With the exception of the Hill-Sachs interval, CT and MRI show no significant differences in the diagnostic value of the HSL measurement regardless of the measurement technique.

PURPOSE: The aim of the current study was to compare the diagnostic precision and reliability of different methods in measuring Hill-Sachs lesions (HSLs) using MRI and CT. METHODS: A total of 80 consecutive patients with a history of anterior shoulder instability were retrospectively included. The preoperative CT and MRI scans of the affected shoulders were analysed. To investigate the ability of the Franceschi grading, Calandra classification, Richards, Hall, and Rowe grading scale, Flatow percentage and "glenoid track" assessment according to Di Giacomo et al. to quantify the extent of humeral bone loss, the results of each measurement method obtained with MRI were compared with those achieved with CT. In addition, the intra- and inter-rater reliabilities of each measurement method using CT and MRI were calculated and compared. RESULTS: A significant difference was found between CT and MRI in the determination of the Hill-Sachs interval (HSI) (p = 0.016), but not between the results of any of the other measurement techniques. With the exceptions of the Franceschi grade and Calandra classification, all measurement methods showed good or excellent intra- and inter-rater reliabilities for both MRI and CT. CONCLUSIONS: While the determination of the HSI with MRI was more accurate, all other analysed techniques for measuring the amount of humeral bone loss showed similar diagnostic precision. With regard to the intra- and inter-rater reliabilities, all measurement techniques analysed, with the exception of the Franceschi and Calandra classifications, provided good to very good reliabilities with both CT and MRI. LEVEL OF EVIDENCE: III.

Difficult to treat: are there organism-dependent differences and overall risk factors in success rates for two-stage knee revision?

OBJECTIVES: Failure after two-stage procedure for periprosthetic joint infection (PJI) is a rare, but devastating complication. Some authors assume a correlation of underlying organisms and recurrence rate. Methicillin-resistant Staphylococci (MRS) and other organisms (quinolone-resistant Gram-negative bacteria, rifampicin-resistant Staphylococcus, Enterococcus, and Candida) are meant to be "difficult to treat" (DTT) with an inferior outcome for two-stage revision. In addition to the type of bacteria, some more risk factors seem to be present. The aim of this study was (1) to detect a difference of reinfection rates between reinfection-causing groups of bacteria ["difficult to treat" (DTT), "easy to treat" (ETT) and methicillin-resistant staphylococci (MRS)] after a two-stage procedure, and (2) find overall risk factors for reinfection in a standardized long (spacer insertion for at least 6 weeks) two-stage procedure for periprosthetic knee infection. METHODS: One hundred and thirty-seven two-stage revisions for periprosthetic knee infection were performed at one tertiary referral center. Finally, 96 patients could be included for analyses. Possible risk factors (comorbidities, prior surgery, etc.) and the types of organisms were documented. Quinolone-resistant Gram-negative bacteria, rifampicin-resistant Staphylococcus, Enterococcus, and Candida were classified as "difficult to treat" (DTT). Methicillin-resistant Staphylococci were summarized as "MRS", all other organism are summarized as "easy to treat" (ETT). Statistical analyses included univariate analysis (t test, Fisher's exact test, Chi square test) and logistic regression analysis. RESULTS: There were no statistical significant differences in recurrent infection rates between organism groups (DTT vs. ETT, p = 0.674; DTT vs. MRS, p = 0.705; ETT vs. MRS, p = 0.537). Risk factors seem to be "need of revision after first stage" (p = 0.019, OR 5.62) or completed second stage (p = 0.000, OR 29.07), numbers of surgeries (p = 0.028) and alcohol abuse (p = 0.019, OR 5.62). CONCLUSIONS: Revision needed during or after a two-stage exchange, numbers of surgeries and alcohol abuse are risk factors for recurrence, a different recurrence rates between organism-groups cannot be shown. The absence of significant differences in recurrence rates points to the importance of the individuality of each periprosthetic infection case: a reduction of necessary surgeries (with a thorough debridement, appropriate antibiotic addition to spacers) and the control of comorbidities (alcohol abuse) appear to be essential components of a two-stage exchange.

