Study population
This present study comprised a prospectively documented cohort including 2 052 consecutive hip fracture patients aged ≥ 65 who sustained their first hip fracture between September 2007 and January 2019 in the Hospital District of Southern Ostrobothnia, Finland. Basically, all patients who suffer from a hip fracture or surgical complication after treatment of a hip fracture inside the referral area are admitted and operated at Seinäjoki Central Hospital [17]. Patients who had a pathological or periprosthetic hip fracture were excluded from the study.
The target time for the follow-up visit was 4 months after the fracture, but due to the waiting list situation and patient related factors, the appointment time was realized 4 to 6 months after the fracture. Before the follow-up visit, 407 patients (20%) had died. Of those patients who were still alive, 1331 patients (81%) with the necessary documentation of variables attended the follow-up visit and were included in the study (Fig. 1).
Flow chart of study population
Data collection
In 2007, a program for orthogeriatric care was launched along with a prospective data collection [17]. Patient characteristics or clinical tests were collected on admission, during hospitalization, by phone interview and 4 to 6 months after the fracture at the geriatric outpatient clinic by a multidisciplinary team. If a patient was incapable of providing information due to their health condition or cognitive problems, family members, close friends, or nurses from a health care facility were used to obtain the data. During the study period, predefined inquiries modified from British hip fracture register were used to obtain as accurate data as possible [18]. Data has been collected over several years. More measures of physical performance have been added to the outpatient visit during the data collection and therefore reports with different performance tests were available for a varying number of patients. Information on changes in mobility was collected by phone interviews 4 months after the fracture. Follow-up visits at the geriatric outpatient clinic with a comprehensive geriatric assessment (CGA) was carried out 4 to 6 months after hip fracture by a multidisciplinary team [19]. A physiotherapist´s examination including the physical performance tests preceded the geriatric assessment. Both patient and his or her next of kin or caregiver were invited.
On admission patients or their representatives were asked to give their informed consent for the data collection. The study design was approved by the Ethics Committee of the Hospital District of South Ostrobothnia. The Strobe reporting guidelines were followed.
Fracture types, surgical methods, and baseline characteristics
Fracture diagnoses of the upper femur set by the orthopaedic and trauma surgeon were derived from the electronic patient files and were categorized as femoral neck fracture, pertrochanteric fracture and subtrochanteric fracture.
Among all patients with a femoral neck fracture, 83% were treated with hemiarthroplasty (HA), 13% with total hip arthroplasty (THA) and 4% with internal fixation. Physiologically exceptionally active and mobile femoral neck fracture patients were treated with total hip arthroplasty. The surgeon on duty decided whether to use a lateral (modified Hardinge) or posterior approach for the repair to the posterior capsule and external rotators in both HA and THA. The implant used in the HA was uncemented or cemented modular monopolar prosthesis. Internal fixation was used only in Garden I and II fractures with good bone quality. However, when a patient had severe osteoporosis or co-morbidities adversely affecting bone healing, HA was used even in Garden II fractures. Stable pertrochanteric fractures were treated with a short intramedullary nail with a sliding screw, whereas unstable pertrochanteric and subtrochanteric fractures were treated with a long intramedullary nail with a sliding screw.
Nutritional status was measured using the Mini-Nutritional Assessment-Short Form (MNA-SF), which is a short screening tool for nutritional status with documented clinical relevance and validation in older populations [20]. The MNA-SF was categorized into three groups: normal [12,13,14], at risk of malnutrition [8,9,10,11] and malnourished (0–7). Living arrangements were categorized as living at home, home with home care, assisted care facility and institution. The number of regularly used medications on admission and American Association of Anaesthesiologists (ASA) scores were used to assess medical co-morbidities [21, 22]. The ASA was categorized into three groups: 1–2,3 and 4–5. Diagnosis of cognitive disorder (yes or no) was registered at the time of fracture. A cognitive disorder known pre-fracture was defined as a clinical diagnosis of cognitive disorder diagnosed by a specialist in geriatric medicine or neurology. The diagnosis was confirmed from the patient records. Mobility level before hip fracture was defined on a basis of survey like questions modified from those originally included in the data collection of the British National Hip Fracture Database. Based on these questions of walking ability, mobility level was graded into 4 groups: 1. Unassisted outdoors, 2. Assisted outdoors, unassisted indoors 3. Assisted indoors and 4. Unable to walk. Mobility level was evaluated by similar questions at baseline and follow-up phone interview at 4 months post-fracture. The need for a mobility aid was also registered. All the baseline variables with their categorizations are listed in Table 1.
