MRI appearance of meniscal cysts

Comparison of new and old all-inside suture devices in meniscal cyst formation rates after meniscal repair

PURPOSE

We compared the magnetic resonance imaging (MRI)-confirmed cyst formation rate after meniscal tear repair using a new all-inside suture device (N group) versus the older all-inside suture device (O group).

METHODS

Between October 2008 and July 2017, 94 consecutive menisci of 89 patients were diagnosed with meniscal tears and underwent arthroscopic meniscal repair using the all-inside suture device. Five of these patients were lost to follow-up within 12 months and were excluded from the study. The remaining 89 menisci were followed up for at least 12 months and were included in this retrospective cohort study. Older all-inside suture devices (FasT-Fix, Ultra FasT-Fix) were used until December 2012, while the new all-inside suture device (FasT-Fix 360) was used from January 2013 onwards. Meniscal cysts were detected on T2-weighted fat-suppressed MRI at 12 months postoperatively. Multiple logistic regression analysis was used to identify demographic and clinical factors associated with the use of the new all-inside suture device and cyst formation.

RESULTS

In total, 36 and 53 menisci were included in the N and O groups, respectively. The incidence of meniscal cysts was significantly greater in the O group (14 out of 53, 26.4%) than in the N group (two out of 36, 5.56%) (P = 0.012). Two patients in the O group had symptomatic cysts that required removal. Multivariate logistic analyses showed that the cyst formation risk significantly decreased after using the new all-inside suture device than the older all-inside suture devices (odds ratio = 0.139; P = 0.04).

CONCLUSIONS

The MRI-confirmed cyst formation rate after meniscal tear repair was significantly lower using the new than the older all-inside suture devices, indicating that the use of a low-profile device may decrease the cyst formation rate.

The prevalence and characteristics of osseous erosions associated with parameniscal cysts on knee MRI

OBJECTIVES

To determine the prevalence and characteristics of erosions associated with parameniscal cysts (PMCs) and to evaluate the profile of the associated meniscal tears MATERIALS AND METHODS: PACS database was reviewed for knee MRI scans performed over a 5-year period identifying those with PMCs in patients aged 18 years and above. The scans with PMCs were evaluated for the presence of associated osseous erosions. These erosions and PMCs were then analyzed.

RESULTS

The search revealed 6773 knee MRI examinations, of which 555 had confirmed PMCs. There were 7 PMC-associated erosions for a prevalence of 1.3% (95% CI 0.6, 2.6). All erosions involved the proximal tibia. Three of 7 erosions had underlying marrow edema, and 4 out of 7 had an overhanging margin. The mean dimension of all PMCs was 13 mm (SD = 11). The mean dimension of PMCs associated with erosions was 38 mm (SD = 22), while that of PMCs without erosions was 12 mm (SD = 10) (P < 0.001, Wilcoxon rank sum test). Ninety-three percent (95% CI 90.5, 94.8) of PMCs had associated meniscal tears, most commonly of the horizontal type (57%). All PMCs with underlying erosions were associated with meniscal tears, most commonly complex type tears (5/7).

CONCLUSION

Erosions can rarely be associated with contiguous parameniscal cysts (PMCs). These cysts are significantly larger compared with those without underlying erosions.

How to Perform a Giant Parameniscal Cyst Exeresis: Step by Step Technique

Parameniscal cysts are usually small cystic lesions, less than 2 cm in size, found along the meniscal periphery. They are rarely associated with extra-articular palpable mass. Magnetic resonance imaging is the diagnostic method of choice; giant meniscal cysts (>5 cm at its greatest diameter) are very rare, with few cases described in the literature. We describe a step-by-step open exeresis and arthroscopic meniscal suture technique for the treatment of a 9-cm giant parameniscal cyst located on the lateral side of the knee. Treatment of giant meniscal lesions requires caution during dissection and exeresis. Because acute meniscal lesions benefit from meniscal suture rather than meniscectomy, horizontal degenerative lesions may also present excellent results with repair techniques. We conclude that the combination of the open excision of the giant cyst with careful dissection and protection of neurovascular structures, combined with the arthroscopic meniscal suture, is a good strategy to approach such lesions.

