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.

Popliteal (Baker's) Cysts in the Setting of Primary Knee Arthroplasty

BACKGROUND

Popliteal (Baker's) Cysts are rare complications of knee arthroplasty. Enlargement, irritation, or rupture of the cyst can lead to significant pain, tightness, and tenderness. The literature regarding popliteal cysts occurring following knee arthroplasty is limited and does not report prevalence, natural history, and treatment of popliteal cyst in the setting of knee arthroplasty.

METHODS

Following Institutional Review Board approval, 2,025 primary total and partial knee arthroplasties by four surgeons at one institution from 2011-2016 were reviewed for occurrence of popliteal cysts. Twelve cases occurring after arthroplasty were identified, including four unicompartmental knee arthroplasties and eight total knee arthroplasties. Demographic data were evaluated and symptoms, time of onset following arthroplasty, attempted treatment strategies, and success or failure of attempted treatments or interventions were recorded.

RESULTS

The mean age of patients that presented with a popliteal cyst was 63.6 years old (range = 45 - 78 years). There were 5 males and 7 females. The mean BMI was 26.32 (range = 19.0 - 35.0). In 2,205 primary knee arthroplasties performed from 2011-2016 (including 175 partial and 1850 total), the prevalence of popliteal cysts following surgery was 0.6% (n=12). All popliteal cysts were discovered between six weeks and two years following surgery, with the majority occurring during the first year. Twenty-five percent (3/12) of patients presented with minimal symptoms. These were managed expectantly. Seventy-five percent (9/12) were symptomatic. One patient had only a diagnostic ultrasound, two patients underwent ultrasound-guided aspiration and steroid injection, three underwent simple aspiration. Two underwent surgical excision. One cyst ruptured. All cases went on to symptomatic resolution. There was no association with diabetes, smoking, or body mass index. A disproportionately high number (25% or 4/12) occurred in partial knee arthroplasty.

CONCLUSION

While popliteal cysts following primary total knee arthroplasty are rare, they can become a persistent and even disabling problem for arthroplasty patients. Given the lack of formalized recommendations in the existing literature, we propose a treatment algorithm that has been successful in our clinic, including observation initially, ultrasound-guided injection/aspiration if symptomatic, and surgical excision as a last resort.

LEVEL OF EVIDENCE

Level IV.

[Features of pathological changes of fibro-cartilaginous tissue knee in patients with Baker cyst.]

OBJECTIVE

Using magnetic resonance imaging (MRI) to evaluate the characteristics of pathological changes of fibro-cartilage of the knee in patients with Baker cyst, to assess the compliance of degrees of damage stages of osteoarthritis on a scale of Kellgren–Lawrence (K–L), and compare the results with the data of other researchers.

MATERIAL AND METHODS

This study included patients (38–82 years) with a cyst Baker accidentally detected during ultrasound veins of the lower extremities. The subjects underwent a single knee MRI. MRI was made in three dimensions using 3D gradient-echo protocol. Independent radiologist evaluated the presence and severity of chondral defect osteophytosis, damage to the menisci and ligaments, intraosseous edema and subchondral cysts. The osteoarthritis stage of the knee were identified by X-ray performed in a standing position in the standard two projections, with K–L scale.

RESULTS

In this study, the results of a survey of 20 people, whose average age was 57.2 years. According to the radiological scale of K–L two patients were assigned to the stage 0 degree, 5 people to stage 1, 2, 4 each, and 3 – to stage 3. Synovitis of various severity was detected in 85% of the studies. Nineteen visualized the patellar cartilage damage, the condyles of the femur and tibia are most commonly affects the joint area. Among the most commonly injured ligament anterior cruciate ligament was determined – 9 (45%) patients in the same amount of detected intramedullary edema condyles femur and tibia. Eighteen subjects had at least one anomaly meniscus detectable by MRI, while in 11 (55%) persons were deviations, at least two or more regions of the knee examined.

CONCLUSIONS

Our results suggest that not all visualized on MRI degenerative damage to intra fibro-cartilaginous tissue correlate positively with the stages of osteoarthritis of the knee, identified by standard radiographs and may not significantly affect the onset and progression of synovial cyst of the popliteal region.

