Revision nach unikondylärer Knieprothese

Unicompartmental arthroplasty is an efficient and approved treatment option of unicompartmental arthritis of the knee, being performed with increasing frequency worldwide. Compared to total knee replacement, there are several advantages such as faster recovery, lower blood loss, better functional outcome and lower infection rates. However, higher revision rates are a frequent argument against the use of unicompartmental arthroplasty. The following article gives an overview of failure mechanisms and strategies for revision arthroplasty. This article is based on a selective literature review including PubMed and relevant print media. Our own clinical experience is considered as well.     

Minimal-invasive Implantation unikondylärer Prothesen

Knee arthroplasty has become one of the most successful standard procedures in orthopaedic surgery. With a more frequent use in young and active patients bone-saving procedures have become more important. The goal is to save good bone stock for the revision procedure. Therefore, unicompartmental knee arthroplasty is a good example. Instrumentation and minimally invasive surgical techniques have been improved so very good long-term results and early functional results are achieved. The paper describes the surgical technique with true capsule incision and extramedullary alignment technique.In a prospective study, the early functional results with the ZUK implant were excellent. The implant may not be indicated for every knee situation and an exact differential indication and sound surgical technique are necessary. Its use, however, in cases with unicompartmental knee arthritis, contributes to excellent early rehabilitation and to maintaining autologous bone. Therefore, the minimally invasive unicompartmental knee arthroplasty is a sensible alternative to other options.     

Die In-vivo-Biomechanik von unikondylären Knieprothesen in minimal-invasiver Technik

Disturbed kinematics of the knee plays an important role in early failure of a unicondylar knee prosthesis (UNI). Recent studies on kinematics have shown that an intact anterior cruciate ligament (ACL) is important for a successful UNI. In this study, in vivo fluoroscopic analysis of knee kinematics was performed for 30 patients with a successful medial UNI implanted with the use of minimally invasive technique. The three-dimensional data of the CAD model were used for evaluating the sagittal translation as well as the axial rotation during deep knee bending and one gait cycle. The anteroposterior translation for flexion was, on average, -5.3 mm (-15.7-3.3; standard deviation 5.3). In most cases, the contact point was more posterior compared with the normal knee. During gait, the average anteroposterior translation was 0.8 mm, which is comparable to that of the normal knee. Axial rotation for deep knee bending was, on average, 8 degrees (-1.3-22.0; standard deviation 5.7), whereas 28 of the 30 knees showed normal axial rotation. During gait, an average axial rotation of 0.94 degrees was observed. The kinematic pattern of each of the subjects did not replicate the average pattern in most of the patients. An insufficient ACL may be suspected as the cause of the pathological kinematic pattern observed in some of these patients.     

Moderne unikondyläre Kniearthroplastik

Background

Unicondylar knee arthroplasty (UKA) is an established therapeutic option for advanced medial or lateral gonarthrosis.

Objectives

The cornerstones of a successful UKA, careful patient selection, preoperative planning and precise operation technique, are discussed in this overview article.

Importance

In contrast to total knee arthroplasty, UKA allows preservation of the contralateral and patellofemoral compartments as well as the cruciate ligaments and is often associated with rapid postoperative recovery, improved knee kinematics and knee function. However, UKA is technically very demanding. High revision rates have been reported in particular with widespread application, according to national joint replacement registries.

Conclusion

Successful UKA relies on meticulous patient selection, preoperative planning and surgical technique. It is justified to broaden classic UKA indications. In medial and lateral UKA three types of mechanical varus-valgus deformity can be encountered: type 1 (isolated intraarticular deformity), type 2 (pronounced deformity due to extraarticular varus deformity in medial UKA or valgus deformity in lateral UKA), type 3 (reduced deformity due to extraarticular valgus deformity in medial UKA or varus deformity in lateral UKA). We believe these deformities should be addressed accordingly with surgical technique.     

Minimal-invasive navigiert implantierte unikondyläre Knieendoprothese

METHODS: From January 2003 to July 2005 a total of 50 St Georg medial knee monosleds with metal-backed tibial components in stably seated form and Uniglide prostheses (Alphanorm/Corin) with mobile bearing onlays were implanted in minimally invasive operations. Postoperatively the alignment-especially of the tibial components-was investigated, to check whether we had achieved the dorsal slope we had been aiming at, i.e. 5-7 degrees , in the region of these knee replacements. RESULTS: Before surgery there were initial malalignments of up to 10 degrees varus and 3 degrees valgus. All leg axes were restored to between -3 degrees and +3 degrees . The desired dorsal slope of 5-7 degrees for the knee monosleds relative to the tibial component was realized, the average slope being 5.3 degrees . The a-p alignment of the tibial component and of the femoral component was correct. CONCLUSIONS: Use of the navigation system leads to more accurate and reproducible results in terms of tibial dorsal slope, which is extremely important when these monosleds are used. Overcorrection of the leg axis is generally avoided. The use of too-high medial onlays is also reliably avoided by the navigation system's monitoring of the level of the cut.     

