Injury, Int. J. Care Injured 47 (2016) 460–464
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Retrograde femoral nailing of periprosthetic fractures around total knee replacements Mark D. Jones b,*, Charlotte Carpenter a, Stephen R. Mitchell a, Michael Whitehouse c, Sanchit Mehendale a a b c
Department of Trauma and Orthopaedics, University Hospitals Bristol NHS Foundation Trust, Upper Maudlin Street, Bristol BS2 8HQ, UK Department of Trauma and Orthopaedics, Tunbridge Wells Hospital, Maidstone and Tunbridge Wells NHS Trust, Tonbridge Road, Pembury TN2 4QJ, UK Musculoskeletal Research Unit, Level 1 Learning and Research Building, Southmead Hospital, Westbury on Trym, Bristol BS10 5NB, UK
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 14 October 2015
Introduction: The incidence of primary total knee replacement (TKR) is increasing with a resultant rise in those patients sustaining distal femoral periprosthetic fractures around TKRs. The management of these fractures pose a significant challenge. The compatibility of retrograde femoral intramedullary (IM) nails with femoral TKR components needs to be considered preoperatively when this complex pathology is addressed. The aim of this study was to update the literature and assess the compatibility of the most commonly used primary TKR prostheses and retrograde femoral IM nails using a Sawbone anatomical model. Methods and materials: Eight of the most commonly used primary TKR prostheses and four of the most commonly used retrograde femoral IM nails were identified. The femoral components of the TKRs were implanted onto left sided femoral Sawbones using the manufacturer’s guides and cutting blocks and positioned appropriately. The retrograde IM nails were inserted using the conventional entry point and a nail was deemed compatible if this was possible through the femoral prosthesis. Details of whether a posterior entry point was required to allow insertion, whether the femoral nail was scratched by the femoral TKR prosthesis on insertion and whether excess force was required to insert the retrograde femoral IM nail were recorded. Results: The Biomet AGC Cruciate Retaining (CR) and Posterior Stabilised (PS) TKR were the only prostheses that were compatible with all the nails used. The other TKR prostheses were not compatible because of the force required to gain entry, scratching of the retrograde femoral IM nail or because a posterior entry point was required to gain entry through the intercondylar notch. Conclusion: The majority of standard sized retrograde femoral nails are technically feasible for insertion through most femoral TKR components but this study has found that they are not compatible due to excessive force required for insertion, damage to the nail during insertion or the risk of anterior cortex perforation. Further studies are required to update the compatibility table and cadaveric studies would confirm the findings and allow further mechanical testing. ß 2015 Elsevier Ltd. All rights reserved.
Keywords: Knee arthroplasty Knee replacement Total Intramedullary nailing Femur Periprosthetic fracture
Introduction The management of femoral periprosthetic fractures around an existing total knee replacement (TKR) poses a significant management challenge. The population that sustain these fractures often have poor bone stock and osteopaenia. Instability of the fracture type and the risk of delayed fracture healing complicate surgical decision
* Corresponding author. E-mail address: [email protected] (M.D. Jones). http://dx.doi.org/10.1016/j.injury.2015.10.030 0020–1383/ß 2015 Elsevier Ltd. All rights reserved.
making [1]. The two main causes of supracondylar fractures around a TKR are iatrogenic and low energy trauma with the incidence ranging from 0.3 to 2.5% for primary TKR [2–8] and 1.6 to 38% for revision TKR [9]. Since one of the earliest published reports in 1981 [10], many treatment options have been proposed. Historically, these fractures were treated conservatively, with either casting, cast-bracing or with skeletal traction [2,10–13]. Minimally displaced fractures are still treated with non-weight bearing conservative management. However, the risks associated with these methods including the complications of prolonged immobility in bed, stiffness of the knee, malunion and nonunion, favouring surgical
M.D. Jones et al. / Injury, Int. J. Care Injured 47 (2016) 460–464
management. Surgical options include revision TKR with a long stemmed femoral component [2,14], open reduction and internal fixation (ORIF) with the use of buttress Plates [15,16], fixed angle devices such as the condylar screw plate and blade plate [15,17] and a Less Invasive Stabilisation System (LISS) [18,19]. In 1994, early reports were published advocating the use of a retrograde femoral intramedullary (IM) nail through the intercondylar notch of existing TKR [20,21]. Retrograde femoral IM nailing techniques offer potential advantages such as minimal soft tissue dissection, periosteal stripping and decreased postoperative stiffness. However, not all TKR prostheses are compatible with retrograde femoral IM nails as they do not afford the access to allow the IM nail to be passed through the femoral component and into the femoral canal, particularly in closed box prostheses. If access is theoretically possible, damage may be caused to titanium nails when they are passed through the prosthesis. Published reports over recent years have observed the compatibility of particular