Ultrasonographic demonstration of popliteal cysts in rheumatoid arthritis. A noninvasive technique

Arthroscopic anatomic study of posteromedial joint capsule in knee joint associated with popliteal cyst

PURPOSE

The purpose of this study was to examine the arthroscopic anatomy of posteromedial capsule and magnetic resonance imaging (MRI) findings in internal derangement of the knee joint and to analyze the relationship between popliteal cysts and the posteromedial capsule.

METHODS

From 2011 to 2012, a prospective study included 194 knees of consecutive arthroscopic surgeries for assorted knee problems. The anatomy of the posteromedial joint capsule was evaluated arthroscopically and divided into three types by the presence of capsular fold and opening: no capsular fold and no opening (type I), capsular fold without opening (type II), capsular fold with opening (type III). The presence and size of popliteal cyst were documented by MRI.

RESULTS

Type I was observed in 160 knees (82.5 %), type II in 10 (5.1 %) and type III in 24 (12.4 %). Popliteal cysts were found in 25 knees (12.9 %) by MRI. Of these cases, symptomatic popliteal cysts were identified in 12 knees (6.9 %). On 160 knees demonstrated to be type I, only 3 knees (1.9 %) had popliteal cysts in MRI, 6 knees (60 %) in 10 knees of type II and 16 knees (66.7 %) in 24 knees of type III. Therefore, there was a statistically significant relationship between the type of anatomy in the posteromedial capsule and the popliteal cyst (p < 0.001).

CONCLUSION

An association between popliteal cyst and arthroscopic anatomy of posteromedial capsule was demonstrated. Comprehensive understanding and knowledge of the arthroscopic anatomy of posteromedial capsule would contribute to the arthroscopic approach in understanding the pathogenesis of popliteal cyst.

STUDY DESIGN

Development of diagnostic criteria on basis of consecutive patients.

LEVEL OF EVIDENCE

2.

Clinical results of direct arthroscopic excision of popliteal cyst using a posteromedial portal

Purpose

To evaluate the efficacy of the direct arthroscopic excision of a popliteal cyst without additional skin incision using a posteromedial portal based on minimum 2 year follow-up clinical results.

Materials and Methods

From January 2003 to January 2010, 105 patients (111 cases) with popliteal cyst have been treated by a direct arthroscopic excision. Direct arthroscopic excision using a 70 degree arthroscopy and posteromedial portal can correct the valvular mechanism of capsular fold and reduce the complications with no additional skin incision at the popliteal area. In all cases, preoperative magnetic resonance imaging (MRI) was performed to detect combined intraarticular pathology. At 2 years postoperatively, a follow-up ultrasonography or MRI was performed to detect the recurrence of cysts. We used Rauschning and Lindgren criteria for clinical evaluation.

Results

All cases had neither recurrence nor complaints of pain, swelling, or functional impairment more than 2 years after the surgery. At ultrasonography or MRI, no recurrence was found, and 5 complications were 1 skin lesion and 4 hematoma. Postoperatively, Rauschning and Lindgren criteria were more than grade 1.

Conclusions

Direct arthroscopic excision using 70 degree arthroscope and posteromedial portal is an effective method for the treatment of popliteal cyst.

Systematic Review of MRI, Ultrasound, and Scintigraphy as Outcome Measures for Structural Pathology in Interventional Therapeutic Studies of Knee Arthritis: Focus on Responsiveness

Objective.

Validated imaging outcome tools to assess response to therapies in a single joint are required. Our aim was to review the published literature to ascertain the responsiveness of novel imaging techniques as outcome measures in interventional therapeutic studies of knee arthritis.

Methods.

An Ovid Medline search was performed for original articles in English that used imaging techniques to assess response at the knee joint to therapy in osteoarthritis, rheumatoid arthritis, and psoriatic arthritis. Changes in response to therapy were assessed with regard to both internal and external responsiveness.

Results.

In the studies that presented appropriate statistical data to allow responsiveness to be assessed, MRI was generally found to be internally responsive to pathologies imaged, and externally responsive, referenced against both other imaging modalities and biochemical biomarkers of arthritis. Ultrasonography was found to demonstrate internal responsiveness with regard to synovial thickness, effusion size, and popliteal cyst size. External responsiveness was demonstrated against several referenced health status measures. Scintigraphy was found to be externally responsive in the majority of studies, with internal responsiveness demonstrated in 1 study.

