Clinical and arthrographic studies on the valve mechanism in communicating popliteal cysts

Assessment of Imaging Factors Associated with Baker's Cyst Rupture on Knee MRI

Objectives

To identify the factors associated with Baker's cyst rupture on MRI.

Material and methods

From January 2021 to December 2022, a total of 441 knee MRI examinations in 441 patients (mean age: 47.7 ± 13.8 years) with Baker's cyst were included in this study. Patients were classified into two groups: those with ruptured vs. unruptured Baker's cysts. On knee radiograph, osteoarthritis grade was assessed based on Kellgren-Lawrence grade. On MRI, combined structure injuries, alignment type between semimembranosus tendon and medial head of gastrocnemius tendon, amount of joint effusion, presence of septation, maximal diameters of cyst, and cyst volume were evaluated. Receiver operating characteristic (ROC) analysis was performed to assess the predictive performances of imaging factors for cyst rupture.

Results

There were 146 patients with Baker's cyst rupture and 295 patients without rupture. Patients with cyst rupture showed significantly longer maximal transverse diameter (25.8 ± 6.8 mm vs. 21.6 ± 5.8 mm, p = 0.035) and larger volume (13.3 ± 6.2 cm3 vs. 9.9 ± 5.1 cm3, p = 0.012) than those without rupture. On ROC analysis, maximal transverse diameter of cyst ≥ 22.2 mm (sensitivity = 64.4%, specificity = 54.9%) and cyst volume ≥ 10.9 cm3 (sensitivity = 71.2%, specificity = 58.3%) were the cutoff values for predicting rupture of cyst, respectively. The cyst volume showed significantly higher area under the curve (AUC) than maximal transverse diameter (0.726 vs. 0.642, p = 0.002).

Conclusion

Longer transverse diameter and larger volume of Baker's cyst could be predictive imaging parameters for cyst rupture.

Direct posterior endoscopic excision of atypical popliteal cyst: A case report

Certain types of popliteal cysts do not possess the common pathophysiology of Baker's cysts, such as location or the presence of a one-way valve lesion. The traditional arthroscopic approach and excision of such atypical popliteal cysts are difficult because they do not communicate with the knee joint, especially when located behind the popliteal neurovascular structure. In this case report, we introduce a direct posterior endoscopic technique for the excision of atypical popliteal cysts when accessing them through the traditional arthroscopic approach is unfeasible. In this case, the popliteal cyst was not located between the gastrocnemius medial head and the semimembranosus muscle and did not communicate with the knee joint. Passage of the popliteal artery was observed running on the anteromedial side of the popliteal cyst. Therefore, a direct posterior endoscopic approach was decided for the surgical treatment of the popliteal cyst, and the atypical popliteal cyst was successfully excised without any complications. We also describe the possible advantages and pitfalls of the direct posterior endoscopic approach.

Clinical relevance

Direct posterior endoscopic excision using an intra-cystic portal in the prone position is considered a safe and effective treatment method for atypical popliteal cysts.

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.

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.

Baker's Cyst with Knee Osteoarthritis: Clinical and Therapeutic Implications

OBJECTIVE

Several symptoms are common to knee osteoarthritis and Baker's cyst. To what extent each condition contributes to the patient's discomfort is still a matter of debate. The aim of the present study was twofold: first, to compare the burden of symptoms in patients with isolated knee osteoarthritis and patients with knee osteoarthritis associated with Baker's cyst; second, to assess the outcomes after conservative treatments.

SUBJECT AND METHODS

Patients suffering from monolateral idiopathic knee osteoarthritis were enrolled. Demographic, anthropometric and clinical data (KOOS scale) were collected. Ultrasound evaluation was performed according to standard protocols. On the basis of the clinical presentation different therapeutic options were used (fluid withdrawal, hyaluronic acid and/or steroids injections).

RESULTS

One-hundred and thirty patients were included in the study (97 with isolated knee osteoarthritis, 33 with knee osteoarthritis and Baker's cyst). In basal conditions, lower scores in KOOS sub-scales were observed in patients with knee osteoarthritis associated with Baker's cyst and in patients with effusion compared with patients without effusion. At 3 months after therapy significant higher scores were observed in both groups. At 6 months the scores were unchanged in the patients without Baker's cyst, but worsened in those with Baker's cyst.

