Cannulok Hip System

Cannulok®Plus is the result of a continuing successful liaison between Orthodynamics, a UK based independent orthopaedic manufacturing company, and a group of dedicated surgeons. This relationship was first conceived in the early nineties, between Mr. Andrew Quaile FRCS, then practising at Southampton General Hospital, and Dr John Bradley, the then Managing Director of the company. The concept looked to utilise the technology associated with femoral nails and combine it with the potential to provide a revision hip solution in the treatment of periprosthetic fractures around either total hip or hemiarthroplasty implants. The implant design and product range have undergone significant enhancements since the Cannulok was first implanted as a straight stem with two distal locking holes. Perhaps the most notable development was the introduction of Left and Right anatomically sided stems in the late nineties. With the acquisition of the business, and subsequent integration into the Summit Medical group, considerable product development opportunities were identified for the Cannulok system. Following a Cannulok user group meeting, held in 2006 and chaired by Mr. David Ward FRCS Kingston Hospital, the outlines of the system we offer today took shape. This, combined with questionnaire feedback from a considerable number of users, confirmed the requirement for a more comprehensive product range to assist clinicians in the treatment of:

• Grossly deficient proximal femurs as a result of osteolysis.
• Femoral reinforcement where bone stock is depleted as a result of previous surgery.
• Periprosthetic fracture around the trochanteric region of total and hemiarthroplasty implants.
• Intraoperative fractures during hip arthroplasty.
• Femoral fractures complicated by metastatic bone disease.
• Paprosky IIIA & IIIB indications.

The Cannulok®Plus system, launched in January this year, is fully compliant with the Medical Device Directive’s Class III regulatory requirements due to come into force in September 2009; this makes it one of the first hip prostheses to meet the more stringent Class III criteria. A summary of the new features and benefits offered by the comprehensive Cannulok®Plus solution is detailed below: 45mm Offset:-
With the introduction of the 45mm offset, in every femoral stem size, clinicians can now be confident in more accurately replicating the patient’s anatomy and achieving improved stability. Whether the patient requires a large or small implant, there is a choice of ‘standard’ (nominal 40mm) or 45mm offset, ensuring that there is no compromise. The new 45mm offset stems also provide an increased proximal fill which increases the proximal stability of the stem, especially for Paprosky type III & IV (with impaction grafting), as well as providing a greater area for osseointegration. 360mm Length:-
The new 360mm stem, available in all stem diameters, allows secure fixation to be achieved well below the femoral isthmus, whether this is due to a distal fracture, or severe osteolysis precluding a diaphyseal fit. The 360mm stem fully complements the existing 240mm and 300mm stems, making it simple to select the correct implant, however distal the fracture may be. The Cannulok has always been available in lengths up to 400mm through a custom design service, though with increasing numbers of requests for longer stems to meet the increasing incidence of periprosthetic fractures around revision stems, there was a clear need to introduce a longer stem ‘off the shelf’. This allows this increasingly common problem to be dealt with as and when it is presented. 17mm Diameter:-
The expansion in stem diameters to 17mm completes the product range, allowing the clinical team to confidently treat an increasing number of patients whom require a large implant. This gives peace of mind that when treating any size femur, Cannulok®Plus will be the right system for a wide range of indications and patients anatomies, with distal stem diameters ranging from 11mm -17mm. Fully Coated:-
The Cannulok®Plus is now fully coated, with the full 90µm HA layer allowing better distal osseointegration, as well as increasing the rate at which progressive offloading of the distal fixation occurs. Instrumentation:-
Clearly a significant factor in the successful conclusion of every procedure, the instrumentation has been reviewed and upgraded to complement the enhanced product offering.

Custom Implant Service

For extreme revision cases and unusual anatomy, the Cannulok®Plus can be especially tailored for individual patients. Common customisations include additional and intermediate lengths (up to 400mm), different diameters and variations to the anatomic bow. The company’s experienced design and manufacturing teams have a great track record of achieving the best possible result for every patient. Upon the provision of A-P and M-L X-rays, the custom Cannulok is quickly designed with the templated plans and implant drawings being sent to the surgeon for approval. The prosthesis can then typically be ready for surgery within two weeks of surgeon approval. This lead time can be further reduced if the implant is required without HA coating and in a non-sterile condition for critical procedures.