Pediatric Lyme Disease Presenting as a Ruptured Popliteal Cyst: A Report of 3 Cases.

CASES: This case report describes 3 pediatric patients presenting with acute calf or knee pain, calf swelling, and a ruptured popliteal cyst diagnosed by magnetic resonance imaging. Lyme disease was serologically confirmed in each case. In all instances, treatment was delayed because of atypical presentation. All patients responded favorably after antibiotic therapy. CONCLUSION: The differential diagnosis of Lyme disease should be considered in the context of children presenting with atraumatic unilateral calf pain and a ruptured popliteal cyst. Otherwise, this unusual presentation could delay diagnosis or result in unnecessary surgical intervention, particularly in pediatric patients.

Extra-abdominal manifestations of retroperitoneal infection: a case of popliteal sinus secondary to duodenal ulcer.

Retroperitoneal abscesses can be gastrointestinal, urological or vascular in origin, and can spread via the retrofascial compartment through the psoas muscle to the lower limb. We describe the case of a 73-year-old woman with right knee pain for three weeks, a cellulitic right thigh and cholestatic liver function tests. A purulent sinus developed in the popliteal fossa and computed tomography of the abdomen revealed a right-sided retroperitoneal collection with gas, extending to the right pelvis and inguinal region. The popliteal fossa sinus and retroperitoneal collection were identified as a single pathology through computed tomography, magnetic resonance imaging and culture of identical organisms. At laparotomy, perforated duodenal ulcer disease was identified as the cause of the retroperitoneal abscess. Clinicians should seek to exclude retroperitoneal sources of infection in cases of lower leg infection, including perforated duodenal ulcer, caecal adenocarcinoma and appendicitis.

The prevalence of Baker cyst in relation to the arrangement pattern between the medial head of gastrocnemius tendon and the semimembranosus tendon.

PURPOSE: The purpose of this study was to investigate whether Baker cyst (BC) was related to the specific arrangement of the medial head of gastrocnemius tendon (MHGT) and the semimembranosus tendon (SMT). MATERIALS AND METHODS: Patients who underwent knee MRI with "Baker cyst" in PACS from August 2017 to February 2018 were included in this study. Patients who did not have BC in a knee MRI performed during the same period were included in the control group. A total 210 patients were selected for inclusion in this study. For the imaging analysis, the arrangement pattern between MHGT and SMT was classified into three types: type 1, concave; type 2, flat; and type 3, convex. When imaging analysis was performed, the amount of effusion, the presence of osteoarthritis, and major ligament and meniscal tears were also described. Univariate and multivariate logistic regression analyses were performed. Statistical significance was considered at p < 0.05. RESULTS: The frequency of types 1, 2, and 3 was statistically significant depending on the presence or absence of BC (p < 0.001). The frequency of type 3 was the highest in the presence of BC, while that of type 1 was the highest in the absence of BC. BC was more common in type 2 (OR = 2.54; 95% CI = 1.27-5.07) and type 3 (OR = 4.09; 95% CI = 1.88-8.89). CONCLUSION: BC is more likely to occur in patients with SMT having a convex shape for MHGT. KEY POINTS: • Based on axial image of MRI only, one can predict which patients are morphologically more prone to develop a Baker cyst. • On axial images of MRI, Baker cyst is more likely to occur in patients with semimembranosus tendon having a convex shape for medial head of gastrocnemius tendon. • Baker cyst is not associated with the amount of effusion, OA, or internal derangement.

Popliteal Skin Lesion due to Wear Disease in Total Knee Arthroplasty: A Case Report.

CASE: An 87-year-old woman presented with a popliteal skin lesion due to polyethylene wear 13 years following a left total knee arthroplasty. Excisional biopsy through a posterior approach was performed. Histology showed inflammation with granulomas and birefringent foreign body particles in the skin. Cultures remained negative, and revision knee arthroplasty was performed. CONCLUSIONS: A popliteal skin lesion due to polyethylene wear disease in total knee arthroplasty has not previously been described. Patients with an atypical inflammation of the skin with an underlying joint implant should be referred to an orthopaedic surgeon, and dermal biopsies should be checked for birefringent material. LEVEL OF EVIDENCE: Level V.

Pseudothrombophlebitis syndrome in a rheumatoid arthritis patient with swollen calf and persistent itching: a case report.

BACKGROUND: Baker's cyst is a benign lesion that results from degenerative or inflammatory diseases of the knee joint. When Baker's cyst ruptures, it may simulate deep vein thrombosis known as Pseudothrombophlebitis syndrome with calf pain, swelling and redness. Pseudothrombophlebitis syndrome without thrombus in popliteal veins has distinct treatment choice than deep vein thrombus. CASE PRESENTATION: In this report, we presented a 47 year-old male rheumatoid arthritis patient with complaints of redness, pain and swelling on his right calf. Pseudothrombophlebitis syndrome was diagnosed due to ruptured Baker's cyst. CONCLUSIONS: We used musculoskeletal ultrasound for both differential diagnosis and treatment of pseudothrombophlebitis syndrome. Ultrasonography revealed massive fluid collection within muscle layers. 280 cc inflammatory fluid was aspirated simultaneously. We also emphasized the importance of ultrasonography in diagnosis and treatment of Pseudothrombophlebitis syndrome with this report.

