Additional Value of FDG-PET/MRI Complementary to Sentinel Lymphonodectomy for Minimal Invasive Lymph Node Staging in Patients with Endometrial Cancer: A Prospective Study

BACKGROUND

Lymph node metastases (LNM) are rare in early-stage endometrial cancer, but a diagnostic systematic lymphadenectomy (LNE) is often performed to achieve reliable N-staging. Therefore, this prospective study aimed to evaluate the benefit of [18F]-Fluorodeoxyglucose (FDG) PET/MRI complementary to SPECT/CT guided sentinel lymphonodectomy (SLNE) for a less invasive N-staging Methods: 79 patients underwent a whole-body FDG-PET/MRI, SLN mapping with 99mTc-Nanocolloid SPECT/CT and indocyanine green (ICG) fluoroscopy followed by LNE which served as ground truth.

RESULTS

FDG-PET/MRI was highly specific in N-staging (97.2%) but revealed limited sensitivity (66.7%) due to missed micrometastases. In contrast, bilateral SLN mapping failed more often in patients with macrometastases. The combination of SLN mapping and FDG-PET/MRI increased the sensitivity from 66.7% to 77.8%. Additional SLN labeling with dye (ICG) revealed a complete SLN mapping in 80% (8/10) of patients with failed or incomplete SLN detection in SPECT/CT, reducing the need for diagnostic systematic LNE up to 87%. FDG-PET/MRI detected para-aortic LNM in three out of four cases and a liver metastasis.

CONCLUSIONS

The combination of FDG-PET/MRI and SLNE can reduce the need for diagnostic systematic LNE by up to 87%. PET/MRI complements the SLN technique particularly in the detection of para-aortic LNM and occasional distant metastases.

Dual-Time-Point Posttherapy 177Lu-PSMA-617 SPECT/CT Describes the Uptake Kinetics of mCRPC Lesions and Prognosticates Patients' Outcome

177Lu-PSMA-617 is an effective therapeutic option in metastasized castration-resistant prostate cancer (mCRPC). However, some patients progress under treatment. We hypothesized that the tracer kinetics within the metastases may influence the therapy effectiveness and tested this hypothesis by analyzing uptake parameters on 2 consecutive posttherapy SPECT/CT scans. Methods: mCRPC patients treated with 177Lu-PSMA-617 and with available posttherapy SPECT/CT imaging (24 and 48 h after the first treatment) were enrolled retrospectively. Volumes of interest were defined on lymph node metastasis (LNM) and bone metastasis (BM) on both SPECT/CT scans. The reduction of the percentage injected dose (%IDred) between the 2 SPECT/CT scans was computed. We compared %IDred of responders (prostate-specific antigen drop ≥ 50% after 2 cycles of 177Lu-PSMA-617) and nonresponders. We tested the association of %IDred with progression-free survival and overall survival (OS) using a univariate Kaplan-Meier (KM) analysis and a multivariate Cox regression model. Results: Fifty-five patients (median age, 73 y; range, 54-87 y) were included. %IDred in LNM and BM was greater in nonresponders than in responders (for LNM, 36% in nonresponders [interquartile range (IQR), 26%-47%] vs. 24% in responders [IQR, 12%-33%] [P = 0.003]; for BM, 35% in nonresponders [IQR, 27%-52%] vs. 18% in responders [IQR, 15%-29%] [P = 0.002]). For progression-free survival, in KM analysis, greater %IDred in LNM (P = 0.008) and BM (P = 0.001) was associated with shorter survival, whereas in multivariate analysis, only %IDred in LNM was retained (P = 0.03). In univariate KM analysis of OS, greater %IDred in BM was associated with shorter survival (P = 0.002). In multivariate OS analysis, BM %IDred (P = 0.009) was retained. Conclusion: The 177Lu-PSMA-617 clearance rate from mCRPC metastases appears to be a relevant prognosticator of response and survival, with faster clearing possibly signaling a shorter radiopharmaceutical residence time and absorbed dose. Dual-time-point analysis appears to be a feasible and readily available approach to estimate the likelihood of response and patients' survival.

Non-invasive estimation of split renal function from routine 68Ga-SSR-PET/CT scans

Objective

Patients with impaired kidney function are at elevated risk for nephrotoxicity and hematotoxicity from peptide receptor radionuclide therapy (PPRT) for advanced neuroendocrine tumors. Somatostatin receptor (SSR)-PET/CT imaging is the method of choice to identify sufficient SSR expression as a prerequisite for PRRT. Therefore, our study aimed to explore whether split renal function could be evaluated using imaging data from routine SSR-PET/CT prior to PRRT.

Methods

In total, 25 consecutive patients who underwent SSR-PET/CT (Siemens Biograph mCT^®) before PRRT between June 2019 and December 2020 were enrolled in this retrospective study. PET acquisition in the caudocranial direction started at 20 ± 0.5 min after an i.v. injection of 173 ± 20 MBq [⁶⁸Ga]Ga-ha DOTATATE, and the kidneys were scanned at 32 ± 0.5 min p.i. The renal parenchyma was segmented semi-automatically using an SUV-based isocontour (SUV between 5 and 15). Multiple parameters including SUVmean of renal parenchyma and blood pool, as well as parenchyma volume, were extracted, and accumulation index (ACI: renal parenchyma volume/SUVmean) and total kidney accumulation (TKA: SUVmean x renal parenchyma volume) were calculated. All data were correlated with the reference standard tubular extraction rate (TER-MAG) from [^99mTc]Tc-MAG3 scintigraphy and glomerular filtration rate (GFR_{CDK - EPI}).

Results

SUVmean of the parenchymal tracer retention showed a negative correlation with TER_MAG (r: -0.519, p < 0.001) and GFR_{CDK - EPI} (r: -0.555, p < 0.001) at 32 min p.i. The herein-introduced ACI revealed a significant correlation (p < 0.05) with the total tubular function (r: 0.482), glomerular renal function (r: 0.461), split renal function (r: 0.916), and absolute single-sided renal function (r: 0.549). The mean difference between the split renal function determined by renal scintigraphy and ACI was 1.8 ± 4.2 % points.

Conclusion

This pilot study indicates that static [⁶⁸Ga]Ga-ha DOTATATE PET-scans at 32 min p.i. may be used to estimate both split renal function and absolute renal function using the herein proposed "Accumulation Index" (ACI).

Diagnostic Performance of Dynamic Whole-Body Patlak [18F]FDG-PET/CT in Patients with Indeterminate Lung Lesions and Lymph Nodes

BACKGROUND

Static [¹⁸F]FDG-PET/CT is the imaging method of choice for the evaluation of indeterminate lung lesions and NSCLC staging; however, histological confirmation of PET-positive lesions is needed in most cases due to its limited specificity. Therefore, we aimed to evaluate the diagnostic performance of additional dynamic whole-body PET.

