What Is the Likelihood of Union After Coronal Limb Realignment Using Revision Osteosynthesis and Concurrent TKA in Patients with Advanced Arthritis and Loss of Fixation After Distal Metaphyseal Femur Fractures?

Abstract

Background Metaphyseal fracture healing in the distal femur requires a stable biomechanical environment. The presence of arthritis-induced coronal-plane knee deformities can cause deviation of the mechanical axis, which results in asymmetric loading and increased bending forces in fractures of the distal femur metaphysis. This predisposes patients to nonunions or loss of fixation. Concurrent TKA during revision osteosynthesis might facilitate fracture healing, owing to its ability to correct coronal alignment, thereby restoring normal loading patterns at the fracture site, but to our knowledge, this has not been studied. Questions/purposes (1) Does TKA with concurrent revision internal fixation achieve fracture union in patients with coronal-plane deformity from knee arthritis and nonunion or loss of fixation in distal metaphyseal femoral fractures? (2) What is the survivorship and what are the short-term functional outcomes after these reconstructions? (3) What complications occur after these reconstructions? Methods Between 2015 and 2018, one surgeon treated 16 patients with a distal metaphyseal femur fracture nonunion and/or loss of fixation using concurrent TKA plus revision internal fixation. Autologous iliac crest bone grafting was performed in five patients with evident gaps at the fracture site. The indications for the procedure included patients older than 55 years of age presenting with a nonunion and/or loss of fixation of a distal metaphyseal femur fracture in the setting of painful Ahlbäck Grade III to V knee arthritis with an associated coronal-plane deformity. All patients meeting these indications were treated with this approach during the study period. Fracture union assessed by radiological bridging of at least three cortices, TKA survival free from revision due to any reason, coronal-plane correction using tibiofemoral angle, and patient mobility status assessed presurgery and at follow-up using the Parker mobility score (scored 0-9 points, with 9 indicating best mobility) were assessed by two surgeons who were not involved in the care of the study patients. Immediate and delayed complications were recorded. Patients were followed for a minimum of 24 months. The median (range) follow-up was 38 months (27 to 52 months). Results All fractures united after concurrent TKA plus revision internal fixation. In all, 14 of 16 fractures healed before 5 months, while the remaining two fractures united by 6 months. Survivorship analysis revealed a TKA component survival of 94% (95% CI 63% to 99%) at 52 months. The median (range) preoperative Parker mobility score of 5 points (3 to 8) improved to 7 points (2 to 9) at 12 months postoperatively and was maintained at last follow-up (p = 0.001). Four patients experienced complications; these were (1) prolonged surgical wound drainage resulting in debridement and polyethylene liner exchange, (2) deep knee infection needing a staged revision, (3) popliteal vein thrombosis, and (4) prolonged graft site pain. Conclusion Concurrent TKA plus revision internal fixation is effective for achieving union in patients with distal metaphyseal femur nonunion and loss of fixation in the setting of coronal-plane deformity induced by knee arthritis. Short-term TKA survival and improvement in patient mobility are excellent, although 4 of 16 patients in this report experienced complications, as one might expect with a procedure of this magnitude. Based on our results, correction of arthritis-induced coronal-plane knee malalignment can be considered part of the surgical strategy when treating such distal metaphyseal femur nonunions. Better preoperative evaluation of the deformity and control-based comparative studies can further validate the utility of this technique. Level of Evidence Level II, therapeutic study.

What Is the Likelihood of Union and Frequency of Complications After Parallel Plating and Supplemental Bone Grafting for Resistant Distal Femoral Nonunions?

“…Although laterally based locked distal femoral plates have been the mainstay for the initial treatment of these fractures, the mechanical limitations of a laterally positioned locked plate to sustain and neutralize varus bending forces on the medial side during fracture healing can lead to premature collapse or nonunion [9]. Such nonunions can become resistant over time, despite repeated surgical attempts if risk factors such as medial comminution, osteoporosis, tobacco use, obesity, and varus knee alignment are overlooked [11,26]. These resistant nonunions are often complicated by bone defects, coronal and sagittal deformities, and loss of femoral length, resulting in the need for better surgical strategies and implant constructs to achieve healing and improve limb function [3,10,31].…”

CORR Insights®: What Is the Likelihood of Union After Coronal Limb Realignment Using Revision Osteosynthesis and Concurrent TKA in Patients with Advanced Arthritis and Loss of Fixation After Distal Metaphyseal Femur Fractures?

“…Given the low incidence of distal femoral nonunions in association with knee arthritis, it is unlikely that a randomized trial will be performed on patients with this diagnosis. Instead, large trauma institutions should take the examples of Gardner et al [6], Gavaskar et al [7], and Rajasekaran et al [11] to develop consistent treatment algorithms and follow the patients longitudinally. We can then rely on well-reported case series of that design to deliver good data using validated outcome measures, which can be pooled in subsequent systematic reviews.…”

“…The second is addressed by working to create the best possible mechanical and biologic environments necessary for fracture healing. The concept behind the study presented by Gavaskar et al [7] is that by addressing the knee arthritis deformity at the same time as the nonunion, they would create a better mechanical environment for fracture healing. They were able to obtain reliable union with their approach but admit that they did not have a control group or prior clinical or biomechanical studies to provide comparison.…”

“…In the current study [7], the authors prospectively treated 16 patients with the combination of distal femoral nonunion and knee arthritis resulting in coronal malalignment. They achieved a 100% union rate by removing the prior femoral fixation and performing a standard total knee arthroplasty combined with a long retrograde IM nail, along with bone grafting to the fracture site.…”

Radiographic findings involved in knee osteoarthritis progression are associated with pain symptom frequency and baseline disease severity: a population-level analysis using deep learning

“…Assessment of full‐length lower extremity radiographs is essential to understand the magnitude and orientation of coronal plane deviations and the anatomic drivers of limb‐length discrepancies (LLD) when present. This may further guide treatment approach by understanding what procedure may be needed to address the etiology and where to make a correction to restore length, rotation, and alignment of the if surgical intervention is indicated [4, 11, 25]. In the case of arthroplasty, a thorough assessment of these factors may influence component selection and soft tissue balancing [10, 12, 16, 23].…”