Clinical outcomes of the intramedullary humerus nailing system in the treatment of humerus fractures

INTRODUCTION

Humerus fractures occurrence accounts for 7-8% of all fractures.¹ Although fractures of humerus at different locations has different incidence. Proximal humerus fractures has the most occurrence which account for 5-6% of all fractures observed in accident and emergency departments and are more prevalent in the elderly particularly in the women.^1-3 The humerus fracture has >10% occurrence among children. The majority of humerus fractures among paediatric population, about 70% are distal humerus fracture (supracondylar fractures) while proximal humerus fractures accounts for 24% followed by diaphysis fracture of about 4%.⁵ Humerus shaft fractures has relatively low occurrence of 1.2% and shows bimodal distribution for men and women which means occurrence of such fractures are more frequent among young and old age population.^1,6,7 On the other hand, the distal humerus fractures has very low incidences of 0.5% with prevalence of 5.8-8.3 cases/10⁵ of population.^1,8 Moreover the incidences of humerus fractures also depends on the geographic location and demographics of that region.^2,7 In all of the studies associated with the epidemiology of humerus fracture, it is found that the female population has higher occurrence of such fractures and shows bimodal distribution for all fractures in humerus bone.

The main reason for the humerus fractures in younger population is the result of high energy trauma, while in elderly it is low energy trauma. The latter is the result of osteoporosis in the elderly population.⁹ The proximal and distal humerus fractures are predominantly found in the elderly population because of low energy trauma which are managed using operative or non-operative techniques whereas humerus shaft fractures are usually the result of high energy trauma.¹

The treatment of the humerus fractures depends on the patient's associated injury. The treatment includes conservative treatments, internal fixation through plate and IMN (Intramedullary nail) fixation and external fixator. The choice of the treatment associated with patient's injury. Majority of humerus fractures are treated non-operatively and usually recommended for stable, minimally displaced fractures or fractures with minimal articular surface involvement. Although, the treatment of proximal humerus fracture is debatable due to differences in the management of different types of fractures.^10-14 The non-operative treatment complications includes osteonecrosis, nonunion, malunion, stiffness and rotator cuff dysfunction.¹² Due to the high occurrence of proximal humerus fractures in older patients with osteoporotic bone which prevent stable internal fixation, usually non operative treatment is preferred with some exceptions.^15,16 The operative fixation of proximal humerus fractures is indicated for the complex fractures because of, high energy trauma in adults which includes fixation techniques from Nail, plate or arthroplasty.^2,17 A study conducted by Xiaoqing et al shows that IMN nail for humerus shows better result as compare to plate fixation for the treatment of proximal humerus fractures, although plate fixation offer treatment of different type of fracture which lacks in the treatment from IMN.²¹ The operative treatment for humerus shaft fractures shows better functional results compared to non-operative treatment.¹⁸ As compared to the plate fixation in the humerus shaft fractures, use of IMN shows lower risk of infection, secondary radial nerve palsy and shorter operation duration.^2,19 The distal humerus fracture are managed non-operatively or operatively using plate fixation.²⁰

In the case of operative treatment for humerus fractures there are wide variety of implants are available but to date there is no consensus method of reduction and fixation. Intramedullary nailing system was introduced to reproduce the success seen with the IMN technique in the lower extremities. The expected advantages of IM nails for humerus includes less soft tissue mutilation, closed reduction and periosteum-sparing stabilization in complex fractures. However, several complications were reported which gets reduced due to advancement in design and technology which have led to better results.²²

The primary objective of this study to evaluate the performance of intramedullary humerus nailing system by assessing the functional and clinical assessment of patient who were treated using the intramedullary humerus nailing system manufactured by Kaulmed Pvt. Ltd., India. The system includes KN-5F Intramedullary cannulated humerus Nail, KN-5G reconstruction Nail, cannulated and KN-5H reconstruction cannulated intramedullary humerus nail along with other fixation screws and end caps as shown in Figure 1.

