what is talotarsal joint dislocation?
TRANSCRIPT
Primer on Talotarsal Joint Dislocation
Introduction
When it comes to the meaning of a word, there can be many opinions and assumptions.
At the end of the day, however, it’s about what can be proven.
Assumptions are not always based on fact but a on a perceived belief.
What is a Word?
A “word” is the unit of language
that functions as a principal carrier of meaning.
Dislocation
“the displacement of any part, more especially of a bone”
Dorlands Medical Dictionary
Types of dislocation:closed, open, complete, incomplete,
traumatic, congenital, compound, simple, complicated, fracture, habitual/recurrent, partial, pathologic, subluxation, luxation.
Dislocation
Dislocation
“A dislocation is a separation of two bones where they meet at a joint. A dislocated bone is no longer in its normal position, which may result in damage to ligaments, nerves, and blood vessels.” Medline Plus
Note: there is no modifier on “separation,” i.e. it does not state incomplete/partial or complete/total separation.
Historical Use of Dislocation
“ A dislocation is the displacement of one bone from another at its placed of natural articulation.” “Dislocations may be divided into accidental or traumatic, spontaneous or pathologic, and congenital.” “A complete dislocation is one in which no portions of the articular surfaces remain in contact. A partial dislocation is one in which the articular surfaces are not completely removed from each other.” Page 30
A Practical Treatise on Fractures & Dislocations – Frank Hasting Hamilton, 1863
“The word “dislocation” etymologically means ‘displacement’ (Lat. dis, a preposition, denoting separation, and locus, a place), but in surgery it is for the most part applied to that condition of a joint in which the two articular surfaces are either partially or completely displaced from one another, and no longer occupy their normal position.”
page 308
Fractures and Dislocation – Thomas Pickering Pick, 1885
Fractures and Dislocation – Thomas Pickering Pick, 1885
“Dislocations, or displacements of the articular surfaces of a joint, are divided into three classes as regards their cause. (1) Traumatic, where the displacement has been produced by violence. (2) Spontaneous or pathological, resulting from gradual destructive changes in the joint and surrounding tissues, so that the bones no longer remain in apposition, but are displaced by muscular contraction or the weight of the limb or trunk. (3) Congenital, arising from some congenital defect in the joint.”
page 308
Fractures and Dislocation – Thomas Pickering Pick, 1885
“Dislocations may be complete or partial: complete when the two articular surfaces which enter into the formation of a joint are completely separated from each other, so as to be no longer in contact; and partial when the two articular surfaces are displaced as regards their normal relation to each other, but are not completely separated, so that some portion of the one articular surface still remains in contact with some part of the other.”
page 309
Fractures and Dislocation – Thomas Pickering Pick, 1885
“The effects of a dislocation upon the structures entering into the formation of a joint, or in its immediate neighborhood, are always of importance and frequently serious. The bones, ligaments, muscles, vessels, and nerves, may all suffer.”
Page 313
Fractures and Dislocation – Thomas Pickering Pick, 1885
“When the diagnosis of dislocation has been established, the first indication is to effect reduction as speedily as possible.”
Page 322
A Practical Treaties on Fractures and Dislocations – Lewis Atterbury Stimson, 1899
“A Dislocation is a permanent, abnormal, total or partial displacement from each other of the articular portions of the bones entering into the formation of a joint.”
Page 393
A Practical Treaties on Fractures and Dislocations – Lewis Atterbury Stimson, 1899
“When the articular surfaces are so far displaced that they no longer touch each other, or that they touch only by their edges, the dislocation is said to be complete; if the displacement is less, it is called incomplete dislocation or subluxation.”
Page 393
Surgery: Bones; Joints; Fractures; Dislocations, Orthopedics;… Keen & Costa, 1907
“A dislocation is a displacement from each other of the articular ends of the bones which enter into the formation of a joint.”
