Introduction
As discussed in Chapter 5 , the surgical management of tibial plateau fractures relies primarily on open reduction and internal fixation (ORIF) using various fracture fixation principles. Reconstruction, however, does serve an important role in select cases in the acute fracture setting. Additionally, arthroplasty is the primary surgical treatment for addressing posttraumatic end-stage arthrosis after tibial plateau fractures. Unicompartmental and total knee arthroplasty (TKA) for treatment after tibial plateau fractures are not without challenges and postoperative complications. Preoperative and intraoperative planning are crucial for successful outcomes when addressing these challenging surgical cases.
Primary Total Knee Arthroplasty
Rationale for Primary TKA
ORIF of the tibial plateau is the mainstay of treatment in most operative cases of tibial plateau fractures. The goal of periarticular fracture fixation is to restore joint congruity and limb alignment using a stable fixation construct. Unfortunately, not all patients are ideal candidates for ORIF due to the presence of a complex fracture pattern and compromised healing related to their soft tissue and bone biology. Olderly patients with osteoporotic bone who suffer tibial plateau fractures can be considered potential candidates for an acute primary TKA as a definitive form of treatment for their injury.
Complications after ORIF of tibial plateau fractures have been shown to be higher in patients older than 60 years old. When considering ORIF in this patient population, the surgeon should be aware of the most common complications, including fixation failure, posttraumatic arthritis, nonunion, malunion, and medical complications related to a prolonged period of immobilization. In this patient population, the higher complication rate is believed to be due to more significant metaphyseal comminution, poor bone quality, and compromised soft-tissue envelope around the knee. In one retrospective study, a 79% fixation failure rate was documented in patients older than 60 compared with only 7% in younger patients. Additionally, the elderly have been shown to have a more difficult time adhering to weight-bearing precautions, which are crucial for success in the early weeks following ORIF. Poor compliance with weight-bearing restrictions has been shown to be an independent risk factor for fixation failure.
Indications and Benefits of Performing a Primary TKA
Primary TKA for a tibial plateau fracture has few indications and should only be undertaken in a specific patient population. Considering the complications associated with ORIF in this population, the elderly patient with preexisting knee osteoarthritis who is found to have a complex periarticular tibial plateau fracture in the setting of osteoporotic bone could be a candidate for definitive treatment with a primary TKA. Reconstruction with a TKA in this patient population treats both the fracture and concomitant knee osteoarthritis. The clinical finding of preexisting and symptomatic knee osteoarthritis is important in these patients as the absence of arthritis would favor a trial of nonoperative management versus ORIF. If the patient subsequently developed knee osteoarthritis, a TKA could then be considered at a later date.
Elderly patients with these fractures can often have medical comorbidities that would likely be exacerbated by prolonged immobilization after ORIF or can lead to the development of decubitus complications (e.g., pneumonia, deep vein thrombosis, decubitus ulcers). A clear benefit of performing a primary TKA is the ability to allow for immediate full weight bearing and knee range of motion without bracing. Similarly, select elderly polytrauma patients with other injuries that would preclude them from early mobilization (e.g., a contralateral lower limb fracture or an upper extremity fracture making use of assistive devices difficult) can also be considered for primary TKA.
Postoperative Outcomes Following Primary TKA
Postoperative outcomes after primary TKA for tibial plateau fractures are favorable in regard to functional scores. A recent systematic review of all studies performing primary TKA for tibial plateau fractures revealed excellent Knee Society Knee Scores and fair Knee Society Function Scores. , On average, in this systematic review, postoperative knee range of motion at midterm follow-up was found to be 108 ± 10 degrees. To date, there are no studies that directly compare outcomes of primary TKA versus ORIF for the treatment of tibial plateau fractures. Malviya et al. reported patient satisfaction of 90% and noted that 81% of patients returned to their premorbid functional status after primary TKA in their retrospective series of elderly patients. On average, these patients returned to ambulation without use of assistive devices by postoperative day 24.