Outcome of Irrigation and Debridement after Failed Two-Stage Reimplantation for Periprosthetic Joint Infection.

INTRODUCTION: Two-stage revision is the gold standard for the treatment of deep implant infection after knee or hip arthroplasty. Irrigation and debridement may be a treatment option for failed 2-stage revisions in cases where a reinfection occurs within 30 days or the symptoms exist not longer than 3 weeks and is appealing because of its low morbidity. We determined the incidence of recurrent infections following irrigation and debridement for failed two-stage revision hip and knee arthroplasty. METHODS: We performed a single center retrospective review of periprosthetic hip and knee infections treated with a two-stage procedure from 2002 to 2010. All patients that subsequently underwent irrigation and debridement for a subsequent infection were selected for the current study. RESULTS: 440 two-stage revisions were performed between 2002 and 2010. Fifty-one two-stage revisions failed (11.6%). Nineteen failed two-stage revisions were treated with irrigation and debridement; 12 (63.2%) patients remained free of infection at follow-up (mean follow-up: 39 months; range, 24-90 months), infection persisted in 6 patients (31.6%), and 1 patient died (5.3%). CONCLUSIONS: Success rates of irrigation and debridement for failed two-stage procedures are similar to the success rates of irrigation and debridement in primary implant infections. According to the current paper, irrigation and debridement are an acceptable treatment for acute reinfections after failed two-stage revision if performed within the first 30 postoperative days after failed two-stage procedure or if symptoms are present for less than 3 weeks in the presence of a susceptible organism.

Translation, validation, and cross-cultural adaption of the Western Ontario Meniscal Evaluation Tool (WOMET) into German.

PURPOSE: The Western Ontario Meniscal Evaluation Tool (WOMET) was developed in order to investigate the health-related quality of life of patients with meniscal pathologies. The aim of the present study was to translate and validate the WOMET into German. METHODS: A standardized forward backward translation of the WOMET into German was first performed. One hundred ninety-two patients with isolated meniscal tears completed the German version of the WOMET as well as the Western Ontario McMasters University Arthritis Index, and the Knee Osteoarthritis Outcome Score. Furthermore, reliability, construct validity, feasibility, internal consistency, ceiling, and floor effects were then calculated. RESULTS: Excellent feasibility (85.4% fully complete questionnaire), internal consistency (Cronbach's α = 0.92), and test-retest reliability (ICC, r = 0.90) were found. The standard error of measurement and the minimal detectable change were ±4.6 and 12.7 points, respectively. All predefined hypothesises were confirmed. No floor or ceiling effects were found. CONCLUSIONS: The presented German version of the WOMET is a valid and reliable tool for investigating the health-related quality of life of German-speaking patients with meniscal pathologies. LEVEL OF EVIDENCE: Cross-sectional study, Level II.

[Large Hibernoma of the Proximal Upper Arm and the Axilla - Literature Review and Case Description of a Very Rare Benign Soft Tissue Tumor]. / Großes Hibernom des proximalen Oberarms und der Axilla ­ Literaturüberblick und Fallbeschreibung eines sehr seltenen gutartigen Weichteiltumors.

