Pneumatic compression with foot pumps facilitates early postoperative mobilisation in total knee arthroplasty.

Deep-vein thrombosis (DVT) and pulmonary embolism (PE) represent life-threatening postoperative complications frequently responsible for in-hospital mortality following total knee arthroplasty (TKA). Mechanical prophylaxis in the form of a foot pump offers an alternative to pharmacological and physical therapy. The aim of this prospective and randomised study was to examine the clinical efficacy of the A-V Impulse (AVI) system in reduction of soft-tissue swelling of the lower limb following a TKA. A total of 80 patients undergoing cemented TKA between September 2005 and December 2006 were randomised into two groups of 40 patients (n¹ = 40, n² = 40) during the 16-month study period. All patients received a subcutaneous dose of low molecular weight heparin (LMWH) (Enoxaparin/Clexane® 40 mg) once daily beginning 24 hours prior to the operation. The mean age for the groups n¹ and n² were 68.93 and 68.15 years, respectively. The reduction of soft-tissue swelling in the n¹ group was significantly higher (p < 0.05) compared with n². Evaluation of body mass index (BMI) with regard to the average reduction of soft-tissue swelling showed no significant influence (p < 0.05). The better function of the operated knee in group AVI was a significant predictor for improved agility and mobility (p < 0.01). No complications were reported for the application of the AVI. No ultrasonographic evidence of DVT or PE was found in any of the 80 patients during the investigative time period of eight days. After three months, there was no evidence of a symptomatic DVT.

In vivo measurement of polyethylene wear in cementless total hip arthroplasty.

PURPOSE OF THE STUDY: Recent years have seen an increase in cementless total hip endoprosthesis (THP) implantations. Easy radiological measurement of wear in cups coated with X-ray dense material, such as metal or ceramics, is not applicable. An alternative technique has thus been developed to radiographically measure wear on cementless spherical implants. MATERIAL AND METHODS: The authors present a method in which the center of the head of the prosthesis relative to the center of the cup was defined by graphical extrapolation. Changes between the two centers on subsequent images allowed the estimation of wear. Data from 148 randomly selected patients with cemented THP were compared with that from 50 with cementless THP (head diameter always 32 mm). RESULTS Within the cemented group metal heads showed significant more wear than ceramic heads (1.244 mm vs. 0.504 mm). However, calculating the wear rate per year showed no significant difference. No significant differences were observed comparing cemented and cementless group. A comparison of the own results with those of the literature revealed analogous values. DISCUSSION: Data of the cementless group were comparable with those obtained from conventional wear measurements on cemented hip cups thus validating the technique. CONCLUSION: The method offers the potential to define wear of metal cups with a polyethylene inlay or with X-ray dense components such as ceramic or metal inlays.

Gelatin-based haemostyptic Spongostan as a possible three-dimensional scaffold for a chondrocyte matrix?: an experimental study with bovine chondrocytes.

The gelatin-based haemostyptic compound Spongostan was tested as a three-dimensional (3D) chondrocyte matrix in an in vitro model for autologous chondrocyte transplantation using cells harvested from bovine knees. In a control experiment of monolayer cultures, the proliferation or de-differentiation of bovine chondrocytes was either not or only marginally influenced by the presence of Spongostan (0.3 mg/ml). In monolayers and 3-D Minusheet culture chambers, the cartilage-specific differentiation markers aggrecan and type-II collagen were ubiquitously present in a cell-associated fashion and in the pericellular matrix. The Minusheet cultures usually showed a markedly higher mRNA expression than monolayer cultures irrespective of whether Spongostan had been present or not during culture. Although the de-differentiation marker type-I collagen was also present, the ratio of type-I to type-II collagen or aggrecan to type-I collagen remained higher in Minusheet 3-D cultures than in monolayer cultures irrespective of whether Spongostan had been included in or excluded from the monolayer cultures. The concentration of GAG in Minusheet cultures reached its maximum after 14 days with a mean of 0.83 +/- 0.8 microg/10(6) cells; mean +/-, SEM, but remained considerably lower than in monolayer cultures with/without Spongostan. Our results suggest that Spongostan is in principle suitable as a 3-D chondrocyte matrix, as demonstrated in Minusheet chambers, in particular for a culture period of 14 days. Clinically, differentiating effects on chondrocytes, simple handling and optimal formability may render Spongostan an attractive 3-D scaffold for autologous chondrocyte transplantation.

