Arthroscopic cystectomy for Baker's cysts with and without one-way valve lesions: incidence of one-way valve lesion, associated pathologies, and clinical outcomes.

INTRODUCTION: A one-way valve lesion plays an important role in the formation of Baker's cysts and serves as an important landmark for accessing these cysts during arthroscopic surgery. This study aimed to investigate the incidence of one-way valve lesions and their effect on clinical outcomes in patients who underwent arthroscopic cystectomy for Baker's cysts. MATERIALS AND METHODS: Patients who underwent arthroscopic cystectomy for Baker's cysts between June 2005 and November 2017 were retrospectively reviewed. Patient demographic characteristics, radiologic/arthroscopic findings (presence of one-way valve lesions, concurrent chondral and meniscal lesions, and cyst wall thickness), and clinical outcomes (clinical recurrence rate, Lysholm score, and complications) at the 2-year follow-up were evaluated. Subgroup analysis was performed to compare clinical outcomes between patients with and without one-way valve lesions. RESULTS: Thirty patients (mean age, 57.4 ± 9.4 years) were included in this study. One-way valve lesions were surgically documented in 11 patients (36.7%). Ten patients (33.3%) had chondral lesions with an International Cartilage Repair Society grade ≥ 3, and 23 patients (76.7%) had concurrent chondral and meniscal lesions. At the 2-year follow-up, none of the patients had experienced clinical recurrence; the mean Lysholm score was 76.3 ± 17.5 (48-100). Three patients reported persistent pain, while two reported numbness or paresthesia. Subgroup analysis showed no significant differences in clinical recurrence rates, Lysholm scores, and complication rates between the groups. CONCLUSIONS: The incidence of one-way valve lesions during arthroscopic cystectomy for Baker's cysts was lower than that previously reported. Arthroscopic cystectomy showed good clinical results in patients with and without these lesions.

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.

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.

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.

The prevalence of periarticular lesions detected on magnetic resonance imaging in middle-aged and elderly persons: a cross-sectional study.

BACKGROUND: Previous studies showed that among persons with radiographic knee OA, periarticular lesions were significantly more common among participants with knee pain than those without. However, data were derived mostly from persons with knee OA, and there were few normal participants without knee OA in the data analyses. The objectives of this study were to investigate the prevalence of periarticular lesions detected by magnetic resonance imaging (MRI), and to examine their prevalence according to the presence of knee pain and radiographic knee osteoarthritis (OA) in community residents in Korea. METHODS: Demographic and knee pain data were obtained by questionnaire from 358 participants of the population-based Hallym Aging Study who were recruited irrespective of the presence of knee OA or pain. Radiographic evaluations consisted of weight-bearing knee anteroposterior radiographs and 1.5-T MRI scans. Periarticular lesions included prepatellar or anserine bursitis, Baker's cyst, and tibiofibular cyst. The prevalence of each lesion in subjects with knee OA or knee pain compared to those without was examined by a chi-square test. RESULTS: The mean age of the subjects was 72 years and 50.6% were female. Radiographic knee OA was present in 34.5%. The most prevalent peri-articular lesion was Baker's cyst (27.9%), followed by tibiofibular cyst (9.5%). Anserine bursitis and tibulofibular cyst were more common in subjects with knee OA (17.5% vs 2.2% for anserine bursitis, 15.8% vs 6.1% for tibiofibular cyst in subjects with and without OA, respectively), while Baker's cyst and anserine bursitis were more common in subjects with knee pain (36.3% vs 21.8% for Baker's cyst, 14.4% vs 2.5% for anserine bursitis in subjects with and without knee pain, respectively). CONCLUSIONS: Periarticular lesions on MRI of the knee are common in middle-aged and elderly persons. Anserine bursitis and Baker's cysts are more common in subjects with knee pain compared to those without.

[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.

Popliteal cysts and subgastrocnemius bursitis are associated with knee symptoms and structural abnormalities in older adults: a cross-sectional study.