METHODS

A total of 34 consecutive patients with indeterminate pulmonary lesions were enrolled in this prospective trial. All patients underwent static (60 min p.i.) and dynamic (0-60 min p.i.) whole-body [¹⁸F]FDG-PET/CT (300 MBq) using the multi-bed-multi-timepoint technique (Siemens mCT FlowMotion). Histology and follow-up served as ground truth. Kinetic modeling factors were calculated using a two-compartment linear Patlak model (FDG influx rate constant = Ki, metabolic rate = MR-FDG, distribution volume = DV-FDG) and compared to SUV using ROC analysis.

RESULTS

MR-FDG_mean provided the best discriminatory power between benign and malignant lung lesions with an AUC of 0.887. The AUC of DV-FDG_mean (0.818) and SUV_mean (0.827) was non-significantly lower. For LNM, the AUCs for MR-FDG_mean (0.987) and SUV_mean (0.993) were comparable. Moreover, the DV-FDG_mean in liver metastases was three times higher than in bone or lung metastases.

CONCLUSIONS

Metabolic rate quantification was shown to be a reliable method to detect malignant lung tumors, LNM, and distant metastases at least as accurately as the established SUV or dual-time-point PET scans.

Whole-Body Magnetic Resonance Imaging (MRI) for Staging Melanoma Patients in Direct Comparison to Computed Tomography (CT): Results from a Prospective Positron Emission Tomography (PET)/CT and PET/MRI Study

PURPOSE

The consideration of radiation exposure is becoming more important in metastatic melanoma due to improved prognoses. The aim of this prospective study was to investigate the diagnostic performance of whole-body (WB) magnetic resonance imaging (MRI) in comparison to computed tomography (CT) with ¹⁸F-FDG positron emission tomography (PET)/CT and ¹⁸F-PET/MRI together with a follow-up as the reference standard.

METHODS

Between April 2014 and April 2018, a total of 57 patients (25 females, mean age of 64 ± 12 years) underwent WB-PET/CT and WB-PET/MRI on the same day. The CT and MRI scans were independently evaluated by two radiologists who were blinded to the patients' information. The reference standard was evaluated by two nuclear medicine specialists. The findings were categorized into different regions: lymph nodes/soft tissue (I), lungs (II), abdomen/pelvis (III), and bone (IV). A comparative analysis was conducted for all the documented findings. Inter-reader reliability was assessed using Bland-Altman procedures, and McNemar's test was utilized to determine the differences between the readers and the methods.

RESULTS

Out of the 57 patients, 50 were diagnosed with metastases in two or more regions, with the majority being found in region I. The accuracies of CT and MRI did not show significant differences, except in region II where CT detected more metastases compared to MRI (0.90 vs. 0.68, p = 0.008). On the other hand, MRI had a higher detection rate in region IV compared to CT (0.89 vs. 0.61, p > 0.05). The level of agreement between the readers varied depending on the number of metastases and the specific region, with the highest agreement observed in region III and the lowest observed in region I.

CONCLUSIONS

In patients with advanced melanoma, WB-MRI has the potential to serve as an alternative to CT with comparable diagnostic accuracy and confidence across most regions. The observed limited sensitivity for the detection of pulmonary lesions might be improved through dedicated lung imaging sequences.

Multiparametric Dual-Time-Point [18F]FDG PET/MRI for Lymph Node Staging in Patients with Untreated FIGO I/II Cervical Carcinoma

[¹⁸F]FDG PET/MRI was shown to have limited sensitivity for N-staging in FIGO I/II cervical carcinoma. Therefore, this prospective study aimed to investigate the additional value of multiparametric dual-time-point PET/MRI and to assess potential influencing factors for lymph node metastasis (LNM) detection. A total of 63 patients underwent whole-body dual-time-point [¹⁸F]FDG PET/MRI 60 + 90 min p.i., and 251 LN were evaluated visually, quantified multiparametrically, and correlated with histology. Grading of the primary tumor (G2/G3) had a significant impact on visual detection (sens: 8.3%/31%). The best single parameter for LNM detection was SUVavg, however, with a significant loss of discriminatory power in G2 vs. G3 tumors (AUC: 0.673/0.901). The independent predictors SUVavg, ∆SUVpeak, LN sphericity, ADC, and histologic grade were included in the logistic-regression-based malignancy score (MS) for multiparametric analysis. Application of MS enhanced AUCs, especially in G2 tumors (AUC: G2:0.769; G3:0.877) and improved the accuracy for single LNM from 34.5% to 55.5% compared with the best univariate parameter SUVavg. Compared with visual analysis, the use of the malignancy score increased the overall sensitivity from 31.0% to 79.3% (Youden optimum) with a moderate decrease in specificity from 98.3% to 75.6%. These findings indicate that multiparametric evaluation of dual-time-point PET/MRI has the potential to improve accuracy compared with visual interpretation and enables sufficient N-staging also in G2 cervical carcinoma.

Lymph Node Staging with a Combined Protocol of 18F-FDG PET/MRI and Sentinel Node SPECT/CT: A Prospective Study in Patients with FIGO I/II Cervical Carcinoma

Lymph node metastasis (LNM) is present in a minority of patients with early stages of cervical carcinomas. As conventional imaging including PET/CT has shown limited sensitivity, systematic lymphadenectomies are often conducted for staging purposes. Therefore, the aim of this prospective study was to analyze the impact of ¹⁸F-FDG PET/MRI in addition to sentinel lymph node (SLN) biopsy on lymph node (LN) status. Methods: Forty-two women with an initial diagnosis of Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) IA-IIB cervical carcinoma were included between March 2016 and April 2019. Each patient underwent preoperative whole-body ¹⁸F-FDG PET/MRI and SLN imaging with SPECT/CT after intracervical injection of ^99mTc-labeled nanocolloid. Systematic lymphadenectomy and SLN biopsy served as the reference standard. Staging using PET/MRI was performed by nuclear medicine and radiology experts working in consensus. Results: One patient was excluded from surgical staging because of liver metastases newly diagnosed on PET/MRI. The overall prevalence of LNM in the remaining 41 patients was 29.3% (12/41). Five of 12 patients with LNM had solely small metastases with a maximum diameter of 5 mm. The consensus interpretation showed PET/MRI to have a specificity of 100% (29/29; 95% CI, 88.3%-100%) for LNM staging but a low sensitivity, 33.3% (4/12; 95% CI, 12.8%-60.9%). LN size was the most important factor for the detectability of metastases, since only LNMs larger than 5 mm could be identified by PET/MRI (sensitivity, 57.1% for >5 mm and 0% for ≤5 mm). Paraaortic LNM was evaluated accurately in 3 of the 4 patients with paraaortic LN metastasis. SLNs were detectable by SPECT/CT in 82.9% of the patients or 69.0% of the hemipelves. In cases with an undetectable SLN on SPECT/CT, the malignancy rate was considerably higher (31.2% vs. 19.3%). The combination of PET/MRI and SLN SPECT/CT improved the detection of pelvic LNM from 33.3% to 75%. Conclusion: ¹⁸F-FDG PET/MRI is a highly specific N-staging method and improves LNM detection. Because of the limited sensitivity in frequently occurring small LNMs, PET/MRI should be combined with SLN mapping. The proposed combined protocol helps to decide whether extensive surgical staging is necessary in patients with FIGO I/II cervical cancer.