CONCLUSIONS

The study shows that Baker's cysts associated with knee osteoarthritis contribute to the burden of symptoms. The conservative treatment of both conditions allows significant improvements, but in the medium term (6 months) the efficacy of the therapy declines in patients with knee osteoarthritis associated with Baker's cyst.

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.

Treatment of Popliteal (Baker) Cysts With Ultrasound-Guided Aspiration, Fenestration, and Injection: Long-term Follow-up

Background:

The purpose of this study was to determine the efficacy of ultrasound-guided aspiration, fenestration, and injection as a treatment in patients with symptomatic popliteal cysts.

Hypothesis:

Ultrasound-guided aspiration, fenestration, and injection (UGAFI) is an effective and safe treatment option for symptomatic popliteal cysts.

Study Design:

Retrospective cohort study.

Level of Evidence:

Level 3.

Methods:

Patients who received a UGAFI of popliteal cysts from 2008 to 2011 were identified. Preaspiration (PA) and follow-up Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, cyst recurrence, complications, cyst complexity, and size were obtained and compared for statistical significance. UGAFI involved aspiration of fluid through a spinal needle, fenestration of the cyst walls and septations, and injection of 1 mL (40 mg) triamcinolone (Kenalog) and 2 mL 0.5% bupivacaine (Sensorcaine) into the decompressed remnant.

Results:

The mean PA WOMAC score (48.55) improved significantly at final follow-up (FFU) to 17.15 (P < 0.0001) for 47 patients. Within the WOMAC subcategories, there was also a significant difference in pain (PA, 10.68; FFU, 3.94; P < 0.0001), stiffness (PA, 4.51; FFU, 1.77; P < 0.0001), and physical function (PA, 31.34; FFU, 12.17; P < 0.0001). There were 6 reaspirations for recurrence (12.7%), and 1 patient underwent unicompartmental knee arthroplasty. There were no infections or other complications.

Conclusion:

Significant clinical improvement in patients with symptomatic popliteal cysts can be achieved via UGAFI as the sole treatment.

Clinical Relevance:

UGAFI is a safe and effective option as the sole treatment modality for symptomatic popliteal cysts.

Intramuscular dissection of Baker's cysts: report on three cases

Baker's cysts are fluid distensions of the gastrocnemius-semimembranosus bursa and are the most common cystic lesion around the knee. Typically cysts enlarge along intermuscular planes around the knee. We report three cases in which the expanding cyst did not respect these planes and dissected along an intramuscular route as confirmed by MR imaging. Such behaviour by Baker's cysts is hitherto unreported in the literature. Possible mechanisms to account for this phenomenon are discussed.

Popliteal cystoscopic excisional debridement and removal of capsular fold of valvular mechanism of large recurrent popliteal cyst

PURPOSE

The purpose of this study was to evaluate the effectiveness of cystoscopic excisional debridement and removal of unilateral flow of the capsular fold of valvular mechanism in the posteromedial corner of the recurrent popliteal cyst.

TYPE OF STUDY

Retrospective review.

METHODS

From March 1998 to May 2000, we treated 14 cases of popliteal cyst by cystoscopic excisional debridement. The cysts were relatively large cysts, about 5 cm in diameter on sonography. Conservative treatment for about 1 year, with about 3 aspirations failed. The mean follow-up duration was 29.7 (24 to 36) months. We used Rauschning and Lindgren criteria for evaluations. We estimated surgical time. Patients underwent sonography 6 months and 1 year after surgery. Pain, range of motion, and recurrence were checked 1 year after surgery.

RESULTS

The average surgical time was 45 (31 to 58) minutes. The time to pain elimination and full range of motion was 1 or 2 days after surgery. No recurrence was noted in any patients. At the last follow-up, patients reported no discomfort or pain, and all had free range of motion. Preoperatively, Rauschning and Lindgren criteria were grade 0 in 0 cases; grade 1 in 3 cases; grade 2 in 10 cases; and grade 3 in 1 case. At 2 weeks after surgery, criteria were grade 0 in 13 cases and grade 1 in 1 case; at final follow-up evaluation, all were grade 0. Hematoma occurred in 1 case. However, in cases lost to follow-up and in short-term follow-up cases, technical errors occurred: not entering within the cyst in 2 cases, extravasion in 1 case, and recurrence in 1 case.

