Evaluation of Incidence of Tibial Mal Rotation after Closed Tibial Intra-Medullary Nailing and its Effects on Clinical Outcomes of the Patients: A Prospective Study

Abstract

Background:

Incidence of tibial malrotation (more than 10° of tibial rotation in comparison with contralateral tibia) following intramedullary fixation originally ranged from 0% to 6% and different complications were reported including: Cosmetic appearance concerns, impaired gait specially crouch gait when more than 30° of malrotation happens, foot adopting a pes planus position.

Materials and Methods:

This prospective study was performed from January 2022 to June 2024. A total of 245 patients with tibial mid-diaphyseal fractures underwent closed intra medullary nailing and basic data including age of the patients, their genders, BMI and surgery durations and post-operative outcome variables including lower extremity functional scale (LEFS), six minute walk test (6 MWT) and SF 36 questionnaire were collected.

Results:

From 245 of the patients 237 of them were included in the study and basic data including age of the patients, their genders, BMI and surgery durations were not significantly different between two groups (P value > 0.05). Post-operative outcome variables including LEFS, 6 MWT and SF 36 questionnaire was measured and no significant difference between two groups is reported (P value > 0.05).

Conclusion:

Age, gender, BMI, and surgical time had no meaningful relationship with incidence of tibial malrotation after closed tibial intra medullary nailing. Clinical outcomes are not significantly different between two groups, which it means that tibial torsion will not affect clinical outcomes of the patients.

INTRODUCTION

The Incidence of tibial malrotation following intramedullary fixation originally ranged from 0% to 6% and is defined as more than 10° of tibial rotation in comparison with contralateral tibial alignment.[1,2] However, in previous studies some degrees of tibial malrotation were reported asymptomatic.[3,4] Different complications were reported including cosmetic appearance concerns,[5] impaired gait specially crouch gait when more than 30° of malrotation happens,[6,7] foot adopting a pes planus position[8] and different compensatory mechanisms in isolated tibial torsion (i.e. pelvic rotation, hip abduction, and adduction, contralateral limb compensation) that all of these happens due to impaired force distribution after tibial torsion.[9]

Despite different studies investigating tibial malrotation after intra-medullary nailing of the tibia, only limited studies evaluated the functional outcome of tibial torsion.[10,11] The LEFS is one of the most commonly used methods in evaluating patients with tibial torsion because it is comprehensive and systematic.[12] Tibial mal rotation over 10° does not affect the functional outcome of flower extremities according to Theriault’s findings.[10] Theriault et al.[10] also measured 6 MWT for evaluation of the clinical outcomes of the patients both of these measurements are included in our study.

As tibial diaphyseal fractures are the most common long bone fractures[13] and tibial nailing is associated with superior outcomes and less complications, investigating one of the most complications of this procedure is of particular importance. In the presented study mal rotation following reamed intramedullary nailing of closed tibial fractures is investigated from clinical point of view and the association of its incidence with different demographic data is reported. Our aim of the study is to detect the incidence of tibial malrotation and investigating clinical outcomes of this phenomenon on the patients.

MATERIALS AND METHODS

This prospective study was performed from January 2022 to June 2024. A total of 245 patients with tibial mid-diaphyseal fractures, who were admitted and underwent closed intra-medullary nailing, were enrolled in this study consecutively. Exclusion criteria were previous ipsilateral tibial fracture, fresh or old contralateral tibial fracture, pregnancy, fractures extending to knee or ankle joints, and multiple traumas. They study was approved by the ethical committee and a written consent form was signed by all patients.

Under spinal or general anesthesia in a supine position, all of the fractures were manually reduced and operated within 3 days. A parapatellar approach was used and the fractures were stabilized with two interlocking screws on each side of the fracture. After checking the alignment of the limb and comparing it with the other side the proximal and distal screws were inserted. The tibial tuberosity is in line with the 2^nd metatarsal bone in a majority of patients. All of the tibial fractures based on AO classification were 42-A1-3 fractures in that fibula is fractured too but in none of the patient’s fibula was fixed. All of the patients included in this study were classified as ASA grade 1 by anesthesiologists.

Rotation of the tibia was assessed by using clinical examination and comparison of both legs in the patients in that more than 10° of internal or external rotations were described as tibial malrotation. The clinical examination consists of thigh foot angle (TFA) in that the patient is in the prone position and the knee flexed to 90° where the angle between the axis of the thigh and foot can then be measured. For confirmation of the patients with tibial torsion a limited bilateral CT scan imaging was performed in the supine position in that both legs were gently strapped together and computed tomography (CT) images were prepared from 3 to 4 axial cuts in the proximal (2–3 mm above the proximal tibiofibular joint) and 3–4 axial cuts in the distal part of tibia (just proximal to the tibial tallar articulation). The proximal reference line is a line drawn as a tangent to the posterior tibial cortex and the distal reference line is a line that connects the tibial and fibular centers in the cut just proximal to the tibial plafond. The torsion angle is the angle between perpendicular lines to two reference lines. The unaffected side was used as the control.

