Rationale

There are numerous implant options available and a growing trend toward the use of CMNs.¹ Implant options can be roughly separated into extramedullary implants (of which the SHS is the most common) and intramedullary implants (of which a CMN is the most common). Choosing the most appropriate implant for a specific patient allows the surgeon to optimize the patient’s outcome while controlling cost.

Clinical comment

Many hip fracture failures stem from an inappropriate implant utilization, which leads to failure, typically represented by cutout, varus collapse, or medialization of the femoral shaft.

Available literature and quality of the evidence

Numerous prospective, randomized controlled trials (RCTs) have evaluated implants for treatment of extracapsular hip fractures. We focused on those carried out after the year 2000 to focus on current implant design.

Findings

Early studies suggested an increased rate of complications, specifically periprosthetic fractures, in hip fractures treated with a short CMN.^2,3 However, after design modifications were made to these devices, Bhandari et al. conducted a meta‐analysis in 2009 to re‐evaluate this.⁴ They found in early studies (conducted before 2000) that short nails had an increased relative risk of fracture of 4.5 (95% confidence interval [CI]: 1.78–11.36), but that in studies performed after 2000 the relative risk (RR) was not significantly increased (RR = 1.65; 95% CI: 0.50–5.44, p = 0.41). They advise that early studies comparing nails to SHSs for the treatment of extracapsular hip fractures should be interpreted with caution as they may not be applicable to current technology.

Small differences or trends in secondary outcomes such as blood loss, operating room time, early mobilization, or pain have varied in significance depending on the study evaluated. However, our main outcome of interest (implant failure necessitating re‐operation) has repeatedly been shown to be equivalent in most fracture patterns. Harrington compared a hip screw (n = 52) to an intramedullary device (n = 50) for unstable intertrochanteric hip fractures and found no difference in the rate of re‐operation relative to implant used.⁵ They noted in all cases of cut‐out the tip–apex distance was greater than 25 mm, suggesting surgical technique was more important than implant choice. Little compared a long, statically locked CMN (n = 92) to an SHS (n = 98) in a prospective randomized trial of AO/OTA type 31A fractures excluding only those with subtrochanteric extension. They found no difference in the rate of union, implant failure, or re‐operation.⁶ A Cochrane review of 43 trials performed in 2010 evaluated intramedullary versus extramedullary implants for extracapsular hip fractures. They found no compelling data to suggest intramedullary fixation provided better outcomes than the SHS, and instead found it may increase complications.⁷

Since this review, several RCTs have found no difference in revision or re‐operation rates between CMN and SHS.^8–12

A common belief is that fractures with subtrochanteric extension, reverse obliquity, an incompetent lateral wall, or incompetent calcar (the AO/OTA 31A3 fractures) benefit from intramedullary fixation. Sadowski et al. compared intramedullary versus extramedullary fixation in the treatment of AO/OTA 31A3 injuries.¹³ Thirty‐nine patients were randomized to CMN (n = 20) or a 95° fixed angle extramedullary device (n = 19). There were six implant failures and one nonunion in the 19 patients treated with the extramedullary device versus zero implant failures and one nonunion in the CMN group at one year (p = 0.007). Kuzyk et al. performed a meta‐analysis of studies looking at subtrochanteric or intertrochanteric fractures with subtrochanteric extension.¹⁴ They identified three level I studies and nine level IV studies. A pooled analysis of fixation failure in the level I studies trended toward a decreased risk of failure with intramedullary fixation (RR = 0.287; 95% CI: 0.062–1.327). Matre et al. reviewed the Norwegian registry data of 2716 patients with AO/OTA 31–A3 or subtrochanteric fractures treated with an SHS (n = 1792) or an intramedullary nail (IMN) (n = 924).¹⁵ At one year, the rate of re‐operation was increased in the SHS (6.4%) than nail group (3.8%). A Cox regression analysis found the use of an SHS carried an RR of 1.43 for re‐operation (95% CI: 1.01–2.03). Finally, in 2015, the American Academy of Orthopaedic Surgeons released evidence based clinical practice guidelines on the management of hip fractures in the elderly.¹⁶ In their final report, they used three high and two moderate strength studies to conclude that there is strong evidence to support the use of a cephalomedullary device in the use of subtrochanteric and reverse obliquity intertrochanteric hip fractures.

Swart et al. used these data to ask whether cost‐effective decision‐making could guide implant choices based on fracture pattern. They used an expected‐value decision‐analysis model to compare SHS versus nail for the treatment of AO/OTA 31 injuries. Their model was sensitive to the failure rate and implant cost. For A1 fractures, the SHS and for A3 fractures the nail always provided more value.¹⁷ For A2 injuries, there was discrepancy, depending on the fixation failure rate used, but under most conditions, the SHS was favored.

Lastly, Palm et al. reported an impressive series of data looking at 1000 geriatric hip fractures before and after the implementation of a defined treatment algorithm. Implant choice was dictated by fracture pattern with AO/OTA 31A1 and 31A2.1 injuries treated with an SHS and 31A2.2, 31A2.3, and 31A3 injuries treated with a short CMN. Total re‐operation rate for extracapsular fractures was reduced from 13 to 7% (p = 0.002) with most of that decrease coming from the unstable intertrochanteric fracture group (17% vs 8%, p <0.001).¹⁸

Resolution of clinical scenario

Related posts:

The Direct Anterior Approach Patient‐Specific Instrumentation in Total Knee Arthroplasty Management of Glenoid Bone Loss Distal Femur Fractures Periprosthetic Fractures: Knee Lisfranc Injuries

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