“Dislocations may be divided into complete and incomplete, according to the degree of displacement.”
page 377
Textbook of Disorders and Injuries of the Musculoskeletal System – Robert B. Salter, 1970
“Displacement of a joint. When the normal reciprocal relationship between the two joint surfaces is lost, the joint is said to be displaced. The joint may be completely displaced or it may be partially displaced. In either case the joint is unstable and is associated with deformity.”
Page 27
Foot and Ankle Trauma – Barry Scurran, 1989
“Dislocation represents (disease) not to osseous joint structures or to the tendons that move them but to the soft tissues that bind them.”
Page 271
“The capsular and ligamentous soft tissues paradoxically provide the strength for joint stability and yet permit the freedom for joint motion. When the end range of motion for a joint is reached, the joint soft tissues limit further excursion.”
Page 271
Foot and Ankle Trauma – Barry Scurran, 1989
“Limitation of joint motion is further aided by joint biomechanics, osseous contours, and active muscular agonist and antagonist function.”
Page 271
Foot and Ankle Trauma – Barry Scurran, 1989
“…dislocations are radiographically evident by the incongruity of the osseous components. Postreduction radiographs or spontaneously reduce dislocation may appear “normal” because no osseous compromise or fracture has occurred.”
Page 271
Foot and Ankle Trauma – Barry Scurran, 1989
Dislocation
• is a disease process• is not normal• needs to be treated/fixed• failure to fix leads to other pathologic
conditions• Doesn’t matter if it’s a partial or full
Clinical Signs of Talotarsal Joint Dislocation
Aligned TTJ
Balanced/aligned hindfoot.Articular facets are in constant congruent contact.Minimal strain on the supporting soft tissues- ligaments/tendons.Hindfoot is in neutral/slightly pronated position.
Dislocated TTJ
Imbalanced/malaligned hindfoot.Articular facets are NOT in constant congruent contact.Excessive strain on the supporting soft tissues- ligaments/tendons.Hindfoot is in a hyperpronated
position.
Radiographic Evidence of Talotarsal Joint Dislocation
Radiographic Evidence of Talotarsal Joint Dislocation
Normal TaloTarsal Joint TaloTarsal Joint Dislocation/Displacement
“Open” sinus tarsi Partial to full obliterationof the sinus tarsi
Clinical significance: this is the easiest sign to show displacement. This immediately indicates that the talus is, at minimum, partially dislocated on the tarsal mechanism. The joints/articular facets are no longer in constant congruent contact.
Radiographic Evidence of Talotarsal Joint Dislocation
Normal TaloTarsal Joint TaloTarsal Joint Dislocation/Displacement
Normal Talar Declination Angle
Normal = < 21 degrees
Abnormal Talar Declination Angle
Abnormal = > 21 degrees
Clinical significance: an increased talar declination angle indicates a sagittal plane deformity. This creates an imbalance to the leg, pelvis and back. Also, it is directly responsible for increased strain on the medial column of the foot. This deformity occurs above the bottom of the foot.
Radiographic Evidence of Talotarsal Joint Dislocation
Normal TaloTarsal Joint TaloTarsal Joint Dislocation/Displacement
Normal navicular height Navicular drop due to the dislocation
Clinical significance: navicular drop directly leads to excessive strain to the supporting structures of the medial column of the foot such as the spring ligament, medial band of the plantar fascia and especially the posterior tibial tendon. It can also lead to disorders of the first ray/hallux.
Radiographic Evidence of Talotarsal Joint Dislocation
Normal TaloTarsal Joint TaloTarsal Joint Dislocation/Displacement
Normal cyma line Anterior plantar angulated cyma
Clinical significance: the anterior displacement of the talus forces the navicular forward. This pushes the medial cuneiform forward, which in turn pushes the first metatarsal head into the base of the proximal phalanx (hallux), leading to limited joint motion. This also unlocks the midtarsal joint leading to an excessively long period of pronation.
Radiographic Evidence of Talotarsal Joint Dislocation
Normal TaloTarsal Joint TaloTarsal Joint Dislocation/Displacement
Notice that the calcaneal inclination angle (CIA) is the same.