Huge intrameniscal cyst successfully treated by open debridement and combined arthroscopic and open repair: a case report

BACKGROUND

Meniscal cysts are not uncommon in clinical practice, with reported incidence rates varying from 1 to 22%. Most meniscal cysts are parameniscal cysts, which are created by extravasation of synovial fluid through the meniscal tear into the adjacent soft tissue. In contrast, intrameniscal cysts in which the fluid collects in the meniscus are very rare. We encountered a teenager with a huge intrameniscal cyst accompanied by a small vertical meniscal tear in the red-white zone of the upper surface of the medial meniscus. A literature search revealed no information regarding the appropriate treatment methods and results for this type of lesion.

CASE PRESENTATION

A 14-year-old boy presented to our outpatient clinic because of right knee pain that had been present for the previous 2 months. The patient participated in Hapkido, but had no specific trauma history. Magnetic resonance imaging revealed a huge intrameniscal cyst located in the central parenchyma of the posteromedial corner of the medial meniscus. In addition, one sagittal slice on MRI revealed a vertical tear in the red-white zone of the upper surface of the medial meniscus. The presence of such a tear accompanied by a huge intrameniscal cyst is very unusual. The patient was treated via arthroscopic inside-out meniscal suture repair and open cystic debridement with additional meniscocapsular suturing. During 4 years of magnetic resonance imaging follow-up, the lesion has completely disappeared and the meniscus has successfully recovered its normal form.

CONCLUSIONS

Our treatment method may be considered as the first choice for young patients who require surgical treatment for large intrameniscal cysts with accompanying small vertical meniscal tears.

Lateral meniscal cysts: long-term clinical and radiological results of a partial meniscectomy and percutaneous decompressive needling

INTRODUCTION

The aim of this study was to describe clinical and radiological long-term results of an arthroscopic partial meniscectomy associated with an outside-in decompressive needling of the cyst for lateral parameniscal cyst.

METHODS

Eighteen patients with symptomatic parameniscal cysts treated between April 2002 and September 2009 were retrospectively included in the study. All patients underwent arthroscopic partial meniscectomy (preserving peripheral rim) and needling of the cyst using a 20-gauge needle. Pre- and post-operative IKDC, Tegner, and Lysholm scores were used to evaluate clinical results. Radiological results were obtained from pre- and post-operative radiographies and post-operative MRI scans. Both supine and weight bearing MRI examinations were performed. Kellgren-Lawrence and WORMS scales were used to evaluate osteoarthritis development of the knee.

RESULTS

The mean follow-up period was 11.6 ± 2.6 years (range 7-15). Horizontal lesions were found in 56% of patients. All patients fully recovered. Mean Lysholm scores passed from mean pre-operative value 52 ± 16.9 to post-operative 85 ± 11.9 (P < 0.01) and mean IKDC scale score changed from 49.5 ± 14.7 to 67 ± 23.5 (P < 0.01). Mean Tegner scores did not change significantly. Post-operative radiographies showed a Kellgren-Lawrence scale grade 0 in six patients (33%), a grade I in eight (44%), a grade II in three (17%), and a grade III in one patient (6%). No patients were found with a Kellgren-Lawrence scale grade IV. No significant differences with pre-operative radiographies were found (chi-square = 1.867; df = 3; P = 0.60) in osteoarthritis development of the knee. Reported WORMS scores had an average of 12.4 ± 5.1. No recurrence of any cysts was observed.

DISCUSSION

Different treatments for lateral meniscal cysts have been proposed, but proper management of the cyst is still controversial. The results of this study suggest that the outside-in needling of the cyst associated with partial meniscectomy is a highly effective, simple, and repeatable technique. Excellent clinical outcomes were reported at a mean follow-up of 11.6 ± 2.6 years (range 7-15). Imaging evaluation showed no significant evolution to osteoarthritis of the knee.

CONCLUSIONS

Partial arthroscopic meniscectomy associated with percutaneous decompressive needling of the cyst wall under arthroscopic visualization showed positive clinical and radiological long-term results. Neither traditional radiographies nor innovative standing MRIs showed findings of osteoarthritis.

Incidence and Risk Factors for Meniscal Cyst After Meniscal Repair

PURPOSE

To investigate the incidence of magnetic resonance imaging-confirmed cyst formation after meniscal repair and to analyze associated risk factors.

METHODS

This retrospective study included cases repaired arthroscopically with the all-inside (AI) technique (using suture anchors) and/or the inside-out (IO) technique between October 2008 and December 2014. A meniscal cyst was detected on T2 fat-suppressed magnetic resonance images. All cases were divided into 3 groups according to the repair method (AI, IO, and combined technique). The incidence of radiographically confirmed meniscal cyst formation in each group and the associated risk factors (age, sex, AI device, medial meniscus, Tegner activity scale preinjury) were analyzed.

