Retrospective evaluation of MRI findings in arthroscopically confirmed cases of hypermobile lateral meniscus.

OBJECTIVE: To identify preoperative MRI findings in patients with arthroscopically confirmed hypermobile lateral meniscus utilizing a standard MRI knee protocol, with comparison to normal control and lateral meniscal tear groups. SUBJECTS AND METHODS: All patients with arthroscopically confirmed hypermobile lateral meniscus diagnosed at our institution were retrospectively identified. The following structures were evaluated on preoperative knee MRIs: superior and inferior popliteomeniscal fascicles, lateral meniscus and meniscocapsular junction, popliteal hiatus, and soft tissue edema around the popliteal hiatus. The same MRI features were evaluated in the normal control and lateral meniscal tear groups. RESULTS: Study, normal control, and lateral meniscal tear patients (18 each) were included. In the study group, 94.4% had superior popliteomeniscal fascicle abnormality, 89.0% had inferior popliteomeniscal fascicle abnormality, and 72.2% had lateral meniscal abnormality. Incidence of these abnormalities was significantly higher than in the normal control group. Meniscal abnormalities in the study group all involved the posterior horn meniscocapsular junction, 12/13 of which had vertical signal abnormality at the junction and 1/13 with anterior subluxation of the entire posterior horn. Popliteus hiatus measurements were largest in the lateral meniscal tear group. CONCLUSION: In patients with hypermobile lateral meniscus, the combination of popliteomeniscal fascicle abnormality and vertical signal abnormality at the meniscocapsular junction was seen in the majority of patients. Popliteomeniscal fascicle signal abnormality without identifiable lateral meniscal injury was the next most common imaging appearance. Radiologists may provide valuable information by suggesting the diagnosis of hypermobile lateral meniscus in such cases.

Utility of preoperative MRI for assessing proximal fragment vascularity in scaphoid nonunion.

Aims: The benefit of MRI in the preoperative assessment of scaphoid proximal fragment vascularity remains controversial. The purpose of this study is to compare preoperative MRI findings to intraoperative bleeding of the proximal scaphoid. Methods: A retrospective review of 102 patients who underwent surgery for scaphoid nonunion between January 2000 and December 2020 at a single institution were identified. Inclusion criteria were: isolated scaphoid nonunion; preoperative MRI assessing the proximal fragment vascularity; and operative details of the vascularity of the proximal fragment with the tourniquet deflated. MRI results and intraoperative findings were dichotomized as either 'yes' or 'no' for the presence of vascularity. A four-fold contingency table was used to analyze the utility of preoperative MRI with 95% confidence intervals. Relative risk was calculated for subgroups to analyze the association between variables and MRI accuracy. Results: Preoperative MRI identified 55 proximal scaphoid fragments with ischaemia and 47 with vascularized proximal fragments. After the proximal fragment was prepared, the tourniquet was deflated and assessed for bleeding; 63 proximal fragments had no bleeding and 39 demonstrated bleeding. MRI was not reliable or accurate in the assessment of proximal fragment vascularity when compared with intraoperative assessment of bleeding. No patient or MRI factors were identified to have a statistical impact on MRI accuracy. Conclusion: Current preoperative MRI protocols and diagnostic criteria do not provide a high degree of correlation with observed intraoperative assessment of proximal fragment bleeding. While preoperative MRI may assist in surgical planning, intraoperative assessment remains the best means for assessing proximal fragment vascularity in scaphoid nonunion. Future efforts should focus on the development of objective measures of osseous blood flow that may be performed intraoperatively.

Outcomes in patients with clinically suspected pedal osteomyelitis based on bone marrow signal pattern on MRI.

