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Biomedical subjects

C J Wirth

Publications and source records attributed to C J Wirth.

At least 37 records · Page 2Linked to original sources
PubMed2003

[Arthroscopy of the hip].

Arthroscopy of the hip has become a well-established procedure for minimally invasive therapy of hip disorders. The surgical technique is demanding. A fracture table for distraction of the joint is required, as well as an exact positioning technique is most important. Because of eh great distance between skin and joint only restrictive intrarticular maneuvers are possible. Arthroscopically the hip can be divided into a central and peripheral compartment. For arthroscopy of the central compartment distraction of the joint is necessary. This part comprises the loaded surface of the femoral head and the lunate cartilage. The peripheral compartment consists of the unloaded cartilage of the femoral head and the femoral neck until the capsular insertion. This compartment can be visualized without traction. Good results can be achieved in the therapy of labral lesions, loose bodies, moderate osteoarthritis, synovial diseases and pathology of the teres ligament. Performing hip arthroscopy in an adequate technique and under consideration of contraindications, complications are rare.

Arthroplasty, Replacement, Hip↗
PubMed2003

[Arthroscopic anterior shoulder stabilization combined with laser-assisted capsular shrinkage (LACS) compared to other procedures].

INTRODUCTION: Does additional laser assisted capsular shrinkage (LACS) help to reduce the recurrence rate in arthroscopic anterior shoulder stabilization? METHODS: In a prospective study from 7/97 to 4/99 at 22 nonselected patients a combined Caspari + LACS-technique was performed. We could follow-up 152 (80%) of a total 191 anterior shoulder stabilizations between 4/88 and 4/99 (124 male, 28 female, average age 33 years) (80(52%) Bankart, 30(20%) Du Toit/Roux, 20(13%) Caspari, 22(15%) Caspari + -LACS. RESULTS: The rate of dislocation was 7% (11/152) for all patients (Bankart 5% 4/80), Du Toit/Roux 4% (1/30), Caspari 25%(5/20), Caspari + LACS 5%(1/22)). Using the score of Rowe et al. [34] 113 patients (75%) rated excellent or good (Bankart 77%, Du Toit/Roux 83%, Caspari 60%, Caspari + LACS 86%). CONCLUSIONS: An additional laser capsular shrinkage helps to reduce the high rates of dislocation in arthroscopic anterior shoulder stabilization with results similar to standard open procedures.

Adult↗
PubMed2002

[Pattern of paralysis and reconstructive operations after traumatic brachial plexus lesions].

The aim of this study was to evaluate persistent patterns of paralysis after traumatic brachial plexus lesions. As a result, consecutive reconstructive operations according to our differential therapy concept are presented. Between 04/1994 and 12/2000 in 104 patients with brachial plexus palsy, the grade of muscle power of the affected upper extremities was evaluated prospectively. The neuromuscular patterns of defect showed, in most cases, insufficient muscle power grades of 0-2 for the deltoid muscle (90%), supraspinatus muscle (82%), infraspinatus muscle (93%), elbow flexors (67% to 77%), hand and finger extensors (69% to 71%), and the abductor and extensors of the thumb (67% to 70%). In corresponding frequency, the following operations were performed between 04/1994 and 06/2002: shoulder arthrodesis (n 26), trapezius transfer (n 80), rotation osteotomy of humerus (n 10), triceps to biceps transposition (n 11), transposition of forearm flexors or extensors/Steindler operation (n 12), latissimus transfer (n 7), pectoralis transfer (n 1), teres major transfer (n 1), transposition of forearm flexors to the tendons of extensor digitorum (n 19) and of the extensor pollicis longus (n 9), and wrist arthrodesis (n 5). On malfunction of muscles following brachial plexus lesions, taking into account the individual neuromuscular defect, passive joint function, and bony deformities, different procedures such as muscle transposition, arthrodesis, and corrective osteotomy can be performed to improve function of the upper extremity.

Adolescent↗
PubMed2002

Relative motion of a mobile bearing inlay after total knee arthroplasty--dynamic in vitro study.