Physical performance and functional ability
Primary outcome variables were grip strength, Timed Up and Go -test (TUG), Elderly Mobility Scale (EMS), Basic Activities of Daily Living (BADL), Instrumental Activities of Daily Living (IADL) and mobility change. Physical performance was measured with grip strength, TUG and EMS whereas IADL and BADL describe functional ability.
A physiotherapist´s examination preceding the geriatric outpatient clinic visit included a hand grip test, a TUG and an EMS. The hand grip strength is an easy and inexpensive method to assess muscle strength. Grip strength correlates moderately with strength in other body parts and was measured using a Jamar handheld dynamometer. Impaired grip strength for women was considered to be < 16 kg and for men < 27 kg. The definition for impaired grip strength and impaired TUG were chosen according to the 2019 update on the European Working group on Sarcopenia in Older People (EWGSOP2) [23, 24].
The TUG test is a modified, timed version of the “Get-Up and Go” test [25]. The test requires patients to stand up from a chair, walk 3-m distance, turn around, return, and sit down again. Timed up and go test measures physical performance and predicts falls and has been used to identify frail older individuals [26]. We categorized normal cut off point as TUG ≥ 20 s [23].
The EMS is a standardized validated scale for assessing the mobility of frail older people[27] EMS is also easy to perform on patients with cognitive impairment and mainly measures functional mobility [28]. Patients who score 14 or more are able to perform the mobility manoeuvres alone and safely and this group of patients is independent in basic ADL [27] The movements of the EMS test include lying to sitting, sitting to lying, sitting to standing, standing, gait, walking speed and functional reach [27]. Based on the practical evaluation, each of the 7 functional tests is awarded a number of points, varying from 0 to 4 and the points are added up. EMS for frail people was categorized as normal (14-20) or abnormal (0–13).
The outcome variable of mobility change was defined as declined mobility from baseline to the 4-months phone interview carried out by the geriatric nurse. The same questions for mobility level, as described in the baseline variables, were used at both time points. Decline in mobility was defined as having more assisted vs. same or less assisted mobility level at follow-up compared to the pre-fracture mobility level.
BADL describes the tasks of everyday life including eating, dressing, getting into or out of a bed or chair, bathing, ability to control movements of the bowel and bladder and using the toilet. Each activity is awarded by one point and points are added up. BADL was categorized as no difficulties (score 6/6), or difficulty in at least one activity [29]. IADL consist of managing communication such as telephone and mail, preparing meals, managing finances, managing transportation, shopping, managing medication, doing laundry, and keeping up home maintenance. IADL was categorized as no difficulties (score 8/8), and difficulties at least in one [30].
Statistical analyses
The baseline characteristics before fracture and geriatric post fracture assessment after hip fracture were described according to three fracture types as number of patients and percentages of categorical variables. Statistical differences between the groups were tested using Pearson´s chi-square test or Fisher-Freeman-Halton exact test, if appropriate.
Univariable and multivariable adjusted logistic regression analyses was used to examine the association of different hip fracture types for physical performance tests, mobility change and functional ability. The results of patients with pertrochanteric fractures and subtrochanteric fractures were compared with the results of patients with femoral neck fractures. The multivariable analyses were adjusted for gender, age, pre-fracture living arrangements, ASA scores, a known cognitive disorder, mobility and the need for mobility aid. The results of logistic regression analyses are given as odds ratios (OR) with 95% confidence intervals (CIs).
IBM SPSS statistics version 28.0 (SPSS Inc. Chicago, Illinois, USA) was used for statistical analyses. Two-sided p-values under 0.05 were considered statistically significant.
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