[Chronic ankle joint instability: in unrecognized distal rupture of the syndosmosis and malunion of the distal fibula]. / Chronische obere Sprunggelenkinstabilität : Bei nicht erkannter distaler Syndesmosenruptur und Malunion der Fibulaspitze.

BACKGROUND: It is often difficult in the acute phase to diagnose a lesion of the distal tibiofibular syndesmosis. If this lesion is overlooked, the patient will develop an incongruity of the upper ankle joint with a pathological external rotation of the talus. The risk of a possible premature arthritis is clearly increased. OBJECTIVES: In this case study a distal rupture of the syndesmosis in a young patient was overlooked in the initial diagnostic work-up. METHODS: A search of the relevant literature and a case report. RESULTS: In the case described the shortened fibula and chronic instability of the tibiofibular syndesmosis were repaired with a lengthening and derotational osteotomy and reconstruction using the gracilis muscle tendon. Through this method an exact reconstruction of the normal anatomy could be achieved. CONCLUSION: Posttraumatic misalignment in the ankle joint is associated with a high risk of secondary degenerative lesions. In cases with suspicion of a syndesmosis lesion, confirmation of the diagnosis is imperative so as to perform an anatomic repositioning and reconstruction of stability.

Design aspects and clinical performance of the thrust plate hip prosthesis.

The thrust plate hip prosthesis (TPP) was conceived to maintain the physiological stress distribution in the proximal femur so as to prevent bone atrophy in this region, often encountered after implantation of conventional stem-type prostheses. A thrust plate of TiAlNb is firmly fixed to the neck of the femur by means of a forged CoCrMo bolt introduced through the lateral cortex, just below the greater trochanter, and through the metaphysis. A boss that contains the bolt head rests on the lateral cortex. A proximal extension from the thrust plate terminates in the ball head of the hip joint. Bone remodelling causes the initial prestressing of the structure (primary stability) to decline, but full integration of the thrust plate with the underlying host bone affords secondary stability. A total of 102 TPPs were implanted in the Cantonal Hospital, Chur, Switzerland, from 1992 to 1999 in 84 patients. The TPP was selected particularly for patients of the younger age group (26-76). Through its ability to load the medial cortex of the proximal femur in a physiological manner, the cortical bone in this region is preserved. The mean Harris hip score is 97 points and the survival rate 98 per cent, 144 months post-operatively.

Trochleaplasty for recurrent patellar dislocation in association with trochlear dysplasia. A 4- to 14-year follow-up study.

We investigated the clinical and radiological outcome of trochleaplasty for recurrent patellar dislocation in association with trochlear dysplasia in 38 consecutive patients (45 knees) with a mean follow-up of 8.3 years (4 to 14). None had recurrence of dislocation after trochleaplasty. Post-operatively, patellofemoral pain, present pre-operatively in only 35 knees, became worse in 15 (33.4%), remained unchanged in four (8.8%) and improved in 22 (49%). Four knees which had no pain pre-operatively (8.8%) continued to have no pain. A total of 33 knees were available for radiological assessment. Post-operatively, all but two knees (93.9%) had correction of trochlear dysplasia radiologically but degenerative changes of the patellofemoral joint developed in 30% (10) of the knees. We conclude that recurrent patellar dislocation associated with trochlear dysplasia can be treated successfully by trochleaplasty, but the impact on patellofemoral pain and the development of patellofemoral osteoarthritis is less predictable. Overall, subjective patient satisfaction with restored patellofemoral stability after trochleaplasty appeared to outweigh its possible sequelae.

[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.

[Actual relevance of minimal invasive surgery in fracture treatment]. / Aktueller Stellenwert der minimal-invasiven Chirurgie bei der Frakturversorgung.

