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Rev . Medicina Desportiva informa , 2018 ; 9 ( 4 ): 15-18 .
Disc Arthroplasty and Sports practice
Dr . Diogo Moura 1 , Dr . Marcel Sincari 2 , Prof . Doutor Fernando Fonseca 3
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Orthopedics and Traumatology Resident ; 2 Neurosurgery specialist ; 3 Director of the Orthopedics and Traumatology Department . Coimbra University Hospital Center . Portugal
ABSTRACT
Despite the increasing popularity of disc arthroplasty in predominantly young and active patients for treatment of symptomatic degenerative disc disease , currently there is still no strong scientific evidence about its benefits in comparison to classic treatment , the intersomatic fusion . Current studies , despite of some controversy , support disc arthroplasty have strict indications and is associated with a more functional and mobile spine , guaranteeing less adjacent segment disease and an earlier return to physical activities when compared to fusion . In theory , high impact , contact sports and intense activities can induce repetitive and intense axial and rotational loads to the spine and to the disc prosthesis , which can be associated with a higher risk of early arthroplasty failure . In this paper we present current scientific evidence about disc arthroplasties biomechanics rational and its clinical results and review the few studies about these implants application in athletic patients .
KEYWORDS
Disc arthroplasty , disc replacement , spine column , intervertebral disc , discopathy , sports
Disc arthroplasty – concept and biomechanics
The classical surgical treatment for advanced degenerative is the interbody arthrodesis , meagning the excision of the intervertebral disc and the fusion of the vertebral bodies with the application of cages and bone graft . Despite success on symptomatic relief , some patients develop adjacent disc disease , which consists of symptomatic degeneration of adjacent discs due to the biomechanical change of load distribution caused by the loss of mobility due to the arthrodesis of a segment , as well as the compensatory increase in the mobility of the non-arthrodesis levels . In addition , the most active patients will have lower cervical spine mobility , which can impair sports activity and quality of life . In order to by-pass this problem , the discs arthroplasties were developed , which in theory allow mobility and to recreate biomechanics , function and distribution of loads similar to normal in the affected segment and could be associated with lower disc degeneration rates of adjacent levels ( Figure 1 ). 1 However , currently the indications for disc arthroplasties are relatively restricted and a correct surgical indication is the key for success of a surgical intervention . 2
The discs arthroplasties should be applied on isolated symptomatic degenerative discopaties that do not respond to conservative treatment for six months and , generally , only in patients without structural deformities or spinal instability , in particular , without facets osteoarthrosis , and with acceptable bone quality . 2 As such , in view of the high prevalence of the counterindications referred to as the advancing age , most of the arthroplasties are performed in young patients , many of them with important activity level and expectations of a high functional level . 3 , 4 A prospective randomized multicentric compared study with 187 patients , with a two-year follow-up time , which underwent cervical disc arthroplasty , showed an increase on cervical spine mobility significantly superior than those subjected to arthrodesis (+ 5.9 ° VS-0.8 °, p = 0.001 ). Contributions to cervical spine mobility were equivalent in the various levels of patients submitted to arthroplasty , including that replaced by disc prosthesis , thus recreating a more physiological mobility , with uniform discs contributions to the total mobility arc . In turn , patients subjected to arthrodesis , contributions to total mobility were , as expected , significantly higher in the adjacent non-arthrodesis segments .
Several studies on cervical arthroplasties and lumbar discs demonstrated superior clinical-functional results and faster recovery time compared to arthrodesis . The solid fixation of the prosthesis dispiers in the vertebral bodies allows to initiate controlled mobilization in the first days of postoperative and thus start the rehabilitation early . 5-
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Despite this , due to the lack of consistent long-term results , some reviews suggest caution in the application of arthroplasties due to the risk of complications that may only arise in the long term . The prevention of the disease of the adjacent disc remains unsubstantiated and some studies have verified that a considerable portion of the disc arthroplasty develops heterotopic ossification and long-term mobility loss with no clear advantage compared to arthrodesis . 30-32
The last generation of disc prosthesis seek to recreate the anatomy of the intervertebral disc , consisting of a fibrous ring and artificial pulposus nucleus ( Figure 2 ). 33 This anatomical recreation aims to restore the biomechanics and physiological mobility of the native intervertebral disc , thus avoiding the degenerative changes occurring at adjacent levels after an interbody fusion . 33 Its application usually implies a previous approach , and can now be carried out in a minimally invasive way . After identification of the vertebral bodies , their distraction is performed and total discectomy is done . The following is vertebral endplates cruentation and , after adequate measurement of the implant dimensions , the notches corresponding to those at the prosthesis with the use of its own instrument are created in the vertebral endplates . The implant is applied in distraction and , after confirmation of its correct positioning with the use of the image intensifier , the distraction is removed in order to obtain compression . The notches and porous coating of the prosthesis seek to promote its stability and osteointegration ( Figure 2 ).
Disc arthroplasty in sportsmen
The physical exercise benefits for health are clearly demonstrated ,
Revista de Medicina Desportiva informa july 2018 · 15