OBJECTIVE: The purpose of this study was to measure the in vitro range of motion of a mobile bearing inlay knee prosthesis under dynamic isokinetic loading conditions. Additionally, the effect on the range of motion of rotational malalignment of the tibia baseplate was determined. DESIGN: Specimens with implanted knee prostheses were mounted onto a custom built knee simulator. 3-D inlay movement was measured by an ultrasonic tracking system. BACKGROUND: More recent knee prostheses include mobile bearing inlays type designs. These systems are intended to allow higher conformity of the tibiofemoral joint and thereby decrease contact stress without decreasing the knee's range of motion. METHODS: Dynamic testing in the knee simulator mimicked both the speed and resulting moment of a knee isokinetic extension test. The tibia baseplate was first implanted with no rotational malalignment, followed by sequential internal and external rotation of upto 15 degrees. RESULTS: Correctly aligned, the inlay center moved 3.5 mm (SD, 1.5 mm) posterior during extension. With the tibia baseplate externally rotated more than 10 degrees the movement pattern changed. CONCLUSION: At up to 10 degrees of rotational malalignment the primary motion pattern of the mobile bearing is maintained. However, beyond 10 degrees unintended motion may occur. RELEVANCE: These test results correlate to radiographic measurements of in vivo movements of mobile bearing inlays showing "paradoxical" movement of the mobile inlay compared to physiologic meniscal movement.

Biomechanical Phenomena↗
PubMed2001

High tibial osteotomy versus unicompartmental joint replacement in unicompartmental knee joint osteoarthritis: 7-10-year follow-up prospective randomised study.

The clinical outcome of patients treated either by high tibial osteotomy or unicompartmental arthroplasty for medial unicompartmental osteoarthritis of the knee was compared in a prospective randomised study. In total, 32 patients received a high tibial osteotomy (HTO) and 28 patients a unicompartmental arthroplasty (UKA). More intra- and postoperative complications were observed after HTO. Patients were assessed at an average of 2.5 (1.6-5), 4.5 (3.6-7), and 7.5 years (6.6-10) after the operation. Using the Knee Society Score, 71% (15) of patients after osteotomy and 65% (13) after replacement had a knee score of excellent or good 7-10 years postoperatively. The Kaplan-Meier survival analysis 7-10 years postoperatively showed a survivorship of 77% for UKA and 60% for HTO. Although the unicompartmental prosthesis used in this series has not shown promising results, we conclude that with the advanced design of unicompartmental prosthesis today, UKA offers better long-term success.

Aged↗
PubMed2001

[Surgical treatment and rehabilitation for improving function of shoulder muscle impairment].

INTRODUCTION: The results of our integrated conservative and operative concept of therapy to compensate insufficient shoulder muscles following brachial plexus palsy or other nerve damages are presented. PATIENTS/METHODS: To improve stability and function of the shoulder in case of deltoid and supraspinatus paralysis 19 patients (3 female; 16 male; average age 37 years, range 17 to 61 years) underwent a shoulder arthrodesis. In 69 patients (12 female; 57 male; average age 31 years, range 19 to 69 years) a trapezius transfer was performed. The indication for a rotation osteotomy of the humerus to improve loss of external rotation due to paralytic infraspinatus muscle was determined in 5 male patients (average age 30 years, range 15 to 42 years). Our results are based upon an average follow-up of 21 (6-70) months after shoulder fusion, 21 (2-68) months after trapezius transfer and 28 (3-62) months after rotation osteotomy of the humerus. RESULTS: The trapezius transfer resulted in increased function of abduction of 6.6 degrees to 35.9 degrees (10 degrees-90 degrees) and forward flexion of 12.6 degrees to 30.9 degrees (5 degrees-85 degrees). A more stable condition of multidirectional shoulder instability was experienced by 64 patients (92.8%), and 65 patients (94.2%) were subjectively satisfied with the outcome of the operation. The strength and extent of functional improvement was, on average, greater following shoulder arthrodesis: abduction 10.3 degrees to 57.4 degrees (20 degrees-80 degrees), forward flexion of 12.6 degrees to 57.1 degrees (20 degrees-105 degrees). 17 patients (89.5%) were subjectively satisfied with the outcome. Patients who had undergone external rotation osteotomy showed an average deficiency of external rotation of 30 degrees before operation. After osteotomy an improvement of 29 degrees to 3 degrees external rotation was achieved. All patients were satisfied with the increase of function. CONCLUSIONS: In patients with failed shoulder muscles, particularly after brachial plexus palsy, secondary operations according to the individual pattern of muscle failure result in an improvement of shoulder function and stability, as well as patients' satisfaction. Therefore, adequate conservative treatment before and after reconstructive operations is of great importance.