In the literature, the complication rate averages 15% (range 0%–50%) in these primarily small and retrospective studies. In the largest case series in the literature (n = 30), a reoperation rate of 23% was described. Complications requiring reoperation included: wound complications, periprosthetic fracture, deep infection, removal of loose cement, and revision for aseptic loosening. At midterm follow-up, mortality rates averaged 4.8%.
These results suggest that primary TKA is a valid option for a select group of elderly patients with tibial plateau fractures. Patient selection is important, given the potential complications that this surgery holds. Additionally, it is recommended that a surgeon comfortable with revision arthroplasty techniques performs the reconstruction, given the complexity of the case, which is more similar to revision arthroplasty than a standard TKA for atraumatic osteoarthritis.
Surgical Approach and Decision-Making
As with any complex surgery, preoperative workup and planning are essential for a successful outcome. Examination of the affected extremity should be evaluated for skin and soft-tissue compromise, particularly in an elderly population that is more likely to have a friable soft-tissue envelope following acute trauma. Surgical timing depends on the soft-tissue envelope, but a significant delay is not required. In one study, TKA was performed within an average of 4 days from injury; only one postoperative wound complication was noted. A thorough preoperative medical evaluation must be undertaken to ensure that the patient is optimized to undergo a complex arthroplasty procedure.
Preoperative imaging should include plain radiographs and computed tomography (CT) of the injured knee for fracture pattern identification. Plain radiographs of the ipsilateral tibia and femur should be obtained to rule out any extraarticular deformity, as well as any proximal or distal hardware as the final arthroplasty components often require long stems. Consider obtaining plain radiographs of the contralateral knee to assist with preoperative templating.
Implant choice should be carefully considered well in advance of the operation. Generally, an implant system that creates a balanced knee restores the joint line, and provides knee stability with the least constraint possible should be selected, given concern for earlier aseptic failures with a higher level of constraint. Given that ligamentous injury has been reported to be as high as 71% after tibial plateau fractures, implants with various levels of constraint ought to be made available in the event of compromised collateral ligaments. Similarly, bone loss in these osteoporotic patients can create instability requiring a higher level of constraint such as a condylar constrained implant or even a rotating hinge implant for more significant bony defects. Restoration of bone defects with the use of cement, bone graft, tibial sleeves, or cones must be anticipated. A modular system with stemmed implants should be available as fractures that extend from the plateau into the metaphysis or diaphysis should be bypassed by at least two cortical diameters. Stems also offer the advantage of dispersed stress across the fractured tibia and should be considered with the use of more constrained implants. Additionally, fracture fragment trays, locking plates, and cerclage wires should be available to recreate a stable bony platform prior to the placement of arthroplasty components.
A standard midline incision is recommended. A medial parapatellar arthrotomy is generally sufficient for visualization; however, extensile exposures may be required. Hsu et al. recommend the following systematic approach when performing primary TKA for treatment of periarticular fractures around the knee. First, they recommend preventing fracture propagation using cerclage wires around any fractures that extend into the metadiaphyseal region. Cerclage wires will facilitate the use of intramedullary guides to minimize the risk of fracture propagation or displacement. Next, any fractures of the medial and lateral plateaus are reduced and temporarily fixed with K-wires. Standard fracture fixation principles are followed with the use of plates and/or screws to reconstruct the normal plateau anatomy or to unite any metadiaphyseal fracture fragments.
Following fracture stabilization, attention is turned to reconstruction of the tibial platform. Intramedullary guides are used to make a bone preserving proximal tibia cut. Any bone defects are noted and fill of contained or uncontained defects can be planned with the above-mentioned techniques. If a tibial stem is required, intramedullary preparation is performed. Attention can then be turned to femoral preparation. According to standard knee arthroplasty principles, care must be taken to recreate the joint line and posterior condylar offset in order to optimize knee kinematics.