Clinical significance: a lower than normal CIA indicates a “flat foot” (pes planovalgus). It is possible to have a talotarsal dislocation without a “flat foot”.
Several Examples of Radiographic Evidence of Talotarsal Joint Dislocation
Normal Talotarsal Joint
Abnormal Talotarsal Joints
Normal Talar Second Metatarsal Angle
Indicator of transverse plane talotarsal alignment.
Talar Second Metatarsal Angle
• The bisection of the talus compared to the forefoot or the bisection of the 2nd metatarsal.
• The outer/upper angular range of normal is < 16 degrees.
• > 16 degrees is considered pathologic indicating a medially displaced talus on the tarsal mechanism.
Radiographic Evidence of Normal Talotarsal Joint Alignment
• Aligned talotarsal joint.• Talar second metatarsal
angle in the perfectly aligned talotarsal joint is 3-5 degrees. Anything lower than 16 degrees is considered to be normal.
Pathologic Talar Second Metatarsal Angle
Normal Abnormal
Partially Dislocated Talotarsal Joint
PosteriorFacets
Anterior/Middle Facets.
• Talar Second Metatarsal Angle (T2MA) > 16.
• Significant transverse plane deformity.
• This shows an anteriomedial talotarsal joint displacement.
Radiographic Evidence of Talotarsal Joint Dislocation
Radiographic Evidence of Talotarsal Joint Dislocation
Weightbearing image with talotarsal joint in alignment/
neutral stance position
Weightbearing image exhibiting talotarsal joint displacement/
relaxed stance position.
Clinical significance: This comparison of normal to abnormal shows a flexible dislocation of the talus on the tarsal mechanism. This is a recurrent dislocation. Excessive abnormal stain is placed on the medial column of the foot when weightbearing. Also, there are excessive forces acting on the knee and possibly the hip.
• Relaxed stance weightbearing radiograph.
• T2MA > 16.• Talotarsal joint
displacement.
Radiographic Evidence of Talotarsal Joint Dislocation
Radiographic Evidence of Talotarsal Joint Dislocation
• Relaxed stance weightbearing radiograph.
• T2MA > 16.• Talotarsal joint
displacement.
Radiographic Evidence of Talotarsal Joint Dislocation
• Relaxed stance weightbearing radiograph.
• T2MA > 16.• Talotarsal joint
displacement.
Extra-osseous Talotarsal Stabilization with internal fixation
Clinical significance: Talotarsal joint is realigned, articular facets remain in constant congruent contact. Internal fixation device allows normal/natural talotarsal motion without blocking/limiting motion. Restoration of the pathologic pre-existing deformities. Both sagittal and frontal plane correction exhibited.
Extra-osseous Talotarsal Stabilization with internal fixation.
Clinical significance: Talotarsal joint is realigned, articular facets remain in constant congruent contact. Internal fixation device allows normal/natural talotarsal motion without blocking/limiting motion. Restoration of the pathologic pre-existing deformity showing transverse plane correction with normalization of the talar second metatarsal angle.
Extra-osseous Talotarsal Stabilization with internal fixation
does not fix pes planovalgus/flatfeet.
Clinical significance: The calcaneal inclination angle is still pathologic while the talotarsal joint has been restored.
Extra-osseous Talotarsal Stabilization Type I Arthroereisis and Type II Non-Arthroereisis.
Clinical significance: Type I device is placed into the sinus tarsi so that the tip touches the bisection of the talus/lateral ½ of the sinus tarsi and functions to block or limit motion of the lateral process of the talus. Type II device is placed much deeper along with the natural oblique orientation of the sinus tarsi and functions with the natural motion of the talotarsal joint as opposed to the natural motion.
Type I Arthroereisis Type II Non-Arthroereisis
Journal of Foot and Ankle SurgeryVolume 51, Issue 5 , Pages 613-619, September 2012
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