[Development of a catalogue of undergraduate learning objectives for orthopaedics and traumatology]. / Entwicklung des Lernzielkatalogs "Muskuloskelettale Erkrankungen, Verletzungen und traumatische Notfälle" für Orthopädie-Unfallchirurgie im Medizinstudium.

BACKGROUND: The development towards a combined speciality of orthopaedic and trauma surgery requires not only consolidation and revision of the postgraduate education training programme but also the development of a catalogue of learning objectives as a uniform basis for undergraduate medical training in the new speciality at German medical schools and teaching hospitals. MATERIALS AND METHODS: Based on the Frankfurt catalogue of learning objectives for trauma surgery and the Ulm catalogue of learning objectives for orthopaedics, a task force of experts developed a combined catalogue of learning objectives for the new speciality. Experts from both specialities classified the learning objectives into two levels of knowledge and four grades of skills competence, in addition to objectives for attitudes and social competence. RESULTS: The section on general operative specialities contains 120 items classified into 39 learning objectives for knowledge and 83 for skills. Two learning objectives comprise both knowledge and skills. The section on orthopaedic and trauma surgery comprises 141 learning objectives, including six items for skills and 138 for knowledge, as well as three learning objectives for both knowledge and skills. In addition, 22 learning objectives deal with aspects of attitude and social competence. CONCLUSION: Although this alliance of orthopaedics and trauma surgery is recent, the commission has developed not only a collection of topics but a joint catalogue of learning objectives for undergraduate training that can be used nationwide. This catalogue paves the way for modern education that looks to the future. The integrated recommendations for content prioritisation, links to other subjects and specialities, and the integration of didactic methods facilitate local implementation of the learning objectives without loss of academic freedom.

[Development of a catalogue of undergraduate learning objectives for orthopaedics and traumatology]. / Entwicklung des Lernzielkatalogs "Muskuloskeletale Erkrankungen, Verletzungen und traumatische Notfälle" für Orthopädie--Unfallchirurgie im Medizinstudium.

BACKGROUND: The developments towards a combined specialty of orthopaedic and trauma surgery requires not only the consolidation and revision of the postgraduate education training programme but also the development of a catalogue of learning objectives as a uniform basis for undergraduate medical training in the new specialty at German medical schools and teaching hospitals. MATERIALS AND METHODS: Based on the Frankfurt Catalogue of Learning Objectives for Trauma Surgery and the Ulm Catalogue of Learning Objectives for Orthopaedics, a task force of experts has developed a combined catalogue of learning objectives for the new specialty. The experts of both specialties classified the learning objectives into 2 levels for knowledge, into 4 grades of competence for skills, as well as attitudes and social competence. RESULTS: The general part of the operative specialties contains 120 items classified into 39 learning objectives for knowledge and 83 for skills. Two learning objectives comprise both knowledge and skill. The part orthopaedic and trauma surgery comprises 141 learning objectives, six items for skills, 138 for knowledge, as well as three learning objectives for both knowledge and skills. In addition, 22 learning objectives deal with aspects of attitudes and social competence. CONCLUSION: In spite of the only recent alliance of orthopaedics and trauma surgery, the commission has developed not only a collection of topics, but also a usable joint catalogue of learning objectives for undergraduate training with a nationwide recommendation character. The catalogue paves the way for a forward-looking, modern education. The integrated recommendations for the prioritisation, the linkage to other subjects and specialties, and the integration of didactic methods facilitate the local implementation of the learning objectives without loosing any academic freedom.

[Autologous chondrocyte transplantation in the ankle joint. Rational or irrational?]. / Autologe Chondrozytentransplantation am oberen Sprunggelenk. Rational oder irrational?

