Less soft tissue release in total knee arthroplasty for anteromedial compared to posteromedial knee osteoarthritis.

In total knee arthroplasty (TKA), the aim of achieving a mechanically straight leg axis as well as symmetrical and equally wide gaps has become established as the gold standard in terms of surgical technique. In contrast to TKA unicompartmental knee arthroplasty (UKA) is performed in anteromedial osteoarthritis (AMOA) and does not normally require releases. This raises the hypothesis whether the type of osteoarthritis (AMOA vs. posteromedial osteoarthritis (PMOA)) determines the requirement for soft tissue releases in TKA.In this retrospective study, 114 patients with medial osteoarthritis of the knee who had been treated with a navigated total knee replacement were consecutively included. On the basis of the preoperative lateral radiographs, the patients were divided into two groups: AMOA and PMOA. The incidence and the extent of releases performed were recorded using the navigation records.Patient-specific data (gender, age) did not differ between the groups (NS). Knees with AMOA presented an overall varus alignment of 5.3 ± 3.5°, knees with PMOA 8.0 ± 4.0° (p < 0.001). 30 cases (44%) had to be released in the AMOA group, compared with 33 cases (72%) in the PMOA group (p = 0.004). In the case of medial release, the extension gap increased 3.3 ± 2.4 mm in the AMOA compared to 5.3 ± 3.7 mm in the PMOA group (p = 0.006). The medial flexion gap was released 2.2 ± 2.6 mm in the AMOA and 2.9 ± 3.0 mm in the PMOA group (p = 0.008).To achieve a neutral mechanical alignment, a release has to be performed due to asymmetry of the extension gap more often if PMOA is present than in AMOA. Surgeons should be prepared to perform more frequent and extensive medial releases in PMOA. Higher constrained implants should be available in case of unintended over release in PMOA.

Impact of Perioperative Dexamethasone Administration on Infection and Implant Osseointegration in a Preclinical Model of Orthopedic Device-Related Infection.

Glucocorticoids may be given prior to major orthopedic surgery to decrease postoperative nausea, vomiting, and pain. Additionally, many orthopedic patients may be on chronic glucocorticoid therapy. The aim of our study was to investigate whether glucocorticoid administration influences Orthopedic-Device-Related Infection (ODRI) in a rat model. Screws colonized with Staphylococcus epidermidis were implanted in the tibia of skeletally mature female Wistar rats. The treated groups received either a single shot of dexamethasone in a short-term risk study, or a daily dose of dexamethasone in a longer-term interference study. In both phases, bone changes in the vicinity of the implant were monitored with microCT. There were no statistically significant differences in bacteriological outcome with or without dexamethasone. In the interference study, new bone formation was statistically higher in the dexamethasone-treated group (p = 0.0005) as revealed by CT and histopathological analysis, although with relatively low direct osseointegration of the implant. In conclusion, dexamethasone does not increase the risk of developing periprosthetic osteolysis or infection in a pre-clinical model of ODRI. Long-term administration of dexamethasone seemed to offer a benefit in terms of new bone formation around the implant, but with low osseointegration.

Hip Adductor Muscle Abscess Descending From Septic Symphysitis.

Hip adductor muscle abscesses that descend from an infected symphysis pubis are rare but cause serious morbidity. We present a case of a 73-year-old male patient with unilateral hip adductor muscle abscess that descended from septic symphysitis caused by Staphylococcus aureus. Surgical debridement of the adductor compartment could not clear the infection and secondary debridement of the symphysis was necessary to eradicate S. aureus. Additionally, we review another four cases with similarities to our case comparing their investigation, treatment, and outcome.

Trauma consultations in a Swiss tertiary emergency department: Comparison of asylum seekers and the local population-Patient characteristics and patterns of injuries, a retrospective study.

BACKGROUND: In 2017, accidents and other acts of violence were the fifth most common cause of death in Switzerland. Moreover, there are increasing numbers of refugees and asylum seekers (AS), who often exhibit distinct disease profiles from those of the natives of the host country. If these differences could be clearly identified, this might help to develop and implement strategies to prevent injuries in health care programs for refugees and asylum seekers. The aim of this study was to examine the types and characteristics of physical trauma profiles in patients from the two largest groups of AS in Switzerland-from Eastern Africa (EA) and the Middle East (ME)-who consulted a Swiss Emergency Department (ED) in 2017/2018. Furthermore, the physical trauma profiles of Swiss national (SN) patients were examined in order to explore potential differences. METHODS: Descriptive retrospective study of adult trauma patients consulting the ED of a Swiss University Hospital between 01/2017 and 12/2018. The study included 157 asylum seeking trauma patients from EA and ME were included in the study. These were matched by gender and age to 157 Swiss trauma patients consulting the ED in the study period. RESULTS: There were significant differences between the groups with respect to type of admission, level of severity, localization and mechanisms of injury. While SN had higher levels of injuries related to road traffic or work, AS had higher levels of injuries related to attempted suicide or to assault. CONCLUSIONS: There were differences between AS and the local population with respect to the characteristics and patterns of injury, so that strategies for preventing injuries and promoting health must be tailored to the target population. Moreover, the observed high rates of outpatient treatment for both groups underline the increasing role of EDs as primary care providers for the population served.

