Electroencephalogram (EEG) assessment of brain activity before and after electrical stunning in the Nile crocodile (Crocodylus niloticus).

Electrical stunning is used to capture crocodiles to perform routine management procedures. It is essential from a welfare point that electrical stunning must cause unconsciousness in animals. However, there is no information of whether or not electrical stunning causes unconsciousness in the Nile crocodile (Crocodylus niloticus). The purpose of the study was to assess brain activity before and after electrical stunning in crocodiles using a 5-channel referential electroencephalogram analysis to determine consciousness. Behavioural indicators and electroencephalogram recordings of 15 captive-bred crocodiles were captured and analysed using power spectral density analysis immediately before and after stunning and then at 60 s intervals until 5 min post-stunning. A standardised stun of 170 Volts was applied for 5-7 s on the wetted neck. Unconsciousness was defined as a decrease in alpha wave power and increase in delta wave power. Three of the electroencephalograms could not be assessed. Unconsciousness was identified in 6 out of 12 crocodiles and lasted for an average for 120 s. An increase in electroencephalogram waveform amplitude and tonic-clonic seizure-like waveform activity and behaviour indicators were not reliable indicators of unconsciousness. Further research should be focused on improving the efficiency and reliability of electrical stunning.

Sources of error in acid-base analysis from a blood gas analyser result: a narrative review.

Preservation of blood pH within a narrow range is essential to optimal physiological function. This narrow pH range is maintained via the interactions of various buffer systems. Blood gas analysis is thus essential in the diagnosis and management of disorders affecting blood pH. Common methods of acid-base interpretation in veterinary science are the traditional approach, the physicochemical approach and the semiquantitative approach. However, blood gas analysis is prone to error during the preanalytical, analytical and post-analytical phases of the laboratory process. The pre-analytical phase incorporates steps in obtaining the sample, thus sources of pre-analytical error are related to operator technique. Most errors occur during the pre-analytical phase. Pre-analytical errors include entrainment of air bubbles into the sample and delays between sampling and analysis, both of which cause inaccurate measurement of oxygen and carbon dioxide tensions. The analytical phase outlines processes within the analyser. Common analytical errors are related to substances confounding analyte measurements. The post-analytical phase mainly describes interpretation of the results. Some of the approaches to acid-base interpretation require extensive post-analytical calculations, thus lending themselves to error. Errors occurring during the prior phases will be amplified. Errors in the measurement of the carbon dioxide tension (from which bicarbonate concentration and base excess are calculated) will introduce error into all three methods of acid-base interpretation. Furthermore, errors occurring in the measurements of electrolytes and lactate will result in incorrect interpretations if the physicochemical and semiquantitative approaches are applied. The potential sources of error during the various phases are reviewed.

Ketamine-medetomidine compared to tiletamine-zolazepam-medetomidine for immobilisation of semi-captive cheetahs (Acinonyx jubatus).

ABSTRACT: The immobilisation time and cardiopulmonary effects of ketamine-medetomidine (KM) and tiletamine-zolazepam-medetomidine (TZM) were compared in semi-captive cheetahs (Acinonyx jubatus). Seven healthy adult cheetahs were included in a randomised prospective crossover study. Each cheetah was immobilised on two occasions by remote injection, once with a combination of ketamine (4.93 ± 0.75 mg/kg) and medetomidine (0.038 ± 0.003 mg/kg) (KM) and once with tiletamine-zolazepam (1.16 ± 0.12 mg/kg) and medetomidine (0.039 ± 0.002 mg/kg) (TZM). Time to safe approach, characterised by absent responses to an ear flick and tail tug, was recorded as the immobilisation time. Following immobilisation, cardiopulmonary parameters were recorded, and an arterial blood gas sample analysed. Data is reported as mean ± SD and compared using a general linear mixed model (p < 0.05). Immobilisation times were no different between combinations, 11.4 ± 5.7 minutes for KM and 13.2 ± 4.6 minutes for TZM (p = 0.528). Systolic blood pressure was 218 ± 22 mmHg for KM and 210 ± 28 mmHg for TZM (p = 0.594). There was moderate hypoxaemia with both combinations with arterial oxygen partial pressure of 58.4 ± 6.6 mmHg for KM and 61.3 ± 4.2 mmHg for TZM (p = 0.368). Haematocrit was higher with KM (40.7 ± 2.5) than TZM (35.8 ± 2.8, p = 0.007). There were differences in electrolytes, with TZM resulting in higher serum potassium (4.3 ± 0.2 mmol/L, p < 0.001) and glucose (11.8 ± 2.9 mmol/L, p = 0.039) than KM. Both combinations provided acceptable immobilisation for field use, although severe hypertension was a consistent finding. Supplementation with oxygen is recommended with both combinations.

