Die Entwicklung des Oberflächenersatzes der Hüfte

Total hip replacement in its current form has proved to be very effective in late middle-aged and elderly patients. However, in the younger patient population the survival rate is still not acceptable. Since the very beginning of hip resurfacing, the procedure has been advocated as an attractive concept to preserve proximal femoral bone stock. Furthermore, it is supposed to optimize stress transfer to the proximal femur and because of the large head size improves joint stability and range of motion. The failure of previous resurfacings has been described to be due to inappropriate materials, poor design, and poor instrumentation and not as an inherent problem of the procedure itself.Progress in materials and material design (metal-on-metal) as well in experience in surgical technique seem to have overcome formerly experienced difficulties. This means a lower rate of femoral neck fractures and aseptic loosenings, at least in the short-term and midterm follow-up of patients with good function.High manufacturing standards are required to consistently produce low-wear metal-on-metal bearings and it is still unclear whether high metal ion levels, which occur in all patients with metal-on-metal hip replacements, have any biologic effect. At least so far there is no evidence of any negative clinical effect in this regard. Only long-term results in a higher number of patients and a more widespread use of this procedure will tell whether early success is durable or it is just a bone-preserving, intermittent step before conventional total hip replacement.     

Die Luxation als seltene Komplikation des Oberflächenersatzes am Hüftgelenk

Resurfacing of the hip joint experienced a revival in the 1990s. Today metal-on-metal bearing is a therapy option especially for younger, active patients. In comparison to stemmed total hip replacements resurfacing offers advantages, in particular in view of the femoral bone loss. The short-term results are very good. In the current literature revision rates of less than 1% are reported.In comparison to conventional total hip replacement, dislocation is a rare complication. With conventional total hip replacement the dislocation rate is 2-5%. In the international literature the dislocation rate with resurfacing is 0.21%.     

Oberflächenersatz des Humeruskopfs

Cup resurfacing of the humeral head is one of the possible prosthetic solutions for severe destruction of the glenohumeral joint. Because neurological complications are not uncommon after total shoulder arthroplasty using surface replacement, these cups are indicated when hemiarthroplasty is possible. The advantages of humeral head resurfacing are bone preservation and the technically easy exchange if revision is necessary; therefore, young patients are candidates for this type of endoprosthesis. At present humeral head resurfacing is indicated for osteoarthritic destruction of Walch types A1 and C, for rheumatic destruction with deficient cuff in younger patients, cuff arthropathy in younger patients with Seebauer types 1A and 1B, humeral head necrosis with normal glenoid and necrotic bone in less than one third of the humeral head and dislocation arthropathy in younger patients.     

Oberflächenvermessung des Rückens

X-ray study to verify clinical findings in patients with scoliosis and other deformities of the spine is associated with considerable radiation exposure as well as a variety of other problems, particularly as regards assessing disease progression. Hence, in the course of the past few years a number of alternative, supplementary spinal diagnostic procedures have been developed which are based on analysis of the surface of the back: Moiré topography, photogrammetry/raster stereometry, opTRImetric system, ISIS system, video raster stereometry (formetrics), ultrasound-guided spine analysis (Zebris) and ultrasound topometry. To assess the effectiveness of screening, diagnosis, and progression of scoliosis the formetric system of video raster stereometry and the Zebris system for ultrasound-guided spine analysis were tested. It was shown that the results of screening tests, diagnostic study, and progression evaluation of scoliosis and sagittal deformities were exact enough using these systems. Furthermore, the ultrasound-guided Zebris system offers the option of dynamic analysis of spinal movement. Limitations in measurement precision were found in obese patients, asymmetric muscle surfaces, and in patients who had undergone surgery, although in the latter group progression could be reliably monitored if the radiological angle was known. We can assume that surface analysis procedures will gain in importance clinically and in practice.     

Zementfreier Oberflächenersatz bei Dislokationsarthropathie des Schultergelenks

Background

Only a few reports in the literature describe that total shoulder replacement provides better functional results in dislocation arthropathy than hemiarthroplasty. Nevertheless, the risk of aseptic loosening in young and active patients is high after long-term follow-up. We evaluated the results of cementless humeral head resurfacing in this group.

