[Patient safety during endoprosthetic training : Does the training of surgeons in primary hip arthroplasty at certified endoprosthesis centres lead to increased complications?]

Hintergrund

Ziel der Studie war die Untersuchung, ob sich das perioperative Outcome und operationsspezifische Prozessgrößen bei Patienten mit Hüftgelenksersatz signifikant verschlechtern, wenn die Operation durch einen unerfahrenen Operateur, assistiert durch einen erfahrenen Operateur, im Kontext eines zertifizierten Endoprothesenzentrums durchgeführt wird.

Material und Methoden

Es wurden 1480 Patienten eingeschlossen, die zwischen 2013 und 2016 bei primärer Koxarthrose mit einer primären zementfreien Hüfttotalendoprothese (HTEP) versorgt wurden. Die relevanten Daten wurden retrospektiv aus dem Krankenhausinformationssystem, dem Entlassungsbrief und aus dem EndoCert-Bogen dokumentiert. Die Operateure wurden nach ihrer Qualifikation in erfahrene (Senior, > 50 HTEP pro Jahr) und unerfahrene Operateure (Junior, < 50 HTEP pro Jahr) unterteilt. Anschließend erfolgte der Vergleich der erhobenen Daten anhand dieser Unterteilung.

Resultate

Es zeigte sich bei unerfahrenen Operateuren eine signifikante Verlängerung der Operationsdauer um 20,7 min (Senior 62,6 ± 20,4 min; Junior 83,3 ± 19,5 min; p ≤ 0,001), der Krankenhausverweildauer um 0,25 Tage (Senior 8,8 ± 0,9 d; Junior 9,0 ± 0,9 d; p ≤ 0,001) und eine Erhöhung der Transfusionshäufigkeit von Erythrozytenkonzentraten (Senior 0,6 ± 1,1 Stk.; Junior 0,9 ± 1,4 Stk.; p ≤ 0,001). Dagegen zeigte sich kein Unterschied bei perioperativen Komplikationen (p = 0,682) und beim perioperativen Blutverlust (Senior 1,3 ± 0,5 l; Junior 1,3 ± 0,5 l; p = 0,097). Zwischen Operationsdauer und Blutverlust bestand allerdings eine positive Korrelation (Senior r = 0,183; Junior r = 0,214; jeweils p ≤ 0,01).

Schlussfolgerung

Die Ausbildung von unerfahrenen Operateuren an einem zertifizierten Endoprothesenzentrum führt bei Assistenz durch erfahrene Operateure nicht zur Reduktion der Patientensicherheit mit vermehrten Komplikationen. Aufgrund der Operationszeitverlängerung kommt es allerdings zu einer Mehrbelastung der Kliniken im Wettbewerb mit nichtausbildenden Kliniken, die nicht im DRG-System abgebildet ist.

[Recommendations for unicondylar knee replacement in the course of time : A current inventory]

BACKGROUND

A higher patient satisfaction stands in contrast to higher revision rates of unicondylar knee joint endoprosthetics (UKE) compared to total knee joint endoprosthetics (TKE). Furthermore, old "dogmas" regarding indications and contraindications persist, which is still reflected in the significantly different case numbers.

AIM

The aim of this article is to provide an overview of the current literature regarding 1. indication and contraindication (BMI, age, sport, arthrosis of other compartments, ligament status) and 2. the "eternal rival" fixed or mobile bearing for UKE.

RESULTS

The choice of the right patient remains essential, even if all the old "dogmas" of contraindications have been relativized or even outdated. Arthroses of the contralateral (in medial UKE correspondingly lateral) compartment and advanced arthroses of the lateral patella facet remain the only persistent contraindications. In contrast, a high BMI, age, chondrocalcinosis, medial patella facet and a defective (but particularly functionally stable) ACL are not contraindications; however, severe obesity is responsible for a significantly higher complication rate and probably a higher rate of loosening. Rather, the experience and thus the number of UKEs of the individual surgeon is decisive for the outcome, to which the discussion about mobile or fixed inlays must also be completely subordinated.

CONCLUSION

The indications for UKE can, therefore, be extended with a clear conscience on the basis of literature, and the current 1:10 UKE:TKE ratio in Germany can be shifted significantly.

Sodium hypochlorite is more effective than chlorhexidine for eradication of bacterial biofilm of staphylococci and Pseudomonas aeruginosa

PURPOSE

Periprosthetic infection is a common reason for surgical revision. Given the increasing resistance of bacteria to antibiotics (e.g., VRE, 4-MRGN) local antiseptic treatment is gaining in importance. However, no standard guideline-based treatment recommendation is yet available. The aim of this study was to investigate the effectiveness of sodium hypochlorite and chlorhexidine against bacterial biofilms. Furthermore, the toxicity of both antiseptics towards human chondrocytes was examined.

METHODS

Human chondrocytes were isolated, cultivated and treated with sodium hypochlorite and chlorhexidine. The viability of cultures was assessed by determination of cell count, XTT and MTT ELISAs, and fluorescent staining with propidium iodide. Bacterial strains of Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa were added to liquid media and incubated overnight. After determination of bacterial concentrations polyethylene (PE) devices were inoculated with bacteria for 48 h until biofilms formed. The devices were then washed, treated with antiseptics for 2 and 5 min and subsequently spread on agar plates.

RESULTS

Sodium hypochlorite is more effective than chlorhexidine in penetrating biofilms of S. aureus, S. epidermidis and P. aeruginosa. Both antiseptics are chondrotoxic, but sodium hypochlorite damages human chondrocytes less than chlorhexidine in vitro.

CONCLUSIONS

The findings confirm the effectiveness of sodium hypochlorite and chlorhexidine against bacterial biofilms. Both antiseptics can be recommended for the treatment of periprosthetic infections. The toxic effects of sodium hypochlorite and chlorhexidine towards chondrocytes may mean there is a risk of damage to cartilage tissue.

LEVEL OF EVIDENCE

Controlled experimental study.

[Implantation of a tantalum patella during revision surgery]

OBJECTIVE

The reconstruction or restoration of a functioning patella for active extension and flexion by implantation of a tantalum patella. In spite of larger osseous defects of the patella, the goal is to achieve sufficient extensor mechanism function.

INDICATIONS

Patients who have such a large bone defect in the area of the patella that implantation of a traditional patella replacement is not possible. In addition, patients with a peri-implant fracture of the patella can be treated with a tantalum patella and additional plate osteosynthesis.

CONTRAINDICATIONS

Absence of a cortical basic structure of the patella. Complete loss of the patella or the extensor mechanism. Periprosthetic infection.

SURGICAL TECHNIQUE

The patella is completely excised. Subsequently, the back surface of the patella is milled to anchor the tantalum structure as accurately as possible without cement. This is fixed circularly after desired positioning by means of nonresorbable suture. Finally, the polyethylene back surface replacement is cemented onto the back surface of the tantalum structure.

POSTOPERATIVE MANAGEMENT

The patients have a limitation of flexion of 0-0-90° at 20 kilogram partial weight bearing for 12 weeks after surgery.

RESULTS

A total of 10 patients who received a tantalum patella between 2013 and 2019 were retrospectively included. A tantalum patella was implanted in 9 patients with a large patellar defect. In one case a tantalum patella with additional plate osteosynthesis was implanted to treat a peri-implant fracture of the patella. Loosening of the tantalum patella was observed in 1 patient, while in another patient postoperative arthrofibrosis was observed. In 2 cases a postoperative superficial wound healing disorder was detected. Two patients had a persistent infection with subsequent complete explantation of the prosthesis.

Low-grade infections as a possible cause of arthrofibrosis after total knee arthroplasty

Purpose

Arthrofibrosis after total knee arthroplasty represents a considerable burden for the patient and a therapeutic challenge for the practitioner. One possible cause discussed in the literature is a low-grade infection. This hypothesis should be examined within the scope of this retrospective study.