Minimal invasive osteosynthesis (MIO) should belong nowadays in the armentarium of each trauma surgeon. The tendency to minimize the invasivity of every operation is a logical development considering the goal of each surgeon to reduce the iatrogenic damage caused by the operation. The term 'MIO" stands for this criteria: Fracture zone not opened, reduction by indirect manoeuvres or percutaneously by joy-sticks, small approaches for the application of the implants, intraoperative assessment of the reduction by imaging (fluoroscopy, arthroscopy, endoscopy, etc.). Long time before the definition of "minimal invasive surgery" some technologies in trauma surgery as external fixator or intramedullary nailing already fulfilled these criteria. In the nineties of the 20th century first cases of percutaneously inserted plate osteosynthesis have been reported. This technique got a widespread acceptance under the term of MIPO (minimal invasive plate osteosynthesis) during the last five years, especially pushed with the new angular stable screw-plate systems (LISS, LCP). The main problem of the MIPO-technique is and remains the reduction (no direct manipulation possible) and their intraoperative assessment (no direct visualisation). The balance between the degree of invasivity and the achieved quality of reduction and stability is often difficult to define and must be related to several factors (localisation and type of fracture, local soft tissue conditions, quality of the bone, age and wishes of the patient, available implants, experience of the surgeon, etc.). New technologies as improved imaging, intraoperative navigation and percutaneous reduction tools will help to further reduce the invasivity of fracture surgery in the future.

[Arthroscopic surgery]. / Arthroskopische Operationen.

Although arthroscopy of the knee joint had already been reported during the 1930's, the general dissemination of this method first began in the 1970's. The main reason for the rapid dissemination of this method was especially the fact that in addition to diagnostics, therapeutic possibilities were recognized and immediately implemented. This meant that arthroscopy had great potential and was made well known since the surgery was minimally invasive. Today we can assume that the technological side of the arthroscopic method is very widely developed and new innovations only arise slowly. Innovations are mostly connected with new innovative operating techniques. Surgery of the knee joint was the dominant application of arthroscopy in the beginning. The method was quickly applied to other joints. Today there is practically no joint which is inaccessible to arthroscopy. From surgical and therapeutic perspectives, arthroscopy is most frequently used today for the knee joint, followed by the shoulder joint, ankle joint, elbow joint, hip joint as well as wrist joint. Arthroscopic surgery within the field of joint surgery is regarded as indispensable. This specific surgery needs corresponding ability and skill, which must be individually acquired. Arthroscopic surgery evidently depends on technology and accordingly requires a corresponding fully operational medical infrastructure and knowledge. The big advantage of arthroscopic surgery lies in the minimally invasive technique, which has reduced the primary postoperative mortality significantly. Therefore, with good indicators the patient has decisive advantages as well as good cost to benefit ratios.

Investigating the effect of remodelling signal type on the finite element based predictions of bone remodelling around the thrust plate prosthesis: a patient-specific comparison.

The resorption of bone in the human femur following total hip arthroplasty is recognized to be related to the loading in the bone surrounding the prosthesis. However, the precise nature of the mechanical signal that influences the biological remodelling activity of the bone is not completely understood. In this study, a validated finite element modelling methodology was combined with a numerical algorithm to simulate the biological changes over time. This was used to produce bone remodelling predictions for an implanted thrust plate prosthesis (Centerpulse Orthopedics Limited) in a patient specific bone model. The analysis was then repeated using different mechanical signals to drive the remodelling algorithm. The results of these simulations were then compared to the patient-specific clinical data, to distinguish which of the candidate signals produced predictions consistent with the clinical evidence. Good agreement was found for a range of strain energy based signals and also deviatoric remodelling signals. The results, however, did not support the use of compressive dilatational strain as a candidate remodelling signal.

Long-term results with the uncemented thrust plate prosthesis (TPP).

The long-term clinical results of a novel concept for total joint replacement called the Thrust Plate Prosthesis (TPP) are presented. Only a restricted number of patients were provided with this new prosthesis (115 at the Orthopedic Department, Canton Hospital, Chur, and 47 at the Department of Orthopedic Surgery, University of Zurich). All patients have undergone clinical and radiological follow-up covering a period from 1980 to 1991. The basic feature of the Thrust Plate Prosthesis is the direct load transfer to the medial cortical bone of the femoral neck, and this has been unchanged since 1978. Titanium alloy has been used since 1986. The good clinical and radiological results are confirmed by a histological examination of an 8-year-old implant: In the crucial area of load transfer newly formed bone can be seen in direct contact with the thrust plate without fibrous tissue in between. The clinical results and histological findings have confirmed the validity of the biomechanical principle of the TPP. The TPP is therefore to be considered a true alternative to the conventional hip prosthesis. In contrast to the conventional intramedullary anchored stem prosthesis the TPP requires the removal of a minimum amount of bone stock, which is certainly important in young patients.

