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Osseous metastases to the hand are very rare. Only a single case of osseous metastasis of hepatocellular carcinoma to the hand has been reported in the literature to date. We report a case of osteolytic metastasis of the right first metacarpal as first manifestation of unresectable, alpha-fetoprotein-negative hepatocellular carcinoma (pT3, Nx, M1, UICC stage IVB, Okuda's stage I). The therapy consisted of R0-resection and hormonal therapy with tamoxifen 2 x 10 mg/d orally. Generally patients with metastatic cancer to the bones of the hand have a very poor prognosis.

65 knee arthroplasties in 60 patients (5 x both sided, 49 x female, 11 x male) with a Genesis Total Knee System (54 x cemented, 6 x cementless, 4 x tibial cemented/femoral cementless, 1 x tibial cementless/femoral cemented) were evaluated according to the Knee Society Score and the HSS Score with a medium follow up of 4 years und 5 months (3 years and 4 months to 5 years and 11 months). In 48 patients the diagnosis was gonarthrosis, in 17 patients it was rheumatoid arthritis. The medium postoperative Knee Score was 80.9 points, the Function Score was 73.7 points. The HSS Score obtained 80.9 points. 87.7% of the patients were excellent or good. The Genesis Total Knee arthroplasty has proved to be reliable for osteoarthritis and rheumatoid arthritis in medium term.

A novel model for the investigation of the microcirculation in synovial tissue of the mouse knee joint is presented. The mouse knee joint was exposed on a specially designed plexiglass stage with a slight flexion. After partial resection of the skin, the patella tendon was cut transversally, which allowed for visualization of the "Hoffa's fatty body", an intraarticular fatty tissue containing synovial cells on the interior surface of the joint. An intravital fluorescence microscope was adjusted to observe the microcirculation of this intraarticular synovial tissue without opening of the joint capsula. For staining of the plasma, fluorescein isothiocyanate (FITC)-dextran was used, and for the staining of leukocytes rhodamine 6G was used. The tissue investigated presents with a high-density honeycomb-like capillary network, containing some postcapillary venules and a few arterioles. The following parameters were assessed off-line using a computer-assisted microcirculation analysis system: flow and diameter of arterioles and postcapillary venules, as well as functional capillary density. Moreover, leukocyte-endothelial cell interaction was quantified by counting the number of rolling cells and cells adhering to the endothelium in postcapillary venules. As an indication of endothelial leakage, macromolecular extravasation was also assessed. To validate the model, we investigated these parameters at three time points during an observation period of 60 min. There was no change in functional capillary density, nor in vessel diameter after 60 min of observation. Moreover, there was neither a change in the number of rolling cells, nor in the number of cells adhering to the endothelium nor in extravasation of FITC-dextran, thus indicating the stability of the preparation. The new model allows the quantitative analysis of the intraarticular microcirculation of the synovial fatty tissue in vivo. It provides insight into the dynamics of synovial microcirculation and leukocyte-endothelial cell interaction in acute or chronic joint inflammation.

Surgical resection of osseous metastases is becoming more and more important in obtaining longer overall survival in carcinoma patients. In 228 cases surgically treated at our institution between 1980 and 1993, the survival was 49% after 1 year, 32% after 2 years, 22% after 3 years and, finally, 11% after 5 years. Retrospectively evaluated, breast and thyroid carcinoma proved to be of positive prognostic influence and lung cancer of negative significance. As a main significant parameter, further extraosseous metastases were evaluated. The prognostic influence of the number of osseous lesions could only be demonstrated in breast and renal cell carcinoma without involvement of further organs. Age and location of the skeletal lesions proved to be of no prognostic influence. Based on these prognostic parameters, three subgroups of patients with worse, median and good long-term survival could be defined. In conclusion, the indication and amount of surgery can be based on these prognostic factors, leading to a decrease in morbidity and hospitalization time in patients with limited survival.

This study was undertaken to determine whether there is a correlation between magnetic resonance imaging (MRI) and clinical success after reconstruction of the anterior cruciate ligament (ACL). In a prospective study, 28 patients underwent clinical and MRI examination 3 to 5 years after ACL reconstruction with either the semitendinosus tendon (n = 15) or patellar ligament (n = 13). Knee stability was assessed both clinically and by KT-1000 arthrometer testing. Magnetic resonance imaging was performed with a 0.2-T dedicated system (Artoscan, Esaote, Italy) including sagittal and oblique coronal T1 and T2-weighted images. Magnetic resonance images were evaluated by two readers with regard to signal intensity and continuity of the ACL reconstruction and presence or absence of posterior cruciate ligament buckling. Knee stability and MRI evaluation were each summarized in a 6-point score. Statistical correlation was checked with the Spearman ranked correlation for testing non-normal distributed samples. Statistical testing of all patients' results together showed a significant correlation with a prediction value of 12%, indicating no significant correlation between clinical results and MRI evaluation. Separate statistical testing of the patellar ligament and semitendinosus patients' results showed no significant correlation in either group at all. Thus, no correlation between clinical stability and MRI could be established. Magnetic resonance images after ACL reconstruction using the techniques mentioned above should be interpreted with caution, as they may not relate to the clinical function of the ligament.