Patients and methods

Nineteen patients with clinical symptoms of arthrofibrosis after primary total knee arthroplasty were examined between January, 1999 and January, 2012. Incorrect positioning was radiologically ruled out. All patients were examined clinically (score of Freeman as well as Blauth and Jäger), radiologically (component and leg alignment, patella height according to Insall and Salvati), microbiologically (culture-based procedures), molecular biologically (PCR) and histologically in the course of an open revision of the prosthesis.

Results

According to the score of Freeman et al. (1977), a highly significant improvement in pain (p = 0.007) and in the overall score (p = 0.003) was shown. The knee joint mobility did not change significantly (p = 0.795). PCR was negative in 17 patients. One patient showed a PCR-positive result of the synovial membrane for Corynebacterium spp., while Staphylococcus warneri was detected in the culture. Another patient had a positive result of synovia PCR for Enterococcus cecorum as well as Corynebacterium spp. However, this culture was sterile. In 16 patient samples, no bacterial growth was detectable. Two samples were not evaluable. The main histopathological findings were synovialitis and fibrosis.

Conclusion

The hypothesis of low-grade-infection-induced arthrofibrosis after total knee arthroplasty could not be confirmed in this study. However, based on this small study population the conclusion needs to be confirmed by new and larger studies, ideally prospectively designed including a control group.

Calcaneal Displacement Osteotomies - Less Soft Tissue Irritation in Lateral Compression Plate than Screws

PURPOSE OF THE STUDY With the concept of the lateral compression plate (LLCP) a technique has been available designed to combine the advantages of a fixed-angle fixation with a complete sinking of the implant into the proximal bone. The objective of the present study was to investigate the results of the LLCP compared with classical screw osteosynthesis (SO). MATERIAL AND METHODS 31 patients with pes planovalgus who received calcaneal displacement osteotomy and osteosyntheses with screws (n = 17) or LLCP (n = 14) between 2010 and 2015 were investigated retrospectively.The ankle-hindfoot scale, Kaikkonen score, VAS, and the SF-36 were determined preoperatively as well as at the last clinical follow-up. In addition, a radiological control of osseous integration was performed in all patients 12 weeks after surgery. RESULTS With regard to clinical scores both methods depicted significant improvement. In the overall cohort there were no pseudarthroses. In the SO group 5 cases (29%) showed hardware irritation, in the LLCP group there were none. Results in the LLCP group were significantly superior in the area of the physical section of the SF 36. CONCLUSIONS Based on the results of our study, surgical treatment of stage II pes planovalgus by means of calcaneal displacement osteotomy using the LLCP is equivalent to SO with a lower incidence of hardware irritation. Key words:pes planovalgus, lateral compression plate, osteosynthesis, screw, hardware irritation.

LEVEL OF EVIDENCE

Level IV, retrospective case serie.

Gait Analysis before and after Cycle Training Using a 3D Pedal System

PURPOSE OF THE STUDY In this pilot study, gait analysis was performed before and after training with a 3D pedal system (BIUS1), in order to clarify whether these differences are detectable by gait analysis after a short period of training. MATERIAL AND METHODS Two female and three male subjects were included in a prospective case-control pilot study. The patient and training characteristics were determined. Objective measurement data of the gait were obtained by using a three-dimensional motion analysis system with six infrared cameras and three force plates before and after training with the 3D pedal system. RESULTS The mean age was 36.7 ± 8.7 years and the subjects had a BMI of 21.8 ± 2.4 kg/m 2 . The training time per year was an average of 36.0 ± 11.2 days, with a training workload of 511.4 ± 36.7 km. For time-distance parameters, improvements for the left and right side were obtained for cadence and cycle time after training. In total, there was a reduction in hip abduction angle, and an increase in hip inward rotation, knee outward rotation, and range of the frontal knee angle. CONCLUSIONS Changes in parameters in the gait analysis after a short training interval demonstrate that a 3D pedal system is suitable to produce changes in the gait pattern detectable by gait analysis. Training effects on the supposedly weaker left side can be explained after a brief application of the BIUS1 system. Key words:cycle training, 3D pedal system, gait analysis.

Establishing an Interdisciplinary Compulsory Elective Subject 'Spine' in the Curriculum of the University Study Course of Human Medicine

PURPOSE OF THE STUDY Back pain and pathologies of the spine are among the main reasons why people consult a doctor, both general practitioners and paediatricians, as well as, specifically, orthopaedists, surgeons, and neurosurgeons. This involvement of different faculties calls for a high degree of interdisciplinary co-operation. In order to mediate these aspects of spine-specific diagnostics, therapy, and research to students during their studies and to promote up-and-coming specialists, the compulsory elective subject 'Spine' was established. MATERIAL AND METHODS From the winter semester of 2013 to the winter semester of 2014, the compulsory elective subject 'Spine' was offered to interested students in the 7th semester of their studies of human medicine. The maximum number of participants per course was 16. Each course lasted four weeks. The subjects taught covered the fields of degeneration, deformities, and destruction in the specialist disciplines of orthopaedics, traumatology, neurosurgery, and rehabilitation medicine. In addition, orthopaedic technology and the local musculoskeletal and biomechanical research institute were integrated into the course. Various teaching methods were applied, including problem oriented learning, seminars, observation or consultation, and internship. At the end, the course was evaluated with regard to subjective learning success, knowledge gain, satisfaction, and interdisciplinarity. Participants were compared with all students of the semester employing an objectively structured clinical examination (OSCE). RESULTS Forty-eight students took part in the compulsory elective subject 'Spine'. The compulsory elective subject was given a positive rating in all fields. In the learning success control, all of the students had good to very good results. Students attending the elective subject performed significantly better in the objective structured clinical examination (OSCE) (p ≤ 0.001). The compulsory elective course continues to be offered in the curriculum with a slightly altered schedule. CONCLUSIONS In view of the high prevalence of patients with back pain and its associated importance in terms of healthcare policy and social relevance, our experience leads us to recommend the general integration of such a compulsory elective subject in the study of human medicine. Key words:elective subject, spine, students, spinal disorders.

Long-Term Effects of Intravenous Iloprost Therapy in Patients with Bone Marrow Oedema of the Knee Joint

PURPOSE OF THE STUDY Bone marrow oedema (BMO) syndrome is a multifactorial condition. Various conservative treatment options include analgesic therapy, immobilisation of the affected joint and/or systemic intravenous iloprost therapy. Many studies have confirmed the positive effect of iloprost therapy, but only after short-term follow-up. The purpose of this study was to show that treatment with iloprost leads to positive long-term functional and radiological outcomes for BMO of the knee. MATERIAL AND METHODS Fifteen patients with BMO of the knee joint, ARCO stage 1-2, were included in this study. Various questionnaires, the Lysholm Score, the SF-36, WOMAC, Knee Society Score, and a visual analogue pain scale (VAS), were evaluated before and after iloprost therapy. All patients underwent MRI for radiological follow-up three months after treatment. RESULTS Significant improvements were found in the Lysholm Score, SF-36, WOMAC and KSS. In 80% of patients, follow-up MRI after three months showed complete regression of the oedema. Three patients received additional surgery after a follow-up period of 33 ± 7 months. CONCLUSIONS Based on the positive results of our study, we recommend treatment with iloprost for BMO of the knee in ARCO stage 1-2 patients. Key words:iloprost, bone marrow oedema, knee joint.

[Complications and costs in primary knee replacement surgery in an endoprosthetics centre : Influence of state of training]

BACKGROUND

This work examines the hypothesis that in endoprosthesis implantation there are differences between experienced primary and senior caregivers (S-Op) and less experienced follow-up assistants (T-Op) with respect to process-relevant parameters. The main hypothesis is that compared to S‑Op, T‑Op cause significantly longer surgery times and thus additional operating theatre costs. As sub-hypotheses, differences in various perioperative (p-o) parameters between T‑Op and S‑Op were examined.

