Knee Effusion Research Articles

A RANDOMIZED CONTROLLED TRIAL TO EVALUATE THE ANTI-INFLAMMATORY EFFECT OF COMMIPHORA WIGHTII IN COMBINATION WITH CURCUMA LONGA AGAINST DICLOFENAC POTASSIUM IN NON-SPECIFIC KNEE EFFUSION

Knee effusion is an abnormal accumulation of the fluid in the knee capsule or the adjoining supra - patellar bursa secondary to the irritation/inflammation in the joint synovium. It is seen in approximately 8 - 10 % of the to tal patients suffering from osteo - arthrosis. Kro ṣṭ ukaśīr ṣ a as described in Ayurveda , can be corelated with knee effusion. In Present clinical trial an effort has been made to evaluate anti - inflammatory effect of Commiphora wightii in combination with Curcum a longa against Diclofenac potassium [NSAID’s] in Non - specific knee effusio n. Total tw enty two , clinically diagnosed patients of Non - specific knee effusion were selected for the present clinical trial excluding drop out 2 0 patients were assorted in to t wo groups Trial Group and control Groups. Trial Group 10 pa tients were given crude extract of Commiphora wightii 500 mg along with Curcuma longa 500 mg in a separate capsule twice a day continuously for 8 weeks orally . In Control Group ten patients were given Diclofenac Potassium 50 mg twice a day continuously for 2 weeks orally. It was assessed that Diclofenac potassium was significantly better in the outcomes i n comparison to the trial drugs Commiphora wightii ( Guggulu ) and Curcuma longa ( Haridra ) when compar ed at the end of two weeks of start of the trial. Trial drugs Commiphora wightii ( Guggulu) and Curcuma longa ( Haridra) are also having outcomes of comparative extent to Diclofenac Potassium w hen administered continuously for further 6 weeks i.e. total 8 we eks.

Arthroscopic Treatment of Popliteal Cyst: A Direct Posterior Portal by Inside-Out Technique for Intracystic Debridement

Popliteal cysts are characterized by enlargement of the gastrocnemius-semimembranosus bursa. The pathogenesis includes a valvular opening between the knee joint and the bursa, and associated intra-articular pathology may give rise to knee effusion. The mainstay of treatment is conservative. If popliteal cysts are symptomatic, analgesia, aspiration, and steroid injection therapy may be considered, but most recur rapidly. In the past, open excision was an option if they remained symptomatic, but the associated recurrence rate was high. One important reason was that the intra-articular pathology causing the knee effusion was not treated. We present an alternative minimally invasive arthroscopic treatment using dye (methylene blue) directly injected into the cyst, which will leak from the cyst into the joint, to identify the valvular opening. The thickened valve is opened using a basket forceps and then enlarged using a motorized shaver to disrupt the 1-way mechanism between the joint and bursa, as well as to establish an unobstructed freeway connection between them. We also present a safe technique to create a direct posterior portal. Intracystic debridement of the fibrous membrane, nodules, and septa through this portal will decrease the recurrence rate of the popliteal cyst.

Intra-articular augmentation of lubrication with silk microspheres

Purpose: Osteoarthritis of the knee represents a large unmet clinical need. Deficits in synovial lubrication have been reported in osteoarthritis, and several strategies to augment lubrication have shown preclinical benefit. We hypothesized that augmentation of the boundary lubrication of synovial fluid by intra-articular administration of long-residence non-inflammatory lubricating silk microspheres could reduce mechanical injury and pain in an osteoarthritis animal model. Methods: Silk microspheres with phospholipid coatings were prepared by a modified version of previously published methods. Osteoarthritis was induced in rats using the surgical instability model consisting of MCL tear and meniscectomy. One week following injury, affected knees were intra-articularly administered saline vehicle or silk microspheres (2.5mg). Serial body weights, knee effusion, gait analysis on Day 14, and Von Frey secondary allodynia testing on Days -1, 6, and 13 were measured. Severity of osteoarthritis was assessed by histopathologic analysis by a trained pathologist on Day 28 after injury. Results: Silk microspheres with varying size distributions were synthesized and achieved coefficients of friction approaching 0.05 to 0.02. Intra-articular injection of silk microspheres was well tolerated in rats with no adverse reactions. Von Frey testing of secondary allodynia 6 days after injection indicated a trend towards a modest but sustained reduction of osteoarthritic pain. Conclusions: Intra-articular silk microspheres offer a novel, biologically inert, non-inflammatory, and well tolerated potential therapy for osteoarthritis. These results motivate further formulation optimization of silk microsphere composition to tune synovial residence, degradation profile, lubrication properties, and potentially to provide prolonged delivery of active therapeutics. Augmentation of joint lubrication with silk microspheres merits further preclinical exploration as a novel therapy to address the unmet need in osteoarthritis.

