The deep medial femoral sulcus sign: does it exist?

OBJECTIVE: To determine the normal depth of the medial femoral sulcus on lateral radiographs of the knee and determine if abnormal deepening of the medial femoral sulcus exists as a radiographic indicator of intra-articular knee abnormalities. MATERIALS AND METHODS: A retrospective search was performed over a period of 10 years to identify all individuals with a bone contusion of the anterior medial femoral condyle at MR imaging. Study patients had documented acute knee injuries and radiographs 6 weeks or less prior to their MR. A control group had normal MR exams and radiographs 6 weeks or less prior to their MR. Two fellowship-trained musculoskeletal radiologists independently measured the depth of the medial femoral sulcus on lateral radiographs blinded to control or study individuals. RESULTS: The study group consisted of 76 patients (57 men, 19 women; age range, 18-50 years; mean age, 27 years) and 92 control patients (33 men, 59 women; age range, 18-46 years; mean age 26 years). Sulcus depth was (0-2.3 mm reader 1 and 0-1.7 mm reader 2 for controls; 0-2.2 mm reader1 and 0-1.8 mm reader 2 for study patients). No significant difference in sulcus depth was identified between the control and study groups. Inter-reader agreement was very strong. The most common cause of injury in the study group was motor vehicle accidents followed by hyperextension and twisting injuries of the knee. CONCLUSION: The normal medial femoral sulcus ranges in depth from 0 to 2.3 mm. Although impaction of the sulcus does occur following knee injuries, the sulcus does not deepen.

Friction Syndromes of the Knee: The Iliotibial Band and Anterior Fat Pads.

As participation in sporting activities increases among the general population, the incidence of overuse injuries continues to rise. Friction syndromes of the knee are common and are often clinically diagnosed without the need for imaging. However, clinical symptoms may overlap with other joint abnormalities, and physical examination may be limited in individuals with excessive pain. Magnetic resonance imaging has remained the modality of choice for the evaluation of internal derangements of the joints and is a useful aid in the diagnosis of friction syndrome of the knee. This case report provides clinicians with an understanding of the most common friction syndromes of the knee joint as well as their imaging findings. (Journal of Surgical Orthopaedic Advances 27(1):77-80, 2018).

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.

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

OBJECTIVE: Superolateral Hoffa's 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.

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

OBJECTIVE: Parameniscal 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 METHODS: Radiology 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. RESULTS: Of 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. CONCLUSIONS: Our results suggest that cysts adjacent to the AHLM may in part be explained by cysts or ganglia of the ACL.

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: 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.

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.

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.

Outcomes following open acetabular labrum reconstruction: Comparing fresh-frozen tendon with fresh meniscus allograft transplantation.

Background: Symptomatic acetabular labral insufficiency in young, active patients is often treated with labral repair or reconstruction using fresh-frozen allografts. However, fresh-frozen tendon allografts do not have tissue or material properties that closely mimic acetabular labral fibrocartilage. Recent studies suggest meniscal allografts may be a better biomechanical, geometric, and material alternative for acetabular labrum reconstruction (ALR). Hypothesis: Patients undergoing open ALR using fresh meniscus allograft transplants (MAT) will have better outcomes than those using fresh-frozen tendon allografts transplants (TAT) when comparing initial treatment success, diagnostic imaging assessments, and patient-reported pain and function scores. Study design: Cohort Study. Methods: With IRB approval, patients undergoing ALR with either TAT or MAT were included when initial (>1-year) outcomes data related to treatment success, pain, and function were available. In addition, a subcohort of patients underwent magnetic resonance imaging at least 6-months after surgery to evaluate allograft healing. Results: Initial success rate, defined as no need for ALR revision or conversion to total hip arthroplasty (THA), was 88.9% for the entire group (n = 27, TAT = 5, MAT = 22) with 1 (20%) patient in the TAT cohort and 2 patients (9.9%) in the MAT cohort undergoing THA. In the MAT cohort, significant improvements were documented for physical function and pain scores at 1 year and final follow-up (FFU)(mean 26.8 months). Improvements in pain and function were noted at 1-year, but not at FFU (mean 59.6 months) in the TAT group. MRIs completed at least 6 months after labrum reconstruction showed improved allograft integrity and integration in the MAT cohort over the TAT cohort. Conclusion: For acetabular labrum reconstructions, MAT was associated with a higher initial success rate, superior patient reported outcomes, and subjectively better MRI findings when compared to TAT.

Post-traumatic pseudoaneurysm of the thyrocervical trunk.