Objective: confluent T1 hypointense marrow signal is widely accepted to represent osteomyelitis on MRI. Some authors have suggested that non-confluent bone marrow signal abnormality should be considered early osteomyelitis. The purpose of this study was to address this issue by comparing the rate of osteomyelitis and amputation based on T1 marrow signal characteristics. Materials and methods: a total of 112 patients who underwent MRI of the foot for the evaluation of possible osteomyelitis were included. Patients were assigned to confluent T1 hypointense, reticulated T1 hypointense, and normal bone marrow signal groups. Results: patients with confluent T1 hypointense signal on MRI had significantly higher rates of osteomyelitis and amputation at 2 and 14 months post-MRI than the reticulated T1 hypointense group ( p < 0.001 ). Six patients had normal T1 signal, 16.7 % of whom had osteomyelitis and underwent amputation by 2 months post-MRI. Of 61 patients with reticulated T1 hypointense signal, 19.7 % had a diagnosis of osteomyelitis at 2 months post-MRI and 30.8 % had a diagnosis of osteomyelitis at 14 months post-MRI; moreover, 14.8 % and 31.5 % underwent amputation by 2 and 14 months post-MRI, respectively. Of 45 patients with confluent T1 hypointense signal, 73.3 % of patients had osteomyelitis at 2 months post-MRI and 82.5 % had osteomyelitis at 14 months post-MRI. In this group, 66.7 % underwent amputation by 2 months post-MRI and 77.8 % underwent amputation by 14 months post-MRI. Conclusions: over half of the patients with suspected pedal osteomyelitis who had reticulated or normal T1 bone marrow signal on MRI healed with conservative measures. Therefore, we recommend terminology such as "osteitis", "reactive osteitis", or "nonspecific reactive change" to describe bone marrow edema-like signal and reticulated hazy T1 hypointense signal without associated confluent T1 hypointensity. Moreover, we recommend that the MRI diagnosis of osteomyelitis is reserved for confluent T1 hypointense bone signal in the area of concern.

Multimodality evaluation of transfascial muscle and other soft tissue herniations of the extremities.

This review illustrates the multimodality assessment of transfascial muscle and other soft tissue herniations of the extremities. Transfascial herniations of the extremities can develop from congenital or acquired disruptions of the deep fascia, resulting in herniation of the underlying muscle, nerve, or soft tissue tumor into the subcutaneous tissues. While most patients present with a painless subcutaneous nodule that may change in size with muscle activation, some may experience focal or diffuse extremity symptoms such as pain and paresthesias. Although the diagnosis may be clinically suspected, radiologic evaluation is useful for definitive diagnosis and characterization. Ultrasound is the preferred modality for initial workup through a focused and dynamic examination. Magnetic resonance imaging can be utilized for equivocal, complicated, and preoperative cases. Computed tomography is less useful in the evaluation of transfascial herniations in the extremities due to similarities in the attenuation between muscle and fascia, which can decrease the conspicuity of small defects.

Advantages of CT Versus MRI for Preoperative Assessment of Osteochondritis Dissecans of the Capitellum.

BACKGROUND: Magnetic resonance imaging (MRI) is considered to be the gold standard for imaging of osteochondritis dissecans (OCD). PURPOSE/HYPOTHESIS: The purpose was to determine the additional value of a preoperative computed tomography (CT) scan in adolescent patients with capitellar OCD of the elbow. Consistent with the fact that OCD is a lesion involving the subchondral bone, the hypothesis was that CT would be superior to MRI for imaging OCD of the capitellum. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 3. METHODS: All patients being treated surgically for an OCD of the capitellum between 2006 and 2016 at one institution were reviewed for preoperative imaging. A total of 28 patients met the inclusion criteria. Corresponding MRI and CT scans were compared retrospectively. Multiple parameters were recorded, with special emphasis on OCD lesion size, fragmentation, and tilt as well as joint surface integrity, loose bodies, and osteophytes. RESULTS: The OCD lesions were best seen on CT scans, whereas MRI T1-weighted images overestimated and T2-weighted images underestimated the size of defects. A subchondral fracture nonunion was found on CT scans in 18 patients, whereas this was seen on MRI T1-weighted images in only 2 patients (P < .001) and MRI T2-weighted images in 4 patients (P < .001). Fragmentation of the OCD fragment was found on CT scans in 17 patients but on MRI scans in only 9 patients (P = .05). Osteophytes as a sign of secondary degenerative changes were seen on CT scans in 24 patients and were seen on MRI scans in 15 patients (P = .02). Altogether, only 51 of 89 secondary changes including loose bodies, effects on the radial head and ulnohumeral joint, and osteophytes that were seen on CT scans were also seen on MRI scans (P = .002). CONCLUSION: OCD fragmentation and secondary changes were more often diagnosed on CT. These factors indicate OCD instability or advanced OCD stages, which are indications for surgery. In an adolescent who is considered at risk for OCD (baseball, gymnastics, weightlifting, tennis) and who has lateral elbow joint pain with axial or valgus load bearing, CT is our imaging modality of choice for diagnosing and staging OCD of the capitellum.