Determination of the minimum infusion rate of alfaxalone during its co-administration with midazolam in goats.

INTRODUCTION: The minimum infusion rate (MIR) of alfaxalone when co-administered with midazolam in goats was evaluated. MATERIALS AND METHODS: Eight goats (four does and four wethers) were anaesthetised, on separate occasions, with alfaxalone at an initial dose of 9.6 mg/kg/hour combined with one of three midazolam treatments: a bolus of 0.1 mg/kg followed by constant rate infusion (CRI) of 0.1 mg/kg/hour (treatment LMID), 0.3 mg/kg followed by CRI of 0.3 mg/kg/hour (MMID), 0.9 mg/kg followed by CRI of 0.9 mg/kg/hour (HMID), intravenously. Responses to stimulation (clamping on the proximal part of one digit of the hoof with Vulsellum forceps for 60 seconds) were tested every 30 minutes. In the absence or presence of a response to stimulation, the infusion rate was reduced or increased by 1.9 mg/kg/hour. Alfaxalone MIR was calculated as the mean of the infusion rates that allowed and abolished movement. Cardiopulmonary parameters were measured. RESULTS: Alfaxalone MIR was 6.7 (6.7-8.6) mg/kg/hour, 6.7 (4.8-6.7) mg/kg/hour and 2.9 (1.0-4.8) mg/kg/hour for LMID, MMID and HMID respectively. Cardiopulmonary function was minimally affected, with hypoxaemia observed two minutes into anaesthesia during all treatments. Recovery from anaesthesia was excitement-free. CONCLUSIONS: Midazolam causes a dose-dependent reduction of alfaxalone MIR in goats. Oxygen supplementation is recommended during anaesthesia with alfaxalone and midazolam in goats.

[Proximal osseous integration in THR using the cementless Vektor-Titan stem: medium- and long-term results]. / Proximale knöcherne Integration des zementfreien Vektor-Titanschafts in der Hüftendoprothetik. Mittel- und langfristige Ergebnisse.

OBJECTIVE OF THE STUDY: The objective of this study is to establish the medium-term and long-term clinical and radiological results with the cementless Vektor-Titan stem. Special consideration has been given to evaluate the extent to which the implant design achieves proximal stress transfer, thus avoiding stress shielding in the proximal femur. MATERIAL AND METHODS: From October 10, 1996, to May 18, 2000, 432 Vektor-Titan stems were implanted in 348 patients in the Wichernhaus Orthopaedic Clinic at Rummelsberg Hospital. The results were evaluated clinically and radiologically within the scope of a retrospective cohort study. The Vektor stem is a titanium straight stem designed for cementless fixation. It has a high proximal volume in the form of a three-dimensional taper with longitudinal ribs. This design achieves strong primary fixation in the proximal metaphysis. RESULTS: The survival probability of the stem was 99.08 % after a mean time of 7.5 years after surgery. One implant had to be replaced due to a traumatic periprosthetic fracture. Another had to be replaced after 9 months due to septic loosening, and a third after 14 months due to a suspected low-grade infection which, however, was not confirmed intraoperatively. The fourth stem required replacement after 75 months, again due to a periprosthetic fracture. Based on the Merle d'Aubigné score , surgery led to very good clinical results in 254 cases (58.8 %) and to good improvement in 130 cases (30.1 %). In 33 cases (7.6 %) there was a moderate improvement in the score, and in 15 cases (3.5 %) there was no improvement. Bone structure was radiologically normal in 421 cases (97.5 % of all cases). No signs of atrophy were found in the proximal femur and the trochanters. On the contrary, there was evidence of an even denser bone structure at the level of the osteotomy and the lateral implant fixation within the greater trochanter. There the trabeculae were visibly aligned towards the surface of the implant, indicative of direct biological fixation at the bone-implant interface. These findings remained unchanged over long observation periods. There were no changes along the diaphyseal stem. CONCLUSIONS: Medium-term and long-term results with the cementless Vektor-Titan stem show a low rate of implant loosening with stable metaphyseal fixation and preservation of bone structure in the proximal femur and the absence of changes along the diaphyseal stem.