Erfahrungen mit lateralen unikondylären Prothesen

Background

Unicompartmental osteoarthritis of the knee joint affects the medial compartment more often than the lateral compartment whereby the lateral is solely affected in only 5–10?% of cases. In this case unicompartmental knee arthroplasty has been shown to be an effective alternative to total knee arthroplasty. There are some basic anatomical and biomechanical differences between the medial and lateral compartment of the knee joint which directly influence modern surgery techniques and implant design. In general, kinematics and design are fundamentally different in mobile-bearing compared to fixed-bearing prostheses.

Objectives

This article presents a summary of outcome and survival rates after unicompartmental knee arthroplasty in the lateral compartment.

Methods

This article is based on a literature search in the PubMed database for clinical results after lateral unicompartmental knee arthroplasty.

Results

The results demonstrate that lateral unicompartmental knee arthroplasty with a mobile-bearing implant and a domed tibial plateau design gives an excellent clinical outcome while reducing the dislocation rate to an acceptable level in the short and mid-term. Published data on the clinical outcome of fixed-bearing lateral unicompartmental knee arthroplasty prostheses revealed heterogeneous results due to the inclusion of different implant designs and relatively small patient cohorts. Nevertheless, most of them demonstrated good clinical results with a longer follow-up than current studies concerning mobile-bearing prostheses.

Conclusion

Based on the published data it is not possible to demonstrate precise differences in clinical outcome and survival rates after mobile-bearing and fixed-bearing unicompartmental knee arthroplasty or to make clear recommendations on the use of each type of prosthesis.     

Die Implantation einer unikondylären Schlittenprothese

Objectives Correction of axial malalignment and restoration of a normal pain-free joint function through insertion of a unicompartmental runner. Indications Medial or lateral unicompartmental osteoarthritis. Osteonecrosis of the medial femoral condyle. Age over 60 years. Contraindications Osteoarthritis of more than one compartment. Ligamentous instability (instability due to cartilage loss is not a contraindication). Rheumatoid arthritis. Chronic synovitis. Systemic affections of joints (i. e., hemophilia). Neuropathic joint diseases. Obesity. Axial malalignment exceeding 20°. Flexion contracture exceeding 20°. Sugical Technique Medial approach. After visual confirmation that only one compartment is affected, resection of the tibial plateau while preserving cruciate and collateral ligaments. Preparation of the femoral condyle and restoration of axial alignment through insertion of the unicompartmental components. Avoid overcorrection. Results Between 1986 and 1990 a unicompartmental arthroplasty was done in 34 men and 115 women (62–86 years). 44 had died for unrelated reasons. 35 answered a questionnaire by phone, 45 could be examined clinically and radiologically. 23 patients had undergone a revision surgery for various reasons. The duration of follow-up varied between 8 and 12 years. The clinical assessment was based on the HSS score. Results were good to excellent in 80%, moderate in 7.5%, and poor in 12.5%. Patients with a poor result were scrutinized paying special attention to the surgical indication. Main reasons for poor results were rheumatoid arthritis, advanced osteoarthritis, loosening and subsidence of the tibial component. The survival rate after more than 10 years of 84 patients at risk, with the need of revision as endpoint, was 83.7%.     

Minimalinvasive Chirurgie primärer und sekundärer Lebertumoren

Background

Initially, mainly superficial liver lesions were resected laparoscopically but now even major resections are performed using a minimally invasive procedure. Careful selection of suitable patients is of key importance.

Aims and methods

This article describes the current state of the art in patient selection and choice of the appropriate laparoscopic technique based on a review of the recent literature. Perioperative and oncological outcome parameters of laparoscopic liver resection are presented.

Results

Laparoscopic liver resection offers significant benefits compared to open liver resection in terms of reduced intraoperative blood loss, reduced overall and liver-specific complications and length of hospital stay without compromising oncological outcomes.

Conclusion

Lesions in the peripheral anterolateral segments (segments 2, 3, 4b, 5 and 6) are particularly suitable for laparoscopic liver resection. Access to the posterosuperior segments 1, 4a, 7 and 8 is more challenging but safe and feasible in experienced centers.     