Comparison of two different antiseptics regarding intracutaneous microbial load after preoperative skin cleansing in total knee and hip arthroplasties.

Periprosthetic infections (PPIs) are a serious concern in total knee and hip arthroplasty, and they have an increasing incidence. To prevent PPI, preoperative skin disinfection, as a key element of antisepsis, represents an important part of infection prevention. However, no specific antiseptic agent is endorsed by the relevant guidelines. The purpose of this retrospective, not randomized study was to investigate the difference in the residual bacteria load between an approved antiseptic with an alcohol-based solution with additional benzalkonium chloride (BAC) and an alcohol-based solution with additional octenidine dihydrochloride (OCT) at two different time periods. In 200 consecutive patients with total knee or hip arthroplasty, skin samples from the surgical sites were collected after skin disinfection with BAC (100 g solution contain: propan-2-ol 63.0 g, benzalkonium chloride 0.025 g) or OCT (100 g solution contain: octenidine dihydrochloride 0.1 g, propan-1-ol, 30.0 g, propan-2-ol 45.0 g) (100 patients per group). Following the separation of cutis and subcutis and its processing, culture was performed on different agar plates in aerobic and anaerobic environments. In the case of bacteria detection, the microbial identification was determined by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and the number of contaminated samples was compared between the groups. Additionally, multiple regression analysis was performed to examine the effect of the type of disinfectant, BMI, age, sex, rheumatoid arthritis, diabetes mellitus, skin disorders, smoking status, and localization of skin samples on positive bacteria detection. A total of 34 samples were positive for bacteria in the BAC group, while only 17 samples were positive in the OCT group (p = 0.005). Disinfectant type was the only significant parameter in the multiple regression analysis (p = 0.006). A significantly higher contamination rate of the subcutis was shown in the BAC group compared to the OCT group (19 vs. 9, p = 0,003). After the change from BAC to OCT in preoperative skin cleansing in the hip and knee areas, the number of positive cultures decreased by 50%, which might have been caused by a higher microbicidal activity of OCT. Therefore, the use of OCT in preoperative cleansing may reduce the risk of PPI in hip and knee surgery. Randomized controlled trials are required to confirm the effect and to evaluate if it reduces the risk of PPI.

Short proximal components in modular revision stems carry a higher risk for stem fractures.

INTRODUCTION: Fractures of modular hip revision stems are not uncommon. The current study examined implant-related factors on stem fracture. We hypothesised that in a modular stem the fracture risk is increased with the use of a short proximal implant component. MATERIALS AND METHODS: Anonymised data of all 32 patients in Switzerland with a Revitan modular hip system who had a stem fracture were obtained from the manufacturer. Implant and patient data were compared with all components implanted in Switzerland during the same time interval. RESULTS: Between 2002 and 2017, 4834 Revitan stems were implanted, of which 32 fractured. A smaller size of the proximal stem component was significantly associated with a higher fracture risk (p < 0.001). Compared with the control group, the proportion of male patients was higher among the fracture cases, patients were younger, and they had a higher body weight (p < 0.001, respectively). CONCLUSIONS: The present study suggests that small proximal stem components increase the load at the modular junction due to size and lack of bony support. Surgeons should therefore avoid short proximal components so that the mid-stem junction lies as distally as possible and the risk of fracture is minimised.

Meta-analysis of the efficacy of preoperative skin preparation with alcoholic chlorhexidine compared to povidone iodine in orthopedic surgery.

Preoperative skin preparation is an effective method to prevent surgical site infections (SSI). Alcoholic chlorhexidine (CHG) and povidone iodine (PV-I) are the most widely used antiseptic agents. This meta-analysis aims to determine their efficacy in reducing natural bacterial skin flora in clean orthopedic surgery. A systematic search was conducted through current literature up to June 2021 to identify clinical randomized trials that compared the efficacy of alcoholic chlorhexidine and povidone iodine in reducing bacterial skin colonization after preoperative skin preparation. A meta-analysis was conducted. Of 235 screened articles, 8 randomized controlled trials were included. The results of the meta-analysis demonstrate a significantly lower positive culture rate in the chlorhexidine group than in the povidone iodine group (RR = 0.53, 95% Cl: 0.32-0.88). The present data show the superiority of chlorhexidine in reducing the normal bacterial flora compared to povidone iodine in clean orthopedic surgery.

