Study design and participants
Th retrospective study enrolled 229 patients aged 65 years or older presenting DRF admitted to an acute care hospital between October 2014 and December 2018 who underwent surgery and follow-up for at least 1 year after surgery. Patients were retrospectively identified via a search of the surgical database at our two affiliated hospitals. Demographic and postoperative clinical course information was extracted from each patient’s electronic medical record. Patients with neurological/cognitive impairment, multiple fractures, death, and missing data including bone density that could not be accurately measured after spine surgery were excluded. Ethical approval was obtained from each hospital’s ethics board. Patient informed consent was not required due to the retrospective design of the study.
Surgical treatment and rehabilitation
All patients were treated with internal fixation using a volar locking plate (ACU-LOC plate, ACUMED, LLC., USA, n = 88 cases; Anatomic Volar Plate System. Depuy Synthes, Johnson- Johnson. Co., USA, n = 75 cases; Stellar2, HOYA Technosurgical Co., Japan, n = 42 cases, and APUTUS 2.5, Medical engineering system Co., Japan, n = 24 cases). A standard volar approach was used to expose the fracture side. The fracture was approached from the radial side of the flexor carpi radialis, and the quadrate pronator muscle was incised to reduce the fracture. If the fracture was unstable, it was reduced with Kirschner wire. Following the surgery, all patients were casted for 3–7 days depending on the stability of the fracture site. In postoperative rehabilitation, finger excursion training was started from the day after the operation. Active and passive training of the wrist joint with one-to-one guidance were started after cast removal.
Measurements
Information collected for all patients included age, sex, body mass index (BMI), total number of drugs administered on admission, number and type of potentially inappropriate medications (PIMs) on admission, bone mineral density (as a percentage of the mean values for young adults), fracture type, comorbidity severity (Charlson Comorbidity Index, CCI), nutritional status (Geriatric Nutritional Risk Index, GNRI), wrist function criteria (Mayo Wrist Score), Barthel Index (BI), presence of subsequent falls, and follow-up periods after surgery.
Osteoporosis was defined as a T-score less than and equal to − 2.5 SD in the lumber vertebrae (L2–4). The AO classification was used to describe the DRF type. This classification system is commonly used for the radiographic classification of DRF and includes three types: A, B, and C. A is an extra-articular fracture, B is an intra-articular fracture, and C is an intra-articular complete fracture.
Comorbidity was assessed using the CCI [17]. The CCI is an indicator of multi-disease comorbidities and includes diabetes with chronic complications, heart failure, kidney disease, liver disease, chronic lung disease, dementia, hemiplegia or paraplegia, malignancy, and AIDS/HIV. The CCI uses a weighted score for each comorbidity, with higher numbers indicating a greater number of comorbidities and greater risk of mortality.
GNRI was calculated using the formula proposed by Bouillanne et al [18]:
14.89 × serum albumin (g/dL) + {41.7 x (current/ideal body weight)}.
Individuals with GNRI less than 92 were assigned to the malnutrition group, and those with GNRI more than 92 were assigned to the normal group with mild or no risk of malnutrition.
ADL were evaluated by the BI. The BI is an assessment of 10 items: eating, moving, dressing, toilet movement, bathing, walking, going up and down stairs, changing clothes, defecation, and urination. Each item is scored as 0: unable to complete; 1: needs help; or 2: independent, and the total score is multiplied by 20, for a maximum score of 100. ADL was assessed before surgery and at the final follow-up. BI efficacy was defined by the BI at the end of follow-up minus the preoperative BI. The Mayo wrist score was used for wrist function evaluation. The scale includes scores for pain, functional status, range of motion, and grip strength, with a total score of 0 to 100. The higher the score, the better the function.
Subsequent falls were defined as falls caused by carelessness and did not include falls caused by traffic accidents, brain injuries, or diseases such as epilepsy.
Outcomes
The primary outcome was BI gain, which was defined as the difference in the total BI at one year after surgery from that on admission. The secondary outcome was subsequent falls during follow up periods.
Statistical analysis
The subjects were divided into two groups: the malnutrition group and the normal group. The unpaired t-test, Mann-Whitney's U-test, and χ2 test were used for comparison between the two groups, depending on variables and normality. Spearman’s rank correlation was used for univariate analysis of BI at final evaluation. Logistic regression analysis was also performed to determine whether the dependent variable was the presence or absence of a subsequent fall. As the number in the malnutrition group was small, the number of variables included in the logistic model had to be reduced. Propensity scores were calculated by logistic regression analysis including age, sex, comorbidity index, number of drugs, and fracture type as explanatory variables. All analyses were performed using IBM SPSS Statics version 25 (IBM Corporation; Armonk, NY, USA). A P-value less than 0.05 was considered statistically significant.