The Partners
Ariaan D.P. van Walsum
Gert Nijenbanning
Arthur Aalsma
Arthur Aalsma
History
- Ariaan and his trauma surgery colleagues from the MST had participated in the PSS Hiptrial by Martin Heetveld and Ernst Raaymakers. This trial investigated the high failure rate in the surgical treatment of femoral neck fractures. Much to Ariaan's chagrin, the failure rate at the MST was just as bad as at all other hospitals in the Netherlands and abroad, namely 33-35% for dislocated femoral column fractures and 11-12% for non-dis- placed fractures.
- In his position as trauma surgeon, Ariaan regularly 'brainstorms' with Edsko Hekman of the UT Twente about possible ideas regarding innovative surgical instruments, techniques and implants, which can be further developed by UT students as graduation assignments.
- Gert Nijenbanning and Arthur Aalsma from Baat Medical, a successful Hengelo-based medical engineering ¬firm, are in contact with Edsko Hekman about the development of an innovative implant that can be developed by Baat Medical.
Perfect timing
Edsko refers Gert to Arian. And that timing turns out to be perfect!
When Gert Nijenbanning approached him about an existing osteosynthesis technique that could possibly be technically improved, Ariaan didn’t have
to think twice: the medial neck fracture! The most operated fracture with the most complications…
- The medical literature has been thoroughly studied. In the end Girdlestone showed the way: “biology is the mother of all fi¬xation”. Indeed, the bio- logy of fracture healing of the femoral neck fracture difffers from all fractures except that of the navicular fracture of the wrist. Due to the lack of the cambium layer in the periosteum of the femoral neck, fracture healing cannot take place by means of callus formation but solely by primary fracture healing, which can only take place with anatomical reposition and absolute stability of the fracture: rotationally stable, angular stable and shear stable.
- The standard implants fall short in this stability. The only motion that contributes to fracture healing is axial compression, which is achieved by dynamization of the implant.
- The fracture healing biology of the medial neck fracture also differs vascularly. In every femoral neck fracture, including non-dislocated fractures, there is a greater or lesser degree of avascular necrosis after the fracture has occurred. The survival of the femoral head depends on the degree of revascularization of the femoral head. This revascularization takes place to a large extent by endostal revascularization that crosses the fracture surface and to a lesser extent via the teres ligament.
- This vascular ingrowth is also dependent on anatomical reposition of the fracture and the absolute stability of the fi¬xation. The degree of revascula- rization of the femoral head also appears to depend on the volume of the implant in the femoral head. The greater the volume, the less the revas- cularization and the greater the risk of avascular necrosis of the femoral head. Here too the following applies: 'biology is the mother of all ¬fixation'.
Rotational stability and volume; the theory
- Why then do the current implants have such failure rates and what could be improved? For the development of the new implant it was assumed that the sliding hip screw implants could fail due to insufficient per- and postoperative rotational stability and also due to the large implant volume in the femoral head. It was also hypothesized that the multiple screw/pin ¬fixation could fail due to insufficient rotational, shear and angular stability and the large total volume of the screws in the femoral head.
- The ultimately developed Dynamic Locking Blade Plate (DLBP) is characterized by high per- and post-operative rotational stability, shear and angular stability accompanied by low implant volume in the femoral head and dynamic compression. The rotational stability of the Gannet is mainly obtained by two lateral ¬fixed wings. The fixation of the implant is obtained by two anchors that are unscrewed when the implant is placed in the head. Analogous to sliding hip screw implants, dynamic compression is obtained by sliding the implant in the barrel plate.
Practice
- After the theory came the practice. Mockups were made. A locking mechanism was devised. The first prototypes of the DLBP were tapped into pig femoral heads by Gert in Ariaan's workshop. After that, professional load tests were carried out in a national setting. This made everything very satisfying. The next fun part was developing the instruments with Arthur Aalsma
- After obtaining the CE marking, we went into the deep end. The DLBP became the Gannet after which the ¬first Gannets were placed in the MST. After that, Herbert Roerdink set up a multicenter trial, on which he eventually obtained his doctorate. His dissertation and all subsequent publications can be found on the Gannet website.
The clinical success
The clinical success
The take home message of this is that when using the Gannet, thanks to respecting the biology of the medial column fracture, a signi cant reduction in
the failure rate can be achieved for both undislocated and dislocated femoral column fractures (van Walsum et al. , 2017; Kalsbeek et al, 2016) (). Like the
natural Gannet (the gannet bird), the Gannet implant is extremely streamlined, low in volume and efective.
A.D.P. van Walsum, J. Vroemen, HMJ Janzing, T. Winkelhorst, J. Kalsbeek & W.H. Roerdink. “Low failure rate by means of DLBP Fixation of undisplaced femoral frac-tures”, European Journal of Trauma and Emergency Surgery, 2017, Vol. 43, pp. 475-480
J.H. Kalsbeek, A.D.P. van Wlasum, J/P/A.M.Vroemen, H.M.J. Janzing, T. Winkelhorst, B.P. Bertelink, W.H. Roerdink, “Displaced femoral neck fractures in patients 60 years of age or younger: results of internal xataion with the dynamic locking blade plate”, The Bone & Joint Journal, 2016, Vol. 100-B, no.4