TKR prostheses with retrograde femoral IM nails; either by their theoretical compatibility due to the size of the TKR prostheses intercondylar notch size and location [22,23] or by the demonstration of a standard retrograde femoral IM nail passing into a Sawbone through the TKR femoral component [24]. As the incidence of primary and revision TKR increases, so will the number of patients presenting with this complex fracture pattern. Since the study of Currall et al. [24], new prosthesis designs have been introduced to the market. The aim of this study was to assess the compatibility of the most commonly used primary TKR prostheses and retrograde femoral IM nails for use in the management of periprosthetic fractures around TKR. Materials and methods The 10 most frequently used primary TKR in the United Kingdom (UK) were identified from the National Joint Registry (NJR) [25] as well as a newly released TKR from one of the main device companies (Table 1) used by the senior authors’ institution. A selection of commonly used retrograde femoral nails from different manufacturers (Table 2) were identified. The manufacturers were contacted to provide a sample of their prostheses for Table 1 TKR designs utilised in the study (these represent the 10 most commonly used models of knee (CR, CS and PS designs where appropriate) according to the National Joint Registry 2013 Annual Report and the newly introduced DePuy ATTUNE system. Where implants were not available from the manufacturer, these have been excluded. Manufacturer
Model
Included in study
DePuy
PFC Sigma CR PFC Sigma CS LCS Complete CR LCS Complete PS ATTUNE CR ATTUNE PS Scorpio CR Scorpio PS Triathlon CR Triathlon PS Kinemax Nexgen
Yes Yes Yes No Yes Yes Yes No Yes No No No
AGC CR AGC PS Vanguard CR Vanguard PS Genesis II CR Genesis II PS Endoplus Bicondylar
Yes Yes Yes No Yes No No
Stryker (Stryker UK Ltd, Berkshire, UK)
Zimmer (Zimmer Ltd, Swindon, UK) Biomet
Smith & Nephew Endo Plus (Endo Plus UK Ltd, Swindon, UK)
461
Table 2 Retrograde femoral intramedullary [2_TD$IF]nails used. Manufacturer
Model
Diameter (mm)
Biomet DePuy Smith & Nephew Stryker
Phoenix retrograde nail ACE retrograde femoral nail Trigen retrograde femoral nail T2 supracondylar femoral nail
10.5 10 10 10
inclusion in the study. For each of the TKR prostheses femoral components, the distal end of a left sided femoral sawbone was prepared using the appropriate manufacturers’ guides and cutting jigs and the femoral components positioned appropriately. Positioning of each femoral nail into the IM canal of the femur using the conventional entry point as specified by the manufacturers was attempted. If this entry point was not compatible, a posterior notch was made in the intercondylar region of the distal femur to allow the retrograde femoral IM nail to enter the IM canal of the femur through the intercondylar notch of the femoral component of the TKR prostheses. In this study, a posterior entry point was made by removing the posterior intercondylar notch of the femur so that the medullary canal could be accessed. A nail was deemed compatible if the retrograde femoral IM nail was positioned appropriately into the femur through the femoral prosthesis. Details including whether the nail was scratched by the femoral TKR prosthesis on insertion (Fig. 1), and whether excess force was required to insert the retrograde femoral IM nail were recorded. Excess force was defined as a force that in the opinion of the senior authors, would risk iatrogenic fracture, usually through the anterior cortex due to the posterior entry point and the bow of the retrograde femoral IM nail. Incompatibility of a nail was defined as a failure to physically pass the nail through the TKR femoral prosthesis, the requirement to use excessive force or significant damage to the IM nail including macroscopic scratches.
Results Seven of the 10 most commonly used TKR prostheses were obtained from the manufacturers, as well as the recently released ATTUNE knee prosthesis (DePuy Synthes UK, Leeds, UK) (Table 1). Four commonly used retrograde femoral IM nails (Table 2) were used in the study. The compatibility of these nails with the 8 TKR prostheses is shown in Table 3. Only the DePuy PFC Cruciate Stabilising (CS) TKR was not technically compatible with all the retrograde femoral IM nails due to [(Fig._1)TD$IG] its closed box design. However, several TKR required some force,
Fig. 1. Example of the scratches sustained to the retrograde femoral intramedullary nail on insertion through the femoral TKR component.
462 Table 3 Retrograde femoral nail compatibility with differing TKR prostheses. Posterior entry indicates that the posterior aspect of the femoral intercondylar region had to be removed to allow the retrograde femoral IM nail to be inserted into the intramedullary canal. Macroscopic scratching of the femoral prosthesis was recorded when it occurred. If a significant force was required to pass the nail correctly, then this was recorded. Compatibility indicates that the femoral nail was able to pass through the notch of the femoral prostheses into the intramedullary canal without a posterior entry point, excessive force or being scratched. Total knee replacement
Retrograde femoral nail Smith & Nephew
Biomet
Depuy
T2 supracondylar femoral nail (10 mm)
Trigen retrograde femoral nail (10 mm)
Phoenix retrograde nail (10.5 mm)
ACE retrograde femoral nail (10 mm)
Manufacturer Model
Size