Correlation of C-arm CT acquired parenchymal blood volume (PBV) with 99mTc-macroaggregated albumin (MAA) SPECT/CT for radioembolization work-up

OBJECTIVE

SPECT/CT with 99mTc-macroaggregated albumin (MAA) is generally used for diagnostic work-up prior to transarterial radioembolization (TARE) to exclude shunts and to provide additional information for treatment stratification and dose calculation. C-arm CT is used for determination of lobular vascular supply and assessment of parenchymal blood volume (PBV). Aim of this study was to correlate MAA-uptake and PBV-maps in hepatocellular carcinoma (HCC) and hepatic metastases of the colorectal carcinoma (CRC).

MATERIALS AND METHODS

34 patients underwent a PBV C-arm CT immediately followed by 99mTc-MAA injection and a SPECT/CT acquisition after 1 h uptake. MAA-uptake and PBV-maps were visually assessed and semi-quantitatively analyzed (MAA-tumor/liver-parenchyma = MAA-TBR or PBV in ml/100ml). In case of a poor match, tumors were additionally correlated with post-TARE 90Y-Bremsstrahlung-SPECT/CT as a reference.

RESULTS

102 HCC or CRC metastases were analyzed. HCC presented with significantly higher MAA-TBR (7.6 vs. 3.9, p<0.05) compared to CRC. Tumors showed strong intra- and inter-individual dissimilarities between TBR and PBV with a weak correlations for capsular HCCs (r = 0.45, p<0.05) and no correlation for CRC. The demarcation of lesions was slightly better for both HCC and CRC in PBV-maps compared to MAA-SPECT/CT (exact match: 52%/50%; same intensity/homogeneity: 38%/39%; insufficient 10%/11%). MAA-SPECT/CT revealed a better visual correlation with post-therapeutic 90Y-Bremsstrahlung-SPECT/CT.

CONCLUSION

The acquisition of PBV can improve the detectability of small intrahepatic tumors and correlates with the MAA-Uptake in HCC. The results indicate that 99mTc-MAA-SPECT/CT remains to be the superior method for the prediction of post-therapeutic 90Y-particle distribution, especially in CRC. However, intra-procedural PBV acquisition has the potential to become an additional factor for TARE planning, in addition to improving the determination of segment and tumor blood supply, which has been demonstrated previously.

The Prognostic Value of Quantitative Bone SPECT/CT Before 223Ra Treatment in Metastatic Castration-Resistant Prostate Cancer

Radiolabeled bisphosphonates such as ^99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (^99mTc-DPD) typically show intense uptake in skeletal metastases from metastatic castration-resistant prostate cancer (mCRPC). Extensive bone involvement is regarded as a risk factor for mCRPC patients treated with ²²³Ra-dichloride (²²³Ra). The aim of this study was to quantify ^99mTc-DPD uptake by means of SPECT/CT before ²²³Ra and compare the results with the feasibility of treatment and overall survival (OS). Methods: Sixty consecutive mCRPC patients were prospectively included in this study. SPECT/CT of the central skeleton covering the skull to the mid-femoral level was performed before the first cycle of ²²³Ra. The bone compartment was defined by means of low-dose CT. Emission data were corrected for scatter, attenuation, and decay supplemented by resolution recovery using dedicated software. The Kaplan-Meier estimator, U test, and Cox regression analysis were used for statistics. Results: Total ^99mTc-DPD uptake of the central skeleton varied between 11% and 56% of injected dose (%ID) or between 1.8 and 10.5 %ID/1,000 mL of bone volume (%ID/L). SUV_mean ranged from 1.9 to 7.4, whereas the SUV_max range was 18-248. Patients unable to complete ²²³Ra treatment because of progression and/or cytopenia (n = 23) showed significantly higher uptake (31.9 vs. 25.4 %ID and 6.0 vs. 4.7 %ID/L; P < 0.02). OS after ²²³Ra (median, 15.2 mo) was reduced to 7.3 mo in cases of skeletal uptake that was 26 %ID or higher, as compared with 30.8 mo if lower than 26 %ID (P = 0.008). Similar results were obtained for %ID/L and SUV_mean SUV_max did not correlate with survival. %ID/L was identified as an independent prognostic factor for OS (hazard ratio, 1.381 per unit), along with number of previous treatment lines. Conclusion: Quantitative SPECT/CT of bone scans performed at baseline is prognostic for survival in mCRPC patients treated with ²²³Ra.

Transitioning to whole-body SPECT/CT in prostate cancer staging: a new concept for a better imaging workflow

AIM

 Whole-body bone scan (BS) is the clinical standard in detecting bone metastases in prostate cancer patients. Additional SPECT/CT has allowed to significantly increase its diagnostic accuracy. However, performing both planar and additional SPECT/CT prolongs the total examination time and lowers patient throughput. In this study we aim to assess the diagnostic performance of a SPECT/CT-only protocol compared to the traditional procedure that is BS with a facultative SPECT/CT in case of unclear findings.

METHODS

 50 patients with high-risk prostate cancer and suspected bone metastases were enrolled in this retrospective study. All patients received a whole-body Tc-99m-DPD BS followed by a 3 field-of-view (FOV) SPECT/CT (GE Discovery 670 Pro^®) covering an area from the vertex to the mid-femur. Metastatic lesions were evaluated visually on BS and SPECT/CT and correlated to PSA-levels.

RESULTS

 Detection rate was up to 50 % higher in SPECT/CT than in BS (n = 2829 vs. n = 1942; p < 0.001), but 31/1942 (1.5 %) lesions detected on BS were located out of the SPECT/CT field-of-view. In our analysis a PSA-level of > 80 µg/l could be defined as a cut-off-value for metastatic spread beyond mid-thigh, as no patient with PSA< 80 µg/l had localizations outside the SPECT/CT field-of-view (AUCPSA = 0.95, p < 0.001 sensitivity: 100 %, specificity: 77 %, NPV: 100 %, PPV: 67 %). The SPECT/CT-only protocol did not prolong acquisition time significantly as compared to BS.

CONCLUSIONS

 In patients with high-risk prostate cancer presenting with PSA < 80 µg/l and absent clinical symptoms, vertex to mid-thighs 3-FOV-SPECT/CT was representative for the entire skeletal system and was able to detect more lesions than planar acquisition. This procedure did not prolong patient handling time significantly.

