Increasing grades of frontal deformities in knee osteoarthritis are not associated with ligamentous ankle instabilities.

PURPOSE: Varus or valgus deformities in knee osteoarthritis may have a crucial impact on ankle subtalar range of motion (ROM) and ligamentous stability. The purpose of this study was to assess whether the grade of ankle eversion and inversion rotation stability was influenced by frontal deformities of the knee joint. METHODS: Patients who were planned to undergo total knee arthroplasty (TKA) were prospectively included in this study. Patients were examined radiologically (mechanical tibiofemoral angle (mTFA), hindfoot alignment view angle (HAVA), anterior distal tibia angle (ADTA)) and clinically (ROM of the knee and ankle joint, foot function index, knee osteoarthritis outcome score). Ankle stability was assessed using an ankle arthrometer (AA) to test inversion/eversion (ie) rotation and anterior/posterior (ap) displacement stability of the ankle joint. Correlations were calculated using Pearson's coefficient, and differences between two independent groups of nonparametric data were calculated using a two-sided Wilcoxon signed rank test. RESULTS: Eighty-two (varus n = 52, valgus n = 30) patients were included. The preoperative mTFA significantly correlated with the HAVA (Pearson's correlation = - 0.72, p < 0.001). Laxity testing of the ankle demonstrated that in both varus and valgus knee osteoarthritis, higher grades of mTFA did not correlate with the inversion or eversion capacity of the ankle joint. The ADTA significantly correlated with the posterior displacement of the ankle joint (cor = 0.24, p = 0.049). CONCLUSIONS: This study could not confirm that higher degrees of frontal knee deformities in osteoarthritis were associated with increasing grades of ligamentous ankle instabilities or a reduced ROM of the subtalar joint. LEVEL OF EVIDENCE: II.

Recommendations for return to sports after total hip arthroplasty are becoming less restrictive as implants improve.

INTRODUCTION: Total hip arthroplasty (THA) surgeries are expected to exponentially increase in the upcoming years, likely because of the overall broader indication of THAs. With these developments, an increasing number of younger (< 50 years) and active patients will receive surgical interventions, and expectations for an active lifestyle will accordingly increase. In addition, surgeons now have a growing array of techniques and implant materials to choose from. Despite these developments, evidence to provide the best standard-of-care to patients with high expectations for return to sports (RTS) is scarce and urgently needed. What recommendations do arthroplasty surgeons currently make to patients with high return to sports expectations, what factors may influence their recommendations and what surgical techniques and implant specifications are considered favorable in the treatment of patients with a more active lifestyle? This study was conducted to analyze the current recommendations, patient assessment, and patient counseling after THA to identify trends and relevant factors for surgical decision-making in patients with high-RTS expectations. MATERIAL AND METHODS: We designed a questionnaire comprising five general items and 19 specific items that included 46 sub-items for hip arthroplasty and conducted a survey among 300 German surgeons specialized in arthroplasty at the German Arthroplasty Society (AE) to assess expert opinions, recommendations, surgical decision-making, and patient counseling for patients with high expectations for RTS after THA. RESULTS: The majority of surgeons (81.9%) were in favor of RTS after THA. Risks associated with sports after THA were considered minimal (1%), with periprosthetic fractures ranking highest, followed by hip dislocation and polyethylene wear. Some surgical decision-making was influenced by high-RTS expectations in regard to implant fixation, stem type, femoral head diameter, and bearing-surface tribology. We observed an increasingly liberal counseling of patients for high-impact sports. CONCLUSION: With the improvement of implants and surgical techniques, surgeons are more willing to encourage patients to adopt a more active lifestyle. However, the true long-term limitations need further investigation in future studies. LEVEL OF EVIDENCE: 5 Expert opinions.