RESULTS

A total of 102 menisci in 96 knees were evaluated. The mean follow-up period was 3.8 (range, 2-8) years. The mean patient age was 21.0 (range, 6-53) years. Thirty cases were in the AI group, 60 in the IO group, and 12 in the combined group. Demographically, there were significant differences among groups regarding the number of medial, lateral, and discoid tears; concomitant anterior cruciate ligament tears; Tegner scale; and suture number. Meniscal cysts developed in 14 of 102 cases. Two of the 14 cysts were symptomatic, requiring open cystectomy. The incidence of meniscal cyst was significantly higher in the AI group (12 of 30, 40%) than in the IO group (1 of 60, 1.7%) or the combined-technique group (1 of 12, 8.3%) (P < .001). Both symptomatic cysts were in the AI group and were in continuity with the anchors. Medial meniscus tear (odds ratio = 6.92) and the use of AI suture anchors (odds ratio = 15.03) significantly increased the risk of cyst formation.

CONCLUSIONS

The incidence of meniscal cysts after arthroscopic meniscal repair was 1.7% to 40.0%, depending on the surgical method. Medial meniscus tears and use of an AI device are suggested as risk factors for cyst formation in this retrospective study.

LEVEL OF EVIDENCE

Level Ⅲ, retrospective comparative study.

Post-traumatic Medial Meniscal Cyst in young: A case report

Introduction:

Meniscal cysts are rare, in that cysts of lateral meniscus are 3 times to 10 times more common than those of medial meniscus. Etiology of meniscal cysts includes trauma which results in contusion and haemorrage within the substance of meniscus leading to mucoid degeneration. Degeneration with age results in local necrosis and mucoid degeneration into a cyst, developmental inclusion of synovial cells within the substance of the meniscus and often are a result of extrusion of synovial fluid through a tear of the meniscus, resulting in a one-way valve effect of the tear. Arthroscopic partial menisectomy followed by cyst decompression is currently recommended for treatment of a meniscal cyst.

Case Presentation:

We present a case of 18-year-old female with c/o pain and swelling in right knee had h/o trauma 3 yrs back. On examination, swelling 1x2 cm on medial tibial condyle, firm in consistency fixed to bone. MRI suggests grade 3 horizontal tear in posterior horn of medial meniscus and parameniscal cyst adjacent to medial meniscus. In this report, medial parameniscal cyst was resected using an arthroscopic posterior trans-septal approach. There have been no recurrences to date, and patient returned to her previous level of activity.

Conclusion:

A posterior trans-septal approach is useful for resection of a meniscal cyst arising from the posterior horn of the medial meniscus.

An arthroscopic check valve release improves knee intrameniscal cyst symptoms in adolescent: a case report

Intrameniscal cysts begin with the flow of synovial fluid from a meniscal tear in one direction, enlarging probably as a result of an on-and-off valve mechanism of the tear flap. The current available literature focuses primarily on the necessity for surgery, however a large meniscus resection to remove cysts may place an additional burden on menisci, leading ultimately to knee joint degenerative changes. In this article, we present a rare case of intrameniscal cysts with an isolated horizontal meniscal tear in an adolescent, and describe a new arthroscopic procedure for treating this type of intrameniscal cyst. We performed arthroscopic partial release of the meniscal tear check-valve mechanism, preventing further intrameniscal cyst expansion. The patient's clinical symptoms improved, and this procedure may also be useful in treating intrameniscal cysts with an isolated horizontal meniscal tear and can be considered as an option to preserve meniscal function and minimize degenerative arthritis in young athletes.

'Not Always a Baker's Cyst' - An Unusual Presentation of a Central Voluminous Postero-Medial Meniscal Cyst

Meniscal cysts are rare and often are a result of extrusion of synovial fluid through a tear of the meniscus, resulting in a one-way valve effect of the tear. Arthroscopic partial meniscectomy of the meniscus with intra-articular cyst drainage has become the standard of care. We report a case of an unusually large symptomatic medial meniscal cyst, situated postero-medially and pressing on the posterior cruciate ligament, which was initially clinically misdiagnosed as a Baker’s cyst. The patient had difficulty and pain on squatting. He was successfully treated with arthroscopic debridement and needle decompression; a rarity in literature for such a voluminous perilabral cyst tenting the posterior cruciate ligament. This procedure has the advantage of being able to obtain the cystic fluid for histological and cytological analysis before debridement. This case also highlights the importance of the use of Magnetic Resonance Imaging (MRI) to accurately diagnose a central, posterior knee swelling.

