2010 Mid-America Orthopaedic Association Physician in Training Award: Healing Complications Are Common After Locked Plating for Distal Femur Fractures

Abstract

Background Several mechanical studies suggest locking plate constructs may inhibit callus necessary for healing of distal femur fractures. However, the rate of nonunion and factors associated with nonunion are not well established. Questions/purposes We (1) determined the healing rate of distal femur fractures treated with locking plates, (2) assessed the effect of patient injury and treatment variables on fracture healing, and (3) compared callus formation in fractures that healed with those that did not heal. Patients and MethodsWe retrospectively reviewed 82 patients treated with 86 distal femur fractures using lateral locking plates. We reviewed all charts and radiographs to determine patient and treatment variables and then determined the effects of these variables on healing. We quantitatively measured callus at 6, 12, and 24 weeks.The minimum time for telephone interviews and SF-36v2 TM scores was 1 year (mean, 4.2 years; range, 1-7.2 years). Results Fourteen fractures (20%) failed to unite. Demographics and comorbidities were similar in patients who achieved healing compared with those who had nonunions. There were more empty holes in the plate adjacent to fractures that healed; comminuted fractures failed to heal more frequently than less comminuted fractures. Less callus formed in fractures with nonunions and in patients treated with stainless steel plates compared with titanium plates. Complications occurred in 28 of 70 fractures (40%), 19 of which had additional surgery. Conclusions We found a high rate of nonunion in distal femur fractures treated with locking plates. Nonunion presented late without hardware failure and with limited callus formation suggesting callus inhibition rather than hardware failure is the primary problem. Mechanical factors may play a role in the high rate of nonunion. Level of Evidence Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Implant Material and Design Alter Construct Stiffness in Distal Femur Locking Plate Fixation: A Pilot Study

“…Extreme values of stiffness could potentially jeopardize the healing response of bone by providing insufficient or excessive amounts of interfragmentary movement. Findings from our study may help to explain findings of delayed healing and inhibition of periosteal callus formation in distal femur fractures fixed with stainless steel plates [10]. Highest axial stiffness values were obtained with the AxSOS and the PERI-LOC constructs, both made of stainless steel.…”

“…Clinically, locked plating systems are an established alternative to intramedullary nails [9,12,22]. However, 0% to 23% of patients will experience healing complications such as delayed union, hardware failures, and/or nonunion [10,13].…”

“…Biomechanical [4] and clinical studies [10] suggest that mechanical factors such as implant and construct stiffness are a potential cause of difficulties in fracture healing in periarticular femur fractures. Henderson et al [10] suggested stainless steel locking plates are associated with a higher percentage of nonunions than titanium plates (57% versus 43%, respectively).…”

“…Henderson et al [10] suggested stainless steel locking plates are associated with a higher percentage of nonunions than titanium plates (57% versus 43%, respectively). Many investigators have explored comparisons of distal femur locked plating systems with intramedullary nail systems [19,20,25], angled blade plates [11,24,25], dynamic condylar screws [11], and locked plating constructs with different screw configurations in the condylar fragment of the fracture model [8,16].…”

CORR Insights®: Addition of a Medial Locking Plate to an In Situ Lateral Locking Plate Results in Healing of Distal Femoral Nonunions

“…In some cases, the use of locking plates resulted in decreased callus formation [5]. Recently, nonunion of distal femur fractures treated with lateral locking plates were found to contribute to nonunions because of overly rigid fixation [3][4][5]. The analysis led to the discovery that using longer plates, and not filling the holes adjacent to the fracture site, would allow for some desirable micromotion at the fracture site.…”