[Diagnosis of periprosthetic joint infection : Development of an evidence-based algorithm by the work group of implant-associated infection of the AE-(German Society for Arthroplasty)]. / Diagnostik der periprothetischen Infektion : Entwicklung eines evidenzbasierten Algorithmus der Arbeitsgruppe implantatassoziierte Infektion der Arbeitsgemeinschaft Endoprothetik.

BACKGROUND: Prosthetic joint infections (PPI) will challenge orthopaedic surgeons and the health care system in the coming years. Evidence-based and reliable preoperative diagnostics are necessary for success in the field of revision arthroplasty. Especially the preoperative detection of PPI is important with respect to the treatment strategy. AIM: The aim of this study was to develop a detailed and structured standard operating procedure (SOP) to detect PPI preoperatively. METHODS: A systematic literature research was performed and relevant articles identified. After extracting the data, statistical calculations of sensitivity, specificity, positive/negative predictive value and positive/negative likelihood ratio were performed. The results were discussed and evaluated in four meetings analogously to standard Delphi rounds by the workgroup of implant-associated infections of the German AE (Arbeitsgemeinschaft Endoprothetik). An algorithm for the diagnostic approach according to ISO 5807 was made. RESULTS: The standardized algorithm combines a sequence of evidence-based procedures with detailed and structured main and additional criteria to every critical step in the diagnostic approach. CONCLUSION: The detection of PPI is of tremendous importance prior to revision arthroplasty and determines its success or failure. The diagnosis "prosthetic joint infection" requires a substantial change with respect to treatment concepts. The algorithm summarizes current literature and specialized expert opinions in a modern standardized format for a transparent diagnostic approach.

Correction of excessive intraarticular varus deformities in total knee arthroplasty is associated with deteriorated postoperative ankle function.

PURPOSE: The aim of this study was to demonstrate, whether the degree of limb alignment correction in varus knee osteoarthritis correlated with an increase in ankle symptoms and to define a cut-off value concerning the degree of correction above which to expect ankle problems. METHODS: Ninety-nine consecutive patients with preoperative intraarticular varus knee deformities who underwent total knee arthroplasty were retrospectively analyzed. Patients were examined clinically (Knee Society Score, Forgotten Joint Score, Foot Function Index, Range of Motion of the knee and ankle joint, pain scales) as well as radiologically. The mean follow-up time was 57 months. RESULTS: The degree of operative limb alignment correction strongly correlated with the Foot Function Index (R = 0.91, p < 0.05). Given this, higher degrees of knee malalignment corrections were associated with worse postoperative outcomes in the knee and ankle joint-despite postoperative improved joint line orientations. Subsequently, a cut-off value for arthritic varus deformities (14.5°) could be calculated, above which the prevalence of ankle symptoms increased manifold [OR = 15.6 (3.2-77.2 95% CI p < 0.05)]. Furthermore, ROM restrictions in the subtalar joint were associated with a worse outcome in the ankle joint. CONCLUSIONS: When correcting excessive intraarticular varus knee osteoarthritis, surgeons have to be aware of possible postoperative ankle symptoms and should consider ankle deformities or decreased subtalar ROM before operative procedures. LEVEL OF EVIDENCE: III.

Accuracy of tibial positioning in the frontal plane: a prospective study comparing conventional and innovative techniques in total knee arthroplasty.

