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Background: Arthroscopic partial meniscectomy (APM) is widely performed and remains an important therapeutic option for patients with a meniscal tear. However, it is debated whether or not APM accelerates the progression of osteoarthritis (OA) in the long term., Purpose/hypothesis: The purpose was to compare the progression of OA measured by the change in tibiofemoral joint space width (JSW)-a quantitative measure of OA radiographic severity-across 3 groups with a midterm follow-up: (1) patients undergoing APM; (2) those with a meniscal tear treated nonoperatively; and (3) those without a tear. We hypothesized that the reduction in JSW would be greatest in patients undergoing APM and least in those patients without a tear., Study Design: Cohort study; Level of evidence, 3., Methods: Using the Osteoarthritis Initiative cohort, a total of 144 patients were identified that underwent APM with at least 12 months of follow up and without previous knee surgery. Those with a meniscal tear who did not have APM (n = 144) and those without a tear (n = 144) were matched to patients who had APM by sex, age, Kellgren-Lawrence (KL) grade, and follow up time. Participants underwent magnetic resonance imaging at baseline. Knee radiographs to assess JSW were collected annually or biannually. The change in minimum medial compartment JSW was calculated using a validated automated method. A piecewise linear mixed effects model was constructed to examine the relationship between JSW decline over time and treatment group-adjusting for age, body mass index, smoking status, KL grade, and baseline JSW., Results: All groups had comparable baseline JSW-ranging from 4.33 mm to 4.38 mm. The APM group had a rate of JSW decline of -0.083 mm/mo in the first 12 months and -0.014 mm/mo between 12 and 72 months. The rate of JSW decline in the APM group was approximately 27 times greater in the first 12 months than that in the nonsurgical group (-0.003 mm/mo) and 5 times greater than that in the no tear group (-0.015 mm/mo); however, there was no significant difference between groups for 12 to 72 months (nonsurgical group: -0.009 mm/mo; no tear group: -0.010 mm/mo). The adjusted JSW in the APM group was 4.38 mm at baseline and decreased to 2.57 mm at 72 months; the JSW in the nonsurgical group declined from 4.31 mm to 3.73 mm, and in the no tear group it declined from 4.33 mm to 3.54 mm. There was a statistically significant difference in JSW change between baseline and 72 months for the APM group compared with the other groups ( P < .001), but not between the nonsurgical and no tear groups ( P = .12)., Conclusion: In the first postoperative year, APM results in a faster rate of joint space narrowing compared with knees undergoing nonsurgical management of meniscal tears. Thereafter, there are comparable rates of OA progression regardless of the chosen management. APM results in a persistent decrease in JSW over at least 72 months. An untreated meniscal tear does not contribute to radiographic progression-assessed by JSW-as compared with an intact meniscus.

Objective: To identify risk factors for radiographic signs of post-traumatic osteoarthritis (OA) 2-3 years after anterior cruciate ligament (ACL) reconstruction through multivariable analysis of minimum joint space width (mJSW) differences in a specially designed nested cohort., Methods: A nested cohort within the Multicenter Orthopaedic Outcomes Network (MOON) cohort included 262 patients (148 females, average age 20) injured in sport who underwent ACL reconstruction in a previously uninjured knee, were 35 or younger, and did not have ACL revision or contralateral knee surgery. mJSW on semi-flexed radiographs was measured in the medial compartment using a validated computerized method. A multivariable generalized linear model was constructed to assess mJSW difference between the ACL reconstructed and contralateral control knees while adjusting for potential confounding factors., Results: Unexpectedly, we found the mean mJSW was 0.35 mm wider in ACL reconstructed than in control knees (5.06 mm (95% CI 4.96-5.15 mm) vs 4.71 mm (95% CI 4.62-4.80 mm), P < 0.001). However, ACL reconstructed knees with meniscectomy had narrower mJSW compared to contralateral normal knees by 0.64 mm (95% C.I. 0.38-0.90 mm) (P < 0.001). Age (P < 0.001) and meniscus repair (P = 0.001) were also significantly associated with mJSW difference., Conclusion: Semi-flexed radiographs can detect differences in mJSW between ACL reconstructed and contralateral normal knees 2-3 years following ACL reconstruction, and the unexpected wider mJSW in ACL reconstructed knees may represent the earliest manifestation of post-traumatic osteoarthritis and warrants further study., (Copyright © 2015. Published by Elsevier Ltd.)

