Intraoperative fluoroscopic protocol to avoid rotational malalignment after nailing of tibia shaft fractures: introduction of the 'C-Arm Rotational View (CARV)'

PURPOSE

Rotational malalignment (≥ 10°) is a frequent pitfall of intramedullary-nailing of tibial shaft fractures. This study aimed to develop an intraoperative fluoroscopy protocol, coined 'C-Arm Rotational View (CARV)', to significantly reduce the risk for rotational malalignment and to test its clinical feasibility.

METHODS

A cadaver and clinical feasibility study was conducted to develop the CARV-technique, that included a standardized intraoperative fluoroscopy sequence of predefined landmarks on the uninjured and injured leg in which the rotation of the C-arm was used to verify for rotational alignment. A mid-shaft tibia fracture was simulated in a cadaver and an unlocked intramedullary-nail was inserted. Random degrees of rotational malalignment were applied using a hand-held goniometer via reference wires at the fracture site. Ten surgeons, blinded for the applied rotation, performed rotational corrections according to (1) current clinical practice after single-leg and dual-leg draping, and (2) according to the CARV-protocol. The primary outcome measure was the accuracy of the corrections relative to neutral tibial alignment. The CARV-protocol was tested in a small clinical cohort.

RESULTS

In total, 180 rotational corrections were performed by 10 surgeons. Correction according to clinical practice using single-leg and dual-leg draping resulted in a median difference of, respectively, 10.0° (IQR 5.0°) and 10.0° (IQR 5.0°) relative to neutral alignment. Single-leg and dual-leg draping resulted in malalignment (≥10°) in, respectively, 67% and 58% of the corrections. Standardized correction using the CARV resulted in a median difference of 5.0° (IQR 5.0°) relative to neutral alignment, with only 12% categorized as malalignment (≥10°). The incidence of rotational malalignment after application of the CARV decreased from 67% and 58% to 12% (p =  <0.001). Both consultants and residents successfully applied the CARV-protocol. Finally, three clinical patients with a tibial shaft fracture were treated according to the CARV-protocol, resulting all in acceptable alignment (<10°) based on postoperative CT-measurements.

CONCLUSION

This study introduces an easy-to-use and clinically feasible standardized intraoperative fluoroscopy protocol coined 'C-arm rotational view (CARV)' to minimize the risk for rotational malalignment following intramedullary-nailing of tibial shaft fractures.

Radiographic cortical thickness parameters as predictors of rotational alignment in proximal tibial shaft fractures: a cadaveric study

AIM

The treatment of tibial fractures with an intramedullary nail is an established procedure. However, torsional control remains challenging using intraoperatively diagnostic tools. Radiographic tools such as the Cortical Step Sign (CSS) and the Diameter Difference Sign (DDS) may serve as tools for diagnosing a relevant malrotation. The aim of this study was to investigate the effect of torsional malalignment on CSS and DDS parameters and to construct a prognostic model to detect malalignment.

METHODS

A proximal tibial shaft fracture was set in human tibiae. Torsion was set stepwise from 0° to 30° in external and internal torsion. Images were obtained with a C-arm and transferred to a PC for measuring the medical cortical thickness (MCT), lateral cortical thickness (LCT), tibial diameter (TD) in AP and the anterior cortical thickness (ACT) as well as the posterior cortical thickness (PCT) and the transverse diameter (TD) of the proximal and the distal main fragment.

RESULTS

There were significant differences between the various degrees of torsion for each of the absolute values of the examined variables. The parameters with the highest correlation were TD, LCT and ACT. A model combining ACT, LCT, PCT and TD lateral was most suitable model in identifying torsional malalignment. The best prediction of clinically relevant torsional malalignment, namely 15°, was obtained with the TD and the ACT.

CONCLUSION

This study shows that the CSS and DDS are useful tools for the intraoperative detection of torsional malalignment in proximal tibial shaft fractures and should be used to prevent maltorsion.

Intraoperative torsion control using the cortical step sign and diameter difference in tibial mid-shaft fractures

AIM

Intramedullar nailing of tibial mid-shaft fractures is a common surgical treatment. Fracture reduction, however, remains challenging and maltorsion is a common discrepancy which aggravates functional impairment of gait and stability. The use of radiographic tools such as the cortical step sign (CSS) and the diameter difference sign (DDS) could improve fracture reduction. Therefore, the validity of the CSS and DDS was analyzed to facilitate detection of maltorsion in tibial mid-shaft fractures.