[Trochanteric femoral fractures]

At the present time proximal femoral fractures account for 30% of all fractures referred to hospitals for treatment. Our population is ageing, the proportion of patients with post-menopausal or senile osteoporosis is increasing and therefore the number of proximal femoral fractures requiring urgent treatment is growing too. In the age category of 50 years and older, the incidence of these fractures has increased exponentially. Our department serves as a trauma centre for half of Prague and part of the Central Bohemia Region with a population of 1 150 000. Prague in particular has a high number of elderly citizens. Our experience is based on extensive clinical data obtained from the Register of Proximal Femoral Fractures established in 1997. During 14 years, 4280 patients, 3112 women and 1168 men, were admitted to our department for treatment of proximal femoral fractures. All patients were followed up until healing or development of complications. In the group under study, 82% were patients older than 70 years; 72% of those requiring surgery were in their seventies and eighties. Men were significantly younger than women (p<0.001) and represented 30% of the group. The fractures were 2.3-times more frequent in women than in men. In the category under 60 years, men significantly outnumbered women (p<0.001). The patients with pertrochanteric fractures were, on the average, eight years older than the patients with intertrochanteric fractures, which is a significant difference (p<0.001). The mortality rate within a year of injury was about 30%. Trochanteric fractures accounted for 54.7% and femoral neck fractures for 45.3% of all fractures. The inter-annual increase was 5.9%, with more trochanteric than femoral neck fractures. There was a non-significant decrease in intertrochanteric (AO 31-A3) fractures. On the other hand, the number of pertrochanteric (AO 31-A1+2) fractures increased significantly (p<0.001). A total of 1 394 fractures were treated with a proximal femoral nail; a short nail was used in 1260 and a long nail in 134 of them. A dynamic hip screw (DHS) was employed to treat 947 fractures. Distinguishing between pertrochanteric (21-A1, 31-A2) and intertrochanteric (31-A3) fractures is considered an important approach because of their different behaviour at reduction. Pertrochanteric fractures occurred more frequently (81.5%); the patients' age was higher (80 years on the average) and women outnumbered men at a ratio of 3:1. Intertrochanteric fractures were found in significantly younger patients (average, 72 years), with a women-to-men ratio of 1.3:1. Stable pertrochanteric fractures (31-A1) were preferably indicated for DHS surgery. Unstable pertrochanteric (31-A2) and intertrochanteric (31- A3) fractures were treated with a nail. The patients underwent surgery on the day of injury or the next day. In the case of contraindications to an urgent intervention, surgery was performed after the patient's medical condition had stabilised. The number of complications was largely related to technical errors, such as insufficient reduction or an incorrectly inserted implant. Intertrochanteric fractures were associated with a higher occurrence of complications. No implant can compensate for errors due to surgery. Serious complications can be reduced by the correct assessment of fracture type, the use of an appropriate operative technique and early treatment of potential complications. The necessity of restoring continuity in the medial cortex of the femoral neck (Adams' arch) is the requirement that should be observed. Pseudoarthrosis or varus malalignment in a healed hip should be managed by valgus osteotomy. When the femoral head or the acetabulum is damaged, total hip arthroplasty is indicated. A prerequisite for successful surgical outcome is urgently and correctly performed osteosynthesis allowing for early rehabilitation and mobilisation of the patient.

Serum-cobalt levels with metal-on-metal bearings in the cement-free total hip arthroplasty results covering two years; prospective study

PURPOSE OF THE STUDY

Total hip arthroplasty increases the use of alternate bearings to prevent polyethylene wear as the number of younger and more active patients has drastically risen. We carried out a prospective randomized study, to assess and compare clinical results and radiological changes, serum-cobalt- and serum-aluminium-levels when metal-on-metal and ceramic-on-ceramic bearings are applicated.

MATERIAL AND METHODS

After giving informed consent 80 consecutive patients were included in this prospective randomized study. They were randomly assigned to receive either a metal-on-metal or a ceramic-on-ceramic bearing in their total hip replacement. Eligible were patients with a primary coxarthrosis or an avascular necrosis of the head of femur. Of the 80 patients 54 were females and 26 males. 42 patients were randomized to a metal-on-metal bearing and 38 patients were randomized to a ceramic-on-ceramic bearing. The average patient-age was 65,8 years and the mean body mass index was 27,7 at the time of operation. Surgery was performed through a transgluteal approach in supine position under general or spinal anaesthesia. A forged conical threaded acetabular component made of titanium-aluminium-niobium alloy was used in all patients. The metal inlays and the 28 mm metal heads were made of Co-28Cr-6Mo alloy with a carbon content of 0,2%. The ceramic inlays and the 28 mm ceramic heads are Al2O3 implants. We used as femoral component a conical rectangular stem of a titanium-aluminium-niobium alloy. Cup and stem werde implanted cementfree. Clinical data werde obtained at a follow up at a minimum of two years after implantation. Patients were assessed with the Harris Hip Score and the University of California at Los Angeles activity scale. 72 of the 80 patients could be explored clinically and radiologically.

RESULTS

The 2 year follow up check showed clinically and radiologically no difference between the two groups. The median Harris HipScore was above 90 points and the UCLA score was about 7 points. The medium serum-cobalt level was in the metal-on-metal group about 1.2μg/L and in the ceramic-on-ceramic group below the detection limit. The medium serum aluminium level showed values of 1.2 respectively 1.3 μg/L. The luminescencies in the metal-on-metal group were increased, but all components of the prosthesis could be regarded as stable.

DISCUSSION

It was the goal of our prospective study to compare clinical and radiological results of hip arthroplasty in metal-on-metal and ceramic-on-ceramic bearings and assess the serum-cobalt and the serum-aluminium levels. The socalled "biocorrosion" is still a high risk element for loosening of implants because of aseptic osteolysis. A higher release of polyethylene and metal particles is triggered, which leads to a slow but continuous process of inflammation. Apart from the debris also metal ions in a higher concentration are released, so that we could detect after some years in patients with artificial implants a higher level of metal in blood and urine. So far we did not recognize any carcinogenity or the appearance of renal disorders, or other mutagene effects in our patients. We could also not observe any fractures in ceramic implants. We are convinced that short time and intermediate reports are necessary, although final judgement can only be based on long term data.

CONCLUSION

Our prospective randomized study showed after two years no difference clinically between the two groups of metal-on-metal and ceramic-on-ceramic bearings with total endoprostheses of the hip. Although medium serum-cobalt level in the metal-on-metal group with 1,2u/L is a significant higher value, whereas it lies in the ceramic-on-ceramic group below the detectable limit.

Results covering 20 years use of the cement-free Zweymüller Alloclassic total endoprosthesis of the hip joint

PURPOSE OF THE STUDY

From an initial group of 206 hips in 190 patients we carried out a retrospective clinical and radiological control of 74 hips in 72 patients covering a period of 20 years.

MATERIAL AND METHOD

Indications in 74 operated hips evidenced 48x(64.9%) primary and 26x(35.1%) secondary coxarthrosis. The average age at the time of operation was 53 years (37 years-68 years). All 72 patients with 74 hips received cement-free self- cutting Alloclassic screw cups of pure Titanium together with a cement-free square Alloclassic stem consisting of Titan- Aluminium-Niob alloy according to Zweymüller. Regarding the technique of operation we used the approach after Watson-Jones in the supine position. As prophylaxis against thrombosis 40% of the patients received derivates of heparine and 60% had anticoagulant therapy with cumarine. Prophylaxis against heterotopic ossifications were not carried out at this juncture in our department.