Hibernomas are very rare benign soft tissue tumors arising from brown fat. Malignant transformation or metastases are unknown. Males seems to be affected more often. Most patients are aged 20 to 40, but patients with intraosseous hibernomas are older. In children, hibernomas are extremely rare. The tumors grow slowly and have usually been present for a few years on presentation. Hibernomas are typically located on the thigh, neck, axilla or in the peri- und interscapular region. Diagnostic work-up in symptomatic hibernomas usually includes conventional X-ray and magnetic resonance tomography (MRI) with contrast medium. Asymptomatic hibernomas are often found accidentally in the diagnostic work-up of other diseases. Important differential diagnoses are lipomas, well differentiated liposarcomas, rhabdomyomas, granular cell tumors and sebeceous adenomas. Incisional biopsy should be performed to allow definitive histological diagnosis before definitive therapy. According to the literature, histologically preserved hibernomas can be removed with curative intention and marginal resection. After complete tumor removal, local recurrence has not been described. The following article describes the case of a large hibernoma of the proximal arm, involving the axilla, and describes the epidemiology, clinical behavior, diagnostic work-up, therapy and prognosis of this very rare benign fatty soft tissue tumor, on the basis of a review of current literature.

[Acetabular Osteolysis in Total Hip Replacement - When to Retain the Cup?]. / Azetabuläre Osteolysen bei Hüfttotalendoprothese - wann kann die Pfanne belassen werden?

Periacetabular osteolysis is a frequent long-term complication of cementless total hip arthroplasty. The decision whether to retain or to revise a cup in the presence of osteolysis remains a challenge. The options are regular clinical and radiological check-ups, isolated liner exchange with and without bone grafting, and complete cup revision. Thorough preoperative diagnostics, including a medical history, examination and imaging, are mandatory for correct decision making. In most patients, computed tomography is useful to assess periacetabular osteolysis. If the cup is well-fixed and positioned in an asymptomatic patient without progressive osteolysis and no implant defect or higher grade polyethylene wear and no signs of infection, continuous clinical and radiological monitoring is preferred. If imaging reveals cup loosening, malposition, osteolysis localised in a weight-bearing area, imminent or present periprosthetic fractures, rapid progressive osteolysis, implant defects or massive inlay wear, surgical treatment may be preferred. Cup revision is usually performed in such patients. If the cup is well-positioned and well-fixed in the X-ray, the procedure has to be discussed with the patient individually. Apart from patient-specific risk factors, the risk of further progression has to be assessed. Isolated liner exchange can be performed if the patient is asymptomatic and the cup proves to be stable intraoperatively. It is still unclear whether filling osteolyses through screw holes or osseous windows is of long-term benefit.

[The Influence of Hearing Loss Represented by Standard Audiogram Types to Unaided APHAB Scores]. / Die Abhängigkeit von APHABu-Scores von Hörverlusten in Standardaudiogrammen.

BACKGROUND: Questionnaires as the APHAB (Abbreviated Profile of Hearing Aid Benefit) are besides pure-tone and speech-audiometry the third method of diagnostics in audiology. Up to now there has been no research on the influence of individual hearing loss, represented by standard audiograms, on the scores of the unaided APHAB (APHABu) done with a big number of subjects. This study will investigate whether there does exist such a relationship or not. METHODS: A total of 2 745 records provided by a database were analysed. First, the subjects' audiograms (air conduction) were allocated to 7 standardised audiogram types. By using a multivariant mixed linear model a potential connection was examined between these standard audiograms and particular APHABu scores for its four subscales: EC - ease of communication, BN - background noise, RV - reverberation, AV - aversiveness of sounds. RESULTS: There was no evidence for a dependency between any type of hearing loss dependence and unaided APHAB-scores. The values on the EC-scale vary between 49.8 and 58.0, on the BN-scale between 45.3 and 46.6, on the RV-scale between 44.4 and 52.4, and on the AV-scale between 47.6 and 50.1. DISCUSSION: This result confirms earlier studies with other questionnaires. Therefore, the APHABu can be used as an initial instrument for the diagnostics of individual hearing loss independently on whether hearing aids will be fitted subsequently or not.

Can the frontal tibiofemoral alignment be assessed on anteroposterior knee radiographs?