METHODS

Tibial mid-shaft fractures were induced in human cadaveric tibiae according to the AO classification type A3. Torsional discrepancies from 0° to 30° in-/external direction were enforced after intramedullary nailing. Fluoroscopic-guided fracture reduction was assessed in two planes via analysis of the medical cortical thickness (MCT), lateral cortical thickness (LCT), tibial diameter (TD), anterior cortical thickness (ACT), posterior cortical thickness (PCT) and the transverse diameter (TD) of the proximal and distal fracture fragment.

RESULTS

The TD, LCT and ACT have shown a highly significant correlation to predict tibial maltorsion. While a model combining ACT, LCT, PCT and TD lateral was most suitable model to identify tibial maltorsion, a torsional discrepancy of 15°was most reliably detected with use of the TD and ACT.

CONCLUSION

The present study has shown, that maltorsion can be reliably assessed by the CSS and DDS during fluoroscopy. Thus, torsional discrepancies in tibial mid-shaft fractures can be most reliably assessed in the lateral plane by analysis of the LCT and TD.

Tibial tray rotation and posterior slope increase risk for outliers in coronal alignment

AIMS

The extensive variation in axial rotation of tibial components can lead to coronal plane malalignment. We analyzed the change in coronal alignment induced by tray malrotation.

METHODS

We constructed a computer model of knee arthroplasty and used a virtual cutting guide to cut the tibia at 90° to the coronal plane. The virtual guide was rotated axially (15° medial to 15° lateral) and with posterior slopes (0° to 7°). To assess the effect of axial malrotation, we measured the coronal plane alignment of a tibial tray that was axially rotated (25° internal to 15° external), as viewed on a standard anteroposterior (AP) radiograph.

RESULTS

Axial rotation of the cutting guide induced a varus-valgus malalignment up to 1.8° (for 15° of axial rotation combined with 7° of posterior slope). Axial malrotation of tibial tray induced a substantially higher risk of coronal plane malalignment ranging from 1.9° valgus with 15° external rotation, to over 3° varus with 25° of internal rotation. Coronal alignment of the tibial cut changed by 0.07° per degree of axial rotation and 0.22° per degree of posterior slope (linear regression, R² > 0.99).

CONCLUSION

While the effect of axial malalignment has been studied, the impact on coronal alignment is not known. Our results indicate that the direction of the cutting guide and malalignment in axial rotation alter coronal plane alignment and can increase the incidence of outliers. Cite this article: Bone Joint J 2020;102-B(6 Supple A):43-48.

Outcomes Following Open Reduction and Internal Fixation in Proximal Phalangeal Fracture with Rotational Malalignment

Background: The rotational malalignment in proximal phalanx fracture is unacceptable. Authors attempted to describe clinical and radiographic outcomes as well as complications after open reduction and internal fixation with screw only or plate for phalangeal fractures accompanied by rotational malalignment. Methods: Authors conducted a retrospective review of 46 patients who had been treated between Jan. 2010 and Dec. 2016. The average follow-up period was 16.7 months. A total active motion (TAM), Disability of Arm, Shoulder and Hand score (DASH), and tip pinch power between thumb and fractured finger were measured at the final follow-up. Complications were investigated during the follow up. We assessed the amount of rotation by measuring angle between 3rd ray and fractured finger. The measurement was divided into two groups depending on rotation direction, divergent and convergent direction group. Results: Twenty-eight cases were fixed with mini LCP plate, 12 cases with lag screws, and rest 6 cases with combined. All patients showed solid bony union on radiographs on average follow-up of 68 days (range, 41-157 days). Average TAM of the injured finger was 244 degrees and average DASH score was 4.9 at the last follow-up. Tip pinch power was 3.2 kg, which was not significantly different from that of the contralateral side at 3.4 kg (p = 0.21). The preexisting rotational angle was significantly adjusted (overall, 11.1°). Depending on rotation direction, preoperative 21.7° to postoperative 12.1° in 27 patients of convergent group and preoperative -5.0° to postoperative 8.3° in 19 patients of divergent group were achieved. Conclusions: The rotation from proximal phalanx fractures could be corrected with anatomic reduction by open reduction. Our results showed that open reduction and rigid internal fixation after physical examination for acute proximal phalanx fractures accompanied by rotational malalignment could achieve good clinical results.

Good Outcomes of Combined Femoral Derotation Osteotomy and Medial Retinaculum Plasty in Patients with Recurrent Patellar Dislocation

Objectives

To report the clinical outcomes of combined femoral derotation osteotomy and medial retinaculum plasty for recurrent patellar dislocation in patients with excessive femoral anteversion.