BACKGROUND: Coronal alignment of the tibial component determines functional outcome and survival in total knee arthroplasty (TKA). Innovative techniques for tibial instrumentation have been developed to improve accuracy and reduce the rate of outliers. METHODS: In a prospective study, 300 patients were allocated to four different groups using a randomization process (two innovative and two conventional) techniques of tibial instrumentation (conventional: extramedullary, intramedullary; innovative: navigation and patient-specific instrumentation (PSI); n = 75 for each group). The aims were to reconstruct the medial proximal tibial angle (MPTA) to 90° and the mechanical tibio-femoral axis (mTFA) to 0°. Both angles were evaluated and compared between all groups three months after the surgery. Patients who presented with a postoperative mTFA > 3° were classified as outliers. RESULTS: The navigation and intramedullary technique both demonstrated that they were significantly more precise in reconstructing a neutral mTFA and MPTA compared to the other two techniques. The odd's ratio (OR) for producing outliers was highest for the PSI method (PSI OR = 5.5, p < 0.05; extramedullary positioning OR = 3.7, p > 0.05; intramedullary positioning OR = 1.7, p > 0.05; navigation OR = 0.04, p < 0.05). We could only observe significant differences between pre- and postoperative MPTA in the navigation and intramedullary group. The MPTA showed a significant negative correlation with the mTFA in all groups preoperatively and in the extramedullary, intramedullary and PSI postoperatively. CONCLUSION: The navigation and intramedullary instrumentation provided the precise positioning of the tibial component. Outliers were most common within the PSI and extramedullary technique. Optimal alignment is dependent on the technique of tibial instrumentation and tibial component positioning determines the accuracy in TKA since mTFA correlated with MPTA pre- and postoperatively.

[Open repair of gluteus medius and minimus tendons tears with double-row technique : Clinical and radiological results]. / Offene Refixation von Gluteus medius und minimus in Double-Row-Technik : Klinische und radiologische Ergebnisse.

BACKGROUND: Operative refixation is a new therapeutic option in cases of failed conservative treatment for trochanteric pain syndrome (TPS) and lesions of the hip abductors in magnetic resonance imaging (MRI). OBJECTIVE: Evaluation of the clinical and radiological results after open gluteus medius and minimus tendon reconstruction with a double-row technique was carried out. MATERIAL AND METHODS: Patients with failed conservative treatment for TPS and confirmed lesions of the hip abductors in MRI were treated by open hip abductor tendon reconstruction with a double-row technique. The patients were evaluated preoperatively and postoperatively (minimum follow-up 12 months) using the modified Harris hip score (mHHS) and a subjective score (subjective hip value, SHV). Preoperative and postoperative MRI evaluation included measurement of hip abductor muscle diameter and cross-sectional area as well as fatty degeneration. RESULTS: In this study 12 consecutive cases of open reconstruction of the hip abductor tendons were included. There was a significant improvement in the mHHS. In one case the patient showed an atraumatic rupture in the proximal anchor row. The MRI showed a significant improvement in muscle diameter and cross-sectional area for the gluteus medius muscle of the affected and the contralateral side, while the degree of fatty degeneration did not improve. The fatty degeneration showed a significant correlation with the postoperative results in the mHHS and the SHV. CONCLUSION: Operative reconstruction of lesions in the hip abductor tendons is a therapy option with significant improvement of patient satisfaction and functional scores as well as muscle diameter and cross-sectional area for the gluteus medius. The degree of fatty degeneration and possible differential diagnoses need to be taken into consideration.

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.

Mid-Term Survival of Total Knee Arthroplasty in Patients with Posttraumatic Osteoarthritis.

PURPOSE OF THE STUDY There is limited evidence on survival and complication rates in patients after total knee arthroplasty for posttraumatic osteoarthritis. The failure mechanisms leading to revision remain an issue of constant debate. The purpose of this study was to analyze the mid-term survival of primary total knee arthroplasties as well as to evaluate complications and failure mechanisms in patients with posttraumatic knee osteoarthritis. MATERIAL AND METHODS This retrospective study included 79 patients with an average age of 59 years at the time of primary total knee arthroplasty. A functional and radiographic assessment was obtained during outpatient clinical follow-up at 3 and 12 months postoperatively and yearly intervals after that. Survival rates were calculated using Kaplan-Meier analyses. The mean postoperative follow-up was 69 months. RESULTS At 69 month the revision-free survival rate was 88.6%. In nine cases (11.4%) a revision procedure was performed. The leading cause of revision was a periprosthetic infection (n = 6, 66.6%). An age of fewer than 55 years at the time of total knee arthroplasty had a significant influence on implant survival (p = 0.018) with superior survival in favor of the older patient population. At most recent follow-up, a mean Knee Society Score of 82 points and an average Function Score of 77 points were observed. CONCLUSIONS Periprosthetic joint infection is the primary failure mechanism leading to a revision in patients with total knee arthroplasty for posttraumatic osteoarthritis. Apart from the increased infection rate, total knee arthroplasties in patients with posttraumatic osteoarthritis revealed results that were comparable to patients with primary osteoarthritis. Key words:posttraumatic knee osteoarthritis, total knee replacement, survival, complications, revision, outcome.