Paralabral cysts in the hip joint: findings at MR arthrography

PURPOSE

The purpose of this research was to retrospectively characterize paralabral cysts of the hip as seen at MR arthrography.

MATERIALS AND METHODS

After Institutional Review Board approval, 704 patients who had MR arthrography were identified over a 3-year period and 40 patients were identified as having a cyst or fluid collection at the hip by MR report. MR images from these 40 patients were retrospectively reviewed by three radiologists where 18 were found to have a paralabral cyst, which were characterized as follows: location, configuration, contrast filling, size of the cyst, extent, direction, and whether associated osseous changes were present. In addition, the acetabular labrum was assessed for tears and, if present, the location and pattern were characterized.

RESULTS

Paralabral cysts were located anterosuperiorly in 56%, anteriorly in 22%, posterosuperiorly in 17%, and anteroinferiorly in 6% of cases. The vast majority (94%) were multilocular and filled with intra-articular contrast medium. The average dimensions were 8 × 7 × 11 mm. The paralabral cyst demonstrated extracapsular extension in 72% of cases, with 39% located between the ilium and gluteus minimus, and 22% between the ilium and iliopsoas. Remodeling of the ilium adjacent to the cyst was observed in 50% of these cases. A labral tear was at the base of the labrum adjacent to the cyst in 78% of cases, while the tear was isolated to the body of the labrum in 22%. Tears were most commonly anterosuperior (55%) or anterior (28%) in location.

CONCLUSION

Our results show that paralabral cysts of the hip are most commonly located anterosuperiorly, are multilocular, fill with intra-articular contrast medium, have average dimensions up to 11 mm, and often extend extracapsularly between muscle and bone where they may remodel the adjacent ilium.

New observations on meniscal cysts

OBJECTIVE

The purpose of this study was to determine the incidence of meniscal cysts, assess the frequency of various magnetic resonance (MR) imaging characteristics, and emphasize radiographic observations not commonly reported.

MATERIALS AND METHODS

A total of 2,095 consecutive knee MR imaging reports from a 22 month period were retrospectively reviewed for the presence of meniscal cysts. Two musculoskeletal radiologists reviewed the cases where cysts were reported. A meniscal cyst was considered present if abnormally increased signal was identified within an enlarged meniscus (i.e., intrameniscal cyst) or if a loculated fluid-intensity lesion with a clear connection to the adjacent meniscus was identified (i.e., parameniscal cyst). Presence or absence of a meniscal tear, intrameniscal and parameniscal signal intensity, patient age, sex, location of meniscal cyst, presence of discoid meniscus, and size of the parameniscal cyst component were recorded. All knee imaging examinations were performed on a 1.5T MR unit. Imaging findings were correlated with arthroscopic reports when available.

RESULTS

A total of 167 cases (8.0%) of meniscal cysts were diagnosed in 161 patients. Of the 167 cysts, 69 (41.3%) were located in the lateral meniscus and 98 (58.7%) in the medial meniscus. In 6 patients (3.7%), meniscal cysts were present in both menisci of the same knee. Twelve (7.2%) meniscal cysts were associated with discoid menisci. Ninety-seven (57.8%) meniscal cysts were associated with meniscal tears. Of the total number of meniscal cysts, 104 (62.3%) had a parameniscal cyst. An isolated intrameniscal cyst was present in 63 (37.7%) cases. One hundred (96%) of the parameniscal cyst components were isointense to fluid on T2-weighted FSE images. All cysts exhibited abnormal intrameniscal signal. Only 14 (8.4%) of the intrameniscal components were isointense to fluid on T2-weighted FSE images. The arthroscopic reports of 88 of the 161 (54.7%) patients were available for review and correlation. A tear extending to the articular surface of the meniscus was reported to be present in 74 of the 88 (84%) arthroscopic examinations.

CONCLUSIONS

Knowledge of the spectrum of findings and the relative frequency of various MR imaging characteristics as well as common potential pitfalls is important to the accurate diagnosis and management of mensical cysts. In particular, controversy exists as to the incidence of articular surface tears in association with meniscal cysts, with some authors reporting greater than 98% correlation with tears. Only 58% of cysts were associated with an articular surface tear. Ninety six percent of the parameniscal signal was isointense to fluid, only 8% of the intramensical signal was isointense to fluid.

