Association of complicated Baker's cysts with knee pathologies as compared to simple Baker's cysts.

Baker's cysts (BCs) are known to be associated with intra-articular pathologies. BCs can be classified into 2 types: simple and complicated. Although some studies have focused on BC using magnetic resonance imaging (MRI), which is the gold standard examination, no study has compared knee MRI features in patients with simple and complicated BCs. To assess the relationship between the type of BC (simple vs complicated) and other knee pathologies using MRI. Seventy patients who underwent knee MRI examination due to symptomatic knee were retrospectively recruited from April 2011 to April 2021 at a single hospital. In the knee MRI images, the following were assessed: type (simple or complicated), morphology, volume of BCs, thickness of the suprapatellar recess, presence of synovial proliferation of the suprapatellar recess, grade of knee joint effusion, presence of meniscal tear, and extent of meniscal extrusion. The patients were classified into 2 groups according to the type of BC: simple BC and complicated BC. The differences between the 2 groups were evaluated for all variables. Finally, 52 patients were included in this study, 15 were classified as "simple BC" group and 37 as "complicated BC" group. The volume of complicated BC (median: 4.6, interquartile range - IQR: 1.6-12.4) was significantly greater than that of simple BC (median: 0.7, IQR: 0.3-3.7; P = .007). The presence of synovial proliferation in the suprapatellar recess was significantly higher in complicated BC (91.9%) than that in simple BC (46.7%; P = .001). The thickness of the suprapatellar recess was significantly greater in complicated BC (median: 7.5, IQR: 5.8-10.7) than that in simple BC (median: 4.3, IQR: 2.3-7.6; P = .020). The medial meniscus extrusion was greater in complicated BC (median: 4.1, IQR: 2.8-5.1) than that in simple BC (median: 2.5, IQR: 1.8-4.4; P = .037). After adjusting these P-values using the Holm method, only the presence of synovial proliferation in the suprapatellar recess remained significant (P = .010). Using knee MRI images, we demonstrated that complicated BCs are more associated with intra-articular pathologies than simple BCs; such as cyst volume, amount of the knee joint effusion, synovial proliferation and medial meniscal extrusion. Among them, the presence of synovial proliferation was the most significant factor associated with complicated BCs.

Ruptured Baker Cyst on 18 F-FDG PET/CT.

ABSTRACT: A 78-year-old woman with diffuse large B-cell lymphoma was referred for an 18 F-FDG PET/CT to evaluate therapy response after 6 cycles of R-mini-CHOP. A new 18 F-FDG accumulation was noticed medial in the upper part of the right lower leg, spreading along the medial head of the gastrocnemius muscle. The shaft-bow-looking curvature, arch sign, of 18 F-FDG revealed a fluid collection on CT. This typical pattern and its specific location are indicative of a ruptured Baker's cyst. It can manifest in 1 or both legs.

Atypical Calf Cyst Treated With Doxycycline Sclerotherapy: A Case Report.

ABSTRACT: There are many types of cysts in the leg; the most common is a popliteal (Baker's) cyst. This occurs when synovial fluid fills the tissue plane between the medial head of the gastrocnemius and the semimembranosus muscle and is often associated with intraarticular knee pathology. Treatment for various types of cysts includes aspiration with or without fenestration, injections with corticosteroids, dextrose, or various sclerosing agents, and surgical excision. This case describes a 58-yr-old man with a large cyst measuring 14.7 × 2.7 × 3.1 cm in size in the lateral calf, within the lateral gastrocnemius, with atypical size and location for a calf cyst. Computed tomography arthrogram showed intraarticular communication with the knee. The cyst recurred after two aspirations and injections with 25% dextrose/lidocaine. Aspiration and injection with doxycycline resulted in temporary relief followed by recurrence. Complete cyst resolution occurred after final aspiration without injectate. The cyst was likely synovial based on location, intraarticular communication, and fluid analysis. We suspect that complete resolution may have been due to repeated aspiration and injection, essentially performing longitudinal cyst fenestration, with possible contribution from doxycycline injection. Further study of intracyst doxycycline injection with reaspiration after 10 mins for treatment of refractory cysts may be warranted.

