Introduction

Acute compartment syndrome (ACS) remains a clinical emergency that occurs in orthopaedic trauma practice. ACS continues to present orthopaedic surgeons and other clinicians with diagnostic and treatment challenges. Evaluation of patients with suspected ACS must be prompt and fasciotomies, if needed, must be rapidly performed.

I. Preoperative

1. 
   

   Risk factors for ACS

   
   
   
   
   1. 
      

      Tibia fractures are most commonly associated with ACS, followed by soft-tissue injuries and finally forearm/wrist fractures.

      
      
   2. 
      

      When looking at all the causes of ACS, sport-related injuries lead to the highest total number of ACS cases (~ 25%).

      
      
   3. 
      

      Many other causes of ACS have been reported including bleeding, burns, intravenous (IV) infiltrations, intraoperative positioning, compressive dressing or casts, reperfusion injury, high-pressure injection injuries, and drug overdoses (prolonged pressure on dependent compartment).

      
      
   4. 
      

      Incidence of ACS with specific injuries:

      
      
      
      
      1. 
         

         Tibia shaft fracture: 3%–10%.

         
         
      2. 
         

         Tibial plateau fracture: 12%.

         
         
      3. 
         

         Bicondylar plateau fractures and medial condyle fracture-dislocations: up to 30%.

      
      
   5. 
      

      Multiple studies have shown younger age to be a major independent risk factor. Ages from 10 to 30 years tend to be the strongest predictor for ACS.

      
      
   6. 
      

      Civilian ballistic injuries have a reported low rate of ACS (~3%). However, isolated fibula and isolated tibia ballistic injuries have ~11% reported incidence of ACS. Proximal injury location accounted for nearly 90% of the cases.

      
      
   7. 
      

      Open fractures are not protected from ACS. Most series show an increase in ACS when open fractures are compared to closed.

   
   
2. 
   

   Diagnosis

   
   
   
   
   1. 
      

      Diagnosis is difficult and rates of ACS diagnosis can vary from surgeon to surgeon within the same institution treating the same injuries (surgeons ranged from 2% to 24% in ACS diagnosis and treatment).

      
      
   2. 
      

      Exam in ACS

      
      
      
      
      1. 
         

         Clinical exam is considered the gold standard for diagnosis, and unless a reliable exam is not possible (obtunded patient, head injury, intraoperative, etc.) other diagnostic modalities are not indicated.

         
         
      2. 
         

         Classically, the five Ps have been incorrectly applied to ACS exam and diagnosis (pain, pallor, pulselessness, paresthesias, and paralysis). These were initially described for arterial insufficiency and are not very accurate for ACS. The vast majority of ACS patients have normal pulses.

         
         
      3. 
         

         Typical exam findings include:

         
         
         
         
         • 
           

           i. Pain out of proportion.

           
           
         • 
           

           ii. Pain with passive stretch of the muscle in the affected compartment.

           
           
         • 
           

           iii. Paresthesias.

           
           
         • 
           

           iv. Anesthesia or decreased sensation.

           
           
         • 
           

           v. Muscle weakness or paralysis.

           
           
         • 
           

           vi. Tense compartment on palpation—be aware as palpation of compartments alone has a low sensitivity and specificity in diagnosis of ACS (24 and 55%, respectively).

      
      
   3. 
      

      Intracompartmental pressure measurements (ICP)

      
      
      
      
      1. 
         

         ICP is the current standard for diagnosis when exam is questionable or not possible.

         
         
      2. 
         

         Pressures have been shown to be highest at the fracture site and dissipate with increasing distance from the fracture.

         
         
      3. 
         

         Most clinicians recommend measuring the ICP close to the fracture site.

         
         
      4. 
         

         Classic dogma uses ∆P measurement < 30 mm Hg for diagnosis.

