39 - Exostosis and Symptomatic Ossicles Flashcards
Medial foot prominences
Soft tissue: bursitis, tendonitis, neuritis, fibroma, granuloma, ganglionic cyst
o Play a big role in what type of symptoms occur
o Bursitis = inflammation of the bursa
o This will vary depending on the location and what anatomy is there
o Sometimes both bony and soft tissue structures will need to be addressed
Bone: arthritis, periosteal reaction, osteoma, congenital deformity, patho-mechanical deformity
Talar prominence - medial aspect of the foot
- This is caused by PRONATION, foot “splays out”
- If you have supination, it “tucks” the talar head
in and makes the talus less prominent - Can also be caused by Charcot or flat foot
in severe cases (radiograph on slides is Charcot) - Prominence produced by the head of the talus
- Prominence is exaggerated with STJ pronation
- Prominence is reduced with STJ supination
Navicular prominences
- The prominence is located just distal to a possible talar head prominence, which is virtually unaffected by subtalar joint motion
- With or without the presence of an accessory navicular
- The accessory navicular is the MOST COMMON accessory ossicle***
- Becomes apparent at age 9-11 radiographically
- THREE TYPICAL PRESENTATIONS
Type I navicular prominence
TYPE I: Represents a small ossicle just proximal to the navicular tuberosity, classified as a true sesamoid because it is within the tendon.
Type I navicular prominence
TYPE II: True accessory scaphoid appears radiographically as an extension of the navicular (its connection to the navicular is represented by a radiolucent zone which measures (1-3 mm.) The zone may be fibrous, cartilaginous, fibrocartilaginous, or partially osseous
Type I navicular prominence
TYPE III: Represents a true carnuate navicular or enlarged navicular tuberosity. (May be type II with an osseous bridge.)
Conservative treatment for a talar prominence
o Functional orthoses (MOST COMMON)
o AFO
o Shoe modification
o Steroid injection (avoid tendinous areas due to tendon weakening and rupture)
o Steroids
o NSAIDs (calm down inflammation)
o Initially offloading and resting the foot is good to get swelling down before initiating the conservative treatment options (like NSAIDS), then you can assess the next step
Surgical treatmet for a talar prominence
o Arthrodesis of the subtalar or midtarsal joint or both, tend to be the primary procedure of choice
o Adjunctive procedures may need to be considered: TN fusion, CC fusion, PCDO
Conservative treatment for navicular prominence
o Initial treatment may consist of immobilization, Nsaids, & non-weight bearing
o Shoe modification and shielding the prominence
o If secondary to severe pronation, functional orthosis may reduce symptoms
o AFO
Surgery for type I navicular prominence
o Involves removal of the ossicle from the tendon which is achieved by:
o Tendon splitting approach
o Reflection of the posterior tibialis from the talonavicular joint capsule & then removing the ossicle – if the posterior tibialis is compromised, may need to fuse joint
o May need to bring C-arm into the OR to locate the ossicle ***
Surgery for type II navicular prominence
o Adequate osseous exposure so that the entire tuberosity is visualized
o Radiolucent zone not visualized
o Intro-op (Need to probe the area to find the mobile piece of bone)
o Use radiographs to isolate location]
o Excision of the fragment is performed
o May result in weakening of the tendon and capsule
Surgery for type III navicular prominence
o Requires talonavicular joint exposure
o The subtalar joint should be supinated in order to protect the articular surface of the talar head
o Resection of the tuberosity is performed following the normal contour of the bone
Dorsal bossing
COMMONLY CAUSES PAIN
- Dorsal bossing of the 1st tarsometatarsal joint is a common acquired disorder of the foot
- Presentation at the 1st met-cuneiform joint may be a medial or dorsal prominence
- ***May be secondary to hallux limitus or hallux valgus = MOST COMMON (pronating foot)
- Another etiological agent may be Charcot arthropathy
Classification of dorsal bossing
** KNOW ALL OF THESE**
- Type I
- Type II
- Type III
