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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., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/B801)., (Copyright © 2022 by The Journal of Bone and Joint Surgery, Incorporated.)

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.

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.

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.

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.

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., (Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

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.

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 Kellgren–Lawrence (K–L), and compare the results with the data of other researchers., Material and Methods: This study included patients (38–82 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 K–L 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 K–L 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.

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.

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.

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.

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., (Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

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., (© 2013 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.)

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.

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.

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).

Background: Combining different therapies, physical therapy agents, pharmacological and physical therapies, generally produces better outcomes for symptoms of knee osteoarthritis (OA) than do isolated therapies., Aim: To demonstrate if horizontal therapy (HT) and aspiration alone and corticosteroid injection alone or in combination determine pain relief and functional improvement in a group of patients with knee OA complicated with Baker's cyst (BC)., Design: We designed a randomized controlled trial (RCT)., Setting: Outpatients., Population: Sixty patients with a knee OA and diagnosis of BC confirmed by means of standard ultrasound (US) evaluation., Methods: The trial was conducted as a randomized, controlled trial. Patients who satisfied the inclusion criteria were randomized to either the US-guided (Ultrasound Guided BC aspiration and corticosteroid injection group (Group A), the Horizontal Therapy group (Group B) or the US-guided BC aspiration and corticosteroid injection plus Horizontal therapy group (Group C). Outcome measures included: 1) pain reduction as measured by visual analogue scale (VAS); 2) functional improvement, as measured by WOMAC; and 3) US evaluation at baseline (T0), at one (T1) and four (T2) weeks follow-up., Results: A total of 60 patients were randomized into group A (N.=20), group B (N.=20) or Group C (N.=20). Patients in group A and in group C, but not those in group B maintained lower pain level at T2 than at baseline, with significant lower VAS values in Group C. As regards US measurements, the maximum axial area did not change as a consequence of the treatment in any of the three groups (P=0.259). Contrarily, sagittal area measurements were influenced by time (P<0.01)., Conclusion: Our results show that the group with the best performance for pain, functionality and dimension of BC was that in which combined use was made of horizontal and corticosteroid injection therapies., Clinical Rehabilitation Impact: In this study we want to demonstrate the effectiveness of Horizontal Therapy in the treatment of knee OA complicated by BC.

The incidence of pseudotumor formation has been reported to be 1% in patients with metal-on-metal resurfacing arthroplasties. This complication is not exclusive to these patients. We report a case of pseudotumor formation secondary to femoral head-neck corrosion after a metal-on-polyethylene uncemented total hip arthroplasty., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Despite increasing knowledge of etiopathogenesis, therapy, and recurrence rate of popliteal cysts, they nevertheless occasionally represent clinical problems. We report the case of a 58-year-old rheumatoid arthritis patient in whom a giant recurrent cyst developed very shortly after primary excision. Reports of such large popliteal cysts are rare and very few cases were reported in rheumatoid arthritis patients. Moreover, no such giant recurrent cysts formed so shortly after primary excision. Thus, its occurrence may be partially ascribed to the specific dynamics of fluid flows caused by the absence of a valve-like mechanism. With regard to treatment, it appears that synovectomy may reduce the production of synovial fluid, but reinforcement of the thin tissue with capsuloplasty may also be important. Immobilization is necessary so that initiation of the healing process is not disturbed.

Post-steroid septic arthritis can be treated with irrigation pump assisted arthroscopic synovectomy. The high-intra-articular fluid pressures can force the pyogenic fluid into a pre-existing Baker's cyst. The cyst can rupture and with the pre-existing steroid induced immune-suppression, the calf abscess will be hard to control. Therefore, thorough investigation with an ultrasound-guided aspiration followed by an early drainage of the collection is warranted and mandatory. Close monitoring for the development of a deep thrombosis of the popliteal vein is required.