         
         
         
         
         • 
           

           i. ∆P is calculated by subtracting the ICP from the patient’s diastolic blood pressure prior to anesthesia (if being done in the operating room). Theoretically as this number approaches 0, the perfusion decreases in the compartment.

           
           
         • 
           

           ii. ∆P > 30 mm Hg is a very conservative threshold. Clinical studies show this to be a safe threshold; however, it may lead to overtreatment.

           
           
         • 
           

           iii. False positive rates of 35% in operative tibia fractures (no ACS when ICP measured).

         
         
      5. 
         

         Typical modern devices used for pressure measurement include slit catheter (▶ Fig. 13.1a ), side port needle (▶ Fig. 13.1b ), solid-state transducer intracompartmental catheter (STIC), electronic transducer tipped catheter, and arterial-line transducers.

         

         
         
         
         
         • 
           

           i. These methods are fairly similar in their pressure measurements (0.83 correlation). However, ~30% of the time the differences can exceed 10 mm Hg between these devices.

           
           
         • 
           

           ii. The invasive portion of the device (slit catheter, side port needle, 18-guage needle) in early literature showed the side port to be superior; however, more recent studies suggest that an 18-gauge was as accurate as the others.

         
         
      6. 
         

         There is a concerning variability in pressure measurements clinically. In one study, 60% of clinicians measured ICP within 5 mm Hg of the control ICP.

         
         
      7. 
         

         The use of continuous pressure monitoring is still being evaluated. To date, all studies that have compared continuous monitoring to clinical monitoring with noncontinuous ICP measurements have not shown a difference in outcome or delay in treatment.

      
      
   4. 
      

      Other diagnostic modalities

      
      
      
      
      1. 
         

         Near-infrared spectroscopy (NIRS):

         
         
         
         
         • 
           

           i. NIRS relies on the difference in absorption of near-infrared wavelengths of light (600–1,000 nm) in biologic tissue. The wavelengths can pass through skin, soft tissue, and bone but are absorbed by hemoglobin and can determine its oxygenation state.

           
           
         • 
           

           ii. NIRS is a noninvasive and rapid assessment of tissue oxygenation that has future promise.

           
           
         • 
           

           iii. To date, the literature is mixed on the accuracy in diagnosis of ACS.

           
           
         • 
           

           iv. Large trials are ongoing to determine its effectiveness.

         
         
      2. 
         

         Biomarkers:

         
         
         
         
         • 
           

           i. Serum levels of creatine kinase (CK) > 4,000 U/L, Cl >104 mg/dL, and blood urea nitrogen (BUN) < 10 mg/dL have been shown to be significantly correlated to ACS; however, the ability to aid in diagnosis is unclear.

           
           
         • 
           

           ii. Lactate levels have been evaluated in vascular patients with an acute embolism, the relevance in ACS needs to be evaluated.

           
           
         • 
           

           iii. Intracompartmental glucose concentration and pH have been shown to be significant markers in experimental animal models only. Clinical data is lacking.

         
         
      3. 
         

         Ultrasonography:

         
         
         
         
         • 
           

           i. Pulsed phase-locked loop ultrasound uses reflection off fascial planes to identify a characteristic waveform from local arterial pulsation that is altered in ACS.

           
           
         • 
           

           ii. Preliminary research shows this may be effective in the future.

         
         
      4. 
         

         Other methods:

         
         
         
         
         • 
           

           i. MRI, scintigraphy, and laser Doppler flowmetry are some of the other diagnostic tools purposed for ACS diagnosis.

           
           
         • 
           

           ii. Drawbacks related to these modalities include decreased specificity, limited availability, cost and increased time required to evaluate patients.

           
           
         • 
           

           iii. As of now they have no role in diagnosis of ACS.

   
   
3. 
   

   Radiographic correlations with ACS

   
   
   
   
   1. 
      

      The odds of ACS in tibia fractures increases by 1.7 per 10% increase in the ratio of fracture length to total tibia length.

      
      
   2. 
      