[Cementless socket fixation based on the "press-fit" concept in total hip joint arthroplasty]. / Zementfrei pfannenverankerung nach dem "Press-Fit-Konzept" bei der Totalprothesen-Arthroplastik der Hüfte.

PURPOSE OF THE STUDY: The key problem of implant fixation in THR is stress distribution, i.e. load transmission between bone and implant. The closer the load transfer is to the original physiological situation, the easier the adaptation of the periprosthetic bone to the new biomechanical conditions after implantation of the cup and the safer is its longlasting fixation. The aims of the studies were 1) to get information about the physiological load transfer in the normal hip joint, 2) to get information about the load transfer between acetabulum and acetabular sockets and vice versa, 3) to measure the periacetabular pelvic bone deformation as the stimulator of the remodelling process (third stage of osseointegration) in the normal hip joint and in hip joints fitted with different acetabular cups, 4) to study the morphological stages of osseointegration of a non-cemented press-fit cup and to compare the morphological structure of the periacetabular bone with the biomechanical data obtained by the in vitro studies and finally, 5) to compare the clinical and radiological outcome of follow-up studies of the senior author's "Press-Fit cup" with the theoretical hypotheses according to the experimental observations. MATERIAL AND METHODS: Load transfer between the acetabular bone and the femoral head on one side and press-fit cups has been determined by strain gauge measurements, finite element studies, pressure sensitive Fuji prescale films, CT-osteoabsorptiometry and telemetric measurements. Periacetabular deformation has been measured by Imetric Markers. Osseointegration of the senior author's press-fit cup and, thus, the remodelling process of the bony structures adjacent to the cup have been studied in autopsy specimens of THRs which have been in situ for several years. RESULTS: Load transfer measurements have shown that the main load in the original acetabulum as well as in the acetabulum fitted with a press-fit cup is transmitted to the periphery, especially to the acetabular cortical rim whereas the subchondral bone is exposed to lower, predominantly meridional (tension) stresses. Direct measurements of the periacetabular deformation under load revealed an increase of the peripheral press-fit with increasing stability of a (oversized) press-fit cup. Both the normal as well as the acetabulum fitted with a non-cemented cup deforms in a postero-medial direction. The histo-morphology of the periacetabular bone of autopsy specimens showed excellent bony in- and ongrowth of a porous titanium coating (SULMESH) and bone formation, especially at the periphery in zone 1 and 3 according to DeLee and Charnley. CONCLUSION: The studies have shown that the subchondral bone plate of the acetabulum has very little supportive function for non-cemented press-fit cups. For the preparation of the acetabulum it is, therefore, more important to ream the sclerotic subchondral bone until there is a well vascularized, well bleeding bone bed to facilitate osseointegration of a non-cemented acetabular socket than to preserve the subchondral bone plate as is the case in cement fixation. A non-cemented press-fit socket must transmit load predominantly to the cortical bone of the acetabular rim. Therefore, a too far medial positioning of the cup, and therefore loosing contact to the cortical rim, must be avoided under all circumstances. The clinical experience with acetabular revisions and with conversions of hip arthrodeses into a THR (where there is no subchondral bone at all) have shown the superiority of a well vascularized over a sclerotic (even mechanically stronger) bone bed. Furthermore, it has been shown that the additional use of screws for fixation of an acetabular cup is not only unnecessary but can be deleterious and causes complications including osteolysis and aseptic loosening.

[After-care in surgical replacement of the ligaments of the knee joint]. / Nachbehandlung bei operativem Bandersatz am Kniegelenk.

Reconstructive surgery of ligamentous injuries of the Knee Joint is often associated with a considerable impairment of its integrity and requires a high standard of surgical technique. The postoperative course, aiming towards normal function, is demanding and bound to biomechanical and biological principles. It therefore has to be built up gradually and lasts basically 12 months - with an individual variety. Up to the 6th postoperative week the healing process is in the foreground. During the second phase, up to the 12th week careful rehabilitation is aimed to improve muscle strength, increase weight bearing and optimize mobility. In the third phase, from the 12th week on, the patient regains full strength, range of motion as well as coordination, and an integrated sport rehabilitation is started.

[Leg pain from the orthopedic viewpoint]. / Der Beinschmerz aus orthopädischer Sicht.