Between 1989 and 1995, 326 hip arthroplasties were surgically revised in our clinic because of loosening. For evaluation of loosening, we used history, clinical examination, radiographs, bone scans and arthrography with digital subtraction technique. In 130 cases (40%), surgery was planned by plain radiographs. In 116 cases (89%) a correct diagnosis of loosened components was made. Of the 72 patients (22%) with an additional bone scan, 87% (63 patients) had a correct diagnosis. Fifty-four patients (17%) with different findings were examined by hip arthrography; in 83% (45 patients) the diagnosis was confirmed intraoperatively. In 93% (65 patients) of 70 patients (21%) with bone scans and arthrography, surgery confirmed the diagnosis. Sensitivity for loosening of the socket was 61% by bone scan and 85% by digital subtraction arthrography; specificity was 75% in each case. Sensitivity for loosening of the stem was 71% by bone scan and 65% by digital subtraction arthrography; specificity was 80% and 88%, respectively. Our results showed that in most cases of suspected loosening of total hip arthroplasties, analysis of plain radiograph series can lead to an accurate diagnosis in 85%-90%. In cases of uncertainty, we suggest the additional use of digital subtraction arthrography, which has a similarly high diagnostic quality. Because of the low sensitivity of nuclide bone scanning (about 60%) and its dependence on prosthetic material and fixation, we do not recommend primary scintigraphy. It can be helpful in problematic cases with additional questions like activity of ectopic bone formation.

Nitric oxide production by the inducible NO-synthase in the synovium and chondrocytes is known to be enhanced during chronic joint inflammation and aseptic loosening of joint prostheses. Due to the distinct side effects of non-selective NO-inhibitors on the macro- and microhemodynamics, we investigated the in vivo changes after selective (N-iminoethyl-L-lysine (NIL)) versus non-selective NO-synthase inhibition (NG-nitro-L-arginine methyl ester (L-NAME)) in the synovium of the mouse knee joint. Our results show a significant decrease in the functional capillary density and an increase in the leukocyte accumulation after L-NAME injection. In contrast, NIL did not alter the microhemodynamics or the leukocyte-endothelial cell interaction in the synovium, indicating its potential use for therapeutic selective inhibition of iNOS in joint inflammation.

The purpose of the study was to determine the changes that might be detected using magnetic resonance imaging (MRI) on patients with chronic lateral epicondylitis of the elbow and to judge its value concerning the clinical treatment. Thirty-four patients with chronic lateral epicondylitis were included in a prospective study. All individuals underwent MRI of the elbow on a 0.2-T dedicated system. The MRI findings were interpreted by an independent radiologist without knowledge of the clinical findings. In 6 surgical cases an additional histological study was done. The biopsy of the extensor tendon was performed for correlation with the MRI. In 21 of 34 symptomatic patients, increased signal changes in T1- and T2-weighted images were seen. In a further 11 cases, the morphology and signal intensity were normal. The histopathological analysis of 6 surgical cases confirmed the preoperative MRI findings by showing either focal fibrous degenerative tendon tissue or microruptures of collagenous fibres. MRI in patients with chronic lateral epicondylitis can help to differentiate the disease and may be of use in clinical management, preoperative planning, and in the evaluation of the degree of degeneration at the common extensor tendon insertion.

Persistent pain after knee arthroplasty is often caused by aseptic loosening, implant failure, unphysiological alignment (especially of the patella), infection, scars and neuroma. In a case of a 70-year-old patient pain and swelling after knee arthroplasty persisted despite three revision procedures. Surprisingly, a non-Hodgkin's lymphoma was found in femoral bone marrow histology. A metastatic non-Hodgkin's lymphoma as cause of pain and swelling after knee arthroplasty, like in this case, is rare and has not been described up to now.

Goal of Surgery: Restoration of normal knee function., Indications: Acute avulsion of the anterior cruciate ligament (ACL) from its femoral origin., Contraindications: Mid substance and remote tears., Positioning and Anaesthesia: Supine. Knee flexed, hip bent to 30 degrees . General or regional anaesthesia., Surgical Technique: Step 1: Arthroscopy to confirm site of rupture, meniscus repair if necessary. Step 2: Mobilisation of semitendinosus tendon, left attached distally. Step 3: Mini-arthrotomy, securing of ACL stump with atraumatic suture. Step 4: Transfer of ST-tendon through 5 mm drill holes through tibial head and lateral femoral condyle. Step 5: Fixation of tendon and ACL-sutures with staple at the exit of the femoral drill hole., Postoperative Management: Knee orthosis for 6 weeks, CPM, physiotherapy. ROM day 0-2: 0-10-10 degrees ; day 3-11: 0-0-60 degrees , day 12-42: 0-0-90 degrees . Increase of weight bearing 10 kg/week from operation date. Bicycling and running permitted 3 months post-op. Full sport activity after muscle power has reached that of opposite side. LMW heparin until full weight bearing., Possible Complications: Thrombosis. Embolism. Infection. Failure of reconstruction. Osteoarthritis., Results: During 1 year, 116 patients were operated. Follow-up after 42 to 57 months (average 52 months) included 95 patients (82%). Of these, 76 underwent full examination (average age 33 1/2 years, 20-49 years), 11 answered a questionnaire, 8 had suffered re-injury. Average Lysholm score was 92 points (+/-13). Tegner activity scale amounted to 7.2 points pre-injury, 7.1 points at follow-up. Anterior translation (KT 1000 arthrometer testing at 89 N) was identical to opposite side in 25 patients, less than 2 mm in 14, up to 4 mm in 19, up to 6 mm in 15, more that 6 mm in 3 patients. Pivot shift was negative or trace 73 times, and positive in 3 patients. ROM was full in 54 patients, 17 times the flexion was limited up to 10 degrees . Ten times extension lag was less than 5 degrees , and twice between 5 and 10 degrees .

