Knee Pain After Retrograde Intramedullary Nailing with Surgical Implant Generation Network of Femur Shaft Fractures at Public Hospitals in Bahir Dar City, Ethiopia: Analysis of 6-Months Follow-Up Results

Introduction

In low- and middle-income nations, traumatic injuries are a major cause of morbidity and mortality.¹ Femoral shaft fractures have a significant worldwide impact, with up to 2.9 million fractures occurring each year and low- and middle-income countries (LMICs) are disproportionately affected.² The average annual incidence of femoral shaft fractures inlow- and middle-income nations ranged from 15.7 to 45.5 per 100,000 persons.² For instance, in Tanzania, the annual incidence of femoral shaft fractures is as high as 18.4 per 100,00.³ Femur fractures are the most common traumatic injury encountered by orthopaedic surgeons and have a bimodal distribution, with younger people typically experiencing high-energy trauma and older people experiencing lower-energy trauma. These fractures are linked to significant mortality and morbidity and can result in severe injuries including nonunion, delayed union, and implant failure, as well as long-term, irreversible impairments.⁴ The surgical treatment option is more effective than conservative management.⁵

Since the 1970s, intramedullary nailing has been widely used to repair shaft fractures and has emerged as the gold standard.⁶ An intramedullary nail is a metal nail that is surgically inserted into the fractured long bone to straighten and hold fractures. The SIGN Nail is an intramedullary nail secured in place by interlocking screws with a 1–1/2-degree bend at the distal end and a 9-degree bend at the proximal end for simpler insertion. However, the SIGN Fin Nail does not require interlocking screws at the distal end, which makes surgery simpler and significantly faster.⁷ Early definitive therapy within 24 to 48 hours after systemically the patient is stable lowers the risk of pulmonary problems, infection rates, and death. Recently, the practice of retrograde nailing has been growing in acceptance and its main Indications for use include femur and tibia fractures (floating knee injuries), bilateral femur fractures, pregnancy, and morbidly obese individuals.⁶

Knee discomfort is the most complaint after retrograde nailing Surgical Implant Generation Network (SIGN).⁶ Even when surgery is technically successful and the union is achieved following femoral fracture, people nevertheless report impairment and discomfort in the knee. Many scholars agree that after a femoral shaft fracture, knee discomfort poses a serious functional challenge.⁸ Ricci et al reported knee discomfort in as much as 36% of the individuals with femoral shaft fractures.⁹ Various studies have reported many complications following intramedullary nailings like knee stiffness, implant failure, no-union, infection and protruding nails.¹⁰ One of the most common complications identified secondary to intramedullary nailing of the femur was chronic knee pain.^11,12 This may significantly hinder the patient’s ability to do his job and other everyday or recreational activities.¹³ Its prevalence has been observed to reach 16.1%.¹⁰ Several studies have indicated a significant occurrence of knee pain with estimates ranging from 20% to 86% and even 17% of the patients may experience moderate-to-severe pain years after surgery.^14,15 Brewster,¹⁶ in his systematic review, stressed that 40–53% of the individuals who had retrograde intramedullary nailing may experience knee discomfort.

Despite the use of the SIGN Standard Nail or Fin Nail for femur fractures being supported by growing evidence, little is known about the associated outcome. To the best of the authors’ knowledge, this is the first study to assess the clinical outcome of retrograde SIGN Standard Nail or Fin Nail femoral nails in Ethiopia. Therefore, the objective of this study was to examine knee pain and its associated factors among patients who underwent retrograde femoral nails at Tibebe Ghion Comprehensive Specialized Referral Hospitals (TGCSH) and Felege Hiwot Comprehensive Specialized Hospitals (FHCSH) over 2 years.