Technically Posterior Scratches Force Compatible Technically Posterior Scratches Force Compatible Technically Posterior Scratches Force Compatible Technically Posterior Scratches Force Compatible feasible entry required feasible entry required feasible entry required feasible entry required
DePuy
3 4 6 5 Standard
Y Y Y Y Y
N N N N N
N N N N N
N N N N N
Y Y Y Y Y
Y Y Y N Y
N N N NA N
Y Y N NA Y
Y N N NA N
N N Y N N
Y Y Y N Y
N N N NA N
Y N N NA Y
N N N NA N
N Y Y N N
Y Y Y N Y
N N N NA N
Y N N NA Y
Y N N NA N
N Y Y N N
Y Y Y Y Y Y Y Y
Y Y N N N N N N
N N N N Y N N Y
N N N Y N N N N
N N Y N N Y Y N
Y Y Y Y Y Y Y Y
Y Y N N N N N N
Y N Y N Y Y N N
N N N Y N N N Y
N N N N N N Y N
Y Y Y Y Y Y Y Y
Y Y N N N N N N
Y Y N N N Y Y N
N N N Y Y N N Y
N N Y N N N N N
Y Y Y Y Y Y Y Y
Y Y N N N N N N
N N Y Y Y Y Y Y
N N N N N N N N
N N N N N N N N
Y Y Y Y Y
N N N N Y
N N N N Y
N N N N Y
Y Y Y Y N
Y Y Y Y Y
N N N N Y
N N N N Y
N N N N Y
Y Y Y Y N
Y Y Y Y Y
N N N N Y
N N N N Y
N N N N Y
Y Y Y Y N
Y Y Y Y Y
N N N N Y
N N N N Y
N N N N Y
Y Y Y Y N
Y Y
Y N
Y N
Y N
N Y
Y Y
Y N
Y N
Y N
N Y
Y Y
Y N
Y N
Y N
N Y
Y Y
Y N
Y N
Y N
N Y
PFC CR
PFC CS LCS Complete CR ATTUNE CR
Stryker
Biomet
Smith & Nephew
3 5 ATTUNE PS 5 Scorpio CR 7 9 Triathlon CR 4 5 Vanguard 65 mm CR AGC CR 55 mm 70 mm AGC PR 60 mm 75 mm Genesis 3 II CR 5 8
M.D. Jones et al. / Injury, Int. J. Care Injured 47 (2016) 460–464
Stryker
[(Fig._2)TD$IG]
M.D. Jones et al. / Injury, Int. J. Care Injured 47 (2016) 460–464
463
or resulted in scratching of the femoral IM nail, particularly if a posterior entry point was required. As such, the Biomet AGC Cruciate Retaining (CR) and Posterior Stabilising (PS) (Biomet UK Ltd, Maidenhead, UK) TKR were the only prostheses compatible with all nails in all sizes of femoral component. Discussion Supracondylar femoral fractures around TKR pose a significant treatment dilemma. Retrograde nails are an accepted treatment modality, via the intercondylar notch of the femoral prostheses. The majority of standard sized retrograde femoral nails are technically feasible for insertion through most femoral TKR components. However, in this study, these were not deemed compatible, due to damage to the IM nail, the amount of force required for insertion and the position of the entry point required for successful insertion. The only TKR femoral prosthesis that is compatible for all sizes of femoral component and for both CR and PS knee systems was the Biomet AGC TKR. Currall et al. [24] studied the compatibility, of the most commonly used TKRs at the time of the study, and their compatibility with a standard 10 mm Trigen (Smith & Nephew UK Ltd, London, UK) retrograde femoral IM nail. Thompson et al. [23] have more recently published their study extensively listing the intercondylar notch dimensions of all the available TKR prostheses. Our study uses the current most popular TKRs in use according to the National Joint Registry of England, Wales and Northern Ireland [25] and assesses not only the feasibility, but more importantly their compatibility with a range of retrograde femoral IM nails, demonstrating the technical difficulties which may be encountered. The DePuy PFC PS TKR has an intercondylar notch size of 11.94 12.97 mm2[1_TD$IF] and one would expect that a retrograde femoral IM nail with a smaller diameter than this intercondylar notch size would be compatible as stated in previous studies [23,24]. Despite this, we found it was impossible to insert the 10 mm Smith & Nephew Trigen retrograde femoral nail, the 10.5 mm Biomet Phoenix retrograde nail or the 10 mm DePuy ACE retrograde femoral nail through the intercondylar notch of the size 5 DePuy PFC PS femoral TKR component (Fig. 2) due to the nature of its closed box design and the bend in the distal aspect of the retrograde femoral IM nails. Currall et al. [24] and Thompson et al. [23] have highlighted the importance of not only the intercondylar notch distance, but also the anteroposterior position of the notch for the TKR to be compatible with retrograde femoral IM nails. A TKR with a posteriorly placed notch (DePuy ATTUNE CR and Smith & Nephew Genesis II CR) on the femoral component were less likely to be compatible with retrograde femoral nails due to the standard entry point of the nail being covered by the femoral prosthesis (Fig. 3). This led to the prosthesis being technically feasible in this Sawbone study, but this may not be possible in vivo due to the extreme flexion required to access the adapted posterior entry point required for insertion of the nail. Inability to access the posterior entry point intraoperatively may lead to perforation of the anterior cortex if insertion of the nail was attempted and therefore the DePuy ATTUNE CR (sizes 3 and 5) and the Smith & Nephew Genesis II (sizes 3 and 5) TKR were incompatible. Currall et al. [24] and Thompson et al. [23] have previously demonstrated this for all component sizes of the Smith and Nephew Genesis II TKR but unlike their studies, we demonstrated that the size 8 femoral component is in fact compatible with the retrograde femoral IM nails used. This is the first study demonstrating the incompatibility of the DePuy ATTUNE CR TKR with retrograde femoral IM nailing. Incompatibility of a nail was defined as a failure to physically pass the nail through the TKR femoral prosthesis, the requirement
Fig. 2. Size 5 DePuy PFC CS femoral component and the Smith & Nephew 10 mm Trigen retrograde femoral nail demonstrating incompatibility due to the inability to insert the nail beyond the illustrated position.
