[ACL reconstruction in skeletally immature patients]. / Ersatz des vorderen Kreuzbandes bei Kindern und Jugendlichen mit offenen Wachstumsfugen.

AIM: The treatment of choice for skeletally immature patients with anterior cruciate ligament (ACL) deficiency is an ACL reconstruction. In a retrospective study we analysed the clinical results after ACL reconstruction in skeletally immature patients. MATERIAL AND METHOD: In 55 immature patients the ACL was replaced with a four strand-hamstring graft in an anatomic transepiphyseal origin. The fixation was by means of an extracortical button femoral and a suture washer or staple tibial. Patient mean age at operation was 13 years (8 to 16 years). RESULTS: The mean follow-up was at 3.2 years (1 to 7.5 years) postoperatively. The objective IKDC 2000 score was 90.7 % normal or almost normal values. The mean Lysholm score was 94.1 points (70 - 100), the mean Cincinnati knee score was 93.9 points (76 - 100) and 88 % of the patients went back to normal or almost normal sports according to the Tegner score. Stability testing performed with the KT-1000 arthrometer was 1.0 mm (0 - 4 mm) (preoperative average 5.8 mm). The traumatic re-rupture rate was 5.5 %. In two additional cases a partial rupture of the graft was analysed by arthroscopy. Growth deformities or leg length differences were not seen in any case. CONCLUSION: ACL reconstruction with hamstrings and extracortical fixation showed good results and might be the treatment of choice in immature patients. The complication rate was low and there were no postoperative growth deformities.

[ACL reconstruction in skeletally immature patients]. / Ersatz des vorderen Kreuzbandes bei Kindern und Jugendlichen mit offenen Wachstumsfugen.

AIM: The treatment of choice for skeletally immature patients with anterior cruciate ligament (ACL) deficiency is an ACL reconstruction. In a retrospective study we analysed the clinical results after ACL reconstruction in skeletally immature patients. MATERIAL AND METHOD: In 55 immature patients the ACL was replaced with a four strand-hamstring graft in an anatomic transepiphyseal origin. The fixation was by means of an extracortical button femoral and a suture washer or staple tibial. Patient mean age at operation was 13 years (8 to 16 years). RESULTS: The mean follow-up was at 3.2 years (1 to 7.5 years) postoperatively. The objective IKDC 2000 score was 90.7 % normal or almost normal values. The mean Lysholm score was 94.1 points (70-100), the mean Cincinnati knee score was 93.9 points (76-100) and 88 % of the patients went back to normal or almost normal sports according to the Tegner score. Stability testing performed with the KT-1000 arthrometer was 1.0 mm (0-4 mm) (preoperative average 5.8 mm). The traumatic re-rupture rate was 5.5 %. In two additional cases a partial rupture of the graft was analysed by arthroscopy. Growth deformities or leg length differences were not seen in any case. CONCLUSION: ACL reconstruction with hamstrings and extracortical fixation showed good results and might be the treatment of choice in immature patients. The complication rate was low and there were no postoperative growth deformities.

[Differences in taxation between medical care centers and conventional medical practices]. / Unterschiede in der Besteuerung von Medizinischen Versorgungszentren und Arztpraxen.

With the introduction of "Medizinisches Versorgungszentrum", a new medical provider was established in the German health sector as a competitor to conventional medical practices. With regard to the various legal forms, there are differences concerning taxation. This article examines these differences for the limited company and the civil law association.

Polyethylene particle-induced bone resorption in substance P-deficient mice.

Aseptic loosening is the major cause of total joint replacement failure. Substance P (SP) is a neurotransmitter richly distributed in sensory nerve fibers, bone, and bone-related tissue. The purpose of this study was to investigate the potential impact of SP on bone metabolism in polyethylene particle-induced osteolysis. We utilized the murine calvarial osteolysis model based on ultrahigh molecular weight polyethylene (UHMWPE) particles in 14 wild-type mice (C57BL/J6) and 14 SP-deficient mice. Group 1 (C57BL/J 6) and group 3 (SP-knockout) received sham surgery, and group 2 (C57BL/J6) and group 4 (SP-knockout) were treated with polyethylene particles. Analytical methods included three-dimensional micro-computed tomographic (micro-CT) analysis and histomorphometry. Bone resorption was measured within the midline suture. The number of osteoclasts was determined by counting the tartrate-resistant acid phosphatase-positive cells. UHMWPE-particle treated SP-deficient mice showed significantly reduced osteolysis compared to wild-type mice, as confirmed by histomorphometry (P < 0.001) and micro-CT (P = 0.035). Osteoclast numbers were significantly reduced in groups 3 and 4 compared to groups 1 and 2 (P < 0.001). Unexpectedly, SP-deficient mice (group 3) showed a significantly increased absolute bone mass compared to wild-type mice (group 1) (P = 0.02). The findings of our murine calvaria model lead to the assumption that SP is a promoter in particle-induced osteolysis. The pathophysiology of aseptic loosening is complex, and neuropeptides are not solely responsible for the progress of implant loosening; however, we conclude that there could be coherence between neurotransmitters and particle-induced osteolysis in patients with aseptic loosening.

