Arthroscopic Treatment of Popliteal Cyst Through the Posterior Portal: A Comprehensive Clinical Study.

BACKGROUND A popliteal cyst, often perceived as benign, poses potential harm and symptoms. This study focused on arthroscopic treatment through the posterior knee portal at our medical center, aiming to assess its efficacy, safety, and long-term outcomes compared to traditional methods. MATERIAL AND METHODS A retrospective analysis of 20 patients (9 males and 11 females) with symptomatic popliteal cysts (January 2020 to December 2022) undergoing arthroscopic treatment via the posterior knee portal was conducted. Data on demographics, clinical presentation, preoperative imaging, surgical techniques, intraoperative findings, and postoperative Rauschning and Lindgren scores were collected and analyzed. RESULTS With a mean follow-up of 13.6 months (range: 12 to 36 months), all patients had associated intra-articular lesions and were treated. Degenerative cartilage damage was most common (65.0% of cases). The Rauschning and Lindgren score significantly improved after surgery (P<0.05), with no recurrence evident on MRI in any patients. CONCLUSIONS Arthroscopic treatment through the posterior knee portal has good potential for popliteal cyst management. This minimally invasive approach offers benefits such as direct visualization, precise cyst excision, and concurrent treatment of intra-articular pathologies.

[The effect of arthroscopic synovectomy on refractory knee arthritis with popliteal cyst in 153 patients].

Objective: To investigate the efficacy of arthroscopic synovectomy on refractory knee arthritis complicated with popliteal cyst. Methods: Patients diagnosed as rheumatoid arthritis (RA) or spondyloarthritis (SpA) with refractory knee arthritis who underwent knee arthroscopic synovectomy in our hospital from 2010 to 2017 were enrolled, including 20 patients (16 RA, 4 SpA) with popliteal cyst. Clinical data, RA disease activity score (DAS28), SpA back pain score, etc, were collected to evaluate the efficacy of knee surgery. Results: Erythrocyte sedimentation rate (ESR) [58(17, 79)mm/1h vs. 19(9, 30)mm/1h, P< 0.001],C reactive protein (CRP) [3.72(0.92,8.14) mg/L vs. 0.85(0.10,3.08) mg/L,P<0.001], rheumatoid factor [64.6(20.2,193.3) vs. 20.5(10.0,58.4),P<0.001], DAS28 score(4.67±1.25 vs. 2.81±1.23,P<0.001), knee joint discomfort score [5(4,6) vs. 2(1,3),P<0.001] and the volume of knee joint effusion by ultrasound (P<0.05) in 95 RA patients were significantly decreased compared to those before operation. ESR [27(12,54)mm/1h vs. 20 (16,28) mm/1 h,P<0.001], CRP [3.27(1.06,6.95) mg/L vs. 1.41(0.34,3.03)mg/L,P<0.001],knee discomfort score [2(0,5) vs. 1(0,3),P<0.05], back pain visual analogue score (VAS) [5(4,5) vs. 2(1,3), P<0.001], and the volume of knee joint effusion by ultrasound (P<0.001) in 58 SpA patients were significantly lower than those before the operation.The rate [16.84%(16/95) vs. 6.32%(6/95),P=0.023] and grading (P=0.007) of popliteal cyst in RA were decreased after the operation. No statistically difference was observed in the rate [6.90% (4/58) vs. 5.17%(3/58), P=0.697] of popliteal cyst in patients with SpA, yet with a trend of decrease in 4 patients. Conclusion: This study provide evidence that knee arthroscopic synovectomy has a good effect for refractory knee arthritis, which can reduce disease activity, improve joint symptoms and decrease the grading of popliteal cyst.

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.

New-Generation 0.55 T MRI of the Knee-Initial Clinical Experience and Comparison With 3 T MRI.