This study aimed to determine the ultrasonographic prevalence of Baker's cysts in knees with chronic osteoarthritic pain and investigate for cysts correlates and relationships with scintigraphically established synovitis. Consecutive patients with chronic osteoarthritic knee pain underwent clinical examination, X-rays, ultrasonography and early-phase bone scintigraphy. Eighty-nine Baker's cysts were detected in 328 knees with chronic osteoarthritic pain (27%), whereas one cyst was identified among the 54 non-osteoarthritic knees (2%, P<0.001). Baker's cysts were detected in 72/195 (37%) patients with knee osteoarthritis. Abnormal and intense tracer accumulation in early-phase bone scintigraphy were significantly more frequent in osteoarthritic knees with Baker's cysts (97 and 56%, respectively), than in those without (89 and 40%, respectively, P<0.05 for both). Clinical and radiographic variables could not predict the presence of those cysts. Baker's cysts are a common ultrasonographic finding in knees with chronic osteoarthritic pain and are associated with synovial inflammation and its grade.

A 22-year-old male underwent an arthroscopic meniscal repair, using meniscal arrows, due to bucket-handle medial meniscus tear. Magnetic resonance images (MRI) at 3 years revealed a large parameniscal cyst protruding into the extra-capsular popliteal space. Arthroscopic partial cystectomy, removing only the intra-articular portion of the cyst was performed, leaving the extra-articular part of the cyst. Sixteen months postoperatively MRI revealed no cyst remnants, and the patient was free of symptoms.

Cystic adventitial disease is a rare non-atheromatous cause of popliteal artery disease. We report a case of a 54-year-old patient with claudication of the right calf caused by cystic adventitial disease. Intra-operatively, a communication between the adventitia and the knee joint was identified. Connections between the adventitial cyst and the nearby joint have been reported in the literature that support the developmental theory. This theory suggests that cystic adventitial disease is a developmental manifestation of mucin-secreting cells derived from the mesenchyme of the adjacent joint. This case is the first, to our knowledge, in which a communication between joint and adventitia has been clearly documented by operative findings.

Popliteal cyst is a rare finding after total knee arthroplasty (TKA), but when present, it might indicate a malfunction of the TKA related to generation of wear-particles, or loosening. We present a case of a multilobulated popliteal cyst developing in a patient 8 years after primary TKA. The cyst was associated with a mechanical prosthetic loosening. The primary complaint of the patient was pain in the posterior region of the knee. A two-stage procedure consisting of cyst excision at first, followed after 5 months by a revision TKA was performed. Intraoperatively, a darkish, multilobulated cyst with a well-defined thick wall filled with fluid containing polyethylene debris, communicating with the knee joint was found. After 3 years of follow-up, the patient was satisfied and walked without the support of a cane. The patient presented a satisfactory knee range of motion. Clinical, radiological and ultrasound investigations ruled out popliteal cyst recurrence. A dissecting popliteal cyst associated with a failed TKA should be excised because it contains polyethylene debris that constitutes an induced factor for prosthetic loosening. A two-stage procedure with quite a long time in-between, as presented in this paper, can be a useful alternative to manage such a problem, in particular in very old patients associated with other medical problems.

Lyme disease is the most common tick-borne disease in North America. Our review of the literature found few reports of Lyme disease presented in the orthopaedic literature. However, Lyme disease presenting as a popliteal cyst, with or without rupture, is rarely reported. We present 4 cases of Lyme disease that initially presented to our pediatric orthopaedic clinic for treatment of a popliteal cyst. The early diagnosis and treatment of Lyme disease may help prevent the often-devastating long-term sequelae of Lyme disease. The goal of this article is to increase the awareness of Lyme disease presenting in children as a popliteal cyst.

A popliteal cyst, originally called Baker's cyst, is a synovial fluid-filled mass located in the popliteal fossa. The most common synovial popliteal cyst is considered to be a distension of the bursa located beneath the medial head of the gastrocnemius muscle. Usually, in an adult patient, an underlying intra-articular disorder is present. In children, the cyst can be isolated and the knee joint normal. The anatomy, etiopathogenesis, clinical presentation, differential diagnosis, imaging and treatment modalities of the popliteal cyst are presented. The authors try to answer some questions dealing with this condition. Is the cyst isolated, can it be treated as such, is its origin always well-defined and does surgical excision provide a permanent cure?