INTRODUCTION: The role of popliteal cysts and subgastrocnemius bursitis in knee joint homeostasis is uncertain. The aim of this study is to describe cross-sectional associations between popliteal cysts, subgastrocnemius bursitis, knee symptoms and structural abnormalities in older adults. METHODS: A cross-sectional sample of 900 randomly-selected subjects (mean age 63 years, 48% female) were studied. Knee pain, stiffness and dysfunction were assessed by self-administered Western Ontario McMaster Osteoarthritis Index (WOMAC) questionnaire. Radiographic knee osteophyte and joint space narrowing (JSN) were recorded. Magnetic resonance imaging (MRI) was utilized to assess popliteal cysts, subgastrocnemius bursitis, cartilage defects and bone marrow lesions (BMLs). RESULTS: Popliteal cysts were present in 11.7% and subgastrocnemius bursitis in 12.7% of subjects. Subgastrocnemius bursitis was more common in those with popliteal cyst (36.2% versus 9.7%, P <0.01). In multivariable analyses, popliteal cysts were significantly associated with increased osteophytes in both medial and lateral tibiofemoral compartments while subgastrocnemius bursitis was associated with increased osteophytes and JSN in the medial tibiofemoral compartment. Both were significantly associated with cartilage defects in all compartments, and with BMLs in the medial tibiofemoral compartment. Furthermore, both popliteal cysts and subgastrocnemius bursitis were significantly associated with increased weight-bearing knee pain but these associations became non-significant after adjustment for cartilage defects and BMLs. CONCLUSIONS: Popliteal cysts and subgastrocnemius bursitis are associated with increased symptoms as well as radiographic and MRI-detected joint structural abnormalities. Longitudinal data will help resolve if they are a consequence or a cause of knee joint abnormalities.

Longitudinal assessment of cyst-like lesions of the knee and their relation to radiographic osteoarthritis and MRI-detected effusion and synovitis in patients with knee pain.

INTRODUCTION: The purpose of the present study was to determine the prevalence of cystic lesions and cyst-like bursitides in subjects with frequent knee pain and to assess their relation to radiographic osteoarthritis (OA) severity; to describe bilaterality and size fluctuation of the lesions over 6 months; and to assess relations between the prevalence of synovium-lined lesions communicating with the joint capsule and severity of magnetic resonance imaging (MRI)-detected effusion and synovitis. METHODS: One hundred and sixty-three subjects (total 319 knees) aged 35 to 65 with chronic, frequent knee pain were included. Imaging with 3 Tesla MRI was performed at baseline and 6-month follow-up with the same protocols as those used in the Osteoarthritis Initiative. Severity of radiographic OA was assessed using the Kellgren-Lawrence grade (0 to 4). Severity of effusion and synovitis was graded 0 to 3 based on the Whole Organ Magnetic Resonance Imaging Score system. The associations of cysts and cyst-like bursitides and severity of radiographic OA, MRI-detected effusion and synovitis were analyzed using logistic regression controlling for clustering by person. The Wilcoxon signed-rank test was used to determine whether there was a significant change in the size of lesions between baseline and follow-up. RESULTS: At least one lesion (any type) was present in 222 (70%) knees. The most prevalent lesions were popliteal cysts (40%, 128/319), followed by subgastrocnemius bursitis (15%, 49/319) and proximal tibiofibular joint cysts (8%, 26/319). Bilateral lesions were seen in 49% of the subjects. Only popliteal cysts and subgastrocnemius bursitis showed a significant change in size (P < 0.001). No trend was observed between prevalence of any of the cyst-like lesions analyzed and the increasing radiographic OA severity. Increasing prevalence of subgastrocnemius bursitis was associated with increasing severity of effusion (P = 0.0072) and synovitis (P = 0.0033). CONCLUSIONS: None of the cyst-like lesions analyzed seems to be a marker of radiographic OA severity in knees with chronic frequent pain. Subgastrocnemius bursitis may be used as a marker of effusion/synovitis severity. Bilateral cyst-like lesions are relatively commonly observed in people with chronic knee pain.