MATERIALS AND METHODS

The status of the operator (senior and/or senior main operator [S-Op]) and/or postoperative CRP, perioperative blood loss, the amount of transfused erythrocyte concentrates, patient age, gender, ASA risk classification (American Society of Anesthesiologists), duration of surgery and blood transfusion, duration of inpatient stay, as well as the rates of early revision surgery and complications were recorded. A comparison of patients who had been operated by an S‑Op and those who had been operated by a T‑Op was made for all parameters.

RESULTS

Significant differences were found with respect to the duration of surgery, the duration of the hospital stay, and CRP on the third p‑o day. The T‑Op required an average of 11 min more than the S‑Op. CRP was significantly higher in the T‑Op group only on the third p‑o day, by 18 mg/l. In contrast, in the T‑Op group, a blood loss of 181 ml was lower than in the S‑Op group. This corresponded to a reduction of 0.26 transfused erythrocyte concentrates. There were no significant differences in complication rates between S‑Op and T‑Op.

DISCUSSION

In the setting of a certified endoprosthetics centre, the comparison of T‑Op with S‑Op showed that the use of the former with at a non-increased complication rate led to a significant extension of the operating time. This leads to additional training costs in the amount of an estimated 3% of the current DRG remuneration. These additional costs are not represented adequately in the current remuneration system.

A simple method of measuring the wear of explanted acetabular component inserts

Objectives

The determination of the volumetric polyethylene wear on explanted material requires complicated equipment, which is not available in many research institutions. Our aim in this study was to present and validate a method that only requires a set of polyetheretherketone balls and a laboratory balance to determine wear.

Methods

The insert to be measured was placed on a balance, and a ball of the appropriate diameter was inserted. The cavity remaining between the ball and insert caused by wear was filled with contrast medium and the weight of the contrast medium was recorded. The volume was calculated from the known density of the liquid. The precision, inter- and intraobserver reliability, were determined by four investigators on four days using nine inserts with specified wear (0.094 ml to 1.626 ml), and the intra-class correlation coefficient was calculated. The feasibility of using this method in routine clinical practice and the time required for measurement were tested on 84 explanted inserts by one investigator.

Results

In order to get the mean for all investigators and determinations, the deviation between the measured and specified wear was -0.08 ml (sd 0.12; -0.21 to 0.11). The interobserver reliability was 0.989 ml (95% confidence interval (CI) 0.964 to 0.997) and the intraobserver reliability was 0.941 for observer 1 (95% CI 0.846 to 0.985), 0.983 for observer 2 (95% CI 0.956 to 0.995), 0.939 for observer 3 (95% CI 0.855 to 0.984), and 0.934 for observer 4 (95% CI 0.790 to 0.984). The mean time required to examine the samples was two minutes (sd 2; 1 to 5).

Conclusion

The method presented here was shown to be sufficiently precise for many settings and is a cost-effective and quick method of determining the volumetric wear of explanted acetabular components. However, the measurement of wear for scientific purposes will probably continue to involve more accurate and dedicated laboratory equipment.

Cite this article: L. Krakow, A. Klockow, E. Roehner, S. Brodt, H. Eijer, J. Bossert, G. Matziolis. A simple method of measuring the wear of explanted acetabular component inserts. Bone Joint Res 2017;6:530–534. DOI: 10.1302/2046-3758.69.BJR-2016-0249.R1

[Use of dual mobility cups for revision hip arthroplasty]

The dual mobility cup (DMC) is an increasingly important tool not only in primary but also in revision total hip arthroplasty to prevent dislocation and eventually reduce postoperative complication rates. Various studies have shown survival rates with DMCs of up to 100% with an average dislocation rate of less than 1.5% after primary hip arthroplasty and a follow-up of 10 years. In revision surgery, survival rates of up to 99% were reported with dislocation rates between 0 and 10% after an average of 5 years after implantation. This article is intended to provide an overview of the principle and function of DMCs. Furthermore, indications as well as complications are presented.

Cementless Total Hip Arthroplasty in Primary Myelofibrosis - a Case Report

There is a great deal of data available, in part contradictory, on the best fixation technique to use for total hip arthroplasty (THA) in hip osteoarthritis. Both the cementless and the cemented versions offer excellent long-term outcomes - if the respective technique is applied correctly. However, as far as we know, no recommendation has been made regarding cemented vs. cementless THA in primary myelofibrosis. The case described here concerns a very active 76-year-old patient with primary myelofibrosis. This is a rare hematological disease. It develops from clonal hematopoiesis with impaired blood formation and progressive bone marrow fibrosis. An MRI scan of the patients pelvis showed a marked spotted change over all of the imaged bone. Ultimately, in preoperative planning we decided in favor of a proven cementless implant (Allofit Alloclassic cup and the CLS Spotorno stem from Zimmer). Complication-free osseous integration of the cementless implants was observed. Histologic analysis of the bone showed a focally sclerotically altered bone structure. Neither osteoporosis nor osteopenia were found. In our opinion, taking into account all other indication criteria, there is no reason not to perform a cementless THA implantation in the presence of primary myelofibrosis. Key words: hip, primary myelofibrosis, cementless, THA, total hip replacement.

[Functional Comparison of the Outcome after Midvastus and Medial Parapatellar Surgical Approach in Total Knee Arthroplasty]

There are various approaches for total knee arthroplasty (TKA). On the basis of an analysis of the clinical results, it has been demonstrated that the midvastus approach (MV) is advantageous in the early postoperative period compared to the medial parapatellar surgical approach (MPP). The aim of this investigation was therefore to investigate whether the clinical advantage of MV is reflected in the functional outcome. This single blinded, prospective, randomised study was based on a power analysis. Selected randomised patients (MPP = 10, MV = 11) were examined using an instrumental gait analysis system (VICON) preoperatively, and 5 weeks (5 W) and 6 months (6 M) after implantation. The results were compared to a healthy control group (CG = 53). Besides clinical parameters, the primary objective of this study was to measure objective gait parameters; the secondary objective was to record self-assessment (Knee Society score, WOMAC). In both treatment groups, the measurements improved during the investigation period, although most parameters did not reach the CG levels. MV gave better values for the kinetic parameters sagittal knee moment (5 W) and knee power (5 W, 6 M), as well as self-assessment (WOMAC, 6 M). Other clinical parameters were similar in the two groups. In summary, in the early postoperative period, MV led to advantages in function and in subjective behaviour in daily life. From the biomechanical point of view, the MV approach is preferable.

[Arthritis of the Medial Knee Joint Compartment]

23 % of all persons older than 65 years suffer from osteoarthritis of the medial compartment of the knee joint, a very common situation in orthopaedic practice 1. As a result of the demographic trend the number of patients is expected to increase in the future. Based on specific joint biomechanics and kinematics the medial knee joint compartment is more frequently affected than the lateral. Only an understanding of the functional anatomy and underlying pathology allows a critical evaluation of different available conservative and operative treatment options. This article gives an overview of diagnostic and therapeutic strategies of osteoarthritis of the medial knee joint. Frequently performed surgeries, e.g. high tibial osteotomy (HTO), unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) will be presented in a comparative manner. The actual scientific evidence will be given with the goal of an evidence based therapy that is adopted to stage and pathology of osteoarthritis of the medial compartment of the knee joint.

[How to determine the rotation of the femoral component]

The different landmarks for determination of the rotation of the femoral component are shown and specific pros and cons are discussed. The videos demonstrate how to identify them intraoperatively.

[Total knee arthroplasty in 2014 : Results, expectations, and complications]

BACKGROUND

Aseptic loosening seems to have become a minor problem in total knee arthroplasty. In contrast to that, new challenges are defined by changing patients' expectations. Beside reduction of pain and improving mobility, modern implants should not be noticed as such and should not limit sports activities.

OBJECTIVES

In this paper, a summary of the development and the current situation of total knee arthroplasty (e.g., implantation numbers, hospitality, operation time, and infection rates) are provided. The data are compared in an international context. In addition, current trends and developments from recent years are shown and rated according to the literature.