Ankle sprains are one the most common injuries of the lower limb. Fractures, ligamentous lesions, and cartilaginous damage are often associated. Nevertheless the injury is often misjudged and concomitant chondral lesions are assessed late. In the case of a symptomatic osteocartilaginous lesion of the talus, which can be illustrated by MRI or X-ray, operative intervention is indicated. Methods such as microfracturing, mosaicplasty, and autologous chondrocyte transplantation (ACT) are in clinical use. The latter is well known and being established as the treatment of choice for large cartilage defects in the knee. Due to the good results in the knee and the technological improvements (three-dimensional tissue constructs seeded with autologous chondrocytes) this method is being increasingly applied for cartilage lesions of the talus. In contrast to the mosaicplasty donor site morbidity is low and the size of the defect is not a limiting factor. The current studies about ACT of the talus show a stable repair of the defect with mostly hyaline-like cartilage and high patient satisfaction. Therefore, the procedure can be recommended for lesions>1 cm2. Concomitant treatment of posttraumatic deformities (malalignment), ligamentous instabilities, and especially the reconstruction of bony defects are compulsory.

Proprioceptive skills and functional outcome after anterior cruciate ligament reconstruction with a bone-tendon-bone graft.

Several studies have shown that patients with anterior cruciate ligament (ACL) reconstruction have an improved proprioceptive function compared to subjects with ACL-deficient knees. The measurement of functional scores and proprioception potentially provides clinicians with more information on the status of the ACL-reconstructed knees. To evaluate proprioception in patients following ACL reconstruction with a bone-tendon-bone (BTB) graft, we used the angle reproduction in the sitting, lying and standing positions and the one-leg hop test. Forty-five patients between 19 and 52 years of age were investigated in a 36-month period after the operation. For functional performance measurement, the International Knee Documentation Committee (IKDC) score was used. Very good and good results were seen in 95% of cases. All patients returned to the same activity level as seen before ACL repair. There was a significant difference in the active angle reproduction test between the ACL-reconstructed knees and normal knees in the active sitting position. Tests with passive angle adjustment in the sitting, lying and active standing positions did not show any differences in proprioceptive skills. Good to very good results in the one-leg hop test we found in 95% of patients. After ACL reconstruction, deficiencies in the active angle reproduction test were very small but, nevertheless, were still observed. Overall, the functional and proprioceptive outcomes demonstrate results to recommend the procedure.

[Radiological and clinical functional examinations 36 months after anterior cruciate ligament repair by a patellar tendon graft]. / Radiologische und klinisch funktionelle Untersuchung 36 Monate nach vorderer Kreuzbandplastik mittels Patellarsehnentransplantat.

AIM: The aim of this study was to examine radiological and functional outcome measurements after anterior cruciate ligament (ACL) reconstruction with a bone-tendon-bone (BTB) graft. Investigations included assessment of bony integration conditions regarding the use of bioabsorbable cross pins or a lateral screw for femoral graft fixation. A description of radiological parameters in contrast with IKDC findings is also given. METHOD: After ACL injuries, 45 patients underwent an ACL repair. For tibial tunnel placement the tibial guide was used in full knee extension. A size-specific femoral aimer was placed by using the transtibial technique in the "over the top" position and the tunnel was reamed with the acorn reamer to 30 mm depth. In 15 patients the BTB graft was fixed with a titanium blunt nose screw from the lateral aspect. The cross-pin technique with bioabsorbable RIGIDFIX implants was used in 30 patients. All patients underwent a follow-up study 36 month postoperatively. Geometric tests of digitised X-rays were performed. For clinical and functional outcome studies of ACL repairs the IKDC score is widely accepted. The score was modified into numeric parameters for 15 selected groups of the IKDC score. All 15 categories were rated from 1 to 4 points (Category A = 4, B = 3, C = 2, D = 1). Clinical and radiological results were statistically analysed. RESULTS: According to the literature, tunnel placement tibial was physiological in 91% and femoral in 93% of the cases. The femoral tunnel was completely invisible in all patients. No necrosis or pathological findings in former pin holes were seen. In 24 patients the medial compartment space was smaller, but less than 50 % compared to intraoperative X-rays. Even if the mean of tibial tunnel widening was 2.65 mm it was statistically not connected to the results of the IKDC score or X-ray findings of the femoral tunnel. Results in the IKDC groups and categories were seen to be in accord with overall very good and good outcomes. The modified IKDC score showed a mean of 55 points with a range from 46 as lowest (1 patient) and 60 in 4 patients (9%) as highest numeric score. CONCLUSION: Lateral femoral fixation with screws or bioabsorbable cross-pins shows a biological bony incorporation of a BTB graft. Tibial tunnel widening was seen but without any functional effects. Overall radiological and functional outcomes based on the IKDC score demonstrate results in favour of ACL reconstruction with BTB grafts. Due to the narrowing of the medial compartment space, more radiological outcome studies with a special emphasis on degenerative aspects have to be done.