Popliteal (Baker's) Cysts in the Setting of Primary Knee Arthroplasty.

BACKGROUND: Popliteal (Baker's) Cysts are rare complications of knee arthroplasty. Enlargement, irritation, or rupture of the cyst can lead to significant pain, tightness, and tenderness. The literature regarding popliteal cysts occurring following knee arthroplasty is limited and does not report prevalence, natural history, and treatment of popliteal cyst in the setting of knee arthroplasty. METHODS: Following Institutional Review Board approval, 2,025 primary total and partial knee arthroplasties by four surgeons at one institution from 2011-2016 were reviewed for occurrence of popliteal cysts. Twelve cases occurring after arthroplasty were identified, including four unicompartmental knee arthroplasties and eight total knee arthroplasties. Demographic data were evaluated and symptoms, time of onset following arthroplasty, attempted treatment strategies, and success or failure of attempted treatments or interventions were recorded. RESULTS: The mean age of patients that presented with a popliteal cyst was 63.6 years old (range = 45 - 78 years). There were 5 males and 7 females. The mean BMI was 26.32 (range = 19.0 - 35.0). In 2,205 primary knee arthroplasties performed from 2011-2016 (including 175 partial and 1850 total), the prevalence of popliteal cysts following surgery was 0.6% (n=12). All popliteal cysts were discovered between six weeks and two years following surgery, with the majority occurring during the first year. Twenty-five percent (3/12) of patients presented with minimal symptoms. These were managed expectantly. Seventy-five percent (9/12) were symptomatic. One patient had only a diagnostic ultrasound, two patients underwent ultrasound-guided aspiration and steroid injection, three underwent simple aspiration. Two underwent surgical excision. One cyst ruptured. All cases went on to symptomatic resolution. There was no association with diabetes, smoking, or body mass index. A disproportionately high number (25% or 4/12) occurred in partial knee arthroplasty. CONCLUSION: While popliteal cysts following primary total knee arthroplasty are rare, they can become a persistent and even disabling problem for arthroplasty patients. Given the lack of formalized recommendations in the existing literature, we propose a treatment algorithm that has been successful in our clinic, including observation initially, ultrasound-guided injection/aspiration if symptomatic, and surgical excision as a last resort. LEVEL OF EVIDENCE: Level IV.

Demonstration of Lesions Produced by Cooled Radiofrequency Neurotomy for Chronic Osteoarthritic Knee Pain: A Case Presentation.

This case presentation demonstrates radiographic evidence of lesions created following cooled radiofrequency (cRF) neurotomy of the knee. A 67-year-old man presented with chronic left knee osteoarthritis, pain, and disability. After a failed trial of conservative treatments, the patient underwent diagnostic genicular nerve blocks and subsequent cRF neurotomy of the left knee. Shortly after cRF, magnetic resonance imaging (MRI) of the left knee was performed. On MRI, lesions created by cRF ablation were identified. The images presented in this case offer a visual explanation for the success of cRF in the treatment of knee osteoarthritis. LEVEL OF EVIDENCE: V.

[Features of pathological changes of fibro-cartilaginous tissue knee in patients with Baker cyst.]

Objective: Using magnetic resonance imaging (MRI) to evaluate the characteristics of pathological changes of fibro-cartilage of the knee in patients with Baker cyst, to assess the compliance of degrees of damage stages of osteoarthritis on a scale of Kellgren­Lawrence (K­L), and compare the results with the data of other researchers. Material and Methods: This study included patients (38­82 years) with a cyst Baker accidentally detected during ultrasound veins of the lower extremities. The subjects underwent a single knee MRI. MRI was made in three dimensions using 3D gradient-echo protocol. Independent radiologist evaluated the presence and severity of chondral defect osteophytosis, damage to the menisci and ligaments, intraosseous edema and subchondral cysts. The osteoarthritis stage of the knee were identified by X-ray performed in a standing position in the standard two projections, with K­L scale. Results: In this study, the results of a survey of 20 people, whose average age was 57.2 years. According to the radiological scale of K­L two patients were assigned to the stage 0 degree, 5 people to stage 1, 2, 4 each, and 3 ­ to stage 3. Synovitis of various severity was detected in 85% of the studies. Nineteen visualized the patellar cartilage damage, the condyles of the femur and tibia are most commonly affects the joint area. Among the most commonly injured ligament anterior cruciate ligament was determined ­ 9 (45%) patients in the same amount of detected intramedullary edema condyles femur and tibia. Eighteen subjects had at least one anomaly meniscus detectable by MRI, while in 11 (55%) persons were deviations, at least two or more regions of the knee examined. Conclusions: Our results suggest that not all visualized on MRI degenerative damage to intra fibro-cartilaginous tissue correlate positively with the stages of osteoarthritis of the knee, identified by standard radiographs and may not significantly affect the onset and progression of synovial cyst of the popliteal region.