Materials and Methods

Study Setting

The study was carried out at TGCSH and FHCSH’s orthopaedics and trauma surgery department. TGCSH and FHCSH are found in the capital city of Amhara Regional State, Bahir Dar city. It is located 565 km from Addis Ababa to the north direction. It was established to serve 2000 people per day when it was first launched in 2011 E.C./2018 G.C. It mostly provides services at low cost or even at free cost to individuals who cannot afford care elsewhere. The hospital has more than 500 beds in all wards, including more than 67 beds in the ward of surgery with a total of 10 orthopaedic surgeons (1 of them is on fellowship) and 24 residents specializing in orthopaedic surgery.^17,18 Operations are performed every day of the week for emergency cases and 4 days a week for elective cases. The department has one large operation room with two operating tables. The hospital has a separate Surgical Implant Generation Network (SIGN) follow-up clinic which is used to offer follow-up services for SIGN patients, and report the surgeries. The study was conducted on SIGN patients in SIGN clinics by reviewing charts from the hospital record rooms and online database records from SIGN online surgical database (SOSD). The study was conducted from January 2020 to December 2022.

Study Design

A hospital-based cross-sectional study was carried out using data that had been collected from patients’ medical records, the SIGN online surgical database (SOSD), and patient interviews.

Populations and Eligibility Criteria

All patients who had been admitted to Tibebe Ghion and Felege Hiwot comprehensive specialized hospital’s Orthopedic surgery department with the diagnosis of femoral bone fractures and treated with either SIGN Standard Nail or SIGN Fin Nail using retrograde surgical approach were the source of the population whereas all patients who had operated for femur fractures with either retrograde SIGN Standard Nail or retrograde SIGN Fin Nail with healed fracture from January 1, 2020, to December 31, 2022, at TGSH and FHSH were the study population.

Inclusion and Exclusion Criteria

All patients with femur fractures who underwent either a retrograde SIGN Standard Nail or SIGN Fin Nail between January 1, 2020, to December 31, 2022, at TGSH and completed 6 months of follow-up post-operation were included and patients with incomplete SIGN database online documentation, patients with non-healed femoral fracture and did not access through phone calls were excluded from the study.

Sample Size and Sampling Technique

All patients who underwent either a retrograde SIGN Standard Nail or SIGN Fin Nail for the treatment of femur fracture from January 1, 2020, to December 31, 2022, at TGSH were included and a convenience sampling technique was used to recruit study participants.

Data Collection Tool and Procedure

Data extraction checklists were developed after reviewing relevant existing literature and prepared in English language. Data collectors have used this checklist to extract data from the patient chart, phone interview and SIGN online database. From medical records and the SIGN online database, a list of all patients who underwent surgical intervention for a femoral shaft or femur fracture at the TGRH trauma centre between January 2020 and December 2022 was generated. Thus, a total of 110 with femur fractures which met all the requirements for inclusion in the study were generated. Using the hospital’s database of patient demographic data, which included phone numbers and emergency contact information, attempts were made to call patients who had undergone either a retrograde SIGN standard nail or SIGN Fin Nail. Patients who were successfully contacted were asked to answer a phone survey on their post-operative experience, including knee pain status and 85 patients were successfully contacted. Medical records were obtained from the department of the card room, and a structured checklist was utilized to gather information on the patient’s diagnosis, types of injury, mechanism of injury, location of fracture, surgical approach, and sociodemographic factors (age, sex, and place of residence). Data were collected by three nurses with one public health professional serving as a supervisor.

Data Quality Control

Before the actual data collection, the checklist was pretested and adjusted based on the results. Data collectors received intensive training for 2 days on how to collect the data and keep to keep patients’ information confidentiality.

Outcome Variable

Knee pain: In this study, patient self-report data on knee pain were assessed during follow-up at 6 months and through a phone call if the patient did not come at 6 months of post-operation.

Data Processing and Analysis

EpiData version 3.1 was used to enter the obtained data before being exported to SPSS version 25 for analysis. Microsoft Office Excel was used to draw some figures. Descriptive statistics were used to determine the frequencies and percentages of patients’ characteristics. Tables, figures, and frequency were used to display the results. To examine the association between knee pain and its associated factors, biavirable and multivariable logistic regression analyses were performed. A P-value of 0.05 or below was deemed statistically significant.