Conclusion.

While the imaging techniques appear to be responsive from the data we present, further inspection reveals that interpreting the responsiveness of imaging techniques was difficult, largely because of a lack of standardization of image acquisition, definitions of pathology, and scoring systems. Refined pathological definitions and scoring systems are required to enable the development of valid and responsive tools for interventional clinical trials.

The popliteal bursa (Baker's cyst): an arthroscopic perspective and the epidemiology

The purpose of this study was to establish the incidence of the anatomic structure, the popliteal bursa, in patients undergoing arthroscopy and to determine the relationship to associated clinical and pathological factors. Diagnostic arthroscopy was used to identify the presence of the popliteal bursa in 187 consecutive patients (195 knees). Thirty-seven percent of knees had a popliteal bursa identified by the communication with the posterior medial compartment. The cause of the popliteal bursa was not established by this study. This study refuted the causes proposed by others. The existing erroneous conclusions concerning the cause of the popliteal bursa were probably attributable to the failure to recognize the common continuity of the bursa and the knee joint. When the popliteal bursa is present (37%), it becomes symptomatic by responding to the intraarticular disease because of its continuity with the knee joint.

Synovial cysts in cats

The clinical and radiographic appearance and histological findings in three cats with cystic extensions of the elbow joint capsule are described. The condition was only temporarily alleviated by surgical excision or drainage. In all cases the condition was associated with osteoarthritis.

Ultrasonography as a diagnostic aid in temporomandibular joint dysfunction. A preliminary investigation

Twenty-five patients presenting with temporomandibular joint dysfunction were examined by both ultrasonography and arthrotomography. Ultrasonography produced an image of the TMJ which was at right angles to the image produced by arthrotomography, since the ultrasound picture was in the coronal plane; with ultrasonography the meniscus became more visible during mouth opening. Anterior displacement of the meniscus was associated with deeper location of the condylar head within the glenoid fossa whilst a perforated meniscus produced a bilobed image. This study has provided a preliminary look at ultrasonography of the TMJ and has shown promise for further work. The present images are not ideal for clinical use but they show the possible potential for non-invasive diagnosis which might be provided by higher resolution ultrasound equipment than that used in this study.

Measuring disease activity: comparison of joint tenderness, swelling, and ultrasonography in rheumatoid arthritis

In a prospective study of 6 patients with classic rheumatoid arthritis, we evaluated 3 measures of disease activity: comprehensive joint swelling and joint tenderness counts, and ultrasonography of joints. After baseline data were obtained on these 6 patients, therapy with fenbufen, a new nonsteroidal antiinflammatory drug, was begun. Followup examinations were performed at 4 weeks and 24 weeks after baseline. There were statistically significant differences between joint tenderness and joint swelling findings and between joint tenderness and joint ultrasonography findings (P less than 0.05 by kappa test statistic). In comparisons of joint swelling and ultrasonography, no difference was found (P greater than 0.05). When measures of changes over 6 months were compared, there was a high concordance between improvement in joint swelling and improvement in joint ultrasonography (P less than 0.01). Our results demonstrate that clinical assessment of joint swelling provides an accurate measure of synovial effusion, as confirmed by the more objective ultrasound measurements.

Giant synovial cysts

Giant synovial cysts (GSC) are large, well-defined cavities, containing synovial fluid and lined by a synovium-like membrane, which extend for a variable distance outside the joint cavity. We are reporting 15 cases of GSC of various joints. Rheumatoid arthritis is the most common disease process reported in association with GSC. We suggest that trauma may be a more important cause of GSC than has previously been described. Arthrography and ultrasonography are both helpful in diagnosing these large cysts, especially in the knee to aid in differentiating GSC from thrombophlebitis.

