Der Anbindungsschlauch zur Weichteilrekonstruktion nach Megaprothesenimplantation

Objective

To restore function and an active range of motion, and stabilize the joint after joint resection.

Indications

Restoration of a joint capsule following reconstruction of a defect using a proximal humerus and femur prosthesis. Reattachment of tendons and muscles.

Contraindications

Acute or chronic infection. Status after cured infection.

Surgical technique

The attachment tube (Implantcast, Buxtehude, Germany) is attached to the joint capsule (proximal humerus and femur replacement) or directly to the prosthesis (for proximal tibial replacements) using nonresorbable Ethibond? sutures (Johnson &; Johnson Medical, Norderstedt, Germany). Bone anchors are used, if the joint capsule has been completely resected. The body of the prosthesis, which has previously been attached to the shaft, is then pulled distally through the tube, and a (bipolar) head or humerus cap is placed on top of it. In the proximal humerus and femur replacement, proximal slitting of the tube may be helpful to reposition the prosthesis under vision. Following repositioning, fixation of the tube is completed ventrally and the slits previously made in the tube are sutured. Fixation of the tube to the prosthesis is carried out either with Ethibond? sutures placed around the tube, or??for a proximal humerus and tibia replacement??it is possible to attach suture material to the prosthesis through eyelets.

Postoperative management

Further treatment basically depends on the location of the mega-endoprosthesis used.

Results

Macroscopically and microscopically, fibroblasts migrate into the tube??s mesh, so that attachment of the soft tissue takes place. As of yet, no cases of luxation have occurred when the tube is used in combination with a bipolar head, and with fixed-implant cups the risk of luxation can be reduced using tripolar cup systems. In patients with a proximal tibial replacement, active straightening of the knee joint can be restored in most cases, although some limitation on active extension is still possible depending on the extent of the tumor resection.     

Evaluation of a reconstruction reverse shoulder for tumour surgery and tribological comparision with an anatomical shoulder arthroplasty

Purpose

The functional results after reconstruction of the proximal humerus in tumour surgery are poor. Therefore, a reversed proximal humerus replacement was developed in our institution (MUTARS humerus inverse). A low degree of wear on the polyethylene is required because of the patients’ youth and demands on shoulder function. A special type of polyethylene with shock-absorbing properties has been developed to minimise polyethylene wear in the MUTARS inverse proximal humerus replacement. We compared the tribological properties of an anatomical shoulder prosthesis (CAPICA) with the new reversed proximal humerus replacement (MUTARS humerus inverse).

Methods

Both prostheses were tested up to 5 × 10⁶ cycles. Every millionth cycle the surface was inspected and a gravimetric measurement was performed. A measurement of surface roughness was done before testing and after 5 × 10⁶ cycles.

Results

In both prostheses after 5 × 10⁶ cycles there were no major defects, such as delamination, observed. In the reversed proximal humerus replacement abrasion of 28 mg/10⁶ cycles was detected. The mean abrasion of the anatomical prosthesis was 9.28 mg/ 10⁶ cycles.

Conclusion

The glenoid component of the first reversed humerus replacement (MUTARS humerus inverse) has wear properties comparable to those of normal reversed shoulder prostheses. This is important, as this type of prosthesis is used in young patients after resection of bone tumours, with a good functional outcome. It can, therefore, be expected that the revision rate due to wear will be as high as in patients with normal reversed shoulder prostheses.     

Giant cell tumor of bone: treatment and outcome of 214 cases

BACKGROUND: Two hundred and fourteen patients with benign giant cell tumor of bone (GCTB), treated from 1980 to 2007 at the Department of Orthopedics of the University of Muenster (Germany), were analyzed in a retrospective study. PATIENTS AND METHODS: The mean age was 33.3 years with a female-to-male ratio of 1.2 : 1. The mean follow up was 59.8 months. The recurrence rate of patients who received first treatment at our institution was 16.6%. The most common primary treatment was curettage (188 patients) usually followed by adjuvant local therapy. The effects of bone cement (PMMA), burring and hydrogen peroxide (H(2)O(2)) were statistically analyzed and the influence of a subchondral bone graft on the recurrence rate was evaluated. RESULTS: PMMA alone (n = 52) reduces the likelihood of recurrence by the factor 8.2, additional high-speed burring (n = 39) by the factor 3.9 (compared to PMMA only). H(2)O(2) (n = 42) seems to have an additional effect comparable to that of phenol although it did not reach statistical significance. CONCLUSION: The combination of all adjuncts (PMMA, burring, H(2)O(2) - n = 42) reduces the likelihood of recurrence by the factor 28.2 compared to curettage only and therefore should be recommended as a standard treatment. If the tumor reaches close to the articulating surface a subchondral bone graft (n = 42) can be performed without risking a higher recurrence rate. We add seven cases of pulmonary metastases and two cases of multicentricity to the literature. Bisphosphonates and interferon alpha may have a beneficial effect.     

