Mobility following femoral neck fracture surgery: Does surgical treatment affect outcome?

1 Introduction

Hip fracture in patients over age 65 years is associated with mortality and loss of independence, as well as imposing a significant cost on the health care system [1]. In 2019, 3701 patients were admitted to 16 acute hospitals across Ireland with hip fracture, accounting for 72314 acute bed days that year [2]. Hip fractures are categorised based on fracture location (i.e., femoral neck, intertrochanteric and subtrochanteric fractures), with femoral neck fractures accounting for approximately 45% of all hip fractures in the elderly [3]. Arthroplasty, either total or hemi, is usually performed in older patients with displaced neck of femur (NOF) fractures, with a total joint arthroplasty the preferred choice for those who are mobile outdoors, with no cognitive impairment and who are medically fit for surgery [4]. Internal fixation can be performed for non-displaced hip fractures, especially in younger patients, and those with per trochanteric or subtrochanteric fracture [5].

A systematic review of four studies comparing the outcomes of 579 elderly patients with non-displaced and minimally displaced NOF fractures, treated with internal fixation versus arthroplasty, found that treatment with hemi-arthroplasty may reduce the relative risk of reoperation by 70% when compared with internal fixation [6].

This finding was supported by two further studies (comprising 78 and 219 patients respectively) comparing outcomes between arthroplasties and internal fixation, which found that those receiving a hemiarthroplasty showed fewer post-op complications, lower re-operation rates and better functional outcomes in the early post-op phase [7, 8]. Bartels et al found higher reporting of post-operative pain in those treated with internal fixation, compared with arthroplasty, however the exact reasoning for this was not outlined [9].

Weight bearing status postoperatively can vary in this patient population depending on surgery performed. Those treated with an internal fixation occasionally require periods of non-weight bearing, toe-touch weight bearing or partial weight bearing to allow appropriate bone union, whereas patients treated with arthroplasty can generally bear weight immediately post-surgery.

The physiotherapy department in our unit provides a seven-day orthopaedic service and aims to ensure that all patients post hip surgery are assessed and mobilised (where possible) within 24 hours of surgery. This is in keeping with the Irish Hip Fracture Database (IHFD) recommendations which sets out standards to promote optimal patient care [1].

The aim of this study was to evaluate patient rehabilitation in the acute post-operative stage, and to establish whether rate of patient recovery (functional restoration and mobility) in the post-operative period, depending on the surgery type received.

This hypothesis was based on therapist experience and research highlighting better functional outcome for hip fracture patients receiving arthroplasty [7, 8]. The study ultimately aimed to identify potential differences in mobility outcomes between the groups which would help to identify patients, early in the post-operative period, who may require further rehabilitation prior to discharge home to optimise functional restoration.

2 Methods

A prospective audit was conducted on all patients admitted to the orthopaedic ward with a hip fracture over a twelve-month period, from October 2019– October 2020. This cohort included those with NOF fractures, intertrochanteric fractures and subtrochanteric fractures. The audit was completed by the treating physiotherapist/s on the ward. Patients who were immobile pre-fracture, unable to mobilise independently or who received treatment other than the surgeries identified were excluded. Complete data were collected on 134 patients over this 12-month period.

An audit tool was developed to collect patient demographics, specifically: age, fracture type, mechanism of injury, surgery type, surgery date, time from admission to surgery, weight bearing status post operatively, New Mobility Score (NMS) [10], day of initial Timed Up and Go (TUG) [11] completion, initial TUG Score, discharge TUG score, Cumulative Ambulatory Score (CAS) score on day 1 post-operatively, CAS score on discharge, discharge destination and in-patient length of stay. The CAS is a valid tool for evaluating an orthopaedic patient’s basic mobility (getting in and out of bed, sit to stand from a chair and walking), this outcome measure is recommended for use on patients port hip fracture [11]. The CAS was measured on day one post operatively and again on discharge. Discharge CAS sores are considered a good predictors of discharge destinations in the geriatric population [11]. The NMS was completed on first patient assessment postoperatively to provide a baseline measure of pre-fracture mobility level. The NMS scale is a 9-point scale scoring a patient’s ability to perform: indoor mobility, outdoor mobility and shopping. This tool has been shown to be a reliable predictor of inpatient rehabilitation potential and likelihood of regaining independence and of discharge directly home [12].

