Kaushal Mehta

The Role of Imaging in Diagnosing Diseases of the Distal Radioulnar Joint, Triangular Fibrocartilage Complex, and Distal Ulna

OBJECTIVE The purpose of this article is to review the anatomy, biomechanics, and multimodality imaging findings of common and uncommon distal radioulnar joint (DRUJ), triangular fibrocartilage complex, and distal ulna abnormalities. CONCLUSION The DRUJ is a common site for acute and chronic injuries and is frequently imaged to evaluate chronic wrist pain, forearm dysfunction, and traumatic forearm injury. Given the complex anatomy of the wrist, the radiologist plays a vital role in the diagnosis of wrist pain and dysfunction.

Patellotibial contusions in anterior cruciate ligament tears.

Bone contusions are an important ancillary finding of many knee injuries. Not only are they a source of pain, they may suggest a mechanism of injury or a specific derangement of the knee joint. We have encountered a small number of patients being evaluated for anterior cruciate ligament (ACL) tears with unexplained patellar and tibial edema at magnetic resonance (MR) imaging. We present three individuals with contusions of the inferior patella with a corresponding contusion of the anteromedial tibial plateau. Internal derangements in these patients were similar to other individuals with acute ACL tears, however osseous contusions were more widespread. In conclusion, patellotibial contusions are rare and may indicate an injury with forces greater than usually encountered in most ACL tears. A careful search for uncommon associated injuries is prudent in these high-energy knee injuries.

Superolateral Hoffa's Fat Pad Edema in Collegiate Volleyball Players.

Objective Superolateral Hoffas fat pad (SHFP) edema is a previously described magnetic resonance (MR) finding located between the patellar tendon and the lateral femoral condyle. The purpose of our study was to determine the prevalence and clinical significance of SHFP edema in female collegiate volleyball players. Materials and Methods Sixteen female collegiate volleyball players were consented for bilateral knee evaluations which consisted of history, physical examination and MR imaging. Each MR study was reviewed for the presence of SHFP edema, and 6 patellar maltracking measurements were done. These were tibial tuberosity-trochlear groove distance, patellar translation, lateral patellofemoral angle, trochlear depth, trochlear sulcus angle, and lateral trochlear inclination angle. Results A total of 16 athletes, 32 knees (16 girls; age range, 18–22 years; mean, 19.9) were enrolled in the study. Sixteen knees (50%) in 8 athletes had SHFP edema, with 100% bilaterality; 16 knees in 8 athletes had no evidence of SHFP edema (50%). Functional outcomes and physical examination findings were within normal limits for all athletes with no difference noted between SHFP edema-positive and -negative individuals. There was a statistically significant difference in the tibial tuberosity-trochlear groove distance, patellar translation, and patellofemoral angle (P value of < 0.001, 0.03 and 0.01, respectively) between the SHFP edema-positive and -negative individuals. Conclusions Elite female volleyball athletes have a very high prevalence of SHFP edema, which is always bilateral. Although the exact etiology of SHFP edema remains inconclusive, it could potentially be a sensitive indicator of subtle patellar maltracking which cannot be distinguished by history and physical examination findings. Given the very high prevalence of SHFP edema and this being an asymptomatic finding, there is likely little clinical significance of this in majority of high-performance athletes.

Stress injury of the rib in a swimmer

Rib stress injuries are uncommonly reported but have been documented among athletes, most notably rowers. There have only been two prior case reports of rib stress injuries in swimmers, both of which were young females. Magnetic resonance (MR) imaging was either not obtained or the imaging characteristics were incompletely described. We present a case of an isolated third rib stress injury in a collegiate male swimmer diagnosed via MR imaging. We briefly discuss the possible etiologies for rib stress injuries, their MR appearance, as well as their treatment.

Cysts of the anterior horn lateral meniscus and the ACL: is there a relationship?

ObjectiveParameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM). The common insertion of the anterior cruciate ligament (ACL) and the AHLM root may provide a pathway for disease. The purpose of our study was to determine if cysts of the ACL are the origin of cysts adjacent to the AHLM.Materials and methodsRadiology reports of all magnetic resonance (MR) examinations of the knee over a 7-year period were searched for “cyst”, “ganglion”, and “ganglia”. Two fellowship-trained musculoskeletal radiologists independently reviewed those MR examinations reported to have a possible cyst of the AHLM and/or the ACL. The study group consisted of those patients with a cyst located adjacent to the AHLM but no meniscal tear of the adjacent meniscus. The ACL in each of these patients was evaluated for the presence of a cyst. Comparison with age- and gender-matched controls was performed.ResultsOf 708 cases that contained the word “cyst”, “ganglion”, or “ganglia”, 121 reports indicated a possible cyst of the ACL or AHLM. Twelve individuals had a cyst located adjacent to the AHLM with no meniscal tear. Six (50%) of these individuals had a cyst of the ACL; no ACL cysts were identified in the control group (p = 0.014). Interreader agreement for AHLM parameniscal cysts and AHLM tears was substantial.ConclusionsOur results suggest that cysts adjacent to the AHLM may in part be explained by cysts or ganglia of the ACL.

