Implant options for the treatment of intertrochanteric fractures of the hip

Transcription

1 TRAUMA Implant options for the treatment of intertrochanteric fractures of the hip RATIONALE, EVIDENCE, AND RECOMMENDATIONS A. R. Socci, N. E. Casemyr, M. P. Leslie, M. R. Baumgaertner From Yale University School of Medicine, Connecticut, United States A. R. Socci, MD, Assistant Professor N. E. Casemyr, MD, Assistant Professor, M. P. Leslie, DO, Associate Professor M. R. Baumgaertner, MD, Professor Yale University School of Medicine, Department of Orthopaedics and Rehabilitation, 800 Howard Ave, New Haven, CT 06520, USA. Correspondence should be sent to A. R. Socci; The British Editorial Society of Bone & Joint Surgery doi: / x.99b1. BJJ R1 $2.00 Bone Joint J 2017;99-B: Received 24 March 2016; Accepted after revision 17 August 2016 Aims The aim of this paper is to review the evidence relating to the anatomy of the proximal femur, the geometry of the fracture and the characteristics of implants and methods of fixation of intertrochanteric fractures of the hip. Materials and Methods Relevant papers were identified from appropriate clinical databases and a narrative review was undertaken. Results Stable, unstable, and subtrochanteric intertrochanteric fractures vary widely in their anatomical and biomechanical characteristics, as do the implants used for their fixation. The optimal choice of implant addresses the stability of the fracture and affects the outcome. Conclusion The treatment of intertrochanteric fractures of the hip has evolved along with changes in the design of the implants used to fix them, but there remains conflicting evidence to guide the choice of implant. We advocate fixation of 31A1 fractures with a sliding hip screw and all others with an intramedullary device. Cite this article: Bone Joint J 2017;99-B: Fractures of the hip are arguably the most important public health problem faced by orthopaedic surgeons. More than lowenergy fractures of the hip occur in the United States each year. 1 The International Osteoporosis Foundation 2 estimates that approximately 1.6 million such fractures occur per year worldwide, a figure which may rise to six million by Their treatment consumes a growing percentage of healthcare expenditure. 2 The goals of care are to restore function with the lowest possible rate of surgical and medical complications. Achieving stable reduction and fixation of the fracture, permitting immediate mobilisation, is key to these goals. The last 25 years has seen the introduction and increasing acceptance and use of intramedullary devices in preference to the sliding hip screw (SHS) for the treatment of intertrochanteric fractures. 3 Despite little good quality evidence to support their use, most clinicians use them for most fractures, and practice guidelines from the American Association of Orthopaedic Surgery (AAOS) 4 support their use. 5 In this paper we review the evidence and highlight the weaknesses or absence. We also present our practice with its rationale and recommendations. The pertrochanteric region has many thickenings of trabecular bone in compressive and tensile groups. The most structurally significant of these are the primary compressive trabeculae along the posteromedial femoral neck and shaft. 6 While several classification systems exist for these fractures, they are all based on the concept of stability. A stable fracture is a simple one that, once reduced and fixed, is compressed and minimally impacted by the nearly perpendicular weight-bearing force of single leg stance. 7 Unstable fractures due either to comminution, reverse oblique orientation, or both, are associated with collapse on axial loading. Both the posteromedial cortex and the lateral cortical buttress beneath the vastus ridge contribute to the stability of these fractures. The instability increases with the degree of comminution of the posteromedial cortex. Increased comminution implies less support for axial loading through cortical contact. The lateral cortex beneath the vastus ridge provides the final buttress to impaction of the fracture after fixation, further contributing to its stability and avoiding collapse. 8,9 Incompetence of either of these cortical regions therefore renders a fracture unstable. 128 THE BONE & JOINT JOURNAL