METHODS

A retrospective study of 26 patients with humerus fracture was carried out at Mesoamerican university, Quetzaltenango, Guatemala. Data was gathered from the patients treated with the KN-5H humerus nailing system during October 2021 to September 2022. Total 40 patient were screened who have humerus fracture and eligible for operative treatment. Out of which 26 patients are selected in a row who met the inclusion criteria. The data collected from the hospital includes age, gender, fracture type, Aetiology of injuries and post-operative visits assessment.

The study is approved by the institutional ethics committee.

Inclusion criteria

Male or female participants who were at least 18 years old and had recently suffered a proximal humerus and humerus shaft fractures due to an injury between 12 to 72 hours before pre-operative investigation were included in the research. The patients included in the study have suffered from the fractures that are amendable from the humerus nailing system. The patients with minimum follow-up period of twelve months are included in the study.

Exclusion criteria

Patient age greater than 80 years; compounded fracture; Proximal humerus and shaft fractures along with fracture in other limbs, pathological fracture; Subjects who had problems with alcohol abuse, those who were detained or were in the process of being detained, those who had an infection at the site of the operation, patients who had any active local infections, those who had an allergy to the metal, ASA grade greater then II, open fractures (Gustilo-Anderson IIIa and IIIb) and patients who had problems with neuromuscular diseases were also excluded from this study.

Treatment

The patients with traumatic cases of proximal humerus and humerus shaft fracture were assessed whether operative management is required or not. The assessment was based on the radiograph taken during emergency treatment. The patients who required open reduction and fixation with intramedullary nail were then admitted and planned for surgery.

The surgery was performed based on the AO principles of fracture management that includes Anatomic reduction followed by stable fixation, early, active mobilization and preservation of blood supply. The surgery was carried out using a tibia plate made of titanium alloy (Ti-6Al-4V) or stainless steel (316LRM) manufactured by Kaulmed private limited in Sonipat, Haryana, India. The surgical approach followed for intramedullary humerus nailing fixation is based on the technique provided by Kaulmed Pvt. Ltd. The method of approach can be referenced from review article by Balker et al.² Post-operative immobilization period is for 6-7 weeks in an abduction pillow sling, though immediate wrist, hand, elbow and passive shoulder ROM is permitted. Physiotherapy exercise includes pendulum exercise which can be done after surgery while actively-assisted and full ROM exercise begins after 4-8 week depending on fracture healing. Sutures are typically removed after 4-6 weeks. The full weight bearing can be done after the twelve weeks.

Statistical analysis

All statistical analyses performed using Minitab. Results are reported as means ± SD for continuous variables and number (%) for nominal variables. Endpoints summarized using descriptive statistics (Mean, median SD, minimum, maximum). For normal distribution, parametric tests will be applied; otherwise, equivalent non-parametric tests will be applied for analysis. For normally distributed data, intra group at various follow-up using paired t test using statistical software. P≤0.05 to be considered as statistically significant.

RESULTS

From 26 patients who were selected as part of the retrospective clinical study to evaluate the performance of Intramedullary humerus nail, 11 were men and 15 were female (Table 1). The Female patients were more vulnerable in the study. The youngest patient in our series was 20 years and the oldest 69 years. The patient's average age was 43.8 years, as indicated in (Table 1). In adults the primary cause of proximal tibia accidents includes vehicle accidents, fall from heigh and sport injury whereas in elderly (age>65) the primary cause includes low energy trauma that includes fall different activities (Table 2). According to the AO/OTA classification and Neer classification, fractures in the humerus bone were classified in this study into the following categories: 11A2-A3 (2-part fracture), 11B1 (3-part fracture), 11C1-C3 (4-part fracture), 12 A/B/C (shaft fractures); 5 patients had 11A type fractures, 4 patients had 11C type fracture, 2 patients had 11C type fracture and rest 15 patients has diaphysis or shaft fracture (Table 3). Patient with soft tissue injury also given in the Table 3. The mean follows up period was 15 months (Range 13-24 months).

Out of 26 patients, 19 were classified as ASA I (a normal healthy patient) and 7 as ASA II (a patient with a mild systemic disease). At each follow up, radiological evaluation was performed to assess bone union progress. Meantime taken for full bone union was 14 weeks with a range of 10-18 weeks. No patient had delayed union and non-union. At each follow up, functional assessment was performed using ROM of shoulder and elbow and clinical assessment was performed from pain evaluation using VAS scale and measuring complication rate.

