Baylor University Medical Center Proceedings July 2017 - 271

DISCUSSION
To our knowledge, no previous studies have speciﬁcally
compared methods of intertrochanteric and pertrochanteric
hip fracture ﬁxation and the associated risk of subsequent contralateral hip fracture. Souder et al (12) recently reported a signiﬁcantly increased risk of subsequent contralateral hip fracture
after treatment of a femoral neck fracture with closed reduction
percutaneous pinning in comparison with hip arthroplasty. The
purpose of this study was to report the rate of contralateral
hip fracture after an initial IT/PT fracture treated with HSSP
compared with CMN. One might expect this study to produce
outcomes similar to those of Souder et al (12), especially with
the large number of patients and a similar database of patients.
However, our results indicated no diﬀerence in the rate of contralateral hip fractures when treating IT/PT proximal femur
fractures with HSSP compared with CMN. Regardless of type
of ﬁxation used in these circumstances, the patient had an 8.9%
chance (with a 95% conﬁdence interval of 7.3 to 10.7) of suffering a subsequent contralateral hip fracture.
We found bisphosphonate use to be associated with having
a subsequent contralateral hip fracture (P = 0.02), but this result
does not hold in a propensity score match analysis. Eighty-four
patients in the HSSP group and 165 patients in the CMN
group were taking bisphosphonates for a diagnosis of osteoporosis. The odds for a second fracture were 1.7 times greater
for patients taking bisphosphonates compared with those not
taking bisphosphonates.
Diabetes mellitus and smoking history did not demonstrate
a statistically signiﬁcant association with subsequent hip fracture
after the index fracture (P = 0.79 and 0.97, respectively). There
were more diabetic patients in the CMN group than in the
HSSP group, but this diﬀerence was not statistically signiﬁcant
(P = 1.0). This may have elevated the rate of contralateral hip
fractures in this group, but our analysis did not validate this
assumption.
Our data indicate that when utilizing appropriate surgical
indications in the setting of AO/OTA 31-A1 and A2 IT/PT
fractures, there was no diﬀerence in the rate of contralateral hip
fractures regardless of method of ﬁxation. A recent literature
review conducted by Kaplan et al (18) recommended ﬁxing
unstable intertrochanteric hip fractures with a CMN due to
evidence that intramedullary devices aid in early mobilization
and return of ambulatory function, presumably by maintaining a better reduction and not allowing the shortening and
decreased oﬀset seen with HSSP ﬁxation (19, 20). Kaplan does
not stand alone, as several other prospective randomized trials
have supported a better preservation of reduction when nails
are used (21-23). The two surgical groups, however, were not
entirely comparable; 31-A1 fractures were treated more often
with HSSP, while 31-A2 fractures were treated more often with
CMN. Our results do not suggest that highly unstable fractures
treated with either HSSP or CMN will have a similar contralateral fracture rate. Even when CMN nails are used to ﬁx more
complex and potentially unstable fracture patterns, a similar
rate of contralateral fracture is seen compared with HSSP when
utilized in less severe fracture patterns.
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There was no diﬀerence in the distribution of age in patients
that had a second fracture. Current reports also indicate that the
older the patients, the more likely they are to sustain both an index fracture and a subsequent hip fracture (24, 25). Overall, the
median age of our cohort at the time of their initial hip fracture
was 82.4 years for both the HSSP and CMN group; the median
age of the cohort that sustained a contralateral fracture at the
time of their initial hip fracture was 81.8 years. The average age
of a contralateral fracture in 103 patients was 83.6 years. These
data are in line with current literature that reports an average
age of 77 ± 6.7 years and 80 ± 6.4 years at the time of initial
and second fracture, respectively (11).
Both treatment groups experienced a similar median
length of time until they suﬀered a contralateral hip fracture
(HSSP was 9.9 years and CMN was 6.8 years; P = 0.62). A literature review found a wide range of data with intervals from
initial to subsequent fracture between 2 and 7+ years (11,
26). Souder et al (12) noted a 21.2- to 24.9-month interval
between an initial femoral neck fracture and the subsequent
hip fracture. More research into deﬁning a tighter interval
(and possibly exploring reasons for such varied intervals) may
be warranted.
The limitations of our study include its retrospective nature
and surgeon bias. All retrospective studies are limited by their
ability to retrieve data and control variables. Furthermore, the
sample size is often diminished due to missing data points.
Surgeon bias such as varied experience in interpretation of radiographs and familiarity with surgical techniques also likely
aﬀected how the fractures were classiﬁed and which implant
the patient received. The scope of this study did not include a
number of variables, which potentially aﬀected our ﬁndings. A
prospective study would most likely be required to get accurate
data on mental status, ambulatory status, degree of osteoporosis,
and current control of diabetes throughout the period of study,
all of which would lead to more accurate data and a better
understanding of confounding variables.
To summarize, our data showed no diﬀerence in the rates of
contralateral hip fracture when comparing HSSP with CMN.
Our results did suggest that patient-related variables such as
bisphosphonate use are associated with an increase in the rate of
contralateral hip fracture after initial IT/PT fracture; however,
these are complex topics and further research would be needed
to deﬁnitively make a statement on these variables. The factors
of implant choice (HSSP vs CMN) and smoking history did
not appear to aﬀect the rate of contralateral hip fracture after
IT/PT fracture.
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3. Hannan EL, Magaziner J, Wang JJ, Eastwood EA, Silberzweig SB, Gilbert M, Morrison RS, McLaughlin MA, Orosz GM, Siu AL. Mortality
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Treatment of pertrochanteric hip fractures

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Table of Contents for the Digital Edition of Baylor University Medical Center Proceedings July 2017