MATERIALS AND METHODS

The paper is based on a literature search (PubMed) and analyses of published official statistical data and expert recommendations.

RESULTS

Implantation numbers have been declining gradually in Germany since 2009. In 2013, 127,077 total knee arthroplasties were implanted. In contrast, the number of revision operations has increased gradually during the last decade. In addition, hospital stay and operation time have declined.

CONCLUSION

The development of implants, instruments, and operation techniques results from changing patients' expectations. All innovations must be compared against the results of well-proven techniques. The arthroplasty register may be an instrument to evaluate the results of new techniques and implants in a broad clinical application in terms of survival.

Arthroscopic-Assisted Intraosseous Balloon-Assisted Repositioning of a Tibial Plateau Fracture: A Case Report

This is the first description of an arthroscopic-assisted intraosseous balloon-assisted repositioning and defect filling of a tibial plateau fracture. The bone defect was filled with calcium phosphate cement in a liquid/paste form. The described technique was therefore introduced in order to allow an arthroscopic control of reposition and intra-articular cement escape during defect filling. X-rays showed an exact reposition without cement escape and the clinical outcome was satisfactory.

[The post-traumatic arthritis - a challenge?]

Total knee replacement in patients with post-traumatic arthritis is not fundamentally different from total knee replacement in patients with primary arthritis. Because of a 10-times higher infection rate, ordinary surgical planning should be implemented by the best possible exclusion of site infection based on actual information. Extra-articular deformities have to be preoperatively identified and individually treated with either an incomplete or a complete intra-articular correction or a single or double correction osteotomy. The commonly found combination of a contracted knee joint and an insufficient ligament balancing can mask instabilities of the knee joint. Consequently the definitive grade of a constrained knee prosthesis can only be determined intraoperatively. Existing osseous defects can be addressed with autologous bone grafts left from the total knee arthroplasty. Depending on the osseous defective site and the grade of constraints, prosthesis stems may be necessary but so far no clear recommendation can be given for either a cemented or a cementless fixation of the stem. The approach to the knee joint should be guided according to existing scars in order to prevent wound healing disorders. Even given optimal surgical planning and an optimum procedure of total knee arthroplasty postoperative results of post-traumatic arthritis are significantly inferior to results of primary arthritis. Therefore it is important to induce the commonly younger patients to form realistic expectations.

Invasive electromagnetic field treatment in osteonecrosis of the femoral head: a prospective cohort study

Introduction :

The purpose of this prospective cohort study was to compare the surgical treatment of non-ONFH in adulthood by curettage and bone grafting with treatment by curettage and bone grafting in combination with invasive electromagnetic field treatment using Magnetodyn^®. This was assessed by examining whether electromagnetic field treatment has a positive additive effect on the clinical parameters modified Harris Hip Score according to Haddad, Cook and Brinker, Merle d'Aubigné hip score and visual analogue scale, and on the subsequent need for treatment by total hip arthroplasty.

Materials and Methodology :

The prospective, non-randomised study included 35 patients with unilateral or bilateral osteonecrosis of the femoral head. These were divided into two groups according to the surgical treatment regime and assessed over a 12-month follow-up period. The study group (Group 1) comprised 19 patients (14 men and 5 women) with a total of 22 non-ONFH, who underwent minimally invasive curettage, bone grafting and electromagnetic field treatment (Magnetodyn^®) by implantation of a bipolar induction screw. The control group (Group 2) comprised 16 patients (12 men and 4 women) with a total of 18 non-ONFH, who underwent minimally invasive curettage and bone grafting without Magnetodyn^® therapy. At the initial pre-operative examination and the 6 and 12-month follow-up, all patients were assessed by clinical examination and radiological monitoring, and by bilateral hip MRI. The clinical evaluation was based on the modified Harris Hip Score according to Haddad, Cook and Brinker, the Merle d`Aubigné hip score and the visual analogue scale (VAS).

Results :

At the time of follow-up, total hip arthroplasty (THA) had been performed in four patients in Group 1 (18%). In Group 2, four patients (22%) had received a THA (n.s.). Both procedures led to an improvement in the clinical scores (Harris Hip Score, Merle d`Aubigné score and VAS), although no significant difference was observed.

Conclusion :

The authors conclude that electromagnetic field treatment with Magnetodyn^®, using the special signal protocol applied here, as an adjunct to curettage and autologous bone grafting to treat non-ONFH, does not produce better clinical results and does not offer better prophylaxis for the avoidance of total hip arthroplasty over all ARCO stages.

[Early results of gender-specific posterior stabilized total knee arthroplasty without patella resurfacing]

INTRODUCTION

To address anatomical gender differences in total knee arthroplasty (TKA) specific total knee prostheses have been developed for women. Potential benefits of these modified prostheses are currently under debate. The present study investigated whether the modified design features bring benefits compared to uni-sex TKA.

METHODS

A total of 80 prospectively blinded and randomized patients underwent implantation of unilateral TKAs with NexGen LPS Gender Solutions (Zimmer, Warsaw, USA, group gender-specific GS prosthesis, n = 40) or NexGen LPS Flex (Zimmer, Warsaw, USA, control group standard prosthesis ST, n = 40) The follow-up was carried out 10 days and 6 weeks postoperatively. Clinical data and the subjective assessment of quality of life were evaluated using the Knee Society Clinical Rating System (KSS), the short form 36-item health survey (SF-36) and the Western Ontario and McMaster Universities OA Index (WOMAC).

RESULTS

The two groups showed equal values in KSS, SF-36 and WOMAC preoperatively and ten days postoperatively the GS group reached an average KSS knee score of 62.6 ± 16.1 points (ST group 56.9 ± 14.7, p = 0.184) and a functional score of 28.5 ± 12.1 (ST group 24.3 ± 15.3, p = 0.082). In the overall score the GS group reached 91.1 ± 24.1 points (ST group 81.0 ± 27.1, p = 0.104). The GS group reached a knee score of 85.5 ± 14.4 points (ST group 77.8 ± 16.8, p = 0.03) and a functional score of 68.1 ± 20.7 points (ST group 62.3 ± 18.5, p = 0.185) 6 weeks postoperatively. In the overall score the GS group reached 153.7 ± 30.7 points (ST group 139.6 ± 32.4, p = 0.048). The analysis of SF-36 and WOMAC showed no significant differences at all time points. No evidence of loosening or migration was observed in both groups.

CONCLUSIONS

Based on the data presented, gender-specific TKA type NexGen LPS Gender Solutions has advantages in terms of early functional outcome. This result is not reflected in the patient satisfaction and is not considered to be clinically relevant.

[Tibiocalcaneal arthrodesis with retrograde nails. Description of a hindfoot procedure after massive talus destruction]

Following loss of the talus, tibiocalcaneal fusion is often the only available means of obtaining weight-bearing ability in the lower limb. Length discrepancy may be managed with an allograft. This casuistic describes 6 patients with tibiocalcaneal fusion (mean age 64 years) who had received a structural femoral head allograft fusion for failed total ankle arthroplasty (3 cases), Charcot arthropathy (2 cases) and osteomyelitis (1 case). The mean follow-up was 33 months and all limbs could be salvaged. There were two cases of non-union (one with infection). The mean AOFAS score was 51 and the mean Mazur score was 37. In the SF-36 the mean PCS was 34.4 and the mean MCS was 48.4. It was shown that in the hindfoot, as at other sites, allografts may be used for the filling of major bone defects; however, the patient function will still be massively impaired. Therefore, the procedure should be confined to cases where less complex and less invasive techniques are unlikely to be of benefit.

