Total hip arthroplasty (THA) is a highly successful and reliable surgical procedure for restoring function and relieving pain in both traumatic and non-traumatic hip pathologies. As global life expectancy rises, the incidence of femoral neck fractures and demand for THA are also increasing. Displaced femoral neck fractures carry high rates of morbidity and mortality, leading many clinicians to favour THA, especially in active older adults, due to superior functional outcomes over hemi arthroplasty ^{[1,2,3,4,5,6,7]}. Beyond trauma, non-traumatic etiologies – including osteonecrosis, osteoarthritis (OA), and inflammatory arthritis – commonly require arthroplasty, with optimal results reported across diverse patient groups ^[8,9,10,11].

However, direct comparisons of THA outcomes for traumatic versus non-traumatic indications reveal conflicting evidence. Some studies indicate greater intraoperative and postoperative complications, blood loss, and longer hospital stays for trauma cases ^[12,13,14], while others report comparable or even equivalent short-term and long-term outcomes in functional recovery, implant survivorship, and complication rates ^[15,16]. Most comparative data originate from Western cohorts where the non-traumatic cohort is typically older and dominated by primary OA. Indian studies remain sparse, and population-specific differences are underreported. In this demographic, the non-traumatic cohort is often younger and more commonly presents with etiologies, such as osteonecrosis, post-infectious sequelae, or inflammatory arthritis, which differ significantly from primary OA. To our knowledge, no study to date has prospectively evaluated these outcomes in an Eastern Indian population.

This study aims to prospectively evaluate and compare the intraoperative, early post-operative, and 3-month functional outcomes of THA performed for traumatic versus non-traumatic hip pathologies in an Eastern Indian cohort. We aim to provide data to refine patient counselling, surgical planning, and post-operative management strategies in Indian healthcare settings.

Study design and setting

This was a single-centre, prospective, comparative study conducted in the Department of Orthopaedics at the All India Institute of Medical Sciences (AIIMS), Bhubaneswar, India, between January 2021 and December 2022, with Institutional Ethics Committee approval, vide reference number (IEC/AIIMS BBSR/PG Thesis/2020-21/82).

Inclusion and exclusion criteria

Inclusion

Patients aged 30–70 years undergoing primary THA for either traumatic femoral neck fracture (Group A) or non-traumatic etiologies (Group B: Primary OA, avascular necrosis, inflammatory arthritis, post-traumatic arthritis, congenital disorders, or hip fusion).

Exclusion

Acute hip infection, revision arthroplasty, tumor, bilateral THA, unwillingness to provide informed consent, or body mass index >30.

Sample size

The sample size was determined using the two-proportion difference formula, referencing data from Agarwal et al. Assuming a risk difference of 0.16 (proportion of success in Group A = 0.84, Group B = 0.68), with a desired confidence level of 95% and accounting for an anticipated 10% loss to follow-up, the minimum required sample size was calculated to be 24 participants per Group ^[17].

Surgical technique and perioperative care

All procedures were performed by a single senior surgeon under spinal anaesthesia, utilising a standardised modified Hardinge (anterolateral) approach to minimise technical variability.

The approach involved an incision over the greater trochanter, followed by an incision of the tensor fascia lata (TFL). The TFL was retracted anteriorly and the gluteus maximus posteriorly. The gluteus medius was split in line with its fibres, with the incision limited to 5 cm proximal to the greater trochanter to protect the superior gluteal neurovascular bundle. The gluteus minimus and a portion of the vastus lateralis were elevated as a single sleeve from the anterior trochanter. A “T”-shaped capsulotomy was performed to expose the femoral head and neck. The femoral head was dislocated, or in cases of fusion (e.g., ankylosing spondylitis), an in situ neck cut was performed. The acetabulum was sequentially reamed, and uncemented components were implanted after trialing for stability, version, and limb length. Femoral preparation and implantation were followed. Stability was reassessed, and routine closure was performed. All patients received a standardised post-operative protocol, including five days of intravenous antibiotics and multimodal analgesia. Supervised physiotherapy was initiated on post-operative day 2, with appropriate precautions for dislocation. Mobilisation was directed by the chief surgeon based on intraoperative findings and patient stability.