Traumatic rupture of the midportion of the interosseous membrane: a rare cause of acute lower leg pain in two soccer players kicked in the anterior shin.

The interosseous membrane (IOM) of the leg is a component of the tibiofibular syndesmosis that serves an important role in stabilization, as well as transferring forces to the fibula during weight-bearing. We present two separate cases of acute traumatic rupture of the midportion of the interosseous membrane in high school soccer players with blunt trauma to the anterior shin with MRI and ultrasound confirmation.

Medial patellofemoral ligament MRI abnormalities in the setting of MCL injuries: are they clinically relevant?

OBJECTIVE: To assess MRI abnormalities of the medial patellofemoral ligament (MPFL) in patients with clinically and MRI-proven superficial medial collateral ligament (sMCL) injuries and determine the clinical significance. MATERIALS AND METHODS: High-field strength knee MRI examinations were selected which demonstrated sMCL injuries. These cases were retrospectively reviewed for the presence, location, and severity of MPFL abnormality. The MPFL was divided into a more superior transverse component arising from a femoral attachment (tMPFL), and a broader more inferior oblique decussation component (odMPFL) arising from the anterior margin of the upper sMCL. Chart review was performed to determine the clinical relevance of any MPFL findings. RESULTS: One hundred patients with MCL injury were identified. These included 37 grade I sprains, 33 partial tears, 20 high-grade partial tears, and 10 full thickness tears. Abnormal edema was present at the femoral attachment of the tMPFL in 83%. The odMPFL was abnormal in 90%, most commonly involving the femoral third. No patients had imaging evidence of concurrent lateral patellar dislocation on the initial MRI study. No patients had documented patellofemoral instability at the time of original injury or upon follow-up. No patients required MPFL reconstruction. CONCLUSION: The MRI appearance of the MPFL is abnormal in the majority of patients with clinically and MRI-documented sMCL sprains and tears. These cases had no evidence of concurrent lateral patellar dislocation on the initial MRI and did not develop patellar instability symptoms.

Understanding the Implications of the Meniscal Ossicle: Patient Presentation, Treatment, and Outcomes.

The meniscal ossicle is observed in clinical practice, yet there currently is limited information on its potential clinical significance. The purpose of this study was to assess the clinical presentation, imaging findings, and clinical treatment and outcomes of a series of patients identified as having a meniscal ossicle. An institutional database was reviewed to identify knees with a meniscal ossicle. Clinical presentation, magnetic resonance imaging (MRI), treatment, and outcomes were analyzed. Radiographs were graded using Kellgren-Lawrence (KL) scores. MRIs were reviewed for the presence and location of meniscal ossicles and additional knee pathology. Knee arthroplasty rates were recorded with the remaining patients contacted to obtain final International Knee Documentation Committee (IKDC) and Tegner's scores. Failure was defined as conversion to arthroplasty or failing IKDC score (< 75.4). Forty-five meniscal ossicles in 45 patients (26 males and 19 females) with a mean age of 51 years (standard deviation [SD] = 19.0) were included. Pain was the most common presenting symptom (89%). Forty-two patients (93%) had an associated meniscus root tear on MRI. Eighteen percent of patients that did not have an ossicle on initial imaging subsequently developed an ossicle. Mean KL grades progressed significantly from baseline of 1.84 (SD = 1.0) to 2.55 (SD = 0.93 p < 0.01) on final follow-up. Thirty-nine percent of baseline radiographs showed KL grades of less than 2 compared with only 15% of follow-up radiographs (p = 0.04). Mean IKDC score obtained for patients ≤ 60 at an average follow-up of 3.1 years (SD = 3.2) was 65.2 (SD = 19.0). Eight out of 45 patients (18%) had progressed to total knee arthroplasty (TKA) by latest available follow-up. Sixty-two percent of patients met failure criteria at latest available follow-up. The meniscal ossicle is most commonly found in the posterior horn or root of the medial meniscus and is highly suggestive to be sequelae of a posterior root tear. Therefore, the presence of a meniscal ossicle should alert the orthopaedic surgeon to the high likelihood of the patient having a meniscus root tear. These patients have shown to have poor clinical outcomes and worsening arthritis.