      Initial femoral displacement ratios (> 8%) (displacement with respect to the tibia divided by femoral condylar width) have a significant correlation with ACS in plateau fractures.

      
      
   3. 
      

      Initial plateau widening (> 5%) after plateau fracture has been associated with ACS.

   
   
4. 
   

   Compartment anatomy

   
   
   
   
   1. 
      

      Leg—four compartments (▶ Fig. 13.2 )

      

      
      
      
      
      1. 
         

         Anterior—tibialis anterior, extensor digitorum longus, extensor hallucis longus, peroneus tertius, anterior tibial artery, and deep peroneal nerve.

         
         
      2. 
         

         Lateral—peroneus brevis, peroneus longus, and superficial peroneal nerve.

         
         
      3. 
         

         Deep posterior—tibialis posterior, flexor digitorum longus, flexor hallucis longus, tibial nerve, peroneal artery, and posterior tibial artery.

         
         
      4. 
         

         Superficial posterior—gastrocnemius, soleus, popliteus, plantaris, and sural nerve.

      
      
   2. 
      

      Thigh—three compartments

      
      
      
      
      1. 
         

         Anterior—sartorius, rectus femoris, vastus lateralis, vastus intermedius and vastus medialis, articularis genus, femoral nerve, and femoral artery.

         
         
      2. 
         

         Posterior—biceps femoris, semitendinosus, semimembranosus, profunda femoris, and sciatic nerve.

         
         
      3. 
         

         Adductor—pectineus, external obturator, gracilis, adductor longus, adductor brevis, adductor minimus, and adductor magnus.

      
      
   3. 
      

      Gluteal—typically considered three compartments: (the compartment can also be considered the epimysium over these large muscles) tensor fascia lata, gluteus medius and minimus, and gluteus maximus.

      
      
   4. 
      

      Foot—traditionally considered to be nine compartments. The medial, superficial, and lateral compartments run the length of the foot. The adductor and four interossi compartment are in the forefoot and calcaneal compartment is in the hindfoot.

      
      
      
      
      1. 
         

         Four intraosseous compartments.

         
         
      2. 
         

         Medial—abductor hallucis and flexor hallucis brevis.

         
         
      3. 
         

         Superficial (or central) compartment—flexor digitorum brevis, flexor digitorum longus tendons, and four lumbricals.

         
         
      4. 
         

         Calcaneal—quadratus plantae.

         
         
      5. 
         

         Adductor—adductor hallucis.

         
         
      6. 
         

         Lateral—flexor digiti minimi brevis and abductor digiti minimi.

      
      
   5. 
      

      Forearm (▶ Fig. 13.3 )

      

      
      
      
      
      1. 
         

         Anterior (volar)—flexor carpi radialis, palmaris longus, flexor carpi ulnaris (FCU), pronator teres, flexor digitorum superficialis (FDS), flexor digitorum profundus (FDP), flexor pollicis longus (FPL), pronator quadratus.

         
         
      2. 
         

         Dorsal—extensor carpi ulnaris, extensor digitorum, extensor digiti minimi, abductor pollicis longus (APL), extensor pollicis longus (EPL), extensor pollicis brevis, extensor indicis, and supinator.

         
         
      3. 
         

         Mobile wad—brachioradialis, extensor carpi radialis brevis (ECRB), and extensor carpi radialis longus (ECRL).

      
      
   6. 
      

      Arm

      
      
      
      
      1. 
         

         Anterior—coracobrachialis, biceps brachii, brachialis, brachial artery, ulnar and median nerve.

         
         
      2. 
         

         Posterior—triceps, anconeus, and radial nerve.

      
      
   7. 
      

      Deltoid.

      
      
   8. 
      

      Hand (10 total).

      
      
      
      
      1. 
         

         Hypothenar, thenar, adductor pollicis, dorsal interosseous (× 4), palmar interosseous (× 3).

         
         
      2. 
         

         The carpal tunnel should be included in decompression.