846

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Failure of LCP Condylar Plate Fixation in the Distal Part of the Femur. A Report of Six Cases Heather A. Vallier, Theresa A. Hennessey, John K. Sontich and Brendan M. Patterson J Bone Joint Surg Am. 2006;88:846-853. doi:10.2106/JBJS.E.00543

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846 COPYRIGHT © 2006

BY

THE JOURNAL

OF

BONE

AND JOINT

SURGERY, INCORPORATED

Failure of LCP Condylar Plate Fixation in the Distal Part of the Femur A REPORT

OF

SIX CASES

BY HEATHER A. VALLIER, MD, THERESA A. HENNESSEY, MD, JOHN K. SONTICH, MD, AND BRENDAN M. PATTERSON, MD Investigation performed at MetroHealth Medical Center, Cleveland, Ohio

T

he treatment of comminuted, intra-articular distal femoral fractures (Orthopaedic Trauma Association [OTA] classification1 33-C3) is challenging. Many of these injuries are the result of high-energy trauma, which generates severe soft-tissue damage and articular and metaphyseal comminution. Bone loss resulting from open fracture and poor bone quality may decrease the stability of fixation. Traditional devices for internal fixation have included the 95° condylar blade-plate, the dynamic condylar screw with a 95° side-plate, and intramedullary nails. However, coronal fractures or extensive distal comminution may preclude the use of these devices. In such cases, a lateral buttress or neutralization plate may be used. The condylar buttress plate was the first implant designed to serve this function. Unfortunately, when this device is applied in the presence of medial comminution or bone loss, failure of fixation and varus collapse may eventually result2,3. Recent advances in technology for the treatment of distal femoral fractures include the Less Invasive Stabilization System (LISS; Synthes, Paoli, Pennsylvania) and the Locking Compression Plate (LCP) condylar plate (Synthes)4-15. Each of these implants offers multiple points of fixed-angle contact between the plate and screws in the distal part of the femur, theoretically reducing the tendency for varus collapse that is seen with traditional lateral plates. The LISS differs from the LCP condylar plate in composition, shape, and placement. Early clinical studies of the LISS have demonstrated a high frequency of fracture union with low rates of malalignment7-9,15. Few cases of failure of the LISS have been reported11,12,16. To our knowledge, there have been no published studies focusing specifically on the LCP condylar plate and no reported cases of failure of this implant in the distal part of the femur. The purposes of this report were to describe and critically examine six cases of failure of the LCP condylar plate and to discuss the limitations of this implant for the treatment of distal femoral fractures. The patients were informed that data concerning the cases would be submitted for publication. Materials and Methods e retrospectively reviewed the cases of all forty-six patients who had been treated primarily with the LCP

W

condylar plate for a distal femoral fracture during a thirty-sixmonth period at our hospital, and we identified six implant failures. Fracture care was provided by fellowship-trained traumatologists at a level-I trauma center. Information on these patients can be found in Table I and the Appendix. Indications for the use of this implant included a coronal plane fracture, osteopenia, and/or extensive distal fracture comminution precluding insertion of a conventional 95° condylar blade-plate or a dynamic condylar screw. All forty-six patients underwent assessment and resuscitation according to Advanced Trauma Life Support (ATLS) guidelines17. Open wounds were inspected, and dressings were applied. Intravenous antibiotics and tetanus prophylaxis were administered. Closed reductions were performed, and splints were applied. Open fractures were managed with urgent déTABLE I Information on Patients Treated with the LCP Condylar Plate at Our Hospital Implant Failure

All Cases

62.2 (range, 36-88)

60.0 (range, 21-88)

Men

2

19

Women

4

27

Automobile acc. Motorcycle acc.

4 1

26 11

High-energy fall Low-energy fall

1 0

5 3

Mean age (yr)

Mechanism of injury

0

1

Open fracture

Crush

4

25

Closed fracture

2

21

33-A3 33-C1

0 0

5 5

33-C2 33-C3

0 6

9 27

OTA classification*

*OTA = Orthopaedic Trauma Association.