The anteromedial tibial rim sign: an indicator of patellotibial impaction in acute anterior cruciate ligament tears.

Objective We have encountered unexplained anteromedial tibial rim edema in acute anterior cruciate ligament (ACL) tears. Our goal was to determine the incidence, internal derangements, and mechanism of injury in patients with anteromedial tibial rim edema (rim sign). Materials and Methods A retrospective review of ACL tears diagnosed by magnetic resonance imaging over 7 years was performed. Patients were dichotomized into those with and without a rim sign. Results There were 132 acute ACL tears. Individuals with a rim sign (31, 23%) had more contusions, fractures, ligament tears (P < 0.001), posterolateral corner injuries (P = 0.001), and posterior horn lateral meniscus tears (P = 0.042) than those without. Five individuals demonstrated edema in the inferior patella, consistent with patellotibial impaction. Conclusions The rim sign is common in ACL tears, indicating greater internal derangement. The rim sign represents patellotibial impaction with edema rarely present in the patella.

Patellotibial contusions: a rare cruciate ligament injury pattern.

Objective Patellotibial contusions are a recently described contusion pattern in anterior cruciate ligament (ACL) tears. The purposes or our study were to determine if patellotibial contusions are specific to ACL injuries, determine the internal derangements in patients demonstrating this contusion, and suggest a mechanism of injury. Materials and Methods We conducted a retrospective search of radiology reports over a 6-year period to identify patients with patellar edema described on magnetic resonance (MR) imaging. Only individuals with patellar and tibial edema were included in the study group. These MR examinations were then reviewed for associated internal derangements. Results From March 2007 to June 2013, 1914 MR examinations of the knee were performed. Two hundred seventy-one reports described patellar edema. Seven individuals had edema of both the inferior pole of the patella and the anterior tibial plateau. Three individuals were involved in motor vehicle accidents (MVAs); 4 patients had a history of an axial load or sports-related injury. All 3 patients involved in MVAs had posterior cruciate ligament tears consistent with posterior translation of the tibia. The non-MVA individuals had tears of the ACL with internal derangements similar to other ACL deficient knees, however, with more widespread osseous contusions. Conclusions Patellotibial contusions are high-energy injuries resulting in cruciate ligament tears. These contusions occur exclusively in patients with ACL tears when individuals with a history of direct impaction to the knee are excluded. Axial loading of the extended knee may be an important mechanism of injury in these individuals.

The trochlear cleft: initial experience in elite athletes.

Objective The trochlear cleft is a recently described vertically oriented, low-signal cartilage lesion centered in the trough of the trochlear cartilage. The purpose of our study was to determine the incidence of clefts in an at-risk group of athletes and correlate these findings with clinical and physical examination results. Materials and Methods Sixteen female collegiate volleyball players consented to bilateral knee evaluations, which consisted of history, physical examination, and magnetic resonance (MR) imaging. Two fellowship-trained musculoskeletal radiologists reviewed each MR study by consensus. The trochlear cartilage was considered to be either normal, at risk of developing a cleft, or meeting the previously described criteria for clefts. The Fisher exact test was used for categorical variables, and the Mann-Whitney U test was used for nonparametric continuous variable. Results A total of 16 athletes (32 knees; 16 women; age range, 18–22 years; mean, 19.9 years) were enrolled in the study. Four knees (13%) in 3 athletes were diagnosed with a trochlear cleft; 6 knees (19%) in 4 athletes had clefts or were at risk of developing clefts. Among those players with unilateral cartilage lesions, 67% had contralateral abnormalities (P = 0.0783). Functional outcomes and physical examination findings were within normal limits for all athletes, with no difference noted between those with and without clefts. Conclusions Elite athletes have a much higher incidence of trochlear clefts than the general population and are at risk of bilateral disease. Clefts are likely to be an incidental finding at MR imaging for unrelated symptoms.