The different failure modes of the connecting elements of the modular hip arthroplasty revision stem Revitan.

INTRODUCTION: Fracture of the femoral stem is the cause of ~1 % of revisions after total hip arthroplasty. The risk increases intrinsically with modularity, whereby modularity is particularly useful in revision arthroplasty. We present 7 cases of failure of a specific modular, tapered, fluted, titanium alloy Revitan stem and analyse the different failure modes. METHODS: Retrospective review of all Revitan stems revised at our institutions due to implant failure and analysis of clinical presentation, diagnostic workup, and failure mode. The retrieved components were analyzed by optical and scanning electron microscopy. RESULTS: A total of 7 cases were included. There was a significant time lag between symptom onset and correct diagnosis. Conventional radiographs and low-dose CT scans (CT scout imaging) were decisive for diagnosis. All failures occurred at the level of the connection between the proximal component and the distal part of the stem. Three different failure modes were identified: loosening of the proximal component, fatigue fracture of the connection pin, and distal loosening of the connection pin. No alterations of the microstructure or deviation from manufacturing specifications regarding dimensions were observed. Failure was caused by mechanical overload. CONCLUSION: Conventional radiographs are the mainstay in identifying failed modular stems. Repeated radiographs and low-dose CT scans may be helpful additions. No single modification of the connection will address all possible failure modes. Modularity of revision stems offers advantages up until insertion of the definitive stem. Monoblock definitive stems might overcome the potential mechanical weaknesses of modularity and should be considered in relatively young, heavy and active patients.

Retroversion of the contralateral adult acetabulum after previous Perthes' disease.

Retroversion of the adult acetabulum following a previous Legg-Calvé-Perthes disease (LCPD) is found in 30-40% of the patients. It is known that in LCPD there may also be morphologic changes in the nonaffected controlateral acetabulum. We investigated the prevalence of retroversion of the contralateral acetabulum in a group of adult patients with a history of LCPD. We found this morphology in 11 out of 36 patients (31%). The aetiology and its relation to Perthes' disease are discussed.

Calcium dobesilate (Doxium®) in bone marrow edema syndrome and suspected osteonecrosis of the hip joint - A case series.

Osteonecrosis of the femoral head is a disease that leads to gradual degeneration of the hip joint causing immobility and a devastating impairment of quality of life. Early stage disease is characterised by a bone marrow edema of the proximal femur, a sight it shares with bone marrow edema syndrome. Although total hip arthroplasty offers quick symptom relief and functionally appealing results the treatment remains challenging, with its particularly young patients and considering limited non-invasive treatment options. We treated 6 patients with bone marrow edema in MRI and suspected osteonecrosis of the hip joint with calcium dobesilate, a vasoactive agent used in the treatment of diabetic retinopathy. We could demonstrate rapid symptom relief and concomitant disease remission on control MRI in early stage disease without any adverse events. Patients at advanced stages benefited in terms of pain reduction, but the treatment failed to halt disease progression. To the best of our knowledge, this is the first report of the therapeutic administration of calcium dobesilate in patients with bone marrow edema syndrome or osteonecrosis of the hip joint.

Septic arthritis of the knee due to Pantoea agglomerans: look for the thorn.

We report on a patient with septic arthritis of the knee with Pantoea agglomerans after a penetrating black locust thorn injury. Antibiotics alone or in combination with an arthroscopy may be insufficient for achieving source control. Accurate medical history and open debridement with a search for a thorn fragment are key to successful treatment.

Intraoperative loading of calcium phosphate-coated implants with gentamicin prevents experimental Staphylococcus aureus infection in vivo.

Orthopedic device-related infection (ODRI) is a potentially devastating complication arising from the colonization of the device with bacteria, such as Staphylococcus aureus. The aim of this study was to determine if intraoperative loading of a clinically approved calcium phosphate (CaP) coating with gentamicin can protect from ODRI in vivo. First, CaP-coated titanium aluminium niobium (TAN) discs were used to investigate the adsorption and release kinetics of gentamicin in vitro. Gentamicin loading and subsequent release from the coating were both rapid, with maximum loading occurring following one second of immersion, and >95% gentamicin released within 15 min in aqueous solution, respectively. Second, efficacy of the gentamicin-loaded CaP coating for preventing ODRI in vivo was investigated using a CaP-coated unicortical TAN screw implanted into the proximal tibia of skeletally mature female Wistar rats, following inoculation of the implant site with S. aureus. Gentamicin-loading prevented ODRI in 7/8 animals, whereas 9/9 of the non-gentamicin treated animals were infected after 7 days. In conclusion, gentamicin can be rapidly and simply loaded onto, and released from, CaP-based implant coatings, and this is an effective strategy for preventing peri-operative S. aureus-induced ODRI in vivo.

