The subcutaneous tissue is usually a part of the examination at the time of a skin injury. In most closed injuries, this will never be a concern other than in avulsion injury of the subcutaneous tissue from the fascia layers (Morel-Lavallee injury) [17]. This is usually diagnosed by palpation of the extremity around the injury and feeling a boggy or fluid-filled area under the skin. This is an occult lesion and may not be recognized for days. It is a hidden area for serosanguineous fluid collection or occult blood loss. Its management will depend on the underlying fracture and the need for operative intervention. As these areas can be contaminated by hematogenous spread of organisms, it may be wise to drain these open or percutaneously and culture. When healed, it would be safe to operate the fracture. If found when approaching a fracture, it is best to debride, culture, and then fix the fracture, but the area must be drained.

During debridement of an open fracture or at the time of fixation of a closed fracture, the subcutaneous tissue maybe found to be completely crushed and dead with dead or poorly viable skin overlying the area. These areas will usually go on to break down and required local debridement. If at the acute debridement of an open fracture fixation the area can be safely debrided and closed, it is wise to do so as to avoid later complication. This will hold true in a closed fracture undergoing operative treatment as well. If debridement will compromise coverage of fracture fixation, then flap coverage will be necessary and it may be advisable to wait out the natural evolution of this soft tissue injury. These decisions all require experience in soft tissue assessment and handling. However, the ultimate decision should be documented as further excision, even amputation, may be required, depending upon the patient, the condition, and the methods of treatment.

Assessment of the muscle is a critical aspect in any musculoskeletal injury. The reason for this is that muscle provides the most amount of blood for the area for healing and for the prevention of infection. Also, muscle is responsible for function, and with muscle damage and loss, ultimate function deteriorates, and patients’ outcomes are less than ideal. Consequently, the assessment of the muscle viability in any open injury should be made at the time of debridement. At this point one must look at its color and its consistency in that it is soft and not hard or firm. This feel for consistency is important as muscle dies from the inside out. A muscle may demonstrate contacting fibers on its surface, but the core is dead. This muscle will generally have a firm or rubbery feel, while that muscle that is alive will feel soft throughout. Should the muscle have this rubbery firm feel, it is important to split the fibers and assess the deeper layers for muscle death. This muscle may not be excised at this time, but it is an indication for the need for a repeat look to assure no further death has occurred. Muscle contractility is best tested by tapping on the muscle with an instrument or the finger and seeing it contract, or by touching it with a cautery and seeing the contraction. Circulation can be checked by observing the muscle for punctate bleeding points indicative that the intricate vasculature that is providing blood supply is intact [18].

The assessment of muscle in a closed injury is at the present time extremely difficult. There are few clinical tools able to assess the viability or vascularity of muscle on a routine clinical basis. Certainly the role of compartment pressure measuring for compartment syndrome is one way of indirectly measuring the vascular supply or viability of muscle but is only used in those conditions in which one is suspecting the compartment syndrome. However, the more common circumstance is the significant high-energy injury or crush injury and particularly those with complex, closed fractures in the metaphyseal region. This leads to significant swelling of the muscle and ongoing swelling of the soft tissues. This has led to the concept of damage control limb surgery in which the use of external fixation is applied to maintain the leg to length as well as the bone and provides stability to the soft tissues to allow them to heal, revascularize, and be prepared for surgical intervention, minimizing the complications [19].

Nerve injuries can range from annoying in the case of cutaneous nerves to devastating loss of sensory and motor function. Without ongoing functional nerves, muscles will not function and patient outcomes will be poor. However, nerves injured in continuity will tend to return to function with time. An assessment of the neurological status of the upper and lower extremity is imperative with every injury. It is important to document injury but more important to assess and document ongoing neurological loss which may stimulate further acute emergency treatment to prevent nerve loss. The majority of nerve injuries in closed fractures are usually some form of contusion and rarely a laceration. The standard management has been to decrease compression by reduction of the fracture. There has been no proof that there is a need to explore a nerve injury in closed fracture as an acute treatment. Certainly at the time of operative fixation if the nerve is injured and is readily accessible, then exploration is warranted. However, in open fractures with nerve injuries, part of the debridement process is to explore the nerves in the area if injured and determine what has transpired and treat accordingly [20].