Cartilage injuries in the knee are common and can be a persistent source of pain or dysfunction. Many new surgical strategies have been developed to treat these lesions. It is important for the radiologist to have an understanding of these procedures and their appearance on magnetic resonance (MR) imaging. This article provides the radiologist with an overview of the surgical strategies for repairing cartilage lesions in the knee followed by a discussion of their postoperative appearance on MR imaging in normal and abnormal cases. Guidelines for adequate reporting of the MR imaging findings after cartilage repair in the knee are also included., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: To determine whether subarticular marrow changes deep to the posterior horn medial meniscal root anchor might predict subsequent medial meniscal root tear., Materials and Methods: Fifteen patients with MR-diagnosed posterior horn medial meniscal root (PHMMR) tear and a knee MRI antecedent to the tear were identified at three imaging centers over a 7-year period. The pre- and post-tear MR images were evaluated for marrow signal changes deep to the root anchor, meniscal root signal intensity, medial compartment articular cartilage thinning, and meniscal body extrusion. Images of 29 age- and gender-matched individuals with two MRIs of the same knee were reviewed as a control group., Results: MRI in 11 of 15 (73%) cases with subsequent PHMMR tear demonstrated linear subcortical marrow edema deep to the meniscal root anchor on the antecedent MRI compared to only 1 of 29 (3%) non-tear controls (p < 0.0001). The abnormal signal resolved on post-tear MRI in all but two patients. Cyst-like changes deep to the PHMMR were present on initial MRI in three of 15 (23%) cases and three of 29 (10%) controls, persisting in all but one case on follow-up imaging. The PHMMR was gray on the initial MRI in seven of 15 (47%) of cases that developed tears compared to four of 29 (14%) controls (p < 0.0001). There was medial meniscal extrusion (MME) prior to tear in two of 15 (13%) patients and in ten of 15 (67%) patients after PHMMR failure. In the control group, MME was present in one (3%) and three (10%) of 29 subjects on the initial and follow-up MRIs, respectively. Articular cartilage loss was noted in two of 15 (15%) cases before tear and nine of 15 (69%) on follow-up imaging, as compared to one (3%) and four (14%) of 29 subjects in the control group., Conclusions: Subcortical marrow edema deep to the PHMMR may result from abnormal stresses and thus be a harbinger of meniscal root failure. This hypothesis is supported by resolution of these marrow signal changes after root tear. Following tear, extrusion of the meniscal body results in increased stress on the medial weight-bearing surfaces often leading to articular cartilage loss; we observed this sequence in six of our 15 patients with PHMMR tears.

Background: Septic arthritis is a rare but potentially devastating complication of anterior cruciate ligament (ACL) reconstruction surgery. Several studies, including one by this group, have reported short- and medium-term outcomes, but to our knowledge there are no long-term follow-up studies., Hypothesis: Postoperative septic arthritis after ACL reconstruction surgery will lead to diminished long-term outcomes compared with surgery without infectious complications, likely related to the development of arthritis., Study Design: Case series; Level of evidence, 4., Methods: Four of 831 consecutive patients undergoing arthroscopically guided ACL reconstruction surgeries performed by 1 surgeon were previously reported on by this group at an average follow-up of 36 months. These same patients were contacted and reevaluated. Each patient underwent a physical examination, functional testing, and subjective evaluations with the SF-36, Lysholm, International Knee Documentation Committee (IKDC), and Tegner activity scale scores. Plain film radiographs and magnetic resonance imaging (MRI) scans were analyzed by 2 musculoskeletal radiologists., Results: Average follow-up time for this study was 17.9 years, and average age was 44.3 years. No other injuries or surgeries had occurred from the time of the previous study. Each patient had a decline in SF-36, Lysholm, and IKDC score, and the average Tegner score was unchanged. Average vertical hop test performance and Biodex dynamometry were both improved. The average side-to-side displacement measured via the KT-1000 arthrometer was increased. Radiographic and MRI studies revealed progression of arthritis in all patients and ACL graft rupture in 1 patient., Conclusion: Patients who develop septic arthritis as a complication of ACL reconstruction surgery have diminished long-term subjective, functional, and radiographic outcomes compared with historical reports of uncomplicated cases, likely related to pain from advanced arthritis. As compared with their own earlier follow-up, these patients had declines in pain-related subjective measures but remained stable or improved in both functional testing and activity-related subjective scales.

Objective: The purpose of this study was to evaluate the diagnostic performance of sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) 3D fast spin-echo acquisition relative to conventional 2D fast spin-echo acquisition in the 3-T MRI evaluation of the menisci and ligaments of the knee., Materials and Methods: Images from all MRI knee examinations performed with a single 3-T system from September 2008 to January 2009 were reviewed. Seventy-one examinations of patients who subsequently underwent knee arthroscopy and an additional 29 examinations of patients who did not undergo surgery were selected for a total of 100 examinations. All imaging was performed with multiplanar conventional 2D and SPACE 3D fast spin-echo acquisitions. Six musculoskeletal radiologists independently reviewed the images. Area under the receiver operating characteristic (ROC) curve was calculated for the menisci and anterior cruciate ligament with arthroscopy as the reference standard. Disagreement between the two acquisitions was calculated for the posterior cruciate ligament and medial and lateral collateral ligaments. The Wilcoxon signed rank test was used to compare each reader's confidence scores for the two techniques., Results: For the medial meniscus, the average area under the ROC curve was statistically significantly larger (p = 0.01) with the conventional 2D (0.931) than with the SPACE 3D (0.893) technique. Average confidence in diagnosing medial meniscal tears also was statistically significantly greater with the 2D than with the 3D technique (p = 0.001). No statistically significant differences were found for the lateral meniscus or anterior cruciate ligament. The rate of discordance between findings with the 2D and 3D techniques was low for the posterior cruciate ligament and medial and lateral collateral ligaments (range, 4.2-5.7%)., Conclusion: In evaluation of menisci with 3-T MRI, readers performed better with conventional 2D acquisition than with SPACE 3D acquisition. In evaluation of ligaments, the readers had similar performance with the two acquisition methods.

