Diaphyseal fractures of the humerus represent an important category of upper limb injuries, accounting for approximately 1–3% of all fractures and nearly 20% of humeral fractures encountered in orthopedic practice [1]. These fractures exhibit a characteristic bimodal distribution, affecting young adults through high-energy mechanisms—most commonly road traffic accidents—and elderly individuals through low-energy falls associated with osteoporosis and poor bone quality [2]. The unique anatomical characteristics of the humeral shaft, particularly its close relationship to the radial nerve spiraling around the bone, contribute to the clinical significance and complexity of diagnosing and managing these fractures. Radial nerve palsy has been reported in 2–17% of cases, either at presentation or following surgical intervention [3]. Historically, non-operative management with functional bracing, popularized by Sarmiento, has been widely accepted due to its high union rates, low cost, and minimal invasiveness [4]. Functional bracing allows controlled micromotion at the fracture site, promoting callus formation while preserving shoulder and elbow mobility. Despite these advantages, conservative treatment poses limitations such as prolonged immobilization, poor cosmetic outcomes, malunion, and delayed functional recovery—particularly in obese patients, those with segmental or comminuted fractures, or polytrauma cases where early mobilization is essential [5]. Over the past two decades, advances in implant design and surgical techniques have shifted clinical practice in favour of operative management for humeral shaft fractures. Among various surgical options, intramedullary interlocking nailing has emerged as a preferred modality in many centers owing to its minimally invasive approach, less soft tissue damage and ability to preserve periosteal blood supply [6]. Nailing provides stable fixation with reduced soft-tissue dissection, shorter operative times, and lower infection rates when compared with plate osteosynthesis. These attributes make it particularly advantageous in polytrauma patients, open fractures, pathological fractures, and fractures with significant comminution. However, intramedullary nailing is not without controversy. Concerns regarding shoulder impingement, rotator cuff violation, proximal nail migration, and variable functional outcomes continue to generate debate among orthopedic surgeons [7]. Comparative studies have shown mixed results, with some reporting equivalent union rates between plating and nailing, while others note a higher incidence of shoulder-related complaints in patients treated with antegrade nailing [8]. Given these conflicting findings, there is a continued need for region-specific clinical evidence to support treatment decision-making. In India, where road-traffic-related trauma is rapidly increasing, government hospitals often serve a large, diverse patient population with differing socio-economic backgrounds, injury profiles, and follow-up compliance. Despite the widespread use of intramedullary nailing for humeral shaft fractures, there is a paucity of data from government-sector healthcare facilities, where resource availability and patient demographics differ from tertiary private centers. This retrospective study, conducted at Government Medical College & Hospital, Washim, evaluates 50 cases of diaphyseal humerus fractures managed with antegrade intramedullary interlocking nailing, using hospital records from a three-year study duration (March 2021 to February 2024). The objective is to assess union rates, functional recovery, complication patterns, and early loss to follow-up, generating clinically relevant and locally applicable data. By analyzing outcomes in a real-world government hospital environment, this study aims to strengthen the evidence base guiding orthopedic surgeons in choosing optimal management strategies for humeral shaft fractures.

