[Isolated Patellofemoral Osteoarthritis]. / Isolierte Patellofemoralarthrose.

Isolated patellofemoral osteoarthritis is a complex pathology. It occurs frequently in women over 40 years and leads to a high degree of suffering. The causes of femoropatellar degeneration are manifold and require stage-specific therapy. This is very challenging for the treating physician. This article is intended to provide a structured overview of the symptoms, diagnostics and stage-specific therapy of patellofemoral osteoarthritis.

Patients with Small Acetabular Cartilage Defects Caused by Femoroacetabular Impingement Do Not Benefit from Microfracture.

OBJECTIVE: According to current recommendations, large cartilage defects of the hip over 2 cm2 are suggested to undergo autologous chondrocyte transplantation (ACT), while small defects should be treated with microfracture. We investigated if patients with small chondral defects of the hip joint (≤100 mm2) actually benefit from microfracture. DESIGN: In this retrospective multicenter cohort study 40 patients with focal acetabular cartilage defects smaller than 100 mm2 and of ICRS grade ≥2 caused by femoroacetabular impingement were included. Twenty-six unrandomized patients underwent microfracture besides treatment of the underlying pathology; in 14 patients cartilage lesions were left untreated during arthroscopy. Over a mean follow-up of 28.8 months patient-reported outcome was determined using the iHOT33 (international hip outcome tool) and the VAS (visual analog scale) for pain. RESULTS: The untreated group showed a statistically significant improvement of the iHOT33 after 12 (p = 0.005), 24 (p = 0.019), and 36 months (p = 0.002) compared to the preoperative score, whereas iHOT33 in the microfracture group did not reveal statistically significant changes over time. There was no significant difference between both groups on any time point. Regarding pain both groups did not show a significant improvement over time in the VAS. CONCLUSION: The subjective outcome of patients with small cartilage defects of the hip (≤100 mm2) improves 12 months after arthroscopic FAIS surgery without any cartilage treatment. However, no improvement could be seen after microfracture. Therefore, a reserved surgical treatment for small cartilage defects of the hip under preservation of the subchondral bone is recommended especially if a simultaneous impingement correction is performed.

[Persistent or recurrent symptoms after surgery for femoroacetabular impingement syndrome (FAIS) : Pathology, diagnostics and therapy]. / Persistierende oder wiederkehrende Beschwerden nach femoroazetabulärer Impingement-Chirurgie : Ursachen, Diagnostik und Therapie.

BACKGROUND: Femoroacetabular impingement syndrome (FAIS) has gained vast importance in the last two decades. Multiple studies have shown that if untreated, early osteoarthritis of the hip joint may result. Hip arthroscopy is one of the fastest growing procedures in the orthopedic cosmos, having already replaced the majority of (mini) open techniques in FAIS surgery. However, with the recent remarkable increase in the volume of hip arthroscopies performed worldwide, the number of patients with persistent or recurrent symptoms after FAIS surgery is also growing. PATHOLOGY: Potential underlying pathologies are misresection of the bony deformity, insufficiency fracture of the femoral head neck junction or the femoral subchondral head itself (SIFFH), adhesions, failed chondrolabral or capsular treatment, septic arthritis, heterotopic ossification or a wrong indication in the case of osteoarthritis that is already too advanced. Most of these occur more often during the extensive learning curve for hip arthroscopy. DIAGNOSTICS: High-quality imaging plays a key role in determining the need for revision surgery vs. further conservative treatment. Therapeutical avenues are shown with the common goal of proper detection and correction of the underlying pathology to address unsatisfactory FAIS treatment outcomes and ensure long-term survival of the native hip joint.

Dysregulation of Wnt signaling in bone of type 2 diabetes mellitus and diabetic Charcot arthropathy.

