Nailed Cementoplasty: A Salvage Technique for Rorabeck Type II Periprosthetic Fractures in Octogenarians

The Journal of Arthroplasty Vol. 25 No. 6 2010

Nailed Cementoplasty: A Salvage Technique for Rorabeck Type II Periprosthetic Fractures in Octogenarians Peter Bobak, MD, Ioannis Polyzois, MBchB, MRCS, Simon Graham, MBchB, Zakareya Gamie, BSc, MBchB, and Eleftherios Tsiridis, MD, MSc, PhD, FRCS

Abstract: Periprosthetic femoral fractures around a total knee arthroplasty present a surgical challenge in octogenarians with advanced osteoporosis. We describe a salvage technique combining retrograde intramedullary nailing augmented with polymethylmethacrylate cement in 5 patients followed up for a median time of 12 months. The nail/cement construct bridges the femoral canal tightly and simulates a stemmed cemented revision component. All patients had an uncomplicated recovery and returned to their preinjury functional status within 4 months. This procedure does not disrupt the soft tissue envelope around the fracture site, is easy to perform and permits immediate full range of movement. When standard retrograde nailing or plating alone is inadequate in maintaining severely osteoporotic fracture reduction, nailed cementoplasty is proposed as a salvage procedure in octogenarians unfit for lengthy interventions. Keywords: periprosthetic, fracture, retrograde, intramedullary nail, cement, osteoporosis. © 2010 Elsevier Inc. All rights reserved.

The incidence of periprosthetic femoral fractures around total knee arthroplasties (TKAs) ranges between 0.3% and 2.5% [1]. Supracondylar periprosthetic fractures are defined as those occurring within 15 cm of the joint line or, in the case of a stemmed component, within 5 cm of the proximal end of the implant [1]. There are various predisposing factors including osteoporosis, poor knee flexion and anterior femoral notching, although there is recent evidence to dispute the latter [2]. Rorabeck and Taylor [3] described 3 types of periprosthetic femur fractures. Type I are non-displaced fractures with a stable prosthesis, type II are displaced fractures with a stable prosthesis, and type III are those with an unstable prosthesis. When the prosthesis is unstable, a long-stemmed revision component is necessary for the TKA to function [1,4]. In the case of a displaced fracture with a stable prosthesis, the current methods of treatment include

From the Academic Department of Trauma and Orthopaedic Surgery, Leeds General Infirmary, Leeds Teaching Hospitals NHS Trust, School of Medicine, Leeds University, Great George Street, Leeds, LS1 3EX, UK. Submitted September 15, 2008; accepted June 21, 2009. No benefits of funds were received in support of the study. Reprint requests: Eleftherios Tsiridis, MD, MSc, PhD, FRCS, Academic Department of Trauma and Orthopaedics, Leeds General Infirmary, Leeds Teaching Hospitals NHS Trust, School of Medicine, Leeds University, Great George Street, Leeds, LS1 3EX, UK. © 2010 Elsevier Inc. All rights reserved. 0883-5403/2506-0016$36.00/0 doi:10.1016/j.arth.2009.06.034

internal fixation with conventional or locking plates [1,5,6] and retrograde intramedullary nails [7,8]. Conventional plate fixation in octogenarians with advanced osteoporosis is not always feasible. In addition to disturbing the soft tissue envelope when performed openly, there is insufficient screw purchase due to cortical thinning and lack of normal metaphyseal bone density. Locking plates, which can be inserted through minimally invasive incisions, allow locking of the screws on the plate increasing the points of fixation from 2 (near and far cortex) to 3 (plate, near and far cortex). This provides an advantage over conventional plating for treating osteoporotic fractures, although can be technically demanding. Nailing on the other hand, often fails to maintain fracture reduction in “stovepipe”-like osteoporotic femora due to limited contact surface [5]. We propose a salvage technique that combines cementoplasty with supracondylar nailing to achieve fracture stability and early mobilization for the treatment of Rorabeck type II fractures in octogenarians with advanced osteoporosis and significant co-morbidities unfit for prolonged surgical procedures.

Patients and Methods Demographic and Operative Data Five patients with Rorabeck type II [3] periprosthetic supracondylar knee fractures who had significant comorbidities and were classified as American Society of Anesthesiologists (ASA) 3 [9] were reviewed. All fractures were treated using retrograde supracondylar nails (Synthes, Sheffield, UK) augmented with polymethylmethacrylate (PMMA) cement. All patients were

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Fig. 1. A, Rorabeck type II periprosthetic fracture around a press-fit condylar (PFC) cruciate-retaining prosthesis, demonstrating marked osteoporosis with dilatation of the diaphyseal/ metaphyseal distal femur. The fracture line extends from above the flange of the femoral component to the posterior femoral condyles. The femoral and tibial components are well fixed to the bone. The arrow demonstrates cortical disruption due to a fresh fracture. B, Flexion deformity of the fracture presented in panel A. The femur has got a “stovepipe”-like configuration.

