Anatomy of the lateral circumflex femoral artery: Does the direct anterior approach to the hip jeopardize vascularization of the proximal femur?

BACKGROUND: Blood supply of the proximal metaphysis of the femur comes mainly from the lateral circumflex femoral artery (LCFA). Essentially, the anterior approach has gained popularity in hip surgery but routinely requires the ligation of the ascending branch of the LCFA. Until now, there is no study analysing the effect of previous hip surgery on the vascularization of the proximal femur. Notably, it might, however, have consequences on osteointegration of uncemented prosthesis as well as in the management of early complications. Therefore we conducted a retrospective study to address the following questions: (1) Is the blood supply of the trochanteric region impaired by previous hip surgery, (2) does the anterior approach alter it more than other ones? HYPOTHESIS: We hypothesised that the surgical approach to the hip influences blood supply of the proximal femur, as visualised by retrospective analysis of femoral digital subtraction arteriograms (FDSA). PATIENTS AND METHODS: A retrospective review of 1280 FDSA, performed for vascular indications with a standard frame rate, between 07/2014 and 06/2016 in a single institution. Qualitatively sufficient FDSA were divided into 4 groups according to the history of previous hip surgery: hip replacement through an anterior approach (n=10) or through a lateral approach (n=31), cephalomedullary nailing for fractures of the proximal femur (n=5), and a control group of 50 continuous patients without previous hip surgery. The number of frames was counted between contrast injection into the femoral bifurcation and filling of the ipsilateral vessels of the greater trochanter to measure a potential delay/impairment of its arterial perfusion. Anatomic variations of the LCFA were also recorded. RESULTS: The number of frames between contrast injection and visualisation of the blood supply of the greater trochanter was 3.6±0.9 (mean±SD) in the control group (p<0.001 vs. all other groups). In patients with a hip replacement, the delay was 7.0±1.9 frames for the anterior approach and 5.2±1.1 frames for the lateral approach, respectively. In patients after cephalomedullary nailing, a delay of 4.8±1.5 frames was measured. The delay in the anterior approach group was significantly longer (p<0.001) compared to all other investigated groups. The ascending branch of the LCFA could not be detected after the anterior approach. As after lateral approach or as in the control group, the transverse branch was detectable in approximately 2/3 of the patients. DISCUSSION: Arterial perfusion of the greater trochanter is impaired after hip surgery, particularly after an anterior approach. The clinical relevance of these findings still needs to be investigated. It might, however, explain some early aseptic failures of uncemented stems. Moreover, it should be considered in early revision surgery, because combining different approaches might critically impair femoral blood supply. LEVEL OF EVIDENCE: III, retrospective case control study.

MR imaging of pubic symphysis after uncomplicated vaginal delivery and planned caesarean delivery in the first postpartum week.

PURPOSE: To compare changes in the pubic symphysis between women with vaginal delivery and women with caesarean sections within the first postpartum week. MATERIALS AND METHODS: After institutional review board approval 30 healthy women were prospectively examined with MRI (transverse STIR-sequence) three days after delivery. 17 women with vaginal delivery (mean age 33.2 ±â€¯4 years) and 13 with caesarean delivery (35.2 ±â€¯5.6 years) were compared by two musculoskeletal radiologists. Bone marrow edema (location and extent), fluid in the joint gap, joint space width and stress fractures were assessed. RESULTS: Prevalence of bone marrow edema was high and not different between groups (13/17 (76.5%) vaginal deliveries) and 10/13 (76.9% caesarean deliveries) for reader 1 (p = 0.992) and 14/17 (82.4%) and 10/13 (76.9%) for reader 2 (p = 0.762). Size of bone marrow edema was not statistically significantly different for both readers (results reader 1: right side 2.5 ±â€¯3.3 mm vs. 6.3 ±â€¯7.3 mm, p = 0.300; left side 3.4 ±â€¯4.1 mm vs. 4.1 ±â€¯4.6 mm, p = 0.837). Fluid in the joint was seen in 4/17 (23.5%) vs. 2/13 (15.4%) (p = 0.580) for reader 1 (similar for reader 2). Joint space width did not differ between groups (2.6 ±â€¯0.7 mm vs. 3.1 ±â€¯1.2 mm, p = 0.198). Pubic symphysis diastasis (joint space width > 10 mm) was not observed. Interreader agreement for these parameters was substantial to almost perfect (0.671-0.984, kappa values/intraclass correlation). Reader 1 found no stress fractures, while reader 2 suspected 1 stress fracture on a right pubic bone in a woman after caesarean delivery. CONCLUSIONS: Pubic bone marrow edema is present in 3 of 4 women in the first postpartum week unrelated to the delivery mode.