ligament (ACL). In addition, the Lysholm-knee score, ligament laxity and patient satisfaction were determined. Acute trauma causes extensive damage to proprioception which is not restored by rehabilitation alone. Three months after operation, there remained a slight decrease in proprioception compared with the preoperative recordings, but six months after reconstruction, restoration of proprioception was seen near full extension and full flexion. In the mid-range position, proprioception was not restored. At follow-up, 3.7 +/- 0.3 years after reconstruction, there was further improvement of proprioception in the mid-range position. There was no difference between open and arthroscopic techniques. The highest correlation was found between proprioception and patient satisfaction. After reconstruction of the ACL reduced proprioception may explain the poor functional outcome in some patients, despite restoration of mechanical stability.

Activities of Daily Living↗

PubMed1999

[Os trigonum syndrome].

The os trigonum syndrome is an entity causing posterior ankle pain and occurs mostly with typical sports activities. Diagnosis and differential diagnosis are presented. Typical complaints and therapeutic procedure are demonstrated in one case. Therapy includes different non-operative methods, resistance to non-operative procedures is an indication for excision of this ossicle.

Adolescent↗

PubMed1999

[Augmented tenoplasty in a case of tibialis anterior tendon rupture].

A tendon transfer or interposition tendon graft is usually recommended for treatment of late diagnosed ruptures of the tibial anterior tendon. A new operative technique using augmented tenoplasty is described in one patient. After 3 years the patient was asymptomatic and showed normalized function. The operative method has the advantage of no additional loss of function in comparison with other methods.

Adult↗

PubMed1999

Medium-term results of the operative treatment of recurrent patellar dislocation by Insall proximal realignment.

Between 1984 and 1991, 36 patients with the diagnosis of recurrent patellar dislocation were treated operatively using the proximal realignment procedure. Thirty patients were available for follow-up. The average follow-up period was 6.3 years (range 2-9.6 years). The average age at injury was 21.3 years with a predominance of female patients. At follow-up all knees were physically examined. The results were evaluated using the score of Larsen and Lauridsen as well as the Tegner score and subjective assessment. Radiographs from 19 patients (63%) were available for review. At follow-up one patient suffered from a recurrence of patellar dislocation. All patients had stable knee joints and a full range of motion. There was no statistically significant difference between pre- and postoperative sports activity level. Seven patients (23.3%) had excellent results, 12 patients (39.9%) good results and 1 a poor result using the Larsen and Lauridsen score. Subjective assessment revealed the operative result as very good, good or satisfactory in 90%. Patellofemoral osteoarthritis was seen in 7 of 19 patients (36.8%). With a proximal realignment procedure good clinical results can be achieved for recurrent patellar dislocation. Subjective satisfaction with this procedure is rated as good. It is successful in preventing redislocation.

Adolescent↗

PubMed1999

Immunohistochemical localization of collagen VI in arthrofibrosis.

Arthrofibrosis is a disabling complication after knee trauma and surgery. Clinically, it is characterized by pain and joint stiffness due to massive connective tissue proliferation. In similar pathological conditions with fibrotic transformation such as lung fibrosis or superficial fibromatoses, an increased expression of collagen type VI has been reported. Collagen VI, which forms a filamentous network, is thought to serve as an anchoring element between collagen I/III fibrils and basement membranes and as a cell binding structure. Collagen VI may also play a contributing role in the pathogenesis of arthrofibrosis. The aim of the present study was therefore to demonstrate the localization and distribution of type VI collagen in arthrofibrotic tissue. Tissue samples from the infrapatellar fat pad and intercondylar synovia of 13 patients suffering from arthrofibrosis were taken at surgery. The expression of type VI collagen was studied immunohistochemically using an immunoperoxidase method for light microscopic visualization. Histologic analysis showed a synovial hyperplasia with inflammatory cell infiltration and vascular proliferation. Compared with normal synovial tissue, type VI collagen was widely distributed as a network subsynovially and around the capillary walls. The results of the present study suggest that dysregulation of collagen VI synthesis could be an important contributing factor in the complex mechanisms of disordered matrix protein deposition leading to arthrofibrosis.

Adolescent↗

PubMed1998

[Interim results of surgical therapy of patellar dislocation by Insall proximal reconstruction].

Between 1984 and 1991, 57 patients with diagnosis of an acute or recurrent patellar dislocation were treated operatively using proximal realignment with vastus medialis transfer and lateral release (Insall operation). A total of 45 patients (15 with acute and 30 with recurrent patellar dislocation) were reviewed at an average follow-up of 6.5 years (2-9.6 years). The average age at injury was 21.5 years, with a predominance of female patients. Follow-up examination included routine knee examination, clinical review using the modified knee scoring scale of Larsen and Lauridsen, sports activity level and subjective satisfaction. Radiographics from 27 patients (60%) were evaluated. One patient from each group suffered recurrence of patellar dislocation. All patients had stable knee joints and a full range of motion. There was no statistical difference in the pre- and postoperative sports activity level in both groups. Three patients (19.9%) with acute patellar dislocation and seven patients (23.3%) with recurrent patella dislocation had excellent results using the Larsen and Lauridsen score scale. Ten patients (66.6%) with acute and 12 (39.9%) with recurrent dislocation had good results. One patient with recurrent patellar dislocation had a fair result. Subjective evaluation revealed the operative result in 93% of cases as very good, good or satisfactory. Patellofemoral osteoarthritis was seen in 11 (40.7%) of 27 patients. Our results show good clinical results for the treatment of acute patellar dislocation in young, active patients with the proximal realignment procedure. The recurrence rate of patellar dislocation can be reduced for acute and recurrent patellar dislocation. Subjective satisfaction with this procedure is rated very good.

