Blue Belt Technologies Receives CE Mark for Navio PFS System

Blue Belt Technologies, Inc., a medical device company focused on developing the next generation of "smart" surgical instruments providing precise robotic control for use initially in orthopedic procedures and then for other surgical specialties including neurosurgery, spinal and otolaryngology ("ENT"), announced today that it has received CE Mark for the Navio™ PFS System.

The Company's initial market application in Europe is for Unicondylar Knee Replacement ("UKR") which is commonly known as partial knee replacement. A partial knee replacement is surgery to replace either the inside (medial) or outside (lateral) compartment of the knee with an implant. Partial knee replacements are bone-sparing and have been shown to provide better surgical outcomes for patients with cartilage damage contained to a single compartment when compared to total joint replacement. The majority of partial knee replacement surgeries are currently performed using instruments which can be inconsistent and lead to high revision and retreatment rates.

Technique, patient and implant selection key to avoiding fracture during THA

At the Current Concepts in Joint Replacement 2011 Winter Meeting, Craig J. Della Valle, MD, provided tips on the prevention of intraoperative fractures during total hip arthroplasty.

“Prevention is key,” Della Valle said, noting that appropriate exposure is crucial.

In a study of more than 5,000 hip replacements performed by 11 surgeons during a 10-year period, Della Valle and colleagues found that risk factors for fracture include elderly patients, female patients and type of stem used. He noted that flat-wedge taper designs have a high risk for early postoperative and intraoperative fracture. Developmental dysplasia of the hip was also substantial risk factor.

The decision to use a cemented or uncemented implant is also key.

Hip resurfacing: The metal-on-metal bearing material is not the problem

The success of total hip replacement (THR) in the 20th century has been tremendous with improvements in the durability of new designs, bearing materials and fixation techniques. However, the young and active patients have historically had high revision rates compared with older, more sedentary patients, notably when the etiology of the disease is osteonecrosis. Despite great improvements in cementless stem fixation, hip resurfacing arthroplasty (HRA) has the advantages of replicating leg length and offset, and maintaining proximal bone unlike THR. Moreover, dislocation in THR remains a problem when small femoral heads are used. Resurfacing patients also do not report thigh pain as it sometimes happens after THR.

When it comes time for revision surgery, as should be expected for most young and active patients, whether treated with a resurfacing or a primary THR, the preserved bone stock with hip resurfacing provides more favorable conditions for a successful surgery and the technical difficulty of the conversion is comparable to that of a primary THR. This enables patients seeking to restore their previous lifestyle to be more active than with a THR, and numerous authors have reported high levels of physical activity in patients after hip resurfacing.

Ceramic femoral heads generated less linear polyethylene cup wear over 20 years

German researchers concluded after two decades of investigation that ceramic femoral heads create less linear polyethylene cup wear over time compared with metal heads.

While the cobalt-chromium-molybdenum (CoCrMo) group showed a mean 0.190 mm/year wear rate in the long-term study – which examined long-term wear analysis of femoral heads over a 20-year period – the ceramic head group had a 0.107 mm/year wear rate, which caused “significantly less osteolysis and revisions of either component,” the authors wrote in the abstract. The paper was published in Seminars in Arthroscopy.

In 80 patients, surgeons performed 93 consecutive uncemented hip arthroplasties using a titanium-coated cup and cementless stem. Eighty ceramic and 13 CoCrMo 32-mm diameter femoral heads were used. On average, patients followed up for 19.3 years and no patient was lost during follow-up, according to the abstract.

At AAOS 2012: Biomet Debuts Personalized Approach for Partial Knee Replacements

At AAOS in San Francisco, Biomet Orthopedics launched its Signature personalized patient care system designed for use with its Oxford partial knee system. The Signature custom positioning guides enable orthopedic surgeons to create custom femoral and tibial surgical positioning guides to facilitate precise joint implant positioning.

The Oxford partial knee procedure is designed to enable roughly 75% less bone and cartilage to be removed than total knee replacements. The patient-specific positioning guides are created using MRI data.

—Brian Buntz

Melting down hips and knees: The afterlife of implants

As people live longer and medical technology improves, more and more of us will have a surgical implant before we die. We are also getting cremated in larger numbers - and so there is often some expensive metal left among the ashes. Where does it go?

"You tell people what you do, and they think... well, that's a bit strange," says Ruud Verberne above the din of giant sorting machines twirling and clanking.

Verberne is co-founder of OrthoMetals, which recycles metal implants from cremated human bodies. That's everything from steel pins to titanium hips and cobalt-chrome knees.

These are the knees that we have to recover," he says. "Some metals can be sorted by magnets. And the remaining have to be sorted by hand."

Zimmer introduces Chondrofix Osteochondral Allograft

Zimmer Holdings Inc. released its Chondrofix Osteochondral Allograft to repair osteochondral lesions in diarthrodial joints in a single-stage procedure.

“Chondrofix technology offers an innovative new option for early intervention treatment of cartilage lesions through either an open or arthroscopic surgical procedure,” Cheryl R. Blanchard, PhD, senior vice president and chief scientific officer at Zimmer, stated in a company press release.

According to the release, the allograft is designed for patients with osteochondral legions who are considered too young for a total joint replacement or need to reduce the amount of rehabilitation time. It is minimally manipulated using a proprietary process which results in viral inactivation and terminal sterilization. The product also has a 2-year shelf life, and retains the mechanical properties of the pre-processed tissue, including the capacity for immediate load-bearing.

Surgeons Using Metal-Alloy Allergy Tests to Screen Patient Candidates for Total Hip or Knee

Preoperative skin patch testing for metal allergy influenced treatment planning in two-thirds of a small cohort of patients scheduled to receive metal-containing prosthetic devices, a retrospective chart review showed.

All 21 patients with positive tests received allergen-free prostheses and had no complications associated with hypersensitivity.
Post-implantation patch testing led to prosthesis removal in 10 additional patients, and six had resolution of hypersensitivity-associated symptoms.
“The findings of this study support a role for patch testing in patients with a clinical history of metal hypersensitivity before prosthetic device implantation,” Natasha Atanaskova Mesinkovska, MD, PhD, of the Cleveland Clinic, and co-authors wrote in an article published online in Archives of Dermatology.