Double posteromedial portals versus single posteromedial portal for arthroscopic management of popliteal cysts.

BACKGROUND: As a common disease in orthopedic clinics, popliteal cysts often coexist with intra-articular lesions. Compared with traditional open surgery, arthroscopic treatment of popliteal cysts is less traumatic, and intra-articular lesions can be treated. The 'one-way valve' mechanism of the popliteal cyst can be removed by expanding the communication between the articular cavity and the cyst to avoid cyst recurrence. In terms of arthroscopic techniques, the comparison of clinical effects between the double posteromedial portal (DPP) and single posteromedial portal (SPP) has rarely been studied. The purpose of this retrospective study was to compare the clinical effects of DPP and SPP. METHODS: A total of 46 consecutive patients with symptomatic popliteal cysts who underwent arthroscopic treatment were included in this study and followed for approximately 1 year. All patients were divided into two groups according to the arthroscopic portals (DPP group and SPP group). The cyst size, Lysholm score and Rauschening-Lindgren (R-L) grade were evaluated before the operation for all patients, and the intra-articular lesions, operative time and complications were recorded after operation. At the last follow-up, the Lysholm score and R-L grade were recorded, and magnetic resonance imaging was used to evaluate the outcome of the cyst. The clinical data of the two groups was statistically compared and analyzed. RESULTS: There were no significant differences in preoperative cyst size, Lysholm score or R-L grade between the two groups (P > 0.05). The operation time of the DPP group (67.52 ± 18.23 min) was longer than that of the SPP group (55.95 ± 16.40 min) (P = 0.030), but the recurrence rate of cysts in the DPP group (0%) was obviously lower than that in the SPP group (19.0%) (P = 0.046). There were no significant differences in the Lysholm score, R-L grade or complication rate between the two groups at the last follow-up (P > 0.05). CONCLUSION: Arthroscopic treatment of popliteal cysts using double posteromedial portals was a safe and effective surgical method. TRIAL REGISTRATION: ChiCTR, ChiCTR2200060115. Registered 19 May 2022, https://www.chictr.org.cn/showproj.html?proj=133199.

Risk factors for residual popliteal cyst after arthroscopic decompression and cystectomy: Associated with degenerative cartilage lesions.

BACKGROUND: In previous studies, good results have been reported after arthroscopic treatment of popliteal cysts and concomitant intra-articular pathology. However, only a few studies have reported the associated factors with residual popliteal cysts. The aim of this study was to examine the clinical and radiographic outcomes and investigate the factors associated with the recurrence of popliteal cyst after arthroscopic cyst decompression and cyst wall resection. HYPOTHESIS: The authors hypothesized that residual popliteal cyst after arthroscopic decompression and cystectomy would be associated with degenerative cartilage lesions. PATIENTS AND METHODS: From December 2010 to December 2018, 54 patients with popliteal cysts were treated with arthroscopic decompression and cyst wall resection through an additional posteromedial cystic portal. Magnetic resonance imaging (MRI) or ultrasonography was used to observe whether the popliteal cyst had disappeared or decreased. The maximum diameter of the popliteal cyst was measured after surgery. The patients were classified into the disappeared and reduced groups according to the treatment outcome. Age, sex, symptom duration, preoperative degenerative changes based on the Kellgren-Lawrence (K-L) grade, cartilage lesions according to the International Cartilage Repair Society (ICRS) grades, synovitis, functional outcomes, and associated intra-articular lesions were compared between the two groups. The functional outcome was evaluated on the basis of the Rauschning and Lindgren knee score. The study included 22 men and 32 women, with mean age of 49.6 years (range, 5-82 years). According to the ICRS grade system, 28 (51.8%) patients had grade 0 to II, 26 (48.2%) patients had grade III to IV. RESULTS: Follow-up radiographic evaluation revealed that the cyst had completely disappeared in 20 patients (37%) and reduced in size in 34 (63%). The mean cyst size was decreased significantly from 5.7cm (range, 1.7-15cm) to 1.7cm (range, 0-6.4cm), and the Rauschning and Lindgren knee score showed improved clinical features in all the patients. Between the disappeared and reduced groups, the presence of degenerative cartilage lesions (p=0.022, odds ratio 8.702, 95% confidence interval: 1.368-55.362) showed statistically significant differences. DISCUSSION: Through the posteromedial cystic portal, cysts were completely removed in approximately 40% of patients, and the size was reduced in 60% of patients. Presence of degenerative cartilage lesion represents an associated risk factor for residual popliteal cyst. These findings could be helpful in ensuring explaining poor prognostic factors. LEVEL OF EVIDENCE: IIIb; retrospective cohort study.