Results

Socio-Demographic Characteristics of Study Participants

A follow-up evaluation of 110 patients and their medical records over 6 months was done, with a response rate of 95.6%. Five study participants were excluded because they were not accessed through a phone call to assess knee pain status following retrograde SIGN nail. Regarding the age of the study participants, the mean age was 31.74±13.3 SD years, with ages ranging from 17 to 75 years. The majority of study participants (64.5%) were between 15 and 30 years. In terms of sex, the majority of the cases 87 (79.1%) were male patients (Table 1).

Table 1 Socio-Demographic Characteristics of Study Participants at TGCSH and FHCSH, Bahir Dar City, Amhara Region State, Northern Ethiopia, from January 2020 to December 2022, 2022 (n=110)

Patient-Related Characteristics

A total of 110 patients with femur fractures were treated with either a SIGN Standard Nail or SIGN Fin Nail using a retrograde surgical approach during the study period. The majority of the patients who had femur shaft fractures were farmers. All fractures were reduced and reamed manually. The fractures were either in the middle third (60.9%) or lower (30.1%) of the femoral shaft. Fifty-six (50.9%) of the femur fractures treated with retrograde SIGN Nail were closed. The most common cause of femur fracture was a road traffic accident 54 (49.1%) and mainly affected the middle shaft 66 (60%) followed by distal femoral shaft fracture 44 (40%) (Table 2).

Table 2 Injury-Related Characteristics of the Study Participant at TGCSH and FHCSH, Bahir Dar City, Northern Ethiopia, from January 1, 2020, to December 31, 2022 (n=110)

Treatment-Related Characteristics

The mean interval between fracture and intramedullary nail (IMN) was 9.84±12.15 days. Concerning nail entry (51.80%) of femoral nails were inserted through the medial para patellar (16.40%) lateral para patellar and (31.80%) patellar tendon splitting (Table 3).

Table 3 Treatment-Related Characteristics of the Study Participant at TGCSH and FHCSH, Bahir Dar City, Amhara Regional State, Northern Ethiopia, from January 1, 2020, to December 31, 2022 (n=110)

Prevalence of Knee Pain

During the follow-up period, we identified 110 cases of femur fracture treated with retrograde SIGN nail from January 2020 to December 2022 and there were 40 cases of knee pain among 110 patients included in the study. This makes the prevalence of knee pain 36.4% (95% CI: 31.36–39.54) among the total patients. The majority of the patients complained of knee pain while walking up/down (34%), squatting (33%) and after long-distance walking (26.4) (Figure 1).

Figure 1 Showing different conditions in which patients noticed knee pain at TGCSH and FHCSH, Bahir Dar city, Amhara Regional state, northern Ethiopia, January 1, 2020 to December 31, 2022 (n=40).

Associated Factors of Knee Pain

In the binary logistic regression analysis, age of study participants, screw to the medial cortex, time of injury to nailing, and fracture site were associated with knee pain at p-value <0.05.

In multivariable binary logistic regression analysis, time interval from injury to SIGN nail fixation, fracture site and screw penetration to medial cortex were found to be significantly associated with the occurrence of knee pain with a p-value ˂0.05. Those patients treated with retrograde femur SIGN nail and screw penetrate medial cortex has 9 times (AOR=9.30, 95% CI: 2.90–12.74) likely to develop knee pain than the medial cortex is intact. The odds of developing knee pain in cases with fixation done between 15 and 29 days after injury were 4.2 times (AOR=4.23, 95% CI: 1.28–13.92) higher than those cases treated before 15 days. Furthermore, the odds of developing knee pain among patients with distal femur shaft fracture was 2.671 times (AOR=2.67, 95% CI: 14.01–7.03) higher than those patients with middle shaft fracture (Table 4).

