Prospective study on functional outcome of distal femur fracture treated by open reduction and internal fixation using distal femur locking plate in Tibebe Ghion Specialized Hospital, Bahirdar, North West Ethiopia

Abstract

Background

Distal femur fractures account for 6% of femur fractures. The treatment of distal femur fractures is challenging. Historically, nonoperative management has been the mainstay of management, which has evolved to operative management. There is no single implant used for all types of distal femur fractures. The implant evolves with time. The introduction of a distal femur locking plate (DF LCP) has had a great impact on the treatment. In developing countries like Ethiopia, there is scarcity of studies on functional outcome of operative treatment. So, this study aimed to assess the functional outcome of distal femur fractures treatment using distal femur locking plate.

Methods

This prospective cohort study was carried out among adult patients with distal femur fractures treated using distal femur locking plate at Tibebe Ghion Specialized Hospital from august 2022 to July 2023. A total of 60 patients with AO Type A and Type C fracture were included. All patients were followed for 6 months. Functional outcomes were assessed using Neer’s scoring system. Data was entered and analyzed using SPSS 27. Frequency, mean and cross tabulation were used to summarize descriptive statistics. Multinomial logistic regression was used to test the associations.

Results

In our study out of 60 patients ,48.3% (29) had excellent functional outcomes, 30% (18) had good functional outcomes, 10% (6) had fair functional outcomes and 11.7% (7) had unsatisfactory functional outcomes according to Neer’s scoring system. Patients with closed distal femur fractures had 5 times higher probability of excellent functional outcome than those patients with open distal femur fractures (AOR (2.49(5.8 ,1.07)). Patients who had regular follow up had 7 times higher probability of excellent functional outcome than those who had no regular follow up (AOR 7.16(1.11,46.22)). The average union period was 4.63 months, with only 2 patients experiencing delayed union.

Conclusion

Closed fracture and regular follow up were determining factors for better functional outcomes. Closed fractures preserve the biological environment, which facilitates early fracture healing. The regular follow up helped patients to assess their rehabilitation status and pick any complication early.

Introduction

The femur is the longest, strongest and heaviest tubular bone in the human body and one of the principal load bearing bones in the lower extremity [1]. Distal femur includes from metaphyseal-diaphyseal junction distally extending to intraarticular surface. The most common mechanism of injury is road traffic accident. The mechanism of injury depends on age of the patients. In young patient, high energy injury are the most common causes like road traffic accident and in old patients its usually caused by low energy mechanism like fall from standing height. Distal femur fracture also occurs in periprostatic area in those patients who had knee total arthroplasty. Distal femur fractures cause significant morbidity with different debilitating complication if it’s not managed appropriately [2].

Fractures of the distal femur have an estimated incidence of ten per 100 000 and account for 6% of all femoral fractures [3]. These injuries have a bimodal distribution with the first peak being observed in young people resulting from high-energy trauma and the second peak being observed in the elderly osteoporotic population [1, 4, 5]. It causes considerable morbidity and mortality, especially in elderly individuals [6]. Many treatments have been used in the management of these injuries. Historically, people were treated in bed with skeletal traction. More recently, surgical fixation of distal femur fracture has become mainstay of treatment. Implant used for surgical fixation include 95-degree angle blade plate (ABP), dynamic condylar screw (DCS), distal femur locking plate, intramedullary nail (IM Nail), External fixator (EX -Fix), arthroplasty and distal femur replacement. With advancement of technology, distal femur plates has been improved by incorporating hybrid screw hole for locking and non-locking compression screw and it also provide multi-plane screw trajectory to hold many small fragment and coronal fractures components [2, 7, 8]. Despite these advances, Controversy still exists regarding the surgical treatment method of distal femoral fractures. The type of internal fixation procedures is dependent on fracture type, patient status and the surgeon’s preference. While intramedullary nails have comparable advantages as locking plates such as percutaneous placement, indirect fracture reduction, soft tissue protection, success in osteoporotic bone, and high healing rates, locking plates have become the most commonly used method to treat distal femur fracture [7, 9]. There is currently no consensus about the best way to treat these fractures [10].

In our hospital, we use DF LCP for the treatment of adult patients with distal femur fractures. However, in developing countries, there is a scarcity of evidence on the management of distal femoral fractures and the functional outcomes of distal femur fractures fixed with a Distal Femur Locking Plate. Therefore, this study aimed to fill this gap by providing evidence on the functional outcome of distal femur fracture treatment using DF LCP for better practice.