The TUG was used to assess mobility during inpatient stay and was completed as early as possible post-op and again on discharge.

This tool is used to measure, in seconds, the time taken to independently stand up from a standard armchair, walk a distance of 3 meters, turn, walk back to the chair and sit down. The time taken to complete the task is strongly correlated to level of functional mobility [13]. TUG at discharge has been shown to be a significant predictor of falls within 6 months after hip fracture and a sensitive measure for identifying people with hip fracture at risk for new future falls [14].

Initial TUG was completed on the first day that the patient was able to stand independently and mobilise 6 meters irrespective of the walking aid required.

This was then repeated when the patient was either discharged from hospital or when the patient was discharged from physiotherapy – if discharge was delayed for medical/social reasons.

In-service training sessions are bi-annually provided to all staff who work on the weekend physiotherapy service to ensure that the appropriate outcome measures and paperwork are completed in a timely manner. No changes were made to the rehabilitation given to patients during this time compared with the normal practice of the service.

Those patients managed prior to March 2020 received both individual therapy sessions and group exercise classes, whilst patients managed after March 2020 received only individual sessions due to the restrictions surrounding group classes due to the Covid-19 pandemic. The components of both the group-based rehabilitation sessions and the individual rehabilitation sessions were the same, with the exercise provided based on those recommended by the Royal Osteoporosis Society’s ‘Steady, Strong, Straight’ model [15]. This approach from the Royal Osteoporosis Society recommends delivering a programme of strengthening exercises, as well as postural and balance re-education 2-3 days per week to promote bone strength, reduce the risk of falls, and manage symptoms associated with osteoporosis.

The classes delivered at our site included both upper and lower limb strengthening exercises using resistance bands, as well as balance rehabilitation for all those patients who were not under infection control restrictions, and were cognitively able to participate in same and information leaflets were provided to all patients on managing osteoporosis. Both the arthroplasty and the internal fixation groups received the same duration and frequency of physiotherapy (goal of 3×30 min sessions per week).

3 Results

In total, data were collected on 134 patients, 89 of whom had NOF fractures. Of these, 60 (67%) were females and 20 (23%) were males, with a media age of 79 years (ranging from 50–96 years). Baseline characteristics of the sample are shown in Table 1.

The ORIF group were younger in age than the arthroplasty group (mean age 71.4 years vs. 79.3 years) (p = 0.0027). Prior to admission to the orthopaedic ward, 82 were living at home, six were living in a nursing home, and one was transferred from another inpatient ward. On discharge from the orthopaedic ward, 37 were discharged home, 40 were transferred to another facility for rehabilitation, 11 were discharged to nursing homes, and one passed away from cardiac complications post-operatively. Eighty-six of the fractures were sustained from a fall/trauma, with only three occurring without any history of trauma.

Of the 89 NOF fractures, 65 received a hemi-arthroplasty, four received total hip replacement (THR), nine received a dynamic hip screw (DHS) and 11 received an intramedullary nail. Depending on the surgical intervention employed the weight bearing status varied slightly between patients (Table 2).

There was no significant difference in the Day 1 post-op function between the two groups, the ORIF group scored a CAS of 3.1 while the arthroplasty group scored 2.5 (p = 0.095) indicating a higher level of function day 1 post operatively in the ORIF group.