28. Primärer und sekundärer Hyperparathyreoidismus

Zusammenfassung Beim primären, autonomen Hyperparathyreoidismus führt die Parathormon (PTH)-Überproduktion zu Symptomen am Skelet und (infolge Hypercalciämie) an Nieren, intestinalen Organen, Zentralnervensystem u. a. Beim sekundären Hyperparathyreoidismus werden die Nebenschilddrüsen durch chronische Hypocalciämie (bei Niereninsuffizienz infolge Phosphatstau und Störung des Vitamin D-Stoffwechsels) stimuliert, Behandlungsbedürftigkeit ergibt sich bei Skeletschäden. Für die Diagnostik stehen Calcium-, PTH- u. a. blutchemische Bestimmungsmethoden zur Verfügung, sie werden ergänzt durch Röntgenologie und Knochenhistologie.Mit Unterstützung der Deutschen Forschungsgemeinschaft, SFB 87 Endokrinologie, Ulm     

Arthroskopische Arthrolyse bei primärer oder sekundärer Schultersteife

Objective of endoscopic arthrolysis of the shoulder is the restoration of joint mobility in the primarily or secondarily stiff shoulder. The indication is given in primary and idiopathic adhesive capsulitis and in secondary, posttraumatic contracture of the shoulder with intolerable complaints and a loss of function over 6 months despite conservative treatment. Relative contraindications are a frozen shoulder in its initial inflammatory stage and posttraumatic stiffness with incongruency of the joint. The operation is performed using an arthroscopic technique with three standard portals. After partial synovectomy, the capsule is incised mechanically or electrically, and optionally a capsule strip can be resected. Subsequently, paraarticular and subacromial debridement is performed. Postoperative physiotherapy is crucial and is complemented by a continuous passive motion splint. Arthroscopic arthrolysis can accelerate the spontaneous course of adhesive capsulitis and leads to good functional results in primary and secondary stiff shoulders.     

Mikrovaskulärer Gewebetransfer

Microvascular tissue transfer has rapidly developed to a routine method since is introduction approximately 30 years ago and is nowadays also the focal point of reconstructive procedures in oral and craniomaxillofacial surgery. Depending on the condition of the defect area, transplants with various tissue components can be acquired from many donor sites, which are distinguished by a constant anatomy and therefore allow standardized preparation techniques. Recently, the so-called perforator flaps have been discussed as an extension of this well-established technique and are characterized by minimal donor morbidity but often make an individual approach for flap raising necessary due to the wide variation in anatomy. Microvascular tissue transfer has become an indispensible component particularly in tumor surgery and success rates of 95% have been cited by large centers. It can therefore be considered an extremely safe reconstruction procedure in oral and craniomaxillofacial surgery.     

Primärer Hyperparathyreoidismus

Introduction

Normocalcemic hyperparathyrinemia, i.e. elevated parathyroid hormone (PTH) levels after parathyroidectomy in patients with primary hyperparathyroidism (pHPT) may occur in the course of postoperative recovery without the development of persistence or relapse.

Materials, methods and results

Intraoperative and long-term (7 year) postoperative PTH and calcium levels after curative parathyroidectomy are demonstrated on the basis of a case report of a 62-year-old female patient with severe pHPT and pronounced osseous and renal manifestations. The intraoperative PTH gradient displayed a decrease from 1072 pg/ml to 13 pg/ml (normal range 11–67 pg/ml) followed by an increase of up to 287pg/ml. The hyperparathyoid values decline to subnormal levels on administration of calcium and vitamin D and increase again after tapering these medications. The inverse calcium/PTH correlation in the course of the 7-year observation period suggests an intact feed-back mechanism. Preoperative PTH screening was performed in 316 consecutive normocalcemic thyroid patients to evaluate the rate of incidental hyperparathyroidism in patients with normal serum calcium levels. Of these patients 31 (9.8%) with normocalcemia (average 2.28 mmol/l, normal range 2.1–2.7 mmol/l) exhibited increased PTH levels averaging 84.2 pg/ml. A parathyroid adenoma was found intraoperatively as the cause for normocalcemic pHPT in only 1 of these 31 patients.

Discussion and conclusions

A review of the literature revealed that late postoperative elevated parathyroid hormone levels after successful pHPT surgery occur in 21.5%. Multiple causes are discussed, e.g. reactive hyperparathyroidism in cases of relative hypocalcemia, hungry bone syndrome, vitamin D deficiency, renal dysfunction and ethnic or lifestyle differences. In mild cases of postoperative hyperparathyrinemia observation of the patient may be sufficient. In cases of reactive hyperparathyroidism due to hypocalcemia, administration of calcium is indicated, in symptomatic patients, additional administration of vitamin D or calcitriol is necessary. Vitamin D deficiency per se needs adequate substitution. In cases of ongoing hyperparathyrinemia an interdisciplinary diagnostic and therapeutic approach is required.     