Pseudoaneurysms of the thyrocervical trunk or its branches are extremely rare. They are often the result of a penetrating injury and commonly iatrogenic in origin. Pseudoaneurysm formation following blunt trauma has twice been reported in the English-language literature. We report a case of a 56-year-old man involved in a motor vehicle collision who presented with a slowly growing mass over the course of 4 months. A magnetic resonance (MR) examination was requested to evaluate the cause of this slowly growing mass. Our case is unique in that MR imaging correctly diagnosed the lesion, which was subsequently treated with ultrasound-guided percutaneous thrombin injection. Our case is the only published instance of treatment of a thyrocervical trunk pseudoaneurysm by direct ultrasound-guided percutaneous thrombin injection.

Percutaneous balloon humeroplasty for Hill-Sachs lesions: a novel technique.

INTRODUCTION: Hills-Sachs lesions are commonly associated with anterior shoulder dislocations and can be a source of recurrent instability. Studies have shown that, even after soft tissue repair of a Bankart lesion, there is still a risk for redislocation in a patient with significant bony defects. The purpose of this study is to ascertain whether balloon humeroplasty is an effective technique of reducing acute Hill-Sachs defect in a cadaveric model. METHODS: Eighteen cadaveric humerii dissected free of soft tissue were used for this study. Hill-Sachs lesions were created in a reproducible manner in the anatomical posterolateral aspect of the head with a mallet edge. An inflatable balloon tamp (balloon, IBT) was used to reduce the lesion via a small transcortical window. Cement was used to fill the void created by the balloon. We utilized computed tomography (CT) to collect volume data of each humeral head pre- and post-procedure. From this data, we calculated the volume of the Hill-Sachs defect and the percent corrected. A paired t test was performed to analyze the data statistically. RESULTS: The average prereduction Hill-Sachs defect volume was 1515.5 mm(3). The average post-reduction lesion residual volume was 31 mm(3) with 99.3% reduction to the original humeral head volume. The Hill-Sachs lesion reduction was statistically significant with P value of .0004. CONCLUSION: Balloon humeroplasty proved to be an effective technique for reducing Hill-Sachs lesions in a cadaveric model. This technique may be used as an adjunct to arthroscopic versus open Bankart procedure for engaging acute Hill-Sachs lesions.

Initial Validation of a Modified MRI Scoring System for Assessing Outcomes after Single-Surface Osteochondral Shell Allograft Transplantation in the Knee.

The Osteochondral Allograft Magnetic Resonance Imaging Scoring System (OCAMRISS) provides a reproducible method for imaging-based grading for osteochondral allograft (OCA) transplants. However, the OCAMRISS does not account for larger whole-surface OCA shell grafts, and has not been validated for assessing outcomes after shell OCA transplantation. Therefore, the objective of this study was to evaluate a modified OCAMRISS for assessing single-surface shell OCAs in the knee based on strength of correlations for a modified OCAMRISS score with graft success and patient-reported outcomes for pain and function. With institutional review board approval and informed patient consent, patients who underwent large single-surface shell OCA transplantation and magnetic resonance imaging (MRI) exams at 1-year postsurgery were identified from a prospectively enrolled registry. All patients with a minimum of 2 years of clinical follow-up were included in the present study. A modified OCAMRISS, as well as assessment of the percentage of OCA bone incorporation, was used to score each knee. Two radiologists, blinded to patient demographics and outcomes, reviewed all MRIs together to determine a consensus score for each category and %-incorporation for each OCA. Thirteen patients (7 F, 6 M; mean age = 29.8 ± 9.4; mean body mass index = 27.1 ± 5.8); 8 medial femoral condyle, 4 patella, and 1 medial tibial plateau shell OCAs were evaluated. Mean modified OCAMRISS score was 5.2 ± 2.8, range (2-12) and %-integration was 72.7 ± 33.8, range (0-100). Moderate to strong correlations were noted for 1-year modified OCAMRISS total score with final follow-up (FFU) visual analog scale (VAS) pain (r = +0.58) and Single Assessment Numeric Evaluation (SANE) function (r = -0.7) scores, and for 1-year %-incorporation with FFU VAS pain (r = -0.76) and SANE function (r = +0.83) scores. The modified OCAMRISS total score and %-incorporation assessments determined at 1 year following single-surface shell OCA transplantation correlate well with initial patient outcomes and have clinical applicability for monitoring patients after large-shell OCA transplants in the knee.

Cysts within and adjacent to the lesser tuberosity: correlation with shoulder arthroscopy.