Ultrasound Imaging for the rheumatologist XXVII. Sonographic assessment of the knee in patients with rheumatoid arthritis.

The aims of our study were to investigate the prevalence of ultrasound (US) pathologic abnormalities and to compare them with the clinical findings in the knee of rheumatoid arthritis (RA) patients. One hundred RA patients were enrolled in the study. Bilateral US examination of the knee was performed to visualise the presence of effusion, synovial proliferation, bone erosions, femoral cartilage abnormalities, quadricipital and/or patellar enthesopathy. The popliteal fossa and the calf region were also evacuate to detect popliteal cyst. We observed joint effusion in 140 out of 200 (70%) knees. Synovial hypertrophy was present in 115 out of 140 (82%) knees associated with effusion and in 22 out of 115 (19%) knees intra-articular power Doppler (PD) signal was found. Hyperechoic spots within the cartilage layer, suggestive of pyrophosphate crystals deposit, were detected in the knees of 3 patients. US signs of quadricipital and/or patellar enthesopathy were detected in 53 out 200 (26%) knees. Bone erosions were visualised in 16 out 200 (8%) knees. Popliteal cyst was found in 66 out of 200 (33%) joints. US examination of the knee is more sensitive than clinical examination in the detection of joint inflammation and allows for the identification of different patterns of pathologic changes at knee level, including morphostructural changes at both cartilage and tendon level.

Baker's cysts in knees with chronic osteoarthritic pain: a clinical, ultrasonographic, radiographic and scintigraphic evaluation.

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.

Periarticular lesions detected on magnetic resonance imaging: prevalence in knees with and without symptoms.

OBJECTIVE: To evaluate, using magnetic resonance imaging (MRI), the prevalence of periarticular lesions in older persons with or without knee pain, and to assess the association of these lesions with knee pain. METHODS: Subjects ages 45 years and older, with or without knee pain, were recruited from Veterans Affairs medical centers and from the community. Weight-bearing posteroanterior, skyline, and lateral radiographs were obtained in all subjects. Subjects were divided into 3 groups: those with radiographic OA (ROA) and knee pain (n = 376), those with ROA and no knee pain (n = 51), and those with neither ROA nor knee pain (n = 24). A single knee (the more symptomatic one in subjects with knee pain) was imaged with a 1.5T scanner using T1- and T2-weighted and proton-density spin-echo imaging sequences. MRIs were read for the presence of periarticular lesions, which were categorized (according to their general location) as being either peripatellar (prepatellar, superficial infrapatellar, deep infrapatellar) or "other periarticular lesions" (semimembranosus-tibial collateral ligament bursitis, anserine bursitis, iliotibial band syndrome, tibiofibular cyst). RESULTS: Patients with knee pain had more severe radiographic disease than did subjects who were asymptomatic. Peripatellar lesions (prepatellar or superficial infrapatellar) were present in 12.1% of the patients with knee pain and ROA, in 20.5% of the patients with ROA and no knee pain, and in 0% of subjects with neither ROA nor knee pain (P = 0.116). However, other periarticular lesions were present in 14.9% of patients with both ROA and knee pain, in only 3.9% of patients with ROA but no knee pain, and in 0% of the group with no knee pain and no ROA (P = 0.004). CONCLUSION: Although peripatellar lesions are equally common among subjects with knee pain and those without knee pain, other periarticular lesions (including bursitis and iliotibial band syndrome) are significantly more common among subjects with knee pain and may contribute to pain in these individuals.

Prevalence and size of meniscal cysts, ganglionic cysts, synovial cysts of the popliteal space, fluid-filled bursae, and other fluid collections in asymptomatic knees on MR imaging.