The purpose of this paper is to analyze the etiology of pain in the lower limb provoked by the locomotor apparatus. Vertebral, pseudoradicular, radicular syndromes, the hip pain including the acetabular rim syndrome, the generally localized knee and foot pain are discussed. Major symptoms and clinical findings necessary for an effective differential diagnosis of the lower limb pain are pointed out.

[Infected prosthesis of large joints]. / Die infizierte Prothese grosser Gelenke.

The problems related to infections of hip- and knee-prostheses are generally known. The aim of the operation- a mobile and painless joint is jeopardized. The best therapeutic measure has to be evaluated individually by a differentiated diagnostic procedure. The health condition of the patient, type and localization of the infection, bacteriology and resistance of the microbes as well as the biomechanical condition of the artificial hip joint and the trophic quality of bone and soft tissue play an important role. The different therapeutic concepts we can dispose of should take these factors into account, so that a successful healing may be expected in 80 to 90% of the cases.

[Palliative surgery for bone metastases]. / Palliative Chirurgie bei metastatischer Knochenkrankheit.

Advances in the treatment of patients who have bone metastases are an issue of high importance to the orthopaedic surgeon. Early diagnosis requires knowledge of the pathogenesis of bone metastases. A primary route of metastatic cells is via Batson's vertebral vein plexus. An understanding of the pathophysiology enables the surgeon to plan effective treatment. As many patients continue to survive for prolonged periods following the detection of bone metastases, it is important to plan treatment that relieves pain and is functional. In long bones non-operative treatment with radiotherapy, patient education to avoid excessive torsional loads and systemic chemotherapy or hormonal therapy as well as diphosphonates are utilized for small lesions with less than 25 percent of the cortical diameter. The indications for surgical treatment include lesions with elevated fracture risk according to Mirels score. Special emphasis is led on the surgical treatment of spinal metastasis. Early and effective treatment improves the remaining quality of life in patients with metastatic bone disease. However a firm knowledge of the pathogenesis and pathophysiology helps the clinician in making an early diagnosis. Nevertheless the orthopaedic surgeon must recognize the need to approach management of these patients from a multidisciplinary perspective in cooperation with the oncologist, radiotherapist, rehabilitation medicine specialist, radiologist, and pathologist. The cooperation among all members of the team will assure the best possible care for the patient who has metastatic bone disease.

[Epidemiology, treatment and long-term results of spinal fractures at a non-university affiliated central hospital with special reference to fractures of the lumbar spine]. / Epidemiologie, Behandlung und Langzeitergebnisse von Wirbelfrakturen am nicht universitären Zentrumsspital unter besonderer Beachtung der Lendenwirbelfrakturen.

In a retrospective study epidemiology, treatment, clinical and radiological results of 283 patients with spine fractures in a five-year period are presented. The operation rate ranges from 42% of the cervical to 9% of the thoracical and 24% of the lumbar spine. We found good radiological results concerning the correction of the wedge compression and the collapse of the lumbar vertebral body by fixation with an internal fixator. After a follow-up of 2-5 years nearly 80% of conservative as well as operative treated patients had more or less residual back pain. Because there is a correlation between the quantity of pain and the radiological dislocation, exact initial diagnosis, without overlooking an instability, and adequate conservative or operative treatment is very important.

[Replacement of the anterior cruciate ligament combined with valgization osteotomy of the tibia in incipient medial gonarthrosis with anterior cruciate ligament insufficiency]. / Vorderer Kreuzbandersatz mit Tibiavalgisations-osteotomie kombiniert bei beginnender medialer Gonarthrose mit vorderer Kreuzbandinsuffizienz.

In 7 patients with chronic, primarily anteromedial instability and incipient medial gonarthrosis a procedure combining valgization osteotomy of the tibia with anterior cruciate ligament replacement was employed. Postoperative examinations after observation periods of between 6 months and 5 years revealed that the results were good to very good, both subjectively and objectively. There was either no recurrence or a definite alleviation of knee joint pain present preoperatively. In view of the good results the authors now regard a combination of valgization osteotomy and anterior cruciate ligament replacement as the treatment of choice in cases with clear insufficiency of the anterior cruciate ligament and simultaneous incipient medial gonarthrosis. The combined procedure improves chances of achieving the goal of therapy. A valgization osteotomy or an anterior cruciate ligament replacement alone ought to be regarded as inadequate treatment in such cases, especially in the longer term.