OBJECTIVES: The aim of this study was to compare the detection rate of and reader confidence in 0.55 T knee magnetic resonance imaging (MRI) findings with 3 T knee MRI in patients with acute trauma and knee pain. MATERIALS AND METHODS: In this prospective study, 0.55 T and 3 T knee MRI of 25 symptomatic patients (11 women; median age, 38 years) with suspected internal derangement of the knee was obtained in 1 setting. On the 0.55 T system, a commercially available deep learning image reconstruction algorithm was used (Deep Resolve Gain and Deep Resolve Sharp; Siemens Healthineers), which was not available on the 3 T system. Two board-certified radiologists reviewed all images independently and graded image quality parameters, noted MRI findings and their respective reporting confidence level for the presence or absence, as well as graded the bone, cartilage, meniscus, ligament, and tendon lesions. Image quality and reader confidence levels were compared ( P < 0.05 = significant), and clinical findings were correlated between 0.55 T and 3 T MRI by calculation of the intraclass correlation coefficient (ICC). RESULTS: Image quality was rated higher at 3 T compared with 0.55 T studies (each P ≤ 0.017). Agreement between 0.55 T and 3 T MRI for the detection and grading of bone marrow edema and fractures, ligament and tendon lesions, high-grade meniscus and cartilage lesions, Baker cysts, and joint effusions was perfect for both readers. Overall identification and grading of cartilage and meniscal lesions showed good agreement between high- and low-field MRI (each ICC > 0.76), with lower agreement for low-grade cartilage (ICC = 0.77) and meniscus lesions (ICC = 0.49). There was no difference in readers' confidence levels for reporting lesions of bone, ligaments, tendons, Baker cysts, and joint effusions between 0.55 T and 3 T (each P > 0.157). Reader reporting confidence was higher for cartilage and meniscal lesions at 3 T (each P < 0.041). CONCLUSIONS: New-generation 0.55 T knee MRI, with deep learning-aided image reconstruction, allows for reliable detection and grading of joint lesions in symptomatic patients, but it showed limited accuracy and reader confidence for low-grade cartilage and meniscal lesions in comparison with 3 T MRI.

Association of complicated Baker's cysts with knee pathologies as compared to simple Baker's cysts.

Baker's cysts (BCs) are known to be associated with intra-articular pathologies. BCs can be classified into 2 types: simple and complicated. Although some studies have focused on BC using magnetic resonance imaging (MRI), which is the gold standard examination, no study has compared knee MRI features in patients with simple and complicated BCs. To assess the relationship between the type of BC (simple vs complicated) and other knee pathologies using MRI. Seventy patients who underwent knee MRI examination due to symptomatic knee were retrospectively recruited from April 2011 to April 2021 at a single hospital. In the knee MRI images, the following were assessed: type (simple or complicated), morphology, volume of BCs, thickness of the suprapatellar recess, presence of synovial proliferation of the suprapatellar recess, grade of knee joint effusion, presence of meniscal tear, and extent of meniscal extrusion. The patients were classified into 2 groups according to the type of BC: simple BC and complicated BC. The differences between the 2 groups were evaluated for all variables. Finally, 52 patients were included in this study, 15 were classified as "simple BC" group and 37 as "complicated BC" group. The volume of complicated BC (median: 4.6, interquartile range - IQR: 1.6-12.4) was significantly greater than that of simple BC (median: 0.7, IQR: 0.3-3.7; P = .007). The presence of synovial proliferation in the suprapatellar recess was significantly higher in complicated BC (91.9%) than that in simple BC (46.7%; P = .001). The thickness of the suprapatellar recess was significantly greater in complicated BC (median: 7.5, IQR: 5.8-10.7) than that in simple BC (median: 4.3, IQR: 2.3-7.6; P = .020). The medial meniscus extrusion was greater in complicated BC (median: 4.1, IQR: 2.8-5.1) than that in simple BC (median: 2.5, IQR: 1.8-4.4; P = .037). After adjusting these P-values using the Holm method, only the presence of synovial proliferation in the suprapatellar recess remained significant (P = .010). Using knee MRI images, we demonstrated that complicated BCs are more associated with intra-articular pathologies than simple BCs; such as cyst volume, amount of the knee joint effusion, synovial proliferation and medial meniscal extrusion. Among them, the presence of synovial proliferation was the most significant factor associated with complicated BCs.

A popliteal giant synovial osteochondroma mimicking a parosteal osteosarcoma.