A simulator test was carried out in the hip joint simulator on a metal-on-metal coupling of a modified CoCrMo alloy. The test was run up to 1.9 million cycles and the tribological behaviour of the coupling was documented by means of roundness measurements and scanning electron microscopy. It is seen that the tribological system metal on metal is characterized by mixed friction in the artificial hip joint, thus generating material contacts that are documented by the roundness variation and by the SEM contact zone analysis, showing "three-body" wear of this system. The roundness variations indicate that running-in wear is to be noticed at first with a decreasing tendency over the 1.9 million cycles. Nevertheless, this observation does not allow any prognosis as to the wear rates in the case of a higher number of cycles. It must be taken into consideration that aqua destillata had to be used as a lubricant for technical reasons; the use of serum/Ringer solution might have produced different results. Further investigations in the hip joint simulator and on revised metal-on-metal couplings will be carried out in this respect.

The creep and wear behaviour of Chirulen, Hylamer and Enduron, materials which differ only in their manufacturing procedures, was examined and compared. Chirulen is manufactured by being pressed into form by plates, whereas Hylamer and Enduron are shaped by tubes. Hylamer differs from Enduron in that intermediate material processing is undertaken with the goal of improving the initial material. The wear and deformation rate was determined by means of the ring-on-disc testing device after 360,000 cycles and after 1.0 x 10(6) cycles, respectively. The static tests for the determination of wear were carried out at a contact stress of 5.62 MPa and a testing time of 100 h in analogy to the ring-on-disc tests. Chirulen and Hylamer demonstrated comparable wear with a tendency toward a lower wear rate in Hylamer, while Enduron presented a clearly higher wear rate.

In a retrospective study, 22 patients treated surgically for solitary or multiple myeloma between 1980 and 1993 were analysed. The main complaint was pain. A fracture was observed in 7 cases and motor-sensory impaired neurology due to spinal compression in 3. Apart from incisional biopsies, tumour resections, reductions (with and without stabilization by osteosynthesis) and endoprotheses were performed either at the extremities or on the spine. In addition, radiation and chemotherapy were included in the therapeutical concept. Early mobilization was achieved in all cases, and the 5-year survival rate (Kaplan-Meier method) was 48%. The results presented in this study demonstrate that a variety of surgical interventions can be of importance in the treatment of myeloma of the bone, ranging from biopsy or even curative resections in selected cases to endoprosthetic replacement. Thus, good functional results can be achieved and maintained over often long survival times.

A case of calcific tendinitis of the pectoralis major insertion with cortical bone erosion is presented. Clinical and laboratory findings showed a significant inflammatory reaction. Both CT and MR images demonstrated the extent of the lesion providing additional information on the dimensions of inflammatory soft tissue and bone marrow reaction. Biopsy was performed and histology revealed the typical features of calcification, inflammation and giant cell reaction.

Posttraumatic bone-cyst formation is a known but rare process. Typical location is the distal radius, usually as a result of a greenstick fracture. The pathogenesis is unknown; however, subperiosteal migration of fat or hemorrhage with later absorption may cause cyst formation. We present the first reported case of MR imaging of this lesion. At MRI subperiosteal hemorrhage was found to be the cause of cyst formation.

In a 52-year-old female patient and a 50-year-old patient with a malign tumor of the right distal femur (stage IIIb) respectively the left distal tibia (stage Ia according to Enneking), the extremely rare primary leiomyosarcoma of the bone was diagnosed. The mortality of the primary leiomyosarcoma of the bone is 50%, the mean survival time after diagnosis is 3.4 years. Diagnosis of a primary leiomyosarcoma of the bone is only possible after a secondary leiomyosarcoma has been excluded as well as by histopathological including immunohistochemical examination. The operative procedure is the therapy of choice. A neoadjuvant and/or adjuvant radio- or chemotherapy can be useful.

In a 50-year-old patient with a malignant tumor of the left distal tibia (stage la, according to Enneking) undermining the cartilage of the ankle joint, an extremely rare primary leiomyosarcoma of bone was diagnosed. The diagnosis of a primary leiomyosarcoma of bone is possible only after a secondary (metastatic) leiomyosarcoma has been excluded. Furthermore, typical histopathological features, including immunohistochemical staining results, are required for the diagnosis. Surgery is the therapy of choice. An R0 resection should always be attempted.

