Moximed said today that it pulled in a $33 million Series B round for its KineSpring knee implant, which is designed to reduce the load on the joint while sparing its anatomy.

The Hayward, Calif.-based company said new backer Vertex Venture Holdings joined prior investors New Enterprise Assoc., Gilde Healthcare Partners, Morgenthaler Ventures and GBS Venture Partners in the round.

Dr. Christopher Shen, Vertex’s U.S. healthcare head, is slated to join Moximed’s board as part of the funding, the company said. Moximed has raised $105 million total, including the Series B, a company spokesman told MassDevice.com.

"Vertex shares Moximed’s vision of the vast opportunity to make joint unloading a standard of care for osteoarthritis patients. A procedure that could potentially avoid or delay joint replacement and costly revision arthroplasty surgeries would appeal to all stakeholders: patients, surgeons, payers, and employers," Shen said in prepared remarks.

KineSpring is designed to be implanted under the skin along the knee joint in mild to moderate osteoarthritis patients who aren’t responding to pain meds and bracing but aren’t ready for a full-on knee implant, Moximed said. The device won CE Mark approval in the European Union in 2009 and is in an investigational device exemption trial called Soar in the U.S.

"We are excited to add Vertex as a new investor, and we gratefully appreciate the continued support of our previous investors. The new capital will support the company’s efforts to gain FDA approval of the KineSpring system and grow commercial sales in Europe," CEO Kevin Sidow said in a press release. "We continue to be encouraged by the relief brought to patients worldwide by the KineSpring System and by the strong interest in a joint preserving treatment that allows patients to maintain the lifestyle they expect and deserve."