Utility of the FABS MRI sequence in the evaluation of distal biceps pathology.

OBJECTIVE: The flexed elbow, abducted shoulder, forearm supinated (FABS) position has been described as a method of imaging the distal biceps tendon on its long axis. The purpose of this study is to evaluate whether obtaining additional MR imaging in the FABS position changes the radiologist's assessment of the distal biceps tendon compared with traditional sequences only. MATERIALS AND METHODS: Blinded review of 46 elbow MRIs when viewed without (-F) and with (+F) FABS sequences available was performed by two independent readers. The biceps tendon was graded in each case using a 0-3 scale, and a confidence level of 0-10 was assigned. -F and +F reads were compared. Reads were also compared with the surgical reference standard when available, 12 patients. RESULTS: Pooled intra rater reliability was 0.800 (0.714, 0.886) between the -F and +F groups. Pooled mean confidence was 7.163 (1.252) for the -F group and 8.370 (1.264) for the +F group (p < 0.001). Pooled diagnostic accuracy was 0.651 (0.420, 0.882) for the -F group and 0.615 (0.456, 0.875) for the +F group compared with the surgical reference standard. CONCLUSION: The FABS sequence changed the radiologist's impression of the distal biceps tendon in the minority of cases and did not significantly change diagnostic accuracy. We do not recommend its use in the majority of cases. In challenging cases of high-grade partial vs complete tendon tear, FABS may be helpful to identify subtle residual tendon fibers.

MRI appearance of jogger's foot.

OBJECTIVE: To characterize the MRI findings present in patients with clinically proven or suspected jogger's foot. MATERIALS AND METHODS: Ten years of medical charts in patients clinically suspected of having jogger's foot and who had MRI studies completed were identified utilizing a computer database search. Six study cases were identified. The MRI examinations of the study cases and an age- and gender-matched control group were reviewed in a blinded fashion by two musculoskeletal radiologists. Size and signal intensity of the medial plantar nerve were measured and characterized. The medial foot musculature was assessed for acute or chronic denervation changes. RESULTS: The medial plantar nerve was found to have moderately increased T2 signal compared with normal skeletal muscle in 3/6 study group cases and markedly increased T2 signal in the remaining 3/6 cases. In all control cases, the nerve was reported to have T2 signal equal or minimally higher than normal skeletal muscle. The mean total size of the medial plantar nerve was significantly larger in the study group when compared with that in the control group at all measured locations (p < 0.04). CONCLUSIONS: Abnormal thickness and T2 hyperintensity of the medial plantar nerve centered at the master knot of Henry are characteristic MRI findings in patients with jogger's foot when compared with control subjects. Muscular denervation changes may also be seen, most commonly in the flexor hallucis brevis muscle.

Iliopsoas Release in Hip Arthroscopy: Assessment of Muscle Atrophy.