[Arthroscopy-assisted glenohumeral arthrodesis: a case of uncontrollable shoulder instability]. / Arthroskopisch assistierte Arthrodese des Glenohumeralgelenks: Fall einer nichtbeherrschbaren Schulterinstabilität.

The promising option of arthroscopy-assisted glenohumeral arthrodesis to treat shoulder instability is presented. Compared with open arthrodesis of the shoulder, especially the cosmetic result of this procedure is better. Clinical follow-up revealed that in addition to pain reduction there was an improvement in the shoulder function as assessed according to the Constant and Murley scores. Evaluation of the DASH questionnaire and the Sf-36 health questionnaire clearly showed the improved function of the arm as well as the positive effect on the patients' general state of health.

[Endosteal reaction in the region surrounding the stem of a cement-free prosthesis. An early radiological sign of imminent fracture of the femoral shaft?]. / Endostale Reaktion im Schaftbereich einer zementfreien Prothese. Ein radiologisches Frühzeichen einer drohenden Femurschaftfraktur?

Periprosthetic fractures are familiar complications after total hip arthroplasty and have often been reported in the literature. The most frequent localization of such fractures is the middle third of the shaft. In the case described here a minor trauma resulted in a periprosthetic fracture with fracture of the femur and of the femoral component of a Lord prosthesis. A radiograph taken prior to trauma showed an endosteal reaction at the level at which the fracture later occurred. This might have been an indication that the stem of the prosthesis was already broken; had this radiological sign been correctly interpreted, it is possible that the fracture could have been avoided.

[Rotating platform spinout in LCS knee arthroplasty]. / Spinout der rotierenden Plattform bei der LCS-Knieendoprothese.

In knee arthroplasty, a lax flexion gap may cause flexion instability. Subsequently, the operated knee may subluxate or dislocate. We report on a case of recurrent subluxations with malrotation of the rotating platform (spinout) after primary LCS total knee arthroplasty. Potential causes for spinout, therapy procedures, and consequences for the primary surgical technique are discussed. In the LCS rotating platform knee arthroplasty, the flexion gap must not be laxer than the extension gap. In such an instance, we recommend a higher rotating platform and a more proximal distal transverse femoral osteotomy.

[Structural femoral head allografts in revision surgery of loosened acetabular cups]. / Strukturelle Femurkopfallografts in der Revisionschirugie von gelockerten Hüftendoprothesenpfannen.

BACKGROUND: Treatment of acetabular bone defects presents a great challenge in revision total hip arthroplasty (THA). Many methods of acetabular reconstruction have been described. The purpose of this study was to evaluate the midterm results of structural femoral head allografts for acetabular reconstruction. METHODS: Thirty-six patients (33 females and 3 males) with acetabular defects ranging from type 2C to type 3B according to Paprosky's classification were included in the study. In all cases acetabular defects were closed using allografts from femoral heads. In 13 cases an uncemented press-fit cup, in 17 cases a cemented polyethylene socket, and in 6 cases a Burch-Schneider antiprotrusion cage was implanted. The mean follow-up period was 84.2 months (range: 5-147). RESULTS: Four acetabular components failed. All 36 grafts were osseointegrated radiographically and formed a mechanically stable construction. The mean Harris Hip Score at the most recent follow-up was 79.8 points. The distance from the obturator line to the prosthesis head center was 3.73 cm (1.17-5.80 cm) preoperatively and 2.79 cm (0.85-4.8 cm) postoperatively (p<0.05). The distance from the teardrop figure to the prosthesis head center was 3.02 cm (1.0-5.8 cm) preoperatively and 3.25 cm (1.6-4.8 cm) postoperatively (p<0.001). CONCLUSIONS: Closure of acetabular defects of types 2C to 3B according to Paprosky's classification can be satisfactorily accomplished using femoral head allografts. These allografts may facilitate future revision surgery. Femoral heads are readily available due to widespread primary total hip replacement surgery. However, the use of structural femoral head allografts for acetabular reconstruction is cost intensive. Individual patient-related aspects, such as the function of revision arthroplasty, have to be considered when planning revision arthroplasty using femoral head allografts.

