Primary vs Secondary Bone Healing

Primary bone healing occurs when cortical bone is touching each other and is fixed rigidly by other cortical bone or hardware. The bone fuses together by bone cones which consists of leading osteoclasts and trailed by osteoblasts forming a cone.

Secondary bone healing goes through the process similar to wound healing such as hemostasis, inflammation, callus bone formation and reconstruction to produce the same, if not better bone.

Stages of Wound Healing

There are 4 phases of wound healing:

1. Hemostasis: Clotting sequence is activated, vasoconstriction, thrombin --> fibrinogen --> fibrin. 
2. Inflammation: During this phase debris and bacteria are phagocytosed. Neutrophils then Monocyctes and Macrophages(approx 4 days after injury)  then
3. Proliferation: Angiogensis, Collogen deposition, granulation tissue formation, epithelialization and wound contraction. 
4. Remodeling: Occurs for about a year. Scar tissue regains about 2/3 or original strength but is never as strong. 

Over-drill Sizes for Lag Technique

Screw Size-->Initial Drill Size --> Glide Hole Bit Size

Non-canulated
2.7mm-->2.0mm-->2.7mm
3.5mm-->2.5mm-->3.5mm
4.0mm-->2.5mm(cancelous), 2.9(cortical)-->4.0mm
4.5mm-->3.2mm-->4.5mm
6.5mm-->3.2mm-->6.5mm

Cannulated
3.5mm-->2.7mm-->3.5mm
4.5mm-->3.2mm-->4.5mm
7.0mm-->5.3mm-->7.0mm
7.3mm-->5.0mm-->7.3mm


Synthes Reference Sheet found here: http://www.rcsed.ac.uk/fellows/lvanrensburg/classification/commonfiles/Synthes%20screws.pdf

Ankle Blocks

Ankle Blocks

Nerves blocked: Tibia N (5mL), Saphenous N, Medial Dorsal Cutaneous, Deep Peroneal N (needle advanced to bone btw EHL and EDL, 5mL), Intermediate Dorsal Cutaneous, Sural.

Mayo Block

Nerves blocked: Medial Plantar N, Saphenous N, Medial Dorsal Cutaneous N, Deep Peroneal.



Minni-Mayo Block

Nerves blocked: Lateral Dorsal Cutaneous, 4th Common Dorsal Digital, Superficial branch of lateral plantar, 4th common plantar digital N.

Ankle Sprain

Lateral Ankle Sprain Grades (Leach's Classification)

• Type1: ATFL affected
• Type 2: Complete tear of anterior talofibular lig and some damage of the CFL lig. 
• Type 3: Rupture of all 3 ligament, associated with rupture. 

O'Donoghue's Classification

1. Partial tear of LCL with mild swelling/tenderness, no mechanical instability, pt can walk, play.
2. Incomplete tear of LCL with moderate swelling/tenderness, mild/moderate instability, pt limps after injury. 
3. Complete tear of LCL with severe swelling/tenderness, echymosis, instability, pt cannot walk after injury. 

Dias Classification (1979)

Grade I: Partial rupture of CFL.
Grade II: Rupture of ATF
Grade III: Complete rupture of CFL, ATF and /or PTF.
Grade IV: Rupture of all lateral collateral ligaments and partial failure of the deltoid ligament. 

Anterior Drawer Test: Checks ATFL by pulling cal/talus forward while stabilzing tib/fib. 5-8mm drawer --> rupture of ATF, 10-15mm drawer-->rupture of ATF + CF, >15mm drawer --> rupture of ATF, CF+PTF. 

Talar Tilt: >10mm of inverstion is indicative of CFL rupture. 

Kleiger's Test: Rotate foot and dorsiflex to check for medial pain (deltoid) or anterolateral pain (syndesmosis). 

Tinel's Sign: Tapping PT nerve causes radiation in one direction. 

Ankle Fractures

Description and ID:

X-ray read points to make: Position of talus to mortis (dislocation....), syndesmotic rupture, malleoli involved (tri, bi - mal fx), displaced or not, medial or lateral clear space (>4mm =deltoid injury), medial fibulas/anterior tibia overlap (>10mm), fibular shortening, avulsions, "Shenton Line" (tibial subchondral bone lines up with small spike on fib adjacent to syndesmotic space). 

Lauge-Hanson - Ankle fractures

Classification system described by the direction of movement on the talus on tibia (Key identifies in green). 

Supination-Adduction

Stage I: Transverse fracture of the fibula below the level of the ankle joint or rupture of the lateral collateral ligaments.