Vascular injury is associated with a fracture. It is an acute situation which requires the treating musculoskeletal surgeon to have in the back of his mind a plan that can be implemented quickly. In fact, it is imperative that in any institution that will manage these injuries that there should be protocols developed between the musculoskeletal surgeon and vascular surgeon to assure that prompt, adequate assessment and treatment is carried out [21]. The first form of assessment is the monitoring of the distal pulses from the injury. Obviously if these are equal to the opposite side, there is probably little evidence of any injury. If they are not present or decreased, one must then look at the perfusion distal to the fracture and assess if this is compromised. This assessment is done through functional evaluation of both neurological injury and muscle function as well as capillary refill. If both nerve and muscle function are intact, then there is enough perfusion to that extremity that investigations may be carried out to assure that one has made diagnosis of the vascular injury and knows what is happening. However, if there is no perfusion to the distal segment and it is cold and pulseless, with no neurological function and no muscle function, this is an acute emergency which requires prompt action. The management of this acute injury requires from the orthopedic surgeon a reduction of any deforming forces across the artery. This usually means a closed reduction and splintage of the fracture. Following this, a reassessment of the pulses is performed. If pulses do not return in the majority of isolated injury circumstances, one can make the decision that the vascular injury is at the site of the fracture. There is little need to waste time looking or determining where it is and obtaining arteriography to do this. However, if there are multiple injuries to the leg or if one is unsure of oneself, then the use of arteriography or contrast enhanced computer tomography (CT) is extremely helpful in quickly determining the lesion location. In the acute situation with acute vascular injury, an arteriogram may be done on the operating table by injecting the dye through femoral artery for the lower extremity or the axillary artery for an upper extremity injury. This is a procedure done by vascular surgeons which is helpful to determine the level of injury. In the operating room, the vascular surgeon and orthopedic surgeon need to work as a team to assure the appropriate debridement and exposure that allows both to work and that also will manage the injury of the bone correctly and at the same time allow prompt revascularization. This may mean that the orthopedic surgeon goes first or the vascular surgeon, but this is a team approach and needs to be discussed with the qualified individuals at the time of treatment. There are many ways of handling this such as temporary external fixation followed by vascular repair then the appropriate definitive fixation of the fracture, external fixation with vascular repair and delayed definitive fixation, vascular repair, followed by definitive fixation or external fixation. All these choices need to thought out and planned by both surgeons. One must also remember that after 6 h of cold ischemia time, serious consideration must be given to the use of fasciotomies distal to the arterial repair. Within 6 h of complete ischemia, reperfusion of the muscle will lead to significant swelling and potential for a compartment syndrome. As these patients are critically ill and tend to be intubated and monitoring of their compartments is difficult if not impossible, the use of prophylaxis fasciotomies is highly recommended in this circumstance to prevent limb loss or muscle death and poor function [22, 23].

A compartment syndrome is the death or compromise of viability of muscle secondary to closure of the capillary beds of muscle in any contained area in an extremity [24]. The causes of a compartment syndrome are many. Consequently, what must be remembered is that for any injury to an extremity, the treating surgeon must rule out a compartment syndrome. This first is done on a clinical and physical examination basis. Because the muscle has a decreasing blood supply, the muscle itself responds by becoming increasing irritable which means that it is painful. In fact, as the swelling increases, it becomes excessively painful and feels like the leg will be bursting. One might describe this as a “heart attack of skeletal muscle.” Hence, the most common symptom of compartment syndrome is pain out of proportion to what one would expect with the injury and also excessive use of analgesic medication. Physical exam is helpful in diagnosing a compartment syndrome, but one must be wary of the findings. The common method of testing compressibility of the injured limb is extremely subjective. Although a very tense hard compartment is easily recognizable, something between that level and soft compartments may be difficult to determine and hence mislead the treating physician. Pain with passive stretch is difficult to interpret secondary to the fracture site pain and irritation due to damaged muscle. If truly present, it is a definitive sign of this condition. Loss of pulse, paresthesia, and neurological injury are all indicative of a compartment syndrome but occur as the end result of the damage secondary to loss of vascularity. Decreased sensation and nerve function usually indicate that permanent damage has already occurred and hence treatment is too late. In alert and oriented patients, the diagnosis is made on clinical grounds and a high degree of suspicion for this condition. Should doubt exist or the patient is noncooperative due to injury, drugs, intoxication, or anesthesia, compartment pressure measurement is a technique that is useful to confirm the diagnosis. There are many monitors and one should choose one that is easily available, and the surgeon knows how to use. The accepted pressure level for decompression is usually the difference (Delta P) between the diastolic blood pressure and the compartment pressure. This must be less than 30 mmHg. This method is important because it takes into account the patient’s physiological circumstance such as hypotension or hypertension [25].