Methods

We evaluated 29 patients with dislocation arthropathy who had been followed up for a mean of 39 months. The mean age at the time of operation was 43.7±14.7 years. Preoperatively, cuff deficiency was seen in 11 cases.

Results

The mean adjusted Constant score improved from 16.8±15.2% to 78.1±21.9%. Negative prognostic factors turned out to be female sex, age, cuff tears especially of the subscapularis tendon, and previous bone block procedures. Revision was performed in five patients, and two developed painful glenoid erosion which required conversion to total shoulder arthroplasty.

Conclusion

Cementless humeral head replacement is a viable option in the treatment of dislocation arthropathy. Revision can be performed easily since the bone stock has been preserved. On the basis of our data, humeral head replacement in patients <40 years with dislocation arthropathy offers promising short- to midterm results with an acceptable complication rate.     

Periprothetische intertrochantäre Femurfraktur nach Oberflächenersatz des Hüftgelenks

Improvements in implant design, material combination and operating instruments have led to an increased number of resurfacing arthroplasties of the hip joint especially in younger patients. Therefore, there is generally a higher risk of periprosthetic fractures even with this type of prosthesis. These fractures are divided into mainly iatrogenic fractures of the head/neck part of the femur and trochanteric fractures of the femur caused by trauma. Especially in the second group preservation of the prosthesis is much desired since the patient cohort is often very young and active. We report on a 31-year-old male patient who suffered an intertrochanteric fracture (classification AO 31 A2.1) after resurfacing arthroplasty of the hip joint (McMinn BHR prosthesis). The patient was treated with 3 AO lag screws by the percutaneous technique following closed reduction. During follow-up 22 months after the operation the reduction was preserved and the fracture fully consolidated with a good range of motion of the hip joint. The Harris hip score gave a result of 97 points.     

Oberflächliches Harnblasenkarzinom

Die Urologie - Das Blasenkarzinom ist der fünfhäufigste Tumor des Mannes mit steigender Inzidenz in den letzten Jahrzehnten. 80 % aller Blasentumoren wachsen oberflächlich, die...     

Einsatz der Navigation beim Oberflächenersatz des Hüftgelenks

Hip resurfacing received a renewed boost through the introduction of the BHR (Birmingham hip resurfacing) system. One can assume that with the BHR system major disadvantages of previous resurfacing systems have been overcome. Among the most remarkable improvements are the metal on metal bearing as well as the equipment for the exact positioning of the femoral component through guided drilling, reaming and an insertion of the implant.The purpose of the presented study was to find out whether by using a fluoroscopic navigation system the preparation of the femoral head and the positioning of the femoral component can be made easier and more precise. We developed a standardised procedure, which comprised the preoperative planning as well as the intraoperative application of the navigation system up to the drilling of the central rod, through which all of the reaming tools are guided and, finally, the component is also fitted.In 31 cases, the procedure showed excellent performance and reliability.A very exact, preferably steep (valgus) implantation of the femoral component was achieved without erosion of the femoral neck cortex ("femoral notching").The difference between the intraoperative angles of the component's position indicated by the navigation system and the postoperative results on x-rays averaged 2.6 degrees (0.89 degrees SD), which is close to the actual limits of accuracy for fluoroscopic systems.The realisation of the project was achieved with standard hardware (navigated drill guide) and navigation system software. The virtual positioning of the implant in the optimal position impressed as an important comfort gain. The additional operating time was 10-15 min in the last ten cases.     

Versuche des Ersatzes und der Ausnutzung von Oberflächen-Sensibilität bei Armprothesen

Ohne ZusammenfassungMit 10 Textabbildungen (16 Einzelbilder)Herrn Professor Dr. med. S. Weil zum 80. Geburtstag gewidmet.     

Tätigkeit des Herzens bei verschieden starkem Druck auf seine Oberfläche

Ohne Zusammenfassung Zum Teil nach Vortr?gen 1.) auf der 53. Tagung der Dtsch. Ges. f. Chir. 1929, Berlin ; 2.) auf der 41. Tagung der Dtsch. Ges. f. inn. Med. 1929, Wiesbaden ; 3.) im Verein f. inn. Med. u. Kinderheilk., 17. 6. 29, Berlin. Die Arbeit ist mit Unterstützung der Notgemeinschaft der deutschen Wissenschaft ausgeführt worden.     