This retrospective observational study was conducted in the Department of Orthopedics at Government Medical College & Hospital, Washim, covering a three-year period from March 2021 to February 2024. Hospital records from a five-year archive were reviewed to identify a total of 50 patients diagnosed with diaphyseal fractures of the humerus who underwent antegrade intramedullary interlocking nailing as the primary method of surgical fixation. Patients aged 18 years and above, with complete preoperative, intraoperative, and postoperative documentation, including radiographic records, were included. Exclusion criteria comprised pathological fractures, fractures requiring additional fixation (segmental fractures involving other long bones), associated vascular injuries necessitating emergency repair, and cases with incomplete data or inadequate follow-up information. Data were extracted from operative registers, inpatient files, follow-up outpatient department documentation, and radiographic archives. Variables recorded included age, sex, mechanism of injury, side involved, and fracture pattern classified using the AO/OTA system. Operative details such as the surgical approach (antegrade), type and diameter of the interlocking nail used, number of locking screws applied, operative time, and intraoperative complications were documented. Postoperative outcomes were assessed based on follow-up records. Radiological union was evaluated from documented X-rays, with union defined as the presence of bridging callus across at least three of four cortices in orthogonal views. The time to union was categorized as: • Normal union: ≤16 weeks • Delayed union: 16–24 weeks • Non-union: >24 weeks Functional assessment was based on the documented shoulder and elbow range of motion, ability to perform daily activities, and overall limb use as recorded by the treating orthopedic surgeon. Functional outcomes were categorized qualitatively as good, fair, or poor according to recovery of motion and documented patient satisfaction. Complications such as radial nerve palsy, superficial or deep infection, shoulder impingement, delayed or non-union, and implant-related issues (locking screw loosening or nail migration) were identified and recorded. Cases that prematurely discontinued follow-up—due to postoperative complications, persistent pain, or inability to return for review—were classified as loss to follow-up, and their available clinical details were noted separately. All extracted data were entered into Microsoft Excel and analyzed using SPSS version 26. Descriptive statistics were used to calculate frequencies, percentages, means, and standard deviations. Comparative analyses between fracture patterns and outcomes were performed using the Chi-square test, and a p-value < 0.05was considered statistically significant. Institutional permission for data collection was obtained prior to commencement of the study, and confidentiality of patient records was maintained throughout the research process.

A total of 50 patients with diaphyseal fractures of the humerus who underwent intramedullary interlocking nailing were included in this retrospective analysis. Of these, 47 patients (94%) completed follow-up, while 3 patients (6%) were lost to follow-up due to inability to return for review because of socioeconomic constraints. The mean age of the cohort was 43.8 years (range 18–74 years), with a male predominance (62%), reflecting the high incidence of trauma among the active working population. The right humerus was more commonly affected (56%) than the left (44%). Road traffic accidents constituted the most common mechanism of injury (60%), followed by falls (36%) and assault or other causes (4%). Based on the AO/OTA classification, Type 12-A fractures were the most frequent (46%), followed by 12-B (34%) and 12-C (20%). The antegrade approach was used in all cases. The mean operative time was 71 ± 14 minutes, with minimal intraoperative complications documented. Among the 47 patients with adequate follow-up, the average time to radiological union was 15.2 weeks. Normal union (≤16 weeks) occurred in 36 patients (76.6%), delayed union (16–24 weeks) in 7 patients (14.9%), and non-union (>24 weeks) in 4 patients (8.5%). Two of the non-union cases required secondary intervention, while the remaining cases showed slow progression toward union with prolonged immobilization and physiotherapy. Functional outcomes based on documented follow-up assessments showed that 40 patients (85.1%) achieved good to excellent functional recovery with satisfactory shoulder and elbow motion. Five patients (10.6%) had fair outcomes, mostly due to postoperative stiffness or noncompliance with physiotherapy. Two patients (4.3%) demonstrated poor functional outcomes, both