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bridement and irrigation. At the surgeons’ discretion, open fractures were either treated primarily with open reduction and internal fixation or managed with provisional external fixation. Provisional external fixation was converted to internal fixation after repeat débridement and irrigation within twenty-four to forty-eight hours. Definitive treatment consisted of fixation with the LCP condylar plate. A lateral approach was used in all patients. The articular surface was visualized, and open reduction and internal fixation of the articular surface was performed. The articular segment was stabilized to the femoral shaft with the LCP condylar plate. Indirect reduction principles were followed. A minimum of four locked screws were placed distally. A minimum of seven cortices of fixation were obtained proximally. Standard large-fragment cortical screws were used to stabilize the plate to the femoral shaft. Range of motion of the knee was permitted when adequate soft-tissue healing had occurred. The patients were instructed to remain non-weight-bearing for at least twelve weeks postoperatively. Results deep infection developed postoperatively in one patient. She was treated with serial débridement and irrigation, hardware removal, and intravenous antibiotics. After fourteen months, she had a nonunion without recurrence of the infection. Additional surgery was not planned because of medical comorbidities and functional decline. Three closed fractures were treated with morsellized allograft bone during the index procedure. Six patients with an open fracture underwent autogenous iliac crest bone-grafting between six and ten weeks after fixation. After a minimum of twelve months of follow-up, thirty-nine patients had fracture union. The fixation failed in six patients. The initial fracture alignment, assessed on plain anteroposterior and lateral radiographs, was acceptable in all six patients.

A

Case Reports ASE 1. A fifty-four-year-old man was struck by a bus while riding a motorcycle. His injuries included an APC (anteroposterior compression) type-III18 pelvic ring disruption, a type-IIIA19,20 open right distal femoral fracture (OTA 33-C3), and a right ulnar fracture. The patient was hypotensive on arrival at the hospital and was immediately taken to the operating room, where he underwent internal fixation of the pelvis, exploratory laparotomy, and débridement and irrigation and spanning external fixation of the open femoral fracture. Approximately thirty-six hours later, he underwent definitive fixation of the right distal femoral fracture with an LCP condylar plate. The wounds healed uneventfully, and knee motion returned to nearly normal by six months, at which time he reported mild pain in the stance phase of gait. At nine months, he presented with increased pain and deformity. Radiographs demonstrated a femoral nonunion, varus collapse, and implant failure. He was treated with a 95° condylar blade-plate and application of iliac crest bone graft and allograft. Inspection of the removed hardware showed a fracture

C

Fig. 1-A

Figs. 1-A through 1-D Case 2. Fig. 1-A Anteroposterior radiograph made after the initial fixation and placement of provisional antibiotic-impregnated polymethylmethacrylate beads.

of one of the locking screws at the screw-plate interface and impending fatigue failure of the plate. The nonunion healed after four months. At twenty-one months, the patient had no knee pain and could flex the knee from 0° to 115°. CASE 2. A thirty-six-year-old, otherwise healthy man was involved in a high-speed motor-vehicle accident. On the right side, he sustained a fracture of the femoral shaft, a typeIIIA19,20 open fracture of the patella, a type-IIIA open fracture of the tibial plateau, a fracture-dislocation of the calcaneus, and fractures of the radial and ulnar shafts with compartmental syndrome. On the left, there was a type-IIIA open Monteggia fracture-dislocation and a type-IIIA open distal femoral

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Fig. 1-B

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Fig. 1-C

Figs. 1-B and 1-C Anteroposterior and lateral radiographs demonstrating the broken plate and medial collapse at the fracture site.