BACKGROUND: The aim of total knee arthroplasty is, amongst others, the reconstruction of a physiological axis of the leg with a tibiofemoral angle in the frontal plane of an average of 6°. The aim of this study is to clarify how much of the bone length on the femur and tibia has to be reproduced on anteroposterior (AP) knee radiographs in order to determine the leg's alignment after a total knee arthroplasty. MATERIALS AND METHODS: We analyzed the postoperative hip-to-ankle (HTA) radiographs of 100 patients who had undergone a total knee arthroplasty at our institution. RESULTS: There were strong correlations between the measured values on HTA and 20 cm bone length [lateral distal femur angle (LDFA) r = 0.887, medial proximal tibial angle (MPTA) r = 0.874, tibiofemoral angle (TFA) r = 0.888], but not between the measurements on HTA and 10 cm (LDFA r = 0.267, MPTA r = 0.102, TFA r = 0.161). There were significant differences between all measurements both on HTA and 20 cm and on HTA and 10 cm, with the exception of the LDFA between HTA and 10 cm (p = 0.085) and of the MPTA between HTA and 20 cm (p = 0.227). The intra- and inter-observer correlations were both high. CONCLUSION: If preoperatively crude axis deviations are excluded, the tibiofemoral angle on AP knee radiographs can be determined with an accuracy of ±2.6° if at least 20 cm length of bone is reproduced (measured from the femoral and tibial joint line). Due to the high 95 % confidence intervals and bearing in mind that deviations greater than 3° may lead to inferior clinical results, however, it appears inappropriate to determine lower limb alignment with anteroposterior radiographs. LEVEL OF EVIDENCE: Level 2.

The influence of frequency-dependent hearing loss to unaided APHAB scores.

Hearing loss can be measured by pure-tone and speech audiometry. The subjective hearing impairment can be assessed using questionnaires. The APHAB determines this for four typical hearing situations. It has not been researched previously whether a particular frequency-specific hearing loss leads to a particular unaided APHAB score in one of the subscales or not. Clarification could be helpful using the unaided APHAB as an instrument for primary diagnostics of hearing loss independently of whether hearing aids were subsequently fitted or not. A total of 4546 records from a database were analysed; the average age of the subjects was 69.3 years. Using a multivariant mixed linear model, a possible correlation was examined between a frequency-specific hearing loss (0.5-8.0 kHz) and particular unaided APHAB scores for its subscales. Furthermore, it was determined whether the subject's gender has a corresponding impact. There was no evidence of gender-specific dependence of the unaided APHAB scores. For the EC scale frequencies above 0.5 kHz, for the RV scale all frequencies and for the AV scale the frequencies at 1.0 and 2.0 kHz showed a significant correlation between hearing loss and the APHAB score. For each decibel of hearing loss there was an average rise in the APHAB score for the EC and RV scale of approximately 0.2 percentage points and an average decrease in the AV scale of 0.1 percentage points for each frequency. For the BN scale there was no evidence of this kind of correlation. The very varied possibility between individuals compensating for hearing loss in situations with background noises could be that there is no correlation between frequency-specific hearing loss and an associated unaided APHAB score. The described frequency-specific influence of hearing loss to the EC and RV score could be explained by fewer compensating possibilities for the patients in these specific hearing situations than for the BN scale described. Using the unaided APHAB form in primary diagnostics of hearing impairment is helpful for understanding individual problems.

Complications associated with 133 static, antibiotic-laden spacers after TKA.