Cementless press-fit cup. Principles, experimental data, and three-year follow-up study.

The concept of the press-fit cup includes an operative defect as small as possible, achievement of intrinsic stability by press-fit, and surface coating by an orderly, oriented wire mesh coating. The design is a modified hemisphere with flattening in the pole area and oversized cup diameter. A first series of press-fit cups were fitted with titanium nitride-coated stainless steel mesh. The manufacturing of such chemically pure titanium has only recently become feasible. Animal experiments using mountain sheep have shown an increase in the stability of the press-fit cup within the acetabulum with time and progressive bony ingrowth; this was verified in cups retrieved at autopsy. Three hundred eighty-seven first-generation titanium nitride-coated stainless steel mesh implants have been reviewed with a follow-up time of 12 to 39 months (average, 16.6 months). There were no intraoperative complications related to the cup. The roentgenographic follow-up study of 330 (85.1%) hips showed only a single case with a radiolucent line in all zones (1-3) as a roentgenographic sign of loosening, i.e., fibrous ingrowth. Two cups had to be revised due to insufficient primary stability and tilting.

[Post-traumatic osteitis. The acute infection]. / Posttraumatische Osteitis. Der akute Infekt.

The acute infection is defined as bacterial growth within the surgical wound, that may occur within days to weeks after initial surgery but before bone union. The chances of complete recovery after an acute soft tissue inflammation are closely related to the interval between initial surgery and first signs of infection, the early recognition of the complication, the type of bacteria involved and the therapeutic measures. The first symptoms of an impending infection are the classical clinical ones of any inflammation: tenderness, swelling and reddening. All imaging procedures are of little or no value. The therapy consists of very aggressive and, if required, repeated wound revisions with debridement of all necrotic tissue, removal of loose bone fragments or loose implant material, wash-outs with antiseptic solutions (e.g. Taurolin) or even deposition of gentamycin beads. Systemic antibiotics may be added temporarily. The in- or external fixation devices must provide stable fracture fixation and the bone as well as the soft tissue envelope must be well vascularized.

[The temporal behavior of the anchorage of a cement-free implanted acetabular cup in animal experiments]. / Das zeitliche Verhalten der Verankerung einer zementfrei implantierten Hüftpfanne im Tierversuch.

The mechanical qualities of the cementless press-fit cup of a hip prosthesis were examined in sheep. Primary anchorage of the cup is achieved by relative oversize of the cup in relation to the acetabulum, causing a press-fit effect. The surface of the cup consists of Sulmesh, a titanium net, which allows bony ingrowth. The quality of the mechanical anchorage in the acetabular bone was tested by measurements of the torque and cranio-caudal tilting moment needed to pull out the cup. It was shown that the secondary biological anchorage of the press-fit cup exceeds the primary mechanical anchorage (measured in previous in vitro experiments) by a factor of three. This improvement of the mechanical fixation of the press-fit cup in the acetabular bone can be explained by bony ingrowth into the Sulmesh and can be confirmed by histological findings.

[Skeletal scintigraphy as early diagnostic aid in acute haematogenous osteomyelitis in the iliosacral joint (author's transl)]. / Skelettszintigraphie als Frühdiagnose bei der akuten hämatogenen Osteomyelitis im Iliosakralgelenk.

For the scintigraphic diagnosis of bone disease 99mTechnetium MDP has been shown to be of great value. In acute haematogenous pelvic ostemyelitis scintigraphy is one of the most important early diagnostic aids. The rare and difficult diagnosis with an initial negative X-ray can be confirmed by a high uptake on scintigraphy. Through early selected antibiotic therapy in high doses the development of radiologic changes were prevented which is shown in the two reported cases with acute haematogenous osteomyelitis in the iliosacral joint.

[Surgical treatment of intra-articular calcaneus fractures]. / Zur operativen Behandlung von intraartikulären Kalkaneusfrakturen.

The instable fractures of os calcis are usually treated by conservative methods with early functional mobilization. In a few cases we think that in the Tongue Type and especially in the Joint Depression Type of Essex-Lopresti a surgical treatment may be useful to reestablish the congruence and the geometry of the joint surface.