At this point, the level of implant constraint is selected based on the integrity of the collateral ligaments and the bony architecture. Our most commonly employed implant in this patient population is a semi-constrained knee with stems that bypass the fracture site. However, there is no consensus in the literature regarding the level of constraint required for these cases; these case series with favorable outcomes range from the use of posterior stabilized implants up to rotating hinge systems. Following the placement of trial components, knee kinematics are assessed, and joint stability is verified prior to final component placement. Standard cement techniques are used for implant placement. With a stable construct and well-stabilized knee, the patient is allowed to bear weight as tolerated and fully range the knee without use of a brace.
Posttraumatic Total Knee Arthroplasty
Indications for Posttraumatic TKA
Posttraumatic arthritis is a debilitating complication that can develop after tibial plateau fractures. As discussed in Chapter 8 , this complication occurs and appears to be related to the severity of the trauma, articular malalignment, and older patient age. Treatment for posttraumatic arthritis begins with nonoperative management. Once the patient has failed conservative treatment, reconstruction should be considered. A TKA is indicated in patients with symptomatic tricompartmental arthritis and can also be considered in cases of end-stage arthritis involving one or two compartments of the knee ( Fig. 9.1 ). Although there are no strict age cut-offs, this procedure is generally reserved for adult patients older than 50, given that patients younger than 50 undergoing TKA are at higher risk for revision. However, any adult patient in whom nonoperative management has failed and who shows signs of end-stage arthritis can be considered for knee arthroplasty. In the literature, the average age at the time of TKA due to posttraumatic arthritis after tibial plateau fractures ranged from 56 to 65 years old.
Another potential indication for TKA after tibial plateau fractures is in cases of nonunion. Although rare, nonunion after tibial plateau fractures can occur and does so more frequently in elderly patients or in cases of ORIF complicated by infection. In cases of tibial plateau nonunion, treatment strategies include revision ORIF with bone grafting versus reconstruction with bulk allograft. For elderly patients, especially in the setting of preexisting osteoarthritis, TKA for treatment of the nonunion should be considered. ,
Outcomes of TKA for Posttraumatic Arthritis
The prevalence of posttraumatic arthritis varies between 21% and 44% after tibial plateau fractures. The rate of patients undergoing TKA for management of posttraumatic arthritis, however, is much lower and ranges between 3% and 7.3% in the literature. As expected, with increasing time from injury, the rates of TKA conversion increase. When compared to age-matched controls without a history of plateau fracture, at 2, 5, and 10 years after ORIF, the percentage of patients undergoing TKA are 0.32% versus 0.29%, 5.3% versus 0.82%, and 7.3% versus 1.8%, respectively. Overall, patients with a history of tibial plateau ORIF are 5.3 times more likely to undergo TKA than age-matched patients without a history of tibial plateau fracture. Factors that influence the risk of needing a TKA are patient age, female sex, presence of medical comorbidities, and bicondylar plateau fractures.
Earlier studies showed that TKA for posttraumatic arthritis resulted in lower functional scores when compared to TKA for primary knee osteoarthritis. However, more recent studies have shown that postoperative knee function scores and patient-reported outcomes are comparable to patients undergoing TKA for primary osteoarthritis. , TKA after tibial plateau fractures has been shown to significantly improve knee function and decrease knee pain. , Posttraumatic knee stiffness can be a debilitating complication for patients after sustaining tibial plateau fractures. Following TKA, knee range of motion has been shown to increase 4 to 18 degrees compared to preoperative range of motion. . , , At midterm follow-up, most patients are satisfied after undergoing TKA for posttraumatic arthritis; there was no significant difference in patient satisfaction compared to an age-matched cohort of patients undergoing TKA for primary osteoarthritis.
Implant survivability following TKA for posttraumatic arthritis has also shown to be favorable at mid- and long-term follow-up. , , Complications are not insignificant in this patient population, but revisions for mechanical complications are not significantly different when compared to a control group undergoing TKA for primary osteoarthritis. , Implant survival free of revision due to aseptic loosening is as high as 96% at 15-year follow-up, a number comparable to revision rates of TKA for primary osteoarthritis.