Background: This prospective study was designed to investigate the aetiology of popliteal (Baker's) cysts., Methods: Some 426 legs in 312 individuals were investigated with ultrasonography for the presence of a popliteal cyst. Participants included healthy volunteers, patients with a painful knee, and a group of patients with signs and symptoms of deep vein thrombosis (DVT). The location, thickness and content of all cysts were recorded. In addition, the popliteal fossa was dissected in four cadaver knees., Results: The prevalence of popliteal cyst increased with age and was significantly higher in those aged over 50 years (P < 0.001). Compared with controls (incidence 3.0 per cent), cysts were more common in patients with DVT symptoms (9.5 per cent; P = 0.141) and those with painful knees (19.8 per cent; P < 0.001). All cysts were located in the posteromedial aspect of the popliteal fossa; the majority extended between the deep fascia and the medial head of the gastrocnemius muscle. At this level an area without external support of the posterior capsule was identified between the two expansions of the semimembranosus muscle from the medial side (the oblique popliteal ligament and the expansion over the popliteus muscle) and the posterior cruciate ligament from the lateral side. This area was also located in the knee dissections. No association was found between popliteal cyst and acute DVT., Conclusion: Popliteal cysts are relatively common in patients over 50 years old with a painful knee or with signs and symptoms of DVT. They form in the posteromedial popliteal fossa because the synovial capsule does not provide anatomical support in this region., (Copyright (c) 2004 British Journal of Surgery Society Ltd)

We describe a surgical treatment for popliteal cyst in a 41-year-old woman affected by diffuse pigmented villonodular synovitis (PVNS) of the knee with extra-articular spreading. The treatment consists of an arthroscopic synoviectomy followed immediately by an open removal of the cyst. At 28-month follow-up, the patient is asymptomatic and no evidence of recurrence of PVNS has been seen. We believe that this double surgical approach may reduce the probability of recurrence of PVNS.

We present a case exhibiting persistent joint effusion and formation of a gigantic popliteal synovial cyst 8 years after total knee joint arthroplasty. Assessment using flow cytometry revealed that both joint and cyst fluid contained abundant macrophage-phagocytosing wear particles. This finding indicates that wear particles participated in formation of the cyst through the communication between the joint cavity and cyst. Intraoperatively, prominent villous synovial proliferation was observed in both the joint and cyst, and delamination failure of the polyethylene insert was identified. Because no evidence of prosthetic loosening was found, only polyethylene insert revision and synovectomy were undertaken, resulting in a successful outcome. This case suggests that synovial cyst formation in popliteal lesions might represent a sign of wear-particle generation after total knee joint arthroplasty.

This report documents the first case of a popliteal cyst in a knee with failed unicompartmental knee arthroplasty (UKA). The cyst was treated successfully with the creation of a small communication hole between the posteromedial compartment and the popliteal cyst under direct arthroscopic visualization. This was followed by the replacement of a worn polyethylene insert via a small arthrotomy. Three months later, the popliteal mass had disappeared. This case suggests that a dissecting popliteal cyst may occur after UKA as one of the signs of a malfunction. It also suggests that treatment should be directed toward the joint and not the cyst itself.

Dissecting popliteal cyst is an uncommon complication after total knee arthroplasty, occurring mainly as a result of either rheumatoid arthritis or a malfunctioning knee prosthesis. Its association with a failed metal-backed patellar component has not been reported since the introduction of the resurfacing of the patella with this kind of design in 1980. We present a case of a late fracture-dislocation of the metal part of the patellar component that migrated to the posterior popliteal fossa, resulting in a cystic mass formation caused by a foreign body granuloma. The patient was treated successfully with a 2-stage operation: first, revision of the total knee arthroplasty and, second, excision of the cyst. The patient had a pain-free functional knee 7 years after surgery, with no recurrence of the symptoms or the popliteal cyst., (Copyright 2002, Elsevier Science (USA).)

Baker's (Popliteal) cysts are frequently encountered on cross-sectional imaging of the knee. These consist of enlarged gastrocnemius semimembranosus bursa which typically communicate with the knee. They may be imaged with a variety of techniques including arthopgraphy, CT, ultrasound and MRI, with the latter two being more commonly used. Examples of bursa imaged with all of the above techniques are demonstrated in the essay, as well as variance of normal appearance and pathological entities including ruptured bursa, abnormally positioned bursa, osteochondromatosis, septic complications of the bursa and pigmented villonodular synovitis.