Table 4 Bivariable and Multivariable Logistic Regression Analyses of Factors Associated with Knee Pain at TGCSH and FHCSH, Bahir Dar City, Amhara Regional State, Northern Ethiopia, from January 1, 2020 to December 31, 2022 (N=110)

Discussion

This is the first study conducted in Ethiopia to assess knee pain after retrograde SIGN nail is done for a patient with a femur fracture. After retrograde intramedullary nailing, knee discomfort is one of the most often reported complications. Accordingly, the frequency of knee pain secondary to retrograde SIGN nail treatment for femur fracture in this study was relatively high (36.4%), which implies knee pain remains to be a therapeutic challenge. This finding agreed with the result of the meta-analysis of postoperative complications of retrograde intramedullary nailing in distal femoral fractures,¹⁹ which reports knee pain frequently occurs following retrograde intramedullary nailing more than other alternatives. However, the current finding is lower than the reports of Acharya.²⁰ He concluded that up to 70% of the patients have knee pain after a retrograde nail. The possible reason for this discrepancy might be due to variations in the study setting, sample size, study period and socioeconomic status among the study population.

The current finding is, however, higher than what is reported in a study conducted by Shah et al,²¹ which states that 23% of the patients had complained of knee pain following retrograde SIGN nail treatment. The knee pain has reportedly been attributed to surgical technique and the placement of distal screws.²² Papadokostakis et al²³ in their systematic review described knee pain as a common complication of retrograde femoral nailing; however, they observed a statistical variation in the incidence of knee pain between femoral shaft fractures and distal femur fractures. They found that 16.5% of the patients with distal femur fractures treated with a retrograde nail have knee pain, compared to 24.5% of the patients with femoral shaft fractures. The possible reason for the higher prevalence in the present study might be due to the utilization of large sample size and a short follow-up period (6 months) to assess knee status compared to the studies conducted by Shah et al.²¹

In a study conducted in Tanzania, the most common cause of femur fracture was motor accidents, likewise in the present study the most common cause of femur fracture was a road traffic accident. The most common type of fracture seen was middle shaft fracture which was similar to the finding of Tanzanian studies.²⁴ It has been stated that there are a number of causes for the sharp increase in death rates have attributed to increase in urbanization, bad road conditions, irresponsible driving, ineffective law enforcement and regulation of road safety, and the use of alcohol and recreational drugs while driving.²⁵ For instance, a study from Tanzania concluded that the increases in death rates have been attributed to an increase in the number of motorbikes on the road, especially motorbike-taxi drivers, as well as the lack of legal driving licenses and safety equipment for these vehicles.²⁶ In this study, the mean time from injury to intervention or surgery was 9.8 days. Approximately a similar finding was reported from Uganda which states the mean time to surgery was 13.2 days.²⁷

Shah et al²¹ demonstrated that use of long screw has significantly associated with the presence of knee pain and they report that 19% of patients desired the removal of symptomatic screws after the union. Brewster, M.¹⁶ also reported in his systematic review, 37% of knee discomfort experienced after surgery was related to the use of prominent metal-work and a majority of the cases were resolved if the metal was removed. Similarly, the present study also reported that screwing to the medial cortex was significantly associated with higher odds of developing knee pain. Furthermore, our results were in line with Ostrum et al²² as they note that 21% of patients wanted the removal of e distal screws following union. So interlocking screws of the proper length should be inserted at the knee, and internal rotation oblique radiographs should be taken to confirm the screw’s length in light of the distal femur’s rhomboid shape anatomy. This will help to keep these patients from having to return to the operating room to have their hardware removed because of prominent screws.²⁸

In this study, we observed that fracture site was significantly associated with higher odds of knee pain. The patients who sustained an injury to the distal shaft were more likely to experience knee pain than one who sustained an injury to a middle shaft. In contrast Shah et al²¹ reported no association between knee pain and fracture site.

Furthermore, the current study identified that the time of injury to nailing is another factor significantly associated with knee pain. We found no study supporting these findings. However, the possible justification by the fact that some activities like running, long-distance walking, squatting, and rising from sitting before the successful union of bones may worsen knee discomfort.

Conclusions

This study concluded that although retrograde intramedullary nail fixation is an effective method for femur fracture, it frequently results in knee pain. In this study, we observed that approximately 4 of 10 patients suffered from knee pain. Time from injury to nailing, use of screw to the medial cortex and fracture site was significantly associated with knee pain. Therefore, knee pain may be prevented by applying early surgical intervention as soon as an accident occurs and avoiding the use of prominent metalwork.