Methods

This study was conducted in northwest part of Ethiopia where most of the people are farmer who feed most of the remaining Ethiopians by their agricultural product. People in this region are mostly armed because of their heroic historical background rooted from era of kings when most leaders were from this part of Ethiopia. They have a culture of shooting gun in different public gathering including weeding, mourning, religious and national holydays. There are many unintentional shootings in their villages like when kids manipulates and when they try to clean their gun without knowing that it is loaded with bullet. More ever, during this study period, there was active war between armed force and federal government which was started since the current governing party took the power.

This was a prospective study of 60 patients with distal femur fracture treated by open reduction and internal fixation using distal femur locking compression pate (DF LCP), who were admitted to the Department of Orthopedics of Tibebe Ghion Comprehensive Referral Hospital from August, 2022 to July, 2023, with a minimum of 6 months of follow-up.

Permission was granted from the ethical committee of our hospital with protocol number of 618/2022 before we started the study. After preoperative counselling about the treatment, surgery and whole process of the study, written consent was obtained.

In this study patients older than 18 years with distal femur fractures of AO/OTA type 33 A (A1, A2, A3) and type 33 C (C1, C2, C3) were included. Patients with AO type 33B distal femur fractures, pathological fractures, associated injuries and periprosthetic fractures were excluded from this study. Most of our patients had either type 33 A or type 33 C and we used distal femur locking plate for fixation. However, we had few patients with type 3B fractures and we used screw only for fixation. Since this study aimed to study functional outcome of distal femur fracture treatment using distal femur locking plate only, we excluded patients with AO/OTA type 33B distal femur fractures. We excluded all other associated fractures and knee joint ligament injuries other than isolated one side distal femur fracture considering their confounding effect on outcome of our patients.

At time of presentation in our hospital, all patients were approached according to the ATLS principle. We resuscitated patients with hemodynamic instability and we gave antibiotics and tetanus prophylaxis for those patients with open fracture. Then, all patients were splinted, and standard X-rays and CT- scan were obtained. After imaging, all fractures were classified by the AO/OTA classification system. For patients with open fractures, debridement was performed. Knee spanning Ex fix was applied for those with open fractures and high energy closed fracture sparing zones for definitive surgery. For the remaining fractures, we applied distal tibia skeletal traction with a bump under the distal part of the thigh. For those open fractures with unclean wound debridement was repeated until the wound became ready. Fifty-seven patients were admitted to the ward for elective surgery but for 3 patients definitive fixation using distal femur locking plate was performed on the day of their presentation to our hospital. According to our hospital protocol, patients with complex intra-articular fracture are operated for definitive fixation (ORIF) on elective basis in working day.

All the definitive surgeries were performed under spinal anesthesia after preanaesthesia team evaluated them. All materials needed for surgery were prepared one day before surgery. Patients were positioned supine on a radiolucent table even though we did not use the C- arm for most fixations. The knee was flexed 30° by putting the bolster below the knee and sometimes by flexing the distal end of the bed to relax the gastrocnemius and facilitate exposure as well as reduction. A small bump was placed under the ipsilateral buttock to avoid external rotation of the lower limb.

Lateral parapatellar and swashbuckler approaches were used for almost all patients. Both approaches were selected based on fracture pattern, and they allowed good exposure. Anatomic reduction of the intra-articular fragment was performed first and the fragment was held by provisional K-wire. For fractures AO type 33 C1 and C2 lagging out of the plate was performed on intercondylar split then reduction with a shaft was performed. The next step was applying anatomic DF LCP and held with bone clamp with the shaft proximally and with patellar clamp distally then a 6.5 mm locking screws were inserted distally, and 4.9 mm locking screws were applied proximally to the shaft. For some patients we used one or two 4.5 non locking screw to compress the pate on shaft proximally. We added medial plate for 3 patients with AO type C2 and C3 who had instability with lateral column fixation only. There was no bone gap which needed bone graft. The wounds were washed thoroughly with bleach and normal saline, sometimes with H2O2, and then were closed by layer. We applied drainage for 7 patients with soft tissue loss and had dead space. (Fig. 1)

Fig. 1

Distal femur fixation technique using DF LCP via the swashbuckler approach for 32-year-old pregnant patient after she sustained RTA of 5 h. duration

On the immediate post operative day, control knee X-ray, post operative CBC and initiation of knee ROM were performed. Patients were advised to perform quadriceps strengthening and hamstring stretching exercises and weight bearing was avoided until 6 weeks after surgery. After 6 weeks, the patient was advised to start partial weight bearing using a bilateral crutch. Full weight bearing was allowed when radiological evidence of healing appeared.