OBJECTIVE: The purpose of our study was to determine if cysts in and adjacent to the lesser tuberosity are associated with rotator cuff pathology found at arthroscopy. MATERIALS AND METHODS: A retrospective review was undertaken of the magnetic resonance (MR) imaging of 286 consecutive arthroscopic procedures performed by a single orthopedic shoulder surgeon from February 2001 to June 2009. Images of the shoulders were reviewed by an experienced fellowship-trained musculoskeletal radiologist, reader 1, and a musculoskeletal fellow, reader 2, for the presence and location of lesser tuberosity cysts. Cysts were grouped by their location into those within the lesser tuberosity and those adjacent to the lesser tuberosity. Interreader agreement was calculated using kappa values. RESULTS: A total of 26 patients (17 men, 9 women; age range 14­84 years; mean of 61 years) had cysts in or adjacent to the lesser tuberosity. For reader 1, patients with cysts located in the lesser tuberosity were found to be significantly older(p=00.03) and more likely to have subscapularis tendon tears(p=00.02) than patients with cysts located adjacent to the tuberosity. No significant difference in any category between patients with a cyst located in the lesser tuberosity and those adjacent to the tuberosity was identified for reader 2. Interreader agreement of imaging findings ranged from fair to near perfect agreement. CONCLUSION: Cysts located in the lesser tuberosity at the insertion of the subscapularis tendon are suggestive of subscapularis tendon pathology and may occur in older individuals.

The trochlear cleft: the "black line" of the trochlear trough.

OBJECTIVE: The "cartilage black line sign" is a recently described T2 dark cartilage lesion that we have identified appearing as a cleft in the trochlear trough. The purpose of our study was to define the MR imaging characteristics of a trochlear cleft, determine its incidence, and correlate the MR findings with arthroscopy. MATERIALS AND METHODS: A total of 1,300 consecutive MR examinations of the knee were retrospectively reviewed by consensus of two fellowship-trained musculoskeletal radiologists. The MR imaging characteristics and location of a trochlear cleft were determined. Imaging results were compared to arthroscopy when available. Patient age and gender were compared to 25 randomly selected control patients without trochlear clefts. RESULTS: A total of 25 (1.9%) individuals (11 females and 14 males; age range 19­45 years; mean age 28 years) were diagnosed with a trochlear cleft. The control group consisted of 11 females and 14 males; age range 19­83 years; mean age 46 years. Mean cleft length was 7 mm (range 6­12 mm); cleft location was consistently in the lower trochlear trough. No full-thickness cartilage defects were identified in the eight individuals in whom arthroscopic correlation was available. A grade 2 cartilage lesion was identified in a single individual; another progressed from grade 0 to a full-thickness trochlear lesion over an 8-month interval. Eight individuals were athletes. No significant difference in gender was noted between the two groups, however, the study group was significantly younger p<0.0001. CONCLUSIONS: A trochlear cleft is a rare finding in young active individuals. It most likely indicates an incomplete cartilage fissure which may rarely progress to a full-thickness defect.

Imaging of Noncontact Anterior Cruciate Ligament Injuries and Associated Bone Marrow Contusion Patterns.

Anterior cruciate ligament (ACL) tears are commonly associated with bone contusions. Bone contusions can lend important insight into increased risk for more subtle concurrent injuries based on common injury mechanisms and patterns, as higher energy trauma has been tied to patterns of specific bone contusions and concomitant injuries. Lateral compartment contusions are most common and occur in pivot shift injuries. Medial compartment contusions may represent a contrecoup mechanism after the initial lateral injuries. Patellotibial contusions require axial loading but are also typically seen in conjunction with lateral and medial compartment contusions. The differences in ACL injury mechanics and physiology as shown by imaging contusion patterns can help clinicians better identify and treat the concurrent associated injuries.

Review of Extensor Mechanism Injuries in the Dislocated Knee.

Knee dislocations, aka multiligamentous injuries, are uncommon but devastating injuries often following high-energy trauma. Tears of the major knee stabilizers are well documented; however, injuries of the knee extensor mechanism are less commonly reported. The extensor mechanism is comprised of the patella, patellar tendon, and quadriceps tendons. Magnetic resonance imaging (MRI) is the preferred imaging modality of internal derangements of the knee due to its excellent soft tissue contrast. In this article, we will discuss the normal imaging findings of the extensor mechanism and review abnormalities following knee dislocation.

Friction Syndromes of the Knee.

The knee is a complex joint with many fascial and ligamentous interactions. The movement in multiple planes makes the knee a prime site for friction syndromes, especially in active individuals. The most common friction syndrome is the iliotibial band friction syndrome. This occurs commonly in runners and cyclists and can be diagnosed clinically in a patient with lateral knee pain during activity. The anterior fat pads of the knee can also be the site of friction syndromes, most often in the Hoffa fat pad. Edema here can be located in the superolateral aspect of the fat pad when associated with patellar abnormalities, or diffusely when impingement is due to other causes. Edema of the quadriceps or prefemoral fat pad may also cause anterior knee pain and may be diagnosed with magnetic resonance imaging. The posteromedial friction syndrome and medial tibial crest syndrome are rare causes of medial knee pain highly active individuals.