Lack of nidogen-2 increases blood pressure, glomerular and tubulointerstitial damage in DOCA-salt hypertension.

BACKGROUND: Nidogen-2, an extracellular matrix protein, is ubiquitous in renal basement membranes linking the laminin and collagen IV networks. Nidogen-2-deficient (nidogen-2(-/-)) mice do not exhibit a phenotype, and renal basement membranes appear normal. The functional role of nidogen-2 in the adult kidney under pathological conditions however remains unclear. We tested the hypothesis that nidogen-2 mediated cell-matrix interactions are important to maintain glomerular integrity and structure in renal hyperperfusion and hypertension. MATERIALS AND METHODS: Two weeks after unilateral nephrectomy (UNX), desoxycorticosterone (DOCA)-salt hypertension was induced in nidogen-2(-/-) mice and their wild type littermates for 6 weeks. Renal damage was assessed by means of semiquantitative scoring, morphometric analysis, immunohistochemistry and measurement of serum creatinine and albumin excretion. RESULTS: UNX alone resulted in a very mild increase in renal damage in nidogen-2(-/-) mice compared to wild type animals. Following DOCA-salt treatment, blood pressure, serum creatinine and albumin excretion were significantly higher in nidogen-2(-/-) than in wild type mice. In addition, nidogen-2(-/-) mice showed increased mesangial cell hyperplasia and matrix expansion with higher expression of fibronectin and its receptor alpha8 integrin. Glomerular capillaries were significantly reduced in size and number. CONCLUSIONS: We demonstrate that in both mild and severe glomerular damage, lack of nidogen-2 is associated with: (i) increased mesangioproliferation; (ii) higher mesangial matrix expansion; and (iii) reduction in glomerular capillary supply. These findings suggest a critical role for nidogen-2 in the maintenance of glomerular structure in the diseased kidney.

[Allergic reaction to components of bone cement after total knee arthroplasty]. / Allergie auf Knochenzementbestandteile nach Knieendoprothesenimplantation.

There are many reports about allergic reactions in association with total hip or knee arthroplasty. While most studies focus on allergic reactions to metallic components, only few reports exist about reactions to bone cement or its ingredients. We report about a patient who developed eczema at the knee and the lower leg one year after cemented TKR. Patch testing showed as potential causes contact allergic reactions to nickel and benzoylperoxide, an ingredient of the here used bone cement. The local and temporal association between onset of eczema and knee arthroplasty suggests a causal link. Benzoylperoxide as potential contact allergen in bone cement is so far almost neglected. The development of extended testing procedures and data collection should provide further information and better care of these patients. The development of special bone cements for patients with allergic diathesis is requested.

[Melorheostosis of the foot: a case report of a rare entity]. / Melorheostose des Fusses: Falldarstellung eines seltenen Krankheitsbildes.

INTRODUCTION: Melorheostosis is a rare bony dysplasia and often recognised just sporadically by chance. CASE REPORT: We present a case of a 15 year old girl who presented a melorheostosis of the left foot. After birth there was recognized a shortening and deformity of the 2nd toe on the left foot. Furthermore she had an interphalangeal hallux valgus that displaced the 2nd toe increasingly. Thus in the last years there were more and more difficulties to wear normal shoes. Conservative therapy was not successful. We performed a lengthening extending osteotomy of the 2nd toe (a modified Weil osteotomy) and an Akin osteotomy of the interphalangeal hallux valgus. Since the surgical procedure the patient is out of any complaints. DISCUSSION: We demonstrate the radiologic and histologic findings and discuss the relevant literature and possible etiology.

[Results of operative therapy of idiopathic clubfoot using a dorsomedial approach with soft tissue preparation "à la carte"]. / Ergebnisse der operativen Behandlung des idiopathischen Klumpfusses unter Verwendung eines dorsomedialen Zuganges mit Weichteilpräparation "à la carte".