Basic data including the age of the patients, their genders, BMI, and surgery durations were collected and summarized in Table 1. Post-operative outcome variables including LEFS, 6 MWT, and SF 36 questionnaire were collected 9 months after surgery except LEFS that was assisted 3 months after surgery in addition to 9 months.

Table 1.

Basic variables (±SD)

P	Group Variable	Tibial torsion (36 patients)	Normal torsion (201 patients)	P
Gender	Male (number)	21 (8.8%)	122 (51.4%)	0.34
	Female (number)	15 (6.3%)	79 (39.3%)
Age (yeas)		34.5 (±5.4)	35.1 (±5.5)	0.45
BMI (kg/m2)		27.3 (±6.8)	27.5 (±7.1)	0.64
Surgical Time (minutes)		63.2 (±10.3)	62.1 (±9.8)	0.52

The LEFS is a questionnaire containing 20 questions about a person’s ability to perform everyday tasks. The LEFS can be used by clinicians as a measure of patients’ initial function, ongoing progress, and outcome, as well as to set functional goals. The LEFS can be used to evaluate the functional impairment of a patient with a disorder of one or both lower extremities. It can be used to monitor the patient over time and to evaluate the effectiveness of an intervention.

The 6 MWT was developed by the American Thoracic Society and it was officially introduced in 2002, coming along with a comprehensive guideline[14] and is a sub-maximal exercise test used to assess aerobic capacity and endurance. The distance covered over a time of 6 minutes is used as the outcome by that to compare changes in performance capacity.

The quality of life of patients in our study was evaluated by using the 36-item SF-36 questionnaire. The SF-36 questionnaire assesses the quality of life across two main dimensions including physical health and mental health. Each domain in the SF-36 is scored based on a 0–100 scale and higher scores indicate better health conditions. The validity and reliability of this questionnaire have been evaluated and confirmed in previous studies.[15]

Our main outcome variable in this study was LEFS that is a numeric variable and the expected difference between the two groups and standard deviation were 1.7 and 4.7 based on previous research. With α = 5% and 1-β = 80% that are frequently used in clinical research, the study population was calculated. Two-tailed test (the proportion of the two groups is different p(A) ≠ p(B)) and 3% of the loss to follow-up the final study population was calculated as 248 patients.

Statistical analysis

The collected data were entered into the statistical analyses that were carried out using SPSS vs. 24 (IBM Corp., Armonk, USA). Data were presented as means ± standard deviation or frequency (percentage) for the continuous and categorical variables, respectively. A significance level of less than 0.05 was considered statistically significant in all analyses.

RESULTS

From 245 of the patients participated in the study four of them were excluded because of insufficient documentation and refusal of participation in clinical examinations and four of the patients needed early surgical intervention due to early post-operative infection [Figure 1]. From 36 of the patients (15.1%) had more than 10° of internal or external rotation (5 and 31 patients, respectively) in comparison with the other healthy side and mal rotation after clinical examinations was acknowledged by CT scan imaging and is labeled as torsion group in our study, 201 patients had normal tibial rotation that is labeled as non-torsion group. No meaningful relationship was detected between gender and prevalence of tibial mal rotation (P value > 0.05). Average age of the patients was 34.5 ± 5.4 years old in torsion group and 35.1 ± 5.5 years old in non-torsion group that no significant difference was detected between age and occurance of tibial mal rotation (P value > 0.05). Body mass index (BMI) in torsion group had a mean of 27.3 ± 6.8 vs. 27.5 ± 7.1 in non-torsion group that was not significantly different between two groups (P value > 0.05). Surgical time was 63.2 ± 10.3 min for torsion group and 62.1 ± 9.8 in non-torsion group that were not statistically significantly different between two groups (P value > 0.05). Basic demographic data and their associated values is summarized in Table 1.

Figure 1.