[Revised consensus classification. Histopathological classification of diseases associated with joint endoprostheses]

The revised classification of the periprosthetic membrane (synovial-like interface membrane SLIM) encompasses all pathological alterations which can occur as a result of endoprosthetic replacement of major joints and lead to a reduction in durability of prostheses. This also includes the established consensus classification of SLIM by which aseptic and septic prosthetic loosening can be subdivided into four histological types and histopathological criteria for additional pathologies: endoprosthesis-associated arthrofibrosis, immunological/allergic alterations and osseous pathologies. This revision represents the foundation for the histopathological diagnostics of the total spectrum of diseases associated with joint prostheses, is a suitable basis for a standardized diagnostic procedure and etiological clarification of endoprosthesis failure and also as a data standard for endprosthesis registers, in particular for registers based on routine data (e.g. German endoprosthesis register).

[The bicompartmental knee joint prosthesis Journey Deuce: failure analysis and optimization strategies]

BACKGROUND

The Journey Deuce bicompartmental knee system is intended for patients with medial and patellofemoral arthritis of the knee and is aimed at diversifying the treatment options for knee arthritis. The prosthesis consists of a combined femoral shield with a medial condylar resurfacing component and a fixed bearing unicondylar tibial knee prosthesis. The advantages of the Journey Deuce system compared to total knee arthroplasty (TKA) are the bone sparing and cruciate retaining implantation. Outcome studies and investigation with respect to success and revision rates are rare. Thus the aim of this study was to investigate the early functional outcome as well as the revision and complication rates in patients with a Journey Deuce prosthesis within the first 2 years.

METHODS

In this study 43 patients (25 female/18 male, average age 62.4 ± 8 years and mean body mass index27.3 ± 4.5 kg/m(2)) underwent bicompartmental knee arthroplasty using the Journey Deuce prosthesis between March 2008 and March 2009. Inclusion criteria were clinically and radiographically confirmed patellofemoral arthritis, ligament stability and flexion > 90°. Exclusion criteria were extension deficits > 5°, axis deviation > 10° and patellofemoral malalignment. Patients were followed up for 6, 12 and 24 months postoperatively. Follow-up consisted of clinical and radiographical examination as well as a survey of the Knee Society score (KSS), a pain score (visual analog scale VAS, range 0-10) and a satisfaction score.

RESULTS

Of the patients 35 (82%) patients reached the 2-year follow-up and of these 35 patients 26 (75%) had a good to very good satisfaction, a mean KSS of 93 (range 65-100) and a minimal pain score of 1.2 (range 0-4). After 12 months all patients had a knee flexion of more than 90° (mean 116°, range 95°-140°). Loosening was not detected but 8 (18%) patients had to undergo revision within the first year due to persistent knee pain and instability.

CONCLUSIONS

Under clear indications and exact anatomical positioning the Journey Deuce prosthesis enables a good functional outcome; however, a high revision rate occurred in this study caused by technical complexity and insufficient variety of implant sizes which led to malalignment and instability. Additional positional guidance and a higher variability in implant sizes are required to enable an adequate treatment with anatomically correct positioning. The Journey Deuce prosthesis would then be a reasonable diversification of the endoprosthesis spectrum in knee arthroplasty and would allow a more individual and selective treatment of patients with knee arthritis.

[More muscle mass in men: explanatory model for superior outcome after total hip arthroplasty]

BACKGROUND

Men show better functional results after total hip arthroplasty (THA). The aim of this study was a patient-specific analysis of the hip joint muscles in comparison to the joint geometry.

METHODS

In this study 93 computed tomography (CT) scans of the pelvis (45 men, 48 women) were analyzed to determine hip joint geometry and the volume of the gluteus medius (GMV), gluteus maximus (GXV) and tensor fasciae latae (TFL) muscles. The abduction muscle volumes were analyzed with respect to patient-specific adduction moments.

RESULTS

The absolute total volume of the hip muscular system (TMV) was larger in men than in women (1913 ccm vs. 1479 ccm; p <0.0001). Men exhibited a more progressive increase of muscle volume as the adduction moment increases.

CONCLUSIONS

Men have a greater abduction muscle mass in order to balance adduction moments occurring in the hip joint and therefore have more muscle mass to compensate the inevitable intraoperative muscle damage during THA. This argument supports the extraordinary importance of muscle sparing surgical techniques in women.

Wound drainage in primary knee arthroplasty--a prospective randomized study

PURPOUSE OF THE STUDY: Wound drainage in surgical interventions has a long tradition. Regarding the primary TKA there are no valid data concerning the ideal point of time for removal. The objective of this prospective randomized study was to investigate which drainage procedure should be given preference with regard to wound healing, blood loss, development of intraarticular hematomas and early postoperative function.

MATERIAL AND METHODS

We documented the ROM, the knee circumference at the upper patellar pole preoperatively and on days 2, 4 and 6 postoperatively. The blood volume and loss was calculated. As surrogate parameter for wound healing we counted the amount of days until no residual secretion was observed via the wound/drainage site.

RESULTS

The results of our investigation do not show any significant difference with regard to the mentioned parameters.

CONCLUSIONS

In our investigation, we were unable to find any significant advantage of intraarticular drainage for 48 hours over 24 hours after primary total knee arthroplasty. After uncomplicated total knee arthroplasty we recommend removing drainage after 24 hours.

[Extension first technique for TKA implantation]

OBJECTIVE

Surgical technique in total knee arthroplasty (TKA) to combine the femur first and tibia first techniques in order to reduce surgical mistakes regarding rotation and alignment.

INDICATIONS

Symptomatic arthritis of the knee.

CONTRAINDICATIONS

General contraindications for TKA.

SURGICAL TECHNIQUE

Osseous preparation starting with a distal femur cut. Then the proximal tibia cut is accomplished and the knee is balanced in extension after checking for correct alignment. Bone-referenced positioning of the femoral cutting block for further preparation of the femur. Finally, the rotation of the femur is checked in 90° of flexion by means of ligament tension. If required, the rotation is checked and the flexion gap balanced, respectively.

POSTOPERATIVE MANAGEMENT

Mobilization with weight bearing and range of motion as tolerated.

RESULTS

In a prospective study, 267 knees (160 women, 107 men, average age of 69.3 [46-89] years) were followed up preoperatively and after 6 weeks. The clinical results were based on the American Knee Society score. The scores were 48.9 (32-68) preoperatively and 86.5 (75-100) at follow-up. Radiologically 92.1% of the knees showed a malposition <3°.

Periprosthetic fractures around the knee: update on therapeutic algorithms for internal fixation and revision arthroplasty

Effective treatment of periprosthetic fractures following TKA continues to represent a surgical challenge. The incidence and frequency of these complicated type of fractures is expected to increase as the number of TKA as well as the activity level of these patients steadily rises. A careful and correct analysis of the fracture pattern, its classification, the quality of the existing bone stock and the fixation / loosening of the underlying prosthetic system has to precede decision making for successful conservative or surgical treatment. Therefore, improved diagnostic radiographic imaging of fracture patterns and reliable assessment of prosthesis loosening progressive development of new implant methods and refinement of soft tissue preserving surgical techniques will hold the key for regaining the functional level prior to the fracture.

[TKA revision of semiconstraint components using the 3-step technique]

OBJECTIVE

The surgical goal is to achieve a pain free and stable knee joint after revision total knee arthroplasty in three steps. An important component of the technique is the reproducible restoration of the joint line.

INDICATIONS

Revision total knee arthroplasty.

CONTRAINDICATIONS

Complete bone loss at the knee joint (epicondyles and tibia plateau), persistent joint infection, loss of the extension apparatus, and neurological disease with progressive ligament instability.

SURGICAL TECHNIQUE

Implantation of revision components is performed in three steps. The first step is the positioning of the tibia component at the correct height and rotation. As the position of the tibial articular surface is independent of the knee position, the tibia serves as a reference both in extension and in flexion. The second step consists of balancing the knee joint in flexion and, thereby, definition of the flexion gap and the rotation of the femoral component. In the third step, the reconstruction and balancing of the knee joint in extension is performed.

POSTOPERATIVE MANAGEMENT

Mobilization with weight bearing and range of motion as tolerated depending on osseous and soft tissue condition at surgery. The surgical technique does not influence the further treatment.

