Clinical Experience with
CALLOS IMPACT and CALLOS INJECT®
Bone Void Fillers

I. INTRODUCTION
Callos is the NEXT generation of Calcium Phosphate Cement. Callos addresses the
weakest properties of the first generations calcium phosphate cements and other
biological cements. Historically, these cements have had good compression strength, but
were weak in tension, flexural strength and fracture toughness, which, combined with
poor handling properties, have limited their use in fracture fixation.

Callos has significantly higher fracture toughness values making it the first
cement capable of being drilled and screwed.

Callos may be implanted before or after definitive hardware allowing surgeons to
maintain their standard surgical routine and to create better constructs due to
precise cement and hardware placement. Callos can augment bone to provide a
better platform in poor quality bone for hardware placement

Callos is easy to mix (does not require any external mixing devices) and deliver
(the system is supplied in the kit and follows similar techniques already in use).

Callos sets quickly in ~5 minutes at 37°C in wet environment, displaces bloody
fluid and can then be drilled and screwed, if required.

Callos comes in two formulations (Inject, a paste & Impact, a putty) to provide
the surgeon with more choices.
Callos received initial FDA clearance on May 20, 2003 as a bone void filler; on
September 13 2004 for repair of craniofacial defects, burr holes and craniotomy cuts; and
on July 21, 2010 additionally cleared to be used as an autograft extender for Callos
Impact. Callos received CE mark approval and began being marketed in the UK a few
months after the first approval. In addition to the US and the European Union, Callos is
also being distributed in Australia, Korea, South Africa, with other countries being
prepared. To date Callos has been used in the US for varying applications; from the
filling of cranial defects to the treatment of fractures, for revision total joints and
oncology, including large voids, to also back-filling of the iliac crest harvest sites, and
everything in between. Additionally, Callos is the subject of several on-going clinical
studies in the US. Along with these studies, Skeletal Kinetics is actively pursuing a
clinical feedback registry from commercial cases. This document will provide a summary
of some of the clinical case studies, and a few examples of commercial cases that were
done utilizing Callos Impact or Inject calcium phosphate bone cements.
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II. CLINICAL CASES
a) Callos in the treatment of Tibial Plateau Fractures
Tibial Plateau fractures are common place in the elderly population resulting in
approximately eight percent of all fractures reported in that group. While conventional
methods of treatment yield acceptable results, patients often still report residual stiffness,
pain, instability and or deformity. Surgical treatment of tibial plateau fractures follows the
same methodology as treatment of calcaneal fractures; reduction followed by internal
fixation to maintain elevation and stability of the articular displacement. The following
radiographs show treatment of four tibial plateau fractures treated with Callos. Please
note that Callos is clearly visible on plain film x-rays when only 5 – 7 mm thickness is
remaining.
Case 1. 61-year-old female with single injury low energy trauma of lateral tibial plateau.
Open reduction and fixation with a conventional pre-formed plate and screws. A total of
10 cc of Callos Impact was inserted in the subchondral void. No problems were reported
with mixing or injection. Additionally, it was reported by Dr. Sunni Larsson (Uppsala,
Sweden) that postoperative radiographs shows that the “Impact has formed a more
homogenous structure compared with what I am used to see when using injectable
cement like Norian.” To date, patient is reported to be doing well with no complications.
At the two month visit, there was no subsidence and patient was reported to be full
weight bearing.
Pre-operative CT scan shows the depression of the articulating fragment.
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Pre-operative x-ray shows the lateral plateau fracture.
Callos
Post-operative x-ray shows the perfect placement of Callos Impact to support the
articulating fragment.
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Case 2: Woman 75 years of age with a low energy single injury. A total of 5 cc of Callos
Impact was placed in void following reduction and fixation with a conventional
preformed plate and screws. No post-operative complications reported to date.
Pre-operative CT scan shows the depression of the articulating fragment.
Preoperative x-ray shows the depression of the lateral plateau.
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Callos
Placement of Callos Impact underneath the subchondral plate of articulating joint.
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Case 3. Woman 49 years of age who was struck by a car while walking. In addition to the
tibial plateau injury, patient also sustained a simple ankle fracture and a more complex
proximal humeral fractures. Void was filled with 5 cc of Callos Inject after reduction and
placement of L-plate and screws. No subsequent complications reported.
Preoperative CT scans show the severe depression of lateral plateau.
Preoperative x-ray shows the depression of the lateral plateau.
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Callos
Postoperative x-ray shows the placement of Callos Impact.
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Case 4. Middle aged female presenting with a split depressed tibial plateau as a result of
being struck by a car. The sagittal split of the fracture was also split in the coronal plane
through the lateral plateau. The site was accessed with a hockey stick incision. The
cancellous bone was impacted all around the periphery of the void, and the articular
surface was elevated and provisionally fixated. The patient was then fixated with a
Synthes locking plate, and the void was irrigated and evacuated. Then, a 10cc Inject was
mixed per the IFU and implanted through the plate hole where the small glide screw is
placed at a diagonal. There was also a second injection through the anterior lateral screw
hole in the plate. Both injections were performed within 30 seconds under real-time
image intensification, and the screws were driven in at first under power, and then
tightened by hand within 10 minutes of injection. There was an articular defect (medial
near the tibial eminence, and was easily visualized during injection). Local cancellous
bone was packed into the articular crack prior to fixation to help minimized articular
extravasation. Wound site closure was performed immediately following injection of
Callos and screw tightening.
Callos
Postoperative X-ray shows the placement of Callos both supporting the articulating
fragment and most proximal screws.
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Callos
Lateral X-ray of the same patient.
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b) Callos in the treatment of Calcaneal Fractures
Treatment of calcaneal fractures requiring surgical intervention is typically achieved
through fracture reduction and internal fixation resulting in elevation of the depressed
articular segment. Once the fracture has been elevated an underlying void remains in the
cancellous bone. The following radiographs depict the treatment of calcaneal fractures
using Callos Bone Void Filler. Please note that Callos is clearly visible on plain film xrays when only 5 – 7 mm thickness is remaining.
10 cc Impact
ORIF with for calcaneal fracture case, AP
and lateral views, 10cc Callos Impact
implanted. Courtesy of Dr. Tonks, San
Diego, USA.
10 cc Impact
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Callos
Presented in these two pictures is a calcaneus fracture treated with ORIF and Callos. The
left picture depicts pre-operative status and the right x-ray shows the filling of the defect
with Callos after the treatment.
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Callos in the treatment of Distal Radius Fractures
Treatment of fractures of the distal radius is similar to that of fractures in the calcaneus
and tibial plateau. Fractures occurring in the distal radius requiring surgical intervention
are first reduced then stabilized using external or internal fixation. The following
radiographs depict the use of Callos in the treatment of fractures of the distal radius.
Callos is clearly visible on plain film x-rays when only 5 – 7 mm thickness is remaining.
Pre-operative X-ray shows the extraarticular displaced fracture of distal radius.
Callos
Postoperative X-ray shows the placement of Callos Inject and placement of k-wires in
Kapandgi technique.
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Callos
Callos
Lateral x-ray shows the support of both volar and dorsal fracture fragments utilizing
Callos Inject.
IV. CONCLUSION
Callos has been used in commercial and clinical study cases since it was launched in
2003. There have been no reported complications due to use of Callos in over 20,000
patients.
LBL 12084-AA
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