BACKGROUND: Type 2 diabetes mellitus (T2DM) patients show a markedly higher fracture risk and impaired fracture healing when compared to non-diabetic patients. However in contrast to type 1 diabetes mellitus, bone mineral density in T2DM is known to be normal or even regionally elevated, also known as diabetic bone disease. Charcot arthropathy is a severe and challenging complication leading to bone destruction and mutilating bone deformities. Wnt signaling is involved in increasing bone mineral density, bone homeostasis and apoptotic processes. It has been shown that type 2 diabetes mellitus is strongly associated with gene variants of the Wnt signaling pathway, specifically polymorphisms of TCF7L2 (transcription factor 7 like 2), which is an effector transcription factor of this pathway. METHODS: Bone samples of 19 T2DM patients and 7 T2DM patients with additional Charcot arthropathy were compared to 19 non-diabetic controls. qPCR analysis for selected members of the Wnt-signaling pathway (WNT3A, WNT5A, catenin beta, TCF7L2) and bone gamma-carboxyglutamate (BGLAP, Osteocalcin) was performed and analyzed using the 2-ΔΔCt- Method. Statistical analysis comprised one-way analysis of variance (ANOVA). RESULTS: In T2DM patients who had developed Charcot arthropathy WNT3A and WNT5A gene expression was down-regulated by 89 and 58% compared to healthy controls (p < 0.0001). TCF7L2 gene expression showed a significant reduction by 63% (p < 0.0001) and 18% (p = 0.0136) in diabetic Charcot arthropathy. In all diabetic patients BGLAP (Osteocalcin) was significantly decreased by at least 59% (p = 0.0019). CONCLUSIONS: For the first time with this study downregulation of members of the Wnt-signaling pathway has been shown in the bone of diabetic patients with and without Charcot arthropathy. This may serve as future therapeutic target for this severe disease.

Outcome-Affecting Parameters of Hip Arthroscopy for Femoroacetabular Impingement with Concomitant Cartilage Damage-Data Analysis from the German Cartilage Registry.

This study aims to report on a prospectively collected, multicenter database of patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAI) and concomitant cartilage damage (according to the International Cartilage Repair Society) and to assess the outcome-affecting parameters. In the study, 353 hips with up to 24 months' follow-up were assessed by iHOT-33 scoring and achievement of the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) levels. Multiple and binary regression analyses were performed to identify factors related to (un-) favorable outcomes and to assess their clinical relevance with regard to achieving the MCID and PASS. Multiple regression yielded the parameters of male sex (p = 0.022) and lower body mass index (BMI) (p = 0.019) at 6 months, lower BMI (p = 0.022) and younger age (p = 0.022) at 12 months, and younger age at 24 months (p = 0.039) to be significantly associated with higher iHOT scoring. Male sex (p = 0.019) and lower BMI (p = 0.018) were significantly correlated with achievement of the PASS in binary regression at 6 months, whereas at 12 (p = 0.010) and at 24 (p = 0.003) only younger age was shown to be significantly correlated. None of the parameters was statistically associated with achievement of the MCID. As the parameters of younger age, male sex, and lower BMI were identified as temporarily correlated with a preferable outcome in general and with achievement of the PASS in particular, these findings help to preoperatively identify factors associated with (un-) favorable therapy results.

[Epidemiology, prevention and early detection of femoroacetabular impingement syndrome (FAIS)]. / Epidemiologie, Prävention und Früherkennung des Femoroazetabulären Impingement-Syndroms (FAIS).

During the last two decades femoroacetabular impingement syndrome (FAIS) has gained importance and is one of the main causes of hip pain in young adults. FAIS is a motion-related clinical pathology of the hip that represents symptomatic contact between the proximal femur and the acetabulum. Symptoms, clinical signs, and imaging findings must be present to diagnose FAIS. Especially the development of the cam-FAIS seems to be associated with an overuse of the growth plate during adolescence. Here an approach may be found for the prevention of the development of FAIS. Sufficient evidence through high-quality long-term results is yet lacking.

Diagnostic accuracy of multiplex polymerase chain reaction on tissue biopsies in periprosthetic joint infections.

The diagnosis and treatment of periprosthetic joint infection (PJI) currently relies on cultures, which are time-consuming and often fail. Multiplex PCR assays promise reliable and prompt results, but have been heterogeneously evaluated. In this study, we analyse multiplex PCR in pathogen identification using only tissue biopsies. 42 patients after revision arthroplasty of the hip or knee were evaluated using multiplex PCR to identify microorganisms. The patients were classified according to the diagnostic criteria published by Zimmerli et al. and the results were compared to the respective microbiological cultures. PJI was detected in 15 patients and 27 revisions were aseptic. The multiplex PCR of tissue biopsies had a sensitivity of 0.3 (95% CI 0.12-0.62), a specificity of 1.0 (0.87-1.0), a positive predictive value of 1.0 (0.48-1.0) and a negative predictive value of 0.73 (0.56-0.86). The diagnostic accuracy of multiplex PCR on tissue biopsy samples is low in comparison to routine microbiological cultures. The evaluation of tissue biopsies using multiplex PCR was prone to false negative results. However, multiplex PCR assays have the advantage of rapid pathogen identification. We therefore recommend further investigation of multiplex PCR in the setting of suspected PJI with a careful choice of specimens.