The Baker's cyst is a distension of the bursa subtendinea and is caused by noninfectious knee effusion secondary to arthrosis, meniscal tears, trauma, rheumatoid arthritis, gout, or any other form of sinovitis, like rheumatoid arthritis. An infected popliteal cyst is much less common; tuberculous arthritis is exceptional, in fact only four cases are described in literature. Herein we describe an additional tbc case of a 51 years old men, who has been initially treated with cytostatic and corticosteroid agents, for a suspected rheumatoid arthritis. The review of the literature suggests the importance of a correct approach to the diagnosis, based on the analysis and culture of the synovial fluid, because delays latency of effective antibiotic therapy can result in permanent joint damage that invalidate the patients.

Purpose: To define the epidemiology and clinical features of Behçet's disease, giving special attention to unusual forms., Methods: We retrospectively reviewed the medical records of 309 cases with joint manifestations among 450 cases of Behçet's disease seen over a 20-year period who met the International Study Group of Behçet's disease criteria., Results: Joint manifestations were present in 68.3% and were inaugural in 34.5%. The knee and ankles were the joints most commonly affected. Monoarthritis, oligoarthritis and polyarthritis were seen respectively in 12, 13.5 and 19.8%. Sacroiliitis is observed in 6%. Unusual forms included destructive polyarthritis (two cases), popliteal cyst (two cases), myositis (two cases) and ankylosing spondylitis (two cases)., Conclusion: Joint manifestations are common in Behçet's disease. They are frequently associated with erythema nodosum and necrotic pseudofolliculitis. Polyarthritis is not rare. Their unusual forms deserve to be known.

We report a case of total knee arthroplasty (TKA) failure presenting initially as a large popliteal cyst without bony destruction in a 66-year-old woman. A foreign body gigantocellular inflammatory reaction against polyethylene wear particles was found on histology. The size of the cyst and the absence of bony destruction can be due to an exclusive early intramuscular granulomatous reaction. Progressive loosening of the femoral component and narrowing of the joint space heralded the TKA failure.

Objective: To review the epidemiology, clinical presentation, pathogenesis, imaging, differential diagnosis, complications, and treatment of popliteal cysts., Methods: References were taken from MEDLINE from 1985 to 1998 under the subject "Popliteal Cyst" with subheadings of Radiography, Ultrasonography, and Radionuclide Imaging. Other pertinent references were used. Childhood cysts were excluded., Results: Depending on the studied population and the imaging technique, 5% to 32% of knee problems may have these cysts, with 2 age-incidence peaks of 4 to 7 years and 35 to 70 years. In older patients there is usually coexistent joint pathology. Symptoms may arise in the popliteal fossa from the cyst itself or be dominated by knee pain from coexisting knee pathology. Many cysts are asymptomatic. Physical examination will miss one half of these cysts. Pathogenesis depends on the connection between the joint and bursa, with a valvelike effect allowing passage of fluid from the joint into the bursa with subsequent distention producing these cysts. Some bursae have no such joint-bursal communication, and the cysts arise primarily as bursitis of the gastrocnemio-semimembranosus bursa. Imaging is performed by plain x-ray, ultrasound, arthrography, computerized axial tomography, magnetic resonance imaging, or nuclear scan; sonography is the method of choice. Complicated cysts with extension or rupture into the calf mimic phlebitis, an important differential diagnosis. Asymptomatic cysts found incidentally need no treatment; most symptomatic cysts respond to intra-articular corticosteroid injections. Surgical excision is rarely necessary., Conclusions and Relevance: Popliteal cysts are fairly common, may not be found on physical examination, require imaging (preferably sonography) to be identified, mimic phlebitis when extending into the calf, and often respond to intra-articular steroid or, rarely, surgical resection., (Copyright 2001 by W.B. Saunders Company)

A symptomatic popliteal cyst after total knee arthroplasty (TKA) is rare, occurring most frequently as a result of intra-articular knee pathology. We present a case of a large dissecting popliteal cyst 7 years after TKA with symptoms of severe calf pain and functional disability. The symptomatic cyst was excised completely in a first-stage operation, and the severely worn TKA was corrected by a second-stage surgical procedure. The patient in this report was pain free and had satisfactory range of knee motion 5 years after the index revision TKA, without recurrence of effusion or popliteal cyst formation.