RESULTS

After an average post-operational examination lapse of 20 years we were able to examine 72 patients (37.9%) with 74 hips (35.9%) clinically and radiologically. Further classification of the 72 patients records 47 females and 25 males. The average age at the time of operation was 53 years and at the time of post-operational check-up to 74 years. For the clinical post-operational check-up (n=74) we used the Harris Hip Score. Further evaluation shows 12x(16.2%) excellent results, 26x(35.1%) good and 29x(39.2%) fair results. In 7 patients (9.5%) we had to observe poor results because of multimorbidity, although also in these cases stability of TEP had been achieved. The radiological post-operational check-up of the 74 stable hips (35.9%) shows an average excentric position of the head of 1.4 mm (0 mm up until 4 mm) compared with 1 mm after 10 years. Over an average of about 20 years we carried out an exchange of the inlay and the head because of excentric position of the head, which correlates to a rate of reoperation of 6.8%.

DISCUSSION

In 2000 and 2001 we published our 10 year results with cement-free Alloclassic screw cup and cement-free stem in 133 hips in 123 patients and compared our findings with those of other authors. After 10 years we saw only 3 % complications with cups and an overall re-operation rate of 6.7%. The 20-year-results show in all cases stable components of both cups and stems. 5 patients (6.8%) had to undergo re-operation with an exchange of inlay and head, whereby the components of the prosthesis themselves turned out to be stable. An average polyethylene abrasion of 1 mm after 10 years compares with a value of abrasion of 1,4 mm after 20 years. The 6.8% rate of re-operation after 20 years indicates the excellent results of the use of cement-free Alloclassic total endoprosthesis system of the hip according to Zweymüller.

CONCLUSIONS

The biocompatible qualities of modern prosthesis material lead to a quicker and optimal bony incorporation of the pros- thesis components. The excellent 20-year-results show a broad indicative spectrum, component stability of the prosthesis in all patients and therefore encourage the further use of cement-free hip implants in the future.

[Periprosthetic fractures of the hip]

PURPOSE OF THE STUDY

It is the aim of our study to present the results of our way of treatment of the periprosthetic fractures, with the cemented as well as the cement-free stems.

MATERIAL

From 1.1.1988 until 31.3.2005 we operated 42 periprosthetic fractures of the hip in 41 patients. 31 of our patients were females, 10 of them males. In 22 cases we operated the right side, 18 times the left side and once we had to operate both sides, but at different times. We used the Vancouver classification scale for the grading of the fractures. In our study we excluded type A fractures; we registered 41 type B fractures and one only type C fracture. The reason for periprosthetic fracture in all these 42 cases was definitely a trauma. In 6 cases we found pre-existing loosening of the stem. We have grouped our patients under two headings: 1. Primary cemented stems (n=13) 2. Primary cement-free stems (n=29) The average age at the time of primary operation was 63.6 years in the group of cemented stems and 67.2 years with the cement-free implants.

METHODS

The principle of this operation lies in a stable technique of osteosynthesis. If one operates on a stable stem one uses a one and only technique of osteosynthesis. Patients who also suffer from a loosening of the stem, are treated by replacement of the stem combined with a particular form of osteosynthesis. We generally use a transgluteal access with an L-shaped detachment of the Musc. vastus lateralis. In the group of cemented stems (n=13) we carried out a replacement of the stem 6 times and in the group of cement-free stems (n=29) we had to replace the implant on 7 occasions. Analysing the osteosynthesis technique we find the use of titanium cerclages and titanium elements on 35 occasions, in both groups taken together. As implant for the stem we preferred the modulated revision stem according to Zweymüller. Clinical post-operational examination of our patients was carried out according to the Merle d'Aubigne score and two x-rays at different levels.

RESULTS

After an average post-operational check-up time of 3 years and 2 months, we were able to examine 8 patients with cemented stems (61.5%), 4 of whom had replacement of the stem by a cement-free implant. In the cement-free group we evaluated 24 patients after an average time of 4 years and 11 months. In this group we had 5x a replacement of the stem, 3x of these we could operate cement-free. The post-operational radiological check showed an excellent building-up of bone structure without any dislocation of the implant in all 32 cases.

DISCUSSION

The average age of our patients shows 77 years with those with cemented stems and 74.5 years in the ones with cementfree implants. Analysis of the cemented stems shows a loosening rate of more than 50%, which coincides with the findings of many other authors. After a couple of years using cups of polyethylene we were confronted with the problem of the so-called Polyethylene disease. These alterations may finally lead to a loss of bone quality, to mechanical loosening of the implant and an increase in danger of fracture. When we discuss the group of patients with cement-free stems and compare them to those with cemented ones, we find a number of quite different characteristics. B2 fractures appear in a quite higher number of patients with cemented and loosened stems. In this regard, our own study is congruent with the studies of other authors. In the cement-free group we had 75% B1 fractures with a stable stem. The explanation for these figures is, that the cement-free implants were well incorporated in the bone structure.

CONCLUSIONS

The choice of operative procedure when treating periprosthetic hip fractures depends on the type of fracture and the stability of the prosthesis. Our own very positive experiences and the then emerging results lead to a certain strategy in procedure. That means, for us, the use of a cement-free modulated revision stem according to Zweymüller combined with a particular technique of osteosynthesis, using titanium cerclages and titanium elements.

Initial experience using the inverse prosthesis of the shoulder

PURPOSE OF THE STUDY

The aim of our retrospective study is to show that in cases of very serious degenerative alteration of the shoulder as well as massive Cuff arthropathy, there is a valid reason for the indication of an inverse prosthesis of the total shoulder joint. We therefore describe operation technique as well as evaluation of our own results, including complications.

MATERIAL

From October 2000 to October 2005, 24 patients had 25 Delta prostheses implanted. All these 25 implantations were carried out by the author personally, using the Delta prosthesis, in Hybrid technique.

METHOD

In all 25 implantations we used a lateral access by splitting the Deltoideus. We implanted the Glenoid component cement free, and we cemented the prosthesis of the Humerus in all our cases. After an average post-operational examination time of 3 years and 9 month, we examined clinically and radiologically, 23 patients (92%) with 24 implants. Pain, mobility and activity in every-day life were considered in the clinical post-operative check up.

RESULTS

Evaluation of pain showed that 14 patients (60,9 %) were free from pain and 9 patients (39,1 %) showed a great improvement in their medical state. In all cases we could clearly see that as far as mobility and activity in every-day life were concerned, a significant improvement hat occurred. The post-operative rate of complications showed the figure of 2 luxations (8 %). The luxation of the first patient could be repositioned in a non-operative way. The second patient was reoperated twice and we exchanged the shaft of the Humerus. In no instance did we discover any obstacle to the healing of wounds or any infections.