[Intra-articular pain during gonarthrosis: a case report about an extremely increased cathepsin expression in chondrocytes]. / Intraartikulärer Schmerz bei Gonarthrose: Ein Fallbericht über eine stark erhöhte Expression der Cathepsine in Chondrozyten.

AIM AND BACKGROUND: Cysteine proteases as cathepsins K and L as well as matrix metalloproteases are considered to be basically involved in collagen turnover. Degenerative joint diseases such as gonarthrosis are characterised by massive cartilage degradation mediated by increased activities of these proteases. These enzymes are, therefore, interesting targets for the treatment of painful arthritic joint diseases. The aim of these studies was to reconsider the hypothesis that cathepsin activities are enhanced in patients suffering from osteoarthritis. METHOD AND RESULTS: We report on a 69-year-old female suffering from severe pain due to predominant retropatellar arthrosis. The clinical symptoms of this patient did not significantly differ from that of 30 other patients who were involved in this study. All patients undergone an endoprosthetic knee joint replacement. During the operation we harvested cartilage probes and isolated the chondrocytes from the joint cartilage for determination of the mRNA and the activities of cathepsins B, H, K and L. Compared to chondrocytes isolated from the control patients we found the activity of cysteine proteases to be extremely enhanced in chondrocytes of this patient. Moreover, the concentration of cystatin c, an endogenous inhibitor of cathepsins, was not detectable. CONCLUSION: The results raise doubts on the predominant role of cysteine proteases in severe cartilage destruction.

[Autologous chondrocyte transplantation by the sandwich technique. A salvage procedure for osteochondritis dissecans of the knee]. / Autologe Chondrozytentransplantation (ACT) in "Sandwich"-Technik. Rückzugsmöglichkeit bei der Osteochondrosis dissecans genu.

The case presented is that of a 23-year-old man suffering from osteochonditis dissecans (OCD) of the medial femoral condyle, in whom a free piece of cartilage had separated off and there was a large osteochondral defect despite numerous operations. After refixation of the fragment failed, an autologous chondrocyte transplantation (ACT) was performed using the sandwich technique. Three years after the operation the patient is very satisfied with the result. The radiological findings show stable repair of the bony and cartilaginous defect area. This case report shows that ACT is a valid method for the treatment of large osteochondral defects even after several previous failed operations. The low donor site morbidity is an important advantage over other methods, such as transplantation of osteochondral plugs.

[The subacromial impingement syndrome]. / Das subakromiale Impingementsyndrom.

The subacromial impingement syndrome describes the pathological contact between the rotatory cuff and the acromion. It is only a symptom and not a generic term for the different pathological diseases of the subacromial region. It is the diagnostical aim to verify the pathogenesis of the impingement syndromes and it is essential to differentiate structural versus functional causes. The diagnosis "impingement syndrome" should not have an acromioplastic procedure as general consequence. Because the expression "impingement syndrome" does not show causal approach it should no longer be used as a diagnosis. The term subacromial syndrome, in conjunction with the underlying pathological cause, acquires more therapeutic and prognostic clarity.

[Transgluteal mini-incision. Technique and our own results]. / Transgluteale Miniinzision : Technik und eigene Resultate.