INTRODUCTION: Several concepts have been published for therapy of idiopathic clubfoot. Actually the Cincinnati approach is the "gold-standard" in operative treatment of idiopathic clubfoot. Using this approach delayed wound healing and overcorrection are wellknown complications. During the last 30 years a dorsomedial approach is used in operative treatment of idiopathic clubfoot in our clinic. Using this approach a dorsal, medial and/or lateral release can be performed. Postoperatively a plaster cast is used. The following years a rigid therapy with orthosis and support is requested. PATIENTS AND METHOD: Between June 1986 and December 2000 130 clubfoot operations with soft tissue release were performed. 119/130 (91 %) patients could be clinically and radiologically followed-up after a mean of 4.5 years (min: 2, max: 17) including 65.5 % male and 34.5 % female patients. Average age at time of operation was 7.6 months. The findings were classified according to Dimeglio. To evaluate the clinical results the score according to Laaveg and Ponseti was used. X-rays with load (a. p. and lateral view) were evaluated preoperatively and at follow-up for a. p. and lateral talocalcaneal angle, talometatarsal-I-angle, calcaneometatarsal-V-angle and the angle of the first ray. Additionally complications and recurrences were documented. RESULTS: 21.8 % of the feet were classified IV degrees , 39.5 % III degrees and 38.7 % II degrees according to Dimeglio. Recurrent clubfoot was found in 7.6 % of all cases. All angles showed a significant improve. At latest follow-up 95.6 +/- 9.2 points according to the score of Laaveg and Ponseti were achieved. Flat top talus was found in 37 cases. CONCLUSION: The dorsomedial approach allows an excellent correction of clubfeet with a low rate of complications and recurrences in comparison to other studies.

[The modified Brooker classification for evaluation of heterotopic ossifications in total hip replacement]. / Die modifizierte Brooker-Klassifikation zur Beurteilung heterotoper Ossifikationen in der Hüftendoprothetik.

INTRODUCTION: To evaluate heterotopic ossifications (HTO) in total hip replacement several classifications have been developed. Most often the classifications according to Brooker or Arcq are used. These systems enable the description of HTO on x-rays in ap view, functional aspects like range of motion are not evaluated. In several studies we could observe that patients with HTO IV degrees according to Brooker ("ankylosis") had a free or excellent range of motion. We introduce a modified Brooker classification system which enables the evaluation of HTO in two X-ray planes and allows in addition a description of hip function. PATIENTS AND METHOD: On the a.-p. X-ray view the original Brooker classification is used, on the lateral view the Brooker classification ventrally and dorsally of the longitudinal axis of the stem of the total hip replacement is used. In addition functional deficits as a sequalae of HTO are documented (1: yes; 2: no). The new classification system is used in 10 cases with HTO IV degrees according to Brooker in the a.-p .view. RESULTS: 8 cases with "ankylosis" according to Brooker showed a good range of motion. In these cases HTO I-III degrees according to Brooker were found in the lateral view. In the ap view these HTO were evaluated as HTO IV degrees because of an overlapping effect. DISCUSSION: The new classification using X-rays in two planes allows to describe HTO sufficiently especially in respect to hip function. The most important advantage of this new classification is the fact that it modifies only a widly used and accepted system. This may lead to a high acceptance of the new classification.

[Experiences with the Butler procedure for overlapping fifth toe]. / Erfahrungen mit der Weichteilkorrektur nach Butler des Digitus quintus varus superductus.

UNLABELLED: Overlapping fifth toe is a finding in pediatric orthopaedics which rarely requires operative therapy. PATIENTS AND METHOD: Between Jan. 1, 1992 and Dec. 31, 2002 five operations of an overlapping fifth toe using the Butler procedure were performed at a mean patients age of 5.5 years (min: 3, max: 9). All patients were clinically evaluated after a mean follow-up of 6 years (min: 2, max: 10) according to the score of Black. We present the technique of the Butler procedure and discuss the relevant literature. RESULTS: An excellent result was achieved in all patients. Despite the extensive soft tissue release no complications could be found. CONCLUSION: The Butler procedure is a simple and safe procedure without any need of immobilisation.

[Results and experiences of conversion of hip arthrodesis ]. / Ergebnisse und Erfahrungen der Remobilisation von Hüftarthrodesen.