DISCUSSION

When the indication is carefully handled the inverse prosthesis of the shoulder is an excellent way of treatment of serious degenerative alteration of the shoulder joint and major Cuff arthropathy. The operation, which is technically demanding, should only be carried out by an operator experienced in shoulder operations. The rate of luxations can certainly be lowered with the accumulation of experience and strict adherence to the precise way in technique called for by this operation.

CONCLUSION

With elderly patients the inverse shoulder prosthesis is a good alternative way of treatment of serious degenerative alteration of the shoulder and massive Cuff arthropathy.

Serum aluminium and cobalt levels after ceramic-on-ceramic and metal-on-metal total hip replacement

In a randomised study, 28 patients with a mean age of 62.2 years (32 to 81) with osteoarthritis or avascular necrosis of the hip received either a ceramic-on-ceramic or a metal-on-metal total hip replacement. Apart from the liners the acetabular and femoral components were made of Ti-Al-Nb alloy. The serum aluminium and cobalt levels were measured before, and at one year after surgery. The 15 patients in the ceramic-on-ceramic group had a median pre-operative aluminium level of 1.3 microg/l (0.25 to 8.4) and a cobalt level below the detection limit. At one year the aluminium level was 1.1 microg/l (0.25 to 2.3) and the cobalt level was 0.4 microg/l (0.15 to 0.7). The 13 patients in the metal-on-metal group had a median pre-operative aluminium level of 1.9 microg/l (0.25 to 4.4) and a cobalt level below the detection limit. At one year the median aluminium level was 0.9 microg/l (0.25 to 3.9) whereas the cobalt level was 1.4 microg/l (0.5 to 10.5). This increase in the cobalt level at one year was significant (p < 0.001). Our findings indicate that ceramic-on-ceramic bearings do not cause elevated levels of serum aluminium in the first post-operative year.

[Medial opening-wedge high tibial valgus osteotomy, using a stable TomoFix plate, in genu varum arthritis: surgical technique]

The authors present the technique of high tibial correction osteotomy by the medial opening procedure, with the use of an angle-stable TomoFix plate. The prerequisite for a long-term good outcome of corrective osteotomy in genu varum is to achieve limb alignment permitting transfer of weight-bearing from the affected medial compartment to the healthy lateral compartment of the knee. The development of implants that maintain a stable angle has facilitated corrective osteotomy with an opening wedge on the medial side of the proximal tibia. These implants provide stable fixation even when a high correction of the mechanical axis is needed. The authors present the case of a patient with varus malalignment following a fracture of the tibia. In order to achieve correction of the limb's mechanical axis, it was necessary to open the proximal tibia osteotomy with a wedge that was 2.5 cm on the outer side.

[Long-term results with Zweymuller cement-free Alloclassic stem]

AIM OF STUDY

The aim of our study is to show the long-term results using the Zweymüller cementless Alloclassic stem.

METHOD

In our retrospective study 133 from 206 cases (64.4%) were examined after 10.6 years. The examination was done clinically (Scheme after Merie d'Aubigné) and radiologically. The average age was 72 years (48-92 years) at the time of examination.

RESULTS

Intraoperative complications occurred in 3 cases (1.5%), 2 were temporary sciatic-nerve paresis and 1 was a stem fissure. Nine cases had been revised (6.7%). In four of these cases the inlay and the head had to be changed, in two cases mechanical loosening of the cup was found; furthermore, there were one removal of heterotopical ossification and one early infection. Stem problems appeared in only one case with deep infection and had been revised twice. There was neither stem sinking nor mechanical loosening in our series. The average polyethylene wear using a ceramic head with 32 mm diameter was 1 mm after 10.6 years. Clinically excellent results were found in 90% of the cases.

CONCLUSION

The long-term results using the cementless Zweymüller stem with a rectangular transversal section and easy operation technique over 20 years are excellent Because of the cortical anchorage and the biocompatible titanium alloy the Zweymüller stem can be used in all femur forms and in different age groups.

[Ten years experience with the cementless alloclassic cup according to zweymüller.]

Because our department of orthopaedic surgery deals with the cementless hip replacement for more than 15 years, we have performed a retrospective study and a critical analysis of our patients. In the time between 01. 05. 1987 and 31. 12. 1989 we implanted 206 primary cement-free total endoprostheses of the hip in 190 patients. After an average time taken for postoperative check-ups of ten years and seven months we evaluated 133 hips (64,6 %) in 123 patients (64,7 %) clinically and radiologically. The clinical postoperative check-up according to the score of Merle d'Aubigne demonstrated very good and good results in 90 % of our cases. After 10,6 years the radiological measurement showed an average polyethylene wear of 1 mm. The critical analysis of our patients amounted to 3 % of cup complications.The therapy with the reoperations of 9 patients (6,7 %) will also be discussed. In the discussion we are concerned with the results and problems of other authors, who are engaged with the cementless hip replacement. Summarizing we can declare, that the cementless Alloclassic cup to Zweymüller has a lot of advantages: ideal primary stability simple surgical technic optimal bony incorporation low polyethylene wear For the future we recommend a change of the headsize from 32 mm to 28 mm. In young and active patients we propose a metal-metal or a ceramic-ceramic pairing. Key words: cementless cup, primary stability, low polyethylene wear, 28 mm headsize.

[Limited indication for percutaneous lumbal nucleotomies.]

The aim of our retrospective study is to show how very circumspect we are to use this method. The clinical symptoms of our patients were lumbalgia or lumboischialgia with or without neurological deficiencies. All these patients were resistent to conservative therapies. We accepted for operation only patients who suffered from protrusions and types of prolaps without perforation of the posterior longitudinal ligament. 179 operations on the vertebral discs were performed in our department between 01. 01. 1992 until 31.12.1997. Of this number 165 (92 %) were conservative nucleotomies (63 females and 102 males) and 14 patients (8 %) hat percutane nucleotomies and discos-copies (6 females and 8 males). The average age at the time of operation was 49 years (from 12 to 81 years) with patients who had an open operation, whilst the patients who had percutane nucleotomy had an average age of 42 years (26 to 56 years). The time span between postoperative checkups was on average about 40 months (3 years and 4 months). The shortest postoperative checkup period was 2 months and the longest 71 months (5 years and 11 months). Of the 14 cases mentioned we operated 9 patients in the segment L4/5, 4 patients in the segment L5/S1 and one patient in the segment L3/4. In 7 instances it was the right side that was injured and 7 times it was the left side which was injured. We performed all operations under general anaesthesia, the patient lying prone on the abdomen with lumbal lordosis raised as much as possible. We always used an X-ray picture enlarger on two planes. As far as subjective pain is concerned, an analysis of the findings gives the following results: 100 % improvement 6 patients, 80 % improvement 2 patients, 50 % improvement 3 patients, no improvement 3 patients. Five praeoperative existing motorial deficiencies had completely vanished postoperatively. As to eventual complications, we had one patient suffering from a lesion at the root of L4 on the right side with postoperative Spondylodiscitis L3/4 who was treated in a conservative way. When patient selection for this method is critically considered, the advantage of endoscopic operation lies in minimal invasion and rapid rehabilitation is associated with it.

