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

Ultrasound for suspected Baker's cyst: A test of limited clinical value?

Introduction

Patients with posterior knee swellings are commonly encountered in clinical practice with the vast majority referred for an ultrasound scan to assess for a clinically suspected Baker's cyst.

Aims

Our aim was to determine the incidence of different pathologies in patients investigated for a posterior knee swelling of a clinically suspected Baker's cyst using ultrasound. We also wanted to investigate the incidence of significant pathologies in the popliteal fossa to assess whether the ultrasound scan findings influenced patient management.

Methodology

Retrospective analysis was performed on all patients who underwent an ultrasound scan for a suspected Baker's cyst or posterior knee swelling at our institution, between January 2017 and December 2018. Patient demographics, ultrasound findings, further imaging investigations and histopathology were recorded. Patient records were followed up for a minimum period of 3 years after ultrasound.

Results

A total of 680 patients had a posterior knee ultrasound scan. Of that, 51% (347/680) had a Baker's cyst and 40% (273/680) had a normal ultrasound scan. Sixty (9%) patients had other abnormalities identified within the popliteal fossa. Four patients had significant findings on ultrasound that required a change of management. No malignancies identified.

Conclusion

This study confirms the high incidence of Baker's cysts in patients presenting with a posterior knee swelling. In the absence of red flag symptoms, ultrasound of the posterior knee for a clinically suspected Baker's cyst is of limited clinical value.

Association between knee inflammation and knee pain in patients with knee osteoarthritis: a systematic review

OBJECTIVE

To systematically review the literature on the relationship between markers of inflammation and pain in patients with knee osteoarthritis (OA).

METHODS

We searched MEDLINE, Web of Science and EMBASE databases from inception until June 2021. Eligible articles had to report on the association between inflammation (as measured by effusion, synovitis, baker's cysts, cytokines and C-reactive protein) and pain in patients with radiographic knee OA. Two reviewers independently performed a screening on title and abstracts, data extraction and risk of bias assessment using the Newcastle-Ottawa Scale (NOS). A best evidence synthesis was conducted for each inflammatory sign included in this review.

RESULTS

37 studies were included. Articles reported on the following measures: effusion or synovitis assessed via ultrasound (n = 9) or magnetic resonance imaging (MRI) (n = 17); baker's cyst (n = 3); cytokine concentrations (n = 11); and C-reactive protein levels (n = 4). The strength of the association between inflammation and pain does not exceed the moderate level (i.e., correlation coefficient values ranging from 0.19 to 0.61). Moderate levels of evidence were found for the association between synovitis (measured with ultrasound or contrast enhanced MRI) and pain. The levels of evidence between effusion (assessed via ultrasound), effusion/synovitis (assessed via non-contrast enhanced MRI), Baker's cyst, cytokines, C-reactive protein and pain were conflicting.

CONCLUSIONS

Different inflammatory markers are associated with pain but the correlation ranges from weak to moderate, and the quality of evidence from conflicting to moderate. Further research is needed to strengthen the level of evidence and to establish mechanisms.

Baker's Cyst

The authors present a case of a Baker's cyst in the right leg of an 86-year-old woman, whose presentation was more typical for a deep venous thrombosis. Both conditions have inflammation and acute calf pain. The clinical manifestations, imaging findings, and treatment of this common emergency department presentation are discussed.

Assessment of knee osteoarthritis by ultrasonography and its association with knee pain

BACKGROUND

Pain is a significant cause of disability in knee osteoarthritis. Conventional radiography is widely used in the assessment of knee osteoarthritis, however radiographic findings do not correlate well with pain. Ultrasonography can be used to evaluate the soft tissue structures of the knee that can be related to pain.

OBJECTIVE

To evaluate pain-related soft tissue structures of the knee with ultrasonography.

METHODS

This cross-sectional study included a total of 198 knees from 99 patients with knee osteoarthritis. Knee pain and functional status were evaluated by performing visual analogue scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). On the ultrasound, cartilaginous thickness, knee effusion and presence of Baker's cyst were assessed and the correlation to pain was investigated.

RESULTS

Baker's cyst was significantly more frequent in symptomatic knees (13.9%) compared to asymptomatic knees (2.5%). Patients with Baker's cyst had a significantly more limited degree of knee flexion, significantly higher resting VAS pain scores and worse WOMAC scores compared to patients without Baker's cyst. In log-linear analysis, presence of Baker's cyst increased the risk of pain by 2.94 times.

CONCLUSION

Ultrasound as a modality that is easily accessible, inexpensive and without radiation exposure is helpful to demonstrate factors related to pain in knee osteoarthritis by allowing assessment of soft tissue structures.

Clinical, Radiographic, and Ultrasound Findings Between Simple and Complicated Baker's Cysts

PURPOSE

The aim of the study was to compare the clinical, radiographic, and ultrasound findings between simple and complicated Baker's cysts.

METHODS

Forty-seven knees with Baker's cysts in 45 patients with knee pain were identified from a chart review. Baker's cysts were classified as simple or complicated according to ultrasound findings. Clinical data, including duration of knee pain, visual analog scale score, Kellgren-Lawrence grade, ultrasound findings, including the size and sonomorphology of the BC, severity of osteophytosis, thickness of joint effusion, meniscal tear, and synovial proliferation of the two types of BC, were compared.

RESULTS

There were 22 knees with a simple cyst and 25 knees with a complicated cyst. The thickness of the suprapatellar effusion in complicated Baker's cysts (5.7 ± 3.0 mm) was significantly greater than that in simple Baker's cysts (3.8 ± 3.2 mm), and the presence of synovial proliferation in the suprapatellar recess was significantly higher in complicated Baker's cysts (22 knees, 88.0%) than in the simple Baker's cysts (12 knees, 54.5%). However, there were no significant differences in demographic, radiographic, and other ultrasound parameters between the two types of BC.