[Surgical hip dislocation : Current status in the treatment of femoral acetabular impingement]. / Die chirurgische Hüftluxation : Derzeitiger Stellenwert in der Therapie des femoroazetabulären Impingements.

INTRODUCTION: Surgical hip dislocation (SHD) in the therapy of femoral acetabular impingement (FAI) has been mostly replaced by minimally invasive techniques. Nevertheless, in the circumstances of complex FAI types and combined impingement located in inaccessible areas of the hip, SHD is an option to reach those deformities. The advantage of the complete overview of the hip joint enables the circumferential therapy of bony deformity, but at the expense of higher invasivity. In the literature there is still a lack of mid to long-term studies of SHD to determine the overall treatment outcome. Therefore, the aim of this study is to evaluate the treatment outcome, risks and complications of SHD in FAI therapy within a mid-term follow-up. METHODS: A total of 43 patients (mean follow-up 54 months.) with combined ventral and dorsal impingement who undertook SHD were retrospectively reviewed. Outcome parameters were range of motion (ROM), the Harris hip score (HHS), the hip outcome score (HOS), the activity level, pain, complications, conversion to total hip arthroplasty (THA) and patient specific surveys. Additionally, radiographs and the influence of preoperative osteoarthrosis were evaluated. RESULTS: We were able to demonstrate a significant increase of ROM, HHS (69 â†’ 80 Pkt.; p < 0.05), hip function and a decrease in pain level. The return to sport rate was 81%, but in most cases the patients had to reduce the intensity or change to a low impact sport activity. Overall, 75% were satisfied with the treatment outcome. The alpha angle improved from 70 to 45° (p < 0.05). Patients with preoperatively advanced hip osteoarthrosis showed no decent improvement of hip function. Conversion to THA was necessary in 36% of cases. The complication rate was about 13%. CONCLUSION: SHD is successful in the treatment of combined ventral and dorsal impingement within a mid-term follow-up. The improvement of hip function and the reduction of pain symptoms is possible. In case of a manifest arthrosis an indication for SHD is no longer reasonable.

[Treatment of acetabular defects with the trabecular metal revision system]. / Defektadaptierte azetabuläre Versorgung mit der Trabecular-Metal-Technologie.

BACKGROUND: The results after acetabular component revision are very heterogeneous, irrespective of the use of established or new components. This could be due to a lack of treatment standards for new revision components. The Trabecular Metal™ (TM) revision system, through its modularity, allows for an individual intraoperative reconstruction of the acetabular defect with a single implant system. It was the aim of this study to investigate the results of acetabular revision with the TMT system taking into consideration the utilized components and the acetabular defect. METHODS: A total of 200 consecutive isolated revisions of the acetabular component from 2010 until 2012 were retrospectively analyzed from our institutional database. Of the 200 cases, 114 revisions were performed with a combination of different TMT components (wedge and cup, cup and cage). Aseptic cup failure and revision for any reason were the defined endpoints of this study. The acetabular defects were graded according to the Paprosky classification. RESULTS: The average patient age was 63.6 ± 14.8 years (range 32-85 years) and the average follow-up was 5.3 ± 0.7 years. The overall revision rate, independent of the utilized components, was 4.4% and the revision rate for aseptic failure of the acetabular component was 2.6%. The revision rate for aseptic loosening for Paprosky type I and II defects was 0% and Paprosky type III and IV defects was 12%. CONCLUSIONS: The modular TMT system shows low revision rates. The modularity of the system allows for a safe and intraoperative adaptation to the individual acetabular defect without the need for extensive preoperative imaging or custom-made implants.