INTRODUCTION: With the predictably good outcome of total hip arthroplasty today (THA), hip arthrodesis currently has limited indications. Over the long term, however, most patients develop secondary degenerative arthritis in the spine, contralateral hip, and ipsilateral knee due to overloading. The deteriorating condition of these joints eventually causes the onset of pain, which often requires conversion of a fused hip to a THA. The results and experiences of conversions of a hip arthrodesis into a THA are reported. INTRODUCTION: Between 1 January 1985 and 31 December 2001 conversion of a previously performed arthrodesis of the hip to THA was carried out in a total of 45 patients; 34 patients could be followed up after the conversion to THA after a mean of 77.5 months (min.: 24, max.: 208). The primary indications for the conversion were low back pain (n=21) and ipsilateral knee pain (n=13). RESULTS: The mean age at the time of THA was 75.3 years (min.: 32, max.: 74). The mean time interval between the arthrodesis and the conversion to THA was 30.4 years (min.: 5, max.: 66). Of 34 hips, 29 (85%) were either pain free or had minimal pain. Complications included one persisting sciatic nerve palsy, two superficial infections, two periprosthetic fractures, and two heterotopic ossifications IV degrees with one recurrence of ankylosis and one marked reduction of motion. Revision arthroplasty was performed in four hips. Postoperatively 7 patients showed no limping, 11 showed a slight limp, and 17 a pronounced limp. Recurrent dislocations occurred in one patient. CONCLUSION: We conclude that this operation can lead to satisfactory results even after a long duration of the arthrodesis. There is a high rate of complications after conversion of a hip arthrodesis to a total hip arthroplasty. These issues must be carefully considered and discussed with the patient before any conversion procedure.

[Results of fixation of osteochondral lesions of the talus using K-wires]. / Ergebnisse der Refixation der Osteochondrosis Dissecans des Talus mit Kirschnerdrähten.

INTRODUCTION: Etiology of osteochondral lesions of the talus remains uncertain, a myriad of treatment options exists. The purpose of this study is to evaluate the clinical and radiological results of fixation of osteochondral lesions of the talus using K-wires. An unstable osteochondral fragment or osteosclerotic changes in the bed of the talus were regarded as indications for the procedure. PATIENTS AND METHOD: We report a retrospective study of 20 patients who underwent fixation of osteochondritis dissecans of the talus between 1.1.1995 and 31.12.2000. There were 14 men and 6 women. The average age was 18 years (range, 11 to 52 years). The average duration of symptoms prior to surgery was 30 weeks (range, 8 to 100 weeks). RESULTS: The average duration of follow-up was 46 months (range, 18 to 93 months). The overall clinical result was rated good in 4 cases and excellent in 16 cases according to the Ogilvie-Harris score. There were no surgical complications. All osteochondral lesions healed. CONCLUSION: Using K-wires for fixation of osteochondral lesions of the talus repair of the articular surface and stability of the lesion can be achieved even in unstable chronic lesions.

[The modular hip revision stem made of titanium alloy--influence and optimisation of bending stiffness]. / Modulare Hüftrevisionsschäfte auf Titanbasis--Einfluss und Optimierung des Steifigkeitsverhaltens.

UNLABELLED: The MRP-Titan Revision stem has proved to be a highly successful implant system for revision arthroplasty of the hip. Good and excellent clinical and radiological results with spontaneous filling of bony defects have been reported, The observation of atrophy of the proximal femur associated with stem diameters > 17mm prompted us to examine the bending stiffness of stems of various diameters. To determine their static bending characteristics, the stems were tested under axial pressure loads in accordance with Euler's buckling case. Dynamic tests were performed with the mono-axial servohydraulic test equipment MTS 810. From a stem diameter of 18 mm upwards, deflection of the stem under loading decreased disproportionately, in direct correlation with the stem stiffness. By optimising the geometry and varying the alloy it is possible to obtain a constant ISD factor for the modular MRP-Titan revision stem CONCLUSION: The MRP-Titan revision stem is a reliable implant system for revision arthroplasty of the hip. Clinical findings of atrophy of the proximal femur associated with stem diameters > 17 mm was found to be correlated with a disproportionate increase in bending stiffness. The aim of further developments will be to reduce the stiffness of larger-diameter stems by making changes to the design and/or to the alloy (Ti15Mo, Ti13Nb13Zr, Ti12Mo6Zr2Fe2).