Iliopsoas release is a common procedure for coxa saltans interna of the hip. The possible sequelae from this surgery have not been well studied. The purpose of this study was to determine postoperative atrophy and morphology of the cut tendon. This retrospective review included patients who underwent arthroscopic iliopsoas release and had magnetic resonance imaging of the ipsilateral hip before and after surgical intervention. Cross-sectional area measurements were obtained of the iliopsoas muscle at the level of the distal anterior inferior iliac spine as well as at the L5 vertebral pedicle in patients who had imaging that included the lower lumbar spine. Patient-reported outcomes included the modified Harris Hip Score (mHHS) and the Hip Outcome Score subscales for activities of daily living (HOS ADL) and sport (HOS Sport). A total of 44 patients met inclusion criteria for this study; 26 patients had additional advanced imaging that included the lumbar spine. The cross-sectional area of the iliopsoas at the level of the anterior inferior iliac spine decreased postoperatively by a mean of 191.4 mm2;, this difference was statistically significant (P<.0001). Mean area at the L5 pedicle was 628.9 mm2 on the released side and 1216.2 mm2 on the nonoperative side (P<.05). Mean Goutallier-Fuchs score of the released iliopsoas at the L5 pedicle was 1.3 (SD, 0.7). Mean mHHS, HOS ADL, and HOS Sport scores for patients at least 1 year postoperatively were 51, 56, and 42, respectively. [Orthopedics. 2020;43(3):e171-e176.].

Osteomeniscal Impact Edema (OMIE): Description of a Distinct MRI Finding in Displaced Flap Tears of the Medial Meniscus, with Comparison to Posterior Root Tears.

Bone marrow edema (BME) can be a late finding in osteoarthritis or a sign of subchondral insufficiency. The purpose of this study was to describe the magnetic resonance imaging (MRI) finding we refer to as "osteomeniscal impact edema" (OMIE), or reactive BME adjacent to a displaced meniscus flap tear. In addition, this edema pattern is compared with a control group of medial meniscus posterior root tears (MMPRT) with subchondral insufficiency edema. MRI records from 2000 to 2017 were retrospectively reviewed for studies that showed the presence of a medial meniscus displaced flap tear and an adjacent area of BME. The selected MRIs were matched to an equal number of MMPRT MRI studies. All MRI studies were assessed for cartilage surface grade using the modified Outerbridge classification system and for the extent of accompanying structural abnormalities using the whole-organ magnetic resonance imaging score. Descriptive statistics and hypothesis testing were utilized to compare the MRI findings between groups. Twenty-two flap tear (OMIE group) patients with a mean age of 57 (SD: 15) and 22 root tear (MMPRT) group patients with a mean age of 61 (SD: 10) were included. MRIs in the OMIE group showed a distinctive pattern of focal, peripheral edema adjacent to the meniscus flap tear, compared with more diffuse, central edema in the MMPRT group. Quantitatively, MRIs of the MMPRT group showed significantly worse mean femoral Outerbridge scores (3.72 vs. 2.68, p < 0.0001), more severe central (1.63 vs. 0.5, p = 0.0007) and posterior (0.31 vs. 0.0, p = 0.04) subchondral edema grades, and a higher incidence of tibial subchondral fractures (3 vs. 0, p = 0.036). Meniscus flap tears may present with a distinct MRI pattern of focal, adjacent, peripheral edema, which we refer to as OMIE. Patients with meniscus flap tears showed significantly less arthritic change, lower subchondral edema grades, and a lower incidence of insufficiency fractures and subchondral collapse compared with the diffuse overload edema pattern found with root tears. The Level of Evidence for this study is III.

Osteochondral lesions of the lateral trochlear ridge: a rare, subtle but important finding on advanced imaging in patients with elbow pain.