Microstructural Changes of Tensor Fasciae Latae and Gluteus Medius Muscles Following Total Hip Arthroplasty: A Prospective Trial.

PURPOSE OF THE STUDY Although total hip arthroplasty (THA) is one of the most successful orthopedic operations, the soft tissue trauma towards the periarticular musculature during surgical approaches remains a critical concern. However, the actual microstructural proof of muscle trauma on the level of the myofiber due to the surgical approach has never been claimed. MATERIAL AND METHODS Patients undergoing THA were prospectively enrolled and either operated by a direct lateral (DL) or a anterolateral minimally invasive approach (ALMI). Intraoperatively and at 6 months follow-up a needle biopsy was taken from the gluteus medius muscle and the tensor fasciae latae. Pre- and post-operative fiber diameter and composition, of gluteal medius muscle (GMM) and the tensor fasciae latae muscle (TFLM) were compared in both surgical approaches. RESULTS A total of 19 patients (12 F; 7 M) were included in this study. The average pre-operative fiber diameter or fiber type composition did not differ significantly in the GMM and TFLM, nor did it vary among patients with different approaches. The muscle fiber diameter significantly increased post-operatively in the TFLM, in both, the DL (p = 0.043) and the ALMI (p = 0.043) approach. There was a trend towards more pronounced muscle fiber changes in the DL (TFLM: p = 0.077; GMM: p = 0.150), compared to the ALMI. DISCUSSION AND CONCLUSIONS Our results show microstructural changes to the periarticular musculature following THA by a compensatory hypertrophy of the TFLM and GMM. These adaptions directly next to the surgical trauma were observed in DL and AMLI. Key words: total hip arthroplasty, skeletal muscle, muscle biopsy, iatrogenic trauma, muscle scar.

Cemented Hemiarthroplasties Are Associated with a Higher Mortality Rate after Femoral Neck Fractures in Elderly Patients.

PURPOSE OF THE STUDY The postoperative outcomes of total hip replacement and hemiarthroplasty after femoral neck fractures in elderly patients were analysed to determine general and local complications as well as morbidity and mortality rates in order to detect risk profiles and assess the best individual treatment option. MATERIALS AND METHODS One hundred sixty-one femoral neck fractures among patients aged ≥ 65 years treated with cemented hemiarthroplasty (HA) or uncemented total hip arthroplasty (THA) between January 2005 and October 2013 were evaluated. In the presence of articular pathologies as well as a fracture type Garden III or IV, the indication for joint replacement was given. Criteria for performing hemiarthroplasty were previously limited mobility. Freely and fully mobilised patients and patients with manifested osteoarthritis received a cementless THA. A comparison of the observed complications was made, differentiating between general and surgery-specific hip-related complications. Furthermore, the mortality rates were analysed in relation to the respective surgical treatment. RESULTS Seventy cemented HA and ninety-one uncemented THA were performed. There was a high complication rate of approximately 19% in both surgical intervention groups. The patients were more likely to develop general complications (HA 12.8%; THA 10.8%) even though cardiopulmonary complications occurred more frequently in the cemented HA group. Four patients died after cemented hemiarthroplasty due to thromboembolic events (5.7% mortality rate), whereas no deaths occurred after total hip replacement. Surgery-specific complications rates were 7.8% in THA and 5.7% in HA patients. CONCLUSIONS THA in eldery patients with femoral neck fractures is associated with a higher complication rate, mostly of general medical entity. After cemented HA, our study reveals a high mortality rate due to thromboembolic events. For patients with multimorbidity in particular, these findings therefore suggest that uncemented THA should be considered to prevent lethal complications. Key words: femoral neck fracture; total hip arthroplasty; hemiarthroplasty; complications.