associated with non-union and persistent pain. Postoperative complications included shoulder impingement in 6 patients (12.8%), superficial infection in 4 patients (8.5%), and radial nerve palsy in 3 patients (6.4%). All cases of radial nerve palsy were neuropraxias, which recovered spontaneously within 4–5 months. Implant-related issues such as locking screw loosening were encountered in 2 cases (4.3%). The 3 patients did not return for follow-up. Overall, intramedullary interlocking nailing demonstrated high union rates, satisfactory functional recovery, and an acceptable complication profile in the management of diaphyseal humerus fractures in a government hospital setting. Table 1: Demographic and Injury Profile of Patients (n = 50) Parameter Category Frequency Percentage (%) Age (years) 18–30 13 26.0 31–50 22 44.0 >50 15 30.0 Sex Male 31 62.0 Female 19 38.0 Side Involved Right 28 56.0 Left 22 44.0 Mode of Injury Road Traffic Accident 30 60.0 Fall 18 36.0 Others 2 4.0 Follow-up Status Completed 47 94.0 Lost to Follow-up 3 6.0 Interpretation: Most patients were males aged 31–50 years, with road traffic accident being the predominant cause. Three patients did not complete follow-up. Table 2: Fracture Pattern and Operative Details (n = 50) Parameter Category Frequency Percentage (%) AO/OTA Classification Type 12-A 23 46.0 Type 12-B 17 34.0 Type 12-C 10 20.0 Operative Time Mean ± SD 71 ± 14 minutes — Interpretation: Simple fractures (Type 12-A) were most common, and antegrade nailing was the predominant surgical method. Table 3: Union Time, Functional Outcome and Complications (n = 47) (Excluding 3 lost to follow-up) Outcome Parameter Category Frequency Percentage (%) Time to Radiological Union ≤16 weeks (Normal) 36 76.6 16–24 weeks (Delayed) 7 14.9 >24 weeks (Non-Union) 4 8.5 Functional Outcome Good–Excellent 40 85.1 Fair 5 10.6 Poor 2 4.3 Complications Shoulder Impingement 6 12.8 Superficial Infection 4 8.5 Radial Nerve Palsy 3 6.4 Implant-related Issues 2 4.3 Interpretation: Majority achieved union within 16 weeks and had good functional outcomes. Complication rates were acceptable. Table 4: Test of Significance – Association Between AO Type and Outcome Outcome Variable 12-A (n=23) 12-B (n=17) 12-C (n=10) Test Used p-Value Significance Normal Union (≤16 weeks) 20 (87.0%) 12 (70.6%) 4 (40.0%) Chi-Square 0.032 Significant Delayed + Non-Union 3 (13.0%) 5 (29.4%) 6 (60.0%) Chi-Square 0.032 Significant Good–Excellent Outcome 21 (91.3%) 13 (76.5%) 6 (60.0%) Chi-Square 0.041 Significant Complications (All) 4 (17.4%) 5 (29.4%) 6 (60.0%) Chi-Square 0.056 Not Significant Interpretation: More complex fractures (12-C) showed significantly higher delayed/non-union and lower functional recovery. Figure 1: Distribution of AO/ OTA Fracture Types (%) Figure 2: Post- Operative Complications (%)

The present retrospective study highlights that intramedullary interlocking nailing remains an effective and dependable modality for the management of diaphyseal humerus fractures, producing favourable union rates and functional recovery. The demographic pattern of this study—with a mean age of 43.8 years and a clear male predominance—mirrors the trauma epidemiology described by Ekholm et al., who reported similar age and sex distributions in humeral shaft fractures [1]. The predominance of high-energy road-traffic injuries in our study also aligns with earlier observations by Tytherleigh-Strong et al. [2]. In terms of fracture characteristics, AO/OTA Type 12-A fractures were the most frequently encountered pattern, comparable to the findings of Lin and Hou, who reported a similar predominance of simple fracture configurations [7]. The antegrade approach was used in all of our cases, consistent with surgeon preference reported by Chapman et al., who noted ease of insertion and stable construct formation with antegrade entry [8]. The union outcomes in the current series demonstrate that 76.6% of fractures achieved normal union within 16 weeks, which is in close agreement with the union rates reported by McCormack et al., who observed early union in 74% of patients treated with intramedullary nails [6]. The delayed union (14.9%) and non-union (8.5%) rates in the present study are also comparable to results reported by Bahrs et al., who documented delayed union in 16% and non-union in 9% of patients undergoing humeral nailing [9]. The significant association between fracture complexity and poorer union outcomes in our study is consistent with observations by Denard et al., who found that comminuted and segmental patterns predispose to delayed healing [10]. Functional outcomes in our study were favourable, with 85.1% achieving good to excellent results, which corresponds closely with the findings of Brinker and O’Connor, who documented satisfactory