Surgical Challenges and Complications
Although TKA for posttraumatic arthritis after tibial plateau fracture is a useful surgical option, it is not without its challenges and complications. When compared with TKA for primary osteoarthritis, TKA after tibial plateau fractures is associated with significantly higher rates of intraoperative and postoperative complications. , , , The higher rate of intra- and postoperative complications is likely related to posttraumatic stiffness, previous incisions that may have compromised the soft-tissue envelope, malalignment, ligamentous instability, presence of retained hardware, possible occult infection, and bony defects.
Intraoperative complications can include fractures, damage to the extensor mechanism, and collateral ligament injury. , , , These intraoperative complications are likely higher as a result of difficulty with obtaining adequate visualization. Posttraumatic changes after fracture and/or ORIF can make the knee very stiff, which can impede intraoperative visualization similar to that of a revision TKA procedure. In certain cases, one may require the use of a more extensile exposure such as the quadriceps snip, VY turndown, or a tibial tubercle osteotomy. Additionally, extensive soft-tissue releases off the femoral condyles can substantially improve visualization and help protect the extensor mechanism. If such releases are anticipated or planned, a constrained or hinged implant option should be available.
Postoperative complications occur at higher rates compared with TKA for primary osteoarthritis, particularly within the first 2 years after surgery. , At 15-year follow-up, one recent study showed that complications occurred at a rate as high as 34%, with 90% of these complications occurring within the first 2 years after TKA. One of the most common postoperative complications has been shown to be early wound complications, likely due to compromised soft-tissue envelope in the setting of previous surgical incisions, retained hardware, and posttraumatic changes after a fracture. , , Other notable complications can include arthrofibrosis, infection, extensor mechanism injury, aseptic loosening, patellar subluxation, and periprosthetic fracture. ,
Preoperative Workup and Planning
In order to optimize the patient’s outcome intraoperatively and postoperatively, a thorough preoperative examination and surgical plan are required. The surgeon should approach the preoperative workup in a manner similar to that of a complex revision arthroplasty case. Starting with the physical examination, the skin and soft tissues must be inspected. As mentioned, the wound complication rates after TKA for posttraumatic arthritis are much higher than in primary TKA cases. , , The surgical scars and the location of any prior grafts or flaps should be noted and documented to plan out the surgical approach. For the patient with multiple revisions, skin may be thin and significantly adherent to the proximal tibia, patella, or femur. A plastic surgery consultation should be considered if there is concern about postoperative wound closure that may require skin grafting or flap coverage.
Knee range of motion should be assessed preoperatively. It is well documented that knee stiffness is a common complication after tibial plateau fractures following operative or nonoperative treatment. , , One-third of patients treated with ORIF for their tibial plateau fractures underwent conversion to TKA due to pain and stiffness. Identification of knee contractures is useful to help plan for necessary releases intraoperatively. Although TKA for posttraumatic arthritis has been shown to increase knee range of motion by 4 to 18 degrees, expectations of postoperative knee range of motion should be discussed with the patient as it has been shown that preoperative knee range of motion is one of the biggest determinants of postoperative knee range of motion. , , ,
A thorough ligamentous examination should be performed, given the high rate of ligamentous injury following tibial plateau fractures. Identification of incompetent collateral ligaments will help guide decision-making regarding the level of implant constraint. We recommend the use of an implant system that creates a balanced knee, restores the joint line, and provides knee stability with the least constraint possible ( Fig. 9.2 ). Even in patients without evidence of preoperative ligament insufficiency or significant bone loss on imaging, revision TKA implant systems need to be available on the day of surgery in anticipation of potential intraoperative complications such as collateral ligament injury or bone defects.