[Retrospective study on femoral neck lengthening osteotomy]

Our retrospect study refers to the problem of improved flexibility of the hip joint, elongation of the leg as well as decrease of pain. Patients suffering from Coxa vara, a high positioned Trochanter and a short neck of the femur underwent triple osteotomy with a distal transposition of the Trochanter major. All 8 patients had a thorough clinical (according to the scheme by Merlé de Aubigné) and radiological postoperative checkup. The results were analyzed and showed an average increase of the length in leg of 1.9 cm and and average increase of capacity of abduction of 11 degrees. From these findings we draw the conclusion that triple osteotomy operation should be performed only on patients whose hip joints are free from arthrosis or show only insignificant symptoms of arthrosis.

[Plastic operation of the cruciate ligament (part I).]

In the submitted paper the authors describe in the introduction various possible ways of using autologous, homologous and heterologous transplants. A graft taken from the patellar ligament with two bone blocks from the patella and head of the tibia is, because of the great structural strength, the transplant of choice. As far as the surgical technique is concerned, the authors abondoned the open method because of its known disadvantages such as major arthrotomy and associated damage of proprioceptors of the knee joint. The authors are using the semi-open arthroscopic method, whereby artroscopic methods are definitely preferred. Positive aspects of arthroscopic methods are definitely preferred. Positive aspects of arthoscopy such as inspection of the joint, treatment of associated injuries, sparing of Hoffa's body and atraumatic surgical technique all are an advantage for the patient. An obvious advance in the surgical technique is the fixation of bone blocks by interference screws. This leads to early functional treatment using Lennox-Hill's orthesis and full burdening after 3-4 weeks. As most recent animal experiments confirmed that incorporation of the transplant from the lig. patellae is not completed before 12-14 month, it is no advantage to allow the patients to relieve the weight on the extremity. Shortening of the period of treatment reduces also trophic disorders on the operated extremity. Key words: instability of the knee joint, anterior cruciate ligament, plastic operation.

[Reconstruction Osteotomy by Morscher's Method in Coxa Vara.]

Between January 1, 1989 and December 31, 1994 the authors performed in eight patients prolongation osteotomy of the neck of the femur with transposition of the greater trochanter. The patients comprised six women and two men, in four instances the left and four instances the right side was operated. The indications comprised in four patients congenital dysplasia of the hip joint with a shorter externity, is three patients Perthes disease, incl. in one patient postluxation m. Perthes, in one patient a state following fracture of the cervix. By Morscher's osteotomy prolongation of the extremity can be achieved and improved biomechanics of the hip joint. The method is recommended especialy younger patients with mild arthritic changes.

[Plastic Operations of the Anterior Cruciate Ligament (Part II).]

Between January 1, 1988 and December 31, 1993 125 operations of the anterior cruciate ligament were performed in 27 women and 98 men. 58 operations were on the left side, 67 on the right side. In the case - history an injury during leisure time was recorded in 84.8% of the patients, during sports activities in 94%. Of 125 patients 122 were examined by arthroscopy, three were operated by the semiopen approach. The mean age at the time of surgery was 29 years. The selection of the time of surgery indicates that 98% of the patients were operated as early secondary operations and as secondary operations (after 4 weeks). Of 125 patients 122 (97.6%) were examined repeatedly after a mean interval of 43 months. For evaluation the authors used a modification of the "Lysholmscore". According to the latter in 95% very good results were achieved. For evaluation of the stability the authors used a strict test, i.e. the Lachman test and KT-1000 measurements. As to severe complications, they recorded one deep infection, as to late complications there were two cases of arthrofibrosis with "cyclops syndrome". Key words: anterior cruciate ligament, ligamentoplasty.

[Initial experience with arthroscopy of the joint of the hand.]

In the submitted paper the authors give an account on the development of arthroscopy of the joint of the hand and comments on arthroscopic anatomy and technique of the procedures. In the authors' hospital the procedure is carried out under general anaesthesia, the patient lies on his back with the arm suspended in extension by the fingers, using a 3-5 kg weight. The authors use a needle arthroscope of Storz Co. with a diameter of 2.7 mm which is inserted into the joint from a dorsomedial approach. During the period between Jan. 1, 1990 and Dec. 31, 1993 14 arthroscopies of the joint of the hand were made in 10 women and 4 men, three times on the left and 11 times on the right hand. The mean age of the patients was 25 years and the mean follow-up period 2 years (8 months - 3 years). Revealed surgical findings: - chondromalacia 7 times; - damage of the disk twice; - rupture of the disk and chondromalacia 3 times; - synovitis once; - no pathological intraarticular finding once (cysta lunata without perforation). By surgery with irrigation and arthroscopic procedures such as resection of a ruptured disk and elimination of a defect of the authors were able to achieve improvement in mor than 70% of the patients.

[Experience with dynamic hip screw in retrochanteric and subtrochanteric fractures of upper femur.]

From 1st January 1988 to 31st December 1994, 105 patients were given 106 dynamic hip-screws in the Orthopaedic Department of the Public General Hospital, Zwettl. The average age at the time of operation was 77.6 years and the time lapse between the accident occuring and the operation performed was on average 31 hours. In 94.3% of the cases we could perform a closed reduction and in 88.7% we used a 135 degree-DHS. The four-hole plate dominated in 73.6% of the plates used. Internal complications totalled 23.6% out of which 9.5% of the patients died during their hospitalization. Here one must take note that the patients who died were of advanced age and multimorbid. We carried out clinical and radiological postoperative examinations on 54 patients (51.4%) with 55 operations (51.9%). The postoperative examinations took place on an average of 33 months (2 years and 9 months). The clinical postoperative examinations were carried out according to the Merle D'Aubigne system - 29 excellent, 58 good and 13 poor. The radiological postoperative examinations disclosed an ossian consolidation of 100% for 54 patients with 55 operations. Taking into account the classification of fractures according to the AO we find that the DHS is mainly used to treat fractures A 1/1-, A 1/2- and A 2/2-. With the exception of subtrochanteric fractures in which we have lately been using the Gamma-Nail, we have the DHS as a technically relatively simple and inexpensive implant in the treatment of pertrochanteric fractures of the neck of the femur.

[Endoscopic subacromial decompression.]

In 23 patients with problems in the region of the shoulder caused by subacromial pathology endoscopic subacromial decompression was performed. The group comprised 11 men and 12 women aged 30 to 72 years. The patients were evaluated according to the UCLA score. The mean follow-up period was 23.3 months. After critical evaluation 14 excellent, 8 satisfactory and one average result were achieved. Endoscopic subacromial decompression, as describe, is an effective and safe technique in treatment of the impingement syndrome. Rapid restoration of the function is made possible by the low postoperative morbidity and fact that the deltoid muscle is not damaged. Key words: impingement syndrome of the shoulder, arthroscopy of the shoulder.