Data collection and outcomes

Data were captured in a structured pro forma. Key endpoints included:

1. Primary outcome: Modified Harris hip score (MHHS) and Visual Analog Scale (VAS) for pain at 3 months post-operatively.
2. Secondary outcomes:

• Intra-operative parameters: Surgical time (incision to closure), estimated blood loss, need for blood transfusion, any additional surgical procedures (e.g., tenotomy, osteotomy), and intra-operative complications (e.g., periprosthetic fracture).
• Early post-operative parameters (within 5 days): Surgical site infection (SSI), drain volume (bleeding), total length of hospital stay, and daily VAS pain scores.
• 3-month follow-up parameters: Clinical assessment for complications (infection, dislocation, limping, implant loosening, periprosthetic fracture), requirement for walking aids, and sit-to-stand time. Radiographs were obtained to assess implant position and fixation.

Statistical analysis

Data were entered into a Microsoft Excel spreadsheet and analysed using the Statistical Package for the Social SciencesStatistics for Windows, Version 25.0 (IBM Corp., Armonk, NY). The Shapiro–Wilk test was used to assess the normality of continuous data. Normally distributed continuous variables (e.g., age, surgical time) were presented as mean ± standard deviation and compared using the independent Student’s t-test. Non-normally distributed or skewed data (e.g., VAS scores, MHHS) were presented as medians (interquartile ranges) and compared using the Mann–Whitney U test. Categorical variables (e.g., gender, complications, need for transfusion) were presented as frequencies (n, %) and compared using the Chi-square test or Fisher’s exact test where cell counts were low. A P < 0.05 was considered statistically significant for all analyses.

Patient demographics and baseline characteristics

A total of 60 patients were screened for eligibility between January 2021 and December 2022. Twelve patients were excluded (unwillingness to participate). The remaining 48 patients were enrolled and allocated, with 24 patients in Group A (traumatic) and 24 in Group B (non-traumatic). The mean age of patients in Group A was 55.17 years, which was significantly greater than in Group B (41.63 years) (P < 0.001). The gender distribution was identical in both groups (16 male, 8 female). Group A consisted entirely of femoral neck fractures. Group B was heterogeneous, comprising osteonecrosis/avascular necrosis in 18 patients, ankylosing spondylitis in 5 patients, and sequelae of Perthes disease in 1 patient.

Intra-operative outcomes

There were no statistically significant differences between the two groups in terms of mean surgical time, mean estimated blood loss, or the proportion of patients requiring blood transfusions (P > 0.05 for all) (Table 1).

Table 1: Intra-operative parameters

Two intra-operative periprosthetic fractures (proximal femur) occurred in Group A (8.3%) during femoral broaching, which were managed with cerclage wiring. No intraoperative fractures occurred in Group B. One patient in Group B required an adductor tenotomy for contracture. This difference in intra-operative complications was not statistically significant (P = 0.488 by Fisher’s exact test).

Early post-operative and 3-month outcomes

No significant differences were observed in early post-operative parameters, including drain output, length of hospital stay, or VAS pain scores at 24 h, 48 h, or 5 days (P > 0.05 for all) (Table 2).

Table 2: Parameters within 5 post-operative days

One case of marginal skin necrosis (non-traumatic Group) was managed conservatively. No deep SSIs were noted in either Group within the 5-day period.

At the 3-month follow-up, no significant difference was found in the primary functional outcomes (Table 3).

Table 3: Functional and clinical outcomes between 2 groups at 3 months post-operative follow-up

The mean MHHS was 65.75 in Group A and 69.96 in Group B (P = 0.11). The median VAS score at 3 months was also comparable (P > 0.05). No instances of revision surgery, dislocation, deep infection, or implant loosening were recorded in either Group at 3 months. There were no significant differences in limping, use of walking aids, sit-to-stand time, or leg length discrepancy.