Functional assessment

The overall functional assessment was excellent in 92.3% patients, moderate in 5.75% patient and poor result in 1.95% patients (Table 5).

Clinical assessment

Pain was recorded for each patient at their respective visits through VAS score (Figure 2), the average pain scale at 3 week was 5.4, 3.4 in 16-week and 1.2 in 24 weeks. The pain due to implant impingement was 1.2 after 12 months.

Complications

There were no pre- or intra-operative complication noted. The post-operative complication includes superficial infection in 1 patient, 3 patients had nail impingement, 1 patient had shoulder stiffness and had pain in adduction. No non-union and mal-union was observed in the patient assessment. No Implant related complication was reported.

DISCUSSION

The non-operative approach or conservative management is the preferable treatment method in simple fracture but takes longer duration to heal and return of patient to daily activities. Moreover, the conservative approach does not produce effective result in case of complex fracture of proximal humerus and shaft. Due to this, operative stabilization is preferred by both the patients and surgeon. The operative approach provides patient with rapid relief of symptoms and restoration of Joints.

For the operative approach, intramedullary nail and locking plate fixation have been the main choice of internal fixation in the case of proximal humerus fracture and humeral shaft fracture. The decision for the use of which internal fixation device is a debatable issue. The bio-mechanical comparative study by Edward et al shows locking plates has advantage over IM nails in bending and torsional resistance while similar study by Kitson shows nail is superior to plate in terms of axial, torsional and bending load.^23,24 Plate osteosynthesis has yielded high success rate but requires extensive dissection with the risk of radial nerve damage and refracture after implant removal. Advantages of intramedullary nailing have made it the choice of surgical treatment, but the use of unlocked flexible nails has been complicated by poor rotational stability and slipping of the nails causing joint irritation.²⁵ Locked nailing overcomes these deficiencies, and results in satisfactory therapeutic outcome. It has been considered the treatment of choice in humeral shaft fractures in the recent past.²⁶

In this study, we have evaluated post-operative results of the intramedullary humerus nail used the patient with proximal humerus fracture and humeral shaft fracture. Out of 26 patients selected in the study, 11 were men and 15 were women and mean age is 43.8 years, which confirms the epidemiology data as shown in study by Charles et al.¹ The aetiology data suggests that a younger population is more prone to having humerus fractures due to driving two-wheelers and indulgence in more physical activities like sports, while older population is likely to have such injuries primarily due to fall. The data correlates with epidemiology study by Tytherleigh et al.⁶ The majority of patients that are selected for the study are adults and suffered humerus fracture hue to high energy trauma while some elderly patients included had humerus fracture injuries due to low energy trauma. The majority of humerus fractures are shaft fractures followed by proximal humerus fractures while distal humerus fractures injuries are not the part of the study. This data does not correlate with the results shown in the study by Charles et al, this is due to fact this study is for intramedullary humerus nail which is primarily recommended for the shaft fractures.¹

The post-operatively results show no major complication which require re-intervention or re-surgery. There was no delayed union and non-union. The results in this study aligns with the results from the meta-analysis by Xiaoquig et al.²¹ The benefits of using IM nail is proximal and shaft fractures of humerus are less intra-operative blood loss, operation duration, fracture healing time, post-operative complication and post-operative complication which show significant results as compare to locking plate osteosynthesis.²⁷ The IM Nails also show better function and clinical results in terms of radiographic evaluation, ROM, VAS and complication rates in this study. Potential deleterious effects of antegrade humeral nailing on shoulder function have been debated the most. This can be due to impingement of proximal nail tip or proximal locking screw due to adhesive capsulitis or due to rotator cuff tears. In most of the studies with antegrade nailing, 80-95% of patients regained their normal shoulder function.²² In the study by Ozturkmen et al excellent therapeutic outcome was reported in 80% patient while it was moderate in 13%, and poor in 8% patients.²⁸ In our study, 92.3%patients had excellent shoulder function with near normal range of motion of shoulder while 5.75% had moderately good shoulder function. These patients had impingement of the proximal end of the nail. One patient had severe shoulder stiffness with significant restriction of shoulder motion.