The aim of this follow-up study was to see if, by the application of a special endoprosthesis for the replacement of the proximal femur, a radical tumour resection could be achieved and/or the function of the lower limb could be preserved or restored respectively. Between 11/1986 and 12/1992 a proximal femoral endoprosthesis was implanted in 9 patients with metastases in the proximal femur. In 21 cases this special endoprosthesis was used in the revision of conventional cemented total hip arthroplasties with loosening of the implant and extreme bone loss at the proximal femur. Twenty-three patients were seen for a follow-up examination with an average follow-up period of 20 months. In all cases the walking ability was preserved or restored respectively. The majority (22/23) of the patients had complete or, nearly complete pain relief. In those patients with skeletal metastases, were no cases of local reoccurrence. The majority problem of this endoprosthesis was the increased risk of dislocation. There is a clear indication for such a special endoprosthesis in the treatment of primary and secondary bone tumours in the proximal femur. For revision of cemented total hip prostheses with loosening and bony defects a revision prosthesis with uncemented distal fixation should be used.

One of the factors determining the wear of UHMWPE used as acetabular cup material is the lubricating properties of the head materials. In order to determine the lubricating properties, the wettability of Al2O3, ZrO2, CoCrMo and N-coated TiAl6V4 was established. Wettability is determined by the surface energy of the head material (solid-state material), which was measured via the contact angle of drops of fluid. As head material, appropriate rings from the Ring-on-Disc Test as per International Standard 6474 were used. The poorest wettability was associated with CoCrMo. The wettability of Al2O3 and ZrO2 was comparable. Worthy of note is the tendentially good wettability of N-coated TiAl6V4.

Shoulder pain may be due to various reasons. It is primarily produced by changes in the periarticular structures of the shoulder joint. The term "periarthritis humeroscapularis" (PHS), often used at diagnosis, is unsuitable however because it prevents differentiation of the various clinical pictures related to the anatomical structures. Among the anatomical structures concerned, above all the rotator cuff and here especially the suprasinatus muscle must be mentioned. Also the long biceps tendon and the shoulder joint capsule are, according to Welfling, locations of painful processes, not to forget the subacromial bursa. The pathology responsible for the clinical symptoms and signs is primarily produced by degenerative changes. They lead to tendopathy, as well as to tendon rupture, and also seem to be of importance in connection with calcifying tendopathy. Capsule shrinkage in shoulder stiffness can also be influenced by neighboring degenerative processes. This also applies to isolated bursitis. Today thorough clinical and radiological clarification makes a differentiated diagnosis possible so that the vague term "periarthritis humeroscapularis" can be dropped.

The extreme stress on the long head of the biceps tendon is defined by its specific anatomic course, with its proximity to the rotator cuff, the intertubercular groove and the acromion. We studied the morphologic and cross-sectional anatomy of the long head of the biceps tendon in 104 cadavers to analyze degenerative lesions. Degenerative changes in the tendon (disorganized collagen fibers and large mucoid deposits) occurred mainly in the distal bicipital groove and near the origin of the tendon from the superior part of the glenoid labrum. The results of histologic examination identified sites that possibly have a predilection for tendon rupture.

The Thermoelastic Stress Analysis (THESA) is a widely used procedure in motorcar- and airplane engineering. This study investigated the reliability of THESA for stress analysis of human bone. A human femur was cyclic stressed and the resulting stress pattern was scanned from the surface of the bone by means of the thermoelastic stress measuring instrument SPATE 9000. To proof whether the scan of SPATE 9000 is equivalent to the stress distribution of human femur surface, strain gauges are used to control the results at two different regions of the femur diaphysis under equal but static conditions. It could be shown, that both measuring methods lead to corresponding results of stress pattern on human femur surface.

The creep and wear behaviour of pressed UHMWPE and extruded UHMWPE was compared, taking Chirulen and extruded UHMWPE of the Lennite type as examples. Using the ring-on-disc test, the wear and deformation volumes per 360,000 cycles were determined. The static tests were performed at surface pressures of 5.62 MPa and 9.37 MPa, while the test duration was 41.86 and 100 hours, respectively. The surface pressures result from the axial forces of 900 N and 1500 N, respectively, and a ring surface analogous to the DIN 58,835 and ISO 6474 standards. Between conventionally pressed and the extruded UHMWPE material differences of up to 350% in the sums of wear and deformation were found. It was noted that already at low surface pressures the extruded UHMWPE is more susceptible to creep deformation than is the conventionally pressed material, and that this effect dramatically increases at high surface pressures.