fracture with extensive comminution and articular fractures in both the sagittal and the coronal plane (OTA 33-C3). On the day of injury, the patient underwent débridement and irrigation of all of the open fractures and definitive fixation of the upper extremities as well as the right femur, patella, and tibia. He also underwent provisional spanning external fixation of the left femoral fracture. After forty-eight hours, he was returned to the operating room for repeat débridement and irrigation as well as open reduction and internal fixation of the distal part of the left femur with an LCP condylar plate. Antibiotic polymethylmethacrylate beads were placed into a massive metaphyseal defect (Fig. 1-A). Range-ofmotion exercise of the left knee was initiated three days after the surgery. Seven weeks after the surgery, autogenous iliac

crest and morsellized allograft croutons were applied at the site of the distal femoral fracture. Cultures of intraoperative specimens were negative, and all of the hardware appeared to be stable. Four months after the injury, the patient had 115° of flexion of the left knee and he was taking no pain medications. At that time, he began progressive weight-bearing. He returned to working on his farm. Fourteen months after the injury, the patient noted the sudden onset of severe pain and deformity in the left thigh while he was walking in his barn. Radiographs demonstrated a nonunion with failure of the plate in the distal femoral metaphysis (Figs. 1-B and 1-C). He underwent a revision open reduction and internal fixation with a 95° condylar blade-plate, and augmentation with iliac crest and allogenic bone graft.

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The postoperative course was unremarkable. Bilateral range-of-motion exercise of the knee was permitted three days after the surgery. Three months after the surgery, plain radiographs demonstrated some healing bilaterally, and she was allowed to start walking. Six months after the surgery, at the time of routine follow-up, she reported no symptoms but plain radiographs demonstrated 5° of varus deformity of the distal part of the right femur with further evidence of metaphyseal healing. A broken screw was noted at the distal screwplate interface. The findings were reviewed with the patient, and activity as tolerated was permitted. She returned three months later, at which time she had no clinical symptoms. Radiographs made at that time suggested that both distal femoral fractures were united, with 10° of varus collapse on the right. She was able to walk outside of her home with the assistance of a cane fifteen months after surgery.

Fig. 1-D

Anteroposterior radiograph made after the revision open reduction and internal fixation with a 95° condylar blade-plate.

There was no evidence of infection. Eighteen months postoperatively, the fracture appeared healed radiographically, the patient reported no pain, and there was 115° of knee flexion (Fig. 1-D). The patient returned to work on his farm. CASE 3. An eighty-eight-year-old woman was involved in a high-speed motor-vehicle accident in which she sustained a bilateral closed distal femoral fracture (OTA 33-C3). Before the injury, she was capable of independent community ambulation, and she had a history of obesity and type-II diabetes mellitus. On the day of the injury, she underwent open reduction and internal fixation with an LCP condylar plate and allogenic bone-grafting for both fractures.

CASE 4. A sixty-two-year-old woman sustained an isolated type-IIIA19,20 open distal femoral fracture (OTA 33-C3) in a high-speed motor-vehicle accident. She had a history of obesity and type-II diabetes mellitus. She underwent débridement and irrigation and provisional spanning external fixation of the fracture on the day of the injury. After forty-eight hours, repeat débridement and irrigation as well as open reduction and internal fixation were performed. An LCP condylar plate was used because of medial and lateral coronal plane fractures. Knee motion was permitted two days after the surgery, and the early postoperative course was without complications. Twelve weeks after the surgery, some fracture-healing was noted on plain radiographs and progressive partial weight-bearing was begun. Eighteen weeks after the surgery, the patient returned to the clinic and reported mild knee stiffness and swelling with occasional pain that did not require medication. Plain radiographs made at that time demonstrated breakage of two locked screws at the screw-plate interface and lateral displacement of another screw. Sixteen months after the surgery, the fracture appeared united with a loss of 5° of angular alignment, and the patient could flex the knee from 0° to 100°. Because some of the distal screws were prominent, the patient was considering elective hardware removal at the time of writing. CASE 5. A seventy-eight-year-old woman sustained a typeIIIA19,20 open fracture of the distal part of the femur with coronal and sagittal fractures of the articular surface (OTA 33-C3) in a high-speed motor-vehicle accident. She underwent débridement and irrigation as well as open reduction and internal fixation of the fracture with an LCP condylar plate. She did not have any problems with wound or soft-tissue healing. Rangeof-motion exercise of the knee was initiated three days postoperatively. No weight-bearing was permitted for twelve weeks. Radiographs made at twelve weeks demonstrated some healing of the distal femoral fractures with stable alignment, and the patient began progressive weight-bearing. Six months postoperatively, the patient returned to the clinic. She reported mild pain and stiffness in the knee that