RESULTS

In a prospective study, 168 consecutive knee revisions operated by the first author were examined clinically and radiologically preoperatively and at a mean follow-up of 38 months (range 22-61 months). There were 96 knees from women and 72 were from men with an average age of 74.6 years (range 51-92 years). Clinical results were based on the American Knee Society score. The score showed 47.6 (range 32-63) preoperatively and 81.5 (range 62-95) at follow-up. Radiologically, 92.7% of the knees showed a malposition <3°. The joint line was correctly reconstructed in 86.3% based on the preoperative plan; 89% of the patella showed correct tracking in the patella tangential view.

Induced apoptosis of chondrocytes by Porphyromonas gingivalis as a possible pathway for cartilage loss in rheumatoid arthritis

The role of bacterial infections in the pathogenesis of rheumatoid arthritis (RA) has gained increasing interest. Patients with RA often exhibit periodontal disease, which is associated with pathogens like Porphyromonas gingivalis. The present study examines the direct effects of P. gingivalis on apoptosis of human chondrocytes (a feature of inflammatory joint diseases) as one can assume an interrelation of pathogenesis of RA and P. gingivalis infections. Primary chondrocytes were infected with P. gingivalis. Early apoptotic and dead cell analysis was performed using Annexin-V, 7AAD, and propidium iodide and examined by flow cytometry and fluorescence microscopy. Caspase activation and DNA fragmentation were determined by western blot analysis and TUNEL reaction. Flow cytometry and fluorescence microscopy demonstrated an increase of Annexin-V-positive early apoptotic chondrocytes after infection. Western blot showed upregulation of activated caspase-3 expression, and TUNEL reaction revealed considerable DNA fragmentation following infection. The data show that P. gingivalis promotes early and later stages of apoptosis of primary human chondrocytes, which might contribute to the joint damage seen in the pathogenesis of RA.

Effects of celecoxib on the expression of osteoprotegerin, energy metabolism and cell viability in cultured human osteoblastic cells

BACKGROUND AND OBJECTIVE

The selective COX-2 inhibitor celecoxib is widely used to treat pain and inflammation in rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. The drug has well-known important effects on immune cells but its direct and/or indirect influence on osteoblasts has not yet been explored in detail. This study aimed to investigate the dose-dependent effects of celecoxib on cell viability, energy metabolism and bone remodeling processes in cultured human osteoblastic cells.

METHODS

Primary human osteoblasts and MG-63 cells were incubated with celecoxib (2, 10, 50microM). Cell viability and apoptosis were determined by trypan blue, 7AAD and Annexin-V staining. Effects on cellular oxygen consumption were measured amperometrically using a Clark electrode. mRNA expression of GLUT-1 and OPG was determined by RT-PCR; OPG protein secretion by ELISA and HIF-1alpha protein expression by immunoblotting.

RESULTS

While celecoxib at a concentration of 2 and 10microM showed only marginal effects, a suprapharmacological concentration of 50microM influenced viability and energy metabolism, as well as OPG expression and secretion of osteoblastic cells. Cell viability was significantly reduced by celecoxib treatment. Celecoxib at 50microM stimulated oxygen consumption significantly. Corresponding experiments with the protonophore FCCP suggest that this effect is due to mitochondrial uncoupling. After 24h, GLUT-1 mRNA expression was significantly increased. HIF-1alpha protein was not expressed under any of our experimental conditions. We also showed that celecoxib at 50microM significantly inhibits OPG protein secretion leading to a compensative increase of mRNA expression.

CONCLUSION

Pronounced effects of celecoxib on cell viability (reduction), oxygen consumption (stimulation), GLUT-1 mRNA expression (stimulation) and OPG protein secretion (inhibition) in osteoblastic cells were observed only at 50microM-a concentration not reached by therapeutic doses giving plasma concentrations less than 10microM. On the contrary, celecoxib at 2 and 10microM showed only marginal effects, suggesting that celecoxib administration is probably safe with respect to bone metabolism in cases requiring potent treatment of pain and inflammation. However, higher intracellular concentrations, which might occur through accumulation, necessitate investigations with high concentrations.

Effects of Porphyromonas gingivalis on cell cycle progression and apoptosis of primary human chondrocytes

BACKGROUND

It has been suggested that bacterial infections have a role in the pathogenesis of rheumatoid arthritis (RA). P gingivalis, a Gram-negative, anaerobic rod, is one of the major pathogens associated with periodontal disease.

OBJECTIVE

To examine P gingivalis infection and its effects on cell cycle progression and apoptosis of human articular chondrocytes.

METHODS

Primary human chondrocytes cultured in monolayers were challenged with P gingivalis. Infection and invasion of P gingivalis into chondrocytes was analysed by scanning electron microscopy, double immunofluorescence and by antibiotic protection and invasion assay. Cell cycle progression of infected chondrocytes was evaluated by flow cytometry. Also, cell apoptosis was visualised by terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) of DNA strand breaks and by western blot analysis.

RESULTS

Data showed that P gingivalis could adhere and infect primary human chondrocytes. After chondrocyte infection, intracellular localisation of P gingivalis was noted. Flow cytometry analyses demonstrated affected cell cycle progression, with an increase of the G(1) phase and a significant decrease of the G(2) phase after infection. In addition, increased apoptosis of P gingivalis-infected chondrocytes was visualised by TUNEL assay and by upregulation of caspase-3 protein expression.

CONCLUSION

These data demonstrate that P gingivalis infects primary human chondrocytes and affects cellular responses, which might contribute to the tissue damage seen in the pathogenesis of rheumatoid arthritis.

[Promotion of bone healing through clinical application of autologous periosteum derived stem cells in a case of atrophic non-union]

This case report describes the application of periosteum-derived mesenchymal stem cells in a patient with atrophic non-union of the distal femur after correction osteotomy. While biomechanical treatment devices for various bone defects are available in abundance, biological promoters for clinical application in situations of critical bone healing are still scarce. We showed radiographically that cultivated autologous periosteal bone precursor cells on a three-dimensional matrix can promote bone healing in a defect where numerous established methods had failed to lead to consolidation. To the best of our knowledge, this is the first clinical application of in-vitro cultivated autologous periosteum-derived cells for the healing of a large bone defect in humans.

[Musculoskeletal biomechanics of the knee joint. Principles of preoperative planning for osteotomy and joint replacement]

The long-term clinical outcome of surgical interventions at the knee is dependent upon the quality of the restoration of normal function, together with moderate musculoskeletal loading conditions. In order to achieve this, it is essential to consider biomechanical knowledge during the planning and execution of the procedures. Until now, such knowledge has only been available in books and journal manuscripts and is merely considered during preoperative planning. Its transfer into the specific intraoperative situation is, however, primarily dependent upon the surgeon's skills and understanding. Mathematical models hold the potential to provide the surgeon with detailed, patient-specific information on the in vivo forces, as well as their spatial and temporal distribution. Their application in clinical routine, however, requires a comprehensive validation. Based on a model validated against patient data, it has been shown that - mainly as a result of the action of the muscles - both the tibiofemoral as well as the patellofemoral joints experience substantial mechanical loads even during normal activities of daily living. The calculations further indicate that malalignment at the knee in the frontal plane of more than approximately 4 degrees results in considerably increased forces across the tibiofemoral joint. The actual change in force to a given degree of malalignment might, however, vary greatly between subjects. In order to additionally determine the distribution of the forces in more detail, a sufficiently accurate model of knee joint kinematics is required. In combination with MR-based in vivo imaging techniques, new mathematical models offer the possibility to capture the individual characteristics of knee kinematics and might additionally allow the effect of muscle activity on joint kinematics to be considered. By implementing these technologies in preoperative planning and navigation systems, up-to-date biomechanical knowledge can be made available at the surgeons' fingertips. We propose that optimizing the biomechanical conditions through using these approaches will allow the long-term function of the replaced joint to be significantly enhanced.

