Management and outcome of patients with femoral head fractures: The mid-term follow-up with injuries and associated prognostic factors

Treatment and Management

The treatment approach and timing for recovery for each patient were dependent based on the fracture pattern and associated injuries. The need for operative intervention was determined based on the general guidelines: hip instability, large intraarticular fragments greater than 2mm, and bone, or cartilaginous fragments in the joint space[17, 22]. In cases of open reduction and internal fixation, the anterior Smith-Peterson (S-P) approach and posterior Kocher-Langenbeck (K-L) approach were used depending on the type and location of the fractured fragments. The choice of fixator was made based on the size and location of the fracture, and the surgeon’s preferences. We used reconstruction plates and interfragmentary Herbert screws to obtain stable anatomical fixation in the acetabulum and femoral head respectively. For patients undergoing operative intervention, operation time, intraoperative blood loss, surgical approach, and type of fixation were all recorded. In our study, the reduction was performed within six hours of fracture-dislocation. If the patients underwent non-operative management, skeletal traction was continued for at least 6 weeks and was deemed to have stable fracture patterns. Postoperatively, patients were encouraged to perform an isometric exercise for the quadriceps and lower limb muscles. Simultaneously, the patients with THR were asked for early mobilization postoperatively.

Evaluation of Clinical Outcome

Patients' outcomes and complications were determined based on a review of the clinical and radiographic results from their most recent follow-up. The median follow-up period was 36 months (range of 24–84 months). The Brooker classification was used to evaluate HO formation. Patients with HO did not receive any prophylactic radiation or NSAIDs other than analgesic medication for acute pain management. The presence of post-traumatic osteoarthritis, osteonecrosis of the head, and heterotopic ossification changes was assessed with functional score and radiological changes by experienced orthopedic surgeons during each follow-up visit. Other complications such as post-operative infection, deep venous thrombosis (DVT), and sciatic nerve injury were also documented. Sciatic nerve injury and its peroneal division were diagnosed during a physical examination. Functional recovery was evaluated according to the MHHS’s criteria at the latest clinical follow-up.

Modified Harris Hip Score (MHHS)

MHHS is a patient-based questionnaire which is a relatively simpler process to assess the pain, functional status, and functional activities of the hip. It is a tool to calculate the score of the functional outcome based on the physical examination components by saving the time and energy of the clinical practitioner. In the absence of a patient, the questionnaires can be completed over the phone or through correspondence. The threshold for classification of outcome using the MHHS was as follows: <70 (poor result), 70–79 (fair result), 80–89 (good result), and > 90 (excellent result). The MHHS is a surgeon-derived outcome measure that contains eight items representing the main aspects of pain and function gait, and functional activities [23–25].

Statistical Analysis

Statistical analysis was performed with GraphPad Prism 8.0 software (GraphPad Software, Inc., CA, USA). For quantitative variables, the data were expressed as mean ± standard deviation (SD). The sample size for each variable is included in the figure legends. P-values were calculated using one-way ANOVA P-value of < 0.05 was considered to be significant.

Patients and Injury Characteristics (Demographics)

Sixty-one patients were assessed for eligibility in this study as shown in the Flow diagram (Fig. 1). In total, 50 patients with femoral head fractures met the eligibility criteria and were included in this study. There were 37 men and 13 women with a median age at the time of injury of 40 years (range 16–65). Thirty-one patients sustained their fractures from a motor vehicle accident, fourteen from a fall, two from sports, two from a bike, and one from a workplace-related accident. There were eighteen Pipkin I fracture, ten Pipkin II, eight Pipkin IIII, and fourteen Pipkin IV fracture according to Pipkin classification. The car accident was the most common injury mechanism (31/50), followed by fall injury (14/50). Patients were stratified by ISS ranking into four groups (a) mild (ISS, 9), (b) mild-to-moderate (ISS, 10–15), (c) moderate-to-severe (ISS, 16–25), and (d) severe (ISS > 26). There were 20 mild, 11 mild-to-moderate, 17 moderate-to-severe, and 2 severe ISS patients. There were 20 patients with the orthopedic case of femoral head fracture and 30 patients with orthopedic cases associated with polytrauma. Patient demographics, classification, and associated injuries are listed in Table 1. 