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Fig. 2-A

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Fig. 2-B

Figs. 2-A through 2-D Case 6. Figs. 2-A and 2-B Anteroposterior and lateral radiographs made twelve weeks after fixation, demonstrating loosening of one distal screw.

did not require medication. Radiographs showed two screws that were broken at the distal screw-plate interface and 5° of varus collapse. Abundant medial metaphyseal callus was present at that time. The patient subsequently had a decrease in the pain over the following ten months with additional healing of the fracture and no further malalignment. At the time of final follow-up, she was using a cane for walking outside of her home and knee flexion was from 0° to 100°. CASE 6. A fifty-five-year-old woman with long-standing type-I diabetes mellitus and tobacco use fell down stairs, sustaining a comminuted distal femoral fracture (OTA 33-C3). On the day of the injury, she underwent open reduction and internal fixation with an LCP condylar plate. No wound complications were noted. She was instructed to remain non-weight-bearing for twelve weeks. At twelve weeks, radiographs demonstrated stable alignment of the fracture and the implant with the exception of loosening of one distal screw (Figs. 2-A and 2-B). Some early fracture-healing was evident, so progressive weight-bearing was started. The patient returned seven months postoperatively, at which time she was experiencing mild activity-related

pain and swelling in the knee. Radiographs showed two screws that were broken at the distal screw-plate interface and four distal screws backing out of the distal part of the femur with 10° of varus collapse (Fig. 2-C). Revision open reduction and internal fixation was performed. The malunion was corrected, and the bone was stabilized with use of a 95° condylar bladeplate, iliac crest bone graft, and morsellized allograft bone (Fig. 2-D). Twenty months later, the fracture was healed, function had improved, and knee flexion was from 0° to 110°. Discussion igh-energy distal femoral fractures are frequently associated with articular and metaphyseal comminution. Coronal plane fractures and extensive distal comminution generally preclude the use of traditional fixed-angle devices or retrograde nails. Fixation of these fractures with a lateral plate alone has historically been associated with nonunion and/or malunion with varus collapse. Prior to the advent of locked plates, this problem may have been addressed with dual medial and lateral fixation, causing additional surgical insult to the local fracture biology21,22. Reports have also described adjunctive medial external fixation, or medial endosteal substitution with the use of in-

H

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cluded technical errors in plate placement and early weightbearing in the presence of delayed fracture union. The LISS differs from the LCP condylar plate in composition, shape, and placement. The LISS actually functions as an internal fixator with locked unicortical fixation in the femoral shaft. LCP implants may include locked screws or conventional screws proximally. It has been our practice to use bicortical, nonlocked screws in the proximal portion of the LCP condylar plate, which may improve pull-out strength compared with that provided by the unicortical locked screws of the LISS. Of the forty-six LCP condylar plates that were used in the distal part of the femur at our institution over a thirty-sixmonth period, and that were followed for a minimum of twelve months, six (13%) failed. The patients in whom these plates failed had been treated by fellowship-trained traumatologists who had extensive experience with complex distal femoral fractures and with use of the LCP device. Two patients (Cases 1 and 2) had nonunion with plate failure. Both had sustained the initial fractures as a result of high-energy trauma. In the first patient, the fixation failed nine months after the injury and was successfully revised to a blade-plate.