Antimicrobial peptides in human synovial membrane as (low-grade) periprosthetic joint infection biomarkers.

BACKGROUND: Safe diagnosis of periprosthetic joint infection (PJI) is of utmost importance for successful exchange arthroplasty. However, current diagnostic tools show insufficient accuracy in the clinically common and challenging chronic low-grade infections. To close this diagnostic gap, reliable (bio)markers display the most promising candidates. Antimicrobial peptides (AMPs) are part of the innate immune response towards microbial growth. Recently we could show significant intraarticular levels of human cathelicidin LL-37 and ß-defensin-3 (HBD-3) with high diagnostic accuracy in PJI synovial fluid. Consequently, these promising biomarkers were evaluated in PJI synovial membrane and synoviocytes, which may significantly facilitate histological diagnosis of PJI to improve outcome of septic joint replacement. METHODS: In this prospective single-center controlled clinical study (diagnostic level II), consecutive patients with total hip (THR) and knee (TKR) replacements were included undergoing primary arthroplasty (n = 8), surgical revision due to aseptic loosening (n = 9) and septic arthroplasty with coagulase-negative staphylococci (n = 8) according to the criteria of the Musculoskeletal Infection Society (MSIS). Semiquantitative immunohistochemical (IHC) analysis of LL-37, HBD-3 and HBD-2 in synovial membrane and isolated synoviocytes based on Total Allred Score (TS) and Immunoreactive Remmele and Stegner score (IRS) was performed. For statistical analysis, SPSS 26.0/R3.6.3 (p < 0.05) was used. RESULTS: The AMPs LL-37 and HBD-3 were significantly elevated (up to 20×) in synovial membranes from PJI compared to aseptic loosening or primary arthroplasty. The area under the curve (AUC) in a receiver operating characteristic curve analysis was equal to 1.0 for both scores revealing excellent diagnostic accuracy. Isolated synoviocytes as cellular AMP source showed comparable results with a significant LL-37/HBD-3-increase up to 3 × in PJI. In contrast, local HBD-2 levels were negligible (p > 0.23) upon PJI with a lower diagnostic accuracy (AUC = 0.65) in analogy to our previous findings with synovial fluid. CONCLUSIONS: Our results implicate AMPs as promising and specific biomarkers for the histological diagnosis of PJI.

Improved pre-operative diagnostic accuracy for low-grade prosthetic joint infections using second-generation multiplex Polymerase chain reaction on joint fluid aspirate.

BACKGROUND: A major obstacle for the treatment of prosthetic joint infection (PJI) is the identification of the underlying causative organism. While the diagnostic criteria ruling PJI in or out have become ever more accurate, the detection of the causative pathogen(s) still relies mostly on conventional and time-consuming microbial culture. The aim of this study was to evaluate the diagnostic potential of a second-generation multiplex PCR assay (Unyvero ITI G2, Curetis AG, Holzgerlingen, Germany) used on synovial fluid specimens. Our hypothesis was that the method would yield a higher diagnostic accuracy in the pre-operative workup than synovial fluid culture. Thus, a more precise classification of septic and aseptic prosthesis failure could be achieved before revision surgery. METHODS: Prospectively collected frozen joint fluid specimens from 26 patients undergoing arthroplasty revision surgery of the hip or knee were tested as per the manufacturer's protocol. Sensitivities, specificities, positive and negative predictive values as well as positive and negative likelihood ratios with corresponding confidence intervals were estimated using the statistical software R. A combination of the serum C-reactive protein (CRP) level, leukocyte count, erythrocyte sedimentation rate, joint fluid culture, tissue biopsy culture, and tissue biopsy histology served as the gold standard. RESULTS: Of the 26 patients included in the study, 15 were infected and 11 were aseptic. Conventional joint fluid culture showed a sensitivity of 0.67 and a specificity of 0.91. Joint fluid multiplex PCR yielded a sensitivity of 0.8 and a specificity of 1.0. CONCLUSIONS: Using the second-generation Unyvero ITI cartridge on joint fluid aspirate for the detection of prosthetic joint infection, we were able to achieve a higher diagnostic accuracy than with conventional culture. We conclude that to improve pathogen detection before revision surgery, this method represents a valuable and practicable tool.