Clinical significance of a knee effusion detected on MRI by moaks or kimriss in a patient with knee OA

Clinical significance of a knee effusion detected on MRI by moaks or kimriss in a patient with knee OA

Clinical significance of a knee effusion detected on physical examination in a patient with knee OA

Clinical significance of a knee effusion detected on physical examination in a patient with knee OA

The discovery of the synovial lymphatic stomata and lymphatic reabsorption in knee effusion.

To illustrate the mechanism of lymphatic reabsorption in knee joint effusion. The current investigation employed transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques to reveal the ultrastructure of the knee synovial membrane in New Zealand rabbits and human. Ultrastructural changes of the synovial lymphatic stomata were observed by using trypan blue absorption and sodium hydroxide (NaOH) digestion methods, and the animal models of synovitis. New Zealand rabbits and human synovial membranes were composed of two types of synovial cells: type A and type B. No lymphatic stomata were found among type A synovial cells, whereas lymphatic stomata with the diameters ranging 0.74-3.26 µm were found in type B synovial cells, and some stomata were closed. After the NaOH digestion, a number of sieve pores, similar to lymphatic stomata in size and shape, were observed in the dense fibrous connective tissue underneath the type B synovial cells. After injecting trypan blue into the rabbit knee joint cavity, absorption of trypan blue through the lymphatic stomata was observed, suggesting the absorption function of the synovial lymphatic stomata. In the rabbit knee joint synovitis models, the synovial lymphatic stomata diameter enlarged. Some macrophages migrated from the lymphatic stomata, indicating that the synovial lymphatic stomata were involved in the joint effusion absorption and inflammatory response. Our study is the first to report the existence of synovial lymphatic stomata in the New Zealand rabbits and human knee joints. Lymphatic stomata may have an important role in the reabsorption of joint effusion.

Synovial fluid and plasma n3 long chain polyunsaturated fatty acids in patients with inflammatory arthritis

Relationships between n-3 long chain polyunsaturated fatty acids (LC-PUFA) in plasma and synovial fluid (SF) were examined in 36 patients with knee effusion within the context of a variety of rheumatic diagnoses and various stated fish oil (FO) intakes (from 0 to 30mL of standard FO daily) of variable duration. In a sub-group of patients, correlations between PUFA in SF mononuclear cells (MNC) and cell-free supernatants of SF and between SF MNC and peripheral blood (PB) MNC were examined. Correlations were also sought between clinical data (stated FO intake, pain score) and n-3 LC-PUFA.Correlations between plasma n-3 LC-PUFA and SF n-3 LC-PUFA were very strong (r2>0.9, p<0.001). The LC-PUFA profiles of SF supernatants differed from those of MNC. PUFA profiles in PB MNC and SF MNC were similar, except for a higher proportion of DHA in the latter. Positive correlations were observed between stated intakes of FO and EPA in plasma and SF (for both r=0.37, p=0.02) and DHA in plasma (r=0.37, p=0.02) and SF (r=0.36, p=0.03). n-3 LC-PUFA in plasma and SF correlated inversely with pain score (plasma r2=0.16, p<0.02; SF r2 0.32, p=0.001).In conclusion, plasma n-3 LC-PUFA is a strong indicator of SF n-3 LC-PUFA status across a broad range of rheumatic diagnoses and FO intakes. Higher n-3 LC-PUFA in plasma and SF were associated with lesser pain experience.

