Fractures of the Hand and Carpus: Complications and Their Treatment

14  Fractures of the Hand and Carpus: Complications and Their Treatment


Adnan Prsic, Jing Chen, Jin Bo Tang


Abstract


Complications arising from fractures of the hand and carpus are unavoidable in a hand surgery practice. Metacarpal and phalangeal fractures account for a large percentage of all hand fractures, while fractures of the carpal bones excluding the scaphoid are exceedingly rare and account for a low number of all fractures. The treatment for such fractures are either operative or nonoperative and both carry the risk of complications directly related to the nature of the injury and subsequent treatment. Commonly seen complications are infection and osteomyelitis, malunion, nonunion, bone necrosis, stiffness, posttraumatic arthritis, and hardware-related complications. Knowledge of the causes, indications for treatment, and major surgical techniques of such complications should be a part of every hand surgeon’s armory.


Keywords: hand fractures, metacarpal, phalangeal, carpus, complications, nonunion, malunion, surgical correction


14.1 Infection/Osteomyelitis


14.1.1 Causes


Infection in closed fractures of the hand are uncommon, but the risk is increased in open fractures given the reported incidence of open injuries to the finger from 34 to 68% among large studies.1 In addition, the extent of soft tissue damage, regional ischemia, contamination, and delay to treatment as well as inadequate debridement has been correlated with poorer outcomes and increase in infection in hand fractures.2,3 Compared to soft tissue infections in open fractures of the metacarpals and phalanges, osteomyelitis—a pyogenic infection caused by direct inoculation of the bone or untreated soft tissue infections—typically has morbid outcomes.


14.1.2 Clinical Judgment and Indication for Surgery


In our experience, nonpurulent open soft tissue infections (cellulitis) should be treated with washout and systemic antibiotics. For purulent infections of open phalangeal and metacarpal fractures with adequate washout, early administration of antibiotics has yielded low rates of soft tissue infection and osteomyelitis.4


Compared to purulent soft tissue infections in open fractures of the hand, osteomyelitis has increased morbidity. Diagnosis is established through clinical examination, radiographic imaging and obligatory bone biopsy. X-ray findings suggestive of osteomyelitis are regional osteopenia, periosteal reaction/thickening, bony lysis or cortical loss, and loss of bony trabecular architecture. Computed tomography (CT) and nuclear medicine studies can be useful, but magnetic resonance imaging (MRI) has the highest sensitivity and specificity in diagnosis. We resort to MRI in questionable cases. Positive cultures from a bone biopsy are diagnostic for osteomyelitis.


Systemic antibiotics of 4 to 6 weeks are required in the treatment of osteomyelitis and the patient must be counseled on the duration of treatment. It is very common for infection to lead to delayed union or nonunion (image Fig. 14.1). The presence of necrotic bone is a true indication for surgical removal of affected bone. Otherwise, surgeons should not aggressively remove bones, because a bony defect is a more serious problem. Poor judgment and improper surgical removal of bone can cause bony defects.



Severe infections refractory to antibiotic use for 1 or 2 months and repeated debridement, resulting in stiffness of multiple joints of a finger, may benefit from amputation. It was reported that although mild forms of osteomyelitis can be treated successfully with antibiotics, it should be noted that overall amputation rates hover around 40%.5 The percentage of amputations increases to 86% with a delay of more than 6 months from onset of symptoms to diagnosis and definitive treatment, highlighting the urgency with which the suspicion of osteomyelitis should be managed.5


14.1.3 Surgical Methods


A combined management plan of antibiotics and surgical debridement is required for treatment of osteomyelitis.5 Our treatment of osteomyelitis includes monitoring of inflammatory markers such as white blood cell count, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), irrigation and debridement of affected bone, and early antibiotic administration. Adequate soft tissue coverage is necessary. If there is a large soft tissue defect, local or regional flaps are indicated. Debridement of bone may result in bony gap which can be filled with antibiotic-impregnated polymethylmethacrylate to serve as a spacer for length and alignment for later reconstruction. Once secondary healing has concluded and infection treated adequately, the void can be filled with cancellous or corticocancellous bone graft and the fracture treated with appropriate internal fixation. We prefer fixation with plates and screws and the distal radius for donor site for cancellous bone. The olecranon, the tibial plateau, and the anterior iliac crest are also valid alternatives for bone graft donor sites.


For any fracture with internal fixation, antibiotic use and local washout should be the primary and essential treatment. Whether the internal fixation should be removed should be judged intraoperatively. If the internal fixation is firm and bony healing is not achieved, the internal fixation should not be removed. If the internal fixation is loose or bony healing is near complete, the surgeons can remove the internal fixation. After surgery, external fixation should be used. If the area of infection is extensive and open wounds left open for egress, an external fixator should be considered.