2 IMPLANT OPTIONS FOR THE TREATMENT OF INTERTROCHANTERIC FRACTURES OF THE HIP 129 Fig. 1 Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association classification of pertrochanteric fractures. Copyright the AO Foundation, Switzerland. (Source: AO Surgery Reference). The quality of reduction, regardless of the pattern of the fracture, is one of the most important modifiable factors in the management of intertrochanteric fractures. 10 The ability of the cortex to resist collapse in stable fractures depends on the restoration of cortical continuity. In unstable fractures, where the ability to restore this is limited by comminution or the orientation of the fracture, the boneimplant interface will be subject to increased stress. Implants used to fix unstable fractures must, therefore, be capable of bearing more load, in order to avoid loss of reduction through collapse. A valgus reduction is one way of increasing interfragmentary compression and of reducing bone-implant stresses, as well as minimising collapse and leg length discrepancy. Studies of implant loading confirm that the load borne by an implant is increased with varus mal-reduction and with decreasing stability of the fracture, and that in both cases an intramedullary device can bear greater load than an extramedullary device. 11,12 The Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association classification system 13 (Fig. 1) offers both a universal descriptive language and reliable evidence on prognosis, 7 and is also useful for research and has been shown to have greater inter-observer reliability than other classification systems. 14 Simple, two-part pertrochanteric fractures with a single line of extension into the medial cortex are classified as 31-A1. These fractures are stable after reduction because bony continuity is restored and a significant proportion of the load transmitted through the proximal femur can be safely borne. Multi-fragmentary pertrochanteric fractures beginning anywhere in the greater trochanter with medial extension in two or more places creating a third fracture fragment, including the lesser trochanter, are classified as 31-A2. Many of these are unstable after reduction because the medial buttress is compromised. Fracture patterns 31-A1.1 to 31-A2.1 are typically stable and those from 31-A2.2 to 31-A3.3, which have more than one intermediate fragment, are usually unstable. 15 True intertrochanteric fractures with a fracture line that passes between the trochanters, above the lesser trochanter medially and below the vastus ridge laterally are classified as 31-A3. These fractures are unstable after reduction because both posteromedial and lateral buttresses are lost. This classification is particularly valuable in its identification of reverse oblique and intertrochanteric subtrochanteric fractures as challenging to reduce and fix with stability. Involvement of the lateral cortex is only a specific criterion of fractures in the 31-A3 category and is an important factor in loss of reduction when using an extramedullary SHS system. 16 Intra-operative fracture of the lateral cortical buttress is significantly more common in A2.2 and A2.3 fractures than in A2.1 fractures, 8 emphasising the importance of recognising the A2 sub-type when choosing the implant by which it will be managed. A surgeon s familiarity with a specific implant may have a measurable effect on the operating time, the use of fluoroscopy, intra-operative blood loss and the need for transfusion, but a systematic review of the evidence reported significant heterogeneity in published data and an implantassociated effect has not therefore been shown. 17 There is an increasing cost associated with SHSs, short nails and long nails, respectively. 18,19 Intramedullary implants are between 20% and 40% more expensive than SHSs and so, if each is appropriate for fracture fixation, the less expensive device should be used. A recent American College of Surgeons National Surgical Quality Improvement Program database study reported a shorter mean post-operative length of stay following treatment with an intramedullary implant. 20 This study did not stratify the patients by the type of fracture and hence the effect was seen across all groups, implying that the greater cost of the implant may be offset against the ongoing cost of care by using the intramedullary device in all patients. Cost-effectiveness analysis that models length of stay, rehabilitation or re-operation is dependent on the data used for the model, in particular those used to inform the rate of failure. One such study suggested that extramedullary VOL. 99-B, No. 1, JANUARY 2017

3 130 A. R. SOCCI, N. E. CASEMYR, M. P. LESLIE, M. R. BAUMGAERTNER implants are more cost-effective for A2 fractures, but assumed an equivalent rate of failure between SHSs and nails. 18 Such an assumption ignores differences in outcomes, especially when considering the A2 group as a homogenous one. Late costs are more difficult to measure and tend to relate to failure, requiring prolonged rehabilitation or reoperation. 21 First-generation intramedullary implants had a significantly higher incidence of periprosthetic fracture, thereby compounding their already increased cost. A 4.5- fold increased risk of periprosthetic fracture in 1997 decreased to 1.87 in 2005 and is no longer evident in the most recent data. 22,23 Despite a large number of randomised controlled trials (RCTs), meta-analyses have not shown differences in functional outcomes between intra- and extra-medullary devices. These studies have often used inappropriate outcome measures and reported the outcome of diverse cohorts of patients, pooled without reference to pre-operative functional status. 