Correlation between synovial vascular endothelial growth factor, clinical, functional and radiological manifestations in knee osteoarthritis

Aim of the workTo correlate between synovial vascular endothelial growth factor (VEGF), clinical, functional and radiological findings in knee osteoarthritis (KOA) patients. Patients and methodsTwenty patients with primary KOA were clinically examined and the modified Ritchie articular index (RAI) recorded. The knees were examined and knee pain evaluated by the visual analog scale (VAS) and tenderness by the knee subscale of the RAI. The Western Ontario Mc Master scale (WOMAC) was recorded and the Kellgren–Lawrence grading used to assess radiographic severity. The synovial level of VEGF was assessed using ELISA. ResultsThe mean age was 56.15±7.77years and body mass index 28.1±4.04. All patients had knee effusion; 40% were bilateral and 60% unilateral. The mean duration of knee pain was 3.01±1.43years; duration of morning stiffness was 15.75±3.72min. The mean WOMAC was 44.22±11.46 and modified RAI 5.45±2.94. The mean knee subscale of RAI was 2.9±1.16 and VAS for knee pain 5.7±2.92. The mean synovial VEGF level was 693.71±314.63pg/ml. There was a significant increase in the synovial VEGF compared to the reference value (p=0.0001). There was a significant correlation between the synovial VEGF and patients’ age (p=0.04), knee pain duration (p=0.025), morning stiffness (p<0.0001), modified RAI (p=0.0001), knee subscale of RAI (p<0.0001), VAS for knee pain (p<0.0001) and WOMAC (p=0.0001). There was a significant negative correlation between synovial VEGF and muscle strength grading (p=0.0001) and a significant correlation with the radiological assessment (p=0.0001). ConclusionSynovial VEGF significantly correlated with clinical manifestations, functional impact, as well as radiological changes of KOA.

Effect of drainage tube on muscle strength &amp; knee function after arthroscopically assisted anterior cruciate ligament reconstruction

Background: There is a paucity of literature evaluating the use of intra-articular drains after arthroscopic procedures. The aim of this study is to determine the effect of postoperative drain use on muscle strength and knee function after arthroscopically assisted anterior cruciate ligament (ACL) reconstruction with quadrupled hamstring graft. Method: 44 arthroscopic ACL reconstruction patients were randomized for either intra-articular suction drain group or non-drain group. All arthroscopic ACL reconstructions using a four strands hamstrings graft as auto graft were included in the trial. Assessment was done on postoperative day 4, day10, 1 month, 3, 6 and 12 months after the surgery in which patients were asked to complete a visual analogue pain scale, were assessed for range of motion, knee effusion, measurement of quadriceps and hamstrings using dynamometer. Result: Comparison of quadriceps strength between the two groups showed no statistical significant difference at 30 degrees. (p <0.167) and 90 degrees (0.115) of knee flexion. Statistically significant difference was seen at 60 degrees knee flexion. (p = 0.036). Both groups showed no statistical significant difference in knee flexion. (p = 0.116) The reduction in knee effusion was found to be statistically significant at 4th (p <0.001), 10th (p <0.001)16 and one month (p = 0.012) ) in between treatment and control group. The overall pain difference between the two groups was not found to be statistically significant. (p = 0.198) Conclusion: This study showed that following surgery, clinically the increment in the muscle strength was more in the drain group compared to the no drain group but was statistically significant only for quadriceps at 60 degree flexion in drain group. Clinically the drain group showed faster pain relief, lesser effusion and early return to motion compared to the no drain group.

The effect of intra-articular Tenoxicam on knee effusion after arthroscopy.

NSAIDs and analgesic drugs are used intra-articularly after knee arthroscopy for pain relief. However, synovial effusion is still a common cause of delayed physical therapy. The aim of this study was to demonstrate the beneficial effect of intra-articular injection of Tenoxicam on knee effusion after arthroscopy. This was a prospective non-randomized study on 134 patients with a mean age of 36.7 years. Knee arthroscopy on a day-case basis was performed; normal saline was used for irrigation. At the end of the procedure, fluid was aspirated from the knee joint and 20 ml of Tenoxicam diluted with 20 ml of 0.9% normal saline was injected into the knee five minutes before deflation of limb tourniquet. The same surgeon performed clinical examination for knee effusion 14 days postoperatively. Encountered pathologies included meniscal injury, degenerative arthropathy, synovial plica and ACL rupture. Knee effusion developed in 15.7% of the patients, particularly in those with degenerative arthropathy (p = 0.006) and meniscal lesions (p = 0.06). Intra-articular Tenoxicam is a simple method for the prevention of postoperative knee effusion. Degenerative arthropathy and meniscal lesions are major risk factors for post arthroscopy knee effusion.

Pseudogout at the knee joint will frequently occur after hip fracture and lead to the knee pain in the early postoperative period.