During surgery of limbs tourniquet up to a maximum of 2 h is frequently applied which may cause ischemia/reperfusion injury (IRI). During this condition the presence of vasomotion may have consequences for the perfusion and nutritive state of the tissues. We used a noninvasive plethysmographic method to investigate periodic changes in limb circumference (volumotion) in healthy male patients (n = 24) undergoing surgery for knee injury. To facilitate surgery a tourniquet was applied to the thigh, which caused an IRI of the leg. Results are given as mean of all values +/- SEM. Immediately after tourniquet release (duration 57.75 +/- 5.19 min) blood lactate levels in the femoral vein increased significantly from 1.40 +/- 0.08 to 2.59 +/- 0.20 mmol/l (p < 0.001) and pH fell from 7.39 +/- 0.01 to 7.32 +/- 0.01 (p < 0.001). Preoperatively 10 out of 24 patients (42%) showed signs of volumotion on the injured leg with a periodicity ranging from 0.8 to 6.9 cycles/min, whereas none showed volumotion in the control leg (p < 0.001). In the second measurement, taken after surgery and reperfusion while peripheral sympathetic nerves were blocked, 7 out of 18 patients (39%) showed volumotion on the injured leg and 0 on the control leg (p < 0.004). 6 h after IRI, volumotion was observed in 11 out of 17 patients (65%) on the injured leg and in 1 patient (6%) on the control leg (p < 0.001). The mean volume change in the patients with volumotion on the injured leg was 0.057 +/- 0.007 ml/100 ml tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

For the visualization of joint structures, magnetic resonance imaging (MRI) has definite advantages over other imaging modalities. High soft tissue contrast and multiplanar capabilities contribute to adequate representation of the joints. With surface and special coils as well as high gradient field strengths, superior spatial resolution can be achieved, thus allowing for depiction of fine anatomical details. Newly developed pulse sequences, especially with fat suppression techniques and utilization of paramagnetic contrast agents (gadolinium complexes) have improved image contrast. Examination techniques, results and diagnostic value of MRI in various joints are discussed. Close cooperation between orthopaedic surgeons and radiologists is mandatory for effective and economically acceptable use of MRI in the diagnosis of joint disorders.

A retrospective study was performed to evaluate the outcome of operative treatment of posterior cruciate ligament (PCL) lesions in 115 patients operated on between 1980 and 1989. Follow-up was possible in 89 patients at 18-124 months postoperatively (average 76 months). In 65 re-examination was possible, while 24 patients returned a questionnaire. The results of patients who were operated on in the acute state were superior to those with chronic instabilities (Lysholm 79.9 +/- 18.5 vs 64.3 +/- 22.1; Tegner 5.7 +/- 2.3 vs 4.2 +/- 2.2; instrumented posterior drawer 5.3 +/- 3.5 mm vs 5.9 +/- 3.8 mm). On the other hand, the preoperative scores of symptomatic patients with chronic instabilities (Lysholm 38.8 +/- 22.0; Tegner 2.1 +/- 1.7) were clearly lower. Extraarticular procedures (Hughston) slightly improved symptoms in posterolateral instabilities. Olecranization of the patella had no influence on the results. Interpretation of the data is difficult as there was no matched group of patients with nonoperative treatment. A reviews of the literature suggests that isolated PCL tears are best treated with conservative management. Only in cases where associated ligamentous injuries require operative treatment should PCL reconstruction be performed. Chronic posterior instabilities should be treated operatively only if the patients are severely symptomatic. However, complete restoration of knee stability was usually not achieved with the techniques presented in this paper.

Several ways for HIV inactivation in bone allografts are being discussed. These methods must be efficient, but they must not compromise biologic properties of the allografts. According to animal studies, moderate heat treatment of bone allografts in a 65 degrees C waterbath has no adverse effects on osseointegration. A clinical follow-up study of 49 patients with heat treated bone allografts was conducted. 37 patients with conventional cryopreserved allografts were included in the study as controls. Average follow-up time was 27 months. Results were evaluated by clinical and X-ray examination, using a modified radiologic score. No significant differences in the two groups were detected, except for a slight retardation in bony integration of the heat treated allografts between week 39 and 52 postoperatively. Complication rates were 11.4% vs. 10.7%. In conclusion, moderate heat treatment of bone allografts appears to be a practicable and safe method to improve safety in bone transplantation in clinical practice. In addition to the known guide lines for bone banking heat treating of allografts should be further improved in order to minimize the low remaining risk of infection which exists despite of the three months test.

Sixty-five patients were operated on for acromioclavicular dislocation between 1980 and 1991. Seventeen type II and 48 type III dislocations according to the criteria of Tossy et al. were treated. Three different surgical techniques were employed. (1) tension band wiring, (2) a modification of the Bosworth repair, (3) reconstruction of the ligaments with augmentation by a PDS (polydioxanon) cord. Forty-four patients could be investigated retrospectively, and an additional 12 were recorded by questionnaire. The Taft score was used, representing self-assessment, clinical statements and radiological findings. Of all investigated patients 87.5% had a normal range of motion without any loss of strength, and 32% suffered an osteoarthritis of the acromioclavicular joint. The average Taft score was 9.8. With respect to the three surgical techniques, reconstruction of the ligaments augmented by a PDS cord produced the best result, an average Taft score of 10.8.