Diagnostic accuracy of ultrasound for the assessment of Baker's cysts: a meta-analysis.

BACKGROUND: Baker's cyst is the most common cystic disease of the knee, and a fast and accurate diagnosis of Baker's cyst is essential for a better management. Ultrasound is a rapid, portable, widely available, inexpensive and noninvasive imaging modality. However, the diagnostic accuracy of ultrasound on Baker's cyst still remains undetermined. We conducted the first meta-analysis to comprehensively assess the accuracy of ultrasound for the detection of Baker's cyst. METHODS: PubMed, Embase and Web of Science were searched from inception to July 14, 2022, without language restrictions. Studies providing cross-tabulations of ultrasound versus pathology (gold standard) or MRI (standard imaging technique) for diagnosis of Baker's cyst were included. Indicators for the diagnostic accuracy of ultrasound, including sensitivity, specificity and area under the curve, were calculated using a bivariate model. Sensitivity analysis was conducted to evaluate the heterogeneity and robustness of the results. RESULTS: A total of 13 studies with 1,011 subjects (mean age 32.2 years; men 53.5%) met the inclusion criteria. The pooled sensitivity, specificity and area under the curve of ultrasound for diagnosis of Baker's cyst, compared with pathology, were 0.97 (95% confidence intervals: 0.73-1.00), 1.00 (0.98-1.00) and 1.00 (0.99-1.00), respectively. The pooled estimates of ultrasound versus MRI were 0.94 (0.87-0.98) for sensitivity, 1.00 (0.83-1.00) for specificity and 0.97 (0.95-0.98) for area under the curve. Sensitivity analysis did not change the results materially. CONCLUSION: Ultrasound shows excellent diagnostic accuracy for the assessment of Baker's cyst and provides similar diagnostic information (absent or present) compared to MRI. Because of its advantages of low cost, portability and accessibility, ultrasound is likely to be a choice of imaging technique for screening Baker's cyst in clinical and population settings as well as in follow-ups.

Popliteal cysts are not a risk factor for lower extremity deep vein thrombosis.

BACKGROUND: Popliteal cysts (PC) result from distension of the gastrocnemio-semimembranosous bursa. Published reports indicate coincident PC and deep vein thrombosis (DVT). Whether the presence of PC increase the risk of deep vein thrombosis (DVT) remains unclear. METHODS: Lower extremity venous Duplex ultrasound (DUS) reports were evaluated across the Mayo Clinic Enterprise (Rochester, Minnesota, Jacksonville, Florida, Scottsdale, Arizona, and the Mayo Clinic Health System) in patients ≥ 18 years of age. Natural language processing (NLP) algorithms were created and validated to identify acute lower extremity DVT and PC from these reports. To determine whether there is a link between PC and lower extremity DVT, the frequency of PC among cases (ultrasounds with acute DVT) were compared to controls (ultrasounds without acute DVT). RESULTS: A total of 357,703 lower extremities venous DUS were performed in 237,052 patients (mean age 63.3 ± 16.6, 54.4% were female) between 1992 and 2021. Acute DVT was identified in 32,572 (9.1%) DUS, and PC in 32,448 (9.1%). PC were seen in a lower frequency (8.0%) of ultrasounds with acute DVT than those without (9.2%) acute DVT (OR: 0.85, 95% CI: 0.82 to 0.89, p < 0.001). In a multivariate logistic regression model after adjusting for age, sex, and race, PCs were not positively associated with acute DVT (adjusted OR: 0.84, 95% CI: 0.81 to 0.88). CONCLUSIONS: PC are an incidental finding or an alternative diagnosis on lower extremity venous DUS, a finding that increases significantly with age. PC were not a risk factor in the development of lower extremity DVT.