OBJECTIVE: To characterize the radiographic, CT, and MRI appearance of clinically and/or surgically proven osteochondral lesions of the lateral trochlear ridge. MATERIALS AND METHODS: Ten years of medical charts with elbow radiographic, CT, and MRI studies were retrospectively reviewed. Patients with pathology isolated to the lateral trochlear ridge were included. Studies were reviewed by two radiologists. Identifiable pathology on each type of study was noted and characterized. RESULTS: Ten elbow studies were included, all from males aged 15 to 58 years (mean 29 years). Five elbow radiographs were normal, one showed mixed lucency and sclerosis of the lateral trochlear ridge, and four demonstrated small osseous fragments adjacent to the ridge. In all cases, CT demonstrated focal lucency at the cortical surface of the lateral trochlear ridge; 8 contained small osseous fragments, axial plane maximum width ranged from 5 to11 mm, depth from 1 to 2 mm. Focal bone marrow edema in the subchondral lateral trochlear ridge was found in the 6 cases with MR images. Two demonstrated linear high signal underlying the in situ osseous fragment, faintly visible on MRI. In 9 cases, arthroscopy was performed within 3 months of imaging. The remaining patient was treated conservatively with casting. CONCLUSIONS: Osteochondral lesions of the lateral trochlear ridge are rare but important, as these patients go on to arthroscopy at a high rate. If an abnormality of the lateral trochlear ridge is seen or suspected, we recommend CT as the best imaging study to define these lesions.

MRI appearance of the anomalous volar radiotriquetral ligament in true Madelung deformity.

OBJECTIVE: To characterize the MRI appearance of the anomalous volar radiotriquetral ligament in cases of classic Madelung deformity. MATERIALS AND METHODS: With institutional review board approval, a search of the radiology information system was performed to identify cases of potential Madelung deformity using variations of the criteria "Madelung deformity." Cases of classic Madelung deformity were included based on the following criteria: dorsal subluxation of the ulnar head, volar tilt of the distal radius, increased radial inclination of greater than 25°, triangulation of the carpus, and presence of Vickers ligament defined as an anomalous volar radiolunate ligament. Patients with a history of wrist trauma or severe degenerative change distorting anatomy were excluded. The resulting cases were reviewed to characterize the anomalous radiotriquetral ligament. RESULTS: Eight cases of classic Madelung deformity in 6 patients were identified. All 8 cases were characterized by the presence of an anomalous radiotriquetral ligament, which was more conspicuous than Vickers ligament. None of the excluded pseudo-Madelung deformity cases displayed a Vickers ligament or radiotriquetral ligament. CONCLUSION: The radiotriquetral ligament is an anomalous ligament that is a constant and distinguishing finding in classic Madelung deformity in this study. Awareness of the radiotriquetral ligament and distinguishing it from Vickers ligament on imaging studies and at surgery may have clinical implications that need to be further investigated.

MR arthrogram of the postoperative glenoid labrum: normal postoperative appearance versus recurrent tears.

OBJECTIVE: The purpose of this study is to describe the MR arthrogram appearance of the postoperative glenoid labrum and to describe the features consistent with recurrent tear. MATERIALS AND METHODS: We identified 30 patients who had undergone glenoid labral repair, had a subsequent MR arthrogram of his or her shoulder, and went on to repeat shoulder arthroscopy. Each MR arthrogram was reviewed blindly, and the glenoid labrum was described as normal, irregular, or torn. Additional findings recorded included the presence or absence of a paralabral cyst and suture anchors in the glenoid. The operative report was also reviewed for each patient to determine the status of the labrum at arthroscopy. RESULTS: Following consensus review, 18/30 MRIs were felt to demonstrate recurrent glenoid labral tear, 11/30 showed an irregular labrum, and 1/30 was called normal. The radiology impression regarding the presence or absence of a recurrent glenoid labral tear agreed with the operative report in 24/30 (80%) cases, and was discrepant in six. This equals 83.3% sensitivity and 81.8% specificity of MR arthrogram in the diagnosis of recurrent labral tear in this study. A paralabral cyst was present in 3/30 (10%) cases, all three of which were torn. CONCLUSIONS: MR arthrogram findings of signal equal to gadolinium or fluid within or underlying the glenoid labrum and markedly diminutive or absent labrum were the most useful features to diagnose recurrent tear. Some signal underlying the labrum, which is confined to the anterosuperior quadrant, may be normal. The secondary finding of a paralabral cyst was also highly sensitive for recurrent tear.