BACKGROUND: A transgluteal mini-incision technique according to the approach of Bauer et al. is described. MATERIAL AND METHODS: Altogether 194 patients were supplied with a cementless primary total hip endoprosthesis using this approach. Our own results regarding ASA, body mass index, operation time, transfusions, the course of the Hb values, and the use of drugs against pain are described. RESULTS: The approach does not show any dependence on ASA and BMI. Operation time, blood loss, and use of drugs against pain are not influenced by it. Angled reamers and impactors are mandatory to prevent additional damage of soft tissue. The cosmetic benefit seems to be the only advantage. The approach cannot be recommended for general use.

Press fit fixation of cementless cups: how much stability do we need indeed?

INTRODUCTION: Using screws for a better primary and secondary fixation has been discussed in the literature of the recent years, although the principle of press fit has been explained as the principle of a push-button. The authors wanted to compare their own results in patients using X-rays from the postoperative course to decide if it is really safer to use screws or not. MATERIALS AND METHODS: Two hundred and twenty one consecutive, not selected patients were treated with total hip arthroplasty using a cementless cup type Duraloc. They were followed up over a time of 5 years for radiological changes of the bony acetabulum around the cup ("acetabular zones" according to De Lee and Charnley). One hundred and ten cups were additionally fixed with one to three screws at the upper part in region C1, 101 cups were implanted without the use of screws. RESULTS: Periprosthetic changes visible on the radiographs (immediate postoperative gaps, subsequent sclerosis and radiolucent lines) were assessed according to the time of their appearance. A gap in zone C2 was seen more often immediately after operation within the group without screws (17.8% vs. 7.3%) and disappeared within the following 25 months. Within the group with screws significantly more often a gap was found in zone C1 and C3 compared to the group without screws (7.3% vs. 1.9%). In the group with screws a sclerosis of the bone in zone C1 developed in 32.7% mostly within the first 5 months. It was followed by a radiolucent line in zone C3 in 28.2% mainly within 5-25 months postoperatively and in zone C1 in 20.9% within 16 months. Significantly less seldom were these phenomena seen at the cups without screw fixation. There was no correlation between lateral or medial positioning and deviations from the ideal inclination to the bony changes around the cups. No signs of loosening occurred in either group. CONCLUSION: Less radiological changes around the cup if no screws were used and no disadvantages within this group led to the conclusion that an additional screw fixation in principle is not necessary in press-fit cups.

Osteointegration of hydroxyapatite-titanium implants coated with nonglycosylated recombinant human bone morphogenetic protein-2 (BMP-2) in aged sheep.

Osteointegration of metal implants into aged organisms can be severely compromised due to reduced healing capacity of bone, lack of precursor cells for new bone formation, or osteoporosis. Here, we report on successful implant healing in a novel model of aged sheep in the presence of nonglycosylated bone morphogenetic protein 2 (BMP-2). Ewes of 8 to 12 years with significant radiologic and histologic signs of osteoporosis and adipocytic bone marrow received a cylindrical hydroxyapatite-titanium implant of 12 x 10 mm. BMP-2 has been produced as a bacterial recombinant fusion protein with maltose-binding protein and in vitro generation of mature BMP-2 by renaturation and proteolytic cleavage. A BMP-2 inhibition ELISA was developed to measure the in vitro release kinetics of bioactive human BMP-2 from immersed solid implant materials by using Escherichia coli expressed and biotinylated recombinant human BMP-2 receptor IA extracellular domain (ALK-3 ECD). The implants were placed laterally below both tibial plateaus, with the left leg implant carrying 380 microg BMP-2. Both implant types became integrated within the following 20 weeks. The control implant only integrated at the cortical bone, and little new bone formation was found within the pre-existing trabecular bone or the marrow cavity. Marrow fat tissue was partially replaced by unspecific connective tissue. In contrast, BMP-2-coated implants initiated significant new bone formation, initially in trabecular arrangements to be replaced by cortical-like bone after 20 weeks. The new bone was oriented towards the cylinder. Highly viable bone marrow appeared and filled the lacunar structures of the new bone. In mechanical tests, the BMP-2-coated implants displayed in average 50% higher stability. This animal model provided first evidence that application of nonglycosylated BMP-2 coated on solid implants may foster bone healing and regeneration even in aged-compromised individuals.