Massive baker cyst resulting in tibial nerve compression neuropathy secondary to polyethylene wear disease

Symptomatic synovial cyst formation is an infrequent, late complication after total knee arthroplasty. Most often, these cysts are found incidentally. However, rarely they may become larger leading to significant pain and disability. The formation of gigantic cysts necessitating revision knee surgery has been detailed in a few case reports. To the author's knowledge, this is the first report in the medical literature that describes peripheral neuropathy of the tibial nerve secondary to a massive Baker cyst after total knee replacement.

[Popliteal cysts: etiologic and therapeutic approach]

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.

Ultrasound monitoring of the treatment of clinically significant knee osteoarthritis

OBJECTIVES

The study presented an ultrasound (US) monitoring of treatment as a new imaging US method with the results of therapy of clinically significant knee osteoarthritis.

BACKGROUND

X-ray is widely used for knee osteoarthritis classification, which does not involve the evaluation of the soft tissue. High frequency and high resolution US of joints (arthrosonography, echoarthrography) assess not only morphologic but also functional changes in the knee joint.

METHODS

In the prospective study, 110 patients with clinically significant knee osteoarthritis were treated non-operative. US examination and US monitoring of therapy was performed during 24 weeks therapy period. A remission of pathomorphologic (marginal osteofytes) and pathophysiologic (effusion in anterior knee and Baker´s cyst) attributes were evaluated according the US classification.

RESULTS

Pathomorphologic attributes changes showed a static state, without remission or progression. Pathophysiologic attributes changes showed a remission during the study period. The highest remission was in the first three weeks, 60 % anterior knee effusion and 62 % Baker´s cyst. At the end of study, no changes from the initial US grade was observed in 16 % of effusion in anterior knee and 22 % of Baker´s cyst. Therapeutic resistant Baker´s cyst was present at the end of study in 36 %.

CONCLUSION

We demonstrated a new method - US monitoring of therapy, which can objectivize the efficiency of treatment of clinically significant knee osteoarthritis. We would recommend US monitoring of therapy for the routine use in orthopedic clinical praxis (Tab. 6, Graph 3, Fig. 3, Ref. 15).

Ultrasound-guided aspiration and corticosteroid injection compared to horizontal therapy for treatment of knee osteoarthritis complicated with Baker's cyst: a randomized, controlled trial

BACKGROUND

Combining different therapies, physical therapy agents, pharmacological and physical therapies, generally produces better outcomes for symptoms of knee osteoarthritis (OA) than do isolated therapies.

AIM

To demonstrate if horizontal therapy (HT) and aspiration alone and corticosteroid injection alone or in combination determine pain relief and functional improvement in a group of patients with knee OA complicated with Baker's cyst (BC).

DESIGN

We designed a randomized controlled trial (RCT).

SETTING

Outpatients.

POPULATION

Sixty patients with a knee OA and diagnosis of BC confirmed by means of standard ultrasound (US) evaluation.

METHODS

The trial was conducted as a randomized, controlled trial. Patients who satisfied the inclusion criteria were randomized to either the US-guided (Ultrasound Guided BC aspiration and corticosteroid injection group (Group A), the Horizontal Therapy group (Group B) or the US-guided BC aspiration and corticosteroid injection plus Horizontal therapy group (Group C). Outcome measures included: 1) pain reduction as measured by visual analogue scale (VAS); 2) functional improvement, as measured by WOMAC; and 3) US evaluation at baseline (T0), at one (T1) and four (T2) weeks follow-up.

RESULTS

A total of 60 patients were randomized into group A (N.=20), group B (N.=20) or Group C (N.=20). Patients in group A and in group C, but not those in group B maintained lower pain level at T2 than at baseline, with significant lower VAS values in Group C. As regards US measurements, the maximum axial area did not change as a consequence of the treatment in any of the three groups (P=0.259). Contrarily, sagittal area measurements were influenced by time (P<0.01).

CONCLUSION

Our results show that the group with the best performance for pain, functionality and dimension of BC was that in which combined use was made of horizontal and corticosteroid injection therapies.