Management

Out of 50 patients, thirty-seven (74%) patients were managed with ORIF for the femoral head and acetabulum, five (10%) patients underwent immediate THR, and eight (16%) patients were treated non-operatively. The overall treatment in relation to Pipkin classification is given in Table 2. The non-operative intervention was mainly rendered to patients with Pipkin Type I (28%) fractures, while ORIF was performed mostly for Pipkin type II (80%) and type IV (79%) fractures. Of note, the majority (60%) of patients who had immediate THR were within the Pipkin type III subgroup. Two patients with Pipkin III fracture and one patient with Pipkin IV fracture, who were treated operatively using ORIF, required an eventful conversion to secondary THR. In addition, one patient with pipkin II fractures who were treated non-operatively required secondary conversion to THR. We next examined different treatment variables, such as non-operative, ORIF, immediate THR, and combined ORIF/THR, concerning each Pipkin subtype (Fig. 2).

Table 2. Table showing treatments, complications and outcomes of femoral head injury.

Note: ORIF= open reduction and internal fixation, AVN=avascular necrosis, PTA= post traumatic arthritis, HO=Heterotopic ossification, THR= Total Hip Replacement

Regarding the surgical approaches, the anterior (Smith - Peterson) approach was used in 18 patients while the posterior (Kocher-Langenbeck) approach was used in 19 patients. The posterior K-L approach was used for immediate or secondary THR. Three patients were treated with a lateral stab approach. Two patients were treated using combined anterior and lateral approaches. Cannulated screws were used in the lateral approach that is percutaneously inserted into the femoral neck by a stab incision. Three patients who underwent ORIF using a lateral approach and two patients who underwent ORIF using the posterior approach developed AVN accompanied by posttraumatic arthritis and required eventful conversion to a secondary THR. Patients treated nonoperatively were believed to be too fragile for surgery due to the severity of their associated injury and medical comorbidities or were deemed to have stable fracture patterns, and therefore treated with traction.

The association between operative approaches with Pipkin subtypes was also examined. An anterior approach was mainly used for patients with Pipkin I and Pipkin II fracture (Fig. 3 and Fig. 4), while the majority of patients with Pipkin III and IV fractures were treated using the posterior approach. Combined anterior and lateral stab approaches were used in the Pipkin III fracture (Fig. 5). The lateral stab approach was rendered in three patients with Pipkin III fractures.

Complications

The overall incidence of mid-term complications (median follow-up 36 months) was evaluated. Six patients developed AVN for an overall incidence of 12%. Four (8%) of these patients required eventful conversion to a secondary THR. Sixteen patients (32%) had radiographic criteria of PTOA at their latest clinical follow-up. Two patients (4%) had iatrogenic sciatic nerve injuries. There was one patient who was diagnosed with post-operative superficial infection and one with DVT in the lower limb. Both of these patients were improved by receiving medication and without surgical management. Eight patients (16%) developed HO. This was graded as Brooker I in all eight patients. None of these patients required operative intervention.

We next examined the relationship between preferred surgical approaches and complications encountered, mainly AVN, PTA, sciatic nerve palsy, and HO (Table 3). Odds ratio analysis revealed that the incidence of HO (all Brooker I) was 1.7 times higher after the posterior approach compared to the anterior surgical approach. However, this difference was not statistically significant. There was no incidence of HO when a lateral approach was used. Similarly, post-traumatic arthritis incidence was estimated confirmed when a lateral approach was used than a posterior or an anterior approach, while 1.6 times higher after a posterior approach in comparison to the anterior. Although, this difference did not reach statistical significance. Out of 19 patients, two patients who were treated using the posterior approach developed AVN. Interestingly, all the patients who underwent the lateral approach developed AVN, while there was no incidence of AVN when an anterior approach was used. Similarly, none of the patients treated with the combined surgical approach suffered major late complications.

Table 3. Table showing treatments, complications and outcome of femoral head injury according on pipkin classification.

Functional outcome

Clinical and radiographic data were reviewed for all patients at their latest clinical follow-up and were grated according to MHHS. The overall clinical results, according to the MHHS criteria were excellent in 2 (4%) patients, good in 16 (32%), fair in 22 (44%), and poor in 10 (20%) patients. Four patients with poor outcomes developed AVN and PTA and underwent eventful conversion to secondary THR.