Reinforcement of deficient femur with inlay strut grafts in revision hip arthroplasty: a small series.

Failure of the femoral component due to severe loss of femoral bone is an important long-term complication of total hip arthroplasty. We treated four patients with a type IV femoral defect (Paprosky classification) because of aseptic and septic loosening. To enhance bone stock and create a stable prosthetic reconstruction we used femoral allografts as inlay strut grafts alone or combined with onlay strut grafts and impaction grafting. At a mean follow-up of 11 years all four patients presented good or excellent results with Harris Hip Score between 86 and 95 points. Radiologically, no migration of the stems were found and the struts showed signs of incorporation. Inlay strut grafts are a reliable method for bone reconstruction of deficient femoral bone stock in failed total hip replacement.

[Influence of the x-ray technique on evaluation of cup anteversion after total hip arthroplasty]. / Einfluss der Röntgentechnik auf die Beurteilung der Pfannenanteversion nach totaler Hüftendoprothetik.

AIM: Total hip arthroplasty (THA) is a standard procedure in orthopaedic surgery. Planar radiography of the implant is routinely performed to ensure that the operation has achieved the desired result. This study investigates the influence of varying the X-ray beam on the analysis of the radiograph. METHOD: Twenty-three patients were analysed after implantation of a total hip replacement. Besides a CT scan of the pelvis, symphysis- and hip-centred radiographs were available. The cup anteversion was calculated using two published algorithms. The CT-based data were the gold standard. RESULTS: Our study revealed a significant major error in the analysis of the symphysis-centred radiographs when compared with the hip-centered radiographs. Widmer's algorithm showed a significant superiority over Pradhan's formula. CONCLUSION: The best approximation of the anteversion angle was achieved using Widmer's technique by centering the X-ray beam onto the hip.

[Effects of bisphosphonates in arthroplasty]. / Bisphosphonatwirkungen in der Endoprothetik.

AIM: This study presents an overview of the general effects of bisphosphonates and in particular of their effects on different problems in joint arthroplasty. METHOD: First the chemical properties are described, then the biological effects. It is already known that bisphosphonates have effects on orthopaedic diseases and an increasing number of studies are investigating what effects can be achieved in joint arthroplasty with these substances. RESULTS: The bisphosphonates group was derived from industrial pyrophosphate which is used to prevent calcification. Bisphosphonates inhibit bone mineralisation and resorption. Several direct and indirect mechanisms are responsible for these effects. The inhibition of bone resorption is used to benefit patients suffering from various diseases causing increased bone resorption. Treatment with bisphosphonates results in greater bone density and improved mechanical bone quality. Indications for this treatment include osteoporosis, tumour-associated osseo-destruction, fibrous dysplasia and Paget's disease. Recent studies have shown that osseo-integration of metal implants is accelerated and periprosthetic bone loss, which is caused by various different mechanisms during the lifetime of an implant, can be reduced. CONCLUSION: Bisphosphonates have been an established element in the treatment of bone metabolic disorders for many years. Their use in joint arthroplasty could become increasingly important.

[Localization of the neurokinin 1 receptor in hip joints of patients with painful osteoarthritis]. / Die Lokalisation des Neurokinin 1-Rezeptors im Hüftgelenk von Patienten mit schmerzhafter Osteoarthrose.

INTRODUCTION: Recent studies on osteoarthritis have focused on nociceptive substance P (SP) containing afferent nerve fibres. The effects of SP are known to be mainly mediated by the tachykinin receptor neurokinin 1 (NK1-R). AIM: The aim of the present study was to demonstrate the NK1-R in human joint tissues. METHODS: The hip joint capsule of three patients with painful hip osteoarthritis (Group 1), three patients with femoral neck fracture showing no cartilage destruction (Group 2, controls) and the soft tissue of the fossa acetabuli of Group 1 were resected during hip arthroplasty implantation. The tissue samples were cut into small blocks and immersion-fixed in Zamboni's fixative. The specimens were frozen, cut into 50 microm sections and immunostained using a standard immunohistochemical staining protocol. RESULTS: In Groups 1 and 2 the NK1-receptor was localised in the wall of venous vessels, on Schwann cells of nerve bundles and on nerve fibres. In the osteoarthritis group the staining pattern was similar but the number of NK1-bearing cell structures seemed to be enhanced. CONCLUSIONS: The present study provides the first evidence of NK1-R in the human hip joint. In patients with painful osteoarthritis the density of NK1-R-positive cell structures seemed to be increased. The localisation of the NK1 receptor on different cell types suggests multiple effects of SP in normal and osteoarthritic joints.