Comparison of arthroscopic internal drainage and open excision for the treatment of popliteal cysts.

BACKGROUND: The purpose of this study was to introduce the arthroscopic internal drainage with anterior-anteromedial approach for the treatment of popliteal cysts in children. To compare its clinical efficacy with open surgery. METHODS: This was a retrospective case-control study of 102 patients diagnosed with popliteal cysts from January 2018 to February 2020 who received surgery. The study included 27 cases with minimally invasive group (MI group) and 75 cases with open surgery group (OS group). The MI group included 21 males and 6 females, age 6.71 ± 2.16 years who received arthroscopic internal drainage of the cysts to adequately widen the valve opening between the cyst and the articular cavity, excised the fibrous diaphragm without complete excision of the cyst wall. The OS group included 57 males and 18 females, age 6.21 ± 1.67 years who received open excision. The clinical parameters regarding the preoperative characteristics and surgical results were compared. Ultrasound or MRI was used to identify the recurrence of the popliteal cysts. Rauschning-Lindgren grade was recorded to evaluate the clinical outcome. RESULTS: All patients were followed up for at least 24 months. There were no significant differences between the two groups in age, gender, left and right sides, disease time, cyst size, length of hospitalization, preoperative Rauschning-Lindgren grade (p > 0.05). At the last follow-up, the preoperative and postoperative Rauschning-Lindgren grade was improved in both groups. Compared with the OS group, operation time was significantly shortened in the MI group (28.89 ± 4.51 min vs 52.96 ± 29.72 min, p < 0.05). The MI group was superior to the OS group in terms of blood loss and plaster fixation, with statistical significance (p < 0.05). There was obvious difference in recurrence rate between the two groups (0% vs 17.33%, p = 0.018). No postoperative complications occurred during the follow-up period. CONCLUSIONS: Compared with open excision, the treatment of popliteal cyst in children by arthroscopic internal drainage to expand the articular cavity and eliminate the "one-way valve" mechanism between the cyst and the articular cavity exhibits better clinical outcomes and significantly reduces the recurrence rate, which is worthy of further clinical promotion.

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.

[The Baker's cyst - a blunt sword of Damokles in radiosynoviorthesis (RSO)?] / Die Bakerzyste ­ das stumpfe Damoklesschwert bei der Radiosynoviorthese (RSO)?

The existence of a popliteal Baker's cyst was regarded as a contraindication for radiosynoviorthesis of the knee joint since decades. A so-called "ventile mechanism" was discussed leading to a significant concentration of the intraarticularly applied, high energy beta emitting radiopharmaceutical yttrium-90-colloid in the cyst. This cyst arises from a bursa beneath the tendon of the medial head of the gastrocnemius muscle, normally communicating with the knee joint space. Since the cyst wall is much thinner than the knee joint capsule, a radiogenic rupture of the cyst was feared, leading to severe radiogenic necroses of the surrounding soft tissue. Due to this potential hazard, knee joint ultrasound is mandatory prior to radiosynoviorthesis to check for any popliteal cysts. New studies however decline the risk of a radiogenic cyst rupture after an appropriately performed radiosynoviorthesis of the knee joint.In case of a preexistent cyst rupture, the risk of a radiogenic tissue damage remains an issue and magnetic resonance imaging (MRI) is the method of choice to exclude this potential hazard. However, MRI sometimes leads to equivocal results. Scintigraphy of the knee joint after intraarticular application of Tc-99m-nanocolloid offers the possibility to check for the integrity of the Baker's cyst in these patients to be sure that radiosynoviorthesis will not lead to a relevant extraarticular leakage with soft tissue necroses. This study describes the procedure of intracavitary distribution scintigraphy by means of representative case reports.