Primärer Megaureter

A primary megaureter is an anomaly with a prevesical or overall dilated ureter of more than 6 mm in diameter. It is important to distinguish between cases of primary non-refluxing and primary obstructive-refluxing megaureters, as the treatment of both is completely different. The basic diagnostic work-up includes ultrasonography and voiding cystourethrography. Diuretic renography is used to detect split renal function and the degree of upper urinary tract obstruction. In most cases of primary non-refluxing megaureter surgical treatment is unnecessary due to the high remission rate, whereas obstructive refluxing megaureters commonly only need to be corrected. Antibiotic prophylaxis may be indicated in infants with a primary obstructive megaureter during the first 6 months of life due to a higher risk of complications due to pyelonephritis especially in this age group.     

Umstellungsosteotomie vs. unikondyläre Prothese bei Gonarthrose

Background

Osteotomy around the knee and unicondylar knee replacement can both produce excellent results in unilateral knee osteoarthritis. The indications for these procedures differ significantly and are discussed in this article.

Methods

A weight-bearing long-leg radiograph, clinical stability tests and varus-valgus-stress radiographs are mandatory for a preoperative analysis. Osteotomy is a safe and reproducible procedure when a biplanar cutting technique is used and fixation is achieved with a plate fixator. Unicondylar knee replacement can be performed minimally invasive with a quadriceps-sparing arthrotomy.

Evaluation

High tibial osteotomy and unicondylar knee may produce good results in unilateral osteoarthritis of the knee. Our multicenter follow-up study with 533 patients revealed good functional outcome scores with a low complication rate. The subjective ratings were better than in comparable groups with unicondylar knee replacement and with total knee arthroplasty.

Conclusions

The main criterium for osteotomy versus unicondylar knee replacement is constitutional deformity of femur or tibia. In constitutional deformity, osteotomy has a very good prognosis. The results are not dependent on age, BMI, or grade of osteoarthritis. Activity and ligament stability of the knee are secondary criteria in favor of osteotomy. Medial osteoarthritis without constitutional deformity should be treated with unicondylar knee replacement.     

Behandlungsergebnisse nach primärer und sekundärer Radiusköpfchenresektion

Apart from comminuted fractures of the radial head the indication for resection of the radial head is discussed controversially. To evaluate our own results, the hospital notes of 113 patients treated between 1.1.1984-31.12.1994 in our clinic by posttraumatic primary or secondary radial head resection were examined retrospectively. 79 patients were controlled by clinical and radiological examination with an average follow-up of 37.8 months. We examined at 46 patients the influence of additional lesions of the elbow joint on the functional outcome. In 33 patients follow up was done with special regard to the time of resection. Poor results due to the score from Radian and Riseborough especially followed secondary radial head resection (> 14 days after trauma) and in case of additional elbow lesions. We could not observe problems of the wrist joint after radial head resection as described by other authors. According to our own experience primary resection is recommended in case of doubtful reconstruction of the radial head. In these fracture types radial head resection should not be seen as an alternative treatment because of the worse results following secondary resection.     

Qualitätssicherung interdisziplinärer Polytraumaversorgung

BACKGROUND: The purpose of this study was to evaluate the quality of interdisciplinary multiple trauma management using routinely taken data. METHODS: A retrospective analysis of all multiple traumatized patients [Injury Severity Score (ISS)>15] in a university hospital (n=172; time period 01.01.1997-31.12.1999) was carried out concerning epidemiological and clinical variables and hospital outcome (p<0.05). RESULTS: The overall mortality was 22% [n=38; expected Trauma Injury Severity Score (TRISS) mortality 29%]. Significant parameters for worse outcome in univariate analysis were age>74 years, hypotension, decreasing hemoglobin level and prothrombin time, decreased Glasgow Coma Scale and the number of erythrocyte or plasma concentrates received in the initial period of treatment. The comparison of our results with the data of the German Association for Trauma Surgery registry demonstrated comparable results with respect to management sequence and outcome. CONCLUSIONS: In the quality management of multiple trauma patients retrospective analysis of routinely registered parameters can be a reliable and practical alternative to time-consuming prospective studies when based on prognostic relevant data. Such a procedure allows a preliminary critical comparison with other centers.