Biology of Musculoskeletal Injury and Healing- Clinical Correlations

Question 1

What is the most common mechanism of an ankle sprain and why?

Answer 1

Inversion is more common for ankle sprians because

1. The fibula bone is in the way (it is longer than tibia)
2. On the medial side of the ankle deltoid ligament complex are huge
   vs. the smaller more easily sprained ligaments(anterior talor fibular ligament, calcanear fibular ligament, posterior talar fibular ligament)

Question 2

9 year old inverts ankle playing soccer

• Now complains of lateral ankle and mid-foot pain
• On exam he has

* Diffuse tenderneess over the anterior talar-fibular ligament (ATF) and base of teh 5th metatarsal

* Non-tender over posterior ankle, negative squeeze and external rotation tests

* Pain with resisted eversion

__________________________

In addition to a classic lateral (ATF) sprain, he has?

Answer 2

5th avulsion fracture

Question 3

What are the different types of 5th metatarsal fractures?

Answer 3

Avulsion- 5th metatarsal base @ peroneus brevis insertion

Jones- Traumatic fracture metaphyseal-diaphysis junction

“Pseudo-Jones”- Stress fracture proximal diaphyseal

Dancer’s- Spiral fracture mid to distal diaphysis

Question 4

Why do you use the squeeze test (squeezing the tibia and fibular)?

Why do you do an exteranal rotation test (of the ankle)?

Answer 4

Squeeze test will result in pain either distal or proximal tibia/fibula, suggesting a fracture.

*An example is a Maisonneuve (proximal fibula) fracture

External rotation test should not increase pain in typical lateral ankle sprain. However if there is pain then you worry about an atypical ankle sprain.

* Medial pain would suggest a strained medial deltoid ligament.

* Middle pain would suggest high ankle sprain

Question 5

What tissue heals with least complete recovery?

Answer 5

Cartilage

Question 6

What should make you suspicious of joint mice (loose bodies)?

Answer 6

Locking

NOT swelling/buckling/pain/weakness

Question 7

What ligament is least likely to heal? and Why?

a. Ankle anterior talar fibular ligament
b. Ankle calcaneal fibular ligament
c. Knee anterior cruciate ligament
d. Knee medial collateral ligament
e. Thenar ulnar collateral ligament

Answer 7

ACL, knee anterior cruciate ligament,

Most inside the knee w/ the least vasculature

and

Other four have soft tissue envelopes keeping them in place. ACL is floating around free in the knee, so the ends can span large gaps.

Question 8

What does ligament healing require?

Answer 8

1. Good blood supply
2. Needs damaged section to be approximated or guided to correct area
3. Needs relative rest

Question 9

What are the stages of bony healing (and timeframe)?

Answer 9

Bleeding (seconds-minutes)

Clot formation (minutes-hours)

Inflammatory (hours-days)

Repair Stage (1-2+ weeks-3+months)

* osteoclasts and osteoblasts invade blood clot

Question 10

What are the stages of the repair stage in bony healing (and timeframe)?

Answer 10

Repair Stage (1-2+weeks-3+months)

Osteoclasts and osteoblasts invade blood clot

Soft callus (2-6 weeks)

Hard callus (4 to 12+ weeks)

Callus matures (12-26 weeks)

Bony gaps bridged (6-12 months)

Remodeling stage (1-2 years)

Question 11

What factor most influences strength of healed bone?

Answer 11

Calcium content of bony repair is the most important factor

over

Size of callus/time since initial injury/type of treatment/size of gaps on x-rays

Question 12

13 yo soccer player complains of knee pain. Denies any known injury.

Exam:

Pain to palpation of tibial tubercle

Pain with resisted knee extension

What is the underlying pathology?

Answer 12

Relative weakness of the immature skeleton compared to the mature skeleton.

Question 13

Define the following:

Diaphysis

Metaphysis

Physis

Epiphyses

Answer 13

Diaphysis-shaft

Metaphysis- area between shaft and growth plate

Physis- growth plate

Epiphyses- end of long bone

Question 14

What is Osgood-Schlatter’s characterized by?

Answer 14

Inflammation of patellar ligament on tibial tuberosity

Presents with:

Soft tissue swelling

Tibial tuberosity fracture

Pain

Question 15

What is apophysitis/pain pattern/treatments/complications?

Answer 15

Pain and inflammation of ossification centers from repetitive tension.

Pain pattern can be: 1. after activity 2. at the beginning of activity 3. throughout activity. 4. all the time

Treatments: Activity as tolerated, stretching, ice, NSAIDs

Complications: Bony hypertrophy; fracture (rare)

Question 16

What are common sites for apophysitis?

Answer 16

Osgood-Schlatter- tibial tubercle

Sever’s- Calcaneal apophysitis

Sinding-Larsen-Johansson- Distal patellar pole

Anterior superior iliac spine (ASIS)-Sartorius

Anterior inferior iliac spine (AIIS)-Rectus femoris

Little leaguer’s elbow (medial epicondyle)