Cruciate ligament avulsion fractures.

PURPOSE: The objective of this study was to assess the variability of cruciate avulsion fractures. TYPE OF STUDY: Retrospective observational study. METHODS: Standardized radiographs and computed tomography (CT) examinations were performed in 40 patients (31 male, 9 female; age range, 10 to 77 years) with cruciate avulsion fractures. RESULTS: The average age of patients with anterior cruciate ligament (ACL) avulsion fractures was 21.5 years and that of patients with posterior cruciate ligament (PCL) avulsion fractures was 42.9 years. Two basic patterns of avulsion fracture emerged. ACL fractures were either partial (62%) (with avulsion of anteromedial bundle) or extended (38%) and were comminuted in 25%. PCL fractures were either complete (47%) or extended (53%) and were comminuted in 50%. CT helped delineate fracture margins, comminution and extent. CONCLUSIONS: Although there is considerable variability in fracture type, 2 basic patterns of ACL and PCL avulsion fractures exist. CT helps delineate these features as a prelude to surgical fixation. LEVEL OF EVIDENCE: Level III.

Immunohistochemical characterization of cells in adult human patellar tendons.

Cells in tendons are conventionally identified as elongated tenocytes and ovoid tenoblasts, but specific markers for these cells are not available. The roles and interplay of these cells in tendon growth, remodeling, and healing are not well established. Therefore, we proposed to characterize these cells with respect to cell turnover, extracellular matrix metabolism, and expression of growth factors. Here we examined 14 healthy human patellar tendon samples for the expression of various proteins in tenocytes and tenoblasts, which were identified as elongated tendon cells and ovoid tendon cells, respectively. Matrix metalloproteinase 1 (MMP1), procollagen type I (procol I), heat shock protein 47 (hsp47), bone morphogenetic protein 12 (BMP12), 13 (BMP13), and transforming growth factor beta1 (TGFbeta1) were detected by immunohistochemistry (IHC). An image analysis of the IHC staining for proliferation cell nuclear antigen (PCNA) and apoptotic cells was performed to determine the proliferation index and the apoptosis index in elongated and ovoid tendon cells. The ovoid tendon cells expressed higher levels of procol I, hsp47, MMP1, BMP12, BMP13, and TGFbeta1 than the elongated tendon cells. Both the proliferation index and the apoptosis index of ovoid tendon cells were higher than those of the elongated tendon cells. The results suggested that ovoid tendon cells, conventionally recognized as tenoblasts, were more active in matrix remodeling. The expression of BMP 12, BMP13 and TGFbeta1 might be associated with the different cellular activities of tenoblasts and tenocytes.

Anterior shoulder dislocation: quantification of glenoid bone loss with CT.

OBJECTIVE: In recurrent anterior shoulder dislocation, glenoid bone loss may predispose the patient to further dislocation and failure of a Bankart repair. This study investigates the quantification of glenoid bone loss in anterior shoulder dislocation using CT. SUBJECTS AND METHODS: CT examinations were performed on 40 patients (average age, 31 years; range, 13-82 years), comprising 46 shoulders with anterior dislocation and 34 contralateral normal shoulders. Twenty shoulders in 10 healthy subjects were also examined. Both shoulders were examined simultaneously. Image reconstruction included oblique sagittal reformatted images en face to the glenoid fossa. Seven aspects of glenoid fossa shape and size were measured, including the cross-sectional area, maximum width, maximum height, and flattening of the anterior glenoid curvature. RESULTS: Variable flattening of the anterior glenoid curvature was a feature in 42 (91%) of 46 dislocated shoulders although it was seen in only two (4%) of 54 normal shoulders. Anterior glenoid flattening increased exponentially with an increasing number of dislocations. Anterior glenoid flattening, decreased maximum glenoid width, and decreased maximum width-to-length ratio were the most useful measures of bone loss. Maximum glenoid width was smaller than on the contralateral side in 79% of patients with unilateral dislocation by an average of 3.0 mm (range, 0.1-10 mm) or 10.8% (range, 0.4-32%). Glenoid cross-sectional area was a less useful measure of glenoid bone loss. CONCLUSION: Flattening of the anterior glenoid curvature is shown in most patients with anterior dislocation. In unilateral dislocation, a comparison of maximum glenoid width with that on the contralateral side was the best discriminator of moderate to severe glenoid bone loss.