Der Oberflächenersatz des Humeruskopfes bei avaskulären Nekrosen und posttraumatischen Zuständen

Zusammenfassung Einleitung   Der Oberfl?chenersatz an der Schulter hat sich in den letzten Jahren zunehmend etabliert und scheint in manchen Situationen vergleichbar oder sogar von Vorteil gegenüber der konventionellen endoprothetischen Versorgung an der Schulter zu haben. Studienziel   Das Ziel der vorliegenden Untersuchung war die klinische und radiologische Evaluation von zementfreien Oberfl?chenprothesen (Copeland™) im Bereich der Schulter bei oss?ren Defektzust?nden. Patienten und Methoden   In die Studie wurden 18 konsekutive Patienten mit Humeruskopfdefektzust?nden (8 Patienten mit posttraumatischen Kopfnekrosen, 8 Patienten mit avaskul?rer Humeruskopfnekrose, 2 Patienten mit chronischer dorsaler Luxation). Es handelte sich um 8 Frauen und 10 M?nner. Das mittlere Alter betrug 55,3 Jahre (27–71 Jahre). Die Patienten wurden prospektiv klinisch und radiologisch untersucht. Der mittlere Nachuntersuchungszeitraum betrug 24,8 Monate (10–78 Monate). Die klinische Dokumentation erfolgt anhand Constant-Scores. Ergebnisse   Der mittlere Constant-Score verbesserte sich von 14,83 auf 64,34 Punkte. Der mittlere Schmerz-Score verbesserte sich von 0,3 Punkten (0–5 Punkte) pr?operativ auf einen Wert von 9,8 Punkten (5–15 Punkte). Das mittlere Bewegungsausma? verbesserte sich im Constant-Score von 8,21 Punkten (2–10 Punkte) pr?operativ auf einen postoperativen Wert von 23,21 Punkten (2–32 Punkte). Das humerale Offset nahm von 22,3 mm pr?operativ auf 28,8 mm postoperativ zu. Fazit   Der Oberfl?chenersatz an der Schulter bei Patienten mit oss?ren Defektzust?nden im kurzen und mittelfristigen Verlauf erbringt gute und akzeptable klinische Ergebnisse.      

Intramedulläre Nagelosteosynthese der Ulna in der Revisionschirurgie

The exact and adequate management of diaphyesal fractures of the forearm is necessary to ensure forearm motion. Unsatisfactory treatment can lead to loss of function and disability of forearm and hand movement, resulting in severe patient morbidity. Since the rotational and angulatory stresses at the fracture site are the superior factors which influence the outcome of the forearm fracture healing after surgical treatment, the implants must fulfill some general prerequisites including high biomechanical stability, less invasive surgical approach and adequate biological features. However, less clinical studies are known for cases of complicated ulnar fractures when additional revision surgery is necessary to restore form and function. Thus, the choice of implant in such difficult situations requires a profound knowledge and experience. In a series of seven clinical cases we report about the successful use of the ForeSight-nail in revision surgery of complicated ulnar fractures. The series include cases with refractures after plate removal, in-situ plate brokerage and a critical size bone non-union which were treated with interlocking intramedullary osteosynthesis technique.     

Der zementfreie Oberflächenersatz des Humeruskopfes bei Patienten unter 55 Jahren

Background

Cementless humeral surface replacement arthroplasty is a viable treatment option for degenerative diseases of the shoulder joint. The aim of this prospective study was to analyse the results of this treatment option in patients younger than 55 years of age with different pathologies of the shoulder.

Patients and methods

Twenty-three patients (26 implants) treated with cementless humeral surface replacement arthroplasty were included in this study. Mean follow-up was 2.5 years (1–6 years). Ten patients had posttraumatic osteoarthritis, seven had primary osteoarthritis, and six had osteonecrosis. Patients were evaluated using the Constant score, shoulder motion, and subjective satisfaction.

Results

The mean Constant score increased significantly from 33 points preoperatively (8–69 points) to 61 points postoperatively (25–83 points; p<0.0001), adjusted to age and gender from 38% (8–86%) to 70% (28–114%; p<0.0001). Significant improvement for the whole cohort was found regarding patients’ pain, activity, mobility, shoulder flexion and abduction, and internal and external rotation (p<0.001). In one case, reoperation was necessary due to a superficial wound infection, and in another case, implant revision to a total shoulder replacement was performed because of glenoid erosion.