Recently, the availability of bone allografts has declined dramatically, due to the three-month HIV test which is often difficult to obtain. Accordingly, there is a search for methods to inactivate HIV in bone allografts without compromising the biologic quality of the grafts. Chemical substances require long exposure and desorption times, to ensure that no toxic agents remain within the bone before actual transplantation. X-ray inactivation leads to complete loss of any osteoinductive properties of the allografts, according to some authors. In addition, the high doses that are necessary are difficult to apply. Autoclaving has been practiced in some instances, but all experimental results and some more recent clinical observations warn that osteoinductive properties of the allografts are lost during the autoclaving process. Lower temperatures (56 degrees C) are sufficient to warrant inactivation of HIV, and some experimental results and preliminary clinical observations indicate that moderate heat treatment of bone allografts in a water bath may become a useful method for virus inactivation of bone allografts.

Recently some authors have claimed that primary repair of an acute tear in the anterior cruciate ligament will fail in the long run. A review of the literature reveals that this opinion is mainly based on an American study in 1976. However, the poor results presented in this study were never reproduced. The study is critically analyzed, and 14 more papers presenting successful primary reconstructions of the anterior cruciate ligament are discussed. Preserving proprioceptive structures may be an important advantage of this technique, as it is hypothesized that the anterior cruciate ligament functions as a significant sensory organ, not only providing proprioceptive information, but also initiating protective and stabilizing muscular reflexes. In conclusion, it is recommended that primary suture be used combined with intra-articular semitendinosus tendon augmentation for rapid rehabilitation in cases of acute tears in the anterior cruciate ligament.

Within a 3-year period (1985-1988), 60 children and adolescents with knee injuries sustained mainly while skiing or playing football (soccer) underwent clinical examination, X-radiography and arthroscopy. Nearly all the patients still had open epiphyseal plates in the knee region. Arthroscopy revealed more severe intra-articular trauma than had been suspected on the basis of clinical findings. The skiing injuries most commonly involved anterior cruciate ligament tears, whereas injuries of the patellar retinaculum and medial meniscus lesions predominated in soccer injuries. On comparison with arthroscopic diagnosis, clinical diagnosis was erroneous in about 45%. The most common mistaken clinical diagnosis was "medial meniscus tear". Of the 60 knee joints subjected to arthroscopy, 40 were severely enough injured to warrant surgery. Only one had normal intra-articular findings. The study demonstrates that children and adolescents can suffer knee trauma requiring surgery, despite open growth plates. Downhill skiing and soccer are particularly risky sports in this respect. Therefore, sports injuries involving haemarthrosis are clearly an indication for arthroscopy, even in childhood and adolescence. Arthroscopy enables early identification of the type and extent of intra-articular trauma and subsequent early initiation of appropriate therapy.

The quality of cementation is of paramount importance for the long-term clinical outcome in cemented total hip replacement. Four "modes of failure" have been differentiated by various authors and correlated with the clinical findings. A finite element analysis was performed to simulate an ideally cemented femoral stem-type prosthesis as well as failure modes III (proximal anchorage of implant only) and IV (Distal anchorage of implant only). While failure mode III produces a stress distribution at the bone/acrylic cement interface, which is similar to the ideally cemented prosthesis, failure mode type IV leads to a hazardous rise of the interface stresses. This correlates well with the clinical findings given in the literature, thus validating the computer simulation used. Distal cementation only of a stem-type femoral component in total hip replacement should definitely be avoided.

In 21 human anterior cruciate ligaments removed with their synovial sheaths during autopsy and operation, nerves and nerve endings were demonstrated by light microscopy, scanning electron microscopy and transmission electron microscopy. Ultrastructural examination allowed a classification of nerve endings into three types: Ruffinian corpuscles, Pacinian corpuscles and free (afferent and efferent) nerve endings. The nerve endings corresponded to those characteristic of articular capsules. The anterior cruciate ligament shows evidence of a proprioceptive function besides its stabilizing function, which is based on its collagenous structure. Together, they probably represent the most important factor in the dynamic stabilization of the knee joint. At present it is only possible to speculate on the potential clinical significance of these findings, for example in development of rehabilitation programs and prevention strategies offering protection against anterior cruciate tears. This also applies to the question of whether to preserve the ligament during surgery for ruptures and knee-joint prostheses.

During a 9-year period we operated on 19 patients in whom the proximal tendon of the biceps brachii muscle had been disruptured. Various surgical techniques were employed, such as refixation at the processus coracoideus, tenodesis in the sulcus intertubercularis, keyhole operation, in combination with an intraarticular inspection, revision, or if necessary widening of a narrow passage ("defile"). Follow-up was possible in 15 patients for an average period of 3 years after the operation, in respect of clinical, roentgenological and isokinetic findings. Results were mainly good while employing a variety of different surgical techniques; in only 3 patients the shoulder function remained restricted, painful and/or weakened. The isokinetic maximum torque was either increased on the operated side (after coracoid refixation) or reduced (after tenodesis in the sulcus). The underlying biomechanical causes are explained. Good results can be obtained in surgical treatment of the rupture of the proximal biceps tendon provided the procedure is accurately executed while taking into consideration, at the same operation stage, the associated pathology of the rotatory cuff. For biomechanical reasons, preference should be given to the operations according to Hitchcock and Bechtol in respect of refixation, and to the keyhole operation method.