Preoperative imaging should include plain radiographs of the knee and weight-bearing hip-to-ankle radiographs to assess leg alignment and presence of hardware and to evaluate for extraarticular deformity, which could complicate component positioning or the use of long-stemmed implants. The use of intraoperative computer navigation can be helpful in cases with hardware or extraarticular deformity of the tibia or femur. CT of the knee is not required but can be useful to rule out nonunion or osseous defects that are not readily appreciated on plain radiographs.
Infection is a significant complication in this patient population and has occurred at a rate of 3.2% to 20% in the literature, which is higher than that of TKA for treatment of primary osteoarthritis. , For this reason, a thorough preoperative history and workup should be undertaken. Red flags include any history of wound complication, failure of fixation, nonunion, multiple surgeries, or a history of an open tibial plateau fracture. In addition to complete blood count, consider obtaining a C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) prior to surgery. Aspiration and synovial fluid analysis with culture should be performed in patients who have had a history of previous wound healing problems, tibial nonunion, or elevated inflammatory markers.
The presence of hardware around the joint may complicate the surgical approach and will most often require hardware removal. Preoperative planning should include the decision to perform either a one- or two-stage conversion from ORIF to TKA. In most cases in the literature, conversion to TKA was performed in a single-stage fashion. , There is some evidence that the history of ORIF around the knee and the presence of retained hardware following TKA may increase the risk of infection postoperatively. More recent studies have shown a trend toward higher infection rates for one- or two-stage procedures and a trend toward more mechanical complications for cases where previous hardware is fully or partially retained after TKA, but these results did not reach statistical significance. , The decision to remove the hardware in a staged fashion should be made, in part, based on any history of past infection, signs or symptoms of current infection, and with the patient’s skin and soft-tissue envelope in mind.
Surgical Approach and Decision-Making
As discussed, the posttraumatic knee can be difficult to expose safely, and precautions must be taken to reduce the risk of wound complications. For patients without previous knee surgery, a standard midline incision is recommended. If previous incisions have been made, the most recent incision should be used as long as it can be modified to provide adequate exposure. Using the most lateral incision is recommended as this will avoid interrupting the blood supply to the lateral flap that obtains its most robust dermal blood supply from the medial aspect of the knee. , If transverse scars are present, they can be most safely crossed at a 90-degree angle. Caution should be taken when raising flaps in order to preserve the blood supply as best as possible.
A medial parapatellar arthrotomy is our standard approach to the joint. Cultures of the synovial fluid can be taken, especially in patients treated with previous tibial plateau ORIF. Extensive release of scar within the gutters, suprapatellar pouch, and the peritendinous tissues may be required to sublux the patella for adequate visualization. The use of more extensile exposures such as the quadriceps snip, femoral epicondylar peel, or a tibial tubercle osteotomy may be required in order to prevent iatrogenic injury to the extensor mechanism.
Following adequate releases to obtain sufficient visualization, the knee can be prepared for arthroplasty components. As in primary TKA, the goal in this setting is to provide a stable knee that restores neutral mechanical alignment and sagittal and coronal balance, preserves the joint line and posterior tibial slope, and obtains normal patellar tracking. Posttraumatic malunion, nonunion, bone defects, extraarticular deformity, and ligament deficiency will make this a challenge.
A subperiosteal release of the proximal tibia soft tissue is performed to expose the medial plateau. Any bony defects and the extent of articular malalignment are assessed. We utilize intramedullary guides for tibial preparation, but extramedullary guides or navigation may be required in cases with intramedullary hardware or significant extraarticular deformity. Preoperative templating can assist with planned bone cuts to restore mechanical alignment. If proximal tibial hardware is located within the planned cut, the hardware will need to be fully or partially removed. Ideally, this should be done as minimally invasive as possible and is incorporated into the incision. If needed, the proximal aspect of the plate can be cut with a diamond-tipped burr a and the remainder of screws and distal plate can be retained; metal debris must be thoroughly removed ( Fig. 9.3 ).