MR imaging of intra- and periarticular soft tissues and subchondral bone in knee osteoarthritis

Osteoarthritis of the knee has to be considered a disease of the whole joint. Magnetic resonance imaging allows superior assessment of all joint tissues that may be involved in the disease process, such as the subchondral bone, synovium, ligaments, and periarticular soft tissues. Reliable MR imaging-based scoring systems are available to assess and quantify these structures and associated pathology. Cross-sectional and longitudinal evaluation has enabled us to understand their relevance in explaining pain and structural progression.

Postoperative pain management and acupuncture: a case report of meniscal cyst excision

We report a case of pain management after a meniscal cyst excision, with the use of electroacupuncture (EA). There are a few reports which indicate that postoperative pain management is prerequisite for the patient's optimal recovery, but surveys in the UK and the USA have identified an unacceptable prevalence of poor pain control after surgery, which might increase the risk of a chronic pain state. The conventional treatment of postoperative pain includes systemic medications such as opioids, non-steroidal anti-inflammatory drugs and other non-opioid agents. In our case, the rehabilitation lasted for 6 months without significant benefit. After that period our patient was treated with EA. By the end of the first EA session the relief of pain was notable and after a course of 10 treatments the patient reported complete relief of the symptoms with no recurrence during a 2 year follow up period. In conclusion, this might indicate that EA could be useful for postoperative pain management.

MRI features of cystic lesions around the knee

Cystic lesions around the knee are a diverse group of entities, frequently encountered during routine MRI of the knee. These lesions range from benign cysts to complications of underlying diseases such as infection, arthritis, and malignancy. MRI is the technique of choice in characterizing lesions around the knee: to confirm the cystic nature of the lesion, to evaluate the anatomical relationship to the joint and surrounding tissues, and to identify associated intra-articular disorders. We will discuss the etiology, clinical presentation, MRI findings, and differential diagnosis of various cystic lesions around the knee including meniscal and popliteal (Baker's) cysts, intra-articular and extra-articular ganglia, intra-osseous cysts at the insertion of the cruciate ligaments and meniscotibial attachments, proximal tibiofibular joint cysts, degenerative cystic lesions (subchondral cyst), cystic lesions arising from the bursae (pes anserine, prepatellar, superficial and deep infrapatellar, iliotibial, tibial collateral ligament, and suprapatellar), and lesions that may mimic cysts around the knee including normal anatomical recesses. Clinicians must be aware about the MRI features and the differential diagnosis of cystic lesions around the knee to avoid misdiagnosis.

Tumour and tumour-like lesions of the intercondylar notch of the knee: a pictorial review

A variety of tumours and tumour-like lesions are found in the intercondylar notch of the knee. MR imaging is the technique of choice in evaluating these conditions. Correlation with radiographs is important to identify those lesions containing calcification. This review article discusses the imaging features of tumour and tumour-like lesions involving the intercondylar notch with an emphasis on MR imaging features that suggest a specific diagnosis.

Medial meniscal cyst: a case report

Meniscal cysts are a rare disease constantly combined with a horizontal meniscal lesion. Currently, nuclear magnetic resonance (MRI) is the main diagnostic tool, because of its high sensitivity and specificity, and decompression arthroscopy combined with selective meniscectomy is the treatment of choice. The Authors report a case of a voluminous medial meniscal cyst where instrumental examination, MRI, was fundamental for the preoperative diagnosis of the horizontal meniscal lesion causing the cystic degeneration of the meniscus. The treatment performed was selective meniscectomy of the body and posterior horn of the medial meniscus and decompression of the voluminous cyst by arthroscopy. Physical examination after six months showed the complete resolution of swelling at the medial hemirima, no walking pain and normal range of motion.

High-resolution ultrasonography (HRUS) of the meniscal cyst of the knee: our experience

PURPOSE

This study was undertaken to assess the diagnostic accuracy of high-resolution ultrasonography (HRUS) in the detection of meniscal cysts.

MATERIALS AND METHODS

Over a 2-year period, 1,857 patients underwent magnetic resonance imaging (MRI) of the knee for traumatic or degenerative disorders. All patients with MRI evidence of a meniscal cyst were studied by HRUS. HRUS was also performed on an equal number of patients without MRI evidence of meniscal cyst who were used as a control group. All HRUS examinations were conducted by a radiologist blinded to the MRI findings. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of HRUS were assessed with reference to MRI. All patients underwent surgery, and the resected masses were studied by histological examination.

