Advances in the Canine Cranial Cruciate Ligament, 2nd edition

364 Future Directions

study in dogs (Allenet al. 2010), as well as
in select clinical cases. Cementless fixation
offers potential advantages over cemented
fixation, including elimination of bone cement
as a source of debris, preservation of peripros-
thetic bone stock at the time of surgery, and a
decreased operative time. In humans, the risk
of aseptic loosening is higher with cementless
implants compared to cemented implants, but
the incidence is not clear in dogs, perhaps
because of differences in bone quality at the
time of surgery. Allenet al. (2012) investigated
the efficacy of bioactive coating (peri-apatite,
a solution deposited form of hydroxyapatite)
in enhancing fixation of a cementless tibial
component in canine TKR. Although the coated
implants migrated significantly more than the
cemented implants within the first 12 months
after surgery, the difference was too small to
be clinically significant (Allenet al. 2012). An

all-cementless implant system has also been

developed and is currently available on the

market (GenuSys Knee; Innoplant, Hannover,

Germany). Clinical results in 22 dogs have been

reported (Behrendet al. 2013), with 16 dogs

(73%) reported as subjectively having either

no lameness or minimal residual lameness.

Importantly, 27% of dogs had unsatisfactory

results that necessitated either arthrodesis or

euthanasia.

Design rationale for the Biomedtrix

TKR implant

The BioMedtrix total knee replacement implant

consists of two elements: a femoral compo-

nent manufactured from Co-Cr alloy, and a

monobloc tibial component that is machined

from UHMWPE (Figure 44.1). A cemented

(A) (B)

Figure 44.1 (A) The BioMedtrix Canine Total Knee Replacement implant. (B) Postoperative radiographs demonstrating
successful implantation of the BioMedtrix TKR in a clinical case.