[Implant with a mobile or a fixed bearing in unicompartmental knee joint replacemen]

Although the goal of anatomical and functional joint reconstruction in unicompartmental knee replacement is well defined, no uniform implant design has become established. In particular, the differential indications for implantation of an implant with a mobile or a fixed bearing are still not clear. The long-term results of mobile and with fixed bearings are comparable, but there are significant differences in resulting knee joint kinematics, tribological properties and implant-associated complications. In unicompartmental knee replacement mobile bearings restore the physiological joint kinematics better than fixed implants, although the differences to total knee arthroplasty seem minor. The decoupling of mobile bearings from the tibia implant allows a high level of congruence with the femoral implant, resulting in larger contact areas than with fixed bearings. This fact in combination with the more physiological joint kinematics leads to less wear and a lower incidence of osteolyses with mobile bearings. Disadvantages of mobile bearings are the higher complication and early revision rates resulting from bearing dislocation and impingement syndromes caused by suboptimal implantation technique or instability. Especially in cases with ligamentous pathology fixed bearings involve a lower complication rate. It seems their use can also be beneficial in patients with a low level of activity, as problems related to wear are of minor importance for this subgroup. The data currently available allow differentiations between various indications for implants with mobile or fixed bearings, so that the implants can be matched to the patient and the joint pathology in unicompartmental knee joint replacement.

[Musculoskeletal load analysis. A biomechanical explanation for clinical results--and more?]

Mechanical loading of the lower extremities due to muscle and joint contact forces plays an important role in orthopaedic and trauma surgery. Detailed, patient specific information on the in vivo forces and their distribution is, however, currently not readily available to the surgeon in clinical routine. The goal of this study was to elucidate the relationship between the position of the cup and the musculoskeletal loading conditions at the hip using validated analyses, and further, to evaluate the predictions of the biomechanical conditions against the results of a clinical study. The results indicate that restoring the anatomical hip centre to its anatomical mediolateral position could help to reduce joint loads and add to the longevity of the reconstruction. The routine use of validated analyses of musculoskeletal loading conditions, such as in the presented example using standardised pre-operative planning and sound intra-operative decision support systems, could contribute to securing a high standard in patient treatment.

[The reconstruction of extended acetabular bone defects in revision hip arthroplasty--risk factors for migration and loosening using the pedestal cup]

AIM

For the reconstruction of extended acetabular bone defects in revision hip arthroplasty different implants and techniques are available.However, in cases with a broad operative range of new implants, specific indications must be determined. The aim of this study is to determine the risk factors for migration and loosening associated with implantation of the pedestal cup.

METHOD

In a retrospective study the first 50 implantations of the pedestal cup in our hospital for high-grade acetabular defects (Paprosky classification II and III) were examined after a medium period of 26 months. Differences between radiologically loosened and osteal integrated implants in consideration of the preoperative osseous situation(defect size and morphology, bone density)as well as the implant positioning were determined as risk factors of an implant failure.

RESULTS

Three (6%) intraoperative implant-associated complications occurred, which were in the phase of the initial learning curve. In the early postoperative period 10 hip dislocations (20%)occurred. Two septic loosenings (4%) and 6 aseptic loosenings (12%) were observed. In 7 further cases a significant migration of the implant was assessed in the first months after surgery, a solid osteal integration did not appear. As risk factors for an implant loosening were determined:a missing reconstruction of the defect behind the pedestal cup with allogenous bone graft(p = 0.002), a lateralisation of the rotation centre(p = 0.023), the absence of the craniolateral wall (p = 0.002) and the presence of osteoporosis(p = 0.026).

CONCLUSION

The pedestal cup is an implant that is well usable in many high-grade acetabular defect situations with good mid-term results; however,contraindications do exist. In cases with a significant osteoporosis, a missing sclerosis of the cranial acetabulum as well as extended damage of the lateral ilium and its absence, respectively, alternative procedures should be considered.

Rekonstruktion des Streckapparats mittels freiem, allogenem, gefriergetrocknetem Patellatransplantat

Allograft reconstruction of a deficient extensor mechanism is sufficient using an allogenic, freeze-dried patellar graft sterilized with peracetic acid. The reduced risk of infection is an advantage over fresh-frozen grafts.

[Reduction of arthrosis associated knee pain through a single intra-articular injection of synthetic hyaluronic acid]

AIM

Conventional hyaluronic acids need three to five injections for therapeutic success, whereas Durolane), a synthetic hyaluronic acid, needs only a single injection. Clinical outcome using Durolane should be compared with the results of studies using hyaluronic acids or glucocorticoids.

METHOD

Fifty patients with primary gonarthrosis stages I-III (Kellgren Score) were investigated for knee function, pain intensity, and quality of life. The knee and osteoarthritis outcome score (KOOS), visual analogue scale (VAS), and European quality of live score (EQ-5D), as well as motion of the knee were measured. Patients were investigated before, and 2, and 24 weeks after injection.

RESULTS

Two weeks after injection, the subjective function of knee and quality of life had increased significantly. In the following 22 weeks, all parameters increased significantly (quality of life and activity +19%; range of motion active 109 vs. 115 degrees ; pain, 55 vs. 41 mm (VAS); all p<0.01).

CONCLUSION

We conclude that a single injection of Durolane can reduce arthrosis associated knee pain sufficiently. Our data are comparable with those published in clinical studies using other hyaluronic acids. The effects of Durolane are delayed but more sustained compared than those found for glucocorticoids. Because of the single injection, we see an advantage in using Durolane compared to other conventional hyaluronic acids and glucocorticoids.

Computer tomographically determined design parameters for optimized fit of an acetabular reconstruction cage

PURPOSE OF THE STUDY

Reinforcement rings are widely used for treatment of large acetabular defects but significant migration due to a lack of implant integration into the bone is a common problem. Although insufficient congruence between implant and acetabular bone has been identified main factor in early implant loosening, there are no reconstruction ring design parameters based upon anatomical data of the pelvis available.

MATERIAL

In this study such parameters were calculated on the basis of standardized computer tomograms of the hip region of 10 male and 10 female patients (40 data sets).

METHODS

The center of rotation, the acetabular entrance plane and the geometry of a simulated cranial and caudal flange of a reconstruction ring were determined. The flanges geometry was defined by the angles between the flanges and the entrance plane, the angle between the flange projections onto the entrance plane, the torsion and the width of each flange depending on the distance to the center of rotation, and the flanges torsion and width at their origin at the acetabular circumference.

RESULTS

An optimal alignment between reconstruction ring and the periacetabular bone could be achieved with a medial angulation of 19.9 degrees +/- 19.4 degrees of the cranial and 14.7 degrees +/- 7.1 degrees of the caudal flange against the entrance plane. The angle between the flanges projections onto the entrance plane was calculated to be 162.2 degrees +/- 6.4 degrees . At its origin from the acetabular circumference the cranial flange is twisted 28.5 degrees , the caudal flange -0.8 degrees against the entrance plane. The maximal flanges widths were calculated to 21-54 mm for the cranial and 22-25 mm for the caudal flange depending on the distance from the acetabular circumference.

DISCUSSION & CONCLUSION

The given design parameters may result in optimized implants respecting the pelvic anatomy and possibly providing improved fixation.

[Accuracy of determination of the hip centre in navigated total knee arthroplasty]

AIM

In navigated knee arthroplasty the hip centre is determined by rotary motion of the femur (pivoting). The accuracy of this functional hip centre determination in vivo is unclear. In the following paper the accuracy of pivoting in the determination of the hip centre was examined.

METHODS

Navigated (TC-PLUS, Solution, PLUS Orthopedics) total knee arthroplasty (PI Galileo, PLUS Orthopedics) was performed on 25 patients with primary arthritis of the knee joint. The position of the femoral component and the hip centre were postoperatively determined by computer tomography. Through comparison with the intraoperatively documented data, the deviation of the pivoted from the true hip centre in the frontal and sagittal planes was calculated. The degree of arthritis of the hip was determined on plain radiographs according to Kellgren.