The principal finding of this prospective study is that at 3 months post-surgery, patients undergoing THA for traumatic and non-traumatic hip pathologies achieve comparable early functional outcomes. This finding supports our initial hypothesis and aligns with the results of Abboud et al. and Lizaur-Utrilla et al., who also found no significant difference in functional outcomes between the fracture and elective cohorts ^[15,16]. Our results, however, contrast with several large registry studies that report poorer outcomes and higher complication rates in trauma patients ^[13,18]. This discrepancy may be multifactorial. Large registry studies often lack the granularity to account for surgical factors (e.g., single-surgeon consistency) or detailed patient-level factors. Furthermore, our study’s short follow-up period may obscure long-term differences. A key finding in our cohort was the non-significant (P = 0.488) but clinically notable trend of intraoperative complications in the trauma group. We observed two (8.3%) periprosthetic fractures in Group A, versus zero in Group B. This is likely attributable to the significant demographic difference we identified: The trauma group was, on average, 13.5 years older than the non-traumatic Group (P < 0.001). This older age is associated with a higher prevalence of osteoporosis, rendering the femur more susceptible to fracture during broaching ^[19]. This finding underscores the importance of meticulous femoral preparation, careful implant sizing, and readiness to deploy cerclage fixation when performing uncemented THA in older fracture patients ^[20,21].

A unique aspect of our study is the composition of the non-traumatic Group. Unlike in Western studies, where Group B would consist almost entirely of primary OA, our non-traumatic cohort was younger and dominated by osteonecrosis (75%) and inflammatory arthritis (21%). This demographic reality in the Eastern Indian population introduces a significant confounding variable. Osteonecrosis and ankylosing spondylitis (AS) are distinct pathologies from OA, with different patient profiles and prognoses. Studies have shown that THA in osteonecrosis patients may have higher rates of revision and complications than in OA patients ^[22], while AS patients may experience more blood loss and functional limitations ^[23]. Therefore, our “non-traumatic” Group is not a homogeneous control, which complicates direct comparison with other studies. The major strength of this study is its prospective, comparative design, which is a rarity on this topic within the Indian population. A uniform surgical approach, single-surgeon technique, and standardised perioperative protocol reduce variability related to surgeon experience, implant selection, and rehabilitation regimens. This study has several important limitations. The follow-up duration of 3 months is sufficient to capture early functional recovery and acute complications, but is inadequate for assessing long-term outcomes, such as aseptic loosening, late infection, or implant survivorship. The “excellent” survivorship found in our study (no loosening or revision) is due to this short duration of follow-up and not indicative of long-term success. As discussed, the non-traumatic group was highly heterogeneous, and the two groups were not matched for age. This baseline demographic difference (age) is a major confounder that likely influenced the intraoperative fracture rate. Small sample size

Although powered to detect a difference in MHHS, our sample size (n = 48) is too small to draw firm conclusions about complication rates. The study is underpowered to detect a statistically significant difference in rare events, such as fractures or dislocations. The lack of a significant difference in complications should be interpreted with caution. This study, to our knowledge, is the first prospective comparison of its kind in an Eastern Indian population. The findings suggest that despite demographic differences and intraoperative challenges, the early functional recovery trajectory is similar for both groups. This information is valuable for clinicians in counselling patients and managing expectations.

THA provides excellent and comparable early functional outcomes and pain relief at 3 months for patients with both traumatic and non-traumatic hip pathologies. In our cohort, the traumatic Group was significantly older and experienced a higher (though not statistically significant) rate of intra-operative periprosthetic fractures, likely related to poorer bone quality. The early functional parity suggests that THA is a reliable procedure for both indications. However, these findings must be interpreted with caution, given the study’s significant limitations, including the short follow-up period, small sample size, and heterogeneous nature of the non-traumatic cohort. Further research with larger, matched cohorts and long-term follow-up is necessary to confirm these results and assess implant survivorship.

THA can be confidently done in both traumatic and non-traumatic hip pathologies. Heightened intraoperative vigilance and careful femur medullary canal preparation are needed in old trauma patients.