CLINICAL REHABILITATION IMPACT

In this study we want to demonstrate the effectiveness of Horizontal Therapy in the treatment of knee OA complicated by BC.

Pseudotumor in a well-fixed metal-on-polyethylene uncemented hip arthroplasty

The incidence of pseudotumor formation has been reported to be 1% in patients with metal-on-metal resurfacing arthroplasties. This complication is not exclusive to these patients. We report a case of pseudotumor formation secondary to femoral head-neck corrosion after a metal-on-polyethylene uncemented total hip arthroplasty.

Cystic adventitial disease of the popliteal artery: An argument for the developmental theory

Cystic adventitial disease is a rare non-atheromatous cause of popliteal artery disease. We report a case of a 54-year-old patient with claudication of the right calf caused by cystic adventitial disease. Intra-operatively, a communication between the adventitia and the knee joint was identified. Connections between the adventitial cyst and the nearby joint have been reported in the literature that support the developmental theory. This theory suggests that cystic adventitial disease is a developmental manifestation of mucin-secreting cells derived from the mesenchyme of the adjacent joint. This case is the first, to our knowledge, in which a communication between joint and adventitia has been clearly documented by operative findings.

Multilobulated popliteal cyst after a failed total knee arthroplasty

Popliteal cyst is a rare finding after total knee arthroplasty (TKA), but when present, it might indicate a malfunction of the TKA related to generation of wear-particles, or loosening. We present a case of a multilobulated popliteal cyst developing in a patient 8 years after primary TKA. The cyst was associated with a mechanical prosthetic loosening. The primary complaint of the patient was pain in the posterior region of the knee. A two-stage procedure consisting of cyst excision at first, followed after 5 months by a revision TKA was performed. Intraoperatively, a darkish, multilobulated cyst with a well-defined thick wall filled with fluid containing polyethylene debris, communicating with the knee joint was found. After 3 years of follow-up, the patient was satisfied and walked without the support of a cane. The patient presented a satisfactory knee range of motion. Clinical, radiological and ultrasound investigations ruled out popliteal cyst recurrence. A dissecting popliteal cyst associated with a failed TKA should be excised because it contains polyethylene debris that constitutes an induced factor for prosthetic loosening. A two-stage procedure with quite a long time in-between, as presented in this paper, can be a useful alternative to manage such a problem, in particular in very old patients associated with other medical problems.

Lyme disease presenting as popliteal cyst in children

Lyme disease is the most common tick-borne disease in North America. Our review of the literature found few reports of Lyme disease presented in the orthopaedic literature. However, Lyme disease presenting as a popliteal cyst, with or without rupture, is rarely reported. We present 4 cases of Lyme disease that initially presented to our pediatric orthopaedic clinic for treatment of a popliteal cyst. The early diagnosis and treatment of Lyme disease may help prevent the often-devastating long-term sequelae of Lyme disease. The goal of this article is to increase the awareness of Lyme disease presenting in children as a popliteal cyst.

The popliteal cyst

A popliteal cyst, originally called Baker's cyst, is a synovial fluid-filled mass located in the popliteal fossa. The most common synovial popliteal cyst is considered to be a distension of the bursa located beneath the medial head of the gastrocnemius muscle. Usually, in an adult patient, an underlying intra-articular disorder is present. In children, the cyst can be isolated and the knee joint normal. The anatomy, etiopathogenesis, clinical presentation, differential diagnosis, imaging and treatment modalities of the popliteal cyst are presented. The authors try to answer some questions dealing with this condition. Is the cyst isolated, can it be treated as such, is its origin always well-defined and does surgical excision provide a permanent cure?

New insights into the development of popliteal cysts

Background

This prospective study was designed to investigate the aetiology of popliteal (Baker's) cysts.

Methods

Some 426 legs in 312 individuals were investigated with ultrasonography for the presence of a popliteal cyst. Participants included healthy volunteers, patients with a painful knee, and a group of patients with signs and symptoms of deep vein thrombosis (DVT). The location, thickness and content of all cysts were recorded. In addition, the popliteal fossa was dissected in four cadaver knees.