to use excessive force or significant damage to the IM nail including macroscopic scratches. However, if physical incompatibility were the sole measure the remaining results obtained are in keeping with previously published results [23,24]. The authors suggest that those retrograde femoral IM nails that were scratched or required excessive force to be inserted successfully into the femoral canal through the intercondylar notch are in fact incompatible and should not be used. Reasons for this include the high risk of iatrogenic fracture, the risk of fatigue failure of the retrograde femoral IM nail as a result of the scratches, loosening of the femoral prosthesis and the in vivo impracticalities of the extreme posterior entry points required for insertion. There were several limitations to this study. The sawbones used were all the same size, however different sizes of femoral TKR components were implanted onto these. As the fit was not anatomical, the accuracy of the position can not be guaranteed. This would have a direct effect on where the notch was located on the femur, and therefore may have altered the femoral nail entry point, the damage to the IM nails and the force required to insert the retrograde femoral IM nail. We only used 4 models of retrograde femoral IM nails, each of one size. Apart from the anteroposterior position of the notch on the femoral prosthesis dictating the femoral nail entry point, this was also associated with the shape of the femoral nail, in particularly the anterior bow. This also played a large role in the force required to successfully insert the retrograde femoral IM nails into the femur through the femoral prostheses intercondylar notch. In order to more widely apply the results of this study, assessment of more brands of and diameters of retrograde nails would be required.
[(Fig._3)TD$IG]
464
M.D. Jones et al. / Injury, Int. J. Care Injured 47 (2016) 460–464
Acknowledgements Source of funding: None declared.
References
Fig. 3. The importance of the anteroposterior location of the intercondylar notch of the femoral TKR component for compatibility with retrograde femoral intramedullary nails.
In practice, not all TKR are compatible with retrograde nailing of the femur. This study provides a contemporary compatibility table for the most commonly used modern TKR and retrograde femoral nails. The authors recommend that this paper be used to guide and to inform surgical decision making regarding the management of periprosthetic supracondylar fractures, including the feasibility of use of retrograde femoral IM nail and the size and brand of compatible nails. The significance of a scratched nail and femoral prosthesis has not been established from this study, but the authors feel this would lead to an unacceptable risk of hardware failure. Further studies will be required to update the compatibility table as novel designs are introduced. Performance of cadaveric studies would allow confirmation of the findings in this study and also allow mechanical testing to be performed to assess whether damage to retrograde nails during insertion through TKRs leads to compromised load to failure of the construct. Conflict of interest Mark Jones: No conflict of interest. Charlotte Carpenter: No conflict of interest. Stephen Mitchell: No conflict of interest. Michael Whitehouse: Speakers bureau/paid presentations by DePuy and Heraeus (money paid into University administered research fund, research support as Prinicipal Investigator by DePuy (research grant for consumables), travelling fellowship from Zimmer administered by the BOA and he is on the Hip International Editorial Board. Sanchit Mehendale: No conflict of interest.
[1] Kim KI, Egol KA, Hozack WJ, Parvizi J. Periprosthetic fractures after total knee arthroplasties. Clin Orthop Relat Res 2006;446:167–75. [2] Figgie MP, Goldberg VM, Figgie HE, Sobel M. The results of treatment of supracondylar fracture above total knee arthroplasty. J Arthroplast 1990;5: 267–76. [3] Ehner MK, Ganz R. Internal fixation of supracondylar fracture after condylar total knee arthroplasty. Clin Orthop Relat Res 1993;293:219–24. [4] Rorabeck CH, Tayloy JW. Periprosthetic fractures of the femur complicating total knee arthroplasty. Orthop Clin North Am 1999;30:265–77. [5] Aaron RK, Scott R. Supracondylar fracture of the femur after total knee arthroplasty. Clin Orthop Relat Res 1987;13:136–9. [6] Culp RW, Schmidt RG, Hanks G, Mak A, Esterha JL, Heppenstall RB. Supracondylar fracture of the femur following prosthetic knee arthroplasty. Clin Orthop Relat Res 1987;72:212–22. [7] Hanks GA, Mathews HH, Routson GW, Loughran TP. Supracondylar fracture of the femur following total knee arthroplasty. J Arthroplast 1989;4:289–92. [8] Dennis DA. Periprosthetic fractures following total knee arthroplasty. J Bone J Surg 2001;83-A:120–30. [9] Rayan F, Konan S, Haddad FS. A review of periprosthetic fractures around total knee arthroplasties. Curr Orthop 2008;22:52–61. [10] Hirsh DM, Bhalla S, Roffman M. Supracondylar fracture of the femur following total knee replacement. Report of four cases. J Bone Joint Surg 1981;63-A: 162–3. [11] Merkel KD, Johnson Jr EW. Supracondylar fracture of the femur after total knee arthroplasty. J Bone Joint Surg 1986;68-A:29–43. [12] Slsto DJ, Lachiewicz PF, Insall JN. Treatment of supracondylar fractures following prosthetic arthroplasty of the knee. Clin Orthop Relat Res 1985;196:265–72. [13] Cain PR, Rubash