High Rate of Missed Lateral Meniscus Posterior Root Tears on Preoperative Magnetic Resonance Imaging.

BACKGROUND: Lateral meniscus posterior root tears (LMPRTs), if left untreated, can cause devastating effects to the knee, with rapid articular cartilage degeneration and loss of the meniscus as a secondary stabilizer. Detection and surgical repair of these defects have been linked to favorable outcomes, but preoperative identification of LMPRTs continues to be challenging. PURPOSE: To determine the rate of LMPRTs diagnosed preoperatively on magnetic resonance imaging (MRI) in a consecutive series of arthroscopically confirmed LMPRTs. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective cohort of 45 consecutive patients with arthroscopically confirmed LMPRTs between 2010 and 2017 were included in this study. The preoperative MRI report for each patient was evaluated and compared with intraoperative findings. Each preoperative MRI study was then reviewed by 2 fellowship-trained musculoskeletal radiologists who worked in consensus. RESULTS: A total of 45 patients (32 males, 13 females) with arthroscopically confirmed LMPRTs and a mean age of 27 years (range, 14-54 years) were included in the study. Only 15 of 45 LMPRTs (33%) were initially diagnosed on preoperative MRI. Past or concurrent anterior cruciate ligament (ACL) reconstruction was present in 37 of 45 cases (82%). Upon retrospective review, 15 of the 30 missed LMPRTs were "clearly evident," 12 "subtly evident," and 3 "occult" (unavoidably missed). There were no significant differences in the rate of LMPRT diagnosis based on history of prior knee surgery, meniscus extrusion, or tearing of the meniscofemoral ligament. CONCLUSION: Despite improved identification of other meniscus tear patterns on MRI, a high percentage of LMPRTs were still missed. In the setting of previous ACL reconstruction, if the root cannot be confidently identified, the MRI interpretation should indicate that "the root is poorly visualized" to alert the surgeon to thoroughly evaluate this structure. The surgeon should maintain a high index of suspicion and carefully probe the posterior root of the lateral meniscus at the time of arthroscopy, especially in cases of ACL injury.

Stem Cells Combined With Platelet-rich Plasma Effectively Treat Corticosteroid-induced Osteonecrosis of the Hip: A Prospective Study.