Results

The prevalence of popliteal cyst increased with age and was significantly higher in those aged over 50 years (P &lt; 0·001). Compared with controls (incidence 3·0 per cent), cysts were more common in patients with DVT symptoms (9·5 per cent; P = 0·141) and those with painful knees (19·8 per cent; P &lt; 0·001). All cysts were located in the posteromedial aspect of the popliteal fossa; the majority extended between the deep fascia and the medial head of the gastrocnemius muscle. At this level an area without external support of the posterior capsule was identified between the two expansions of the semimembranosus muscle from the medial side (the oblique popliteal ligament and the expansion over the popliteus muscle) and the posterior cruciate ligament from the lateral side. This area was also located in the knee dissections. No association was found between popliteal cyst and acute DVT.

Conclusion

Popliteal cysts are relatively common in patients over 50 years old with a painful knee or with signs and symptoms of DVT. They form in the posteromedial popliteal fossa because the synovial capsule does not provide anatomical support in this region.

An unusual cause of popliteal cyst

We describe a surgical treatment for popliteal cyst in a 41-year-old woman affected by diffuse pigmented villonodular synovitis (PVNS) of the knee with extra-articular spreading. The treatment consists of an arthroscopic synoviectomy followed immediately by an open removal of the cyst. At 28-month follow-up, the patient is asymptomatic and no evidence of recurrence of PVNS has been seen. We believe that this double surgical approach may reduce the probability of recurrence of PVNS.

Gigantic popliteal synovial cyst caused by wear particles after total knee arthroplasty

We present a case exhibiting persistent joint effusion and formation of a gigantic popliteal synovial cyst 8 years after total knee joint arthroplasty. Assessment using flow cytometry revealed that both joint and cyst fluid contained abundant macrophage-phagocytosing wear particles. This finding indicates that wear particles participated in formation of the cyst through the communication between the joint cavity and cyst. Intraoperatively, prominent villous synovial proliferation was observed in both the joint and cyst, and delamination failure of the polyethylene insert was identified. Because no evidence of prosthetic loosening was found, only polyethylene insert revision and synovectomy were undertaken, resulting in a successful outcome. This case suggests that synovial cyst formation in popliteal lesions might represent a sign of wear-particle generation after total knee joint arthroplasty.

Dissecting a popliteal cyst after failed unicompartmental knee arthroplasty

This report documents the first case of a popliteal cyst in a knee with failed unicompartmental knee arthroplasty (UKA). The cyst was treated successfully with the creation of a small communication hole between the posteromedial compartment and the popliteal cyst under direct arthroscopic visualization. This was followed by the replacement of a worn polyethylene insert via a small arthrotomy. Three months later, the popliteal mass had disappeared. This case suggests that a dissecting popliteal cyst may occur after UKA as one of the signs of a malfunction. It also suggests that treatment should be directed toward the joint and not the cyst itself.

Dissecting popliteal cyst resulting from a fragmented, dislodged metal part of the patellar component after total knee arthroplasty

Dissecting popliteal cyst is an uncommon complication after total knee arthroplasty, occurring mainly as a result of either rheumatoid arthritis or a malfunctioning knee prosthesis. Its association with a failed metal-backed patellar component has not been reported since the introduction of the resurfacing of the patella with this kind of design in 1980. We present a case of a late fracture-dislocation of the metal part of the patellar component that migrated to the posterior popliteal fossa, resulting in a cystic mass formation caused by a foreign body granuloma. The patient was treated successfully with a 2-stage operation: first, revision of the total knee arthroplasty and, second, excision of the cyst. The patient had a pain-free functional knee 7 years after surgery, with no recurrence of the symptoms or the popliteal cyst.

The imaging spectrum of Baker's (Popliteal) cysts

Baker's (Popliteal) cysts are frequently encountered on cross-sectional imaging of the knee. These consist of enlarged gastrocnemius semimembranosus bursa which typically communicate with the knee. They may be imaged with a variety of techniques including arthopgraphy, CT, ultrasound and MRI, with the latter two being more commonly used. Examples of bursa imaged with all of the above techniques are demonstrated in the essay, as well as variance of normal appearance and pathological entities including ruptured bursa, abnormally positioned bursa, osteochondromatosis, septic complications of the bursa and pigmented villonodular synovitis.