17,24 Some authors have, however, shown differences in the rates of recovery of function. In a RCT of intramedullary versus extramedullary fixation in 210 patients with A1 or A2 fractures, Utrilla et al 25 reported no difference in outcome in stable fractures, but better mobility at one year following intramedullary fixation of unstable fractures. Improved early functional recovery following intramedullary fixation has also been shown in several studies which also recorded sliding of SHSs, indicating shortening of the femoral neck, leg length discrepancy, and/or medialisation of the shaft Pajarinen et al 26 reported improved mobility and less shortening of the femoral neck after intramedullary fixation in agreement with the findings of Hardy et al 27 of improved early mobility, less sliding and less leg length discrepancy. The early functional recovery is better in those in whom the SHS slides less, suggesting that excessive alteration of the biomechanics of the hip can impair the recovery of mobility. A recent RCT by Reindl et al 29 found less shortening of the femoral neck in the intramedullary group, but this did not significantly alter the timed up and go scores. It is likely that the ability of a patient to tolerate malunion is related to pre-injury function, but there is currently no evidence to support this as studies tend to pool all patients. Information about functional outcomes such as return to social integration, driving and participation in recreational activities is urgently needed. Implant details The length of the nail. Early intramedullary nails used for fractures of the hip were short and associated with a risk of fracture at the tip of the nail, with an incidence of 8% to 11% historically. 30 Long nails can prevent this complication but risk anterior cortical impingement or intraoperative iatrogenic fracture with incidences of 1.5% 30 and < 1% recorded. 31,32 For this reason, the surgeon must be conscious of the design of the nail including its radius of curvature and the anterior bow of the femur. A stress riser can, in this scenario, lead to a fracture which is even more challenging to manage, especially with a nail in situ. No significant difference in the rates of periprosthetic fracture between short and long nails have been recorded at one, two or five years post-operatively. 21,30 Longer nails can cost up to 45% more than short nails. 30 Lindvall et al 21 reported that, based on a rate of periprosthetic fracture of 12% and an increased cost of $439 of long nails over short, long nails were cheaper than short ones when the cost of managing complications was taken into account. A more recent study reported equivalence between short and long nails, except for hospital costs (which can include facility fees, cost of medications given, administration of the medications, lab costs, cost of surgery and anesthesia). 19 Leaving aside the biomechanically dissimilar subtrochanteric fractures, there is little evidence relating to short versus long nails in terms of functional outcome and until these data are known, meaningful assessment of cost benefit is difficult. Distal locking. The effect of distal locking on the incidence of periprosthetic fracture is not fully understood. Lindvall et al 21 reported that distal locking may be protective against periprosthetic fracture in both short and long nails. In their cohort of 609 patients, 47% of nails were distally locked but 15 of 16 periprosthetic fractures occurred in the 53% of patients with unlocked nails at 21.5 months (standard deviation (SD) 18.6) follow-up in the short nail group and 14.8 months (SD 13.8) follow-up for long nails. They also noted that patients with unlocked long nails experienced periprosthetic fracture around the shaft, while those with locked long nails had fractures at the tip of the nail. In short unlocked nails, fractures occurred at the tip of the nail, in keeping with early findings in studies of intramedullary fixation This is important as, in relative terms, it is easier to treat a diaphyseal fracture by closed reduction with the introduction of a distal locking screw than it is to perform open reduction and internal fixation of a peri-articular fracture around a locked nail. Current evidence supports distal locking in axially or rotationally unstable fractures, including those with subtrochanteric extension or comminution, or in osteoporotic femora in which it is hard to achieve an isthmic fit. 32 Femoral head fixation: blade vs screw, one vs two Some intramedullary implants use a helical blade for fixation of the femoral head instead of a cancellous screw. Biomechanical studies in artificial, cadaveric and living bone have shown that a blade resists rotational and translational displacement better 36,37 but this has not translated into evidence of a difference in rates of cut-out, complications, or post-operative function. 38,39 Consistently, loss of fixation is more related to the quality of reduction of the fracture and a high tip-apex distance (TAD) rather than the choice of implant. 37,39 THE BONE & JOINT JOURNAL