Background: There are currently several approaches being pursued to treat focal defects of articular cartilage, each having specific advantages or challenges. A single-stage procedure that uses autologous cartilage fragments, Cartilage Autograft Implantation System (CAIS), is being evaluated in patients and may offer a clinically effective option., Purpose: To establish the safety of CAIS and to test whether CAIS improves quality of life by using standardized outcomes assessment tools., Study Design: Randomized controlled trial; Level of evidence, 2., Methods: Patients (n = 29) were randomized (1:2) with the intent to treat with either a control (microfracture [MFX]) or an experimental (CAIS) procedure. Patients were followed at predetermined time points for 2 years using several standardized outcomes assessment tools (SF-36, International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS]). Magnetic resonance imaging was performed at baseline, 3 weeks, and 6, 12, and 24 months., Results: Lesion size and International Cartilage Repair Society (ICRS) grade were similar in both groups. General outcome measures (eg, physical component score of the SF-36) indicated an overall improvement in both groups, and no differences in the number of adverse effects were noted in comparisons between the CAIS and MFX groups. The IKDC score of the CAIS group was significantly higher (73.9 ± 14.72 at 12 months and 82.95 ± 14.88 at 24 months) compared with the MFX group (57.78 ± 18.31 at 12 months and 59.5 ± 13.44 at 24 months). Select subdomains (4/5) in the KOOS instrument were significantly different at 12 and 18 months, and all subdomains (Symptoms and Stiffness, Pain, Activities of Daily Living, Sports and Recreation, Knee-related Quality of Life) were significantly increased at 24 months in CAIS with scores of 88.47 ± 11.68, 90.64 ± 7.87, 97.29 ± 3.8, 78.16 ± 22.06, and 69 ± 23.15 compared with 75 ± 9.31, 78.94 ± 13.73, 89.46 ± 8.13, 51.67 ± 26.01, and 37.15 ± 21.67 in the MFX group. These significant improvements were maintained at 24 months in both IKDC and KOOS. Qualitative analysis of the imaging data did not note differences between the 2 groups in fill of the graft bed, tissue integration, or presence of subchondral cysts. Patients treated with MFX had a significantly higher incidence of intralesional osteophyte formation (54% and 70% of total number of lesions treated) at 6 and 12 months when compared with CAIS (8% and 25% of total number of lesions treated)., Conclusion: The first clinical experience in using CAIS for treating patients with focal chondral defects indicates that it is a safe, feasible, and effective method that may improve long-term clinical outcomes.

Cartilage abnormalities in the knee and ankle are a common source of pain and are often difficult to diagnose clinically or radiographically. MR imaging is a valuable tool for diagnosing and characterizing cartilage lesions of both the knee and ankle. An understanding of the appearance of cartilage, and an understanding of how and when to report cartilage injury in the knee and ankle based on current grading systems allows the radiologist to provide the most helpful reports to referring clinicians. This article presents the range of cartilage pathologies in the knee and ankle and provides clinically relevant guidelines., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Lesions of the articular cartilage now are recognized as a common, often treatable source of joint disability. Magnetic resonance imaging (MRI) of articular cartilage is a sensitive, noninvasive method for the detection of focal articular cartilage lesions. Advancement in imaging technology now allows for high spatial resolution acquisitions that are able to identify most cartilage lesions, and these acquisitions can be incorporated into everyday clinical imaging protocols. Thus, screening for cartilage abnormalities can be accomplished, along with routine evaluation for ligament and meniscal abnormalities. Familiarity with the appearances of normal cartilage and the full spectrum of cartilage lesions will aid in specific diagnoses. Grading and sizing of cartilage lesions and any underlying bony abnormalities on MRI can help the surgeon in treatment planning; however, some significant cartilage lesions can be difficult to identify and grade by MRI.

There is now over 10 years experience with autologous chondrocyte implantation (ACI) for the management of full-thickness chondral injuries in the knee. This article briefly reviews the surgical procedure, the time lines of graft maturation, and patient rehabilitation in the context of postoperative magnetic resonance imaging (MRI) assessment. The normal and abnormal appearances of ACI repair cartilage on MR images are described, with an emphasis on the MR appearances of the complications that may occur after this procedure, and the usefulness of MR imaging for the surgeon.