RESULTS

MRI allowed identification of a meniscal cyst in 52 patients. HRUS enabled correct detection of the meniscal cyst in 49/52 cases. In the control group, HRUS excluded the presence of meniscal cysts in all cases. HRUS had a sensitivity, specificity, PPV and NPV of 94.23%, 100%, 100% and 94.54%, respectively, for the detection of meniscal cysts.

CONCLUSIONS

HRUS is a fairly reliable technique in the detection, characterisation and differentiation of the different forms of meniscal cyst.

MRI for Traumatic Knee Injury: A Review

Magnetic resonance imaging (MRI) is a well-established technique for detecting internal derangements of the knee joint with high diagnostic accuracy. It is an effective tool to select patients for targeted therapeutic arthroscopy. In this article, indications for knee MRI and most commonly used MRI techniques are outlined, followed by an overview of the most frequently encountered traumatic knee derangements in daily practice and their appearance and grading system on MRI. Lesions discussed include fractures, osteochondral lesions, bone bruise, cruciate and collateral ligament lesions, and meniscal tears. Finally, common pitfalls and recent developments in knee MRI are addressed.

Conservative treatment for a symptomatic solitary ganglion cyst of the anterior meniscus invading into the infrapatellar fat pad

Symptomatic meniscal cysts without accompanying meniscal tears are uncommon, especially those which are formed from the anterior meniscus and invading into the infrapatellar fat pad (IPFP). The current recommended treatment for such cysts is excision through open method or arthroscopy. To our knowledge, this is the first case study about a symptomatic solitary meniscal cyst invading the IPFP that was successfully treated with needle aspiration and steroid injection after arthroscopic treatment of the associated disorders. In this paper, similar cases are also reviewed to discuss the treatment and the link between meniscal cyst and meniscal tear.

MR Imaging of Cysts, Ganglia, and Bursae About the Knee

Cystic lesions around the knee comprise a diverse group of entities, ranging from benign cysts to complications of underlying diseases such as infection, arthritis, and malignancy. Their diverse causes result in varied prognoses and therapeutic options. Although the presentation of cystic masses may be similar, their management may differ, thus highlighting the importance of appropriate categorization. MR aids in the characterization of lesions by first localizing them, and then defining their relationship with adjacent structures and identifying any additional abnormalities. For the purpose of this article, the authors limit the scope of their discussion to benign cysts, ganglia, and bursae about the knee.

Arthroscopic meniscal repair and needle aspiration for meniscal tear with meniscal cyst

Treatment of patients with meniscal cysts of the meniscus usually requires surgery. Arthroscopic partial meniscectomy of the involved torn meniscus with intra-articular cyst drainage has become the accepted intervention. However, if the meniscal tear is peripheral, a lot of healthy meniscal tissue is needlessly sacrificed with subtotal meniscectomy. Moreover, the meniscal cyst is not a true cyst, so it may be treated more conservatively after the underlying disease has been corrected. We report a case of a meniscal cyst arising from the anterior segment of the lateral torn meniscus that was arthroscopically repaired with an outside-in technique. With the use of a 19-gauge long needle to penetrate the peripheral rim inframeniscally, a nonabsorbable No. 3-0 nylon suture was passed into the joint and brought out suprameniscally to loop the meniscal fragment. The second suture was passed and was used to secure the meniscal rim and fragment by the same means approximately 8 to 10 mm from the first one. Then the cyst was aspirated. A good result was obtained, and no recurrence of the cyst or mechanical problems occurred after a follow-up of 14 months.

Pericruciate intra-articular lateral meniscal cyst without meniscal tear

A case of intra-articular pericruciate type of meniscal cyst from anterior horn of lateral meniscus without associated meniscal tear is reported with review of literature. To our knowledge such association has not been reported earlier.

When is a meniscal cyst not a meniscal cyst?

Two patients are presented where lesions adjacent to the joint line of the knee were diagnosed clinically and on magnetic resonance imaging (MRI) as meniscal cysts. No concomitant meniscal tears were seen, and the MRI signal was not completely homogenous. The diagnostic imaging influenced the surgical management in a manner inappropriate for the definitive diagnoses of fibromyxoid sarcoma and monophasic synovial sarcoma. Not all cysts produce a purely homogenous signal on MRI due to haemorrhage or high protein content fluid, and not all meniscal cysts are associated with a meniscal tear. In the absence of a meniscal tear and with mixed signal on MRI we advise caution in the diagnosis of a meniscal cyst and advocate shared management with either orthopaedic or radiological colleagues with a special interest in oncology to obtain a tissue diagnosis before definitive treatment.