The rupture of the distal tendon of the biceps brachii is a relatively uncommon but severe injury of the upper extremity. Different techniques for surgical reattachment are described with a small number of patients. The purpose of this study was to show whether the surgical technique modified after Max Lange leads to good clinical results in the number of eleven patients who underwent physical examination between six months and eight years after surgical repair. Three patients showed a small deficit in the range of motion. Six patients had ossifications in the distal tendon, no patient had an osteoarthritis of the elbow. Strength and endurance, tested by the Cybex-II isokinetic dynamometer, showed no significant difference between operated and healthy extremity. The surgical technique modified after Max Lange is a safe and effective way for reattaching the distal tendon of the biceps brachii.

The excimer laser was thought to be an appropriate tool for the removal of bone cement without damaging the bone. However, due to its low ablation rate, its clinical use in total hip revision arthroplasty proved to be impossible. This experimental study was designed to evaluate the maximal ablation rate by adjusting the laser's parameters. Energy density, frequency, pulse duration, radiation area, quantity of pulses, and environmental conditions were varied in the experimental setup. Even with the best set of parameters the excimer laser was about ten times slower than, e.g., the carbon dioxide laser. The removal of 10 g bone cement takes about 1 h. Thus, complete cement removal by means of the excimer laser alone is not possible. However, selective application of the excimer laser in combination with other techniques could be discussed.

The use of bone allografts is often essential in orthopedic surgery. Strict donor screening, including HIV testing 3 months postoperatively, is mandatory before a transplant may be used. Yet these measures do not definitely rule out the possibility of HIV transmission, as there is a window period before infection is revealed by blood testing. Accordingly, there is a need for virus inactivation methods that can be used on bone allografts. As radiation treatment and chemical methods have a number of disadvantages, we chose a moderate heat treatment of 65 degrees C for a series of animal experiments. In 12 rabbit femoral condyles, moderate-heat-treated bone allografts were implanted into 6-mm drill holes. Twelve normal allografts and 12 empty drill holes served as controls. Radiologic and histological evaluation up to 12 weeks postoperatively revealed slow spontaneous bone remodeling from the rim to the center of the empty cavities. Normal deep frozen allografts were quickly intergrated after a short period of osteoclast reaction around the transplant, with occasional bone bridges between host and allograft. The examination of heat-treated allografts showed no differences to the controls, including morphologic aspects and the time course of osteointegration. Five zones of bone repair and osteointegration were distinguished. We conclude that thermal treatment of bone allografts has adverse effects on osteointegration in the rabbit femoral condyle. Thus, it may contribute to improving safety in human bone transplantation.

The rupture of the distal tendon of the biceps brachii is a uncommon injury of the upper extremity. For this reason, the clinical patterns are quite unknown. Between 1980 and 1989 14 patients were treated operatively because of a distal biceps tendon rupture. Aetiology, diagnostic efforts and operative treatment are demonstrated as well as the results of a follow-up of 12 patients. The results of operative treatment are quite good and point out the need for operative treatment.

The results of radiologic and clinical follow-up of 81 PCA (porous coated anatomie) hip joint prostheses implanted in our clinic between 1986 and 1988 are presented. One of the prostheses had to be explanted because of aseptic loosening after 2.5 years' implantation. Contrary to the fixation concept of the prosthesis, which requires both proximal osseointegration and free axial shifting of the distal part of the prosthesis, our follow-up radiographs showed proximal lysis of 2 mm and more as well as distal hypersclerosis of 3 mm and more in the form of endosteal bone formation in 70% of cases 3 years after implantation. On the basis of our data, the question whether these bone reactions will finally lead to aseptic loosening of the implant cannot be answered yet.

147 bone scans with 99mTc-MDP following 60 cementless hip arthroplasties were analysed at 3 to 160 weeks after operation. Results are compared to clinical evaluation according to Merle d'Aubigné. X-ray changes in a number of patients are included. In uncomplicated cases, bone scan activity decreased quickly within 26 weeks postoperatively. Decrease of scintigraphic activity was markedly delayed in patients with low Merle d'Aubigné values or persisting pain. In 4 cases, bone scan activity increased again. In these cases, reoperation revealed rotational instability of the shaft endoprostheses. Unusual x-ray phenomena such as development of a bony cup at the tip of the prosthesis or seams were found mainly in patients with less satisfying results. We consider nuclear imaging an important additional examination to evaluate bony integration of PM shaft endoprostheses after hip replacement, especially as interpretation of x-ray features alone is still doubtful.

With respect to ventral interbody fusion, rates of pseudarthrosis of up to 30% are reported. With the aim of reducing this figure, the use of dorsal fixation systems to stabilise the fused spinal units is recommended by a number of authors. The aim of these osteosynthetic procedures is to elevate the interfragmentary compression between the ventral bone block and the adjacent vertebrae. In order to measure the pressure achievable, and its local distribution, an experimental investigation involving the use of a capacitive measuring mat has been designed. The system of capacitive measurement and its application to the spine is described. The simple mode of measurement and mechanical stability, combined with high accuracy, are the specific advantages of capacitive systems of measurement. Especially in the documentation of interfragmentary pressure and pressure distribution, capacitive measuring mats are superior to comparable systems.