Floating Tophi in a Baker Cyst Secondary to Gout: Ultrasound Features and Differential Diagnosis.

We report the case of a 36-year-old man with a recent diagnosis of gout, who presents with a fullness behind his right knee that fluctuates in size with time. An ultrasound revealed a Baker cyst that contained both large and punctate internal hyperechoic foci. Cyst aspiration revealed negatively birefringent crystals, which were consistent with gout.

Osteochondrolipoma Presenting as a Popliteal Cyst.

Here, we describe a popliteal mass that was initially misdiagnosed as a simple popliteal cyst, which finally turned out to be osteochondrolipoma. A 63-year-old housewife presented with sustained knee pain in association with a palpable mass on the popliteal fossa. The mass was in the posteromedial area and soft, non-tender, non-movable in the posteromedial area. Using plain radiography, the mass appeared as a round, soft tissue density lesion containing bony fragments. We performed an ultrasound-guided needle biopsy in conjunction with magnetic resonance imaging, followed by an open excisional biopsy. Microscopically, histological sections showed a lipoma with cartilaginous and osseous differentiation, finally diagnosed as osteochondrolipoma. In conclusion, popliteal masses are not always simple cysts, and the evaluation of masses in the popliteal fossa is always necessary.

Massive baker cyst resulting in tibial nerve compression neuropathy secondary to polyethylene wear disease.

Symptomatic synovial cyst formation is an infrequent, late complication after total knee arthroplasty. Most often, these cysts are found incidentally. However, rarely they may become larger leading to significant pain and disability. The formation of gigantic cysts necessitating revision knee surgery has been detailed in a few case reports. To the author's knowledge, this is the first report in the medical literature that describes peripheral neuropathy of the tibial nerve secondary to a massive Baker cyst after total knee replacement.

Osteochondrolipoma Presenting as a Popliteal Cyst

Here, we describe a popliteal mass that was initially misdiagnosed as a simple popliteal cyst, which finally turned out to be osteochondrolipoma. A 63-year-old housewife presented with sustained knee pain in association with a palpable mass on the popliteal fossa. The mass was in the posteromedial area and soft, non-tender, non-movable in the posteromedial area. Using plain radiography, the mass appeared as a round, soft tissue density lesion containing bony fragments. We performed an ultrasound-guided needle biopsy in conjunction with magnetic resonance imaging, followed by an open excisional biopsy. Microscopically, histological sections showed a lipoma with cartilaginous and osseous differentiation, finally diagnosed as osteochondrolipoma. In conclusion, popliteal masses are not always simple cysts, and the evaluation of masses in the popliteal fossa is always necessary.

The course of ultrasonographic abnormalities in knee osteoarthritis: 1 year follow up.

OBJECTIVE: Imaging of (peri)articular structures and inflammation with Ultrasonography (US) during the course of osteoarthritis (OA) might contribute to knowledge about early diagnosis of OA, prognosis and possibly the effect of disease modifying drugs. Our goal was to identify the prevalence of distinct patterns (stable vs fluctuating) in a set of US features in a cohort of patients receiving standard multimodal treatment for knee OA at T = 0, T = 3 months and T = 12 months. DESIGN: This was a prospective, explorative study including 55 patients fulfilling the American College of Rheumatology clinical criteria for knee OA. Six US features were investigated including: effusion, synovial proliferation, infrapatellar bursitis, meniscal protrusion, Baker's cyst and cartilage thickness at three time points during 1 year. A composite inflammatory score was composed. Overall prevalence was assessed as well as individual patterns which were appointed as stable or unstable. RESULTS: Inflammation like effusion and synovial hypertrophy does occur in over 40% of patients at some time in the year of follow up and shows a fluctuating pattern. Meniscal protrusion and Baker's cyst however are more stable features. CONCLUSIONS: Our study gives insight in the prevalence and course of US abnormalities in patients with knee OA and contributes to the knowledge on the possible role of this imaging modality in research.

[Popliteal cysts: etiologic and therapeutic approach]. / Kystes poplités: approches étiologique et thérapeutique.