[Popliteal (Baker's) cyst in a patient with tubercular arthritis. Report of a case and review of the literature]

The Baker's cyst is a distension of the bursa subtendinea and is caused by noninfectious knee effusion secondary to arthrosis, meniscal tears, trauma, rheumatoid arthritis, gout, or any other form of sinovitis, like rheumatoid arthritis. An infected popliteal cyst is much less common; tuberculous arthritis is exceptional, in fact only four cases are described in literature. Herein we describe an additional tbc case of a 51 years old men, who has been initially treated with cytostatic and corticosteroid agents, for a suspected rheumatoid arthritis. The review of the literature suggests the importance of a correct approach to the diagnosis, based on the analysis and culture of the synovial fluid, because delays latency of effective antibiotic therapy can result in permanent joint damage that invalidate the patients.

Popliteal cyst in a patient with total knee arthroplasty: a case report and review of the literature

We report a case of total knee arthroplasty (TKA) failure presenting initially as a large popliteal cyst without bony destruction in a 66-year-old woman. A foreign body gigantocellular inflammatory reaction against polyethylene wear particles was found on histology. The size of the cyst and the absence of bony destruction can be due to an exclusive early intramuscular granulomatous reaction. Progressive loosening of the femoral component and narrowing of the joint space heralded the TKA failure.

[Rheumatologic manifestations of Behcet's disease: report of 309 cases]

PURPOSE

To define the epidemiology and clinical features of Behçet's disease, giving special attention to unusual forms.

METHODS

We retrospectively reviewed the medical records of 309 cases with joint manifestations among 450 cases of Behçet's disease seen over a 20-year period who met the International Study Group of Behçet's disease criteria.

RESULTS

Joint manifestations were present in 68.3% and were inaugural in 34.5%. The knee and ankles were the joints most commonly affected. Monoarthritis, oligoarthritis and polyarthritis were seen respectively in 12, 13.5 and 19.8%. Sacroiliitis is observed in 6%. Unusual forms included destructive polyarthritis (two cases), popliteal cyst (two cases), myositis (two cases) and ankylosing spondylitis (two cases).

CONCLUSION

Joint manifestations are common in Behçet's disease. They are frequently associated with erythema nodosum and necrotic pseudofolliculitis. Polyarthritis is not rare. Their unusual forms deserve to be known.

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.

[Arthroscopic therapy of Baker's cyst]

Arthroscopic therapy of Baker's cysts contains repair of all intraarticular lesions and sealing of the junction between Baker's cyst and the dorsal recessus of the knee joint. All therapeutic steps can be sufficiently done throughout the ventral standard approaches. 18 patients have been treated by this technique between 1992 and 1994. 14 of them were examined after an average of 27 months. In all patients one or more lesions were detected arthroscopically. (12 cartilage-damages, 10 synovialities, 9 meniscal tears, 2 ruptures of the a.c.l.). Cyst recurrence was found arthrosonographically in three cases. These results are comparable to that reported after open cyst extirpation. In our patients we did not see any intra- or postoperative complications. Therefore we consider the arthroscopic therapy of Baker's cyst to be a more comfortable alternative to open extirpation.

Two-stage operation for treatment of a large dissecting popliteal cyst after failed total knee arthroplasty

A symptomatic popliteal cyst after total knee arthroplasty (TKA) is rare, occurring most frequently as a result of intra-articular knee pathology. We present a case of a large dissecting popliteal cyst 7 years after TKA with symptoms of severe calf pain and functional disability. The symptomatic cyst was excised completely in a first-stage operation, and the severely worn TKA was corrected by a second-stage surgical procedure. The patient in this report was pain free and had satisfactory range of knee motion 5 years after the index revision TKA, without recurrence of effusion or popliteal cyst formation.

Anterior arthroscopic synovectomy plus capsuloplasty with a pedicle graft for the treatment of rheumatoid popliteal cysts

OBJECTIVE

To assess the value of arthroscopic synovectomy plus capsuloplasty with a pedicle graft in patients with rheumatoid cysts of the knee.