Popliteal cysts: variations on a theme of Baker

Adams in 1840 was the first to describe popliteal cysts, "the enlarged bursa is normally situated beneath the inner head of the gastrocnemius and communicates with the joint by a species of valvular opening." Baker whose name has been given to the cysts suggested in 1877 that the cyst may be a distended bursa related to the semimembranosus tendon. He also suggested that the cyst was connected with the knee synovium and pointed out that the fluid could not return to the joint. He considered that rupture could occur with the formation of calf cysts and that the leak could come from the popliteus bursa. He also commented (Case 1) on difficulty in distinguishing this syndrome from venous thrombosis. He quotes Foucher (1856) who described a typical history of a recurrent cyst with rupture. "An officer first noticed a small swelling in the inner side of the popliteal space, three days after a forced march on a rough road. The tumour only very gradually increased. About eighteen months after its first appearance a sudden effort at extending the leg caused a rupture of the wall of the cyst, the tumour disappearing at the same time that the calf of the leg began to swell. A bandage was applied, but the patient was not laid up. Two years afterwards the cyst was larger than ever; and for a short time the patient was obliged to lie up, as part of the fluid contents of the cyst, after a tight bandaging, had extended on both sides of the knee. Ultimately the disease disappeared." Foucher described 6 cases, but did not observe the communication of the cyst with the knee. Thus, though much of what we know today has been known for over a century, medical text books give scant attention to the subject. The varied clinical patterns derived from popliteal cysts still lead to misdiagnosis with undesirable if not disastrous consequences. Current knowledge of this subject is brought together in this review.

Evaluation of popliteal cysts and painful calves with ultrasonography: comparison with arthrography

Grey-scale ultrasonography will detect reliably the presence of clinically significant popliteal cysts, fluid collections which do not fill by arthrography, and will frequently demonstrate ruptured cysts and the soft tissue changes resulting from a recent leak. Forty-eight knees, in 25 patients with popliteal and/or calf pain were examined by ultrasonography followed by arthrography. Popliteal cysts were demonstrated in 40% (19/48) by ultrasound and in 46% (22/48) by arthrogram. For comparison between arthrography and ultrasonography chi2 = 8.58 and contingency coefficient, phi = 0.42 (p less than 0.01). Acute cyst rupture was shown in 2 patients (8%) by both arthrography and ultrasound. In a further study ultrasonography demonstrated popliteal cysts with a prevalence of 31% (22/72) in 36 patients with definite or classical rheumatoid arthritis compared with 4% (3/72) in controls closely matched for age and sex. This difference in prevalence between the rheumatoid patients and controls was highly significant chi2 = 17.48, p less than 0.001. Ultrasonography, therefore, will demonstrate noninvasively the presence of popliteal cysts, may assist in the diagnosis of rupture, and furthermore will assist in quantitative, sequential assessment of patients with painful knees and calves.

Ultrasonographic diagnosis of extremity masses

Radiographic examination of soft tissue extremity masses is frequently inconclusive. In 18 patients with normal or nonspecifically abnormal radiographs, gray scale ultrasonography provided useful additional information. It was possible to distinguish fluid collections from solid masses, and recurrent venous thrombosis from hematoma in anticoagulated patients. Occasionally, specific diagnoses were suggested on the basis of ultrasonic morphologic characteristics. Diagnoses included soft tissue neoplasms, hematomas, aneurysms, synovial cysts, abscesses, and a lymphocele. Ultrasonically guided percutaneous needle aspiration was diagnostic to two cases. Features of differential diagnostic value relative to extremity solid masses and fluid collections are discussed. Ultrasonography is useful in evaluating these soft tissue masses.

Ultrasound in the diagnosis of popliteal cysts

Ultrasound examination of 9 patients with suggested popliteal cyst was performed and the results are described and discussed. Ultrasonography is a diagnostic alternative which may replace arthrography.

Grey scale ultrasonography and arthrography in evaluation of popliteal cysts

Ultrasonography will reliably detect popliteal cysts of clinically significant size and improvements in ultrasound imaging have enhanced the value of ultrasound in relation to arthrography in the assessment of cyst rupture. Forty-eight knees in 25 patients suspected of having a popliteal cyst were examined by ultrasonography followed immediately by arthrography. Popliteal cysts were demonstrated in 40% (19/48) by ultrasound and in 46% (22/48) by arthrogram. Arthrography detected small cysts not seen with ultrasound, but altrasonic scanning showed cysts which did not fill on arthrography. A ruptured cyst or deep venous thrombosis was suspected in 10 patients. Rupture was confirmed in two patients by arthrography, in both of whom soft tissue changes and attenuation of the distal margin of the cysts were shown by ultrasound.