In children and adults, a popliteal cyst frequently coexists with an intra-articular disorder of the knee. Its mode of presentation consists of a palpable mass at the level of the popliteal fossa. The cyst is a recess of the synovial cavity of the knee, often associated to a chronic effusion. In children, the etiology may be primary with a development directly from the medial gastrocnemius-semimembranous bursa. In adults, it is usually secondary to degenerative or inflammatory disease of the knee. A communication between the intraarticular space and the cystic cavity can be often found. The aim of this study is to review epidemiology, pathogenesis, symptomatology, diagnosis and treatment options.

Prevalence of Baker's cyst in patients with knee pain: an ultrasonographic study.

The objectives of this study are to investigate the prevalence of Baker's cyst (BC) in patients with knee pain, and to assess the correlation between BC and severity of osteophytes and joint effusion. A retrospective study was conducted on a group of patients with knee pain referred to our outpatient clinic for ultrasonography of the knee between January 2010 and February 2011. Patients underwent an ultrasonographic exam of the knees to assess the presence of marginal femorotibial osteophytosis, joint effusion and BC. A dichotomous score was assigned to each item (1 present, 0 absent) and severity of US signs of osteoarthritis and joint effusion were also graded semiquantitatively. Collected data were processed using logistic regression analysis to evaluate the correlation between degree of osteophytosis and joint effusion and BC. Patients affected by inflammatory joint conditions or with history of joint surgery or recent trauma were excluded. A total of 399 patients with knee pain were studied (299 women), in the age range 18-89 years (mean 56.2, SD 16.3 years). 293 patients (73.4%) showed sonographic features of osteoarthritis and 251 (62.9%) joint effusion. BC was found in 102 patients (25.8%) together with a positive association with sonographic features of osteoarthritis and joint effusion. Our data show a prevalence of BC of 25.8% in a population of patients with knee pain, and suggest that BC is positively related to osteoarthritis and joint effusion. Ultrasonographic examination of knee is worthwhile in patients with painful osteoarthritis or evidence of effusion.

Ultrasonographic evaluation in symptomatic knee osteoarthritis: clinical and radiological correlation.

AIM: To explore the relationship among clinical, radiological and ultrasonographical findings in knee osteoarthritis (OA). METHOD: Sixty-one patients (122 knees) with knee OA were enrolled. Patients' knees were classified into two groups according to symptom severity. Group I consisted of 61 more symptomatic knees and Group II comprised 61 less symptomatic knees. Subjects were clinically assessed for pain and functional status by using a visual analog scale and the Western Ontario and McMaster Universities Arthritis Index (WOMAC), respectively. Knee radiographs were evaluated by using the Kellgren-Lawrence (K-L) grading system. All knees were also evaluated ultrasonographically for meniscal bulging, distal femoral cartilage thickness, cartilage grading and also for the presence of effusion, Baker's cyst and so on. RESULTS: Baker's cyst and joint effusion were observed more in Group I when compared with Group II. Positive correlations were found between meniscal bulging and all WOMAC scores (all P < 0.05). K-L grades of the patients were also positively correlated with WOMAC scores (all P < 0.05). Meniscal bulging measurements and K-L grades were positively correlated (P < 0.001). There was a negative correlation between cartilage grades and cartilage thickness measurements (all P < 0.001). CONCLUSIONS: We found that joint space narrowing seemed to be associated with meniscal bulging. Moreover, increased meniscal bulging and presence of Baker's cyst/joint effusion were associated with worse pain or poorer function.

Ultrasound monitoring of the treatment of clinically significant knee osteoarthritis.

OBJECTIVES: The study presented an ultrasound (US) monitoring of treatment as a new imaging US method with the results of therapy of clinically significant knee osteoarthritis. BACKGROUND: X-ray is widely used for knee osteoarthritis classification, which does not involve the evaluation of the soft tissue. High frequency and high resolution US of joints (arthrosonography, echoarthrography) assess not only morphologic but also functional changes in the knee joint. METHODS: In the prospective study, 110 patients with clinically significant knee osteoarthritis were treated non-operative. US examination and US monitoring of therapy was performed during 24 weeks therapy period. A remission of pathomorphologic (marginal osteofytes) and pathophysiologic (effusion in anterior knee and Baker´s cyst) attributes were evaluated according the US classification. RESULTS: Pathomorphologic attributes changes showed a static state, without remission or progression. Pathophysiologic attributes changes showed a remission during the study period. The highest remission was in the first three weeks, 60 % anterior knee effusion and 62 % Baker´s cyst. At the end of study, no changes from the initial US grade was observed in 16 % of effusion in anterior knee and 22 % of Baker´s cyst. Therapeutic resistant Baker´s cyst was present at the end of study in 36 %. CONCLUSION: We demonstrated a new method - US monitoring of therapy, which can objectivize the efficiency of treatment of clinically significant knee osteoarthritis. We would recommend US monitoring of therapy for the routine use in orthopedic clinical praxis (Tab. 6, Graph 3, Fig. 3, Ref. 15).