Biomedical subjects

N Wülker

Publications and source records attributed to N Wülker.

At least 19 recordsLinked to original sources

PubMed2006

K-wire transfixation or distraction following the Keller-Brandes arthroplasty in Hallux rigidus and Hallux valgus?

A total of 118 feet with Hallux valgus and Hallux rigidus treated by the Keller-Brandes method were re-examined clinically and radiologically after 9.1 years (range: 1.7-24.3). Correction of the Hallux valgus angle was obtained from an average of 40 degrees to 23 degrees in the Hallux valgus group. Improvement in the postoperative range of motion was observed when the aftertreatment consisted of Kirschner-wire distraction instead of an axial Kirschner-wire transfixation. The patients who underwent Keller-Brandes surgery for Hallux valgus had less pain when the aftertreatment was carried out using an axial Kirschner wire, while those operated on for Hallux rigidus had less pain when the aftertreatment consisted of distraction. The percentage of satisfied or very satisfied patients with the cosmetic results of the Keller-Brandes arthroplasty was more than 66.7%. Patients with Hallux valgus and postoperative aftertreatment with Kirschner wire transfixation were the most satisfied patients, while patients with Hallux rigidus were very satisfied with the postoperative distraction. Our good results are comparable to those in other studies and confirm the success of the Keller-Brandes resection arthroplasty in Hallux valgus with osteoarthritis of the first metatarsophalangeal joint in older patients whose demand for movement is less, and in Hallux rigidus in less active older patients.

Arthralgia↗

PubMed2006

[Pigmented villonodular synovitis].

Pigmented villonodular synovitis (PVNS) is a rare, strongly proliferative disease of the lining of thejoint, synovial bursa and tendon (synovial) sheath. If left untreated, it leads to severe destruction of the joint resulting in an early need for endoprosthetic replacement. The clinical signs are unspecific. Using the diagnostic gold standard MRI, the complete extent of PVNS can usually be determined non-invasively. Once histological confirmation has been obtained, radical tumor resection, synovectomy, possibly curettage, and postoperative irradiation must be applied.

Arthroplasty, Replacement, Knee↗

PubMed2006

[Arthrodesis of the first metatarsophalangeal joint].

Arthrodesis of the first metatarsophalangeal joint is a useful technique for the surgical treatment of hallux rigidus, complicated hallux valgus and rheumatoid forefoot deformity, and for revisions following resection arthroplasty or explantation of a prosthesis combined with interposition of a tricortical bone graft. In primary operations, good or excellent results can be achieved in 80-90% of patients. The articular surface and any exostoses or osteophytes are first resected aiming for a 15-30 degrees extension of the metatarsophalangeal angle and a 5-15 degrees valgus angle. Pseudarthroses occur in 10-13% of arthrodeses stabilized with screws or k-wires. When using a plate for fixation, the rate of pseudarthroses is below 6%. Only a small number of pseudarthroses require revision surgery. Up to 15% of patients develop mostly asymptomatic degeneration of the interphalangeal joint of the hallux.

Arthrodesis↗

PubMed2005

[Metatarsal osteotomies for hallux valgus].

In the surgical treatment of hallux valgus, proximal, diaphyseal, and distal osteotomies of the first metatarsal bone are commonly used. In an overview article different procedures are described as well as our own stage-adapted concept. Deformities with congruent articulation of the metatarsophalangeal joint are successfully treated with a distal chevron osteotomy. In an incongruent joint a distal soft tissue procedure is required for reduction of the joint. The metatarsus varus displacement is corrected with a proximal osteotomy of the first metatarsal bone. The indications and details of the surgical techniques are described as well as postoperative treatment, results, and possible complications.

Follow-Up Studies↗

PubMed2004

["Hallux rigidus"--a global problem?].

The diagnosis "hallux rigidus" is used for limitation of great toe motion, which is particularly painful at push-off during gait. The underlying condition is often degenerative arthrosis of the first metatarsophalangeal joint. Radiographs show no abnormality initially, later degeneration sets in at the dorsal aspect of the joint. Conservative treatment mainly consists of local anti-inflammatory applications and orthopaedic appliances to decrease load at the metatarsophalangeal joint. With progression of the arthrosis, joint preserving procedures such as cheilectomy are used. With this technique, the degenerated dorsal part of the first metatarsal head is resected. In complete destruction of the joint space, arthrodesis is the technique of choice in the mostly active, younger patients. Resection arthroplasty is a simple technique which is used in elderly, less active patients. The results of first metatarsophalangeal joint replacement are inferior to arthrodesis.

Adult↗

PubMed2003

[Influence of the posterior tibial tendon on the medial arch of the foot: an in vitro kinetic and kinematic study].