CONCLUSIONS

Synovial proliferation with larger effusion in the suprapatellar recess was more associated with complicated BC than simple BC.

Possible Approaches to Endoscopic Treatment of Popliteal Cysts: From the Basics to Troublesome Cases

Popliteal cysts can be an oppressive symptom in patients with concomitant intra-articular knee pathologies. Because isolated treatment of intra-articular lesions is usually not sufficient to resolve the problems associated with a large symptomatic popliteal cyst, a popliteal cyst should be concurrently addressed with other knee pathologies to maximize patient outcomes. Conservative treatment and open surgical excision are associated with high rates of recurrence, so arthroscopic techniques are the preferred treatment options for recalcitrant cases. Arthroscopic communication-enlargement surgery with cyst wall removal seems to be the most effective. We present a simple and effective basic technique for arthroscopic popliteal cyst treatment and some approaches that allow management of the more demanding cases.

Synovial changes detected by ultrasound in people with knee osteoarthritis - a meta-analysis of observational studies

OBJECTIVES

To examine the prevalence of synovial effusion, synovial hypertrophy and positive Doppler signal (DS) detected by ultrasound (US) in people with knee osteoarthritis (OA) and/or knee pain compared to that in the general population.

METHOD

A systematic literature search was undertaken in Medline, EMBASE, Allied and Complementary Medicine, PubMed Web of Science, and SCOPUS databases in May 2015. Frequencies of US abnormalities in people with knee OA/pain, in the general population or asymptomatic controls were pooled using the random effects model. Publication bias and heterogeneity between studies were examined.

RESULTS

Twenty four studies in people with knee pain/OA and five studies of the general population or asymptomatic controls met the inclusion criteria. The pooled prevalence of US effusion, synovial hypertrophy and positive DS in people with knee OA/pain were 51.5% (95% CI 40.2 to 62.8), 41.5% (26.3-57.5) and 32.7% (8.34-63.24), respectively, which were higher than those in the general population or asymptomatic controls (19.9% (95%CI 7.8-35.3%), 14.5% (0-58.81), and 15.8 (3.08-35.36), respectively). People with knee OA (ACR criteria or radiographic OA) had greater prevalence of US abnormalities than people with knee pain (P = 0.037, P = 0.010 and P = 0.009, respectively).

CONCLUSIONS

US detected effusion, synovial hypertrophy and DS are more common in people with knee OA/pain, compared to the general population. These abnormalities relate more to presence of OA structural changes than to pain.

A qualitative study of the consequences of knee symptoms: 'It's like you're an athlete and you go to a couch potato'

OBJECTIVES

To explore the perceived consequences of knee symptoms on the lives of people aged 35-65 years who had diagnosed osteoarthritis (OA) or OA-like symptoms.

DESIGN

A qualitative study with six focus groups and 10 one-on-one interviews. Constructivist grounded theory guided data collection and analysis. Data were analysed using the constant comparative method.

SETTING

Toronto, Canada.

PARTICIPANTS

51 participants (median age 49; 61% female) who self-reported knee OA or reported knee pain, aching or stiffness on most days of the past month participated in the study.

RESULTS

The core finding, disruption and change, illustrates the range of perceived consequences of knee symptoms in peoples' lives. Participants described the consequences of symptoms on their physical activity (giving up high-level activities or changing how or how much they performed activities), social life (leisure, family and work) and emotional life. Knee symptoms also altered the way participants thought about their bodies and themselves. They reported that they had a new awareness of their knee and that they no longer trusted their knee. They also conveyed that their sense of self was altered.

CONCLUSIONS

This study illuminates the significant and varied consequences that mild to moderate knee symptoms have on the lives of adults age 35-65 years. Findings highlight the need for clinicians to tailor advice and support to the individual's needs considering their symptoms, the consequences of symptoms on their lives and their personal context.

Ultrasonographic findings in a large series of patients with knee pain

Background:

Musculoskeletal ultrasound (MSKUS) is becoming more and more popular in the evaluation of different musculoskeletal abnormalities. The aim of this retrospective study was to document the prevalence and spectrum of MSKUS findings at the painful knee.

Materials and Methods:

All the studies of MSKUS that were performed for the evaluation of knee pain during the previous 2 years at the Department of Radiology in Nazareth hospital were reviewed. Demographic and clinical parameters including age, gender, side, and MSKUS findings were documented.

Results:

Two hundred and seventy-six patients were included in the review. In 21 of them, both knees were evaluated at the same setting (total number of knees evaluated was 297). One hundred and forty-four knees were of the left side. Thirty-three pathologies were identified. 34% of the studies were negative. The most common MSKUS findings were medial meniscal tear (MMT) (20%), Baker's cyst (BC) (16%), and osteoarthritis (OA) (11%). Only one knee of all the knees evaluated in our study showed synovitis. Fifty-three knees (18% of all the knees evaluated) had more than one imaging finding, mosty two and while some had three findings. The most common combination of findings was MMT and BC (8 knees), MMT with OA (8 knees), and MMT with fluid (6 knee). In 67% of the patients who had simultaneous bilateral knee evaluation, at least one knee had no abnormal findings and in 43%, both knees were negative.

Conclusions:

MSKUS has the potential for revealing huge spectrum of abnormalities. In nearly 90% of the positive studies, degenerative/mechanical abnormalities were reported, with MMT, BC, and osteoarthritic changes being the most common.