OBJECTIVE: The purposes of this study were to evaluate the prevalence and determine the size of meniscal cysts, ganglionic cysts, synovial cysts of the popliteal space, fluid-filled bursae, and other fluid collections on MR images of asymptomatic knees. MATERIALS AND METHODS: MR images of 102 asymptomatic knees were evaluated with regard to the prevalence of meniscal cysts, ganglionic cysts, synovial cysts of the popliteal space, fluid-filled bursae, and other fluid collections. The MR examinations were performed in patients (mean age, 42.8 years; age range, 18-73 years) with clinically suspected meniscal lesions in the contralateral knee. The craniocaudal, anteroposterior, and mediolateral diameters of detectable abnormal fluid collections were measured. RESULTS: Medial meniscal cysts (mean size [craniocaudal x anteroposterior x mediolateral], 9 x 6 x 13 mm) were found in four asymptomatic knees. Neither lateral meniscal cysts nor ganglionic cysts of the cruciate ligaments were identified. Twenty-six synovial cysts of the popliteal space (Baker's cyst)-consisting of 11 gastrocnemius portions (mean size, 19 x 8 x 10 mm) and 15 semimembranosus portions (mean size, 20 x 7 x 9 mm)-were found in 19 knees. Twenty-four (92%) of these cysts had a maximal diameter of 30 mm or less. Fluid-filled bursae were found in 49 knees. The deep infrapatellar bursa was most commonly involved (42 knees; mean size, 6 x 3 x 5 mm). Fluid-filled anserine bursae (mean size, 27 x 12 x 10 mm) were detected in five knees. CONCLUSION: Meniscal cysts may be present in asymptomatic knees, at least on the medial side. Synovial cysts of the popliteal space can be found in approximately one fifth of asymptomatic knees. Their maximal diameter is usually smaller than 30 mm.

Popliteal cysts in adults. Prevalence, associated intraarticular lesions, and results after arthroscopic treatment.

The objective of this prospective study was to determine the prevalence of popliteal cysts and the associated intraarticular lesions in a group of 100 patients scheduled for arthroscopic surgery of the knee and to evaluate the results of arthroscopic treatment for these intraarticular lesions without removal of the cyst. One hundred patients without any knee complaints served as a control group. The diagnosis of a popliteal cyst was made on the basis of ultrasonography. The prevalence of popliteal cysts was 20% in the study group and 0% in the control group. Patients with a popliteal cyst had a significantly higher prevalence of medial meniscal tears (70% versus 19%) and of chondral lesions (85% versus 28%). Tears of the lateral meniscus, however, were more evenly distributed (20% versus 36%). Sixteen of 20 patients with a popliteal cyst were available for a follow-up examination 1 to 3 years after the arthroscopic procedure. Eleven popliteal cysts had persisted. Chondral lesions were the most relevant prognostic factor; all patients with persisting cysts had grade III or grade IV lesions. We conclude that the popliteal cyst is a secondary phenomenon and that treatment should address the underlying intraarticular lesions. In cases of osteoarthritis it may be impossible to treat the chondral lesion successfully in terms of eliminating the effusion.

Popliteal cysts in adults: a review.

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.

Knee effusions, popliteal cysts, and synovial thickening: association with knee pain in osteoarthritis.

OBJECTIVE: To evaluate the association of effusions, popliteal cysts, and synovial thickening with knee symptoms in older persons with and without radiographic (XR) osteoarthritis (OA), using magnetic resonance imaging (MRI). METHODS: Subjects with and without knee symptoms were recruited from Veterans Affairs and community sources. All had weight-bearing knee radiographs. Subjects were divided into 3 groups: Knee pain/XROA group had knee symptoms and radiographic OA; No knee pain/XROA group had no knee symptoms and radiographic OA; and No knee pain/no XROA group had no knee symptoms and a normal radiograph. A single knee was imaged using a 1.5 T MR scanner using T1 and T2 weighted and proton density SE imaging sequences. MRI were read for effusion, popliteal cysts, and synovial thickening. RESULTS: The mean age of subjects was 67.0 years (66.6% male). We studied 381 subjects with Knee pain/XROA, 52 with No knee pain/XROA, and 25 with No knee pain/no XROA. The prevalence of moderate or larger effusions was: Knee pain/XROA 54.6%, No knee pain/XROA 15.6%, and No knee pain/no XROA 11.1%. Popliteal cysts were present in 33.0% of Knee pain/XROA subjects, 28.0% No knee pain/XROA, and 9.1% No knee pain/no XROA. After adjusting for the severity of radiographic OA, there was a difference between those with and without knee pain in prevalence of moderate or larger effusions (p < 0.001) and synovial thickening, independent of effusion (p < 0.001), but not in the prevalence of popliteal cysts. Further, among those in Knee pain/OA group, synovial thickening was associated with the severity of knee pain. CONCLUSION: Effusions and popliteal cysts are common in middle aged and elderly people. After adjusting for the degree of radiographic OA, moderate or large effusions and synovial thickening were more frequent among those with knee pain than those without pain, suggesting these features are associated with the pain of knee OA. In those with knee symptoms, synovial thickening is uniquely associated with the severity of knee pain.