Combined arthroscopic tenodesis of the long head of biceps and rotator cuff repair in antero-superior cuff tears.

PURPOSE AND HYPOTHESIS: This study evaluates the functional and cosmetic results following fixation of the long head of the biceps (LHB) tendon at the antero-medial footprint anchor of a rotator cuff reconstruction, using the "lasso-loop" technique. METHODS: 39 patients with a mean age of 62 years with a rotator cuff tear and associated lesion of the LHB tendon were included in this study. Besides rotator cuff repair in an arthroscopic anchor technique, all patients received additional LHB tenodeses using the lasso-loop technique. Clinical follow-up consisted of the Constant score (CS), LHB score, DASH score, and WORC index. Relevant sub-items, such as elbow flexion strength and cosmesis, were compared to the contralateral arm. RESULTS: At an average follow-up of 22 months (11-39 months), the CS resulted in an average of 81 points. The biceps-specific LHB score showed a mean value of 89 points. The analysis of the DASH score showed an average of 16.9 points and the analysis of the WORC index showed an average result of 79.7 %. Distalization of the biceps muscle was objectively in three cases (7.7 %) (as observed by the examiner) and subjectively in one of those cases (as noted by the patient). There was a loss in elbow flexion strength compared to the contralateral side; however, this loss was not statistically significant and not associated with clinical apparent re-tear or insufficiency of the tenodesis. DISCUSSION: The arthroscopic lasso-loop tenodesis of the LHB tendon is a time and cost-efficient technique. No additional anchor is needed when included in the rotator cuff repair. Functional and cosmetical results as well as results from the biceps-specific LHB score were good to excellent. The loss in elbow flexion strength is most likely associated with concomitant rotator cuff lesion. CONCLUSION: The lasso-loop fixation technique of the LHB tendon using the antero-medial footprint anchor in rotator cuff tears is a reliable and cost-efficient procedure. LEVEL OF EVIDENCE: III.

[Management of periprosthetic infections of the knee]. / Management periprothetischer Infektionen des Kniegelenks.

Endoprosthetic replacement is one of the most successful operations in current medicine. As the implantation of knee prostheses increases, the number of periprosthetic infections is also rising. In case of painful or early loosening of the prosthesis an infection should be excluded by joint aspiration. Retention of the prosthesis with change of mobile parts is possible only in acute infections (< 4 weeks after surgery or duration of symptoms of <3 weeks in the case of hematogenous infection), if the prosthesis is stable, the soft tissue is intact, and no difficult-to-treat pathogens were found. In other cases a one- or two-stage prosthesis exchange should be performed. In a two-stage exchange, a short interval of 2-3 weeks is possible, if biofilm-active treatment is available. Rifampin should be used targeted (after isolation of the pathogen) and only in combination with another efficient antibiotic. In this article the current management concepts of periprosthetic infection of the knee are discussed.

[Periprosthetic infections in patients with rheumatism : A challenge]. / Periprothetische Infektion des rheumatologischen Patienten : Eine Herausforderung.

The increasing number of implantations will lead to more periprosthetic infections. Periprosthetic infections in patients with rheumatism, who are often undergoing immunosuppressive treatment, represent a challenge for the treating physicians. The optimal care and treatment therefore necessitate an interdisciplinary agreement between orthopedic surgeons, specialists for infections and rheumatologists.

[The Berlin diagnostic algorithm for painful knee TKA]. / Berliner diagnostischer Algorithmus der schmerzhaften Knie-TEP.