METHODS

We examined 31 rheumatoid knees in 9 men and 22 women with an average age of 52.5 years at time of operation. Postoperative clinical symptoms were investigated in comparison with each factor examined before the operation.

RESULTS

Postoperative results showed that 74% of the patients were grade 0 (no swelling or pain), 23% were grade 1 (swelling and slight discomfort after strenuous work or sports), and 3% were grade 2 (swelling and tenderness after normal activities). The improvement rate of the patients with arthroscopic synovectomy plus pedicle graft capsuloplasty was significantly higher than that of the untreated controls or patients with arthroscopic synovectomy or pedicle graft capsuloplasty. The preoperative degree of joint effusion, acceleration in the erythrocyte sedimentation rate, radiographic grades, and histological activity in the knee joint at the time of operation were correlated with the final clinical symptoms.

CONCLUSION

Our method may be useful for preventing recurrence of rheumatoid popliteal cysts.

Epstein-Barr (EB) monoarthritis leading to ruptured Baker's cyst

We report a case of Epstein-Barr (EB) infection that presented as an acute monoarthritis of the knee. This formed a Baker's cyst which ruptured into the gastrocnemius. The peripheral and synovial white blood counts were dominated by neutrophils. After repeated aspirations, spontaneous resolution occurred.

Coccidiomycosis presenting as a popliteal cyst

Coccidiomycosis is a fungal infection that primarily causes pulmonary disease. Extrapulmonary dissemination can occur to the musculoskeletal system with the knee joint most frequently involved. This case report describes a patient with coccidiomycosis whose initial presentation was of a popliteal cyst. The need for aggressive surgical and antibiotic treatment to eradicate this infection is discussed. Coccidiomycosis should be considered in a differential diagnosis of patients with popliteal cysts without other obvious etiologies.

[A clinical study of arthroscopic cystectomy on popliteal cysts associated with rheumatoid arthritis]

PURPOSE

We performed a prospective study of arthroscopic cystectomy on popliteal cysts associated with rheumatoid arthritis.

MATERIALS

We performed arthroscopic cystectomy on three patients, four knees, and an open excision of a cyst on one patient, one knee, who had pain and swelling in the popliteal region. Of these five rheumatoid knees, three were grade I on the Larsen radiographic scale, one was II, and one was III. OPERATIVE METHOD: First, we performed synovectomy on the posterior compartment using a multi-portal approach. Second, we confirmed a small communication hole between the posterior compartment and the Popliteal cyst after the synovectomy with an angled arthroscope through the anterior compartment. Third, we enlarged the communication hole and performed a cystectomy (the excision of the membranous septum and the contents of the cyst) from the inside by using a motorized shaver. Finally, we performed a synovectomy on the anterior compartment. The follow-up period ranged from 1 year 6 months to 3 years, 4 months (the mean was 2 years, 4 months).

EVALUATION

We assessed the results using objective oriteria based on the evaluation of swelling, pain and subjective criteria based on the evaluation of the range of motion of the knee and confirmation of the disappearance of the cyst using MRI.

RESULT

We had good results in this study. All the four knees on which the arthroscopic cystectomy was performed had a reduction of pain and swelling right after the operation. The absence of the cyst was verified using MRI. We had no patient whose ROM was aggravated. However, synovitis and popliteal cysts reoccurred in one knee after the open excision (this case had the vasculitis, larsen grade III radiographically, and severe rheumatism).

DISCUSSION

The recurrence rate of the popliteal cyst was very high (over 50%) when a cyst was performed open exision using a posterior approach. Open synovectomy of an anterior compartment needed the manipulation in several cases because of limited knee movement. We had a reduction in pain and a disappearance of the cyst right after operation. Further more, there was no restriction in ROM resulting from this operative method.

CONCLUSION

Arthroscopic cystectomy is a superior procedure for treating the popliteal cysts associated with rheumatoid arthritis.

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.