Reconstruction after wide resection of the entire distal fibula in malignant bone tumours

In this study we present a series of patients (n = 11) with resection of the entire distal fibula in the case of sarcoma or metastasis. Moreover, we describe a new method to restore ankle stability with a tibiotalocalcaneal arthrodesis using a retrograde hindfoot nail (n = 4) in contrast to tibiotalar arthrodesis with screws (n = 5). The screw fixation failed in two patients due to osteopoenic bone. The crucial benefits of an arthrodesis with a retrograde nail are a stable arthrodesis, intramedullary stabilisation of the tibia and avoidance of extrinsic material in the wound area. An arthrodesis with a retrograde nail is a good alternative for reconstruction after a wide distal fibula resection. The additional arthrodesis of the subtalar joint was not associated with worse functional results in the MSTS and TESS scores.     

Operative Techniken in der Tumororthopädie

Background

Limb salvage procedures with modular megaendoprostheses are now well established. In the majority of patients suffering from a bone tumor, an extremity-preserving operation can be carried out.

Materials and methods

Selection of the suitable reconstruction procedure depends on the localization and extent of the defect and also the age and constitution of the patient. Basically biological and endoprosthetic procedures are available. Operative reconstruction is carried out using modular tumor endoprostheses but a wide margin resection of the tumor is a prerequisite. Radical extracompartmental resection is currently no longer necessary. Ablative procedures, such as amputation or rotation plasty are now only indicated in cases of tumor infiltration of nerves and vessels and large soft tissue components with almost impossible coverage of the implanted prosthesis.

Results

Almost every joint and even an entire bone (e.g. total femur or total humerus replacement) can be replaced with promising functional results by modular tumor endoprostheses. The major complications after endoprosthetic reconstruction are local recurrence (1–9?%), periprosthetic infections (5–36?%) and aseptic stem loosening (5–27?%). Abrasions of the polyethylene components in distal femur or proximal tibia replacements are unavoidable in young and physically active patients.     

The primary stability of the hip transposition type IIb: A biomechanical in vitro study

Background

The hip transposition is firmly established in pelvic sarcoma surgery. However, the primary stability of the hip transposition has not been tested yet so that the mobilisation, respectively the immobilisation of the patient so far solely relied on the experience of the surgeon. The aim of this study was to test the primary stability reliably with the help of a model and to reveal possible differences in stability between currently used anchor systems (TwinFix^® 6.5 and MITEK^® SuperAnchor^®).

Methods

A biomechanical model of porcine sacra was developed to document the maximum load capacity (load to failure test) and the performance under cyclic load (100 N, 200 N, 350 N, 700 N, 1400 N, each with 1000 cycles), 28 sacra were tested in total. Macroscopic damages, displacement, yield load, stiffness and F_max were recorded as well.

Findings

The load to failure test results showed a 3,9 times higher maximum load capacity for the TwinFix^® 6.5 anchor (1307 N) compared to the MITEK^® SuperAnchor^® (334 N). The cyclical test revealed that nearly all MITEK^® SuperAnchors^® failed at a load of 350 N. In contrast, the TwinFix^® 6.5 anchors resisted 4000 cycles up to a load of 1400 N.

Interpretation

The TwinFix^® 6.5 anchor proved to be clearly superior to the MITEK^® SuperAnchor^®, resulting in the adjustment of the reconstruction technique. Therefore, the immobilisation period of a patient after a hip transposition type IIb could be shortened according to the results of the primary stability test.     

Cigarette smoking and drug use in schoolchildren: III--evaluation of a smoking prevention education programme

A one year randomized controlled trial was used to evaluate the effectiveness of a smoking prevention programme designed by health educationalists for 10-12 year old primary schoolchildren. The study was carried out in the Hunter Region of New South Wales, Australia, using a sample of over 6000 children which would be large enough to detect, with high probability, differences of about 5% in smoking prevalence between the treatment and control groups. We report the results from the children surveyed in 1979 and 1980, before and after the programme was implemented. It was found that there were no significant differences in smoking behaviour between treatment and control groups. The changes that the programme did bring about were very small compared with the overall increases in smoking prevalence which occurred during the study period. The programme's effectiveness varied with both the age and sex of the children. It was most successful among older girls, aged 11-12 years, for whom smoking prevalence rates increased from 10.7% in 1979 to 22.6% in 1980 in the treatment group compared with 6.2% to 26.8% in the control group. It was least successful for younger boys, aged 10-11 years, for whom smoking increased from 9.4% to 14.5% in the treatment group compared with 10.3% to 11.8% in the control group. Attitudes changed in parallel with changes in smoking behaviour. Changes in knowledge differed only slightly between treatment and control groups. Inadequate implementation of the programme by some teachers may have been associated with adverse effects on the children's behaviour, attitudes and knowledge.     

Rotationplasty type BI versus type BIIIa in children under the age of ten years. Should the knee be preserved?

Type BI rotationplasty is currently indicated for children with tumours of the proximal femur whereas type BIIIa rotationplasty is reserved for those in which the entire femur has to be removed. Our aim was to compare these two types of rotationplasty and determine whether the knee should be preserved in children with tumours of the proximal femur. We compared the post-operative complications, oncological outcome, range of movement, Enneking score and radiographs of six children, who had undergone type BI rotationplasty with those of 12 who had undergone type BIIIa rotationplasty. Patients with type BI rotationplasty had a mean Enneking score of 21.6 compared with 24.4 in those with type BIIIa rotationplasty, and worse mean results in all of the parameters investigated. We conclude that type BI rotationplasty has a worse functional outcome and more complications than type BIIIa rotationplasty in children under the age of ten years.