MR imaging of Baker cysts --prevalence and relation to internal derangements of the knee.

RATIONALE AND OBJECTIVES: To evaluate the prevalence of popliteal cysts in patients studied with magnetic resonance (MR) imaging. Cyst presence and volume will be related to other internal derangement of the knee. MATERIALS AND METHODS: Three hundred and eighty-two consecutive patients with a MR study of the knee were included. Images were obtained in the three spatial orthogonal planes and evaluated through consensus. Four categories were established for the Baker cyst and synovial fluid (absence, minimum, moderate and massive), and the presence of meniscal, cruciate ligaments and cartilage lesions were recorded. Statistical analysis was carried out with bivariate analysis (chi(2) of Pearson and Gamma tests). RESULTS: From the 382 patients, 145 had Baker cysts (38.0%). Cyst content was minimum in 99, moderate in 34 and massive in 12. Joint effusion was observed in 269 patients (70.4%), being minimal in 140 patients, moderate in 119 and massive in ten. Meniscal lesions were observed in 195 patients (51%), while 58 patients (15%) had a cruciate ligament lesion. Baker cyst had a statistically significant direct relationship with the presence and quantity of synovial fluid (P=0.002) and with the presence and type of meniscal lesion (P=0.01) but not with cruciate ligaments or cartilage lesions. CONCLUSIONS: The prevalence of Baker cysts in MR studies of the knee is high. Its presence and volume are related to the quantity of synovial fluid, and to the presence and severity of meniscal lesions.

Popliteal cysts in children: prevalence, appearance and associated findings at MR imaging.

OBJECTIVE: The purpose of this study was to determine the prevalence of Baker's cysts on MR images in a paediatric orthopaedic population, to investigate the association of Baker's cyst with joint fluid and joint disorders in children, and to compare the MR appearance of Baker's cysts in children with that previously reported in adults. MATERIALS AND METHODS: Reports from 393 MR studies of the knee performed in children aged from 1 to 17 years were retrospectively reviewed for the presence of a Baker's cyst, joint effusion, meniscal tear, anterior cruciate ligament tear, or any other joint disorder. RESULTS: A Baker's cyst was identified in 6.3 % (25/393) of patients. The MR images and clinical charts of patients with a Baker's cyst were reviewed. None of the 25 patients with a Baker's cyst had an associated anterior cruciate ligament tear or meniscal tear. Two patients had osteochondritis dissecans and two others had synovial disease (infection and juvenile rheumatoid arthritis). Joint fluid was demonstrated in 16 % (4/25) of patients with a Baker's cyst. There was no statistically significant association between presence of a Baker's cyst and presence of joint fluid. CONCLUSIONS: Baker's cyst is less prevalent in a paediatric orthopaedic population than in an adult population. In children, it seems that Baker's cyst is seldom associated with joint fluid, meniscal tear, or anterior cruciate ligament tear. On MR images, a communication between the Baker's cyst and the joint was not demonstrated in any of the patients. In addition, the presence of debris and cyst leakage was not observed.