Eliminating a fracture is not enough to remove any doubt of seriousness after a trauma of the wrist often undermined by the practice of rugby. Indeed, a fracture – even of the scaphoid – seldom involves a potential as arthrogeneous as some intracarpian ligament lesions.
The diagnosis of sprain is still too often trivialized, whereas it is etymologically a lesion of the ligaments of the wrist requiring a topographic diagnosis and gravity as precise as a sprain of the knee for example. It is not enough to eliminate a fracture of the scaphoid (by a radiography on the 10th day) to reassure the player on the condition of his wrist. Ten bones articulate in the carpus and constitute the armature of the wrist and 33 ligaments ensure spatial coherence. The rupture of some of them is equivalent to a real “time bomb” causing an inexorable arthrosis destruction of the cartilages of the wrist.
For Watson, one of the founding fathers of “carpology” in the United States, essential osteoarthritis of the wrist does not exist and it is clear that an old trauma is almost always found in the history of a chondropathic carp. A systematic consensual attitude towards wrist injuries is essential in order to preserve the functional abilities of the players and to avoid an inexorable evolution towards osteoarthritis, a stage at which there are currently many former rugby players who did not benefit from a medical environment as efficient as the current teams.
Recall of normal and pathological physiology:
The complexity of the articular physiology of the wrist is undoubtedly for many in the darkness where the traumatic ligamentary pathology of this joint has long been plunged.
The first row of carp bones can be compared to the front row of the front pack in a rugby scrum. The arms of the hooker and of the interlaced pillars interdependent it as the interosseous ligaments (scapho-lunar and luno-triquestral) standardize the first row. Nevertheless, as in the pack (locked by the action of the second lines), ligaments are necessary to stabilize the foot of the scaphoid and the triquetrum, these are the extrinsic ligaments of the TTS (scapho-trapezo-trapezoidal articulation) and triquetro-Hamato-capital. And just as the entanglement of the opposing arms confers stability on the fray, it is the radio – and ulnocarpian extrinsic ligaments that ensure spatial coherence.
Normally, the lunatum has its two horns located in a plane perpendicular to the axis of the radius. The tilting of this plane either towards the rear (in DISI) or towards the front (in VISI) has long characterized the type of instability of the carp in the first pathological descriptions. In fact, it does not constitutes an epiphenomenon of causes that are often variable and it is better to describe the initial lesion and then its consequences on the kinetics of the wrist. The lunatum is in fact only the “carp”, which is normally balanced by antagonistic forces exerted on the scaphoid (rocking flesh like a rocking chair) or anterior rocking for the triquetrum.
Each of the ligaments of the wrist has its own pathogenicity, but it is above all the scapho-lunar ligament which has the strongest arthrogenic potential, essentially linked to the mechanical stresses exerted on the carpal scaphoid.
Natural history of the scapho-lunar sprain:
Causal trauma is rarely very demonstrative, which contributes much to its trivialization and to the fact that these lesions are too often diagnosed at a later stage. It can be a fall (often backwards in hyperflexion dorsal) or a torsional trauma.
The scapho-lunar ligament is generally affected from front to back but its lesion is not always complete. The extrinsic ligaments often participate in the initial lesional array or will relax gradually, leaving the scaphoid to deviate from the lunatum and slide in flexion. These are the first two anomalies that will be investigated in dynamic radiographs and will contribute to the progressive but early chondral degradation of the wrist (from the 3rd month of evolution).
It is not so much the difference between scaphoid and lunatum that will prove to be pathogenic but above all the rotation of the scaphoid which will then sublux to the rear of the radius and concentrate the axial stresses on a smaller articular surface, source of articular degradation fast. At the same time, the “carp – pan”, the lunatum switches to DISI but remains under the radial awning. It thus retains a homogeneous distribution of the axial forces protecting the lunar dimple of the radius from arthritic degradation for a long time. Taking advantage of the space scapholunaire thus created, the capitum gradually insinuates into the interosseous space contributing to the carpal collapse and progressive degradation of the wrist. Three progressive stages of SLAC wrist (Scapho lunate advanced collapses) are thus described:
* stage 1: isolated penile-radial osteoarthritis;
* stage 2: complete scapho-radial osteoarthritis;
* stage 3: radio-scaphoid and capito-lunar osteoarthritis.
Only an early and adapted management of these lesions makes it possible to envisage an optimal restoration of the traumatized wrist.
In front of a large traumatic wrist with normal radiography, a standardized approach is necessary to avoid serious errors. An analgesic splint and a symptomatic treatment are undertaken for 8 to 10 days before requesting a specialized clinical examination for clinical signs of ligament instability such as Watson ‘s sign indicating the subluxation of the scaphoid under the radial awning during the passage of the ulnar inclination at the radial inclination.
A high imaging balance can then be requested, usually an arthroscanner with injection of the three compartments.
If the ligament lesion is highlighted, early surgical treatment is the best guarantee of a good functional result.
Treatment is all the more severe as the stage of the lesion is more advanced: arthroscopic broaching may be indicated in early forms, but gestures of scaphoidectomy and partial arthrodesis may be necessary, a source of sequelae which could have be prevented by early diagnosis and appropriate treatment.
The articular and ligamentary physiology of the wrist being the most complex of the joints of man, it was also the last to be elucidated. Too long the functional sequelae were trivialized, it was normal to keep pain after a fracture of the wrist and we observed arthroses of the young subject without reporting them to their causal trauma that it is bone and / or ligamentary. We were the first to demonstrate the lesional associations between fractures of the radius and lesions of the intrinsic ligaments and we now know that it is more than advisable to perform an arthroscopic assessment contemporaneous with the treatment of a fracture of the radius especially in young athletes . A lesion of the scapho-lunar ligament involves a certain arthrogenic prognosis and any lesion of this ligament must be able to benefit from an early diagnosis and an adapted treatment as soon as possible, the only guarantee of minor functional sequelae not penalizing the continuation of the career of a young athlete.