shoulder and elbow function in 80% of their cohort [5]. The subgroup of patients with fair or poor outcomes displayed strong correlation with non-union and non-compliance with rehabilitation, similar to the pattern described by Ramo et al. [11]. Regarding complications, the shoulder impingement rate (12.8%) in our series is consistent with impingement rates between 10–18% observed by Flinkkilä et al. following antegrade nailing [12]. The radial nerve palsy rate (6.4%), with full spontaneous recovery, also aligns with the recovery patterns described by Shao et al., who reported high rates of neuropraxic recovery in humeral shaft injuries [3]. The superficial infection rate of 8.5% in this study is slightly higher than the 4–6% reported by McKee et al., which may reflect variations in follow-up compliance in government hospital environments [13]. A notable finding was the 6% loss to follow-up, which is expected in retrospective public-sector studies. Similar trends were described by Kulkarni et al., who attributed early dropout to socioeconomic factors and limited access to continued rehabilitation [14]. Overall, comparison with established literature demonstrates that intramedullary interlocking nailing offers predictable healing, acceptable complication rates, and satisfactory functional results. The procedure remains a valuable fixation option for humeral shaft fractures, particularly in trauma-heavy government hospital settings where early mobilization and reduced soft-tissue handling are clinical priorities.

This retrospective study demonstrates that intramedullary interlocking nailing is an effective and dependable modality for the management of diaphyseal fractures of the humerus, providing high union rates, satisfactory functional outcomes, and an acceptable complication profile in a government hospital setting. Most fractures achieved union within the expected timeframe, with better results observed in simple (AO 12-A) fracture patterns. Functional recovery was favourable in the majority of patients, and complications such as shoulder impingement, radial nerve palsy, and superficial infection were manageable and within reported global ranges. Although a small proportion of patients were lost to follow-up, the overall outcomes reaffirm that intramedullary nailing remains a reliable option for stable fixation, early mobilization, and predictable healing in humeral shaft fractures, especially in high-volume trauma centres serving diverse populations. LIMITATIONS The present study was retrospective in nature and relied entirely on available hospital records, which may have introduced documentation bias and limited the completeness of clinical and functional data. The study was conducted at a single government medical college with a relatively small sample size of 50 cases, which may restrict the generalizability of the findings to broader populations. Follow-up duration varied among patients, and long-term functional outcomes or late complications such as persistent shoulder impingement could not be fully assessed. Additionally, the absence of a comparison group—such as plate osteosynthesis—prevented direct comparative evaluation of surgical techniques. ACKNOWLEDGEMENT I express my sincere gratitude to Dr. Sanjeev Bhandari, Ex-Associate Professor, GMC Solapur, for his valuable guidance, constant support, and insightful suggestions throughout the preparation of this orthopaedic article. His expertise and encouragement were instrumental in shaping the scientific content and refining the overall quality of this work. I am equally thankful to Dr. Shashikant Ganjale, Ex-Associate Professor, GMC Solapur, for his continuous motivation, constructive feedback, and dedicated help at every stage of writing. His clinical experience and academic perspective greatly enriched the article. Their combined mentorship, timely inputs, and unwavering support have been truly invaluable in completing this work successfully. RECOMMENDATIONS Future studies should include larger multicentric cohorts with standardized follow-up protocols to provide stronger evidence regarding the long-term effectiveness of humerus interlocking nailing. Comparative trials between nailing and plating would help clarify indications and outcome differences between techniques. Incorporating objective functional scoring systems and radiological assessments at regular intervals would improve assessment accuracy. Training programs emphasizing proper entry point selection and nail insertion technique may help reduce complications such as shoulder impingement and radial nerve palsy. Strengthening record-keeping and postoperative rehabilitation protocols in government hospitals will further enhance patient outcomes.

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