The follow-up were 2 wks., 6wks, 3 months and 6 months after definitive surgery. At the 2nd week, the stitches were removed, the knee ROM was assessed, and the patients were referred to the physiotherapy clinic. On the 6th week, 12th week and 6-month follow-up days, AP and latera knee X-rays were obtained (Fig. 2), fracture healing was checked clinically and radiographically, range of motion of the knee was evaluated, weight bearing status was checked, and any complications were assessed. On the 6th month follow-up day, the functional outcomes of all the patients were analyzed using Neer’s scoring system. (Table 1)

Fig. 2

Follow-up X-ray of a 30-year-old patient with distal femur fractures treated with ORIF by DF LCP, on 1st, 12 weeks and 6 months post operative day

Table 1 Functional outcome Assessment tool based on Neer’s scoring system

Data was entered to SPSS 27. Frequency and cross tabulation were used to summarize descriptive statistics. Model fitness was checked by comparing the full model (containing all predictor variables) against null model and our data had a good fit for model. Using multinomial logistic regression independent variables including; alcohol and smoking history, medical illness, mechanism of injury, time of arrival after trauma, AO type, time of first antibiotics, open or closed fracture, time of definitive fixation after trauma and regularity of follow up were checked for the presence of associations where P-value < 0.05 was considered as statistically significant.

Results

Sociodemographic characteristics of the study participants

A total of 60 adult patients with distal femur fractures were treated by ORIF using DF LCP. There were more males than females with a ratio of 14:1. The mean age was 27.5 years old. The youngest patient was 18 years old, and the oldest patient was 66 years old. Most patients were younger than 40 years of age (88.2%). (Table 2).

Table 2 Sociodemographic characteristics of adult patients with distal femur fractures treated with open reduction and internal fixation who were followed at TGSH, Bahir Dar, Ethiopia, 2023

Mechanism of injury, fracture pattern and treatment approach

In this study, the most common mechanism of injury was bullet injury, which accounted for 65% (39) of injuries, followed by RTA, which accounted for 21.7% [11], and fall injury, which accounted for 13.3% [8]. No other mechanism of injury was observed in this study. The left side was more commonly affected, 77% patients than the right side, 23% of patients.

In this study, 48 patients (80%) had open fractures, whereas 12 patients [12] had closed fractures. The most common fracture pattern was intra-articular (AO type C1, C2, C3) fracture in 32 (53.4%) patients, and 28 (46.6%) patients had extra articular fractures (AO type A1, A2, A3) (Table 3). In this study, only 29 (48.3%) patients arrived at our hospital within 24 h. However, more patients did not arrive at golden hour (72 h after trauma). Twenty-one patients (35%) arrived with in the first week, and 10 (16.7%) patients arrived between the 1st and 2nd weeks after trauma.

Table 3 AO classification pattern of distal femur fracture treated by ORIF using DF LCP among adult patients who were followed at TGSH, Bahir Dar, Ethiopia, 2023

For five patients with open fractures, debridement was performed two times, whereas for the remaining 43 patients with open fractures, single debridement was performed before definitive fixation. Only five (10.8%) patients took antibiotics before three hours after trauma (Fig. 3). For 38 patients, the knee spanning external fixation was performed, and for 10 patients, distal tibia skeletal traction was applied after irrigation and debridement. For the remaining 12 patients, a posterior gutter was applied. Fifty-seven patients were admitted to the ward for elective surgery. For three patients, definitive fixation was performed emergently. For 52 patients, a knee CT scan was performed to study the fracture pattern and for preoperative planning. All admitted patients were prepared according to the protocol for elective surgery.

Fig. 3

Time of antibiotic initiation for open distal femur fracture after trauma

Definitive surgical treatment

In the first week after admission, 70% (42) of patients underwent surgery for definitive fixation via elective surgery. Seventeen (28%) patients underwent surgery between the 1st and 2nd weeks after admission because of their wound status and patient burden during the war. Only one patient underwent surgery after two weeks of admission due to a contaminated wound, which required two rounds of debridement. Approximately 95% (57) of patients had lateral column fixation only, and three (5%) patients had both-column fixation. The most commonly used surgical approach was the lateral parapatellar approach in 34 (56%) patients. The Swashbuckler approach was used in 23 (38.33%) patients, and the combined approach was used in three (5%) of patients.

