Orthopedic literature is remit with examples of inadvertent joint penetration, as seen above, that can lead to joint pain, stiffness, grinding, and lastly premature arthritis. “post traumatic arthritis” is well established entity but what is also well established is that some of these events are due to joint penetration by drills and screws. How can surgeons and patients avoid this?
With present drills, like you use in your garage, and x-rays surgeon rely on years of experience as anatomy experts. The concept of ‘Safe Zones’ was discussed last month (July Smartlab) rely on extensive radiation exposure for patient and OR personnel. The problem is that every patient is different in shape, size, and bone anatomy.
X-rays are just shadows of the bone. The x-ray images changes as the angle of the beam pass through the tissue and bone. Everybody has experienced how distorted some shadows can make an object look. In the morning with the sun (radiation source) on the horizon my shadow is tall and slim as it passes overhead my shadow is shorter and stout. This happens with x-ray beams too. Surgeons have to constantly be aware of potential causes for image distortion and interprate quickly and accurately the path and length of their drill bits and screws. Recent studies have suggested that 2D c-arm imagery unreliable in the most common fracture the distal radius, or wrist fracture7. A new 3D c-arm study showed continued difficulties with joint penetration detection, resolution, utility, while further increase radiation exposure times8.
Surgeons are taught generalizations of detecting joint penetration when using x-ray. For example, in a spherical joint like the hip and shoulder surgeons are taught that if the screw tip is seen in the joint on any c-arm image from the convex, or round, bone as “in the joint”. Conversely any screw tip that is seen out of the joint on multiple c-arm images on the concave side, or socket, can be considered “out of the joint”. This concept requires many c-arm images and radiation exposure events to confirm in some cases especially if the bone is osteoporotic (thin) and the patient overweight.
Making things more difficult is that most joints are not simple ball and sockets but have varied angular geometries. A recent study on placing screws and confirming their proper length with c-arm and depth gauges during ankle fusion is further evidence to the difficulty surgeon have with interpreting 2D c-arm images around the joints1,2. It also shows the variance in patient anatomy and surgeon image and wire depth gauge interpretation. Each joint has c-arm image technique studies to try to confirm safe screw placement1,2,3,4,5,6,8. These are images usually done after the screw has been placed and therefore too late the damage has been done. Many of the extreme positioning techniques also require the surgeon to be directly in the c-arm trajectory exposing the surgeon and patient to excessive radiation9.
At the end of a surgery still rely on a range of motion exam to detect “grinding” of the joint from mal-positioned bone fragments or screws. This is of course can be subtle and unreliable and if detected, the damage has already been done.
The above image is a CT- scan of the path of drill bit using SMARTdrill technology. This shows how a surgeon can stop the drill before it plunges into the joint. The surgeon also knows the exact length of screw needed. In this model the far cortex is measured at 5.3mm. This CT image is unobtainable during routine orthopedic surgery. With the commonly used 2d c-arm the surgeon would have to obtain two orthogonal images at perfect ninety degree angles and would typically use excessive radiation to complete the optimal imagery. Newer 3D c-arms are still controversial, expensive, while still using radiation8.
With SMARTdrill technology the surgeon can see the progression of the drill as cuts through the bone. If they want to stay out of the joint the surgeon just releases the dual triggers prior to the torque drop seen on the wireless Graphic User Interface (GUI), see below. Less x-ray is needed because the surgeon knows where they are three dimensionally as the slope of the torque curve correlates with the angle at which the bit is cutting into the bone just under the joint cartilage.
Less x-ray, no plunge(instantaneous or static), accurate depth measurement, 3D situational awareness, bone density, and potential pullout strength all in one revolutionary tool SMARTdrill
Ankle fusion study
1. J Hand Surg Am. 2008 Dec;33(10):1720-3. doi: 10.1016/j.jhsa.2008.07.021.
Fluoroscopic evaluation of intra-articular screw placement during locked volar plating of the distal radius: a cadaveric study.
Soong M1, Got C, Katarincic J, Akelman E.
2. Injury. 2001 Dec;32(10):783-6.
Tangential views of the articular surface of the distal radius-aid to open reduction and internal fixation of fractures.
Kumar D1, Breakwell L, Deshmukh SC, Singh BK
3. Orthopedics. 2014 Oct;37(10):e885-91. doi: 10.3928/01477447-20140924-54.
Multiple radiographic projections in detecting intra-articular screw penetration during fixation of femoral neck fractures.
Zhang L, Lin G, Yang G, Ghamor-Amegavi EP, Liu M, Pan Z, Chen S.
4. J Trauma. 2010 Mar;68(3):616-9. doi: 10.1097/TA.0b013e31819ea298.
Modified fluoroscopic imaging technique for the central screw placement in percutaneous screw fixation of scaphoid fracture.
Lee JI1, Lee YS, Cho SB, Rhyu IJ, Park JH, Kang JW, Jeon WJ, Park JW
5. J Hand Surg Am. 2010 Jun;35(6):1015-8. doi: 10.1016/j.jhsa.2010.03.041.
Use of articular wrist views to assess intra-articular screw penetration in s urgical fixation of distal radius fractures.
Pace A1, Cresswell T
6. J Hand Surg Am. 2010 Apr;35(4):619-27. doi: 10.1016/j.jhsa.2009.12.033. Epub 2010 Mar 3.
Rotational fluoroscopy assists in detection of intra-articular screw penetration during volar plating of the distal radius.
Tweet ML1, Calfee RP, Stern PJ
7. Arch Trauma Res. 2015 Jun 20;4(2):e24622. doi:10.5812/atr.4(2)2015.24622. eCollection 2015.
Tangential View and Intraoperative Three-Dimensional Fluoroscopy for the Detection of Screw-Misplacements in Volar Plating of Distal Radius Fractures.
Rausch S1, Marintschev I1, Graul I1, Wilharm A1, Klos K2, Hofmann GO3, Florian Gras M1
8. Distal radius shoot through