females with a median age of 85 years (range, 82–90). Periprosthetic fractures involved 3 left and 2 right knees all with cruciate-retaining press-fit condylar (PFC) cemented TKAs in situ (Figs. 1A and B, 2A and B). The mechanism of injury was a low-velocity domestic fall in all cases. The median time interval from implantation to fracture was 5 years (range, 3–7 years). A retrograde nail 12 × 160 mm in size (Synthes Sheffield, United Kingdom) was used in all cases. All patients had combined spinal and regional anesthesia, and mean tourniquet time was 42 min (range, 35–55). The mean estimated blood loss was 100 mL (range, 80-150 mL). Patients were followed up at 6 weeks, 3 months, 6 months, and yearly thereafter. The medical notes were reviewed to determine the age, sex, affected side, mechanism of injury, time after the index procedure, type of knee prosthesis in situ, and the length and size of the nail used. Operative records were

Fig. 2. A and B, Anteroposterior and lateral views of the second case demonstrating the fracture line running just above the prosthesis flange to the posterior femoral condyles with valgus displacement. The arrow in panel B indicates the sharp edge of the fresh periprosthetic fracture.

examined to record the type of anesthesia, tourniquet time, and the estimated blood loss. Postoperative Clinical and Radiographic Data Postoperative clinic notes provided information about Rorabeck's criteria [4] of optimal management. These include fracture union, pain-free range of knee movement from 0–90°, less than 2 cm of shortening, less than 5° of varus/valgus, less than 10° deformity in the sagittal plane, and a return to the preinjury level of ambulation.

Nailed Cementoplasty in Periprosthetic Knee Fractures  Bobak et al

Postoperative radiographs were also used to measure the femoral diameter and the ratio of nail length bypassing the proximal fracture line over the ipsilateral femoral diameter at the fracture site [10]. We defined radiological union as cortical continuity on both the anteroposterior and the lateral radiographs with external formation of callus [11]. The Oxford knee [12] and the Euro Quality of Life 5D [13] scores were also recorded.

Operative Technique All patients were positioned supine on a radiolucent operating table. The knee was maintained in flexion using a soft popliteal sterile support and a pneumatic tourniquet was used in all cases. Part of the previous midline approach was used and the knee joint was opened via a mini medial parapatellar arthrotomy. The patella was never completely dislocated but was retracted to the side using a retractor. A 13-mm drill was used to open the femoral notch through which the fracture was disimpacted and aligned using a short metal rod as a lever. The fracture site was not exposed at any stage of the procedure thus maintaining the soft tissue envelope completely intact. The rod was then removed from the distal femur. Fracture reduction and alignment was maintained manually with the help of the soft popliteal support. A cement restrictor was inserted at the adequate predetermined length to allow nail introduction. The canal was prepared using pulse lavage irrigation followed

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by hydrogen peroxide drying. Cement was then delivered early to increase penetration into the cancellous bone in a retrograde fashion. There was no cement pressurization and intermittent use of fluoroscopy reduced the possibility of extrusion at the fracture site and to reduce cardiovascular events. After this, a retrograde supracondylar femoral nail (Synthes, Sheffield, UK) was inserted into the cement mantle. Accurate fracture reduction was maintained by holding the nail in the required position and assisted manually by controlling rotation and axial alignment until setting of the cement and by using fluoroscopy intermittently. No screws were used to lock the nail as the cement/nail composite construct provided adequate axial and rotational stability in all 5 cases. Postoperatively, mobilization was started on the first day with gentle continuous passive movement exercises. Toe-touch weight-bearing was initiated within 48 hours from surgery using walking aids.

Results Postoperative Clinical and Radiological Results One patient died 2 months after surgery for reasons not related to the procedure (chronic pulmonary and heart failure). She had independent, pain-free mobility using a walking aid without however having radiologic evidence of abundant callus formation. The other 4 patients were followed up regularly at a median time of 12 months (range, 10–14 months). According to Rorabeck and

Fig. 3. A and B, Anteroposterior and lateral views of the first case one year postoperatively. There is good fracture alignment and radiological healing on both views. The arrow in B indicates smoothening of the cortical discontinuity as demonstrated in Fig. 1A with some new bone formation.