RESULTS

The mean deviation was determined to 1.0 +/- 0.7 degrees in the frontal plane and 2.5 +/- 1.6 degrees in the sagittal plane (p = 0.002). This corresponds to a mean overall deviation of 20 +/- 10 mm. The data were continuously, non-parametrically distributed without any outliers. A great range of motion (ROM) in the frontal as well as sagittal planes during pivoting resulted in a less accurate determination of the hip centre. There was no correlation to the degree of arthritis of the hip.

CONCLUSION

The results indicate a recommendable ROM during pivoting for maximal accuracy of hip centre determination of 20 to 30 degrees in the sagittal plane and 30 to 40 degrees in the frontal plane. Arthritis of the hip is not a contraindication for functional determination of the hip centre.

Varianz der Epikondylenerfassung bei der navigierten Knieendoprothesenimplantation

BACKGROUND

The aims of this study were the quantification of the accuracy of registration of the epicondylar axis (EA) in navigated total knee arthroplasty (TKA) and the identification of presumed factors influencing this accuracy.

METHODS

A total of 32 navigated TKAs were performed and the surgical EA registered. Postoperatively, the difference from the surgical EA determined by computed tomography was calculated. Presumed factors influencing the accuracy were sex, preoperative malalignment, stability and range of motion, operated side, body mass index, and component size.

RESULTS

The absolute error was calculated to be 1.4+/-1.3 degrees . Alignment according to the intraoperatively defined axes would have resulted in three outliers (>3 degrees malalignment). The operated side was the only factor showing a significant effect on the accuracy. The absolute error in left knee joints was calculated to be 0.9+/-0.7 degrees (max. 2.4 degrees ) and in right knee joints to be 2.0+/-1.5 degrees (max. 5 degrees, p=0.021).

CONCLUSIONS

The surgeon stood on the patient's right side in every case, so that right knee joints were operated from the lateral and left ones from the medial side. A medial position of the surgeon to the knee joint during registration of EA is recommended because it results in a higher accuracy than a lateral position.

Effects of dexamethasone and celecoxib on calcium homeostasis and expression of cyclooxygenase-2 mRNA in MG-63 human osteosarcoma cells

OBJECTIVE

Glucocorticoids and selective COX-2 inhibitors are potent anti-inflammatory agents. They are also suggested to influence bone physiology and remodeling. Here we searched for effects of dexamethasone and celecoxib on crucial parameters of bone physiology that could be therapeutically relevant.

METHODS

The human osteosarcoma cell line MG-63 was used to measure effects of these drugs on (i) intracellular calcium concentration ([Ca2+]i) using a microfluorometric technique, (ii) alkaline phosphatase and osteocalcin levels (EIA) and (iii) the expression of cox-2 mRNA (quantitative real time PCR). Measurements were performed in Vitamine D-incubated quiescent cells and in cells stimulated with TNF-alpha and IL-1beta.

RESULTS

We found the cytokine-stimulation to increase [Ca2+]i which was prevented by dexamethasone already after 30 min and still after 48 h. Dexamethasone was without any effect on [Ca2+]i in quiescent cells. Celecoxib had no measurable short-term or long-term effects neither in quiescent nor in stimulated cells. Vitamin D stimulated the expression of cox-2 mRNA which was further enhanced by TNF-alpha/IL-1beta. Dexamethasone did not have any measurable effects on COX-2 expression after 30 min, but a pronounced inhibition was seen after 48 h. In contrast, celecoxib had no effect on COX-2 expression. Neither of the drugs had any effect on the secretion of alkaline phosphatase and osteocalcin.

CONCLUSION

We found dexamethasone to inhibit the [Ca2+]i increase in MG-63 cells following stimulation and to reduce considerably COX-2 expression via the genomic pathway. In contrast, celecoxib did not show any measurable short-term or long-term effects on the parameters of bone physiology measured.

Achskorrektur bei Knietotalendoprothesenrevisionen

Implant malalignment is a major cause for early loosening, increased wear, painful limitation of motion, and patient dissatisfaction in total knee arthroplasty. Validated diagnostic algorithms and a deeper understanding of the pathological mechanisms underlying functional deficits and pain resulting from malalignment explain the increasing number of revision operations on unloosened prostheses, which are now nearly as common as revisions for implant loosening. Common reasons are component malpositioning are a shifted joint line, or a non-physiological patella position. The success of any revision procedure basically depends on: (1) correct component positioning, (2) equal and symmetrical flexion and extension gaps, (3) restoration of joint line, and (4) a physiological patella height. The adequate grade of implant constraint has to be determined intra-operatively. A higher loosening rate of constrained implants as well as increased wear and painful limitation of motion in case of instability have to be taken into account. In the present work, a diagnostic and therapeutic algorithm for malalignment of knee prostheses is presented.

The management of necrosis-associated and idiopathic bone-marrow oedema of the proximal femur by intravenous iloprost

Bone-marrow oedema can occur both in isolation and in association with necrosis of bone, but it has not been shown whether each respond to the same methods of treatment.

We treated 16 patients with isolated oedema and 17, in which it was associated with necrosis of the proximal femur, with the prostacyclin derivative iloprost, which has been shown to be effective in the idiopathic form. The Harris hip score, the range of movement, the extent of the oedema as measured by MRI, pain on a visual analogue scale and patient satisfaction were recorded before and subsequent to treatment.

In both groups, we were able to show a significant improvement (p < 0.001) in these observations during the period of follow-up indicating that iloprost will produce clinical improvement in both circumstances.

Endothelin-1 is secreted after total knee arthroplasty regardless of the use of a tourniquet

Early infections and wound healing disorders after implantation of a total knee replacement occur regardless of the intraoperative use of a tourniquet. The biochemical regulatory processes responsible for the disturbances in microcirculation and thus the potential therapeutic options have yet to be elucidated. The hypothesis of the present paper was that endothelin-1 (ET-1), a mediator of microcirculation disturbances in parenchymatous organs, also is released after major operations on peripheral joints. The concentration of ET-1 in the plasma was determined preoperatively and at 10 postoperative time points (5 min-48 h) with (group A, n=10) and without the use of a tourniquet (group B, n=10). The ET-1 concentration achieved its maximum 6h after opening the tourniquet, which corresponded to 3.3 times the preoperative value. Without a tourniquet, the concentration maximum (2.9 times the baseline value) was achieved already 1.5 h after the end of the operation. However, the total amount of ET-1 secreted over 24 h was identical in both groups (p>0.5). We conclude that the tissue hypoxia resulting from the use of a tourniquet modulates ET-1 secretion, but that traumatization during the operation has a much stronger influence on the total amount secreted. ET-1 antagonists thus should be discussed for the drug prophylaxis of wound healing disorders, regardless of the use of a tourniquet.

[Factors influencing perioperative morbidity and mortality in primary hip arthroplasty]

INTRODUCTION

In the present study we examined preoperative parameters that may identify patients at high risk for postoperative complications after endoprosthetic joint replacement.

MATERIALS AND METHODS

The incidence of risk factors and perioperative complications in 628 primary hip arthroplasties (THA) (549 patients) was investigated in an unselected, retrospective study. Concomitant illnesses were found in 426 cases. Intra- and postoperative complications (93 specifically orthopedic and 42 common ones) were observed in 104 cases.

RESULTS

High risk scores based on Lutz and Klose criteria, a prolonged operation time, and the number of previous operations were significantly correlated to the incidence of postoperative complications. In contrast, obese patients had a significantly lower rate of intra- and postoperative complications and a diminished perioperative blood loss. THAs performed under intubation anesthesia led to a higher blood transfusion volume. The patient's age and the kind and quantity of concomitant illnesses did not influence the perioperative complication rate.

CONCLUSION

The complication rate of elective primary THAs is not dependent on risk factors suspected up to now such as advanced patient age or the kind and quantity of concomitant illnesses. High-risk patients can only be determined by complex scores, not by single parameters. Adiposity becomes a relevant economic factor only by dint of the prolonged operation time.