Of the arthroplasty group, 54/69 (78%) were able to complete a TUG prior to discharge compared to 17/20 (85%) of the ORIF group. The inability of 22% of the arthroplasty group and 15% of the ORIF group to complete a TUG on discharge meant that final data could only be analyzed, and subsequent conclusions drawn, on those who could mobilise the 6 meters of a TUG. On average those able to complete a TUG in arthroplasty group took longer (median of 4.9 days) (range day 1 – 16) to complete their initial TUG post-operatively, versus those in the ORIF group (median 4.3 days) (range day 2 – 13). The mean time to complete the initial TUG was 87.8 seconds in arthroplasty and 74.7 seconds in ORIF group, however there were a number of outliers which may skew this data; therefore, the median time was calculated at 76.5 seconds (arthroplasty) and 63 seconds (ORIF).

By discharge the time taken to complete this distance had reduced in both groups with the arthroplasty group completing the TUG in a median of 40 seconds and the ORIF group completing the TUG in a median of 42.5 seconds, indicating an insignificant difference between the two groups (Value 0.85) (Table 3).

Improvements in both the TUG and CAS outcome measures was observed in both groups. From the data collected, it is evident that all patients made improvements with physiotherapy intervention during their acute admission. Such improvements are in keeping with the well documented benefits of early physio intervention post hip surgery, specifically mobilization, most recently reported in a study published by the UK national hip fracture database, who reported a 2-fold increase in the likelihood of discharge within 30 days post-operatively in those who were mobilized early post-surgical intervention [19].

This audit highlighted that a similar proportion in both surgery groups remained at risk of falls at the time of discharge from the acute hospital (≥90%). This finding was not surprising as much of the literature on patient outcomes post hip fracture highlights the potential negative impact of a hip fracture itself irrespective of surgery; specifically, that most of those who survive surgery do not regain their pre-injury level of function and 30% of survivors will lose their independence [18].

The presence of an ongoing falls risk post-operatively supports the need for the development of future rehabilitation pathways and services for this frail, older adult population. The National Clinical Programme for Older People (NCPOP) and the Integrated Care Programme for Older Persons (ICPOP), set out a 10-Step integrated care framework to address such needs in the aging Irish population; it was recommended that each hospital should have access to onsite and offsite rehabilitation beds, and that the rehab delivered at these sites structured to best suit the older population [17].

These audit results also echo the findings of a meta-analysis published in 2012 which demonstrated the benefits of extended rehabilitation, beyond the acute post-operative stage as a minimum, for community dwelling individuals after hip fracture surgery [16].

It was reported from this audit that a greater number 318 of the ORIF group were discharged directly home 319 (55% vs 38%) while the majority of the arthroplasty 320 group required further in-patient rehabilitation (Table 4).

Further in-patient rehabilitation was deemed necessary when a patient was not at a functional level to return home safely. The functional level required for safe return home was established based on the patients’ pre fracture mobility status, as reported using the NMS and by liaising with the patient and their family to establish what they felt functionally was required for safe return home.

The increased need for rehabilitation in the arthroplasty group may be explained by the older age profile of this cohort; while data were not collected on patient co-morbidities, the literature would suggest that most hip fracture patients are older, frailer adults and usually present at least 1-2 comorbidities resulting in them being more predisposed to clinical complications, and increased mortality [20].

It should be noted that 16/37 patients who were discharged directly home were referred to the Community Intervention Team or Primary Care Team for further rehabilitation in their own home, which is not recorded in the discharge destination results presented in Table 1 as their discharge destination at the time of data collection was recorded as home.

5 Conclusion

In conclusion this study presents results indicating that irrespective of surgical intervention (arthroplasty or IR) there is little difference in patient outcomes in the post-operative period.

That while the LOS may be less for the IF group it should be noted that this may be attributed to the fact they are a younger cohort.

That greater numbers of patients sustaining hip fractures are female and the greater numbers of patients receive arthroplasties versus internal fixation surgery.

Lastly, this audit presents that irrespective of the surgical intervention received, more than 90% of reviewed hip fracture patients were still a falls risk at the time of discharge from the acute setting thus emphasizing the need for ongoing rehabilitation beyond the acute phase.