INTRODUCTION: The respective contributions of the active and passive structures of the foot to the stability of the medical arch were investigated using an in vitro kinetic and kinematic model. The effect of the tibialis posterior tendon on foot and ankle movements, and plantar pressure distribution of the foot were tested in a cadaveric human foot. METHOD: The stance phase from heel-contact to toe-off of normal walking gait and after tibialis posterior tendon rupture was simulated in eight roentenographically normal human feet (age 66 +/- 19 years, males). Ground reaction force and tibial inclination was simulated by means of a tilting angle and force-controlled translation stage. Plantar pressure was measured using a pressure-measuring platform. The force developed by the flexors and extensor muscles of the foot were simulated via cables attached to 7 force-controlled hydraulic cylinders. Tibial rotation was produced by an electric servo-motor, and foot movements measured with an ultrasonic analysis system. RESULTS: The model was verified against the plantar distribution and kinematics of healthy subjects measured during normal gait. Tibialis posterior deficit did not result in any detectable changes in pressure or force-time integral in the medial regions of the foot--a common sign of flat foot (pressure: midfoot 0.2 < or = 0.9; medial forefoot 0.5 < or = p < or = 0.9; hallux 0.5 < or = p < or = 0.9; force-time integral: midfoot p = 0-871; medial forefoot p = 0.632; hallux p = 0.068). Only small tendential changes in the kinematics of the talus and calcaneus were observed in dorsiflexion (0-58 sec; talus 0.1 < or = p < or = 0.6; calcaneus 0.4 < or = p < or = 0.06) and eversion (talus: 0-60 sec. 0.1 < or = p < or = 0.6; calcaneus: 37-60 sec. 0.2 < or = p < or = 0.7). CONCLUSION: The results of this in vitro study show that defective tibialis posterior alone does not produce significant changes in the kinetics or kinematics of the stance phase of normal gait. This suggests that the development of flat foot observed in degeneration of the tibialis posterior tendon occurs only after fatigue of the passive structures of the foot.

Adult↗

PubMed2003

[Forefoot deformities].

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Arthrodesis↗

PubMed2001

[100 years shoulder and elbow surgery].

Within the past 100 years, shoulder and elbow surgery has developed into a highly sophisticated specialty. Technical advancements now allow operative treatment of most shoulder and elbow disorders. Shoulder arthroplasty is able to accurately reproduce normal anatomy and function. It is used in degenerative omarthrosis, humeral head fractures, rheumatoid arthritis, and rotator cuff arthropathy. After 10 years, survival of 93% can be expected and in omarthrosis an outcome score of 85 of 100 points. In recurrent shoulder instability, open surgery is still the gold standard. It allows to accurately adjust capsular tension. Modern arthroscopic techniques shorten the capsule with sutures or by capsular shrinkage, but sufficient follow-up is not yet available. Arthroscopic subacromial decompression is the standard procedure for subacromial disorders. The indication for operative rotator cuff closure must be adjusted to the age and functional expectations of the patient. Smaller defects can be closed arthroscopically. The operative technique in proximal humerus fractures is particularly demanding, due to osteoporosis and the risk of avascular necrosis. Magnetic resonance imaging is the preferred imaging technique at the shoulder, often combined with intravenous or intra-articular contrast injection. Elbow joint replacement is mostly used in rheumatoid arthritis and has achieved a high technical standard.

Arthroscopy↗

PubMed2001

[MRI in dislocation and instability of the shoulder joint].

The value of magnetic resonance imaging (MRI) in shoulder instability depends on its ability to demonstrate pathologic lesions within the joint. Traumatic dislocation in particular often results in capsulo-labral-avulsion, stretching of the joint capsule and impression fracture at the humeral head. Various MR weightings, including spin echo and gradient echo, are useful at the shoulder. A surface coil should be used. Image planes are oriented at the scapula. A capsulo-labral-avulsion can not be reliably demonstrated on non-contrast imaging in the absence of intra-articular effusion. With indirect arthrography, gadolinium is intravenously injected and enhances the articular space. With direct arthrography, gadolinium or saline are injected into the joint, optimising the demonstration of labral lesions. In grade I lesions, fluid enters the lesion without deformation or detachment of the labrum. In grade II lesions, the labrum is of abnormal size or shape, but still attached to the glenoid. In grade III lesions, the labrum is completely detached. Sensitivity of magnetic resonance arthrography for labral lesions is 90% and specificity is 95%. Impression fractures at the humeral head are well demonstrated but avulsion fractures at the glenoid are not. Lesions at the joint capsule cannot be seen. Decisions relating to shoulder instability are primarily based on patient history and physical examination. MRI adds valuable information, particular in unclear clinical settings.