The MRI appearance of cystic lesions around the knee

This review presents a comprehensive illustrated overview of the wide variety of cystic lesions around the knee. The aetiology, clinical presentation, MRI appearances and differential diagnosis are discussed. Bursae include those related to the patella as well as pes anserine, tibial collateral ligament, semimembranosus-tibial collateral ligament, iliotibial and fibular collateral ligament-biceps femoris. The anatomical extension, imaging features and clinical significance of meniscal cysts are illustrated. Review of ganglia includes intra-articular, extra-articular, intraosseous and periosteal ganglia, highlighting imaging findings and differential diagnoses. The relationship between proximal tibiofibular joint cysts and intraneural peroneal nerve ganglia is discussed. Intraosseous cystic lesions, including insertional and degenerative cysts, as well as lesions mimicking cysts of the knee are described and illustrated. Knowledge of the location, characteristic appearance and distinguishing features of cystic masses around the knee as well as potential imaging pitfalls such as normal anatomical recesses and atypical cyst contents on MR imaging aids in allowing a specific diagnosis to be made. This will prevent unnecessary additional investigations and determine whether intra-articular surgery or conservative management is appropriate.

Comparison of two procedures for meniscal cysts. A report of 35 patients with a mean follow-up of 33 months

BACKGROUND

The cause, pathogenesis, and appropriate treatment of meniscal cysts remain controversial.

PURPOSE

We wanted to evaluate the results of treatment of meniscal cysts with two different operative procedures.

STUDY DESIGN

Prospective cohort study.

METHODS

Two different operative procedures were compared. Sixteen patients (group 1) had an open excision of the cyst performed in addition to arthroscopic examination of the knee. Nineteen patients (group 2) were treated entirely arthroscopically. The postoperative treatment course was the same for both groups. The mean length of follow-up was 33 months.

RESULTS

The results were excellent or good in 86% of the patients (30 of 35) and were equally good for both procedures. Patients with degenerative changes of the knee joint seemed to have a less favorable outcome.

CONCLUSIONS

Good or excellent results can be expected from either open or arthroscopic treatment of meniscal cysts.

A case report of an unusual location of pericruciate meniscal cyst with adjacent bony erosion

Meniscal cysts are uncommon cystic lesions around the knee, and pericruciate meniscal cysts are the most rare types. Here we present an unusual case of a pericruciate meniscal cyst located laterally to the anterior cruciate ligament (ACL), causing erosion of the adjacent tibial plateau.

Ganglion cysts of the cruciate ligaments

PURPOSE

To evaluate the MR findings of ganglion cysts of the cruciate ligaments in correlation with clinical findings.

MATERIAL AND METHODS

We reviewed 12 patients with ganglion cysts of the cruciate ligaments obtained from a medical record of 4153 consecutive patients referred for knee MR examinations. All patients presented with chronic knee pain and 4 had restriction of knee motion. The MR imaging findings of the cysts were evaluated and correlated with clinical manifestations.

RESULTS

Seven ganglion cysts were found in the posterior cruciate ligaments and 5 in the anterior cruciate ligaments. All cysts were lobulated (n=7) or fusiform (n=5) in shape, 1.8-4.5 cm in size, along the posterior surface in the proximal or distal end of the ligaments. Ten patients had arthroscopic resection or aspiration of their cysts, became symptom free and had no recurrence on follow-up MR examinations. Two cysts reduced in size spontaneously by conservative treatment.

CONCLUSION

MR imaging can offer useful information in detection and diagnosis of patients with chronic knee pain due to ganglion cysts of the cruciate ligaments. The size and location of the ganglion cysts can attribute to the clinical manifestations.

Imaging of sports-related knee injuries

This article reviewed the major sports medicine conditions affecting the knee and their MR imaging appearance. MR imaging of the knee is considered efficacious especially in the setting of indeterminate clinical findings and can stratify patients, guiding further surgical management. MR imaging affects the diagnosis and management of acute knee injury by improving clinician diagnostic certainty, assisting in management decisions, and decreasing the number of arthroscopic procedures. From a societal perspective, knee MR imaging can be considered a cost-effective modality when compared with diagnostic and borderline therapeutic arthroscopies (e.g., debridement alone). For these and other reasons, knee MR imaging has shown a substantially increased use for the evaluation of sports medicine conditions.

MR imaging of the medial collateral ligament bursa: findings in patients and anatomic data derived from cadavers

OBJECTIVE

The purpose of this work was to define the MR imaging findings of fluid collections confined to the medial collateral ligament (MCL) bursa and to correlate these findings with anatomic features shown in cadaveric specimens.