Infection may cause bony defects. Based on our clinical experience, if a bony defect is less than 1 cm, there is great likelihood of bony regeneration without a bone graft. If the defect is lengthy—1 cm or longer in the finger and carpus—a bone graft is indicated. Cancellous or cortical bone graft or allograft can be used, but the timing of surgery should be carefully planned. Usually, the local tissue should be free from infection following weeks of drainage and dressing changes after debridement or drainage of the abscess. The local bone should be further debrided up to confirmation of healthy bleeding bone before measuring the size of defect and deciding on the size of the bone graft. An iliac bone with cortical bone element is the best site for metacarpal bone defect. Alternatively, bone from dorsal aspect of the distal radius can be used, but the bone quality is usually inferior to good as that from the iliac crest. Therefore, for any larger defect, iliac bone graft should be considered, while the bone taken from dorsal distal radius is reserved for a relatively smaller defect.


14.2 Malunion


14.2.1 Causes


The bony union of a fracture in a nonanatomical position can range from minor nondisabling aesthetic concerns to severe disability for the patient. Malunion of phalangeal and metacarpal fractures can lead to remarkable angulation, longitudinal shortening, joint surface step-offs, and rotation of the bones because of failure in maintaining reduction by splinting, casting, or internal fixation. Sometimes, the malunion is the result of not having applied the proper treatment such as adequate reduction of the fracture, or timely treatment.


14.2.2 Clinical Judgment and Indications for Surgery


Phalangeal malunion varies by the location, complexity, and the nature of the deformity.6 The location can vary by digit and include proximal, middle, or distal phalanges and be articular versus extra-articular. The complexity of injury can be grouped into isolated malunion, mal-union from open fracture, malunion with prior soft tissue injury, or malunion with prior extensor or flexor tendon injury. Different approaches depend on the above factors but more so on apex volar angulation, lateral angulation, rotation, and shortening caused by the malunion.


Angulation in the phalanges is usually hard to be tolerated. Usually less than 10 to 15 degrees of angulation in the coronal plane lead to no functional loss, but sagittal angulation of 10 to 15 degrees is more problematic, and should be corrected at initial reduction. However, if malunion occurs, we must examine the patient carefully to see whether such angulation causes functional impairment. Usually, angular malunion in the coronal plane should be greater than 20 to 30 degrees to indicate corrective osteotomy.


Volar angulated malunions cause shortening of the digit greater than 30 degrees and can cause relative extensor tendon lengthening and a subsequent extension lag at the proximal interphalangeal (PIP) joint. This in turn can cause a fixed flexion contracture at the PIP joint.6,7


Patients with tolerable malunion of the metacarpals do not require operative intervention (image Table 14.1). However, symptomatic patients with disabling shortening secondary to comminution, oblique fractures, angulation, or rotational deformity should be offered surgical correction as we outlined earlier.


image




In all of the metacarpal bones, rotational angulation is less tolerable than sagittal angulation (image Table 14.1). The tolerable degrees of sagittal angulation decrease by 5 to 10 degrees moving from the little to index finger. About 1 to 1.5 cm of shortening deformity can be tolerated in all metacarpal fractures.


There is no consensus regarding the permissible step-off in intra-articular fractures in the hand. However, except for the carpometacarpal (CMC) joints in which malunion usually does not require treatment, any step-off of 2 mm would need to be corrected. Patients with articular step-offs, especially when not at the middle portion of the articular surface of the joint, can function well and allow patients to avoid surgical intervention. Development of arthritis is a slow process and if step-offs exist, the surgeon needs to carefully weigh in patients’ desire, location of the step-offs, activity levels, and age of the patient (image Fig. 14.2, image Fig. 14.3, and image Fig. 14.4).


Mechanical Data and Clinical Outcomes

A study by Strauch et al was performed on fresh frozen cadavers demonstrated a 35-degree extensor lag for a maximum shortening of 10 mm or 7-degree extensor lag for every 2 mm of shortening for fractures of the second and fifth metacarpal.8 Based on their findings it is important to consider that metacarpal shortening of 6 mm will still provide for an acceptable range of motion given that the metacarpophalangeal (MCP) joint is able to hyperextend up to approximately 20 degrees and allow motion to full extension despite an extensor lag. Severe angulation of the second and third metacarpals can contribute to weakened and painful grip as a result of the metacarpal head position in the palm.6,9 However, it is also widely believed that angular deformity and the associated shortening of the fourth and fifth metacarpal caused weakened hand grip.9,10,11 Westbrook et al studied metacarpal neck and shaft fractures of the fifth finger treated closed versus operatively.12 They established that the severity of malunion reported as palmar angular deformity did not affect the outcome of those treated nonoperatively. The disabilities of the arm, shoulder, and hand (DASH) survey, sports DASH, and cosmesis scores were significantly better in the nonoperative group compared to the operative group. The literature reports acceptable angular deformities of the second and third metacarpal from 0 up to 10 degrees while the fourth and fifth metacarpal can tolerate angular deformities of 20 and 30, degrees, respectively, without significant adverse functional outcome.6,13


Feb 25, 2020 | Posted by in ORTHOPEDIC | Comments Off on Fractures of the Hand and Carpus: Complications and Their Treatment

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