Study flowchart

Outcome variables including LEFS is measured 3 and 9 months after surgery and no significant difference was detected between two groups 3 months after surgery in that LEFS mean scores were 61.2 ± 4.5 and 62.1 ± 4.8 in torsion and non-torsion group, respectively (P value > 0.05). Also, mean of the LEFS scores 9 months after surgery were 71.3 ± 4.2 and 72.2 ± 4.4 in torsion and non-torsion groups, respectively and no statistically significant difference was detected between the two groups (P value > 0.05). 6 MWT that is measured 9 months after surgery based on the standard protocol had a mean of 573.2 ± 20.3 meters in torsion group and 574.1 ± 22.1 in non-torsion group that is not statistically significant (P value > 0.05). Quality of life that is measured by SF-36 questionnaire had no significant difference between the two groups with the mean value of 88.2 ± 9.1 in torsion group and 87.9 ± 8.7 in non-torsion group (P value > 0.05). All of the outcome variables are summarized in Table 2.

Table 2.

Outcome variables and comparison between two groups (±SD)

Groups Variables	Tibial torsion (36 patients)	Normal torsion (201 patients)	P
LEFS 3 months	61.2 (±4.5)	62.1 (±4.8)	0.65
LEFS 9 months	71.3 (±3.2)	72.2 (±4.4)	0.51
6 MWT 9 months	573.2 (±20.3) Meter	574.1 (±22.1) Meter	0.71
SF 36 9 months	88.2% (±9.1)	87.9% (±8.7)	0.23

DISCUSSION

In our study incidence of tibial malrotation was 15.1% and compatible with other studies[16] and no relationship was detected between demographic data and the incidence of tibial malrotation. Though there is no clear definition of tibial torsion in the literature[17] more than 10° of tibial torsion in comparison with the uninjured side of the patient is defined as mal rotation and in our study was assessed by clinical examination and CT scan imaging. In different studies, it is assumed that rotational mal alignment greater than 10° of the lower extremity can affect knee and ankle joint biomechanics[18] but in our study, no significant difference in outcome variables was reported between the two groups and the quality of life is comparable between two groups.

Theriault et al.[10] conducted a study in that tibial torsion more than 15° was described as mal rotation and outcome variables consisting of LEFS and Olerud-Molander (points) and 6 MWT were assessed and no meaningful difference was reported between two groups. The authors come to this conclusion that tibial mal rotation will not affect clinical outcomes and this result is compatible with ours but we defined 10° of difference between two lower extremities as the threshold for tibial torsion and we did not use Olerud-Molander (points) in our study.

In another study that was conducted by Claes et al. another scale for clinical assessment in the patients was used that was Tegner Lysholm Knee Scoring Scale and consists of eight items including limp, pain, locking, stair climbing, support, and stability, swelling, and squatting. This scale was used for the patients with anterior cruciate ligament and meniscal injuries first but in the Özbek study it was used for the patients with tibial mal rotation and no significant difference in patients with tibia mal rotation or without it, was reported from a clinical standpoint.[11] Their results were compatible with ours but the main differences between this study and ours are the clinical variables that are assessed in the study and the study population that our population was larger than theirs and we assessed more clinical variables.

A cadaveric study, which was performed by Yazdi et al.,[19] they demonstrated that tibial torsion, affects knee contact pressures in that internal rotation and external rotation increase medial compartment and lateral compartment contact pressure and consequentive risk of osteoarthritis. Yagi et al.[20] reported a correlation between tibial malrotation and severity of osteoarthritis but osteoarthritis was not included in our outcome variables and their results cannot be proved or denied by our study because of the limited follow-up period but we noticed that clinical outcomes are not significantly different between patients with tibial torsion or without it in the mid-term follow-up period.

The main powers of our study are the sample size and type of the outcome variables measured in comparison with other similar studies in which a lesser group of patients with a more restricted number of outcome variables are studied but the main limitation of the presented study is a number of measured basic and maybe confounding variables (i.e. number of surgeons, different comorbidities, type of trauma, and etc.) that may affect the incidence of tibial mal rotation. We suggest larger studies including more basic variables affecting tibial mal rotation and we advise measurement of more post-operative clinical variables during follow-up period. Another study with long-term follow-up will be extremely helpful at investigating of tibial torsion and its consequences on patient’s clinical outcomes.

CONCLUSION

Our study demonstrated that age, gender, BMI, and surgical time had no meaningful relationship with the incidence of tibial malrotation after closed tibial intra medullary nailing. From a clinical standpoint presented study also demonstrated no difference between the two groups. Clinical outcomes that were measured in our study including LEFS, 6 MWT, and SF 36 questionary were comparable between the two groups. Our study comes to the conclusion that tibial torsion greater than 10° in comparison with tibial torsion lesser than 10°, will not affect patient’s clinics and clinical outcome variables but larger studies with detailed clinical variables and long-term follow-up must be done to acknowledge our results.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.