[Native joint infections]. / Native Gelenkinfektionen.

Joint infections are a great challenge for the treating physicians. Infection of a native joint can result in the rapid destruction of the joint if treatment is inadequate or delayed and is associated with severe life-threatening diseases, such as sepsis. This article presents a detailed overview of the treatment of joint infections of native joints with a focus on the diagnostic approach and treatment decisions. Infections in native joints are caused either endogenously by hematogenic spreading or are caused by exogenous factors. A relevant proportion of joint infections in native joints occur in connection with iatrogenic measures, such as operations, synovial punctures and joint infiltrations. Fundamentally, acute infections represent an orthopedic surgical emergency, which is associated with the necessity for immediate operative measures. The best possible success can only be achieved by an interaction between early diagnosis, an adequate surgical approach and a tailor-made anti-infectious treatment. This is also the case with periprosthetic infections, which will be dealt with in detail in a second article.

Guided and Unguided Biopsy in the Diagnostic of Periprosthetic Infections of the Knee - Evaluation of an Evidence-based Algorithm. / Die gezielte und ungezielte Zupfbiopsie in der Abklärung periprothetischer Kniegelenksinfektionen ­ Evaluierung eines evidenzbasierten Algorithmus.

BACKGROUND: Periprosthetic joint infection (PPI) is one of the most common reasons for revision in total knee arthroplasty (TKA). Percutaneous synovial biopsy is considered as a well-established diagnostic tool in ambiguous cases of chronic pain after TKA. The exact number of undetected low-grade infections remains unclear. OBJECTIVES: The aim of this prospective study was to compare the diagnostic accuracy of arthroscopically guided and unguided synovial biopsy. Additionally, the prevalence of initially undetected PPI during synovial biopsy and revision surgery was assessed. MATERIALS AND METHODS: 40 patients suffering from chronic pain after TKA and the clinical suspicion of PPI were included in the study. Synovial biopsies were collected in a standardized manner first without and then with arthroscopic visual control. Using both techniques, six samples were collected each (5 for microbiology, 1 for histology). 19 patients, initially classified aseptic, underwent revision surgery later. RESULTS: The diagnosis of PPI was made in 10.0% of unguided biopsies (4 cases, 2× microbiologically, 2× histologically), 7.5% of arthroscopic biopsies (3 cases, 3× histologically) and 12.5% (5 cases, 3× histologically, 2× microbiologically) of all cases. Only histologic evaluation led to concordant positive findings using both techniques in two patients. The proportion of non-representative biopsies was twice as high after unguided tissue collection than after arthroscopic biopsy (30.0 vs. 15.0%). Microbiologic evaluation of arthroscopically collected biopsies did not lead to the diagnosis of PPI, which might have been essential to the selection of the appropriate antimicrobial therapy. During revision surgery the diagnosis of PPI was made in 22.2% of cases. CONCLUSIONS: In patients suffering from chronic pain after TKA, periprosthetic low-grade infection was diagnosed in a relevant proportion of cases. Therefore, synovial biopsies for histological and microbiological evaluation should be collected whenever there's clinical suspicion of PPI. For histological evaluation, samples should be collected using arthroscopic control and ideally multiple biopsies should be taken. For microbiological evaluation, excessive joint lavage should be avoided.

How to address ischiofemoral impingement? Treatment algorithm and review of the literature.