Factors affecting Baker cyst volume, with emphasis on cartilage lesion degree and effusion in the young and middle-aged population.

BACKGROUND: The principal aim of this study was to investigate the presence of factors affecting Baker's cyst volume in young and middle-aged populations. METHODS: Open cyst excision with valve and capsule repair, as well as knee arthroscopy, were used to treat eighty-five patients. The cases were categorized in terms of age, effusion, chondral lesion degree, meniscal tear degree, and Lindgren scores. An ultrasonography (USG) device was used to calculate the cyst volume. The IBM-SPSS 22 program was used for statistical analysis and to assess the relationships between variables using Spearman's correlation tests. RESULTS: The degree of chondral lesion was moderately and positively correlated with cyst volume in the total population (correlation coefficient: 0.469; p < 0.05). The degree of the chondral lesion was moderately and positively correlated with the degree of effusion (correlation coefficient: 0.492; p < 0.005). The cyst volume was weakly and positively correlated with the degree of effusion (correlation coefficient: 0.20; the correlation was at the limits of statistical significance p = 0.07 < 0.08). CONCLUSIONS: This study revealed that an increase in chondral lesion severity increases the amount of effusion and cyst volume.

When meniscus 'tears' make the Baker's cyst 'cry': a story on knee ultrasound.

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Prevalence and associations of incidental nonvenous duplex findings discovered during lower extremity venous imaging.

OBJECTIVE: Venous duplex imaging defines venous pathology (VP). Unexpected clinically relevant findings are also found but rarely mentioned in the literature. This study aims to define the prevalence of ancillary findings (nonvenous duplex) by study type and venous outcome and subgroup associations with primary study indication and risk factors. METHODS: Our vascular laboratory database was queried for lower extremity venous duplex studies with comments regarding ancillary findings and associated patient demographics, primary study indication, associated conditions, and venous study outcome. RESULTS: There were 52,215 venous studies performed, 48,425 to evaluate for venous occlusion (acute/chronic) and 3790 for venous reflux. Of these studies, 15,810 found VP and 36,405 found no venous disease. There were 875 studies with venous disease that had ancillary duplex findings (5.5%) noted as 559 (3.5%) with prominent lymph node(s) (LN), 179 (1.1%) Baker's cyst (BC), 44 (0.3%) hematoma/mass (HM), 31 (0.2%) arterial aneurysm, and 16 (0.1%) arterial occlusion. There were 3130 studies free of VP with ancillary findings (8.6%) noted as 2258 (6.2%) prominent LN(s), 626 (1.7%) BC, 156 (0.4%) HM, 37 (0.1%) arterial aneurysm, and 22 (0.06%) arterial occlusion. The overall prevalence of ancillary findings was 8.62%. Analysis demonstrated statistically more ancillary findings in venous occlusion (odds ratio [OR], 1.25) studies, which was the largest group at 13 to 1. Studies free of venous disease had more ancillary findings (P < .001) with an OR of 1.88 and similar results were noted for LN(s), BC, and hematoma. Studies with VP favored a finding of aneurysm (OR, 0.52). Subgroup analyses demonstrated that those with prominent LN(s) were statistically older and male and BC statistically older in those with coexistent venous disease. BC subgroup analysis showed that studies free of venous disease were 2.5 times more likely to report pain as the primary study indication (P < .0001). In general, within ancillary subgroups, leg symptoms were statistically more prominent on the side with ancillary pathology and free of venous disease. CONCLUSIONS: Ancillary findings are not uncommon and are more common in studies found free of VP. The most common are LNs, BC and HM and, within subgroups, significant leg symptoms favors the presence of ancillary findings without coexisting venous disease. Ancillary findings should be an integral part of a quality report.

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.