BACKGROUND: Approximately 20% of patients are unsatisfied with their postoperative results after total knee arthroplasty (TKA). Main causes for revision surgery are periprosthetic infection, aseptic loosing, instability and malalignment. In rare cases secondary progression of osteoarthritis of the patella, periprosthetic fractures, extensor mechanism insufficiency, polyethylene wear and arthrofibrosis can cause the necessity for a reintervention. Identifying the reason for a painful knee arthroplasty can be very difficult, but is a prerequisite for a successful therapy. AIM: The aim of this article is to provide an efficient analysis of the painful TKA by using a reproducible algorithm. DISCUSSION: Basic building blocks are the medical history with the core issues of pain character and the time curve of pain concerning surgery. This is followed by the basic diagnostics, including clinical, radiological, and infectiological investigations. Unique failures like periprosthetic infection or aseptic loosening can thereby be diagnosed in the majority of cases. If the cause of pain is not clearly attributable using the basic diagnostics tool, further infectiological investigation or diagnostic imaging are necessary. If the findings are inconsistent, uncommon causes of symptoms, such as extra-articular pathologies, causalgia or arthrofibrosis, have to be considered. In cases of ongoing unexplained pain, a revision is not indicated. These patients should be re-evaluated after a period of time.

[Quadriceps tendon insufficiency and rupture : Treatment options in total knee arthroplasty]. / Quadrizepssehneninsuffizienzen und -rupturen : Verfahren zur Behandlung in der Knieendoprothetik.

Quadriceps tendon injuries and insufficiencies in total knee arthroplasty are rare, but are followed by a devastating complication that left untreated leads to a complete loss of function of the knee. This review article summarizes the functional anatomy, risk factors, and the prevalence and diagnosis of quadriceps tendon injuries, in addition to the possible management options for partial and complete ruptures. The treatment options are adapted according to the extent of the loss of function (partial, complete) and the duration of the injury (acute vs chronic). Furthermore, the choice of treatment should take into account the quality and availability of primary tissue, the patient's general health, along with their likely functional requirements. Conservative treatment is often justified in partial ruptures with good results. Complete ruptures require surgical intervention and multiple operative techniques are described. Treatment options for acute ruptures include direct primary repair with autogenous or synthetic tissue augmentation. In the case of chronic insufficiency and a lack of soft-tissue surroundings, reconstruction with the aid of a muscle flap or allograft tissue can be considered. All surgical intervention techniques used so far have been fraught with complications and rarely lead to satisfactory results. A new surgical approach to the reconstruction and augmentation of the extensor mechanism consists of the use of a synthetic mesh. The technique is described here in detail.

[Periprosthetic fractures following total hip and knee arthroplasty: Risk factors, epidemiological aspects, diagnostics and classification systems]. / Periprothetische Frakturen nach Hüft- und Knietotalendoprothesenimplantation: Risikofaktoren, epidemiologische Aspekte, Diagnostik und Klassifikationssysteme.

Periprosthetic fractures following hip and knee arthroplasty are potentially severe complications. As a fundament in diagnostic and therapeutic procedures, specific classification systems are necessary to ensure an optimal individualized treatment of these sometimes complicated fractures. This review article summarizes the epidemiological aspects, risk factors and diagnostics of periprosthetic hip and knee fractures. The most frequently used location related fracture classifications systems are explained. In addition, the recently introduced unified classification system (UCS), which is applicable to any location of periprosthetic fractures, is described in detail. Initial studies have shown a reliable applicability of the UCS to periprosthetic hip and knee fractures.

High-dose electron beam sterilization of soft-tissue grafts maintains significantly improved biomechanical properties compared to standard gamma treatment.