HE, Wissinger HA, McClain EJ. Periprosthetic femoral fractures following total knee arthroplasty. Clin Orthop Relat Res 1986;208:205–14. [14] Backstein D, Safir O, Gross A. Periprosthetic fractures of the knee. J Arthroplast 2007;22:45–9. [15] Healy WL, Siliski JM, Incavo SJ. Operative treatment of distal femoral fractures proximal to total knee replacements. J Bone Joint Surg 1993;75-A:27–34. [16] Zehntner MK, Ganz R. Internal fixation of supracondylar fractures after condylar total knee arthroplasty. Clin Orthop Relat Res 1993;293:219–24. [17] Cusick RP, Lucas GL, McQueen DA, Graber CD. Construct stiffness of different fixation methods for supracondylar femoral fractures above total knee prostheses. Am J Orthop (Belle Mead NJ) 2000;29:695–9. [18] Kregor PJ, Stannard J, Zlowodzki M, Cole PA, Alonso J. Distal femoral fracture fixation utilizing the Less Invasive Stabilization System (LISS): the technique and early results. Injury 2001;32:32–47. [19] Bong MR, Egol KA, Koval KJ, Kummer FJ, Su ET, Lesaka K, et al. Comparison of the LISS and a retrograde-inserted supracondylar intramedullary nail for fixation of a periprosthetic distal femur fracture proximal to a total knee arthroplasty. J Arthroplast 2002;17:876–81. [20] McLaren AC, Dupont JA, Schroeber DC. Open reduction internal fixation of supracondylar fractures above total knee arthroplasties using the intramedullary supracondylar rod. Clin Orthop Relat Res 1994;302:194–6. [21] Iannacone WM, Bennett FS, DeLong Jr WG, Born CT, Dalsey RM. Initial experience with the treatment of supracondylar femoral fractures using the supracondylar intramedullary nail: a preliminary report. J Orthop Trauma 1994;8:322–7. [22] Su ET, DeWal H, Di Cesare PE. Periprosthetic femoral fractures above total knee replacements. J Am Acad Orthop Surg 2004;12:12–20. [23] Thompson SM, Lindisfarne EOA, Bradley N, Solan M. Periprosthetic supracondylar femoral fractures above a total knee replacement: compatibility guide for fixation with a retrograde intramedullary nail. J Arthroplast 2014;29: 1639–41. [24] Currall VA, Kulkarni M, Harries WJ. Retrograde nailing for supracondylar fracture around total knee replacement: a compatibility study using the Trigen supracondylar nail. Knee 2007;14:208–11. [25] National Joint Registry for England, Wales and Northern Ireland. 10th Annual Report, 2013. Available from: hhttp://www.njrcentre.org.uk/njrcentre/Portals/ 0/Documents/England/Reports/10th_annual_report/ NJR%2010th%20Annual%20Report%202013%20B.pdfi.
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Retrograde femoral nailing of periprosthetic fractures around total knee replacements Mark D. Jones b,*, Charlotte Carpenter a, Stephen R. Mitchell a, Michael Whitehouse c, Sanchit Mehendale a a b c
Department of Trauma and Orthopaedics, University Hospitals Bristol NHS Foundation Trust, Upper Maudlin Street, Bristol BS2 8HQ, UK Department of Trauma and Orthopaedics, Tunbridge Wells Hospital, Maidstone and Tunbridge Wells NHS Trust, Tonbridge Road, Pembury TN2 4QJ, UK Musculoskeletal Research Unit, Level 1 Learning and Research Building, Southmead Hospital, Westbury on Trym, Bristol BS10 5NB, UK
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 14 October 2015
Introduction: The incidence of primary total knee replacement (TKR) is increasing with a resultant rise in those patients sustaining distal femoral periprosthetic fractures around TKRs. The management of these fractures pose a significant challenge. The compatibility of retrograde femoral intramedullary (IM) nails with femoral TKR components needs to be considered preoperatively when this complex pathology is addressed. The aim of this study was to update the literature and assess the compatibility of the most commonly used primary TKR prostheses and retrograde femoral IM nails using a Sawbone anatomical model. Methods and materials: Eight of the most commonly used primary TKR prostheses and four of the most commonly used retrograde femoral IM nails were identified. The femoral components of the TKRs were implanted onto left sided femoral Sawbones using the manufacturer’s guides and cutting blocks and positioned appropriately. The retrograde IM nails were inserted using the conventional entry point and a nail was deemed compatible if this was possible through the femoral prosthesis. Details of whether a posterior entry point was required to allow insertion, whether the femoral nail was scratched by the femoral TKR prosthesis on insertion and whether excess force was required to insert the retrograde femoral IM nail were recorded. Results: The Biomet AGC Cruciate Retaining (CR) and Posterior Stabilised (PS) TKR were the only prostheses that were compatible with all the nails used. The other TKR prostheses were not compatible because of the force required to gain entry, scratching of the retrograde femoral IM nail or because a posterior entry point was required to gain entry through the intercondylar notch. Conclusion: The majority of standard sized retrograde femoral nails are technically feasible for insertion through most femoral TKR components but this study has found that they are not compatible due to excessive force required for insertion, damage to the nail during insertion or the risk of anterior cortex perforation. Further studies are required to update the compatibility table and cadaveric studies would confirm the findings and allow further mechanical testing. ß 2015 Elsevier Ltd. All rights reserved.