Stage II: Near vertical fracture of the medial malleolus

Supination-External Rotation

Stage I: Rupture of the anterior inferior tib-fib ligament or avulsion of the ligament (Wagstaff or Tilluax-Chaput)

Stage II: Spiral fracture of the fibula with a posterior spike on the lat X ray beginning at the level of the ankle joint

Stage III: Rupture of the posterior inferior tib-fib ligament or avulsion of the ligament off the posterior malleolus (Volkmann’s)

Stage IV: Avulsion fracture of the medial malleolus or rupture of the deltoid ligament

Pronation-Abduction

Stage I: Transverse fracture of the medial malleolus or rupture of the deltoid ligament

Stage II: Rupture of the anterior and inferior tib-fib ligaments (Wagstaff or Tillaux-Chaput Fx)

Stage III: Fibular fracture at the level of the ankle joint with the appearance of a spiral fracture on the AP X ray and a transverse fracture on the lat X ray (butterfly fragment)

Pronation-External Rotation

Stage I: Avulsion fracture of the medial malleolus or rupture of the deltoid ligament

Stage II: Rupture or avulsion fracture of the anterior inferior tib-fib ligament (Wagstaff or Tilluax-Chaput) and rupture of the interosseous membrane

Stage III: Short oblique fibular fracture starting above the ankle joint and extends up the fibula depending on the extent of the interosseous rupture. Fracture runs distal posterior to proximal anterior

Stage IV: Rupture or avulsion fracture of the posterior inferior tib-fib ligament (Volkmann’s)

Danis Weber- Lateral Malleolar Fracture

Type A: Transverse avulsion fracture of the fibula beginning below the syndesmosis (SAD)

Type B: Spiral, oblique fracture of the fibula beginning at the level of the syndesmosis (SER/PAB)

Type C: Fracture of the fibula beginning above the level of the syndesmosis (PER)

Treatment:

Initial closed reduction and stabilization (posterior splint). 

DW-A --> Tension band wiring, screw/plate depending on fragment size. 

DW-B --> Neutralization plate.

ATFL should always be repaired. 

Posterior avulsion (SER 3, PER 4) repaired of >25% of joint involved. 

DW-C --> syndesosis needs to be repaired if deltoid is ruptures. 

Syndesmotic Screws --> 1x, 2x, 3.5mm or 4.5mm screws, 3 corticies or 4 corticies inserted approx 2cm above ankle joint after tapping. Removes screws usually 8-12weeks. 

21 Points of Ankle Arthroscopy

The 21-point examination was developed by Richard D. Ferkel (22) to establish a reproducible and thorough intra-articular examination of the ankle. It consists of an 8-point anterior examination, a 6-point central examination, and a 7-point posterior examination. 

8-point anterior exam:

6-point central exam:

7-point posterior exam: 

Ferkel RD, Cheng JC. Ankle and Subtalar Arthroscopy. In: Kelikian A, ed. Operative Treatment of the Foot and Ankle. New York: Appleton-Croft, 1999:321

Erythrasma

I have often heard "erythrasma" considered as a DDx when evaluating a patient with cellulitis. Here is the low down on it:

- Commonly presents in intertriginous areas of the body (skin folds, between toes, etc).
- High incidence in humid areas and in diabetic patients.
- Often is a secondary infection to tinea

- Caused by corynebacterium minutissimum
- Can dx using a woods lamp, causing it to turn corral red.
- Clinical presentation is scaling, fissuring and slightly macerated, resembling tinea.
- Common between 3rd and 4th digits (2nd interspace)

- Treated with oral Erythromyocin(binds 50S) or Tetracycline(not currently available in US).
- Relapse is common.

Big Bugs: Pseudomonus and MRSA

MRSA (methcillin resistant staph aureus) is a gram (+), catalase (+) cocci in clusters. MRSA is often sensitive to the following drugs:

• Vancomycin 500mg IV qid
• Bactrim 80/400 or 160/800 PO BID
• Linezolid 400-600mg BID

Pseudomonas is a gram (-) rod w/pili and flagella and is often sensitive to:

• Ciprofloxacin 500mg PO BID
• 3rd Gen cephalosporins 
• Aztreonam 0.5-2mg IM/IV q6-12h
• Zosyn(piperacillin/tazobactam) 3.375g IV q4-6h
• Timentin(ticarcillin/clavulanate) 3.1g IV q4-6h

Rearfoot Varus

Rearfoot Varus is when the rearfoot has a decreased amount of STJ pronation causing the calcaneus to be positioned into an inverted position.
Effects:

This leads to the foot striking the ground in a more supinated position than normal. This more supinated position requires the foot to travel a further distance to achieve necessary pronation at midfoot. This causes the medial column to slam into the ground harder than normal. This in turn fails to give the foot enough time to adequately supinate, creating a rigid lever. Inadequate supination during toe off causes a soft midfoot and can put strain on soft tissue.

If the position of the calcaneus is more inverted then this changes the pull of the

Deformities that can result secondary to a rearfoot varum include:

1. Genu Varum
2. Forefoot Valgus (caused by lateral pressure on foot). 
3. Plantar Fasciitis (caused by rapid pronation leading to high medial GRF). 
4. Hammertoes (secondary to flexor stabilization which is activated in an attempt to stablize the foot during propulsion).