Allografts have gained increasing popularity in anterior cruciate ligament (ACL) reconstruction. However, one of the major concerns regarding allografts is the possibility of disease transmission. Electron beam (Ebeam) and Gamma radiation have been proven to be successful in sterilization of medical products. In soft tissue sterilization high dosages of gamma irradiation have been shown to be detrimental to biomechanical properties of grafts. Therefore, it was the objective of this study to compare the biomechanical properties of human bone-patellar tendon-bone (BPTB) grafts after ebeam with standard gamma irradiation at medium (25 kGy) and high doses (34 kGy). We hypothesized that the biomechanical properties of Ebeam irradiated grafts would be superior to gamma irradiated grafts. Paired 10 mm-wide human BPTB grafts were harvested from 20 donors split into four groups following irradiation with either gamma or Ebeam (each n = 10): (A) Ebeam 25 kGy, (B) Gamma 25 kGy, (C) Ebeam 34 kGy (D) Gamma 34 kGy and ten non-irradiated BPTB grafts were used as controls. All grafts underwent biomechanical testing which included preconditioning (ten cycles, 0-20 N); cyclic loading (200 cycles, 20-200 N) and a load-to-failure (LTF) test. Stiffness of non-irradiated controls (199.6 ± 59.1 N/mm) and Ebeam sterilized grafts did not significantly differ (152.0 ± 37.0 N/mm; 192.8 ± 58.0 N/mm), while Gamma-irradiated grafts had significantly lower stiffness than controls at both irradiation dosages (25 kGy: 126.1 ± 45.4 N/mm; 34 kGy: 170.6 ± 58.2 N/mm) (p < 0.05). Failure loads at 25 kGy were significantly lower in the gamma group (1,009 ± 400 N), while the failure load was significantly lower in both study groups at high dose irradiation with 34 kGy (Ebeam: 1,139 ± 445 N, Gamma: 1,073 ± 617 N) compared to controls (1,741 ± 304 N) (p < 0.05). Creep was significantly larger in the gamma irradiated groups (25 kGy: 0.96 ± 1.34 mm; 34 kGy: 1.06 ± 0.58 mm) than in the Ebeam (25 kGy: 0.50 ± 0.34 mm; 34 kGy: 0.26 ± 0.24 mm) and control (0.20 ± 0.18 mm) group that did not differ significantly. Strain difference was not different between either control or study groups (controls: 1.0 ± 0.03; Ebeam 34 kGy 1.04 ± 0.018; Gamma 34 kGy 1.0 ± 0.028; 25 kGy: 1.4 ± 2,0; 34 kGy: 1.1 ± 1.1). The most important result of this study was that ebeam irradiation showed significantly less impairment of the biomechanical properties than gamma irradiation. Considering the results of this study and the improved control of irradiation application with electronic beam, this technique might be a promising alternative in soft-tissue sterilization.

Improved identification of polymicrobial infection in total knee arthroplasty through sonicate fluid cultures.

INTRODUCTION: Periprosthetic joint infection (PJI) is the leading cause for early failure of total knee arthroplasty (TKA). An insufficient diagnosis of the involved bacterial species can be a possible cause for this high failure rate. Sonicate fluid cultures (SFC) have been shown to increase the detection rate of PJI in comparison to the use of conventional microbiological methods. The hypothesis of this study is that sonication will improve not only the detection rate of PJI, but also the detection rate of polymicrobial infection in patients with TKA revision surgery. MATERIALS AND METHODS: 109 patients, undergoing TKA revision surgery, were enrolled in this prospective cohort study and received a synovial aspiration, intraoperative tissue cultures, histological sampling of the periprosthetic membrane (PM), and sonication of the explanted endoprosthesis. A PJI was defined according to the following criteria: presence of intraarticular pus or a sinus tract, positive isolation of the same bacterial species in ≥2 microbiological samples or a PM indicative of infection. RESULTS: 31 patients had a defined PJI according to the above-mentioned criteria. SFC achieved the highest sensitivity (74 %) of all microbiological methods. The PM achieved a sensitivity of 87 %. When the results of the SFC and the PM were combined, it was possible to further increase the sensitivity to 94 %. The utilization of SFC doubled the number of polymicrobial bacterial isolations in our patient collective. There were 12 cases of polymicrobial bacterial isolations, six were detectable through conventional microbiological methods, four were detectable through SFC and two were identifiable as polymicrobial through the isolation of an additional bacterial species in the SFC. CONCLUSIONS: In our study, SFC were the most sensitive microbiological method and were surpassed only by the histology. The use of SFC doubled the detection rate of polymicrobial isolations, which would be missed with conventional microbiological methods alone.