[Femoral nerve palsy due to excessive granuloma in aseptic cup loosening in cementless total hip arthroplasty]. / Femoralisparese wegen ausgeprägter Granulombildung bei aseptischer Pfannenlockerung einer zementfreien Hüftendoprothese.

AIM: Femoral nerve palsy after total hip arthroplasty can result from several causes. Delayed neuropathies of the femoral nerve because of excessive granuloma in loosened implants are a rare condition. CASE REPORT: We report the case of delayed neuropathy of the femoral nerve after cementless total hip arthroplasty because of aseptic loosening of the cup. Electrophysiologic evaluation revealed a severe lesion of the femoral nerve with sensomotoric deficits. An abdominopelvic computed tomography (CT) scan revealed an excessive granuloma with a large intrapelvic portion. After revision of the loosened acetabular component and the femoral nerve and removal of the granuloma the neurologic symptoms improved. CONCLUSION: Regular (1-2 years) clinical and radiological follow-ups are requested after total hip arthroplasty to prevent excessive loosening of implants, excessive granuloma and severe sequelae like nerve damage.

[Arthrodesis of the hip and its conversion]. / Die Arthrodese des Hüftgelenks und ihre Remobilisation.

Arthrodesis of the hip used to be an important means of treating painful and damaged hips. Increasing experiences in total hip replacement have led to restrictive indications for arthrodesis and to more and more total hip arthroplasty. Hip arthrodesis has limited indications today. It remains the treatment of choice in deteriorated, painful hip joints, especially in the case of contraindications and severe muscular deficits. The best position of the fused hip is 10 to 25 degrees flexion, 0 to 15 degrees external rotation, 0 to 10 degrees abduction or 0 to 6 degrees adduction. The aim of the operation is a stable osteosynthesis which allows early mobilisation of the patient. Disturbances in walking patterns, mechanical overloading of neighbouring joints, such as the lumbar spine, ipsilateral knee or contralateral hip, often support a conversion from arthrodesis to total hip arthroplasty. The aim of the primary operation, therefore, is the preservation of the stabilizing pelvitrochanteric muscles and their insertions.

[Titanium deposits on the ceramic heads of dislocated total hip replacements]. / Titanauflagerungen auf Keramikköpfen bei luxierten Hüftendoprothesen.

INTRODUCTION: In cases of revision total hip replacement (THR) having acetabular titanium components with dislocations in the past, metallic deposits are frequently found on the ceramic heads. The aim of this study was to determine whether the metallic deposits increase surface roughness in definite areas. MATERIALS AND METHODS: Ten ceramic heads of revised THR which showed metallic deposits were investigated. The patients suffered from one to six dislocations. The prosthesis lifetime ranged from 2 weeks to 12 years. Surface structure was investigated in a scanning electron microscope (LEO 1525), and the metallic deposits characterised by means of energy dispersive x-ray analysis (EDX). RESULTS: In the area of the metallic deposits, titanium was detected by EDX. Edges with a significant increase in surface roughness were observed, partially accompanied by damage to the surface structure and loosening of Al(2)O(3) particles. DISCUSSION: Titanium deposits increase surface roughness in definite areas, which probably causes wear to the ceramic-ceramic or ceramic-polyethylene articulations due to different roughness values and surface properties. Further investigations are necessary in order to determine the importance of these findings with respect to wear and loosening of total hip arthroplasty.

[Surface characterisation of shot peened implants with glas beads in total hip arthroplasty]. / Oberflächenuntersuchungen an Glaskugel-gestrahlten Titanimplantaten in der Hüftendoprothetik.