Keywords: Knee arthroplasty Knee replacement Total Intramedullary nailing Femur Periprosthetic fracture
Introduction The management of femoral periprosthetic fractures around an existing total knee replacement (TKR) poses a significant management challenge. The population that sustain these fractures often have poor bone stock and osteopaenia. Instability of the fracture type and the risk of delayed fracture healing complicate surgical decision
* Corresponding author. E-mail address: [email protected] (M.D. Jones). http://dx.doi.org/10.1016/j.injury.2015.10.030 0020–1383/ß 2015 Elsevier Ltd. All rights reserved.
making [1]. The two main causes of supracondylar fractures around a TKR are iatrogenic and low energy trauma with the incidence ranging from 0.3 to 2.5% for primary TKR [2–8] and 1.6 to 38% for revision TKR [9]. Since one of the earliest published reports in 1981 [10], many treatment options have been proposed. Historically, these fractures were treated conservatively, with either casting, cast-bracing or with skeletal traction [2,10–13]. Minimally displaced fractures are still treated with non-weight bearing conservative management. However, the risks associated with these methods including the complications of prolonged immobility in bed, stiffness of the knee, malunion and nonunion, favouring surgical
M.D. Jones et al. / Injury, Int. J. Care Injured 47 (2016) 460–464
management. Surgical options include revision TKR with a long stemmed femoral component [2,14], open reduction and internal fixation (ORIF) with the use of buttress Plates [15,16], fixed angle devices such as the condylar screw plate and blade plate [15,17] and a Less Invasive Stabilisation System (LISS) [18,19]. In 1994, early reports were published advocating the use of a retrograde femoral intramedullary (IM) nail through the intercondylar notch of existing TKR [20,21]. Retrograde femoral IM nailing techniques offer potential advantages such as minimal soft tissue dissection, periosteal stripping and decreased postoperative stiffness. However, not all TKR prostheses are compatible with retrograde femoral IM nails as they do not afford the access to allow the IM nail to be passed through the femoral component and into the femoral canal, particularly in closed box prostheses. If access is theoretically possible, damage may be caused to titanium nails when they are passed through the prosthesis. Published reports over recent years have observed the compatibility of particular TKR prostheses with retrograde femoral IM nails; either by their theoretical compatibility due to the size of the TKR prostheses intercondylar notch size and location [22,23] or by the demonstration of a standard retrograde femoral IM nail passing into a Sawbone through the TKR femoral component [24]. As the incidence of primary and revision TKR increases, so will the number of patients presenting with this complex fracture pattern. Since the study of Currall et al. [24], new prosthesis designs have been introduced to the market. The aim of this study was to assess the compatibility of the most commonly used primary TKR prostheses and retrograde femoral IM nails for use in the management of periprosthetic fractures around TKR. Materials and methods The 10 most frequently used primary TKR in the United Kingdom (UK) were identified from the National Joint Registry (NJR) [25] as well as a newly released TKR from one of the main device companies (Table 1) used by the senior authors’ institution. A selection of commonly used retrograde femoral nails from different manufacturers (Table 2) were identified. The manufacturers were contacted to provide a sample of their prostheses for Table 1 TKR designs utilised in the study (these represent the 10 most commonly used models of knee (CR, CS and PS designs where appropriate) according to the National Joint Registry 2013 Annual Report and the newly introduced DePuy ATTUNE system. Where implants were not available from the manufacturer, these have been excluded. Manufacturer
Model
Included in study
DePuy
PFC Sigma CR PFC Sigma CS LCS Complete CR LCS Complete PS ATTUNE CR ATTUNE PS Scorpio CR Scorpio PS Triathlon CR Triathlon PS Kinemax Nexgen
Yes Yes Yes No Yes Yes Yes No Yes No No No
AGC CR AGC PS Vanguard CR Vanguard PS Genesis II CR Genesis II PS Endoplus Bicondylar
Yes Yes Yes No Yes No No
Stryker (Stryker UK Ltd, Berkshire, UK)
Zimmer (Zimmer Ltd, Swindon, UK) Biomet
Smith & Nephew Endo Plus (Endo Plus UK Ltd, Swindon, UK)
461
Table 2 Retrograde femoral intramedullary [2_TD$IF]nails used. Manufacturer
Model
Diameter (mm)
Biomet DePuy Smith & Nephew Stryker
Phoenix retrograde nail ACE retrograde femoral nail Trigen retrograde femoral nail T2 supracondylar femoral nail
10.5 10 10 10
inclusion in the study. For each of the TKR prostheses femoral components, the distal end of a left sided femoral sawbone was prepared using the appropriate manufacturers’ guides and cutting jigs and the femoral components positioned appropriately. Positioning of each femoral nail into the IM canal of the femur using the conventional entry point as specified by the manufacturers was attempted. If this entry point was not compatible, a posterior notch was made in the intercondylar region of the distal femur to allow the retrograde femoral IM nail to enter the IM canal of the femur through the intercondylar notch of the femoral component of the TKR prostheses. In this study, a posterior entry point was made by removing the posterior intercondylar notch of the femur so that the medullary canal could be accessed. A nail was deemed compatible if the retrograde femoral IM nail was positioned appropriately into the femur through the femoral prosthesis. Details including whether the nail was scratched by the femoral TKR prosthesis on insertion (Fig. 1), and whether excess force was required to insert the retrograde femoral IM nail were recorded. Excess force was defined as a force that in the opinion of the senior authors, would risk iatrogenic fracture, usually through the anterior cortex due to the posterior entry point and the bow of the retrograde femoral IM nail. Incompatibility of a nail was defined as a failure to physically pass the nail through the TKR femoral prosthesis, the requirement to use excessive force or significant damage to the IM nail including macroscopic scratches.