BACKGROUND: Randomized trials have shown the benefits of injecting bone marrow-derived mesenchymal stem cells (BmMSCs) after standard hip decompression in patients with osteonecrosis of the femoral head. However, the combination of BmMSCs and platelet-rich plasma (PRP) injected into the femoral head after decompression has not been reported previously. This study reports the results in a preliminary series of patients with osteonecrosis of the femoral head treated with BmMSCs plus PRP. QUESTIONS/PURPOSES: (1) What is the survivorship free from reoperation, hip arthroplasty, and femoral head collapse in a preliminary series of patients with osteonecrosis of the femoral head treated with BmMSCs plus PRP? (2) Is there a change in the degree of femoral head involvement based on modified Kerboul angle? (3) What were the scores observed for pain and function at last followup? (4) Was there a difference in survivorship free from reoperation as a function of in vitro MSC count and viability? METHODS: Twenty-two consecutive patients (35 hips; 11 men and 11 women) with corticosteroid-induced osteonecrosis who met study inclusion criteria were enrolled; none declined participation, and none was lost to followup, although one patient (two hips) died within a year of the procedure for reasons unrelated to it, and five patients (seven hips) did not undergo MRI at the 1-year followup. All patients had precollapse osteonecrosis, rated either University of Pennsylvania Stage 1 (n = 4) or Stage 2 (n = 31 hips). Mean age and body mass index were 43 years and 31 kg/m, respectively. Patients underwent pre- and postoperative radiographs and MRI to assess femoral head involvement using the modified Kerboul angle. Absolute cell count and colony-forming unit (CFU) assays were used to assess MSC abundance and viability of the bone marrow obtained at the time of surgery. Patients were followed at regular intervals to assess clinical response to treatment with a mean followup of 3 years (range, 2-4 years). The change in femoral head involvement was assessed with the modified Kerboul angle; the Harris hip score was used to assess clinical outcome; and conversion to THA, reoperation, and survivorship free from femoral head collapse were analyzed with the Kaplan-Meier method on a per-hip basis. RESULTS: Survivorship free from THA, any procedure, and femoral head collapse was 84% (95% confidence interval [CI], 75%-93%), 67% (95% CI, 55%-79%), and 93% (95% CI, 76%-98%), respectively, at 3 years postoperatively; two patients (four hips) underwent a second decompression and MSC injection for persistent pain without signs of radiographic collapse. All patients with collapse underwent THA. The mean modified Kerboul angle improved from 205° ± 47° to 172° ± 48° postoperatively (mean change -30° ± 6°, p = 0.01). A greater proportion of patients who underwent an additional procedure had a modified Kerboul grade of 3 or 4 preoperatively (80% [four of five] versus 13% [four of 30 Grade 1 or 2; odds ratio, 26; 95% CI, 2-296; p = 0.005). Preoperatively the mean Harris hip score was 57 ± 12, which improved to 85 ± 15 (mean change 28 ± 3, p < 0.001) at most recent followup. Patients undergoing a reoperation or THA had a lower mean concentration of nucleated cells/mL (5.5 x 10 ± 2.8 x 10 cells/mL versus 2.3 x 10 ± 2.2 x 10 cells/mL, p = 0.02) and lower mean CFUs (13 ± 6 versus 19 ± 7, p = 0.04) compared with those who did not. CONCLUSIONS: Core hip decompression with injection of concentrated bone marrow plus PRP improved pain and function; > 90% of hips in this series were without collapse at a minimum of 2 years. In this preliminary study, successful results were seen when nucleated cell count was high and modified Kerboul grade was low. Further randomized studies are needed to determine this procedure's efficacy versus core decompression or nonoperative treatment alone. LEVEL OF EVIDENCE: Level II, therapeutic study.

Arthritis Progression on Serial MRIs Following Diagnosis of Medial Meniscal Posterior Horn Root Tear.

Medial meniscus posterior root tears (MMPRTs) are a significant source of pain and dysfunction. The purpose of this study was to evaluate changes in the medial compartment of the knee over time following the diagnosis of a MMPRT on MRI. A retrospective review of the institutional database was performed for patients with an initial MRI diagnosis of a MMPRT. Patients were included if they had a subsequent follow-up MRI on the same knee. Patients with surgical intervention, including debridement or repair, were excluded. MRIs were evaluated by two board-certified musculoskeletal radiologists. MMPRTs were defined using the LaPrade classification, and the medial compartment articular cartilage was graded using the modified Outerbridge classification. MRIs were reviewed for meniscus extrusion, subchondral bone edema, and insufficiency fractures. Patients were divided into two groups for the analysis to account for differences in MRI time intervals. Group 1 had a follow-up MRI within 12 months of initial imaging (subacute group) and Group 2 had a follow-up MRI greater than 12 months after initial imaging (chronic group). Forty-one knees and 82 MRIs were analyzed, including 20 knees/40 MRIs (13 females, 7 males) in the subacute group and 21 knees/42 MRIs (14 females, 7 males) in the chronic group. Subacute patients had a mean age of 59.5 ± 8.8 years and a mean interval of 4.8 ± 2.6 months between MRIs compared with 53.6 ± 11.0 years and 38.2 ± 20.8 months, respectively, for the chronic group. Meniscal extrusion, femoral modified Outerbridge grade, and tibial modified Outerbridge grade worsened between initial and final MRI in both groups (p < 0.05). In both groups, there were no significant differences between initial and final MRIs with regard to the LaPrade classification, insufficiency fracture, or subchondral cysts of the tibia. Progressive meniscus extrusion and medial compartment articular cartilage degeneration were seen in patients with MMPRTs within a year from diagnosis.