Conclusion

Cementless humeral surface replacement arthroplasty is a viable bone-preserving treatment option for young and active patients. Later conversion to total shoulder replacement is possible. Good clinical results, a low complication rate, and high patient satisfaction were found in the short and mid term. Long-term investigations are necessary to confirm these observations.     

Welchen Einfluss hat die Größe und Platzierung des Patellarückflächenersatzes bei Knieendoprothesen?

The aim of this study was to document the changes in retropatellar pressure, contact area and forces due to different sizes and placement of the patella resurfacing in knee arthroplasty. Six cadaver specimens (after Thiel fixation) were examined after the implantation of the total knee arthroplasty Genesis I. The patella sizes "small" and "medium" were placed as the "onlay" version, centered as well as off-centered by 0.4 cm in all four directions. Pressure and area measurements were done with Fuji pressure measuring film, which was placed between the patellar fascia of the femur and the patella in a defined position. The pressure was measured by applying a predetermined force for 5 s. The examinations were done with 60 degrees knee flexion and a force of 280 N. In our results there were no significant differences between, patella sizes. No significant differences for the medial, distal and proximal placement were found for the small patella. The lateral placement led to a significant decrease in the contact area (P = 0.0277), maximum pressure (P = 0.0422) and force (P = 0.0277). The average pressure did not change significantly (P = 0.1159). For the medium size patella there were no significant differences for medial or distal placement. The comparison of lateral and central placement revealed a significant decrease in the contact area (P = 0.0446). Comparing distal and proximal positioning, a significant increase in contact area and significant decrease in force were found (P = 0.0277 and P = 0.0277 respectively). In conclusion, the choice of small or medium patella resurfacing does not seem to have a significant influence. In comparison to the results without patella implants, the implantation of the small patella caused a significant decrease in the retropatellar contact area (P = 0.03) and force (P = 0.03). Average and maximum pressure did not change significantly (P = 0.6 and P = 0.35) even though pressure increased slightly. For the medium size, maximum pressure (P = 0.03) increased significantly and force decreased significantly (P = 0.0277) whereas contact area and average pressure increased slightly. The results of the different placements of the patella implant do not support the recommendation for a medial shift. However, at least the lateralized implantation led to a reduction of contact area and force as well as to a slight increase of pressure which is considered as unfavorable.     

Die femorale Zementiertechnik für den Oberflächenersatz des Hüftgelenks

In recent retrieval studies, overpenetration of cement, incomplete seating of the prosthesis with a resulting polar cement mass, or both have been associated with failure of current-generation femoral resurfacing arthroplasties. Cementing technique was found to strongly influence cement pressure, interface temperature, and cement penetration in the few cementing studies published on hip resurfacing arthroplasty. Component-filling cementing techniques resulted in a risk of incomplete seating, variable degrees of overpenetration of the interior area, and a lack of cement at the outer lower edges of the bone under the resurfacing components. This caused exposure to high temperatures, which can cause bone necrosis. The manual technique with high-viscosity cement showed advantages in our experimental work. It was possible to achieve high cement contents in the outer fixation area without the negative effects of interior area penetration.     

Azetabuläre Defektrekonstruktion in der Revisionschirurgie der Hüfte

The treatment of periprosthetic bone defects of the acetabulum is a therapeutic challenge in hip revision surgery. The aims are the biological reconstruction of osseous acetabular defects and the restoration of a load-bearing acetabular bone stock as well as restoring the physiological joint biomechanics and achieving primary and load-stable fixation of the revision graft in the vital pelvic bone. The biological reconstruction of the acetabular bone stock should include what is referred to as “down-grading” of the acetabular defect situation in case a repeat revision procedure becomes necessary. Nowadays, a large variety of grafts and reconstruction procedures are available for the reconstruction of acetabular defects. The choice of suitable materials (osseous or metallic) for the restoration of a load-bearing acetabular bone stock is currently the subject of controversial discussion. This article reviews the various options for the reconstruction of acetabular bone defects taking into consideration the current findings in the scientific literature.