BackgroundSymptomatic knee joint effusion is frequently observed after hip fracture, which may lead to postoperative knee pain during rehabilitation after hip fracture surgery. However, unfortunately, very little has been reported on this phenomenon in the literature. The purpose of the current study was to investigate the relationship between symptomatic knee effusion and postoperative knee pain and to clarify the reason of the effusion accompanied by hip fracture.MethodsA total of 100 patients over 65 years of age with an acute hip fracture after fall were prospectively followed up. Knee effusion was assessed on admission and at the operating room before the surgery. If knee effusion was observed at the time of the surgery, synovial fluid was collected into syringes to investigate the cause of the effusion using a compensated polarized light microscope. Furthermore, for each patient, we evaluated age, sex, radiographic knee osteoarthritis (OA), type of the fracture, laterality, severity of the fracture, and postoperative knee pain during rehabilitation. These factors were compared between patients with and without knee effusion at the time of the surgery. As a statistical analysis, we used Mann–Whitney U-test for patients’ age and categorical variables were analyzed by chi-square test or Fisher’s exact test.ResultsA total of 30 patients presented symptomatic knee effusion at the time of the surgery. In patients with knee effusion, numbers of intertrochanteric fracture, radiographic knee OA, and postoperative knee pain were significantly large compared to those without effusion. In terms of synovial fluid analysis, calcium pyrophosphate dihydrate crystals were observed in 80% of patients with knee effusion.ConclusionFrom our study, approximately 63% of patients with knee effusion at the time of the surgery had postoperative knee pain. In addition, this effusion was basically related to pseudogout.

A Prospective Study on Inflammatory Cytokines and Bone Metabolism Mediators in Patients Affected by Rheumatoid and Psoriatic Arthritis treated with Adalimumab

Rheumatoid (RA) and Psoriatic arthritis (PsA) are characterized by extensive synovitis resulting in bone destruction in both diseases and new bone formation in PsA. Objective: This prospective study analyzed interleukin (IL)-6, IL-17, IL-23, tumor necrosis factor (TNF)-α serum and synovial fluid (SF) levels and osteoprotegerin (OPG), bone-specific alkaline phosphatase (BAP) and D-vitamin (D-Vit) serum levels in RA and PsA patients before and after anti-TNF-α. Methods: 15 RA and 15 PsA patients with knee effusion and starting adalimumab (ADA) treatment were enrolled. Serum and SF from inflamed knee joint samples were obtained at baseline and after 24 weeks of treatment. Statistical analysis was performed using Graph Pad 5.0 statistical software. Results: In RA and PsA, SF IL-6, IL-17, and TNF-α were higher than serum levels while higher serum IL-23 was detected than in SF. Higher serum/SF IL-6, IL-23 and SF TNF-α were observed in RA than PsA, while serum IL-17 was higher in PsA than RA. Positive feedback among IL-6, IL-23, IL-17 and CRP and negative correlation between IL-17 and TNF-α in RA were found. In PsA, IL-23 correlated positively with IL-6. OPG correlated positively with ESR/CRP in RA and PsA. D-Vit correlated negatively with OPG and ESR in PsA. Higher BAP in RA than PsA and positive correlation with IL-6 in RA and with OPG in PsA were noticed. In PsA, IL-6 and OPG serum levels decreased significantly after 24 weeks ADA treatment. Conclusions: Distinct distribution of inflammatory cytokines and correlations with bone mediators were detected in RA and PsA. ADA affected inflammatory cytokines and bone mediators in PsA patients.

Glanzmann's Thrombasthenia Diagnosed following Knee Arthroscopy.

A 41-year-old man with an unremarkable medical history presented with a painful knee after a sports injury. He was diagnosed with a medial meniscal tear. Symptoms did not abate after 6 months of physical therapy, and he underwent arthroscopic partial medial meniscectomy. A week after beginning physical therapy he experienced a knee effusion, decreased ROM, and inability to flex his quadriceps. His knee was aspirated. Blood tests were ordered and his complete blood count, liver functions tests, and INR/PTT were normal. The patient had recurrent effusions requiring three additional joint aspirations. Ten weeks after the initial surgery, the patient underwent a second arthroscopy, during which a hematoma was removed and a synovectomy performed. The patient continued bleeding from the incisions after portals were sutured, and he was admitted to the hospital. A hematologist was consulted and comprehensive platelet aggregation testing revealed previously undiagnosed Glanzmann's thrombasthenia. The patient began treatment with platelet infusions and desmopressin and progressed to a full recovery. Clinical suspicion for surgical patients with unusual repetitive postoperative bleeding should include previously undetected rare bleeding disorders even in adults.