Early mobilization of elbow and shoulder is critical in attaining full ROM post-operatively in patient having humerus fracture. The movements and the functional ability of the shoulder depend on the patient’s adherence to rehabilitation program and early intensive physiotherapy hastened the recovery of shoulder function.

Closed intramedullary nailing with an interlocking nail is a safe and reliable method of treating humeral shaft fractures. Among available surgical modalities, closed nailing is the least invasive surgical technique and has the least chance of post-operative infection. It reduces the duration of the hospital stay. Complications like non-union can be avoided by intraoperative compression and avoiding distraction at fracture site. Certain technical aspects like burying the proximal nail end at the entry portal are essential in avoiding impingement and to gain better shoulder function.

In the current study, a humerus fracture is treated with an intramedullary nailing device created and produced by Kaulmed private limited, India. Our study's limited sample size and retrospective methodology were its main drawbacks. Despite these limitations, the results were in line with what we had anticipated before the clinical trial ever started. Although the primary clinical outcome in the current trial was pain, the data indicate that pain can be reduced with good results in a shorter amount of time. No significant complications such as mal-unions, non-union, or deep infection was found.

CONCLUSION

Closed intramedullary nailing is an excellent, least invasive surgical option available to manage humeral shaft fractures with early fracture consolidation and better union rates. It decreases the hospital stay, provides early rehabilitation and reduces morbidity. It is ideal in patients with poly-trauma and osteoporosis. Early intensive physiotherapy hastens the recovery of shoulder function.

The current retrospective case series, demonstrates the effectiveness of KN-5H humerus nailing system as treatment with a high percentage of union without any clinical, functional and bio-mechanical complications.

ACKNOWLEDGEMENTS

The author(s) acknowledge the clinicians, doctors and hospital staff for supporting and allowing us to conduct the study. The author(s) also thankful to Kaulmed private limited for providing the opportunity to participate in the study.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: The study was approved by the institutional ethics committee