Follow-up

In this study, only 41 (68.3%) of the patients had regular follow-up according to the schedule, whereas 19 (31.7%) patients missed one schedule, they had 2-to-4-week delay from the regular schedule. All were linked to physiotherapy at 2nd week of their follow up. However most patient only do home physiotherapy and visited physiotherapy clinic after 6 week of their surgery (Table 4).

Table 4 Time of initial physiotherapy clinic visit for adult patients with distal femur fractures treated with ORIF and followed at TGSH, Bahir Dar, Ethiopia, 2023

Using our follow-up, X-ray union was assessed based on our operational definition of union (defined as complete formation of at least 3 cortices and patient can weight bear without pain) [13] (Fig. 4). Of the 60 patients, 51 (85%) patients achieved bony union between 4 and 5 months, five (8.3%) patients achieved bony union at 6 months and four (6.7%) patient achieved bony union at more than 6 months (Table 5).

Table 5 Fracture union time of distal femur fractures treated by ORIF using DF LCP and followed at TGSH, Bahir Dar, Ethiopia, 2023

On the last follow-up day, functional outcome assessment was performed using Neer’s functional outcome score. Among the 60 patients, 48.3% (29) of patients had excellent, 30% [14] of patients had good, 10% [6] of patients had fair and 11.7% [7] of patients had poor functional outcomes. In this study, all patients with AO type A1 distal femur fractures (36.7%) had excellent functional outcomes. Poor outcomes were observed among patients with AO type C2 and C3 (Table 6).

Table 6 Cross tabulation of AO type with functional outcome of distal femur fracture treated by ORIF using DF LCP and follow-up in TGSH, Bahirdar, Ethiopia, 2023

Regarding the range of motion, the mean range of motion was 88 degrees of flexion, with a minimum of 20 degrees and maximum flexion of 135 degrees. Six patients (10%) achieved 130-degree knee flexion, 30 (50%) of patients achieved 100 degrees flexion, and 10 (16.7%) patients achieved 80–90 degrees flexion at the 6-month follow-up. In addition, 14 patients (23.3%) patients achieved 60 degrees or less.

Complications

Only 4 patients experienced immediate postoperative complications before discharge. Two of them had wound dehiscence, whereas two patients developed deep infection, for which one debridement and culture specific antibiotic was given. All of the patients were discharged improved.

At the 6 months follow-up, approximately 23.6% [15] of the patients had stiffness, 10 patients (16.7%) had pain, and 5 patients had infection. Two patients had superficial infections and responded to oral antibiotics and wound care. Three patients had deep infections, for which the implant was removed in 2 patients, and incision and drainage was performed in 1 patient. Culture-specific antibiotics were started for all patients with deep infections, and they responded well. (Fig. 4)

Fig. 4

A 32 years old male patient with distal femur fracture with a DF LCP that was infected at 6 months follow-up day

Associated factors

Compared to patients with open fractures, patients with closed distal femur fractures were 2.5 times more likely to have excellent functional outcomes with AOR [2.49, (5.8, 1.07)]. Patients who had regular follow-up had a 7-fold greater probability of having excellent functional outcomes with AOR [7.16, (1.11, 46.22)] (Table 7).

Table 7 Multinomial regression of factors associated with functional outcomes in adults with distal femur fractures treated with ORIF via DF LCP who were followed at the TGSH, in Bahir Dar, Ethiopia, from 2022 to 2023

Discussion

The mean age in this study was 27.5 years, and 88.2% of our patients were younger than 40 years of age. In contrast, in other studies, the mean age was more than 40 years [16]. The mechanism of injury in this study was not related to osteoporosis. In this study, 57 male patients, with only three female patients, were included. A similar pattern was also reported in other studies that included 28 male patients and two female patients [15]. In this study, the most common mechanism was bullet injury (65%), followed by RTA (21.7%) and fall injury (13.3%). This is because, in this study area, male civilians are armed, and they shoot in different public gatherings, including weeding, mourning, and religious holidays. There was also war in the last 3 years, particularly in the northern part of Ethiopia. However, in other studies RTAs were the most common mechanism (74.6%), followed by falls (23.6%), with no bullet injuries [17]. Based on the AO classification of fracture, this study revealed that 32 (53.4%) patients had AO type C and 28 (46.6%) patients had AO type A, which was similar to the findings of other studies in which 65% of patients had AO type C, 20% had AO type B and 15% of patients had AO type A [18].