Effect of Combined Balance and Isotonic Resistive Exercises Versus Isotonic Resistive Exercise alone on Proprioception and Stabilizing Reactions of Quadriceps and Hamstrings and Functional Capacity of Knee Osteoarthritis Patients

Objectives: To compare the effect of combined balance and dynamic resistive exercise versus dynamic resistive exercise alone on proprioception and stabilizing actions of the quadriceps and hamstrings and functional capacities in patients with knee osteoarthritis. Design: Randomized clinical trial. Participants: Fifty nine patients with knee osteoarthritis randomized to group I (resistive exercise) (n=21) and group II (combined resistive +balance exercise) n=38. Intervention: All patients had electrotherapy, flexibility and resistive exercises for the legs, 3 times weekly for 8 weeks. Group II also added balance exercises. Main outcome measures: Knee examination, knee pain by visual analogue scale, Lequesne index, one repetition maximum for quadriceps, body mass index, recording of postural evoked surface EMG for quadriceps and hamstrings, and measurement of knee proprioception inaccuracy. Results: Knee effusion improved in both groups with significantly higher improvement in group II (P=0.017). Knee pain significantly decreased in both groups with higher mean percent change in group II (-50.9 ± 29.59) than in group I (-41.2± 10.89) with no significant difference in between groups (P=0.48). Lequesne score significantly decreased in both groups without difference in between groups (P value within groups =0.000). One repetition maximum for quadriceps significantly increased in both groups with higher mean percent change in group II (50.43 ± 16.6) than in group I (47.02 ± 41.97) (P value within group =0.000, P in-between groups=0.64). There were limited significant changes of quadriceps and hamstring reflex EMG in both groups. There were significant improvements of knee joint proprioception inaccuracy at the three measured angles 10, 30, 60 in both groups. However the mean percentage of changes was higher in group II than in group I at the measured angle 10 and 30. Group I had significantly higher improvement at angle 60. Conclusion: Balance exercises add to the benefits of resistive exercise to knee osteoarthritis patients.

Lateral versus medial approach for intra-articular knee injections.

The aim of this study was to determine whether the medial or the lateral mid-patellar approach is the most reliable for intra-articular knee injections. The study included 76 knees of 76 patients divided into 2 groups. The first group consisted of 38 patients with a knee injury and resultant knee effusion. The second group included 38 patients without any known knee pathology. Patients were matched according to age and gender. The medial joint opening (medial patellofemoral angle) was calculated on a T1-weighted transverse image by measuring the anatomic angle between the femur and the patella. The lateral joint opening (lateral patellofemoral angle) was calculated in a similar way. The medial patellofemoral angle was significantly higher than the lateral patellofemoral angle in both groups (p<0.001). The medial patellofemoral angle is significantly higher than the lateral patellofemoral angle in both healthy knees and knees with effusion. Therefore, the medial approach appears to be more accurate for intra-articular knee injection due to the medial joint's larger opening.

MONOARTICULAR SYNOVITIS OF KNEE DUE TO UNRECOGNISED INTRA-ARTICULAR PLANT SPLINTER

AbstractSynovitis of a knee secondary to penetrating splinter injuries of plant origin aren't frequently reported. Historically, it is considered aseptic and treated with removal of the intraarticular foreign body and affected synovial lining.We report a case of a 59-year-old healthy man whose left knee was injured while at work at a bamboo plantation site. He presented to us with pain and swelling of the knee for one month. He underwent diagnostic arthroscopy of the knee wherein a foreign body was identified, located and removed and near total synovectomy was done.We present this patient's case and its management with a review of the relevant literature.

A Rare Intra-articular Pathology of Knee Lipoma Arborescens: A Report of Two Cases Managed by Arthroscopic Synovectomy: 膝關節罕見的關節內病變--樹枝狀脂肪瘤：由關節鏡滑膜切除術醫治的兩個病例報告

Lipoma arborescens is a rare intra-articular condition of unknown exact aetiology. Lipoma arborescens is one of the differential diagnoses of diffuse chronic swelling of the knee and its magnetic resonance imaging (MRI) appearance is diagnostic. We present two cases of patients with recurrent knee effusion. MRI showed a frond-like fatty synovial mass and joint effusion that suggested the likelihood of lipoma arborescens. Arthroscopic synovectomy was performed and pathology confirmed the diagnosis. There was no recurrence of symptoms after synovectomy.