Results Seven of the 10 most commonly used TKR prostheses were obtained from the manufacturers, as well as the recently released ATTUNE knee prosthesis (DePuy Synthes UK, Leeds, UK) (Table 1). Four commonly used retrograde femoral IM nails (Table 2) were used in the study. The compatibility of these nails with the 8 TKR prostheses is shown in Table 3. Only the DePuy PFC Cruciate Stabilising (CS) TKR was not technically compatible with all the retrograde femoral IM nails due to [(Fig._1)TD$IG] its closed box design. However, several TKR required some force,
Fig. 1. Example of the scratches sustained to the retrograde femoral intramedullary nail on insertion through the femoral TKR component.
462 Table 3 Retrograde femoral nail compatibility with differing TKR prostheses. Posterior entry indicates that the posterior aspect of the femoral intercondylar region had to be removed to allow the retrograde femoral IM nail to be inserted into the intramedullary canal. Macroscopic scratching of the femoral prosthesis was recorded when it occurred. If a significant force was required to pass the nail correctly, then this was recorded. Compatibility indicates that the femoral nail was able to pass through the notch of the femoral prostheses into the intramedullary canal without a posterior entry point, excessive force or being scratched. Total knee replacement
Retrograde femoral nail Smith & Nephew
Biomet
Depuy
T2 supracondylar femoral nail (10 mm)
Trigen retrograde femoral nail (10 mm)
Phoenix retrograde nail (10.5 mm)
ACE retrograde femoral nail (10 mm)
Manufacturer Model
Size
Technically Posterior Scratches Force Compatible Technically Posterior Scratches Force Compatible Technically Posterior Scratches Force Compatible Technically Posterior Scratches Force Compatible feasible entry required feasible entry required feasible entry required feasible entry required
DePuy
3 4 6 5 Standard
Y Y Y Y Y
N N N N N
N N N N N
N N N N N
Y Y Y Y Y
Y Y Y N Y
N N N NA N
Y Y N NA Y
Y N N NA N
N N Y N N
Y Y Y N Y
N N N NA N
Y N N NA Y
N N N NA N
N Y Y N N
Y Y Y N Y
N N N NA N
Y N N NA Y
Y N N NA N
N Y Y N N
Y Y Y Y Y Y Y Y
Y Y N N N N N N
N N N N Y N N Y
N N N Y N N N N
N N Y N N Y Y N
Y Y Y Y Y Y Y Y
Y Y N N N N N N
Y N Y N Y Y N N
N N N Y N N N Y
N N N N N N Y N
Y Y Y Y Y Y Y Y
Y Y N N N N N N
Y Y N N N Y Y N
N N N Y Y N N Y
N N Y N N N N N
Y Y Y Y Y Y Y Y
Y Y N N N N N N
N N Y Y Y Y Y Y
N N N N N N N N
N N N N N N N N
Y Y Y Y Y
N N N N Y
N N N N Y
N N N N Y
Y Y Y Y N
Y Y Y Y Y
N N N N Y
N N N N Y
N N N N Y
Y Y Y Y N
Y Y Y Y Y
N N N N Y
N N N N Y
N N N N Y
Y Y Y Y N
Y Y Y Y Y
N N N N Y
N N N N Y
N N N N Y
Y Y Y Y N
Y Y
Y N
Y N
Y N
N Y
Y Y
Y N
Y N
Y N
N Y
Y Y
Y N
Y N
Y N
N Y
Y Y
Y N
Y N
Y N
N Y
PFC CR
PFC CS LCS Complete CR ATTUNE CR
Stryker
Biomet
Smith & Nephew
3 5 ATTUNE PS 5 Scorpio CR 7 9 Triathlon CR 4 5 Vanguard 65 mm CR AGC CR 55 mm 70 mm AGC PR 60 mm 75 mm Genesis 3 II CR 5 8
M.D. Jones et al. / Injury, Int. J. Care Injured 47 (2016) 460–464
Stryker
[(Fig._2)TD$IG]
M.D. Jones et al. / Injury, Int. J. Care Injured 47 (2016) 460–464
463
or resulted in scratching of the femoral IM nail, particularly if a posterior entry point was required. As such, the Biomet AGC Cruciate Retaining (CR) and Posterior Stabilising (PS) (Biomet UK Ltd, Maidenhead, UK) TKR were the only prostheses compatible with all nails in all sizes of femoral component. Discussion Supracondylar femoral fractures around TKR pose a significant treatment dilemma. Retrograde nails are an accepted treatment modality, via the intercondylar notch of the femoral prostheses. The majority of standard sized retrograde femoral nails are technically feasible for insertion through most femoral TKR components. However, in this study, these were not deemed compatible, due to damage to the IM nail, the amount of force required for insertion and the position of the entry point required for successful insertion. The only TKR femoral prosthesis that is compatible for all sizes of femoral component and for both CR and PS knee systems was the Biomet AGC TKR. Currall et al. [24] studied the compatibility, of the most commonly used TKRs at the time of the study, and their compatibility with a standard 10 mm Trigen (Smith & Nephew UK Ltd, London, UK) retrograde femoral IM nail. Thompson et al. [23] have more recently published their study extensively listing the intercondylar notch dimensions of all the available TKR prostheses. Our study uses the current most popular TKRs in use according to the National Joint Registry of England, Wales and Northern Ireland [25] and assesses not only the feasibility, but more importantly their compatibility with a range of retrograde femoral IM nails, demonstrating the technical difficulties which may be encountered. The DePuy PFC PS TKR has an intercondylar notch size of 11.94 12.97 mm2[1_TD$IF] and one would expect that a retrograde femoral IM nail with a smaller diameter than this intercondylar notch size would be compatible as stated in previous studies [23,24]. Despite this, we found it was impossible to insert the 10 mm Smith & Nephew Trigen retrograde femoral nail, the 10.5 mm Biomet Phoenix retrograde nail or the 10 mm DePuy ACE retrograde femoral nail through the intercondylar notch of the size 5 DePuy PFC PS femoral TKR component (Fig. 2) due to the nature of its closed box design and the bend in the distal aspect of the retrograde femoral IM nails. Currall et al. [24] and Thompson et