Both giant synovial osteochondroma and parosteal osteosarcoma are rare musculo-skeletal tumors, often localized in the vicinity of the knee. Misdiagnosis of a malignant bone tumor can entail fatal consequences. Etiology of giant synovial osteochondroma is widely unsolved but is believed to originate from synovial chondromatosis, a mostly benign metaplasia of the synovial membrane. Parosteal osteosarcoma is a low-grade surface osteosarcoma with a propensity of local recurrence and the potential of distant metastasis and therefore requiring a different therapeutical approach. We report the case of a popliteal giant osteochondroma mimicking a parosteal osteosarcoma. Relevant facts of this rare entity regarding pathogenesis, treatment, and differential diagnoses will be discussed.

Arthroscopic treatment of popliteal cyst.

OBJECTIVE: To review the results of arthroscopic treatment of popliteal cysts in our centre and analyse outcomes including complications. DESIGN: Retrospective study. SETTING: University teaching hospital, Hong Kong. PATIENTS: From July 2007 to July 2009, 11 patients with symptomatic popliteal cysts were treated arthroscopically. All of them had preoperative magnetic resonance imaging to confirm the diagnosis, identify the valvular opening, and the associated intra-articular pathology. We used the Rauschning and Lindgren criteria for evaluation. RESULTS: Intra-articular pathology like cartilage degeneration and meniscus tear were commonly associated with popliteal cysts. All patients achieved symptomatic improvement after treatment and the recurrence rate was low. No major complications were encountered. We failed to identify (and correct) any valvular opening in one patient. CONCLUSION: From our experience, we conclude that arthroscopic treatment of popliteal cyst with correction of the valvular opening and treatment of associated intra-articular pathology is effective and safe.

Swelling around a child's knee.

Swellings around the paediatric knee have a large differential diagnosis, although the majority can be diagnosed clinically. Some swellings merit further investigation by Magnetic Resonance Imaging (MRI).

Cyst-like lesions of the knee joint and their relation to incident knee pain and development of radiographic osteoarthritis: the MOST study.

OBJECTIVE: To determine whether intra- and periarticular cyst-like lesions of the knee are associated with incident knee pain and incident radiographic knee osteoarthritis (OA). DESIGN: The Multicenter Osteoarthritis (MOST) Study is a cohort of individuals who have or are at high risk for knee OA. Using a nested case-control study design, we investigated the associations of cyst-like lesions (Baker's, meniscal and proximal tibiofibular joint (PTFJ) cysts, and prepatellar and anserine bursitides) with (1) incident pain at 15- or 30-month follow-up and (2) incident radiographic OA at 30-month follow-up. Baseline cyst-like lesions were scored semiquantitatively using the Whole Organ Magnetic Resonance Imaging Score (WORMS). Conditional logistic regression models were used to assess the relation between these lesions and the outcomes, adjusting for potential confounding factors (i.e., cartilage loss, meniscal damage, bone marrow lesions, synovitis and joint effusion, which were also scored using WORMS). RESULTS: Incident knee pain study included 157 cases and 336 controls. Prevalence of meniscal and PTFJ cysts in the case group was twice that in the control group [9 (6%) vs 9 (3%) and 9 (6%) vs 10 (3%), respectively]. Incident radiographic OA study included 149 cases and 298 controls. Prevalence of grade 2 Baker's cysts and PTFJ cysts in the case group was approximately four times that in the control group [16(11%) vs 9 (3%) and 6 (4%) vs 3 (1%), respectively]. However, none of the cyst-like lesions was associated with incident pain or radiographic OA after fully adjusted logistic regression analyses and correction of P-values for multiple comparisons. CONCLUSION: None of the analyzed lesions was an independent predictor of incident knee pain or radiographic OA. Intra- and periarticular cyst-like lesions are likely to be a secondary phenomenon seen in painful or OA-affected knees, rather than a primary trigger for incident knee pain or radiographic OA.

Ultrasound imaging for the rheumatologist XXVI. Sonographic assessment of the knee in patients with psoriatic arthritis.