[A comparison of the antiresorptive effects of bisphosphonates and statins on polyethylene particle-induced osteolysis]. / Ein Vergleich der antiresorptiven Effekte von Bisphosphonaten und Statinen auf Polyethylenpartikel-induzierte Osteolysen.

An ongoing unraveling of the molecular mechanisms in aseptic loosening of hip arthroplasty has opened up novel potential pharmacological interventions. In this study the antiresorptive effects of the bisphosphonate zoledronate and the statin simvastatin on ultra high molecular weighted polyethylene (UHMWPE) particle-induced osteolysis were compared. Two previous studies of our group based on the murine calvarial model of UHWMPE particle-induced osteolysis were pooled to form four study groups. Animals in group I (n=14) underwent sham surgery only. In groups II (n=14), III (n=7) and IV (n=7) UHMWPE particles were implanted on the calvariae. Animals in groups III and IV were additionally treated with zoledronate (single 25 microg/kg s.c. injection) and simvastatin (120 mg/day p.o. for 14 days), respectively. After two weeks, calvaria were processed for undecalcified histomorphometry. Bone resorption was measured using Giemsa staining. Osteoclast numbers were determined using TRAP-staining. UHMWPE particle implantation resulted in a grossly pronounced osteolytic activity with significantly increased values of bone resorption (p < 0.001) and osteoclast numbers (p < 0.001). Additional treatment with zoledronate or simvastatin counteracted the particle-induced effects. A comparison of the two medical treatments revealed no statistically significant differences in bone resorption (p = 0.63) and osteoclast numbers (p = 0.41). A single dose of the bisphosphonate zoledronate decreased UHMWPE particle-induced osteolysis in a murine calvarial model as effectively as a daily treatment with simvastin. Both drug groups may have a preventive and therapeutic role as antiresorptive agents in wear particle-induced bone resorption following total joint replacement.

[Reconstruction of the tibial diaphysis with transfer of the tibial head onto the proximal fibula. Follow-up after 63 years]. / Rekonstruktion der Tibiadiaphyse mittels Tibiakopftransfer auf die proximale Fibula. Follow up nach 63 Jahren.

Osteoarthritis of the knee is often diagnosed in the orthopedic trauma practice. One major cause is axial deformity with overload. In the case presented here osteomyelitis of the tibial diaphysis developed in childhood. Surgical treatment consisted of resection of the middle tibial third and transferring the tibial head onto the proximal fibula. In this way it was possible to eradicate the osteomyelitis of the lower leg and to achieve osseous consolidation between the tibia and fibula. Despite the significant shortening of the lower limb and the varus axial deformity, the knee joint function was satisfactory in the subsequent development. After a long interval without symptoms the patient developed a medially accentuated osteoarthritis of the knee.

[Revision of failed acetabular cups with extensive structural allografts]. / Die Revision von gelockerten Hüftendoprothesenpfannen mit ausgedehnten strukturellen Allografts.

AIM: Structural allografts are used with encouraging results for revision of failed total hip arthroplasty and in the surgery of bone tumours. The aim of the present study is to describe the clinical and radiological results achieved with structural allografts in revision of a total hip arthroplasty. MATERIAL AND METHODS: 15 patients (12 female and 3 male patients) were revised with an acetabular defect situation of type 3 A or 3 B according to the Paprosky classification. Five fresh-frozen acetabula, nine distal femora and one proximal tibia were used for acetabular reconstruction. The rigid graft fixation was performed with 2 > or = AO screws. In one case a cemented acetabular ring was implanted, four cementless cups and ten cemented polyethylene acetabular components were used. The mean follow-up was 7.9 years (1.6-11.0 years). RESULTS: A stable osseointegration of fifteen transplanted structural allografts was achieved in thirteen cases. Two allografts (one aseptic loosening, one deep infection) failed to osseointegrate. In one case the migration of a cementless cup was registered. Revision surgery of this female patient was performed successfully with a cemented reconstruction ring. The mean Harris hip score at the latest follow-up was 81.4 points (70-99 points). CONCLUSION: For reconstruction of acetabular bone stock and restoration of the bone anatomy structural allografts can be recommended. The use of cementless cups in combination with structural grafts is to be evaluated as critical.