Ischiofemoral impingement (IFI) is a rare cause of hip pain defined by a narrowing of the space between the lateral aspect of the os ischium and the lesser trochanter of the femur. Several underlying anatomic, functional and iatrogenic pathologies have been identified for symptomatic IFI in native hip joints and after total hip arthroplasty. Clinical symptoms vary but most commonly consist of pain of the lower buttock and groin including the inner thigh, and a snapping or clunking phenomenon is often reported. Symptoms may be provoked by a combined extension, adduction and external rotation during physical examination and during long-stride walking. Radiographs of the pelvis and an axial or false-profile-view of the hip as well as magnetic resonance imaging (MRI)-scans should be obtained to strengthen the diagnosis. On MRI, the quadratus femoris muscle signal and the space confined by the anatomic structures surrounding the muscle, the quadratus femoris space, are to be assessed. Targeted infiltration of the muscle can be helpful both diagnostically and therapeutically. The literature on differential diagnoses and treatment options for IFI is limited; therapeutic suggestions are offered only in case reports and series. With this work, we aim to give a systematic approach to the non-surgical and surgical treatment options for IFI based upon the current literature and the authors' personal experience.

Prospective Analysis of a Sterile, Semi-automated Tissue Biopsy Homogenization Method in the Diagnosis of Prosthetic Joint Infections.

BACKGROUND/AIM: Prosthetic joint infection (PJI) remains a serious complication of total joint arthroplasty. To effectively treat PJI, it is essential to identify the microorganism causing it and be able to combine correct surgical and anti-infective treatments. This cannot always be achieved with the currently employed diagnostic methods. The aim of this study was to evaluate a semi-automated tissue biopsy bead milling method (Ultra-TurrAX, Axonlab AG; Reichenbach, Germany) based on the hypothesis that the results are more sensitive for microbe detection and less prone to contamination. MATERIALS AND METHODS: We included 35 consecutive patients undergoing 38 hip or knee arthroplasty revisions in this study. In addition to manually processed biopsies, we processed tissue specimens harvested intraoperatively using a semi-automated method. The sensitivity and specificity of both methods were calculated using MSIS criteria and sonication results as gold standards. RESULTS: For total hip arthroplasty samples were evaluated separately based on MSIS criteria as the reference standard, Ultra-TurrAX processing yielded 81% (62-100%) sensitivity and 100% specificity. Using sonication as the gold standard, a sensitivity of 80% (60-100%) and specificity of 80% (45-100%) were calculated. In total knee arthroplasty, Ultra-TurrAX processing yielded 27% (1-54%) sensitivity and 57% (20-94%) specificity when using MSIS criteria as the gold standard. Using sonication as the gold standard, a sensitivity of 60% (17-100%) and specificity of 77% (54-100%) were calculated. CONCLUSION: This is the first study to analyze bead mill processing in total hip and knee arthroplasty revisions in a consecutive patient series. The method's sensitivity was comparable to and its specificity superior to regular sample processing results reported in the literature with respect to hip arthroplasties and to both hip and knee arthroplasties collectively. With respect to total knee arthroplasties, the method fared worse in our collective, most likely due to the small number of patients in the sample. Integrating the method into the clinical workflow allowed for speedier and more efficient sample handling and processing. The theoretical advantage of a lower risk of contamination because of fewer manual processing steps is, in our opinion, valid.

Mid-term outcome following revision surgery of clavicular non- and malunion using anatomic locking compression plate and iliac crest bone graft.

BACKGROUND: Treatment of clavicular non- and malunion is still challenging. Current surgical procedures often result in frustrating functional outcome along with high-grade subjective impairment and increased rates of revision surgery. However, the combination of biological augmentation with vital bone graft and a biomechanically sufficient fixation system seems to be a promising concept of treatment. METHODS: In this retrospective study, 14 patients with a mean age of 44 years (26-67 years) suffering from non-union (n = 11) and/or malunion (n = 3) of the clavicle were enrolled. All patients were surgically treated using an anatomical precontoured locking compression plate (LCP) and autologous iliac crest bone graft. Functional outcome was assessed using the age- and sex-specific relative Constant Score. RESULTS: Mean follow-up was 27 months (range 12-44 months). The relative Constant Score significantly improved from preoperative 61 ± 8 (43-72) to 82 ± 10 (65-100) points at the final follow-up examination (p < 0.05). All patients showed bony union radiographically. One patient presented with a re-fracture of the clavicle nearly 3 years after revision surgery and 5 weeks after implant removal. Secondary fractures at the donor site of the anterior superior iliac spine were recorded in two patients. CONCLUSIONS: Iliac crest bone graft and anatomic locking plate fixation allow for a safe and adequate stabilization and radiographical bony union in non- and malunions of the clavicle with a high degree of patient satisfaction. However, secondary fractures of the anterior superior iliac spine constitute relevant complications and the time of hardware removal should be considered carefully.