CONCLUSIONS

A popliteal cystoscopic excisional debridement by motorized shaver and removal of the capsular fold of the valvular mechanism is an effective alternative to the open technique of treating popliteal cysts.

Haemorrhage into a popliteal cyst: an unusual complication of haemophilia A

A 7(1/2)-year-old boy with severe haemophilia A had increasing discomfort and pain in his left knee after sledding on ice and landing on his knees. Left knee pain persisted for days despite recombinant factor VIII replacement. Imaging studies showed that by day 10 a popliteal cyst had ruptured, with diffusion of blood into the calf muscles. This case illustrates another possible bleeding complication in patients with a bleeding disorder and a popliteal cyst.

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.

Predictors of rheumatoid arthritis in patients who have monoarthritis in a knee joint

Abstract To determine the predictive factors for rheumatoid arthritis (RA), 79 patients (11 men, 68 women; average age at onset of symptoms 37.1 years) with fixed joint effusion of one knee joint, of minimum 6 months' duration, were divided into three groups: group I, 11 patients (14%) who progressed to RA; group II, 8 patients (10%) with the correct diagnosis, except that RA became apparent during the subsequent follow-up; group III, 60 patients (76%) whose joint effusion resolved. In group I, the degree of joint effusion and the serological values of interleukin (IL)-1β, IgG-RF, and rheumatoid factor (RF) tended to be higher than those in the other groups at the time of our initial examination. The synovial fluid concentrations of IL-1β and IgG-RF in group I were significantly higher than those in the other groups. Magnetic resonance imaging (MRI)-determined stage and histological assessment of synovial inflammation also tended to be higher in group I than in the other groups. This study revealed that it might be possible to predict the outcome of cases of monoarthritis by examining IL-1β and IgG-RF levels in the synovial fluid, in addition to various elevated inflammation signs in the knee joint.

Sonographic detection of Baker's cysts: comparison with MR imaging

OBJECTIVE

The objective of this study was to assess the ability of sonography to reveal Baker's cysts using MR imaging as a gold standard.

MATERIALS AND METHODS

The study group consisted of 36 consecutive knees in 36 patients evaluated with both MR imaging and sonography. Inclusion criteria included axial proton density-weighted or T2-weighted MR images, a sonography report that documented the evaluation of the popliteal region of the knee, and sonographic and MR images that were available for review. The MR images were retrospectively reviewed for the presence of Baker's cyst (fluid signal between the semimembranosus and medial gastrocnemius tendons). Sonography reports were compared with the MR imaging results. The sonographic images were also retrospectively reviewed to determine whether any characteristic findings on sonography were significantly associated with the presence of Baker's cyst on MR imaging.

RESULTS

Retrospective review of MR images revealed 21 Baker's cysts, one myxoid liposarcoma, one meniscal cyst, and 13 examinations with normal findings. The sonography reports revealed that the 21 Baker's cysts were correctly diagnosed, whereas the meniscal cyst and myxoid liposarcoma were misdiagnosed as Baker's cysts. Retrospective review of sonographic images showed a 100% sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in the diagnosis of Baker's cyst when hypoechoic or anechoic fluid was present between the semimembranosus and medial gastrocnemius tendons. No other sonographic characteristics were significant.

CONCLUSION

Identification of fluid between the semimembranosus and medial gastrocnemius tendons in communication with a posterior knee cyst indicates Baker's cyst with 100% accuracy.

Arthrography

A review of knee arthrography is presented. Purpose and technique are discussed and examples of meniscal and extrameniscal lesions are illustrated. Thirty-seven figures and an extensive bibliography are included.

The clinical significance of the valve mechanism in communicating popliteal cysts

In a previous investigation of 41 patients presenting with distended popliteal cysts, a valvular mechanism was demonstrated in 25 cases by means of a specific arthrographic procedure. In the present study the clinical symptoms and signs from the popliteal space and from the joint were assessed and related to the presence or absence of a valvular mechanism. By arthroscopy or arthrotomy seventeen associated knee disorders were diagnosed, e.g., synovitis, osteoarthritis, and tears of a semilunar cartilage. Intraarticular symptoms and intrinsic joint diseases were significantly correlated to the absence of a valve mechanism. The presence of a valve mechanism was indicative of the absence of pathological findings in the joint.