Fig. 2-C

Anteroposterior radiograph showing varus collapse and broken screws at the screw-plate interface.

tramedullary plates, which is technically demanding and may compromise additional reconstructive options2,3. The introduction of plates with the option of locked screws has provided the means to increase the rigidity of fixation in osteoporotic bone or in the presence of periarticular or juxta-articular fractures with a small epiphyseal segment4-6,14. There are many theoretical advantages to using a locked plate in the distal part of the femur. The LCP condylar plate provides multiple points of fixed plate-to-screw contact, generating greater stability than is provided by a single lateral construct, which potentially reduces the tendency for varus collapse. The LISS also allows minimally invasive insertion and preservation of vascularity to the lateral cortex. Early clinical results following use of the LISS in the distal part of the femur have been promising7-9,15, as have been the early results of the use of LCP implants for other fractures13. Kregor et al. reported a 5% prevalence of proximal screw failure or loosening after treatment of 103 distal femoral fractures with the LISS9. Another recent paper described failure of the LISS, with plate breakage or loss of proximal screw fixation, in four patients (18% of their patients) treated for a distal femoral fracture16. Potential reasons for these failures in-

Fig. 2-D

Anteroposterior radiograph made after the revision open reduction and internal fixation with a 95° condylar blade-plate.

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The slow appearance of callus on early postoperative radiographs may have been an indication for bone-grafting after three to six months, and this intervention may have prevented the failure of the implant at nine months. Because function was not limited by pain, a less aggressive approach was taken initially. (He was observed—i.e., no surgery was anticipated.) The second patient had implant failure at fourteen months. He had previously undergone bone-grafting of a massive metaphyseal defect and was functioning at a high level. We have encountered another patient with this type of failure. She was initially treated, at an outside hospital, with the same device. The plate was placed posteriorly on the lateral femoral condyle with 2 cm of shortening and malalignment in external rotation, which may have increased the potential for plate breakage. That patient also had a history of diabetes and was of advanced age, which may have decreased the ability of the fracture to heal. The remaining patients (Cases 3 through 6) all had failure at the screw-plate interface with 5° to 10° of medial collapse. All of these patients had metabolic factors that contribute to a diminished healing response, including advanced age, osteoporosis, obesity, diabetes mellitus, or tobacco use. Furthermore, two (Cases 4 and 5) had an open fracture, which may have been associated with greater disruption of the local blood supply at the time of injury. Allograft bone was placed at the time of the initial surgery in one patient (Case 3); however, none of the others underwent primary bone-grafting. It is possible that more judicious use of bone graft or bone-graft substitutes would have enhanced the healing response and decreased the propensity for mechanical failure and varus collapse. Fortunately, only one of these four patients required revision fixation. The other fractures united, and to date the patients have not had pain or functional impairment that was sufficient to warrant additional surgery. To our knowledge, this is the first report of failures of the LCP condylar plate. Previously described failures of LCP plates in other anatomical locations were speculated to be secondary to technical errors, including inappropriate plate length or size, an insufficient number of screws, or the use of unicortical (instead of bicortical) screws23. It is possible that additional fixation in our patients would have decreased the risk of implant failure. Simonian et al. described angled screw placement through the plate from the lateral metaphysis into the medial femoral condyle as an adjunct in the stabilization of distal femoral fractures24. In their model, the addition of a single screw in this location more than doubled the stiffness of the construct under an axial load, reducing the tendency for varus collapse. Three of our patients had screw placement in this location as part of the initial fixation, but failure still occurred. Modification of the design of the LCP condylar plate to permit locked screws to be directed obliquely, from proximal and lateral to distal and medial, could be advantageous. Furthermore, the LCP condylar plate could be modified to eliminate the cannulation of the locked screws. This could reduce the frequency of screw breakage at the screw-plate interface, as solid screws may be less likely to fail over time.