REFERENCES

1. 1. Court-Brown CM, Caesar B. Epidemiology of adult fractures: A review. Injury. 2006;37(8):691-7.
2. 2. Baker HP, Gutbrod J, Strelzow JA, Maassen NH, Shi L. Management of Proximal Humerus Fractures in Adults-A Scoping Review. J Clin Med. 2022;11(20):6140.
3. 3. Roux A, Decroocq L, El Batti S, Bonnevialle N, Moineau G, Trojani C et al. Epidemiology of proximal humerus fractures managed in a trauma center. Orthop Traumatol Surg Res. 2012;98(6):715-9.
4. 4. Wang MQ, Youssef T, Smerdely P. Incidence and outcomes of humeral fractures in the older person. Osteoporos Int. 2018;29(7):1601-8.
5. 5. Daag Jacobsen S, Marsell R, Wolf O, Hailer YD. Epidemiology of proximal and diaphyseal humeral fractures in children: an observational study from the Swedish Fracture Register. BMC Musculoskelet Disord. 2022;23(1):96.
6. 6. Tytherleigh-Strong G, Walls N, McQueen MM. The epidemiology of humeral shaft fractures. J Bone Joint Surg Br. 1998 Mar;80(2):249-53.
7. 7. Tsai CH, Fong YC, Chen YH, Hsu CJ, Chang CH, Hsu HC. The epidemiology of traumatic humeral shaft fractures in Taiwan. Int Orthop. 2009;33(2):463-7.
8. 8. Yetter TR, Weatherby PJ, Somerson JS. Complications of articular distal humeral fracture fixation: a systematic review and meta-analysis. J Shoulder Elbow Surg. 2021;30(8):1957-1967.
9. 9. Kanis JA, Oden A, Johnell O, Jonsson B, de Laet C, Dawson A. The burden of osteoporotic fractures: a method for setting intervention thresholds. Osteoporos Int. 2001;12(5):417-27.
10. 10. Sarmiento A, Kinman PB, Galvin EG, Schmitt RH, Phillips JG. Functional bracing of fractures of the shaft of the humerus. J Bone Joint Surg Am. 1977;59(5):596-601.
11. 11. Hanson B, Neidenbach P, de Boer P, Stengel D. Functional outcomes after nonoperative management of fractures of the proximal humerus. J Shoulder Elbow Surg. 2009;18(4):612-21.
12. 12. Misra, A.; Kapur, R.; Maffulli, N. Complex Proximal Humeral Fractures in Adults-A systematic Review of Management. Injury. 2001;32:363-72.
13. 13. Olerud P, Ahrengart L, Ponzer S, Saving J, Tidermark J. Internal Fixation versus Nonoperative Treatment of Displaced 3-Part Proximal Humeral Fractures in Elderly Patients: A Randomized Controlled Trial. J Shoulder Elb Surg. 2011;20:747-55.
14. 14. Goudie EB, MacDonald DJ, Robinson CM. Functional Outcome After Nonoperative Treatment of a Proximal Humeral Fracture in Adults. J Bone Joint Surg Am. 2022;104(2):123-38.
15. 15. Patel AH, Wilder JH, Ofa SA, Lee OC, Savoie FH 3^rd, O'Brien MJ et al. Trending a decade of proximal humerus fracture management in older adults. JSES Int. 2021;6(1):137-43.
16. 16. Schumaier A, Grawe B. Proximal Humerus Fractures: Evaluation and Management in the Elderly Patient. Geriatr Orthop Surg Rehabil. 2018;9:2151458517750516.
17. 17. Misra A, Kapur R, Maffulli N. Complex proximal humeral fractures in adults--a systematic review of management. Injury. 2001;32(5):363-72.
18. 18. Van de Wall BJM, Ochen Y, Beeres FJP, Babst R, Link BC, Heng M, van der Velde D, Knobe M, Groenwold RHH, Houwert MR. Conservative vs. operative treatment for humeral shaft fractures: a meta-analysis and systematic review of randomized clinical trials and observational studies. J Shoulder Elbow Surg. 2020;29(7):1493-504.
19. 19. Beeres FJP, Van Veelen N, Houwert RM, Link BC, Heng M, Knobe M et al. Open plate fixation versus nailing for humeral shaft fractures: a meta-analysis and systematic review of randomised clinical trials and observational studies. Eur J Trauma Emerg Surg. 2022;48(4):2667-82.
20. 20. Yetter TR, Weatherby PJ, Somerson JS. Complications of articular distal humeral fracture fixation: a systematic review and meta-analysis. J Shoulder Elbow Surg. 2021;30(8):1957-67.
21. 21. Shi X, Liu H, Xing R, Mei W, Zhang L, Ding L, Huang Z, Wang P. Effect of intramedullary nail and locking plate in the treatment of proximal humerus fracture: an update systematic review and meta-analysis. J Orthop Surg Res. 2019;14(1):285.
22. 22. Sheriff F. The outcome of interlocking nailing of humeral shaft fracture, a one-year hospital-based study. IJOS. 2018;4(2):95-9.
23. 23. Edwards SL, Wilson NA, Zhang LQ, Flores S, Merk BR. Two-part surgical neck fractures of the proximal part of the humerus. A biomechanical evaluation of two fixation techniques. J Bone Joint Surg Am. 2006;88(10):2258-64.
24. 24. Kitson J, Booth G, Day R. A biomechanical comparison of locking plate and locking nail implants used for fractures of the proximal humerus. J Shoulder Elbow Surg. 2007;16(3):362-6.
25. 25. Lin J, Shen PW, Hou SM. Complications of locked nailing in humeral shaft fractures. J Trauma. 2003;54:943-9.
26. 26. Marchetti PG, Vicenzi G, Impallomeni C, Landi S, Surdo V. The use of elastic nails for intramedullary fixation of humeral fractures and non-unions. Orthopedics. 2000;23:343-7.
27. 27. Chapman JR, Henley MB, Agel J, Benca PJ. Randomized prospective study of humeral shaft fracture fixation: intramedullary nails versus plates. J Orthop Trauma. 2000;14(3):162-6.
28. 28. Ozturkmen Y, Dogrul C, Dogan A, Karli M. Locked intramedullary nalllng of humeral shaft fractures. Ulus Travma Derg. 2002;8(3):164-9.