[Arthroscopic Surgical Technique and its Short-term Results in the Treatment of Relapsing Anterior Dislocation of the Shoulder.]

In the submitted paper the autors describe the arthroscopic technique of treatment of relapsing anterior and combined low-anterior dislocation of the shoulder. The principle is a three-layer reconstruction tehchnique of the anterior portion of the joint. It involves reinsertion of the ruptured complex labrum-ligaments, three glenohumoral ligaments and the tendon of the m. subscapularis on the anterior surface of the cervix of the scapula blood stained in advance. Across the listed structures 4-6 U-shaped stitches which are pulled through a canal bored in the cervix of the scapula on the dorsal side and these stitches are fastened by knots over the fascia of the m. infraspinatus. Another modification of this technique is knotting of dorsally drawn fibres across an absorbable foil on the dorsal surface of the neck of the scapula. For after-treatment for four weeks a ready made shoulder dressing of LINK Co. is applied. In the submitted paper the authors give an account of the early results obtained in 11 operated patients who were treated by this technique of ventral arthroscopic capsulorraphy. The follow-up period was 16-33 months (average 24 months). Key words: dislocation of the shoulder, operating technique, arthroscopy.

[Initial experience with percutaneous lumbar nucleotomy and discoscopy.]

Ever since percutaneous lumbar nucleotomy and discoscopy were introduced great hopes in this method were raised by specialists and patients. Based on the initial euphoric comments in the professional press, the authors started to use this procedure in 1992. During the period between Jan. 1 1992 and Dec. 31 1993 at the orthopaedic department of the General Hospital in Zwettel 69 operations of the disc were performed. The number comprised 62 conventional nucleotomies and 7 percutaneous nuc-leotomies combined with discoscopy. The mean follow-up period in patients with percutaneous nucleotomy and discocopy was 14 months (3-24). With regard to preoperative and postoperative development the therapeutic results were evaluated as follows. The authors proved strictly limited indications of this new surgical method and its inclusion in the therapeutic plan in protrusion and prolapse of the disc. As revealed by analysis, this method can be used to extend the hitherto valid therapeutic spectrum, if strictly limited indications are used. Key words: percutaneous nucleotomy, discoscopy.

[Initial Experience with a New Generation of Zweymüller's Endoprosthesis.]

In the first part of our paper innovations as regards the non-cemented endoprosthesis of the hip joint by Zweymüller's method are described. As a special advantage the double cone of the socket is mentioned which as to its anatomical shape is close to the acetabulum and makes only slight resection of the bone on the floor of the acetabulum possible. At the Orthopaedic Department of the hospital in Zwettl between 1984 and 1987 more than 100 polyethylene Endler screw sockets were implanted. From the end of 1987 to the beginning of 1993 the authors used non-cemented endoprostheses as designed by Zweymuller. Based on the mentioned advantage of the new biconical socket, as suggested by Zweymuller, the authors implant this generation since the beginning of 1993. During the period from Jan.1, 1993 to Dec. 31, 1993 68 endoprostheses of the hip joint of the new type were used during primary operations. The follow-up of patients respected clinical and radiological criteria (pattern of Merle d'Aubigne). Of 68 patients 67 (98.5%) were followed up. In the present retrospective study in particular heterotopic ossifications were investigated, whereby the years 1992 and 1993 were compared. Key words: non-cemented total endoprosthesis of the hip joint, non-cemented biconical socket.

[Arthroscopic treatment of lateral dislocation of the patella.]

Between Jan. 1, 1988 and Dec. 31, 1993 at the Orthopaedic Department of the hospital in Zwettl 12 patients with lateral dislocation of the patella were operated arthroscopically. In two habitual, in 10 relapsing and in one a new dislocation of the patella was involved. The patients were followed up clinically and radiologically, the mean follow-up period being 47 months. Every patient was subjected to complete arthroscopic examination of the knee joint. In the final stage of diagnostic arthroscopy an optical instrument was introduced from a medial retropatellar approach and lateral release was carried out. Subsequently from a 1.5 cm skin incision in the area of the medial facet of the patella a needle with a loop from the instrumentarium for sutures of the meniscus was inserted and from a medial parapatellar approach at both ends a PDS fibre, grade 0, was pulled out and by this thus developed U-shaped stitch medial capsulorrhaphy was achieved. In this way a total of 5-7 stitches were made. Extension of the U-stitches revealed on arthroscopy a satisfactory medialization of the patella. Further treatment involved application of a plaster tube in extension for 4 weeks: The authors discuss in the submitted paper the surgical technique and clinical and radiological results. Key words: dislocation of the patella, arthroscopy, lateral release.

[Preradiologic stage of idiopathic femur head necrosis demonstrated by intraosseous pressure measurement]

Early identification is the focal point of efforts aimed toward efficient diagnosis and treatment of osteonecrosis. With the intraosseous pressure measurement method of Ficat and Arlet it is possible to determine the onset of this disease at the preradiological stage. At the Vienna-Speising Orthopedic Clinic 11 out of a total of 66 cases of idiopathic necroses of the femoral head were diagnosed at the preradiological stage. The only treatment given in these cases was decompression by removal of a bone cylinder. The follow-up examination after an average of 22 months revealed very good results in all cases, both subjectively and roentgenologically (stage deterioration did not occur in a single case).

[Bilateral subcutaneous rupture of the tendon of the anterior tibial muscle and its differential diagnosis]

An own singular case of a subcutaneous rupture of the tibialis anterior tendon on both sides is added to the few one-sided which have been published. A connection between a damage of the tendinous tissue and a minimal injury be discussed. The problem of diagnosis is described in this case. In the differential diagnosis the tibialis-anterior-syndrome, a pain in the peritenon or insertion are compared. Early suture of the torn tendon with appropriate post-operative treatment is the treatment of choice.

Assembly of nonneural microtubules in the absence of glycerol and microtubule-associated proteins

Microtubule protein from Ehrlich ascites tumor cells purified by an in vitro polymerization process in the absence of glycerol and calcium chelators contains several accessory proteins but lacks the high molecular weight proteins which are present in neurotubulin. DEAE-Sephadex chromatography of two-times cycled tubulin removes these nontubulin proteins, resulting in pure tubulin, as critically examined by sodium dodecyl sulfate gel electrophoresis. This tubulin can readily assemble into microtubules in assembly buffer, at low magnesium concentrations, without glycerol and at tubulin concentrations above 0.8 mg/mL. Electron microscopy shows that the tubules are identical with normal microtubules. When the purified tubulin fraction was reduced and carboxymethylated, a significant minor protein component could be observed electrophoretically, migrating between alpha- and beta-tubulin. At present, the identity and function of this protein are not known. The results demonstrate that the in vitro assembly of tubulin from Ehrlich ascites tumor cells does not require high molecular weight proteins or gamma-like factor(s) as has been proposed for the neurotubulin system.