4 IMPLANT OPTIONS FOR THE TREATMENT OF INTERTROCHANTERIC FRACTURES OF THE HIP 131 The use of blades may be associated with the phenomenon of cut-through with medial perforation of the articular surface of the femoral head without loss of reduction of the fracture. 40 This is in contrast to cut-out, superior and anterior migration of the screw as the fracture displaces and the femoral head moves into varus and retroversion. In order to avoid cut-through, it has been suggested that the full length of the trajectory of the blade is not pre-drilled and that the tip of the blade should be a minimum of 10 mm from the joint surface. 40,41 There are variants with both one (uniaxial) and two (biaxial) screws in the femoral head. Greater load to failure has been reported with biaxial screws in a biomechanical study, 42 but this advantage has not been reported clinically and complications of axial and reverse axial migration (the Z and reverse Z effects) have been described. 43 A prospective RCT by Kouvidis et al 43 showed no difference in outcome (activities of daily living or mobility) between an SHS group (60 patients) and a biaxial intramedullary nail group (62 patients) at 1 year follow-up. The single systematic review of such devices suggests that biaxial fixation leads to a lower risk of post-operative periprosthetic fracture than uniaxial fixation. 44 This review examined only periprosthetic fracture however, without recording any other outcome or complication, including those specific to biaxial fixation. Proximal femoral locking plates offer a lower load to failure than cephalomedullary devices and have higher rates of mechanical failure and re-operation. 45 Much of the evidence supporting the use of newer designs of implant is biomechanical and must be interpreted carefully to understand the clinical relevance. The native hip may be loaded in different directions and different ways and the evidence should be evaluated with caution. Tip-apex distance and other targets Both cut-out and cut-through emphasise the importance of the correct placement of the screw in the femoral head, namely central and deep. 46 The TAD is an accepted and reproducible means of evaluating this. 46 A recent variation, the calcar-tad, aims to target a slightly inferior placement of the screw when using cephalomedullary devices. This reflects existing practice in both SHSs and intramedullary devices, based on there being stronger bone in the calcar and inferior femoral head. 47,48 It has not, however, been confirmed that this offers better fixation than when placing the screw in the centre of the femoral head. 49,50 In the multivariate analysis of Kashigar et al, 49 only the calcar-tad was found to be a statistically significant predictor of failure and although the authors concluded that inferior placement conferred benefit, the reduction of the fracture was classified as poor in almost half of the 77 patients at a mean follow-up of 408 days (81 days to 4.9 years). This, therefore, confounded the suggestion that the position of the screw was predictive of the outcome, as varus mal-reduction was also significantly associated with failure. Discussion Stable intertrochanteric fractures (A1 to A2.1). There is currently little evidence of the superiority of one device over another in the management of these fractures. 5,25,28,51 The quality of reduction remains paramount, with stable fractures having direct cortical contact following accurate reduction. At our institution there is a preference for SHS fixation after careful reduction. Subtrochanteric and reverse oblique fractures (A3). There is strong evidence to support the use of intramedullary fixation in subtrochanteric and reverse oblique fractures. The biomechanics of these fractures are such that fixation with a SHS is inappropriate, as the line of collapse is not perpendicular to the fracture line and the lateral cortical buttress cannot resist collapse. The use of a trochanteric sliding plate (TSP) offers increased resistance to collapse, but the fixation is less reliable than when using an intramedullary device, which offers better functional outcomes and rates of union. 27,52,53-57 Worse outcomes are also associated with the use of proximal femoral locking plates. 