No clinical benefit of titanium nitride coating in cementless mobile-bearing total knee arthroplasty.

Titanium nitride (TiN) coating of cobalt-chromium-molybdenum (CoCrMo) implants has shown to improve the biomechanical properties of the implant surface and to reduce adhesive wear in vitro. It is yet unknown whether TiN coating of total knee prosthesis (TKP) affects the postoperative clinical outcome of total knee arthroplasty (TKA). In a double-blind randomized controlled clinical trial, 101 patients received an uncemented mobile-bearing CoCrMo TKP, either TiN coated or uncoated. Primary outcome measure visual analogue scale (VAS) score for pain, and secondary outcome measures Knee Society Score (KSS), revision rate and adverse events, range of motion of the knee as well as knee circumference and knee skin temperature were assessed 6 weeks, 6 months, 1 year and 5 years postoperative. Repeated measures analysis was used to evaluate the postoperative outcome measures over time. There was no difference between the two groups in VAS score, KSS, revision rate, range of motion of the knee, knee circumference and knee skin temperature. There were no adverse events that could be related to the TiN coating. TiN-coated TKP does not influence the postoperative outcome of uncemented mobile-bearing TKA regarding postoperative pain, revision rate, range of motion, swelling and temperature of the knee. Therefore, TiN coating of CoCrMo TKP has no clinical benefit on the outcome of cementless mobile-bearing TKA. Therapeutic study, Level I.

Comparison of Arthroscopic, Radioactive and Combined Synovectomy in the Treatment of Chronic Non-Specific Knee Synovitis

Objective: To compare the outcomes of arthroscopic, radioactive and combined synovectomies in patients with chronic non-specific recurrent synovitis who did not respond to conservative therapy. Subjects and Methods: Twenty-nine patients enrolled between 2007 and 2011 were divided into 3 groups: group 1 was treated with arthroscopy, group 2 received a radioactive drug and group 3 received a combined (radioactive and arthroscopic) synovectomy. Treatment efficacy was evaluated by comparing pre- and post-operative Lysholm knee scores (LKS), night pain, resting pain, activity pain and effusions using visual analogue scales (VAS). Patient satisfaction was assessed using the visual analogue patient satisfaction scale (VAPSS). Results: The mean age of the study participants was 41.5 ± 5.2 years (range 14-76), and the mean follow-up period was 33.6 ± 3.2 months (range 17-78). Before treatment, the mean LKS was 41.4 ± 3.4 in group 1, 39.6 ± 3.3 in group 2 and 37.1 ± 4.6 in group 3. After treatment, the corresponding mean LKS were 77.7 ± 2.1, 81.6 ± 2.8 and 91.3 ± 2.7 in groups 1, 2 and 3, respectively; the increase was statistically significant (p < 0.05). The VAS scores before and after treatment decreased significantly (p < 0.05). The mean VAPSS score, a measure of patient satisfaction, was 5.1 ± 1.7, 5.8 ± 1.5 and 7.4 ± 1.8 in groups 1, 2 and 3, respectively, and the difference between groups 1 and 2 was not statistically significant, while that between group 3 and the other two groups was significant (p < 0.05). Conclusion: This study showed that the three methods used in individuals with chronic non-specific recurrent synovitis were effective; however, arthroscopic synovectomy in combination with radioactive synovectomy was more effective than the other methods and superior in terms of patient satisfaction.

Radiographic Evaluation of Transient Lateral Patellar Dislocation

Transient lateral patellar dislocation is a commonly encountered injury. It presents a challenge to the radiologist due to the difficulty with making the correct diagnosis on radiography. The MR findings of acute transient lateral patellar dislocation have been well described1–3 and include rupture of the medial patellofemoral ligament, large knee effusion, “kissing bone contusions” in the medial facet of the patella and lateral aspect of the lateral femoral condyle, lateral patellar tilt or subluxation, osteochondral fracture of the patella and/or the lateral femoral condyle, and intra-articular bony fragment. There is only one report in the literature on the radiographic diagnosis of transient lateral patellar dislocation.4 Diagnosing transient lateral patellar dislocation on radiography is challenging because its imaging features on radiography are subtle. Looking for these small findings is similar to looking at the tip of an iceberg: The small visible tip at the surface harbors serious danger down below! This CME article reviews the salient aspects of transient lateral patellar dislocation relevant to daily radiology practice.