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In all three cases of plate fatigue (Cases 1 and 2 and the patient treated at another hospital), the fracture occurred through the most proximal of the locking holes in the condylar portion of the plate. None of our patients had a screw inserted there. We speculate that increasing the cross-sectional thickness of the plate and/or eliminating the screw hole at that level would improve the fatigue strength of the plate and reduce the frequency of implant failure. Alternatively, routine placement of a screw through that hole could be considered to reduce the mechanical stress in the fixation construct at that level25. We believe that locking plates represent a valuable advancement in fracture treatment. However, the limitations of this new technology and the indications for its use have not been completely elucidated. Despite the introduction of new implants, principles of fracture management remain unchanged. Severe medial comminution necessitates the use of indirect methods of reduction, preservation of biology, and protected weight-bearing. Additionally, we propose that the LCP condylar plate be used only when conventional fixed-angle implants cannot be placed. A recent study demonstrated that the 95° condylar blade-plate has greater stiffness than the LISS under both axial and torsional loading26. Although no biomechanical studies of the LCP condylar plate have been published to our knowledge, each of the failed implants that required a reoperation in our series was successfully revised to a blade-plate. Furthermore, we propose that traditional fixedangle devices may be more cost-effective for most distal femoral fractures. In our hospital, the cost of an eight-hole, 95° condylar blade-plate construct is $370 compared with $743 for a dynamic condylar screw with a 95° side-plate and $2089 for an LCP condylar plate of similar size. In conclusion, the LCP condylar plate represents an evolutionary approach to the surgical management of distal femoral fractures, but it does not completely solve the age-old problems of nonunion and malunion. We encountered six cases of implant failure. Accurate reduction and fixation, judicious use of bone-grafting, and protected weight-bearing, perhaps combined with modifications in implant design, may decrease the prevalence of these problems in the future. Appendix A table showing clinical details of the six cases is available with the electronic versions of this article, on our web site at jbjs.org (go to the article citation and click on “Supplementary Material”) and on our quarterly CD-ROM (call our subscription department, at 781-449-9780, to order the CD-ROM). 

Heather A. Vallier, MD Theresa A. Hennessey, MD John K. Sontich, MD Brendan M. Patterson, MD Department of Orthopaedic Surgery, MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109. E-mail address for H.A. Vallier: [email protected]

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The authors did not receive grants or outside funding in support of their research for or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund,

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foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.

doi:10.2106/JBJS.E.00543

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20. Gustilo RB, Mendoza RM, Williams DN. Problems in the management of type III (severe) open fractures: a new classification of type III open fractures. J Trauma. 1984;24:742-6. 21. Jazrawi LM, Kummer FJ, Simon JA, Bai B, Hunt SA, Egol KA, Koval KJ. New technique for treatment of unstable distal femur fractures by locked doubleplating: case report and biomechanical evaluation. J Trauma. 2000;48:87-92. 22. Sanders R, Swiontkowski M, Rosen H, Helfet D. Double-plating of comminuted, unstable fractures of the distal part of the femur. J Bone Joint Surg Am. 1991;73:341-6. 23. Sommer C, Babst R, Muller M, Hanson B. Locking compression plate loosening and plate breakage: a report of four cases. J Orthop Trauma. 2004;18:571-7. 24. Simonian PT, Thompson GJ, Emley W, Harrington RM, Benirschke SK, Swiontkowski MF. Angulated screw placement in the lateral condylar buttress plate for supracondylar femoral fractures. Injury. 1998;29:101-4. 25. Hipp JA, Hayes WC. Biomechanics of fractures. In: Browner BD, Jupiter JB, Levine AM, Trafton PG, editors. Skeletal trauma: basic science, management, and reconstruction. Philadelphia: Saunders; 2003. p 90-119. 26. Zlowodzki M, Williamson S, Cole PA, Zardiackas LD, Kregor PJ. Biomechanical evaluation of the less invasive stabilization system, angled blade plate, and retrograde intramedullary nail for the internal fixation of distal femur fractures. J Orthop Trauma. 2004;18:494-502.