PURPOSE: Periprosthetic infection after total knee arthroplasty (TKA) is a devastating complication, with a two-stage revision currently the 'gold standard' treatment for chronic infections. There is, however, a lack of information about mechanical complications during this treatment. The purpose of this study was to determine: (1) the rate and type of mechanical complications encountered during a two-stage exchange revision for periprosthetic infection of the knee and (2) possible factors of influence. METHODS: Between 2000 and 2011, 133 patients received an antibiotic-laden cement spacer as part of a two-stage protocol. The overall frequency and types of complication were recorded (fissure/fracture of the tibia or femur, spacer fracture, subluxation of the patella, peroneus affection, wound healing disorder and mobilization under anaesthesia based on a constricted ROM). Also analysed were potential influencing factors (BMI, ASA classification, length of the interval with the enclosed spacer, revision needed after explantation, revision needed after reimplantation, complications after primary TKA, service life of the primary prosthesis) in terms of the overall outcome (possibility of reimplantation, complications during the two-stage protocol). RESULTS: The mean age at the time of the first stage operation was 70.1 ± 9.9 years. Overall, 20 of 133 patients suffered one of the complications mentioned above (15 %). Fracture/fissure of the tibia occurred in nine cases (6.8 %) and fracture/fissure of the femur in three (2.3 %). There were also three mobilizations under anaesthesia after TKA reimplantation, two affections of the peroneus nerve, one spacer fracture, one subluxation of the patella and one wound healing disorder. The influencing factors on the overall outcome were revision after reimplantation (reinfection, p = 0.002), revision after explantation (reinfection, p = 0.044), prior aseptic revision after primary TKA (reimplantation, p = 0.019), and prior two-stage revision (reimplantation, p = 0.002). CONCLUSION: A two-stage revision arthroplasty using a static cement spacer is an effective therapy for infected TKAs. The complication rate of 15 % (including restricted ROM after reimplantation) is acceptable. Influencing factors (revision needed after reimplantation, revision needed after explantation) can be demonstrated and should be avoided during the two-stage protocol.

Can rotational alignment of total knee arthroplasty be measured on MRI?

BACKGROUND AND PURPOSE: The aim of this study was to investigate the potential of MRI to determine rotational alignment after TKA in comparison to the gold standard, CT. METHODS: Rotational alignment was measured in the transverse plane on CT and MR-images in 14 patients prior to TKA revision. Differences between CT and MRI measurements were analysed. RESULTS: There was a strong correlation between CT and MRI measurements for both the tibial (r = 0.929) and femoral (r = 0.942) components with a mean difference of 0.47 ± 1.3 and 0.13 ± 3.2 degrees, respectively. INTERPRETATION: Despite artefact formation, it can be concluded that the rotational alignment of metallic TKA components can be measured by MRI as accurately as by CT.

[Retention of the prosthesis in early periprosthetic infection after total hip arthroplasty]. / Gelenkerhalt bei Frühinfektion nach Hüfttotalendoprothese.

BACKGROUND: The rate of periprosthetic infection after total hip arthroplasty (THA) without patient-specific risk factors is about 1 %. The therapeutic challenges are control of infection, restoration of hip function and prevention of reinfection. In early infection, "irrigation and debridement" (I&D) with exchange of mobile components and retention of the prosthesis remains an attractive alternative to one- or two-stage revision. However, variable results have been reported in the literature. Recent studies have shown new algorithms of treatment for early infection and acute haematogenous infection after THA. PATIENTS AND METHODS: Recent therapeutic algorithms for early infections after THA and an overview of the literature are presented. We conducted a retrospective analysis of 73 patients with early postoperative infection or acute haematogenous infection (symptoms shorter than 4 weeks) after THA who were treated with I&D, exchange of mobile components and retention of the prosthesis at our hospital between 2002 and 2011. RESULTS: RESULTS from the recent literature have shown that the treatment concept of prosthetic retention can only be successful within a maximum time of symptoms of 3 weeks in cases of haematogenous infection and a maximum time span of 4 weeks after index operation in cases of early infection. In our retrospective study with 73 patients, the treatment was successful (free of infection) in 46 patients (63 %). A persistence of infection occurred in 27 patients (37 %). "Difficult to treat" bacteria were present in 28.8 % of the patients. CONCLUSION: The concept of irrigation and debridement with retention of the prosthesis is a valuable alternative to one- or two-stage revision THA, if a maximum time of 4 weeks after index operation in early infections and a maximum time of symptoms of 3 weeks in haematogenous infections are not exceeded. However, reinfection rates after I&D are higher than after two-stage procedures. Prerequisites for success of the I&D algorithm are a stable prosthesis, operable soft tissues, and germs susceptible to antibiotic treatment.