From 1.4. 1986 to 31.12. 1987 we operated 21 patients with a recurrent anterior dislocation of the shoulder with the Du Toit staple capsulorrhaphy. 20 patients we followed clinically and radiologically for an average period of one year and four months. By using a rating sheet 17 patients had an excellent and three patients a good result. There was, against other operation techniques, a minimally limiting of external rotation. We had no recurrents of dislocation. We concluded that the Du Toit staple capsulorrhaphy makes necessary only short postoperative immobilisation and renders an early return of motion and that a good function can be expected.

Correct treatment of destructive lesions in the vertebral column requires exact radiological evaluation with the traditional techniques of plain films, computed tomography and radionuclide scanning. With the development of magnetic resonance imaging the possibility of visualizing pathological changes of the bone marrow became apparent. To prove the value of MRJ in detecting destructive lesions of the spine 29 patients were investigated using plain radiographs, computertomographies, radionuclide scanning and MRJ. The findings were correlated to the intraoperative aspect of the lesion and the results of the histological investigation in 18 cases. MRJ showed to be a very sensitive manner of detecting bone marrow changes of different kind. Indeed characteristic changes in signal intensity were not to be observed in pathological lesions of inflammatory or tumorous genesis. So the distinction is based on morphological criterias.

Acute traumatic dislocation of the patella may be associated with osteochondral fractures. Clinical examination invariably shows a tense effusion. A detailed radiographic examination including antero-posterior, lateral and skyline views of the patella is usually necessary to establish an exact diagnosis. Once diagnosis is made open reduction and fixation of the osteochondral fracture should be carried out if it is possible. Out of 78 patients of our own with patella dislocation 24 cases suffered an osteochondral fracture. In ten cases refixation of the osteochondral fragment was achieved. Intraoperatively the alignment of the patella was controlled in any case. In cases of lateral subluxation lateral release and medial reconstruction was performed. In two cases medial transfer of the tibial tuberosity was carried out. Osteochondral fractures of the femoro-patellar groove represent an important injury in the course of acute patellar dislocation. With exact diagnosis and correct treatment congruity of the femoro-patellar joint can be restored in many cases.

Chronic inflammatory diseases, such as chronic polyarthritis or spondylarthritis ankylopoietica, can occasionally lead to vertebral instabilities of the occipitoatlantal or atlantoaxial level, requiring some form of stabilizing operation. By means of functional magnetic resonance imaging, i.e., with the cervical spine at its maximal range of flexion and extension, performed on 11 patients suffering from an instability at the above level, it was possible to demonstrate not only the extent of synovial tissue, but also how this sometimes excessive soft-tissue growth hinders an adequate reduction of the subluxated vertebrae. The importance of this investigation lies in the fact that the necessary operation can be planned appropriately. As such, three patients required a decompressing operation entailing resection of the posterior arch of the atlas, widening of the foremen magnum, or both.

For quantified evaluation of the primary stability of cementless femoral stem prostheses the operative faults: too low sized stem, distally short-lined anchoring with proximally surpassing stem and fissure or fracture of the femur shaft were simulated in autoptical test series. By inductive displacement transducers the micromotion between stem and proximal bone layer were measured in medio-lateral and ventro-dorsal direction under static load conditions before and after a dynamic loading of 50,000 cycles. The underdimensioned stem showed its instable anchoring by obviously increased micromotions in all measure plains. The proximally excelling only distally anchored prosthesis demonstrated immense amounts of motion. The fissure doesn't seem to decrease the primary stability of the stems too much. These results of the autoptical test series can only be directly transferred to the conditions of the first weeks after implantation, because the influence of later bone integration could not be considered.

Twenty-nine patients were examined by magnetic resonance imaging for various lesions of the spine. The results of these scans were compared with those of plain radiographs, computertomographs, and radionuclide bone scans. The findings were substantiated by intraoperative or histological findings in 18 cases. The MRI scans proved to be very sensitive in the detection of a wide spectrum of morphological changes of the bone marrow of vertebral bodies. Characteristic changes of the signal patterns for inflammatory and tumorous lesions were not observed. The differentiation of these lesions will presently continue to have to be based on morphological criteria.

Ruptures of the quadriceps tendon and patellar ligament are rare among injuries of the extensor mechanism of the knee when compared to fractures of the patella. 39 cases of which 31 were re-examined are being discussed with regard to therapy and results. According to our findings, ruptures of the extensor mechanism are not exclusively an injury of higher age groups. Predisposing factors for ruptures of the quadriceps tendon and patellar ligament are preexisting disease or posttraumatic sequelae. Fresh or old injuries require different operative technics. Usually, fresh ruptures can be repaired by end-to-end sutures. Old injuries require plastic procedures. Different technics are being described. Postoperatively, cast fixation is mandatory. The post-operative period of remobilisation is largely depend upon preexisting degenerative joint changes as are the post-operative results. A significant increase in post-operative osteoarthritis did not occur. Early degenerative changes in the femoro-patellar joint as seen on tangential views by the Settegast technic lead to the conclusion that the operative reconstruction does not always take into consideration the biomechanics of the femoro-patellar articulation. Immediate operative reconstruction of the ruptured extensor mechanism of the knee joint seems mandatory.