Radiographic and surgical considerations in arthritis surgery of the hand.

Indications for hand surgeries include unremitting joint pain, deformity and stiffness, often secondary to arthritis. Several surgical options are available, including arthrodesis (fusion) and joint arthroplasty. Classically arthrodesis is performed in situations with poor bone stock and supporting soft tissues. Arthroplasty is reserved for patients and joints in which preservation of function is important and bone stock and soft tissue support are adequate. In this article we will review various techniques for arthrodesis and arthroplasty, their post-surgical imaging appearance, including key findings important to surgeons, and the findings that indicate post-surgical complications. Radiographs are the mainstay for postoperative evaluation and will be the focus of the imaging portions of this review. Advanced imaging modalities will be reviewed when applicable.

Acute non-contact anterior cruciate ligament tears are associated with relatively increased vastus medialis to semimembranosus cross-sectional area ratio: a case-control retrospective MR study.

OBJECTIVE: Hamstring muscle deficiency is increasingly recognized as a risk factor for anterior cruciate ligament (ACL) tears. The purpose of this study is to evaluate the vastus medialis to semimembranosus cross-sectional area (VM:SM CSA) ratio on magnetic resonance imaging (MRI) in patients with ACL tears compared to controls. MATERIALS AND METHODS: One hundred knee MRIs of acute ACL tear patients and 100 age-, sex-, and side-matched controls were included. Mechanism of injury, contact versus non-contact, was determined for each ACL tear subject. The VM:SM CSA was measured on individual axial slices with a novel method using image-processing software. One reader measured all 200 knees and the second reader measured 50 knees at random to assess inter-reader variability. The intraclass correlation coefficient (ICC) was calculated to evaluate for correlation between readers. T-tests were performed to evaluate for differences in VM:SM CSA ratios between the ACL tear group and control group. RESULTS: The ICC for agreement between the two readers was 0.991 (95% confidence interval 0.984-0.995). Acute ACL tear patients have an increased VM:SM CSA ratio compared to controls (1.44 vs. 1.28; p = 0.005). Non-contact acute ACL tear patients have an increased VM:SM CSA ratio compared to controls (1.48 vs. 1.20; p = 0.003), whereas contact acute ACL tear patients do not (1.23 vs. 1.26; p = 0.762). CONCLUSION: Acute non-contact ACL tears are associated with increased VM:SM CSA ratios, which may imply a relative deficiency in hamstring strength. This study also demonstrates a novel method of measuring the relative CSA of muscles on MRI.

Tibial tunnel and pretibial cysts following ACL graft reconstruction: MR imaging diagnosis.

Tunnel cyst formation is a rare complication after anterior cruciate ligament reconstruction, usually occurring 1-5 years post-operatively, which may occasionally be symptomatic. There are multiple proposed theories regarding the etiology of tunnel cysts. Theories include necrosis, foreign-body reaction, lack of complete graft osteo-integration, and intravasation of articular fluid. It is important to know if the tunnel cysts are communicating or not communicating with the joint, as surgical management may be different. Imaging characteristics on magnetic resonance images (MRI) include tibial tunnel widening, multilocular or unilocular cyst formation in the graft or tibial tunnel, with possible extension into the pretibial space, intercondylar notch, and/or popliteal fossa. The MR imaging differential diagnosis of tibial tunnel cysts includes infection, foreign-body granuloma, or tibial screw extrusion. Importantly, to the best of our knowledge, graft failure or instability has not been reported in association with tibial tunnel cysts.

MRI of placenta accreta: a new imaging perspective.

OBJECTIVE: The goal of this study was to identify new MR criteria and review established MR criteria for the diagnosis of placenta accreta. MR images of all patients presenting to our department for evaluation of placenta accreta over the previous 5 years were reviewed and findings were correlated with surgical pathology. CONCLUSION: We found the most sensitive MR criteria for the diagnosis of invasive placentation to be abnormal placental vascularity in addition to the previously described intraplacental T2 dark bands.

Internal impingement syndromes.

Internal causes of impingement are secondary to rotator cuff and capsular dysfunction and are categorized by the location of the impingement and the underlying pathophysiological or mechanical cause of the impingement. These include posterosuperior impingement, anterosuperior impingement, anterior impingement, and entrapment of the long head of the biceps tendon. The objective of this article is to review magnetic resonance imaging findings of each of the 4 types of internal impingement syndromes and discuss the pathophysiology behind the impingement.