Acute Disease↗

PubMed1998

[Intrinsic properties of arthrofibrosis tissue: histologic and cell biology analysis].

A chronic inflammatory reaction and an increased expression of Ki-67 positive cells in arthrofibrotic tissue and the increased proliferation of fibroblasts from arthrofibrotic tissue could be due to an immunopathological reaction. Compared to systemic and organ fibrotic tissue arthrofibrotic tissue is characterized by an increased expression of collagen type VI.

Adolescent↗

PubMed1997

One- versus two-incision technique for anterior cruciate ligament reconstruction with patellar tendon graft. Results on early rehabilitation and stability.

Anterior cruciate ligament (ACL) reconstruction with patellar tendon graft has become a standard procedure. The graft can be inserted either using two tunnels and a lateral femoral incision or with a femoral half-tunnel drilled from the joint, thus avoiding the lateral incision. Advantages have been claimed for the single-incision technique in the early rehabilitation period. Forty patients with ACL deficiency were included in a prospective randomized trial comparing the single- and two-incision technique with a follow-up period of 12 months. Preoperative data did not show any significant difference between the two groups. At early follow-up no differences were observed with respect to complications or the progress of rehabilitation. Evaluation at 12 months postoperatively using the IKDC form revealed good to excellent results in 70% of patients. ACL reconstruction reduced anterior translation of the knee significantly at the 6-month and 12-month follow-up with a slight increase of MMD values at 12 months in both groups. The arthroscopic single-incision technique did not differ from the mini-open technique in terms of postoperative pain medication, incidence of effusion, postoperative range-of-motion or any rehabilitation parameters. Stability was comparable in both groups at all time periods. We conclude that an arthroscopic single-incision technique has no advantage over a mini-open two-incision technique for ACL reconstruction with patellar tendon graft in terms of subjective or objective parameters.

Adult↗

PubMed1995

[Results of follow-up of surgical treatment of complicated acetabulum fractures with extended approaches].

Extended approaches are indicated for complex acetabular fractures. The advantage of extended approaches is the simultaneous exposure of both columns of the acetabulum; disadvantages are the wide exposure of the soft tissue and a high rate of heterotopic ossification. Muscle weakness and necrosis of the muscle have been described. Although there is good exposure with an extended approach, the indication for it is restricted. Between 1972 and 1993, 688 patients with acetabular fractures were treated at the Trauma Department of the Hannover Medical School; 322 had open reduction and internal fixation. Thirty-five patients (10%) were treated with an extended approach. In a retrospective study of 24 patients treated with an extended approach between 1985 and 1993, perioperative data, long-term clinical outcome and radiological outcome were investigated. The aim of the study was to compare the outcome of two groups treated using either the classical extended iliofemoral approach or the Maryland modification. Eleven patients were treated with the extended iliofemoral approach, 13 with the Maryland approach. There were no significant differences in age, type of accident, fracture classification, time to operation, time of operation and blood loss. The postoperative X-ray was anatomic or nearly anatomic in 22 cases; 2 patients had a dislocation of more than 2 mm. The main complications were hematomas and seromas. In both groups we found one thrombosis and one nerve injury with partial recovery. Twenty patients were followed up at least 2 years after trauma, 8 after extended iliofemoral approach and 12 after Maryland approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetabulum↗

PubMedDate not supplied

The proliferative response of isolated human tendon fibroblasts to cyclic biaxial mechanical strain.

At the cellular level, dynamic strain plays a key role in cell stimulation and organization of the extracellular matrix. Although positive effects of physical strain on tendon tissue are well known, little knowledge exists on how mechanical strain affects tendon cells. In this study, human tendon fibroblasts from patellar tendon were cultured on silicone dishes. Subsequently, cyclic biaxial mechanical strain was applied to the dishes for 15, 30, and 60 minutes using a specially developed cell stretching system. After the fibroblasts were strained, cells were tested for proliferation at 6, 12, and 24 hours. As a control, cells were grown on silicone dishes but did not receive any strain. A biphasic response in proliferation was observed for the 15- and 60-minute strain periods: at 6 hours and 24 hours there was more proliferation than at 12 hours. After a strain duration time of 30 minutes, a lower proliferation rate was measured compared with control levels. This study shows that application of mechanical stress to tendon fibroblasts resulted in an alteration of cellular proliferation depending on the stress time. Our results may implicate future modifications in the treatment of ligament and tendon injuries.

Adult↗