Acute Disease↗

PubMed2001

[Muscle efficiency in total shoulder prosthesis implantation: dependence on position of the humeral head and rotator cuff function].

Modern shoulder prostheses permit an anatomic reconstruction of the joint, although the biomechanical advantages are not proven. The goal of this study was to investigate the relationship between position of the humeral head and function of the shoulder prosthesis (muscle efficiency). Shoulder elevation-motion and rotator cuff defects were simulated in vitro in a robot-assisted shoulder simulator. The EPOCA Custom Offset shoulder prosthesis (Argomedical AG, Cham, CH) was implanted in seven normal shoulders (77 +/- 20 kg, 55 +/- 14 years). Active elevation was simulated by hydraulic cylinders, and scapulothoratic motion by a specially programmed industrial robot. Muscle efficiency (elevation-angle/muscle-force of the deltoid muscle) was measured in anatomic (ANA), medialised (MED) and lateralised (LAT) positions of the humeral head, with or without rotator cuff muscle deficiency. Medialisation increased efficiency by 0.03 +/- 0.04 deg/N (p = 0.022), lateralisation decreased it by 0.04 +/- 0.06 deg/N (p = 0.009). Supraspinatus muscle deficiency increased the deltoid force required to elevate the arm, and thus decreased efficiency (ANA p = 0.091, MED p = 0.018, LAT p = 0.028). The data confirm that the position of the humeral head affects the mechanics of total shoulder arthroplasty. Medialisation increases efficiency of the deltoid muscle and may prove useful in compensating isolated supraspinatus muscle deficiency. Lateralisation, in contrast, leads to an unfavorable situation.

Adult↗

PubMed2000

The effect of negative intraarticular pressure and rotator cuff force on glenohumeral translation during simulated active elevation.

OBJECTIVE: The objective of this study was to determine the effect of negative pressure in the intraarticular space and subacromial bursa, as well as rotator cuff force, on glenohumeral translation during active elevation. DESIGN: Glenohumeral translation during elevation in the scapular plane was measured under greater than, less than, and equal to physiologic rotator cuff muscle force, as well as with and without the subacromial bursa and intraarticular space vented. BACKGROUND: Negative intraarticular pressure has been shown to help stabilize the glenohumeral joint in passive motion, although the effect on translation during active motion has not been investigated. METHODS: Eight cadaverous human shoulder specimens were tested in a dynamic shoulder simulator. Forces in the muscles of the rotator as well as the middle deltoid muscle were simulated using servohydraulic cylinders. Joint motion was measured using an ultrasonic motion analysis system. RESULTS: Superior translation of the humerus increased 1.2 mm (SD, 0.4) upon venting of the bursa, and 2.1 mm (SD, 1.7) upon venting of the joint capsule at 25 degrees of glenohumeral elevation in the scapular plane. At 90 degrees elevation, venting the bursa did not change superior translation but increased anterior translation 1.04 mm (SD, 1.0). Venting of the joint capsule increased superior translation by 2.8 mm (SD, 2.5). Decreasing rotator cuff force increased superior translation, while reducing it did not. CONCLUSION: The muscles of the rotator cuff and the negative pressure of the intraarticular space and the subacromial bursa stabilize the glenohumeral joint since they restrict translation in the superior and anterior directions. RelevanceIncreased glenohumeral translation and the resulting asymmetric loading may lead to arthrosis and ultimately rotator cuff arthropathy.

Adult↗

PubMed2000

Hindfoot motion after isolated and combined arthrodeses: measurements in anatomic specimens.

Passive motions at the subtalar joint, talonavicular joint and calcaneocuboid joint were measured in eight ankle specimens, using an ultrasonic motion analysis system. Arthrodeses of the three joints were performed in all feasible combinations and the resulting motion change at the unfused joints was determined. Motion at the subtalar joint was not significantly affected by fusion of the calcaneocuboid joint, reduced to one quarter by fusion of the talonavicular and calcaneocuboid joints (double arthrodesis) and almost completely eliminated with all other fusions. Motion at the talonavicular joint was not significantly affected by calcaneocuboid fusion and reduced to approximately one third with the subtalar and the double arthrodesis. Motion at the calcaneocuboid joint was not significantly reduced by subtalar fusion but almost completely eliminated in all fusions involving the talonavicular joint. It is concluded that the talonavicular joint is the key articulation for hindfoot motion. Double arthrodesis preserved significant motion at the subtalar joint. Fusion of the calcaneocuboid joint had no significant influence on remaining hindfoot motion.

Adult↗

PubMed2000

[Omarthrosis].

