Failure of fracture treatment may be related to poor inherent capacity to heal, a poor mechanical environment to promote healing, and/or tertiary causes such as infection. Understanding the underlying reasons for failure helps to choose the most appropriate treatment. Relative functional deficits are also important factors in determining future treatments. Therefore, obtaining a history of baseline function and goals for future function are critically important to optimize treatment. These factors are most important in the elderly population who often had limited function prior to their index traumatic event, or are so debilitated at the time of presentation that return to preinjury function is unrealistic.

Malunion after fracture about the hip is common. This can be related to initial malreduction of the fracture or from secondary loss of reduction. Signs and symptoms include pain, abnormal gait, weakness, and decreased range of motion. The biomechanics of the hip has been studied extensively in the setting of arthroplasty (33,34,35). Concepts such as alterations to the neck length and offset and relative coxa vara and valgus are concepts that can easily be applied to proximal femur fractures. Excessive shortening of the neck and alterations to the offset can affect the abductor moment causing gait abnormalities and weakness. Shortening can also affect range of motion and cause greater trochanter impingement. Varus malreduction of a femoral neck fracture can lead to excessive sheer forces and ultimately lead to failure. Because of the muscle attachments about the hip and the biomechanical forces, many fractures have a tendency to displace into varus.

Many of the constructs used to treat proximal femur fractures are dynamic in nature. Their inherent ability to allow
progressive compression across the fractures site has been used to increase healing rates and decrease time to union when compared to a static device. Such dynamic constructs may result in some degree of acceptable hip deformity to allow compression across the fracture site to maximize the healing potential of the fracture (33). Uncontrolled or excessive fracture collapse can lead to excessive deformity which may alter the biomechanics of the hip beyond a tolerable range. An important factor to prevent malunion is proper reduction and appropriate fixation. Some degree of gait changes and decreased range of motion is expected following treatment of proximal femur fractures with dynamic constructs and secondary intervention is rarely necessary. In young patients, when malalignment interferes with a patient’s ability to regain their maximum potential, secondary surgical procedures may be indicated to restore anatomy and hip mechanics.

The typical signs and symptoms of nonunion are a combination of pain, tenderness, and detectible motion at the site of fracture. It should be noted that symptoms of nonunion can be masked in patients with relatively stable or rigid fixation such as is seen with locked plate constructs. It is not uncommon for such patients to present with the acute or subacute onset of pain and disability associated with implant fracture subsequent to a period of full weight bearing with no or a relative paucity of symptoms. In these circumstances, the loss of stability accompanying implant failure incites the onset of symptoms. In a recent opinion poll of orthopedic trauma surgeons, the lack of ability to bear weight was felt to be the most important clinical factor in diagnosing a lower-extremity nonunion followed by fracture pain, weight-bearing status, and tenderness on palpation (36). Diagnosis of nonunion generally requires radiographic evaluation.

Posttraumatic arthritis and osteonecrosis of the hip can also be related to prior fracture. These entities are typically diagnosed with radiographic examinations. History and physical examination findings relate to progressive activity and weight-bearing–related pain and progressive joint stiffness.

Ruling out infection is generally one of the initial goals of evaluation of the patient with failure of fracture healing or failure of fracture fixation. Patient history is of little help in determining index of suspicion for infection in patients with posttraumatic problems about the hip. Since fractures about the hip are rarely open fractures, this is rarely obtained from the patient history. Local signs of infection are also often masked because of the large soft tissue envelope involved. However, a wound draining pus would certainly point to infection. Symptoms of pain can increase the index of suspicion for infection, but in the presence of nonunion or joint arthrosis, this symptom is very nonspecific. Joint aspiration, if the fracture is intra-articular, is indicated to rule out infection. This should be performed when the patient is off all antibiotics for at least 1 and preferably 2 weeks. Extra-articular fractures rely on more indirect markers of infection including serologies, namely CRP and ESR, and bone scan. Bone scan is so nonspecific that its utility in evaluation of infection associated with nonunion, is very limited. Provision for staged treatments, biopsy and culture with or without hardware removal and formal debridement as the first stage, is indicated when a high index of suspicion of infection exists. In the presence of infection, eradication of infection becomes the first priority. In the absence of infection, repair or reconstruction can be performed.