Adolescent↗
PubMed2000

[Pathology of acute and chronic tendon injuries].

The load limit of a tendon is expressed by the not linear force/lengthening behavior. It is determined by the interrelation between load and load-bearing capacity. The load of a tendon results from exogenous, endogenous and temporal factors. The property factors and the aging influence the load-bearing capacity of a tendon. Partial ruptures show necrosis, calcification and fiber swelling. The attachment area shows a mineralization of the cartilage zone, a loss of the collagen fibrils and calcifications. The tendon rupture knows extrinsic and intrinsic causes. Primary are micro and macrovascular tendon alterations, usually favour the rupture of tendons.

Achilles Tendon↗
PubMed2000

[Tendon suture: surgical techniques].

Tendon sutures belong to the bases of surgical activity. Particularly in the last decades these sutures experienced a substantial upswing by the introduction of new techniques and materials. Target is to reestablish the tendon function. In order to achieve this target, it requires knowledge of tendon healing. An outline of suture materials, in particular specific suture techniques as well as the subsequent treatment is given. With different localizations of the tendon lesions one deals.

Humans↗
PubMed2000

[Knee endoprosthesis: biomechanical requirements and consequences].

The experiments described herein permitted the dynamic in vitro measurement of the mechanical efficiency of the quadriceps muscle, both before and after total knee arthroplasty (TKA). The measurement of tibiofemoral pressure on fixed and mobile polyethylene inlays, as well as the movement of mobile inlays, is described. The Interax TKA system was implanted in 8 fresh frozen knee cadavers which were then mounted onto a knee-simulating machine. An isokinetic extension motion was simulated by extending the knee specimens under a constant extension torque of 31 Nm. The quadriceps muscle force required for this motion was not found to increase after implantation of the prostheses. Pressure on the mobile inlay was 60% lower than that measured on the fixed inlay. A 4-mm posterior migration of the mobile inlay on the tibial base plate was observed, with no motion of the inlay femoral component contact surface, which migrated posteriorly in the fixed bearing prosthesis. Thus, instead of moving posteriorly, the mobile inlay femoral component contact area remained at the center of the inlay during the entire extension motion.

Aged↗
PubMed2000

[Knee endoprosthesis: clinical aspects].

Despite improvements in component design, instruments, and operative technique, there remains a significant complication and failure rate in total knee arthroplasty (TKA). Revision TKA accounts for every tenth operation in TKA. From June 1991 to June 1994, 209 TKAs (182 patients) were performed. Of these, 73% were uncemented, 11.2% cemented, and 15.8% hybrid. The patella was resurfaced in 96% with a cemented polyethylene or an uncemented metal-backed patella component. Follow-up showed significant improvement in knee and function scores 1 and 5-7 years postoperatively. Of the patients, 77% showed no general and 80% no local postoperative complications. Overall, 42 revisions (41 patients) were performed during the 7-year follow-up. Revision surgery was necessary because of aseptic loosening (8.1%), polyethylene wear (4.8%), complications of the extensor mechanism (2.4%), traumatic periprosthetic fractures or knee luxation (1.4%), and septic loosening (3.3%). Further improvements of polyethylene will reduce polyethylene wear. Uncemented fixation of this prosthesis can only be recommended with hydroxyapatite coating.

Adult↗
PubMed2000

Triceps to biceps transfer to restore elbow flexion in three patients with brachial plexus palsy.

Between April 1994 and April 1998, triceps to biceps transfers were done for three men with post-traumatic lesions of the brachial plexus and consequent loss of elbow flexion. Their mean age at the time of their accidents was 33 years (range 19-41) and at the time of muscle transfer 40 years (28-46), with a mean observation period of 21 months (12-31). The transfer resulted in active elbow flexion in all patients with a mean of 113 degrees (90 degrees-130 degrees) and a degree of strength 4-5 (contraction against resistance) with no remaining deficit of passive extension. Two patients were satisfied with the result of the operation and the other was content. No complications were noted. The transfer of the triceps muscle to the tendon of the biceps muscle on loss of elbow flexion resulted in adequate movement and degree of strength. The triceps to biceps transfer involves operating close to the elbow joint and minimal complications, is cosmetically satisfactory, and is particularly suitable for co-contraction of triceps and biceps.

Adult↗