[Accuracy of hip stem migration measurement on plain radiographs: reliability of bony and prosthetic landmarks]. / Erkennung von Hüftschaftsinterungen am Röntgenbild: Reliabilitätsuntersuchung knöcherner und prothetischer Landmarken.

BACKGROUND: In Germany, more than 150,000 total hip arthroplasties (THA) are performed annually. Early implant migration is supposed to be the best indicator for mechanical failure of femoral stems. Therefore, radiological evaluation of hip stems is routinely done by analyzing plain radiographs of THA. OBJECTIVES: The purpose of this study was to evaluate the accuracy of implant migration measurement on plain radiographs. MATERIAL AND METHODS: Two observers analyzed 44 anterior-posterior radiographs of the pelvis in 22 pain-free patients at least 2 years after implantation of an anatomical hip stem. The evaluation was performed on digital as well as conventional plain radiographs. Intraobserver reliability was analyzed by double measurements of each radiograph and the evaluation of the consecutive series of each patient. The anatomical structures of interest were the greater trochanter and the minor trochanter. Furthermore, the tip of the prosthesis, the shoulder of the implant, and the center of rotation were determined. RESULTS: The conventional measurement technique proved higher accuracy compared to the digital measurement technique. The best anatomical structure was the greater trochanter in the conventional technique and the minor trochanter in the digital technique. The best reference structure with regard to the implant was the shoulder of the prosthesis for both techniques. CONCLUSION: The recommended reference structures for the evaluation of implant migration on plain radiographs are the greater trochanter and the shoulder of the implant for the conventional measurement technique and the minor trochanter and the shoulder of the implant for the digital technique. Migration of an implant should not assumed before a determined difference of 2 mm.

[Development and use of an APHAB database]. / Entwicklung und Anwendung einer APHAB-Datenbank.

A specific quality assurance questionnaire concerned with the provision of hearing aids was introduced that assesses elements of patient satisfaction within Germany's statutory healthcare system. A questionnaire-based assessment is now relevant for all physicians involved in the care of statutorily insured patients in Germany. The APHAB (Abbreviated Profile of Hearing Aid Benefit) questionnaire is the most widely used. The APHAB assesses several different situations: the normal hearing situation, hearing in noise, comprehension of speech in situations of echo or reverberation and hearing in loud situations. The APHAB questionnaire-based patient evaluation of the benefit of hearing aids represents the third pillar of audiological diagnostics, alongside classical pure-tone and speech audiometry. The objective of the APHAB database is to allow evaluation of individual patient data on the basis of a larger volume of data.

[Osteoarthritis of the knee in the young patient--who should receive total knee arthroplasty and who should not?]. / Die Gonarthrose des jüngeren Patienten--wen sollte man knieendoprothetisch versorgen, wen nicht?

The incidence of total knee arthroplasty in young patients continues to rise in certain countries despite evidence of decreased patient satisfaction and increased likelihood for revision in patients 55 years of age or less. As long as sufficient pain relief and functional improvement can be obtained by alternative means, total knee arthroplasty should be avoided whenever possible. In young patients with unicompartmental osteoarthritis, and a partially conserved joint space, correctional osteotomy around the knee accompanied by cartilage surgery should be preferred in the presence of the respective deformity. In cases of advanced unicompartmental arthritis, unicompartmental arthroplasty should be considered even in younger patients. Only if advanced arthritic changes in more than one compartment or accompanying tibiofemoral instability are present in younger patients, is total knee arthroplasty indicated in selected cases. The strongest predictor of satisfaction even in younger patients is, however, a realistic expectation about the outcome of surgery.

Can the tibial slope be measured on lateral knee radiographs?