al. [23] have highlighted the importance of not only the intercondylar notch distance, but also the anteroposterior position of the notch for the TKR to be compatible with retrograde femoral IM nails. A TKR with a posteriorly placed notch (DePuy ATTUNE CR and Smith & Nephew Genesis II CR) on the femoral component were less likely to be compatible with retrograde femoral nails due to the standard entry point of the nail being covered by the femoral prosthesis (Fig. 3). This led to the prosthesis being technically feasible in this Sawbone study, but this may not be possible in vivo due to the extreme flexion required to access the adapted posterior entry point required for insertion of the nail. Inability to access the posterior entry point intraoperatively may lead to perforation of the anterior cortex if insertion of the nail was attempted and therefore the DePuy ATTUNE CR (sizes 3 and 5) and the Smith & Nephew Genesis II (sizes 3 and 5) TKR were incompatible. Currall et al. [24] and Thompson et al. [23] have previously demonstrated this for all component sizes of the Smith and Nephew Genesis II TKR but unlike their studies, we demonstrated that the size 8 femoral component is in fact compatible with the retrograde femoral IM nails used. This is the first study demonstrating the incompatibility of the DePuy ATTUNE CR TKR with retrograde femoral IM nailing. Incompatibility of a nail was defined as a failure to physically pass the nail through the TKR femoral prosthesis, the requirement
Fig. 2. Size 5 DePuy PFC CS femoral component and the Smith & Nephew 10 mm Trigen retrograde femoral nail demonstrating incompatibility due to the inability to insert the nail beyond the illustrated position.
to use excessive force or significant damage to the IM nail including macroscopic scratches. However, if physical incompatibility were the sole measure the remaining results obtained are in keeping with previously published results [23,24]. The authors suggest that those retrograde femoral IM nails that were scratched or required excessive force to be inserted successfully into the femoral canal through the intercondylar notch are in fact incompatible and should not be used. Reasons for this include the high risk of iatrogenic fracture, the risk of fatigue failure of the retrograde femoral IM nail as a result of the scratches, loosening of the femoral prosthesis and the in vivo impracticalities of the extreme posterior entry points required for insertion. There were several limitations to this study. The sawbones used were all the same size, however different sizes of femoral TKR components were implanted onto these. As the fit was not anatomical, the accuracy of the position can not be guaranteed. This would have a direct effect on where the notch was located on the femur, and therefore may have altered the femoral nail entry point, the damage to the IM nails and the force required to insert the retrograde femoral IM nail. We only used 4 models of retrograde femoral IM nails, each of one size. Apart from the anteroposterior position of the notch on the femoral prosthesis dictating the femoral nail entry point, this was also associated with the shape of the femoral nail, in particularly the anterior bow. This also played a large role in the force required to successfully insert the retrograde femoral IM nails into the femur through the femoral prostheses intercondylar notch. In order to more widely apply the results of this study, assessment of more brands of and diameters of retrograde nails would be required.
[(Fig._3)TD$IG]
464
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Acknowledgements Source of funding: None declared.
References
Fig. 3. The importance of the anteroposterior location of the intercondylar notch of the femoral TKR component for compatibility with retrograde femoral intramedullary nails.
In practice, not all TKR are compatible with retrograde nailing of the femur. This study provides a contemporary compatibility table for the most commonly used modern TKR and retrograde femoral nails. The authors recommend that this paper be used to guide and to inform surgical decision making regarding the management of periprosthetic supracondylar fractures, including the feasibility of use of retrograde femoral IM nail and the size and brand of compatible nails. The significance of a scratched nail and femoral prosthesis has not been established from this study, but the authors feel this would lead to an unacceptable risk of hardware failure. Further studies will be required to update the compatibility table as novel designs are introduced. Performance of cadaveric studies would allow confirmation of the findings in this study and also allow mechanical testing to be performed to assess whether damage to retrograde nails during insertion through TKRs leads to compromised load to failure of the construct. Conflict of interest Mark Jones: No conflict of interest. Charlotte Carpenter: No conflict of interest. Stephen Mitchell: No conflict of interest. Michael Whitehouse: Speakers bureau/paid presentations by DePuy and Heraeus (money paid into University administered research fund, research support as Prinicipal Investigator by DePuy (research grant for consumables), travelling fellowship from Zimmer administered by the BOA and he is on the Hip International Editorial Board. Sanchit Mehendale: No conflict of interest.
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