58 Intramedullary nails resist collapse both by their intramedullary position and by an enlarged proximal end, offering an internal buttress. The minimally invasive nature of the surgery also preserves the vastus soft tissue envelope, maintaining stability and vascularity. Unstable intertrochanteric fractures (A2.2 to A2.3). Current guidelines recommend the use of an intramedullary device for the treatment of these fractures. 5 As in subtrochanteric and reverse oblique fractures, the use of a TSP may prevent excessive collapse in unstable fractures lacking a posteromedial or lateral cortical buttress in which an SHS is used. A randomised prospective study comparing fixation using a SHS (343 patients) or intramedullary nail (341 patients) for all intertrochanteric and subtrochanteric fractures showed no long-term differences in outcome at three and 12 month follow-up, with improved early pain on mobilisation scores in the intramedullary group. 59 Importantly, a TSP was used in A3 fractures and optional in osteoporotic A1 and A2 fractures when the lateral cortical buttress was questionable. The equivalence of outcome between these constructs emphasises that maintenance of a good reduction and prevention of collapse offers optimum function. Medialisation of the femoral shaft was seen more frequently in the SHS/TSP group and was associated with increased post-operative pain. Overall, an intramedullary device appears from the evidence to offer more benefit than an SHS with TSP. Basicervical fracture. True basicervical fractures are uncommon and, although extracapsular, have similar rotational instability to those occurring more medially in the femoral neck. A simple two-part basicervical fracture requires reduction with direct cortical contact, and stable, compressed fixation. A de-rotation screw may offer increased protection against rotational loss of reduction. A comminuted fracture with basicervical extension should be treated VOL. 99-B, No. 1, JANUARY 2017

5 132 A. R. SOCCI, N. E. CASEMYR, M. P. LESLIE, M. R. BAUMGAERTNER as a comminuted, unstable intertrochanteric fracture with an intramedullary device. The role of arthroplasty. Certain unstable intertrochanteric fractures of the hip can be treated by arthroplasty. Indications include existing arthritis, osteonecrosis of the femoral head, poor quality of bone or complications following internal fixation. 60 There is limited evidence for the role of arthroplasty in treating unstable intertrochanteric fractures, with benefits including early mobilisation. 60 The surgery is technically challenging and should be undertaken by an experienced arthroplasty surgeon. In conclusion, decision-making in the management of intertrochanteric fractures requires a thorough understanding of the stability of the fracture and the implants which are available. More evidence on functional outcomes is needed, especially in higher-functioning patients. It remains of critical importance to pay careful attention to the quality of the reduction and central and deep positioning of the screw or blade, regardless of implant. Take home message: There is conflicting evidence about the choice of implant in the treatment of intertrochanteric fractures of the hip, but assessing the stability of the fracture allows one to choose between fixation using a SHS or an intramedullary device. Author contributions: A. R. Socci: Primary researcher and writer. N. E. Casemyr: Researched and wrote significant portion of introduction, Editing and revising. M. P. Leslie: Wrote a section on technical aspects of reduction which was not included, Participated in revision process. M. R. Baumgaertner: Provided necessary oversight and guidance, Focused the work on the most relevant references, concepts and controversies, Heavily involved in editing and revision. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by P. Page and first proof edited by J. Scott. References 1. No authors listed. Centers for Disease Control and Prevention: Hip Fractures Among Older Adults. (date last accessed 16 November 2016). 2. No authors listed. International Osteoporosis Foundation: Hip Fracture. (date last accessed 16 November 2016). 3. Chen F, Wang Z, Bhattacharyya T. Convergence of outcomes for hip fracture fixation by nails and plates. Clin Orthop Relat Res 2012;471: No authors listed. American Academy of Orthopaedic Surgeons: Management of Hip Fractures in the Elderly. (date last accessed 16 November 2016). 5. Roberts KC, Brox WT, Jevsevar DS, Sevarino K. Management of hip fractures in the elderly. J Am Acad Orthop Surg 2015;23: Griffen JB. The calcar redefined. 