PURPOSE: The posterior tibial slope influences both the natural knee stability as well as the stability and kinematics after total knee arthroplasty (TKA). Exact definition of the posterior tibial slope (PTS) requires lateral radiographs of the lower limb. Only lateral knee radiographs are routinely obtained after TKA, however. The purpose of the present study therefore was to analyse the relationship between PTS measurement results on short and expanded lateral knee radiographs. METHODS: The PTS was measured on 100 consecutive lateral radiographs of the lower limb using the mechanical and three diaphyseal axes with various distances below the tibial plateau. RESULTS: Significant differences between PTS results were found for all three diaphyseal axes, with the smallest differences and the strongest correlation for a diaphyseal axis at 16 and 20 cm below the tibial plateau. Using short distances below the tibial plateau (6 and 10 cm) resulted in an overestimation of the PTS of 3°, on average. CONCLUSION: The PTS measurements in long lateral knee radiographs are more accurate compared to short radiographs. On short lateral knee radiographs, only a estimation of the PTS can be carried out. LEVEL OF EVIDENCE: Diagnostic study, Level II.

[Treatment of extensor mechanism rupture after total knee arthroplasty]. / Behandlung der Strecksehnenruptur bei liegender Knietotalendoprothese.

Disruption of the extensor mechanism is one of the most devastating complications in knee arthroplasty with a reported incidence between 0.17 and 2.5 %. Due to a high rate of subsequent complications and poor clinical results, every effort should be made to avoid extensor mechanism disruption. In cases of disruption however, the orthopaedic surgeons must be aware of non-operative and surgical treatment options and their indications, timing, outcome and limitations. Non-operative treatment is feasible in cases of incomplete disruption of the quadriceps tendon with an extension deficit of less than 20°. Complete disruption of the quadriceps tendon or rupture of the patellar tendon should be treated operatively. Therapeutic strategies include direct repair of the tendon in acute disruption without retraction. Retraction as well as soft tissue damage necessitates augmentation of the tendon. Frequently used endogenous augments are the semitendinosus tendon as well as the gastrocnemius muscle. Exogenous options are allografts of the Achilles tendon or structured extensor mechanism grafts and synthetic augments to support endogenous tendon repair. The clinical results after extensor mechanism failure following total knee arthroplasty are less favourable compared to ruptures in native knee joints. The most common complications are postoperative stretching and the maintenance of an active extensor lag.

[Cost-effectiveness of a local bone bank based on thermodisinfection according to § 20 b and c AMG and alternatives]. / Zulassung einer lokalen Knochenbank nach § 20 b und c AMG und Einführung einer Thermodesinfektion: Lohnt sich der Aufwand?

INTRODUCTION: The German tissue law creates a different and more difficult situation for German musculoskeletal tissue banks. The objective aim of the new regulations was an increased safety and a reduction of viral and non-viral disease transmissions. In the authors' case, the government officials demanded a thermodisinfection for human femur heads. As a consequence of the requirements we aimed at an analysis of the cost-effectiveness of an admission according to § 20 b and c "Arzneimittelgesetz" (AMG) and implementation of the "lobator bonebank system™". METHOD: We calculated the working hour requirements for all medical staff involved in the tissue procedure. Additional costs were the current consumptions of two freezers (cooling power - 80 °C) for one year, the current consumption of one thermodisinfection process, the material cost of one disinfection and documentation set, expenses for laboratory examinations and the non-recurrent expenses for the admission according to § 20 b and c AMG and the "lobator bonebank system". Non-recurrent expenses were calculated for five years according to 610 tissue donations. We compared the overall costs for one processed femur head with the charges of an industrial chemical treating and irradiation. RESULTS: Expenses for medical doctors were 14.13 € and for nurses 3.71 €. Energy costs were 15.20 € for each stored femur head. Costs for the disinfection and documentation sets were 105.15 €, laboratory expenses were 107.25 €. The non-recurring fee for the admission according to § 20 b and c AMG was 2650 €, the cost for the lobator-sd2 was 12 495 €. The overall expenses for one disinfected femur head were 274.82 € compared to 535.23 € in a tissue service. CONCLUSION: To comply with legal requirements, operating expenses of the new tissue act increased. Nevertheless we could still prove the cost-effectiveness of a local bone bank in Germany.