Psoriatic arthritis (PsA) is an arthropathy associated to psoriasis, which is part of the spondyloarthropathy family, and which may present with various forms, from mono-oligoarthritis to symmetric polyarthritis mimicking rheumatoid arthritis. In longstanding disease, the symmetric polyarthritis is the most common pattern of PsA, involving small joint of hands, feet, wrists, ankles and, very frequently, knees. Other common features are represented by the inflammation of enthesis and tendons. Ultrasound (US) examinations were performed using a Logiq 9 (General Electric Medical Systems, Milwaukee, WI) equipped with a multifrequency linear probe, working at 10-14 MHz. One-hundred and sixty-six knee joints were investigated in a total of 83 patients. Prior to US assessment, all patients underwent a clinical examination by an expert rheumatologist who recorded the presence/absence of pain, tenderness (detected by palpation and/or active or passive mobilisation of the knee), and knee swelling. Sixty-two (74.7%) knee joints were found clinically involved, while at least one US finding indicative of joint inflammation was obtained in 70 (84.3%) knee joints. In the 59% of the patients we noticed synovial hypertrophy. Enthesitis was present in 39.7% of the subjects studied. This study demonstrated that US detected a higher number of inflamed knee joints and enthesis with respect to clinical assessment in PsA patients.

Arthroscopic treatment of popliteal cysts: clinical and magnetic resonance imaging results.

PURPOSE: This study examined the functional and magnetic resonance imaging (MRI) outcomes of popliteal cysts with combined intra-articular pathologies that were treated arthroscopically by decompression and a cystectomy through an additional posteromedial cystic portal. METHODS: From January 2003 to March 2008, 31 patients were treated with a modified arthroscopic technique to decompress a popliteal cyst. The connecting valvular mechanism was found in all cases at the posteromedial compartment through the anterolateral viewing portal, and it was corrected by resecting the capsular fold through the posteromedial working portal. For cysts with multiple fibrous septa, an additional portal, the so-called posteromedial cystic portal, was used for complete cyst removal. The functional outcome was evaluated by use of the Rauschning and Lindgren knee score. All patients were evaluated by MRI, which documented the popliteal cyst and associated intra-articular lesions preoperatively and at follow-up. RESULTS: All patients could return to their previous daily activities with few or no limitations, and no additional surgery was required after a mean follow-up of 36.1 months (range, 12 to 72 months). The Rauschning and Lindgren knee score showed improved clinical features at the final follow-up in 94% of patients. The follow-up MRI study showed that the cyst had disappeared in 17 knees (55%) and had reduced in size in 14 knees (45%) in the 31 patients. The mean cyst size was reduced significantly from 6.8 to 0.8 cm (P < .0001). CONCLUSIONS: The described arthroscopic technique with or without an additional posteromedial cystic portal is effective for treating popliteal cysts with combined intra-articular lesions. More importantly, follow-up MRI showed that the cyst size was reduced or it had disappeared in all cases, although there was no association between the cyst's disappearance and the follow-up clinical score. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Leukocyte-rich platelet-rich plasma application in post-traumatic osteoarthritis with popliteal cyst: a case report.

Aim: To describe the successful treatment of a Baker's cyst in the setting of post-traumatic osteoarthritis using ultrasound-guided injection of platelet-rich plasma. Setting: Outpatient sports clinic. Patient: 29-year old male basketball player. Case description: The patient presented with 2-months history of right knee pain, 17 months after undergoing right knee anterior cruciate ligament reconstruction surgery. Exam revealed medial joint line and medial collateral ligament tenderness with posterior knee swelling. After aspiration, a corticosteroid injection was administered with temporary symptom relief. Diagnostic ultrasound examination confirmed the Baker's cyst. The patient then underwent two serial leukocyte-rich platelet-rich plasma injections into his right knee. Results: The patient reported complete resolution of pain and cyst size. Conclusion: Leukocyte-rich platelet-rich plasma may be considered as a treatment option for patients with Baker's cysts in the setting of post-traumatic osteoarthritis.

The fate of Baker's cysts at mid-term follow-up after total knee arthroplasty.