Results of medial patellofemoral ligament reconstruction compared with trochleoplasty plus individual extensor apparatus balancing in patellar instability caused by severe trochlear dysplasia: a systematic review and meta-analysis.

PURPOSE: Many studies have reported satisfactory clinical outcomes and low redislocation rates after reconstruction of the medial patellofemoral ligament (MPFL) for the treatment of lateral patellar instability. Despite uncorrected severe trochlear dysplasia (Dejour type B to D) being acknowledged as a major reason for less favourable clinical outcomes and a higher incidence of patellar redislocations after an isolated MPFL reconstruction, the evidence for a deepening trochleoplasty procedure remains scarce in the current literature. The hypothesis of this systematic review and meta-analysis was that a deepening trochleoplasty in combination with an a la carte extensor apparatus balancing procedure provides lower redislocation rates and superior clinical outcomes than isolated MPFL reconstruction in patients with lateral patellar instability caused by severe trochlear dysplasia. METHODS: A systematic review of the literature was conducted using specific inclusion and exclusion criteria for clinical studies reporting index operations (trochleoplasty and MPFL reconstruction) for the treatment of patellar instability caused by severe trochlear dysplasia. The Kujala score was analysed as the primary clinical outcome parameter in a random effects meta-analysis. RESULTS: Ten uncontrolled studies with a total of 407 knees (374 patients) were included in this analysis. The MPFL group comprised 4 studies with a total of 221 knees (210 patients), and the trochleoplasty group comprised 6 studies with a total of 186 knees (164 patients). The mean preoperative Kujala score ranged between 50.4 and 70.5 in the MPFL group and between 44.8 and 75.1 in the trochleoplasty group. The pooled Kujala score increased significantly by 26.4 (95% CI 21.4, 31.3; P < 0.00001) points in the MPFL group and by 26.2 (95% CI 19.8, 32.7; P < 0.00001) points in the trochleoplasty group. The post-operative patellar redislocation/subluxation rate was 7% in the MPFL group and 2.1% in the trochleoplasty group. CONCLUSION: This analysis found significant post-operative improvements in patient-reported outcomes for patients undergoing both an MPFL reconstruction and in those undergoing a trochleoplasty plus an individual extensor apparatus balancing procedure when assessed using the Kujala score. The likelihood of preventing the patella from subsequent post-operative redislocation/subluxation was, however, greater in patients who underwent trochleoplasty plus extensor balancing. LEVEL OF EVIDENCE: IV.

Antibacterial efficacy of titanium-containing alloy with silver-nanoparticles enriched diamond-like carbon coatings.

Silver ions (Ag(+)) have strong bactericidal effects and Ag-coated medical devices proved their effectiveness in reducing infections in revision total joint arthroplasty. We quantitatively determined the antimicrobial potency of different surface treatments on a titanium alloy (Ti), which had been conversed to diamond-like carbon (DLC-Ti) and doped with high (Ag:PVP = 1:2) and low (Ag:PVP = 1:10 and 1:20) concentrations of Ag (Ag-DLC-Ti) with a modified technique of ion implantation. Bacterial adhesion and planktonic growth of clinically relevant bacterial strains (Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa) on Ag-DLC-Ti were compared to untreated Ti by quantification of colony forming units on the adherent surface and in the growth medium as well as semiquantitatively by determining the grade of biofilm formation by scanning electron microscopy. (1) A significant (p < 0.05) antimicrobial effect could be found for all Ag-DLC-Ti samples (reduced growth by 5.6-2.5 logarithmic levels). (2) The antimicrobial effect was depending on the tested bacterial strain (most for P. aeruginosa, least for S. aureus). (3) Antimicrobial potency was positively correlated with Ag concentrations. (4) Biofilm formation was decreased by Ag-DLC-Ti surfaces. This study revealed potent antibacterial effects of Ag-DLC-Ti. This may serve as a promising novel approach to close the gap in antimicrobial protection of musculoskeletal implants.