[Metatarsalgia. Differential diagnosis and therapeutic algorithm]. / Metatarsalgie. Differenzialdiagnose und Therapie.

Metatarsalgia is explained as localized or more diffuse tenderness beneath the metatarsal heads. The pain may be attributed to various etiologies. Pathological changes affecting the positional relationship of the metatarsals in the sagittal plane can cause increased pressure and friction forces during weight bearing. Since the length of the metatarsals displays a wide range of disparity only a few pathological settings, i.e., brachymetatarsia, require surgical correction. Beside those disorders of positional relationship, metatarsalgia may be due to lesser toe deformities, osteonecrosis of a lesser metatarsal head (Koehler's disease), and neurological disorders (Morton's neuroma). Apart from the etiology increased load, which is transferred to the central metatarsals, can be treated successfully with orthotic devices. If conservative measures fail, surgical treatment can be indicated. Prior to any operative therapy it is mandatory to perform a detailed analysis of the underlying pathology to avoid persistent pain or recurrence of the deformity.

[The acquired buckling-flatfoot. A foot deformity due to obesity?]. / Der erworbene Knick-Plattfuss Eine Fussdeformität des Ubergewichtigen?

Flatfoot deformity is characterized by a multiplanar hindfoot malalignment. Although the etiology remains unclear, the deformity is mainly attributed to ligamentous laxity and dysfunction of the posterior tibial tendon. Obesity is thought to be a risk factor that additionally impairs hindfoot stability. Performing a retrospective clinical and radiological study, we compared two groups, each with 75 patients. One group included patients with a flatfoot deformity stage 2, while the other group showed no hindfoot malalignment. Reviewing the weight and calculating the body mass index revealed significantly increased values for those patients with flatfoot deformity (P=0.034 and P>0.001, respectively). This correlation should be considered during the decision-making process on surgical strategies. In obese patients with flatfoot deformity, stage 2 soft tissue reconstruction and hindfoot osteotomies should be combined with hindfoot arthrodeses, i.e. subtalar fusion, to maintain sufficient and durable stability.

Prophylaxis of heterotopic bone formation by radiotherapy -- a comparison between pre- and postsurgical activity.

INTRODUCTION: Heterotopic bone formation after total hip replacement is estimated to occur in about 30% of all patients. It may develop into restriction of mobility and persisting pain. MATERIAL AND METHODS: From 1991 to 1998, 90 patients with uncemented total hip replacement and known risks to develop heterotopic bone formation were treated by radiotherapy (14 patients received 5 x 3 gy between the first and the fifth postoperative day, 13 patients received 1 x 7 gy between 24 hours postoperative, 63 Patients received 1 x 7 gy between 24 hours preoperative) using gamma ray or high-energy photons. The distance between radiation and surgical procedure was never more than 24 hours. Clinical and radiological assessment was carried out 3, 6 and 12 month after surgery. RESULTS: Independent of the method of radiotherapy no clinically relevant ossification was noticed on the follow up in any of the 90 patients. CONCLUSION: The results of this study show the efficiency of radiotherapy in the prophylaxis of heterotopic bone formation, independent of the three applied methods. It seems to be important, that the interval between radiation and surgery is not longer than 24 hours. Because of possible risks and logistic problems preoperative radiation should be preferred over postsurgical treatment.

Radiological changes around the stem after cementless hip implantation in case of the anatomic medullary locking hip system -- five years results.