AIMS: We report the natural course of Baker's cysts following total knee arthroplasty (TKA) at short- and mid-term follow-up. METHODS: In this prospective case series, 105 TKA patients were included. All patients who received surgery had a diagnosis of primary osteoarthritis and had preoperatively presented with a Baker's cyst. Sonography and MRI were performed to evaluate the existence and the gross size of the cyst before TKA, and sonography was repeated at a mean follow-up time of 1.0 years (0.8 to 1.3; short-term) and 4.9 years (4.0 to 5.6; mid-term) after TKA. Symptoms potentially attributable to the Baker's cyst were recorded at each assessment. RESULTS: At the one-year follow-up analysis, 102 patients were available. Of those, 91 patients were available for the 4.9-year assessment (with an 86.7% follow-up rate (91/105)). At the short- and mid-term follow-up, a Baker's cyst was still present in 87 (85.3%) and 30 (33.0%) patients, respectively. Of those patients who retained a Baker's cyst at the short-term follow-up, 31 patients (35.6%) had popliteal symptoms. Of those patients who continued to have a Baker's cyst at the mid-term follow-up, 17 patients (56.7%) were still symptomatic. The mean preoperative cyst size was 14.5 cm2 (13.1 to 15.8). At the short- and mid-term follow-up, the mean cyst size was 9.7 cm2 (8.3 to 11.0) and 10.4 cm2 (9.8 to 11.4), respectively. A significant association was found between the size of the cyst at peroperatively and the probability of resolution, with lesions smaller than the median having an 83.7% (36/43) probability of resolution, and larger lesions having a 52.1% (25/48) probability of resolution (p < 0.001). At the mid-term follow-up, no association between cyst size and popliteal symptoms was found. CONCLUSION: At a mean follow-up of 4.9 years (4.0 to 5.6) after TKA, the majority (67.0%, 61/91) of the Baker's cysts that were present preoperatively had disappeared. The probability of cyst resolution was dependent on the size of the Baker's cyst at baseline, with an 83.7% (36/43) probability of resolution for smaller cysts and 52.1% (25/48) probability for larger cysts. Cite this article: Bone Joint J. 2020;102-B(1):132-136.

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.

Popliteal artery pseudoaneurysm after arthroscopic cystectomy of a popliteal cyst.

A case of popliteal artery aneurysm after arthroscopic cystectomy of a popliteal cyst is an uncommon complication, and no case has been reported. We present a case of pseudoaneurysm of the popliteal artery after arthroscopic cystectomy of a popliteal cyst 2 months after surgery. Open excision of the pseudoaneurysm and popliteal artery pin-point repair were done. At 30 months' follow-up, both the tibialis posterior and dorsalis pedis pulsations were felt equally on both sides with normal sensations over the limb. Retrospectively reviewing the case, we found that the relation of the popliteal artery and popliteal cyst on preoperative magnetic resonance images can predict the complication of pseudoaneurysm of the popliteal artery. It is better not to shave the lateral aspect of the cyst while performing arthroscopic cystectomy when magnetic resonance images show that the popliteal artery is close to the cyst.

Popliteal Skin Lesion due to Wear Disease in Total Knee Arthroplasty: A Case Report.

CASE: An 87-year-old woman presented with a popliteal skin lesion due to polyethylene wear 13 years following a left total knee arthroplasty. Excisional biopsy through a posterior approach was performed. Histology showed inflammation with granulomas and birefringent foreign body particles in the skin. Cultures remained negative, and revision knee arthroplasty was performed. CONCLUSIONS: A popliteal skin lesion due to polyethylene wear disease in total knee arthroplasty has not previously been described. Patients with an atypical inflammation of the skin with an underlying joint implant should be referred to an orthopaedic surgeon, and dermal biopsies should be checked for birefringent material. LEVEL OF EVIDENCE: Level V.

Sclerotherapy of Baker's cyst with imaging confirmation of resolution.

BACKGROUND: Baker's cysts are commonly encountered in pain management practices. OBJECTIVE: To ascertain if sclerotherapy treatment of a Baker's cyst could produce objectively verifiable MRI imaging changes. DESIGN: Case report. METHODS: A 52-year-old white male with a posterior horn of the medial meniscus tear and a large Baker's cyst who had failed conservative care and drainage was imaged before treatment with sclerosing. Three injections of 12.5% dextrose and anesthetic with sodium morrhuate were injected intraarticular into the right knee after drainage. RESULTS: The Baker's cyst resolved on both postoperative imaging after the completion of care as well as on physical examination. CONCLUSIONS: Prolotherapy in this case study seemed to be an effective treatment for Baker's cyst in this patient.