We next investigated the relationship between the results of MHHS and Pipkin Classification (Table 4). Based on the Pipkin classification, the overall outcome interpretation was further subdivided. Majority of the patient with Pipkin I fracture showed excellent functional outcomes, while the outcome of patients with Pipkin III and Pipkin IV fractures was relatively poor compared to Pipkin I and Pipkin II. Statistical analysis revealed a significant (p = 0.0024) difference in outcome among pipkin subtypes, indicating a variance of functional outcome value according to Pipkin classification in femoral head fracture (Fig. 6a). However, this might also be due to the potential confounding effect of different treatment strategies. We further examined the relationship between outcome, according to the Harris Hip score, and each treatment variable (non-operative, ORIF, Immediate THR) in Table 5. For the non-operative group, the results were good in 5(62.5%), fair in 2(25%), and poor in 1(12.5% patients). Among the surgically treated patients, the outcomes were excellent in 2(4.7%), good in 11(26.1%), fair in 20 (35.7%), and poor in 10(21.4%) of patients. The outcome of 5 (100%) patients who underwent primary intention THR was fair. Because of the small number of patients in our cohort, we were unable to examine the influence of the confounding effect of treatment strategy on functional outcomes. Furthermore, the relationship between functional outcomes and the operative approaches was also examined. The outcome of patients treated using the anterior approach was excellent in 11%, good in 39%, fair in 44%, and poor in 6% of patients. While the outcome was mostly fair in 9 patients (47%), 4(21%) were good and 6(32%) poor using the posterior approach. The relationship between functional outcome and the surgical approaches used was also examined (Table 6). While there was no difference in outcome between the anterior and posterior approach, a majority (79%) of patients treated using the posterior approach had a poor or fair outcome. None of the patients treated using the lateral approach showed better (excelled or good) outcomes (Fig. 6b).

The particularity of Femoral Head fractures and Prognostic Factors

The femoral head fracture with hip dislocation is a true emergency in orthopedic trauma. Long-term fracture and dislocation of the femoral head will damage the blood supply of the femoral head, leading to subsequent avascular necrosis of the femoral head [18]. In addition, a complication such as traumatic arthritis may develop due to poor reduction of fracture in the weight-bearing area of the articular surface [30]. Therefore, timely diagnosis and prompt reduction of the associated hip dislocation should be performed to prevent further damage to peripheral vessels and improve outcomes. Treatment measures were either operative or non-operative. The treatment approach and timing for recovery for each patient were dependent based on the fracture pattern and associated injuries. Using skeletal traction [9, 31–33], which is frequently used as an initial management of femoral head fracture, 16% of cases in our study were managed non-operatively to decrease the risk of chondrolysis. The criteria for non-operative intervention were determined based on anatomic reduction of hip dislocation and femoral head fracture, intraarticular fragment displacement of less than 1 cm, absence of bone or cartilaginous fragment in the joint space, and hip stability. Those fractures that did not meet such criteria were treated operatively [8, 16]. The operative measure included fracture fixation using ORIF or THR. Operative management is generally preferred when the fracture is severe and extends superior to the fovea. In our study, ORIF was mainly rendered to Pipkin II (80%) and Pipkin IV (79%) fracture, while THR was performed mostly within Pipkin III fracture (37.5%).

The long-term follow-up analysis after operative (ORIF) or non-operative treatment regimens on Pipkin I injuries demonstrated that the best results (80% excellent or good) were accomplished. Although a statistical difference was not found (P = 0.59), the non-operative intervention seems to result in a better outcome than an operative intervention. Several studies support this non-operative management of Pipkin I fracture and controversies remain regarding the surgical management of these fractures [34–37]. The fact that only 4 cases were managed non-operative. Thus, we do not make an absolute recommendation in favor of non-operative when dealing with Pipkin 1. However, when the head fractures are less than 1 mm, absence of loose bodies in the joint space, stable hip joint with good relation of the head with the glenoid[38], non-operative intervention may be an adequate intervention. Pipkin II fracture involves a larger portion of the weight-bearing femoral head surface and is a more challenging injury [34]. The majority (80%) of these fractures were operated with internal fixation of the fragment. This is in line with current principles of managing Pipkin II fractures with anatomical reduction and surgical fixation [11, 18, 34].

Pipkin Type III fracture is the least frequent type that involves dual insult to the femoral head and neck. All eight of our Pipkin III injuries underwent operative intervention, using ORIF and/or THR, while none of the patients demonstrated the best results (excellent or good). Although treatment options for Pipkin III fracture range from open reduction and rigid fixation to arthroplasty, the outcome is highly dependent on age, delay in surgery, and degree of comminution. Generally, young patients with Pipkin III fractures should be aimed at preserving the joints, while THR may be a reasonable option for the elderly[6, 39]. In our study, two (out of five) patients with Pipkin III fracture who were operated on with fixation of fragment required conversion to secondary THR. This trend supports the opinion of published literature that postulates Pipkin III fracture as a predictive of secondary THR in femoral head fracture [7, 40].

