The Use of Preoperative Dynamic Ultrasound to Predict Ulnar Nerve Stability Following In Situ Decompression for Cubital Tunnel Syndrome.

PURPOSE: To assess the use of preoperative, dynamic ultrasound to predict ulnar nerve instability following in situ decompression for cubital tunnel syndrome. METHODS: Prior to undergoing in situ decompression, 43 consecutive patients underwent dynamic ultrasound to assess the stability of the ulnar nerve during elbow flexion. The dynamic ultrasound findings were compared with the intraoperative assessment of nerve stability following in situ decompression. RESULTS: The preoperative dynamic ultrasound agreed with intraoperative findings in 38 of 43 patients (88%). Physical examination of ulnar nerve stability agreed with the intraoperative findings in 5 of 43 patients (12%). For the 5 of 43 cases in which the dynamic ultrasound did not correlate with the degree of ulnar nerve stability after in situ decompression, dynamic ultrasound overestimated the degree of ulnar nerve stability in 4 cases. CONCLUSIONS: Preoperative dynamic ultrasound can be used to accurately predict the degree of ulnar nerve instability following in situ decompression. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.

Magnetic resonance imaging after endoscopic carpal tunnel release.

PURPOSE: To determine with magnetic resonance imaging (MRI) the morphologic changes in the carpal tunnel and median nerve 3 months after endoscopic carpal tunnel release (ECTR). METHODS: We enrolled patients who had complete resolution of numbness and pain by 6 weeks after ECTR. Patients who met these inclusion criteria received an MRI at 3 months after surgery. Images were analyzed to determine whether median nerve morphology changes and discrete gap or separation of the flexor retinaculum could be appreciated on MRI. RESULTS: There were 17 patients screened and 15 met the inclusion criteria. Three-month MRI in all patients demonstrated changes in the flexor retinaculum over the median nerve. In all 15 patients, a distinct gap or separation in the fibers of the flexor retinaculum overlying the median nerve could not be appreciated. Median nerve width-to-height ratios at the level of the pisiform and at the hook of the hamate were 2.4 and 2.1, respectively. Median nerve cross-sectional area was 14.1 at the pisiform and 13.3 at the hook of the hamate. CONCLUSIONS: MRI of patients 3 months after successful ECTR does not demonstrate a discrete gap or separation in the flexor retinaculum overlying the median nerve but may be useful for evaluating median nerve morphology. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.

Median Nerve and Carpal Tunnel Morphology Before and After Endoscopic Carpal Tunnel Release: A 6-Year Follow-up Study.

BACKGROUND: Our purpose was to describe structural and morphological features of the median nerve and carpal tunnel on magnetic resonance imaging (MRI) studies obtained before, immediately after, 6 weeks after, and 6 years after endoscopic carpal tunnel release (ECTR). METHODS: In this prospective cohort study, 9 patients with a diagnosis of carpal tunnel syndrome (CTS) underwent ECTR. Standardized MRI studies were obtained before ECTR, immediately after ECTR, and 6 weeks and 6 years after surgery. Structural and morphological features of the median nerve and carpal tunnel were measured and assessed for each study with comparisons made between each time point. RESULTS: All 9 patients had complete symptom resolution postoperatively. On the immediate postoperative MRI, there was a discrete gap in the transverse carpal ligament in all patients. There was retinacular regrowth noted at 6 weeks in all cases. The median nerve cross-sectional area and the anterior-posterior dimension of the carpal tunnel at the level of the hamate increased immediately after surgery and these changes were maintained at 6 years. CONCLUSIONS: We defined structural and morphological changes on MRI for the median nerve and carpal tunnel in patients with continued symptom resolution 6 years after ECTR. Changes in median nerve and carpal tunnel morphology that occur immediately after surgery remain unchanged at mid-term follow-up in asymptomatic patients. Established imaging criteria for CTS may not apply to postoperative patients. Magnetic resonance imaging appears to be of limited clinical utility in the workup of persistent or recurrent CTS.

Trauma-Induced Resolution of Solitary Osteochondroma of the Distal Femur.

Osteochondromas are benign lesions manifested as bony protrusions capped by cartilage. The exact cause of these growths is not known, and there is no treatment other than surgical excision if the lesion becomes symptomatic. Spontaneous resolution is an uncommon phenomenon that is not completely understood. A 12-year-old girl presented with a mass behind the left knee diagnosed as an osteochondroma. She was followed with serial radiographs because the lesion was minimally symptomatic. At 2.5 years after presentation, the patient reported feeling a "pop" with knee hyperflexion, and radiographic follow-up confirmed a decrease in the size of the growth. The protrusion continued to decrease in size until it was no longer detectable with radiographs, physical examination, and advanced imaging. Spontaneously resolving osteochondromas have been previously documented, but the literature is limited. There were just over 20 cases reported as of the writing of this article, and only 1 other case includes postresolution magnetic resonance imaging. This report of localized trauma inducing spontaneous resolution provides additional evidence and insight supporting previous theories on spontaneous resolution of osteochondromas, which may assist in counseling patients and their families regarding expected natural history. [Orthopedics.2016; 39(5):e1001-e1004.].

Pitfalls of wrist MR imaging.

The radiologist serves as an indispensable consultant for those patients with wrist pain, by determining the causes of the pain and severity of the injury, helping to determine treatment options, and providing preoperative guidance for surgery, if planned. This article reviews normal anatomic variants and potential danger areas encountered by the radiologist when interpreting magnetic resonance imaging of the wrist.

MR imaging of knee instability.

The primary stabilizers of the knee can be functionally compartmentalized into the cruciate ligaments, the medial and posteromedial stabilizers, and the lateral and posterolateral stabilizers. This complex anatomy provides global knee stability. This article familiarizes the reader with the normal MR imaging appearance of these structures, and the changes following injury. The posteromedial and posterolateral corners are emphasized because recent research has improved the understanding of their importance, and their repair and reconstruction are becoming more common. Accurate identification of injury is important to ensuring optimal patient outcome.