Proximal dissection of a popliteal giant synovial cyst: a case report

Giant synovial cysts in patients with rheumatoid arthritis are well-recognized soft-tissue masses adjacent to the knee. Cases involving the elbow, hip, and other synovial joints have been reported as well. Regardless of location, these expanding, space-occupying lesions usually present with nonspecific symptoms of swelling and pain. Less commonly, the original presentation may be related to the secondary effects of the cyst on nearby anatomic structures. We present a case of a giant synovial cyst originating posteriorly in the knee, which, rather than dissecting distally into the calf, dissected proximally into the posterior soft tissue of the thigh in a patient with long-standing rheumatoid arthritis.

Baker's pseudocyst in the prosthetic knee affected with aggressive granulomatosis caused by polyethylene wear

It is our belief that this is the first histologically documented case of popliteal cyst secondary to early failure of a cementless knee prosthesis, that occurred after 4 years. The walls of the cyst presented with granulomatous reaction to polyethylene particles. In prosthetic reimplantation successive to excision of the cyst we observed a recurrence of cysts and osteointegration of the prosthetic components, that made reimplantation difficult. Histological assessment of the synovial tissue, periprosthetic tissue and underlying bone showed granulomatous reaction to polyethylene debris. A "tumor" in a patient that has a knee prosthesis can be caused by implant failure. In cases of early failure wear forms large particles and their migration at the bone-prosthesis interface may be obstructed and thus cause a different biological response. If reimplantation is necessary osteointegration of the implants may make surgery difficult.

Baker's cyst in rheumatoid arthritis: an ultrasonographic study with a high resolution technique

OBJECTIVE

To determine the prevalence of popliteal cyst (Baker's cyst) in rheumatoid arthritis (RA), through the use of a very sensitive and non-invasive method, high resolution ultrasonography. The present is the first such report in the literature.

METHODS

Ninety-nine unselected consecutive patients with RA, after undergoing routine clinical and laboratory evaluation, had knee radiographs and ultrasound examinations of both knees, the popliteal fossae and calves, using an Ultramark 9ATL apparatus with a 3 MHz curved array and 10 MHz linear array heads and color doppler ability.

RESULTS

A Baker's cyst was detected in 47 patients (47.5%) and in a total of 67 out of the 198 knees (33.8%). Four of the 67 cysts were ruptured. Only 29 of the 67 cysts (43.3%) had been diagnosed clinically. A statistically significant correlation was found between the presence of a Baker's cyst and clinical and radiologic involvement of the knee by rheumatoid arthritis (p < 0.025, and p < 0.05 respectively). There was a highly significant correlation between the presence of a cyst and ultrasonographically demonstrated joint effusion (p < 0.001).

CONCLUSION

Baker's cyst is very common in RA but it may escape clinical detection. High resolution ultrasound scanning of the area is a simple, highly sensitive and non-invasive technique able to overcome this problem. Therefore, it should be more widely employed by clinicians in the diagnosis of popliteal cysts, which may sometimes be accompanied by significant morbidity.

[Pseudothrombophlebitis due to an expansive popliteal cyst associated with Reiter's syndrome]

Popliteal cysts presenting as thrombophlebitis are unusual diseases of the popliteal fossa and are commonly associated with rheumatoid arthritis or meniscal tears. The authors report the case of a 38-year-old man with Reiter's syndrome in which a synovial cyst of the popliteal space, mimicking symptoms suggestive of deep venous thrombosis, complicated the course of the arthritis. Clinical and diagnostic features of this rare popliteal pathology are discussed and the usefulness of noninvasive diagnostic methods for detecting this disease, in particular that of echotomography, is emphasized. The authors stress the importance of a correct diagnosis in order to avoid the risks of an erroneous anticoagulant treatment.

[Pseudothrombophlebitis syndrome in Reiter's syndrome]

Although the pseudothrombophlebitis syndrome has been studied for a long time it still presents some difficulties to be diagnosed and we can not distinguish it from real thrombophlebitis only by clinical methods. The author presents a Reiter's syndrome patient with recurrent Baker's cyst rupture that develops into pseudothrombophlebitis and discusses some aspects related to this diagnosis and treatment. He calls the attention to this diagnosis mainly in those patients presenting clinical signs of thromboplebitis of the inferior member and knee arthropathy.