Lower extremity venous malformations may put patients at risk for intra-articular subtype

Patients with the Bockenheimer subtype of diffuse venous malformation were at significant risk for the more clinically challenging intra-articular venous malformations, according to a study.

“Venous malformation (VM) is the most common vascular anomaly in the lower extremity,” Krystal M. Jones, MD, of the dermatology program at Boston Children’s Hospital and Harvard Medical School, and colleagues wrote. They suggested that VMs in this part of the body can be deep and clinically challenging and, as a result, cause more joint dysfunction than VMs in other places. “Early identification of [intra-articular (IA)]-VM is critical because of the risk for asymptomatic joint destruction.”

They noted that these anomalies may be classified as focal, multifocal or diffuse types. While it is understood IA-VMs found in the knee can predict morbidity, there is uncertainty surrounding potential associations between lower extremity VM and IA-VM.

In the current retrospective cohort study, Jones and colleagues classified 156 patients with lower extremity, nonsyndromic VMs by type to determine which, if any, carried associations with IA-VM. Focal VMs comprised 46% of the cohort, while 54% were diffuse. Of the diffuse anomalies, 31% were Bockenheimer subtype, while 69% were localized. The group observed IA-VM in 62% of patients.

IA-VM was observed in 73% of diffuse type anomalies, while only 49% of focal types demonstrated IA-VM. Further data showed that 100% of diffuse Bockenheimer type VMs had IA-VM. Consequently, this subtype carried the highest risk for this outcome (RR = 1.83; 95% CI, 1.56-2.14).

A significant association was observed for pure VM as a factor in elevated IA-VM risk (RR = 2.34; 95% CI, 1.42-3.89). In addition, the risk for IA-VM was significantly elevated among patients with diffuse type VMs (RR = 1.48; 95% CI, 1.13-1.94).

The researchers noted that the retrospective, single-center nature of the study may limit the applicability of the findings.

“Intra-articular involvement of the knee should be considered in all lower extremity VMs,” Jones and colleagues concluded.