Degenerative arthrosis of the shoulder is less commonly diagnosed than at the joints of the lower extremity. The shoulder joint does not bear weight and some of the mechanical stresses are taken up by the subacromial space. However, anatomical studies reveal a significant incidence of degenerative changes at the glenohumeral joint with increasing age. Arthrosis is caused by mechanical loading, rotator cuff defects, and abnormal joint motion following surgery. Clinical symptoms are rarely focused on the glenohumeral joint. Clinical findings are also unspecific. Rotation of the elevated arm with compression of the joint is a reliable sign of arthrosis. The diagnosis is made with anteroposterior and axial radiographs. Ultrasonography should always be performed and computed tomography only in specific cases. Nonoperative treatment includes analgesic and antiphlogistic medication, motion therapy, and muscle exercises. Shoulder arthroplasty is favoured in advanced arthrosis. New prostheses are intended to reconstruct the normal anatomy as closely as possible.

Humans↗

PubMed1999

[Lateral ankle ligament rupture. When is surgical management indicated and when conservative therapy preferred?].

In lateral ankle ligament tears, the anterior talofibular ligament ruptures most commonly, often in conjunction with the calcaneofibular ligament. The posterior talofibular ligament is rarely affected. Associated injuries at the adjacent ligamentous structures or at the articular cartilage of the ankle commonly occur. The diagnosis is established clinically with the anterolateral drawer sign and an increased lateral talar tilt. Stress radiographs in two planes demonstrate talar tilt and anterior displacement of the talus, in comparison to the unaffected side. Magnetic resonance imaging provides an early diagnosis of concomitant injuries. Simple, acute lateral ankle ligament tears are treated non-operatively. Surgery is indicated in dislocated bone avulsions and in chondral or osteochondral fractures. A recurrent tear in an athletic patient should also be treated operatively. Athletic endeavours, the number of torn ligaments and patient age are no useful indicators for surgical treatment. Conservative treatment consist of oedema therapy, immobilization of the fibular ligaments with as little compromise of ankle joint function as possible, and rehabilitation with muscle strengthening and proprioception training. During surgery, the ligament stumps are reapproximated in anatomic position, reinforced with local tissue if necessary, and the articular surface is examined for concomitant injuries.

Adolescent↗

PubMed1998

[Not Available].

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Journal Article↗

PubMed1998

Follow-up results 17 years after resection arthroplasty of the great toe.

Resection arthroplasty of the first metatarsophalangeal joint is a well-known operation. The follow-up results more than 17 years after arthroplasty for hallux valgus are reported and discussed. Between 1971 and 1980, 335 resection arthroplasties were performed on 205 patients. The sole indication for resection arthroplasty of the great toe in this study was hallux valgus. The technique involved removal of the proximal one-third of the phalanx with interposition of a capsular flap, occasionally including temporary Kirschner wire fixation. After 17.6 years on average, 102 patients were re-examined clinically and radiographically. Questionnaire assessment revealed a significantly prolonged walking distance, and 70% of the patients were pain-free at follow-up investigation, whereas 67% suffered from severe pain before the operation. Clinical evaluation showed diminished weight-bearing of the great toe during walking and a reduced range of motion of the resected first metatarsophalangeal joint. Radiographic shortening of the proximal phalanx was 37%. The average hallux valgus angle was 23 degrees at follow-up and 34 degrees prior to surgery. The unacceptably high rate of hallux valgus relapse, especially due to a high intermetatarsal angle, emphasizes the unsatisfactory long-term results of the resection arthroplasty. We now recommend this operation for older patients only, and a differentiated approach using reconstructive procedures according to the clinical and radiographical situation for younger patients.

Adolescent↗

PubMed1997

[High definition roentgen technique. Alternative to or improvement of conventional roentgen technique].

X-ray images were taken of 22 patients suffering from different orthopaedic disease patterns using magnification with focus diameters between 0.012 and 0.100 mm. This yielded improved resolution of detailed structures, especially in tumours and aseptic bone necroses. Owing to the relatively low efficiency of the X-ray tube (affected by the condition of the X-ray equipment), however, exposure times of several seconds were required, and the voltage had to be higher than in a conventional X-ray procedure. This resulted in a lack of sharpness owing to movement and a loss of contrast. Hence, the clinical use of focus diameters below 0.1 mm does not seem to be meaningful.

Bone Diseases↗

PubMed1997

Reconstruction of the lateral ligaments of the ankle using a regional periosteal flap.

We have treated 94 patients with chronic instability of the lateral side of the ankle by reconstruction of the ligaments with local periosteal tissue. We reviewed 90 cases after a mean follow-up of 2.8 years (2 to 9) using a questionnaire, clinical examination and radiography. The results on a 100-point ankle score indicated that 81% had a good or excellent result. The periosteal flap-replacement technique allows anatomical reconstruction and does not sacrifice other ligaments or tendons in the foot.

Adolescent↗