Pipkin IV injuries lead to the worst outcome as they involve both the femoral head and the acetabulum. A majority of our patients with Pipkin IV injuries were treated with ORIF, however, there was no significant improvement in outcome among different treatment methods. One of the particular characteristics of this injury group is that, despite the type of intervention used, it is often challenging to address whether the approach should be directed to the acetabulum, femoral head, or both. These fractures require anatomical reduction and internal fixation of the femoral head and acetabulum lesions with attention toward restorations of hip congruency and hip stability.

Femoral Head Fracture and Significance of Surgical Approach

Despite advances in several surgical approaches for femoral head fracture management, controversy exists concerning the choice of optimal surgical treatment. The anterior S-P approach offers good exposure and easier access to the fractured head; thus, it is more suitable for the treatment of Pipkin I and II femoral head fractures [41]. Such an anterior approach can significantly reduce blood loss and operation time, and therefore reduce the incidence of avascular necrosis of the femoral head, compared to the posterior K-L approach. However, the often-quoted disadvantage of the anterior-based approaches has been the association with increased heterotopic ossification[4, 13, 17, 42]. Similarly, this approach has also been linked to further damage to any residual anterior blood supply to the femoral head although, the anatomical studies do not support this theory [43, 44]. The posterior-based approach can provide direct visualization of the acetabular fracture and an opportunity for simultaneous repair of the femoral head and acetabular fracture as seen in Pipkin type IV injuries. In this study, the majority of patients with Pipkin I and II were treated using the anterior approach while the posterior was mainly used in Pipkin III and Pipkin IV fractures. Correlation analysis showed no statistical difference (p > 0.05) in outcome between the anterior and posterior approaches. Although it should be noted that irrespective of our findings, the choice of surgical approach and outcome is frequently determined by the fracture pattern and the overall injury severity characteristics.

Factors Regarding Complications and Outcomes

Regarding major complications, our findings suggest that the likelihood of AVN is higher when a lateral approach is used. This could be due to the severity of Pipkin III injuries and the confounding factors such as displaced femoral neck fracture, damage to vascular structures, and inadequate reduction that mostly leads to subsequent AVN despite surgical approaches. The AVN is one of the main long-term complications secondary to iatrogenic insult or due to damage during the initial injury[22]. Clinical symptoms of AVN may present early (from 6 weeks) or late (several years following injury) with the collapse of the femoral head accompanied by PTA[45]. In our study, all patients who developed AVN showed poor functional outcomes. While two patients who underwent a posterior approach for ORIF developed AVN. It is important to note that our mean follow-up time may be too short to capture all patients who develop clinical symptoms of AVN and thus longer follow-up times are required for detailed analysis of the incidence of AVN. Similarly, HO is one of the most common complications after operative fixation, with an incident associated with the anterior surgical approach [13, 18, 26]. In our study, odds ratio analysis demonstrated a trend to a higher incidence of HO (all Brooker stages) after the posterior approach relative to the anterior one, which was statistically not significant. Although it is unclear, this result could be implicated due to extensive surgical dissection of gluteal muscles during fixation[46]. However, only eight (16%) of our patients who developed HO, all with a Brooker grade I, had no impact on the final functional outcome. Post-traumatic osteoarthritis is another common complication of femoral head fracture management and its incidence is directly related to the severity of the initial injury[28]. A higher incidence of PTA was found in the case of a posterior or lateral approach respectively versus an anterior approach. This finding, however, could be attributed to the fact that majority of the patients who developed PTA had fracture that belonged to Pipkin type III (37.5%) and IV (43%) category.

Overall, our study has for the first time used a modified Harris Hip (MHHS) score for the clinical evaluation of femoral head fracture. Operative management using ORIF is carried out in the majority of cases with Pipkin I and Pipkin IV fracture. Non-operative intervention may be adequate for Pipkin I fracture and should be recommended only after acceptable evaluation of the fracture reduction, articular congruency, hip stability, and the absence of loose fragments in joint space using modern imaging techniques. The anterior surgical approach has provided promising results with a lower incidence of major complications in Pipkin I and II fracture, making it probably the best approach for operative management of Pipkin I and II fracture. The incidence of HO is also shown to be highly prevalent with the posterior K-L approach. Regardless of rigid and anatomical fixation, the degree of trauma with pipkin III or IV creates complexity in physio-anatomical healing and poor functional outcome.

This study was subject to several limitations. Firstly, this study was small in size for a single center. Secondly, the study enrolled a small number of patients treated with a different approach. Thirdly, the power of the statistics was low due to the lack of a higher number of enrolled patents, different approaches, and management. Relatively short follow-up duration was also a limitation of this study because it might be insufficient to assess post-traumatic osteoarthritis. Therefore, it is important to conduct a large prospective study using validated outcome scores, that will develop the fracture classification and operative approaches.