[Follow-up study after dynamic and static stabilisation of the lumbar spine]. / Follow-up-Studie nach dynamischer und statischer Stabilisierung der lumbalen Wirbelsäule.

INTRODUCTION: The clinical indication for graf's ligamentoplasty and dorsoventral fusion may be described as the "lumbar instability syndrome". A follow-up comparison between Graf's ligamentoplasty and instrumental dorsoventral fusion in a consecutive series of 52 patients was performed. METHODS: 52 patients operated on for low back pain were recalled for a clinical and radiological review (at mean 79 months postoperatively). 26 patients underwent Graf' ligamentoplasty and 26 patients underwent dorsoventral fusion. We evaluated the surgical results and measured an objective outcome using the Oswestry Score, Low Back Outcome Score (LBOS) and Visual Analogue Scale (VAS). For radiological evaluation the Mimura and the Pathria Scores were used. RESULTS: There was no statistically significant difference between the two groups, when measured by the Oswestry Score, LBOS and VAS at the latest follow-up. The difference between the preoperative and actual VAS in each group was statistically significant (p < 0.001). Furthermore, there was no provable preoperative parameter in favour of either one of these therapies. CONCLUSION: Both methods for stabilisation methods of the lumbar spine had a comparable clinical outcome.

Limited range of motion caused by heterotopic ossifications in primary total knee arthroplasty: a retrospective study of 27/191 cases.

INTRODUCTION: Heterotopic ossification (HO) following primary total knee arthroplasty is a rare complication and may be symptomatic if massive enough. Especially the range of motion (ROM) is essential for the function and durability of the implant. The aim of the study was to evaluate the influence of HO on ROM using clinical and radiological parameters. MATERIALS AND METHODS: We reviewed 191 primary total knee arthroplasties according to the clinical preoperative and postoperative parameters of the Knee Society Score with special interest paid to the ROM. Standardized radiographs were taken at three levels and the implant position compared. The patients were divided into group 1 (with HO) and group 2 (without HO). The clinical and radiological parameters were compared. RESULTS: We found an incidence of HO in 14.1% (n = 27). Group 1 showed a decreased ROM postoperatively (p = 0.003) and worse flexion contracture (p = 0.04) compared with group 2. The evaluated radiological parameters showed no significant difference between the two groups. CONCLUSION: We found a significant limitation of ROM because of HO in our study. We found no correlation between HO and component alignment or component position. Local irritation has to be considered the main reason for limited ROM.

[Spinal manipulative therapy and cervical artery dissections]. / Chirotherapie der Halswirbelsäule und Gefässdissektionen.

Severe complications after cervical spine manipulation are rare. As experts for medical treatment errors, we received between July 2002 and February 2004 cases with serious complications in the central nervous system after manipulation. 5 vertebral artery dissections with subsequent brain infarction were registered. In all cases, the patients showed complete persisting remission of symptoms. In addition, a kinematic estimation model was developed to study the possible causes of vertebral artery damage. We were able to demonstrate that material extension is dependent on cervical rotation and the "free length" of the vertebral artery in the upper cervical spine.

[AMC unicondylar prosthesis]. / Die AMC-Unikondylarprothese. Mittelfristige Ergebnisse und Erfahrungen mit der minimal-invasiven Technik.

Since its introduction in the 1970s, unicompartmental knee arthroplasty (UKA) has become a standardized routine technique. Increasing experience in determining the indication for UKA and improvements in design and materials of the prosthesis have led to better results. The AMC UKA has an unconstrained mobile bearing with congruent area contact from 0 degrees to 30 degrees of flexion. The principle is that a polyethylene mobile bearing, concavely spherical above and flat below, can maintain perfect congruity between the spherical metal femoral condyle and the flat metal tibial plateau. This ensures complete freedom to rotate and slide upon one other with physiologic kinematic and low intrinsic stability. The low contact stress results in reduced polyethylene wear. The 361 AMC UKA replacements of the current study showed safe anchorage of the prosthesis and good durability of the mobile bearings. The clinical results of the investigated patients demonstrate that the AMC UKA is a successful concept. The comparison of 30 minimally invasive UKA with 30 conventional UKA and 30 total knee replacements shows an advantage of the minimally invasive technique with regard to reduced rehabilitation time. The accuracy of implantation was comparable between the conventional and the minimally invasive techniques.