Infection was found in 5 (8.3%) patients in this study. A similar rate of infection was reported in 1 study, with an 8% [11] incidence, however, our study finding was slightly greater than other reports, which reported a rate less than 8%[22, 26].

This study revealed that the knee range of motion ranged from 20 to 135 degrees. Overall, 76.66% of patients had a range of motion of 90 degrees or more and 23.4% of patients had a ROM of 60 degrees or less. Earlier studies support this finding; Saini et al. [13] reported a knee ROM of 0 to 110 degrees, and Neetin et al. reported a ROM of up to 130 degrees [18]. Patients with 60 degrees or less ROM complained of stiffness at the 6th month of follow-up.

Distal femur fracture union was defined as the complete formation of at least 3 cortices, and the patient could bear weight without pain. In this study, the union rate was 85% at 4.63 months and 15% of delayed union. We did the union assessment based on radiological finding and clinical evaluation of their pain-free weight bearing ability which includes the time before and after their specified follow up day. Similar results were reported in the study by Amin et al. [11], with a mean union time of 4.86 months.

Functional outcome was assessed at the 6 months follow-up using Neer’s score. Among the 60 patients 48.3% (29) had excellent functional outcomes (≥ 85), 30% [14] had good functional outcomes (70–85), 10% [6] had fair functional outcomes (55–70), and 11.7% [7] had unsatisfactory functional outcomes (< 55). Overall, 78.3% of patients had good to excellent outcomes and a total of 21.7% of patients had fair to unsatisfactory outcomes. In contrast, in a study of 30 patients, Neetin et al. reported that 33% had excellent, 52% had good, 11% had fair and 4% had unsatisfactory functional outcome [18]. In another study, Saini et al. reported, among 34 patients 62% excellent, 32% good and 6% fair with no unsatisfactory outcomes [17].

This study showed that closed fractures were significantly associated with excellent functional outcomes. Soft tissue is the most important biological environment for fracture union. When an individual is injured, the blood supply of the fracture will be disturbed, which will increase the risk of infection and decrease the chance of healing. In closed fractures, soft tissue is more likely to be preserved, which will improve fracture union and decrease the chance of infection with better functional outcomes [14]. Similar result was reported in study performed in India in 2021 in which the average duration of union for closed fractures was 4.25 months (16–18 weeks) and for open fractures, the average duration of union increased to 5.86 months (22–23 weeks) [11].

In this study, regular follow-up had a significant impact on functional outcomes. Previous studies have shown similar findings [12]. During regular follow-up, patient condition and fracture status are assessed to identify and treat any complications early before they worsen. The level of adherence to the rehabilitation protocol is also checked, and rearrangement can be performed. If patients miss the regular follow-up, it will be difficult to assess their progress, and the chance of having complications will increase [19]. In this study, we found that those who underwent regular follow-up had excellent outcomes.

Strengths and limitations

Strength

• This was a prospective cohort study with continuous follow-up and detailed clinical, radiological and laboratory evaluations of all patients.

• This is the first such study in Ethiopia.

• There were more patients included in this study than in other studies reviewed.

Limitations

• Its single center, noncomparative and nonrandomized study design.

• The follow-up duration was short.

• Even though we included more patient than other studies we reviewed, a sample size of 60 is still not enough for conclusion on efficacy of DF LCP.

Conclusion

This study revealed excellent to good functional outcomes in most patients with both AO type A and AO type C distal femur fractures treated with DF LCP with some preventable complications. Closed fracture and regular follow-up were determining factors for better functional outcomes. Closed fractures preserve the biological environment, which facilitates early fracture healing and allows the patient to return to routine activity. Regular follow-up allows physicians to evaluate the clinical and radiological status of the fracture fixation, which helps clinicians pick and treat complications early. Patients who did not undergo regular follow-up had poor functional outcomes because of missed complications and failure to receive proper rehabilitation. This study concluded that DF LCP is a reliable option for the treatment of AO type A and AO type C distal femur fractures.