Sprains and Strains

Sprains and Strains

Sprain – injury to ligament

Definition – disruption of ligament fibers (may be intrasubstance or bony avulsion; definition is subject to interpretation)

anatomic description depends upon degree of specificity (joint < location < ligament < fiber bundle)

Treatment Goals

(1) Early (1^st 72 hours): control bleeding (local hemorrhage, edema, pain) – RICE (Rest, Ice, Compression, Elevation)
(2) Intermediate (1^st few weeks): restore joint motion, protect healing ligament, mobilization (stretching), strengthening agonist muscles, restore proprioception (coordination), protect residual laxity (knee braces)

Remember: controlled motion cultivates organized ligament repair

(3) Late – prevent recurrent injury by establishing compensatory strength; also restore joint proprioception

Grading and Treatment – arbitrary definition of severity based upon clinical appearance (not histological/biological)

Grade I – "stretched" – disruption of small proportion of fibers; no significant loss of continuity or change in structure

especially, no joint pathological laxity

Treatment: RICE, limited rehab., no immobilization necessary; recovery takes days

Grade II – "partially torn" – altered structural properties and compromised joint stiffness – intact fibers may still be stretched

some joint laxity, but endpoint remains upon manual testing

Treatment: RICE, NSAIDS, controlled motion (with bracing), sequential rehabilitation; recovery takes weeks

Grade III – "completely torn" – enough to result in complete loss of continuity, function, and joint stability – no endpoint

Treatment: RICE is very important; temporary immobilization (cast until hemorrage is controlled), bracing during recovery, rehabilitation, surgery in some cases; complete recovery never occurs (use brace for activity)

Determinants of Healing – blood supply, environment, structural characteristics, cell characteristic, biomechanics

e.g. medial lateral ligament (MLL) vs. anterior cruciate ligament (ACL) in knee
MLL – low-frequency crimp pattern, spindle shaped fibroblasts with long processes – heals well
ACL – high-freq. crimp pattern, oval fibroblasts with short processes, hostile synovial environment – never heals

Strain – injury to muscle or tendon (usually at myotendinous junction)

Histological Progression

(1) First Days: necrosis of muscle fibers, macrophage infiltration, proliferation of inflammatory cells
(2) First Two Weeks: clearing of necrotic fibers, proliferation of granulation tissue, muscle regeneration/fibrosis (scarring)
(3) Three to Four Weeks – remodeling and restoration of normal tissue

Risk Factors for Strain Injury – weakness/fatigue, eccentric contraction (elongation during contraction), reduced flexibility, greater % type II (fast twitch) fibers, anatomical considerations (e.g., biarticular muscles crossing two joints)

Grading and Treatment – arbitrary system

Grade I – small number of fibers torn, fascia intact, microscopic injury

Presentation – minimal/no swelling or ecchymosis (bruising), tenderness at injury site, pain on resistance testing

Treatment – ice compression, oral NSAIDs, controlled progressive range of motion, stretching; no sling!

when contraction is pain free, continue strengthening and controlled progression to original activities

Grade II – larger number of fibers torn, hemorrhage, sometimes fascia torn

Presentation – "feel a pop"; pain, swelling, ecchymosis, weakness with resistance testing

Treatment – similar to Grade I – ice compression, NSAIDs, stretching

Grade III – complete rupture of muscle or tendon or tendon from bone

Presentation – severe pain, palpable defect, no effective function of musculotendinous unit

Treatment – ice compression, elevation, no steroids (they interfere with collagen), immobile/surgery sometimes

Prevention of Muscle Sprain – preparation, warm-up (pre-activation), stretching (static not ballistic/bouncing)

Overuse Injuries – injury resulting from repetitive submaximal trauma – "-itis" of any tissue

Etiology – can be intrinsic or extrinsic

intrinsic – anatomical (unequal leg length, flat feet); physiological (too much/too little flexibility); biomechanical

extrinsic – training errors (distance, intensity, terrain); equipment (worn shoes); bad technique

Overuse Injury Inflammatory Cycle

painÞ muscle inhibition Þ atrophyÞ weaknessÞ improper techniqueÞ overuseÞ microtraumaÞ hemorrhageÞ pain

can break cycle at any point – e.g. pain pills, reduce hem/edema, improve technique/strength

Treatment: the key is accurate anatomic diagnosis (i.e., don’t mistake radial nerve injury for tennis elbow)

(1) relative rest – some immobilization but mostly abstinence from activity that caused the problem
(2) anti-inflammatory – NSAIDs, cryotherapy, steroids, ultrasound/phono/iontophoresis (make steroids/etc penetrate skin)
(3) rehabilitation – stretching is extremely important – increase flexibility, restore strength, improve proprioception

Prevention – strength, flexibility training; also modify work or training schedule, equipment, surfaces, or supervision

Exercise Induced Muscle Soreness – not due to elevation in serum lactic acid

Presentation – non-acute muscle pain 12-24 hours after extended or unaccustomed high-intensity exercise

Etiology – acute inflammatory response to muscle injury – collagen degraded (elevated intramuscular OH-proline)

no lasting deleterious effect, but no scientific basis that it is benefit either (no pain, no gain?)