[Does the body mass index influence the results of revision total knee arthroplasty?]. / Hat der Body-Mass-Index Einfluss auf das Ergebnis nach Knieendoprothesenwechseln?

BACKGROUND: Revision total knee arthroplasty (TKA) is one of the most demanding as well as increasing orthopaedic operations. The influence of a higher body weight or body mass index (BMI) on the results of revision TKA is not evident so far. We therefore hypothesised that obesity as well as a high body weight could influence the results of revision TKA. PATIENTS: 75 consecutive revision TKA in 75 patients were included and stratified according to a BMI greater or smaller than 30 kg/m2 and a body weight greater or smaller than 90 kg. The Knee Society score (KSS), the function and the knee subscales were analysed pre- and postoperatively as well as the pre- to postoperative improvement. The duration of the procedure, the occurrence of complications, the blood loss and the length of hospital stay were collected. RESULTS: All patients showed a significant improvement of the KSS and function score (p < 0.05). There was a tendency to superior results in patients with a smaller BMI and a lower body weight. This tendency was most pronounced in the function subscale which depicted significant differences in favour of a BMI smaller 30 kg/m2. No significant differences were observed in the other analysed factors. CONCLUSION: BMI greater than 30 kg/m2 as well as a higher body weight seem to negatively influence the function of revision TKA. However, all patients significantly improved after revision TKA and no differences were found according to the occurrence of complications. Therefore, revision TKA should not be refused to obese or heavy patients.

[Validity of digital templating in total hip arthroplasty: impact of stem design and planner's experience]. / Validität der computergestützten Hüfttotalendoprothesenplanung: Einfluss von Schaftdesign und Untersuchererfahrung.

INTRODUCTION: Preoperative planning in total hip arthroplasty decreases the risk of implant oversizing and facilitates intraoperative orientation. The size of the acetabular and femural components can be estimated. The aim of the present study was to determine the validitiy of digital templating. Furthermore, we compared the accuracy of three planners with different clinical experience and the effect of two different femoral component designs on planning accuracy. METHODS: On 60 a. p. pelvis radiographs, 60 unilateral, non-cemented total hip arthroplasties using the planning tool "AGFA-Orthopaedic-Tools Version V2.10®" (Fa. Agfa Health Care, Mertsel, Belgium) were repeatedly planned by three orthopaedic surgeons (planner A fifth year, planner B third year, planner C second year of training). All 60 patients received pressfit acetabular components, a straight stem was implanted in 28 (CLS-Spotorno™, Fa. Zimmer) and a short stem (Fitmore™, Fa. Zimmer) in 32 patients. The planned sizes of the components and the offset-variations were compared to the implanted sizes. RESULTS: The percental accuracy and ICC planning for the straight stem were 42.9 %/0.906 for planner A, 39.3 %/0.833 for planner B, and 28.6 %/0.836 for planner C. Planning the short stem, the percental accuracy and ICC were 34.4 %/0,886 for planner A, 21.9 %/0.708 for planner B, and 12.5 %/0.681 for planner C. The accuracy and ICC of templating the acetabular components were 35 %/0.796 for planner A, 30 %/0.725 for planner B, and 26.8 %/0.511 for planner C. Planning the sizes of both femoral components showed significant differences between planner A and C and planner B and C in Wilcoxon's signed-rank test. CONCLUSION: A lower level of experience showed no effect on the planning results of the acetabular components, but there were considerable and significant differences on planning the femoral components. Furthermore, the design of the femoral component had an impact on planning accuracy.