UNLABELLED: Alumina-blasting is used to create a rougher surface of Titanium implants in cementless total hip arthroplasty to achieve a better bony ingrowth. An increasing number of publications in maxillofacial surgery and orthopaedic surgery show that there is a significant contamination in Alumina blasted surfaces. Latest research published an effect of contaminant particles on early loosening of endoprostheses associated with third body wear. Due to our knowledge no previous study analysed surface contamination of hip endoprostheses with glass beads. Aim of our work was to evaluate the percentage of contaminated surface of hip endoprostheses with glass beads. MATERIAL AND METHOD: The surface of 5 Ti-VPS sprayed Phoenix cups and 5 morse-taper-junctions of the MRP-Titan revision stem (Peter Brehm, Chirurgie Mechanik, Weisendorf) were analysed with respect to glass particles. Shot peening was performed with glass beads "BALLOTINI" MGL, Fa. Würth Strahlmittel. A field emission scanning electron microscopy (LEO 1525) was used for the detection of the glass-particles on the implant surface with a backscattered electron detector. The particle covering position was calculated by means of an imaging analyze software (analySIS, Soft Imaging System GmbH). RESULTS: The surface of the Ti-VPS sprayed Phoenix cups showed a contaminated area at a mean of 9.2 +/- 1.3 %, morse-taper-junctions of the MRP-Titan stem at a mean of 9.6 +/- 2.1 % with glass particle contact. DISCUSSION: The results of this study clearly show that there is a contamination of shot pinned Titanium surfaces with glass particles in a significant percentage. With respect to third body wear in total hip arthroplasty further studies are necessary to minimize contamination.

[Surface characterization of Al2O3-blasted titanium implants in total hip arthroplasty]. / Oberflächenuntersuchungen an Al2O3-raugestrahlten Titanimplantaten in der Hüftendoprothetik.

INTRODUCTION: Shot peening and grit blasting techniques are used in several surface modifications for producing hip endoprostheses. Corund blasting techniques using highly pure Al2O3 particles to create a rough surface of titanium implants in cementless total hip arthroplasty achieve better osteointegration. An increasing number of publications in maxillofacial surgery and orthopedic surgery show that there is a significant contamination on corund-blasted surfaces. The latest research studies reported an effect of contaminant particles on early failure of endoprostheses associated with third body wear. The aim of our work was to evaluate the amount and particle size of Al2O3 on the implant surface. MATERIAL AND METHOD: The surface of four different geometries (five parts each, ARR titanium acetabular reinforcement ring, anisotropic Vektor cup, Vektor titanium stem and modular MRP Titan stem) were analyzed with respect to Al2O3 particles. Grit blasting was performed with Al2O3 particles, Alodur SWSK, Fa. Treibacher. Field emission scanning electron microscopy (LEO 1525) was used for the detection of the Al2O3 particles at the implant surface with a backscattered electron detector. The particle size distribution as well as the average area of the covered surface was calculated with image analyzing software (analySIS, Soft Imaging System GmbH). RESULTS: The surface of the anisotropic Vektor cup was contaminated at an average of 41.7+/-4.9%, the Vektor titanium stem at an average of 33.3+/-4.7%, the (MRP) Titan stem at an average of 30.6+/-4.2%, and the ARR titanium acetabular reinforcement ring at an average of 23.2+/-1.6 with Al2O3 particles over the whole surface orientated to the bone. DISCUSSION: The results of this study clearly show that there is contamination of rough titanium surfaces with Al2O3 particles at an unexpectedly high percentage. With respect to third body wear in total hip arthroplasty, further studies are necessary to minimize contamination of roughened surfaces and maintain sufficient roughness for osteointegration.

[Delayed paresis of the femoral nerve after total hip arthroplasty associated with hereditary neuropathy with liability to pressure palsies (HNPP)]. / Tomakulöse Neuropathie (HNPP) als Ursache einer verzögerten Parese des N. femoralis nach Hüfttotalendoprothesenimplantation.

Delayed lesions of the femoral or sciatic nerve are a rare complication after total hip arthroplasty. Several cases in association with cement edges, scar tissue, broken cerclages, deep hematoma, or reinforcement rings have been published. We report about a 62-year-old female who developed a pure motor paresis of the quadriceps muscle 2 weeks after total hip arthroplasty. After electrophysiological evaluation had revealed an isolated femoral nerve lesion, revision of the femoral nerve was performed. During operative revision no pathologic findings could be seen. One week later the patient developed paralysis of the left wrist and finger extensors after using crutches. Electrophysiological evaluation revealed several nerve conduction blocks in physiological entrapments and the diagnosis of hereditary neuropathy with liability to pressure palsies (HNPP) was established. Hereditary neuropathy with liability to pressure palsies (HNPP) is a rare disease with increased vulnerability of the peripheral nerve system with mostly reversible sensorimotor deficits. It should be taken into consideration in cases of atypical findings of compression syndromes of peripheral nerves or delayed neuropathy, e. g., after total hip arthroplasty.