INTRODUCTION: We present radiological results regarding the development of stress shielding around the stem of the AML hip endoprosthesis and discuss the clinical significance of it and preventive measures against stress shielding. MATERIAL AND METHODS: 391 patients (216 female and 122 male) with an AML-hip-endoprosthesis between 1991 and 1992 were followed clinically and radiologically during 5 years postoperatively. It was searched for a statistical correlation of stress shielding with a pre-existing osteoporosis of the proximal femur (Barnett-Nordin index), the diameter of the stem, a varus position of the stem and thigh pain. RESULTS: Stress shielding occurred in only 13.5 % of all patients. Atrophy of the proximal femur was detectable within 1 year, in 5 cases already after 3 weeks. Distal sclerosis reached its maximum after 1-2 years. Remarkably, women showed a tendency to more frequent stress shielding. In women more often than in men, a pre-existing osteoporosis of the proximal femur occurred. Cases with osteoporosis of the proximal femur experienced more often stress shielding. The same was seen in prostheses with diameters >13.5 mm. A slight varus position of the stem also favoured stress shielding, but it indicated an incomplete canal fit of the stems, too. Patients with stress shielding more often were suffered from thigh pain. CONCLUSION: Stress shielding is a result of the discrepancy between the elasticity of the bony femur and the stiffness of the stem. The AML-hip-prosthesis rarely shows this phenomenon. An osteoporosis of the proximal femur (coupled with an thinning of the cortex and generating higher elasticity of the bone), stems with higher diameters (what means higher stiffness) and incomplete canal fit more likely predisposed patients to stress shielding. To prevent stress shielding, the AML prosthesis should not be implanted in cases with known severe osteoporosis of the proximal femur. This prosthesis should be taken preferable in cases with diameters of the femoral canal smaller than 15 mm. Fully canal fit has to be achieved. The frequency of thigh pain, which occurs more often in patients with stress shielding, could be reduced by considering those factors.

[Periprosthetic bone loss after total hip endoprosthesis. Dependence on the type of prosthesis and preoperative bone configuration]. / Verlauf der periprothetischen Knochendichte nach Hüfttotalendoprothesenimplantation. Abhängigkeit von Prothesentyp und knöcherner Ausgangssituation.

The changes of the periprosthetic bone density were examined with DEXA in 81 patients over a period of 1 year after implantation of cementless total hip endoprosthesis. Four types of endoprostheses (Vision 2000/Duraloc, ALPHA-Fit/ALPHA-Lock Plus, CLS/Allofit, Mayo/Trilogy) were implanted. Information on the changes of the periprosthetic bone density depending on the type of the prosthesis and the bony situation at the femur before operation was expected from these measurements. In all types of stems the strongest reduction of the bone density was found in the region of the calcar femoris, and the smallest changes were found distally and medially of the tip of the prostheses. In the prosthesis with shorter stem the change of the bone density was altogether clearly lower than in prostheses with longer stem. With increasing size of the prosthesis with proximally porous coating made from cobalt-chrome alloy, proximal atrophy was observed more frequently, whilst in the prosthesis made from titanium alloy with completely rough-blasted surface the distal hypertrophy increased. A low preoperative corticalis-bone marrow index strengthened the proximal atrophy in proximally porously coated prosthesis made from cobalt-chrome alloy and led in the prosthesis with completely rough-blasted surface more often to distal hypertrophy of the bone.

Overwhelming septic infection with a multi-resistant Staphylococcus aureus (MRSA) after total knee replacement.

INTRODUCTION: The incidence of early deep infection after arthroplasty of the knee is very low but could represent a serious future problem. MATERIAL AND METHODS: The authors report on a 71-year-old woman with gonarthritis who was supplied with a total knee endoprosthesis and developed a local infection followed by septic shock. RESULTS: The infection was evidently caused by a multiresistant Staphylococcus aureus (Staph. aureus). The primary clinical signs closely resembled a necrotizing fasciitis. Systemic and local application of vancomycin led to an improvement of the symptoms at secondary sites, but only the amputation of the primarily infected leg was lifesaving. CONCLUSION: In order to prevent such events, the authors recommend a number of additional presurgical measures. Firstly, a swab from the nose and throat should be taken prior to an elective surgery in patients with elevated risk of immunodeficiency, for example in patients with diabetes. The diabetes should be adequately treated before an elective operation is undertaken. Secondly, an early punction of the knee joint should be carried out if there is any doubt regarding inflammation. Isolated infectious agents should be grounds for early revision, which should always be completed with a rinsing procedure and with adequate antibiotics. Immunotherapy should be taken into consideration. Antiepidemic measures are recommended in cases with known Staph. aureus.