Fracture of a Femoral Revision Stem following a Technical Failure.

We report about a fracture of a modular, uncemented femoral revision stem (Zimmer, Revitan®) due to a not previously described intraoperative technical problem. During implantation, a small ring, part of the proximal part of the trial stem, was left on the distal part of the definite stem. Following this, the top screwcap of the proximal part of the definite stem could not be tightened properly. However, the stem was thought to be stable, and the situation left. Two and a half years later, the proximal part of the stem fractured and the situation became unstable. It is very useful to know about this ring and that it should always be removed, otherwise, there is possibility that it may be left on the definite distal part of the stem with the possibility of a later fracture.

Towards a better understanding of the aetiology of Legg-Calvé-Perthes' disease: acetabular retroversion may cause abnormal loading of dorsal femoral head-neck junction with restricted blood supply to the femoral epiphysis.

The most accepted part of the aetiology of Perthes' disease is an intermittent arterial occlusion. Many different reports now also suggest that some mechanical factor plays a role. In search of mechanical differences between normal hips and Perthes hips, many secondary morphologic differences of the proximal femur and the acetabulum are known. Recent research by the author has shown morphological changes of the acetabulum, independent of Perthes' disease in a large part of patients. In particular, retroversion of the acetabulum was found in a large part of adults who suffered from Perthes' disease as a child, and even in children who just developed Perthes' disease. The author suggest a relation of the two entities and hypotheses that due to the acetabular retroversion, there may be an intermittent, movement depending abnormal loading pressure on the dorsal femoral head-neck junction and the local blood vessels, which can lead to insufficient blood supply of the femoral epiphysis and to local necrosis, as these vessels are the only blood supply to the femoral epihysis in children.

Femoroacetabular impingement causes osteoarthritis of the hip by migration and micro-instability of the femoral head.

Femoroacetabular impingement is the condition whereby parts of the proximal femur mechanically collide with the acetabular rim leading to adjacent and contrecoup acetabular damage. Evidence is growing that at least for cam impingement, and perhaps less so for pincer impingement, there is a relation to the development of osteoarthritis. It has been demonstrated that surgery for impingement can improve function and decrease pain. Intuitively, it would then make sense that surgical intervention would prevent further degeneration. However, available literature to date cannot assure that it does. Therefore, the impingement itself seems not a sufficient cause to consistently cause osteoarthritis. For many years we have observed a phenomenon whereby the femoral head 'migrates' anteriorly and superiorly in the acetabulum in patients with cam impingement. The same, but less constant, can be observed in pincer impingement, where the head may migrate posteriorly and medially. Migration of the femoral head is known in the literature and seen as caused by, or as part of, osteoarthritis of the hip. We suggest that the migration is caused by the impingement, and that the femoral head wanders into the impingement-related area with cartilage damage. In cam impingement this may be anterolateral, in pincer impingement posteromedial. The effect must be a huge increase in compression forces, especially in cam impingement. The migration may even lead to, or be a sign of, micro-instability of the femoral head in the acetabulum, which may produce an increase in shear forces. We therefore hypothesise that impingement may lead to osteoarthritis by means of migration and the possible existence of micro-instability of the femoral head. Detecting and quantifying these phenomena seem of uttermost importance and may add a new dimension to conservative hip surgery.

Hip deformity in symptomatic adult Perthes' disease.

Only a limited number of patients that suffered from Legg-Calvé-Perthes' disease (LCPD) develop pain in early adulthood. Classical hinged abduction is well known and is thought to be responsible for secondary lateral insufficiency of the acetabulum, which may become painful. Another possible explanation, which was put forward more recently, is anterior femoroacetabular impingement. We collected information about the exact morphology of the proximal femur and the acetabulum of 15 hips in 15 young adults (mean age: 25.3 years) who had hip surgery consequent to childhood Perthes' disease in our hospital between 1974 and 2001. In addition to the well known lateral bulging of the femoral head, averaging 112% of the functional radius, we found an even larger anterior bulging, averaging 115% of the functional radius. The mean torsion of the femoral head was -3.6 degrees, which in fact corresponds to a retrotorsion. Retroversion of the acetabulum was found in at least 5 of the 15 hips in which the version could be adequately assessed (33%). Since any of the above deformities favours anterior femoroacetabular impingement and thus hinged flexion, this could well be a contributor to the development of the classic sequelae of LCPD and to the later development of osteoarthritis.

Partial resurfacing with varus osteotomy for an osteochondral defect of the femoral head.

Osteochondral defects of the femoral head represent a major challenge and various modern treatment options exist. We report a 16-year-old male with a large (3 x 3 cm) osteochondral defect of the femoral head that was treated with a partial resurfacing prosthesis combined with a high varus osteotomy, performed by surgical dislocation of the hip. Two years after surgery the patient was progressing well without complications.