942 The Journal of Arthroplasty Vol. 25 No. 6 September 2010 Taylor's postoperative criteria [4], they all had pain-free joint motion with a median flexion of 100° (range, 90°110°); all had full extension and unaided straight leg raise. Three patients required a single walking aid and one was mobilizing independently free of aids. Two patients experienced occasional mild pain on weightbearing, whereas the remaining 2 were pain free. There was no femoral shortening, varus or valgus malalignment, or sagittal plane deformity in any case, and all patients returned to their preinjury level of ambulation at a median time of 4 months (range, 3-6 months). The median endosteal diameter at the fracture site was 40 mm (range, 35-47 mm), and the median ratio of nail length bypassing the proximal fracture line over the femoral diameter was 2.5 (range, 1.5-2.9). All fractures demonstrated radiographic union at a median of 10 months (range, 4-12 months) (Figs. 3A and B, 4A and B). The median postoperative Oxford Knee score was 34 (range, 24-42), and the median quality of life Euro

Fig. 4. A and B, Anteroposterior and lateral views of the second case 1 year postoperatively demonstrating correction of the valgus deformity with no shortening or malalignment. The arrow in panel A indicates an area of small periosteal callus formation in the region of the fresh edges of a new periprosthetic fracture demonstrated in Fig. 2B.

Quality of Life 5D score was 0.69. When comparing this score with the weighted health status general UK population sample for age and sex, the mean for octogenarian women was also found to have the exact same value of 0.69. This indicates that the procedure restored our patients' general health and quality of life. No patient required additional surgery for loss of fixation, infection or revision of the TKA. The ligamentous stability was assessed postoperatively in all cases and was found to be normal. The TKA was found to be stable radiologically and clinically in all cases postoperatively.

Discussion It is expected that Rorabeck type II fractures should be managed operatively [3,4]. Standard plating methods require extensile approaches which disturb the soft tissue envelope and carry an increased risk of infection and non-union in the elderly population [14]. Locking plate technology has proved advantageous in osteoporotic bone and can be performed through a minimally invasive approach which has led to acceptable results [5,6]. This fixation method is, however, technically demanding and recent evidence in treating B1 periprosthetic femoral fractures around hip arthroplasty raised concerns about the locking screws pull out resistance [15]. Alternatively retrograde intramedullary supracondylar nail fixation is a well-established method for treating Rorabeck type II fractures with good long term results [7,8,16]. Nailing does not disturb the soft tissue envelope at the fracture site, and biomechanical data demonstrate advantages over locking plates [17]. In addition, the surgical time is shorter, the blood loss is low, and the procedure is relatively easy to perform. Preoperative planning is crucial, however, to identify the type but also the position of the knee prosthesis in situ in order to ensure adequate access into the femoral canal for the nail insertion [18,19]. A recent systematic review by Herrera et al. [16] summarized published data from 29 case series with a total of 415 periprosthetic supracondylar fractures. They found that intramedullary nailing was associated with a significant lower complication rate and higher union rate compared to nonoperative treatment or conventional plating. Nailing, however, often fails to maintain fracture reduction in “stovepipe”-like osteoporotic femora due to limited contact surface [5]. It is therefore necessary to increase the nail/bone interface to improve torsional and axial stability. Treatment of osteoporotic fractures with cement augmentation has been described in the literature before in various other anatomical locations including vertebroplasty [20] and sacroplasty [21]. Furthermore, the combination of intramedullary nailing and PMMA cement has been used successfully in the treatment of impending pathological fractures of the femur and humerus [22,23]. PMMA cement as an adjunct has also had beneficial effects in the strength of fixation and

Nailed Cementoplasty in Periprosthetic Knee Fractures  Bobak et al

overall limb function in patients with osteoporotic intertrochanteric femoral fractures [24]. An obvious disadvantage of cement as an adjunct to fracture fixation could be healing disturbance. Evidence, however, suggests that even in the presence of PMMA for screw purchase augmentation in osteoporotic supracondylar femoral fractures, healing occurs when treated with conventional plates [25,26]. The combination of cementoplasty and retrograde intramedullary nailing offers the advantages of a quick, less invasive procedure and achieves immediate postoperative mobilization, which is of paramount importance in this selected group of octogenarians with multiple comorbidities. The cement integrates with osteoporotic bone, bridging the gap between bone and nail, simulating a stemmed cemented knee revision component, thus providing a stable and efficient construct without the need for locking screws. In addition, it is anticipated that the nail should bypass the most proximal fracture line by at least 2 ipisilateral femoral diameters to achieve sufficient axial stability and promote healing [10]. Our technical report is limited by the small number of patients and the short-term follow-up, which was adequate for assessing fracture healing but not prosthesis survival. In addition, we had no matching control group of octogenarians with significant comorbidities and the same fracture pattern treated with either conventional or locking plates or standard locked supracondylar nails to compare with. Our experience using locking plates or nails for Rorabeck type II fractures in younger patients is satisfactory and similar to the current literature [5-8]. Nailed cementoplasty is only applicable to patients who have knee prostheses in situ with an open box design. This technique is proposed not as an alternative to the standard methods of fixation of type II periprosthetic fractures but as a salvage procedure for octogenarians with advanced osteoporosis and significant comorbidities who are unfit for lengthy procedures.

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