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6 IMPLANT OPTIONS FOR THE TREATMENT OF INTERTROCHANTERIC FRACTURES OF THE HIP Robinson CM, Adams CI, Craig M, et al. Implant-related fractures of the femur following hip fracture surgery. J Bone Joint Surg [Am] 2002;84-A: O Neill F, Condon F, McGloughlin T, et al. Dynamic hip screw versus DHS blade: a biomechanical comparison of the fixation achieved by each implant in bone. J Bone Joint Surg [Br] 2011;93-B: Fang C, Lau TW, Wong TM, Lee HL, Leung F. Sliding hip screw versus sliding helical blade for intertrochanteric fractures: a propensity score-matched case control study. Bone Joint J 2015;97-B: Huang X, Leung F, Liu M, et al. Is helical blade superior to screw design in terms of cut-out rate for elderly trochanteric fractures? A meta-analysis of randomized controlled trials. Eur J Orthop Surg Traumatol 2014;24: Stern R, Lübbeke A, Suva D, Miozzari H, Hoffmeyer P. Prospective randomised study comparing screw versus helical blade in the treatment of low-energy trochanteric fractures. Int Orthop 2011;35: Frei HC, Hotz T, Cadosch D, Rudin M, Käch K. Central head perforation, or cut through, caused by the helical blade of the proximal femoral nail antirotation. J Orthop Trauma 2012;26: Brunner A, Jöckel JA, Babst R. The PFNA proximal femur nail in treatment of unstable proximal femur fractures--3 cases of postoperative perforation of the helical blade into the hip joint. J Orthop Trauma 2008;22: Kubiak EN, Bong M, Park SS, et al. Intramedullary fixation of unstable intertrochanteric hip fractures: one or two lag screws. J Orthop Trauma 2004;18: Kouvidis G, Sakellariou VI, Mavrogenis AF, et al. Dual lag screw cephalomedullary nail versus the classic sliding hip screw for the stabilization of intertrochanteric fractures. A prospective randomized study. Strategies Trauma Limb Reconstr 2012;7: Norris R, Bhattacharjee D, Parker MJ. Occurrence of secondary fracture around intramedullary nails used for trochanteric hip fractures: a systematic review of 13,568 patients. Injury 2012;43: Streubel PN, Moustoukas M, Obremskey WT. Locked plating versus cephalomedullary nailing of unstable intertrochanteric femur fractures. Eur J Orthop Surg Traumatol 2016;26: Baumgaertner MR, Curtin SL, Lindskog DM, Keggi JM. The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip. J Bone Joint Surg [Am] 1995;77-A: Parker MJ. Cutting-out of the dynamic hip screw related to its position. J Bone Joint Surg [Br] 1992;74-B: Kuzyk PRT, Zdero R, Shah S, et al. Femoral head lag screw position for cephalomedullary nails: a biomechanical analysis. J Orthop Trauma 2012;26: Kashigar A, Vincent A, Gunton MJ, et al. Predictors of failure for cephalomedullary nailing of proximal femoral fractures. Bone Joint J 2014;96-B: De Bruijn K, den Hartog D, Tuinebreijer W, Roukema G. Reliability of predictors for screw cutout in intertrochanteric hip fractures. J Bone Joint Surg [Am] 2012;94- A: Varela-Egocheaga JR, Iglesias-Colao R, Suárez-Suárez MA, et al. Minimally invasive osteosynthesis in stable trochanteric fractures: a comparative study between Gotfried percutaneous compression plate and Gamma 3 intramedullary nail. Arch Orthop Trauma Surg 2009;129: Babst R, Renner N, Biedermann M, et al. Clinical results using the trochanter stabilizing plate (TSP): the modular extension of the dynamic hip screw (DHS) for internal fixation of selected unstable intertrochanteric fractures. J Orthop Trauma 1998;12: Madsen JE, Naess L, Aune AK, et al. Dynamic hip screw with trochanteric stabilizing plate in the treatment of unstable proximal femoral fractures: a comparative study with the Gamma nail and compression hip screw. J Orthop Trauma 1998;12: Miedel R, Ponzer S, Törnkvist H, Söderqvist A, Tidermark J. The standard Gamma nail or the Medoff sliding plate for unstable trochanteric and subtrochanteric fractures. A randomised, controlled trial. J Bone Joint Surg [Br] 2005;87-B: Sadowski C, Lübbeke A, Saudan M, et al. Treatment of reverse oblique and transverse intertrochanteric fractures with use of an intramedullary nail or a 95 degrees screw-plate: a prospective, randomized study. J Bone Joint Surg [Am] 2002;84- A: Schipper IB, Steyerberg EW, Castelein RM, et al. Treatment of unstable trochanteric fractures randomised comparison of the gamma nail and the proximal femoral nail. J Bone Joint Surg [Br]2004;86-B: Matre K, Havelin LI, Gjertsen JE, et al. Sliding hip screw versus IM nail in reverse oblique trochanteric and subtrochanteric fractures. A study of 2716 patients in the Norwegian Hip Fracture Register. Injury 2013;44: Kuzyk PRT, Lobo J, Whelan D, et al. Biomechanical evaluation of extramedullary versus intramedullary fixation for reverse obliquity intertrochanteric fractures. J Orthop Trauma 2009;23: Matre K, Vinje T, Havelin LI, et al. TRIGEN INTERTAN intramedullary nail versus sliding hip screw: a prospective, randomized multicenter study on pain, function, and complications in 684 patients with an intertrochanteric or subtrochanteric fracture and one year of follow-up. J Bone Joint Surg [Am] 2013;95: Mäkinen TJ, Gunton M, Fichman SG, et al. Arthroplasty for Pertrochanteric Hip Fractures. Orthop Clin North Am 2015;46: VOL. 99-B, No. 1, JANUARY 2017