An Anatomic Analysis of Mid-anterior and Anterolateral Approaches for Hip Arthrocentesis: A Male Cadaveric Study.

PURPOSE: To determine the accuracy and safety of non-image-guided modified mid-anterior and anterolateral approaches to the hip joint for arthrocentesis.

METHODS: Six pairs (n = 12) of human cadaveric hemipelvises underwent methylene blue hip injections through either a mid-anterior or an anterolateral approach. The distance from the mid-anterior approach to the lateral femoral cutaneous nerve (LFCN) was measured. Needle orientation was defined by a combination of 2 angles, calculated by the computer software analysis of digitized points. Distal Angle was defined as the angle between the lateral axis and an intermediate needle position, in the coronal plane, toward the distal axis. Anterior Angle was defined as the angle between the intermediate needle position of Distal Angle and the final position, toward the anterior axis.

RESULTS: Methylene blue was successfully injected into the joint capsule in all specimens. The mean distances from the needle to the LFCN for both the mid-anterior and anterolateral approaches were 19.3 ± 7.9 and 80.3 ± 28.3 mm, respectively. For the mid-anterior approach, Distal AngleM was a mean of 53.9° ± 14.9° and Anterior AngleM was a mean of 33.4° ± 15.6°. For the anterolateral approach, Distal AngleL was a mean of 14.5° ± 14.2° and Anterior AngleL was a mean of 4.5° ± 13.6°.

CONCLUSIONS: This study showed that mid-anterior and anterolateral approaches for non-image-guided hip injections or arthrocentesis can avoid the LFCN and be effectively performed in males, despite the exhibited variability in the quantitative descriptions of these techniques. The landmarks and measurements presented can be used as general guidelines for clinical studies regarding hip arthrocentesis and injections.

CLINICAL RELEVANCE: The high variability of the needle placement and trajectory of the mid-anterior and anterolateral approaches performed in this study showed that these techniques were not easily quantitatively defined. However, both of these approaches appeared to be safe and effective.