MATERIALS AND METHODS

The anatomic location of the MCL bursa was investigated by MR-anatomic correlation in seven cadaveric knees. The MR imaging studies and clinical charts of six patients with fluid collections confined to the MCL bursa were reviewed.

RESULTS

On anatomic sections, the MCL bursa was located between the superficial and deep portions of the MCL. Separate femoral and tibial compartments were seen in most specimens.

CONCLUSION

The anatomy of the MCL bursa is shown with MR imaging in cadaveric specimens and patients. Understanding the compartmentlike distribution of fluid in the MCL bursa at MR imaging allows accurate diagnosis and differentiation from other conditions.

MR imaging of meniscal cysts: incidence, location, and clinical significance

OBJECTIVE

The purpose of this study was to determine the incidence of medial versus lateral meniscal cysts as seen on MR imaging.

MATERIALS AND METHODS

A total of 2572 knee MR imaging reports were retrospectively reviewed for the presence of meniscal tears and cysts. Two musculoskeletal radiologists reviewed all images with reported cysts. The type and location of meniscal tear and the presence and location of meniscal cysts were recorded.

RESULTS

A total of 1402 meniscal tears were reported in 2572 MR examinations (922 [66%] of 1402 in the medial compartment; 480 [34%] of 1402 in the lateral compartment). Meniscal cysts were present in 109 (4%) of 2572 knees. Of the 109 cysts, 72 (66%) were in the medial compartment, and 37 (34%) were in the lateral compartment. Meniscal cysts were found in association with 72 (7.8%) of the 922 medial meniscal tears and 37 (7.7%) of the 480 lateral meniscal tears. Meniscal cysts showed direct contact with an adjacent meniscal tear in 107 (98%) of 109 cases, with the tear showing a horizontal component in 96 (90%) of 107 cases.

CONCLUSION

Meniscal cysts occur almost twice as often in the medial compartment as in the lateral compartment. Medial and lateral tears occur with the same frequency. These findings, when viewed in the context of the historical literature on meniscal cysts, suggest that MR imaging detects a greater number of medial meniscal cysts than physical examination or arthroscopy, and that MR imaging can have an important impact on surgical treatment of patients.

MR imaging of meniscal cysts: evaluation of location and extension using a three-layer approach

PURPOSE

To analyze the extension of medial and lateral meniscal cysts relative to the capuloligamentous planes of the knee.

MATERIALS AND METHODS

The MR images of 32 patients with meniscal cysts were reviewed. The location and extension of the meniscal cysts with reference to the capsule and ligaments were recorded.

RESULTS

Most medial meniscal cysts were located posteromedially. Posteromedial meniscal cysts usually penetrated the capsule and were located between layer I and the fused layers II+III. From this site some extended anteriorly and then became located superficial to the superficial MCL. The location of lateral meniscal cysts was more varied. Anteriorly the cysts were located deep to the iliotibial band, whereas posterolateral cysts were located deep to the lateral collateral ligament.

CONCLUSION

Although the site of capsular penetration of meniscal cysts is determined by the location of meniscal tears, the possible pathways of extension appear to be determined by the capsuloligamentous planes of the knee.

Association of paralabral cysts with acetabular disorders

OBJECTIVE

Acetabular labral tears may cause considerable pain and predispose patients to premature osteoarthritis. Therefore, early and accurate examination is required. Acetabular labral tears are difficult to view on MR images. We report the association of paralabral ganglion cysts detected on MR imaging with surgically proven acetabular labral disorders.

CONCLUSION

Paralabral cysts may be associated with labral disorders. The appearance of a paralabral cyst on MR imaging is a useful indirect sign of acetabular labral abnormality. Use of this sign may enable earlier and more accurate examination of labral disorders.

Cysts and other masses about the knee: identifying and treating common and rare lesions

Masses about the knee are most commonly benign cysts. The diagnosis can often be made with a history and physical exam, but radiographs and MRI are sometimes required, and histologic evaluation is occasionally necessary. Popliteal (Baker's) cysts are often indicative of arthritis; treatment for the underlying pathology may reduce swelling and permit resorption. Meniscal cysts indicate an underlying tear; treatment is resection and cyst excision. Symptomatic ganglion cysts generally require surgical excision. Treatment for bursitis is conservative. The less-common synovial chondromatosis, pigmented villonodular synovitis, synovial sarcoma, and lesions of the proximal tibiofibular joint generally require referral and surgery.