- Type IV
- Type V
Type I dorsal bossing
o Dorsal exostosis formation located at the 1st met. cuneiform
o Secondary to intermittent compression of bone
o Etiology: forefoot valgus plantarflexed 1st ray (flexible or semirigid)
o NOTE: no real arthritic changes are present here
Type II dorsal bossing
o Characterized by 1st-met cuneiform joint exostosis located circumferentially (dorsal, plantar, medial) associated arthritic component of the joint itself
o Secondary to a history of trauma – patient may have a history of arthritis
o NOTE: ARTHRITIC CHANGES ARE PRESENT
Type III dorsal bossing
o Characterized by dorsal exostosis of the 1st met.-cuneiform
Angular malalignment present:
- Dorsiflexed (tendon imbalance, hallux limitus)
- Plantarflexed (pes cavus)
- Adducted (hallux abducto valgus)
Type IV dorsal bossing
o Characterized by dorsal exostosis of 1st met.-cuneiform and also involves Lis franc’s joint
o Associated arthritis within the tarsometatarsal joint
o Most common cause is Charcot arthropathy or any previous trauma
Type V dorsal bossing
o Characterized by a pseudo exostosis at the 1st met-cuneiform – there is no actual exostosis – the deformity is secondary to pes cavus foot
o The position of the forefoot will accentuate the joint, resulting in shoe irritation
Accessory bones of the foot
- Accessory bones of the foot are either normal parts or prominences of the tarsal bones that are abnormally separated from the main structure
Common symptomatic ossicles o Os vesalianum o Os peroneus o Os trigonum o Os tibiale externum
Os vesalianum
- Located at the base of the 5th metatarsal
- Pain is usually characteristic in patients with an extremely large tuberosity
- In children pain tends to be related to activity
- In adults pain tends to be related to shoe gear irritation
- NEED to get contralateral x-rays
Treatment for os vesalianum
- Initiate conservative care (shoe gear modification, etc.)
- Surgical intervention (use C-arm)
- Excision of fragment
- Possible re-attachment of peroneus brevis
Os peroneus
- Accessory bone located inferior to the peroneal groove of the cuboid.
- Encompassed within the tendon of the peroneus longus
- Actually considered a sesamoid
- Functions to assist movement of the peroneus longus (acts as a fulcrum) - REMEMBER – sesamoids ALTER FUNCTION of the tendon ***
- Usually is not symptomatic
Treatment of os peroneus
- Excision of ossicle
- Tendon repair
- Possible graft
- Tendon transfer
Os trigonum
- Accessory boney process located on the lateral process of the posterior aspect of the talus
- Usually unites or fuses with the talus by age 18
- Irritation is usually caused by the flexor hallucis longus
- Secondary to prolonged activity, trauma
Os subfibularae
Located under fibula
Os subtibialae
Located under tibia
Accessory sesamoids
- Located sub 2nd through 5th metatarsals
- Located within the long flexor tendons of each of these digits
- Never seen these sesamoids becoming problematic
CASE STUDY I
- 32 year old male presents with a chief complaint of a painful left ankle of 6 months duration
- PMHx: HTN, ankle sprains
- Meds: lisinopril, advil
- NKDA
- Vascular: DP & PT +2/4
- Neuro: epicritic sensation intact
- Musculoskeletal: +5/5 extrinsic muscles , no talar tilt, no ankle instability
- Derm: no erythema, +edema lateral ankle
Treatment:
o Immobilization in Cam boot 4 weeks
o NSAIDs
o Physical therapy
Follow-up
- Patient returns 1 year later, with a new injury to the same location
- Conservative care initiated, patient unresponsive because they were incorporated within the capsular structures
Surgical intervention:
o Removal of accessory ossicle
o Brostrom of the lateral ankle (C-shaped incision over lateral malleolus)
No problems with ossicle following surgical repair
CASE STUDY II
- 47 year old male with a chronic ulcer sub IPJ
- Approx. 2cm in diameter
- PMHx: DM w/ neuropathy, HTN, Hyperlipidemia
- Radiographs: Demonstrate an accessory ossicle sub IPJ
- Needed to be treated with surgical intervention
- Needed to surgically stabilize the toe because removal of ossicle resulted in instability
- Needed a flap to cover wound
- The area where the ulceration was eventually healed