Methods

From January 2015 to March 2018, 20 knees in 20 patients (18 female, 2 male) with a mean age of 21 ± 4.2 years (range, 16 to 28 years) were retrospectively reviewed. All patients had undergone femoral derotation osteotomy and medial retinaculum plasty for recurrent patellar dislocation and excessive femoral anteversion angle (FAA > 25°). CT and X‐rays were used to assess the correction of the femoral anteversion angle, the tibia tuberosity‐trochlear groove (TT‐TG) distance, patellar tilt, and the congruence angle following the combinatory operations. Subjective scores, such as Kujala, International Knee Documentation Committee (IKDC), Tegner, and visual analogue scale (VAS) scores, were used to evaluate knee function preoperatively and postoperatively.

Results

No recurrence of patellar dislocation occurred in these patients during an average of 18 months (range, 12 to 23 months) of follow‐up. The mean of the FAA was corrected to 15.80° ± 3.58° postoperatively compared with 31.42° ± 4.95° preoperatively (P < 0.001). The TT‐TG distance was decreased from 22.17 ± 5.28 mm before surgery to 19.42 ± 4.57 mm after surgery (P = 0.03). The patellar tilt and congruence angle were improved from 30.43° ± 5.30°, 43.30° ± 11.04° to 15.80° ± 3.94°, 16.64° ± 9.98°, respectively (P < 0.001). The Kujala score was improved from 72.4 ± 19.90 before the surgery to 88.2 ± 12.25 after the surgery (P < 0.001). The IKDC score was improved from 70.56 ± 21.44 to 90.78 ± 14.32, and the VAS score was decreased from 4.23 ± 2.11 preoperatively to 1.27 ± 1.08 postoperatively (P < 0.001). No significant difference in Tegner score (5.46 ± 2.49 vs 5.79 ± 1.44) was found before and after the surgery (P = 0.2). Patients younger than 20 years old had lower Kujala (83.46 ± 14.56 vs. 90.84 ± 7.74, P = 0.02) and IKDC (83.49 ± 17.35 vs 92.46 ± 9.28, P = 0.04) scores than those older than 20 years.

Conclusion

Good knee function, pain relief, and improved patellofemoral congruence were achieved with the combined femoral derotation osteotomy and medial retinaculum plasty. The combined operations serve as an ideal treatment for recurrent patellar dislocation and address the primary risk factors.

Standardization of torsional CT measurements of the lower limbs with threshold values for corrective osteotomy

INTRODUCTION

Re-establishing anatomic rotational alignment of shaft fractures of the lower extremities remains challenging. Clinical evaluation in combination with radiological measurements is important in pre- and post-surgical assessment. Based on computed tomography (CT), a range of reference values for femoral torsion (FT) and tibial torsion (TT) have historically been reported, which require standardization to optimize the significant intra- and inter-observer variability. The aims of this study were (re-)evaluation of the reference FT and TT angles, determination of the normal intra-individual side-to-side torsional differences to aid the surgical decision-making process for reoperation, and development of a novel 3D measurement method for FT.

MATERIALS AND METHODS

In this retrospective study, we included 55 patients, without any known torsional deformities of the lower extremities. Two radiologists, independently, measured the rotational profile of the femora using the Hernandez and Weiner CT methods for FT, and the tibiae using the bimalleolar method for TT. The intra-individual side-to-side difference in paired femora and paired tibiae was determined. A 3D technique for FT assessment using InSpace^® was designed.

RESULTS

FT and TT demographic values were lower than previously reported, with mean FT values of 5.1°-8.8° and mean TT values of 25.5°-27.7°. Maximal side-to-side differences were 12°-13° for FT and 12° for TT. The Weiner method for FT was less variable than the Hernandez method. The new 3D method was equivocal to the conventional CT measurements.

CONCLUSION

The results from this study showed that the maximal side-to-side tolerance in asymptomatic normal adult lower extremities is 12°-13° for FT and 12° for TT, which could be a useful threshold for surgeons as indication for revision surgery (e.g., derotational osteotomy). We developed a new 3D CT method for FT measurement which is similar to 2D and could be used in the future for virtual 3D planning.

Bilateral Low-Dose Computed Tomography Assessment for Post-Operative Rotational Malalignment After Intramedullary Nailing for Tibial Shaft Fractures: Reliability of a Practical Imaging Technique

INTRODUCTION

The purpose of this study is to evaluate the intra- and inter-observer reliability of low-dose protocolled bilateral postoperative Computed Tomography (CT)-assessment of rotational malalignment after intramedullary nailing (IMN) of tibial shaft fractures.

MATERIALS AND METHODS

156 patients were prospectively included with tibial shaft fractures that were treated with IMN in a Level-I Trauma Centre. All patients underwent post-operative bilateral low-dose CT-assessment (effective dose of 0.03784 - 0.05768 mGy) as per hospital protocol. Four observers performed the validated reproducible measurements of tibial torsion in degrees, based on standardized techniques. The Intra-Class Coefficient (ICC) was calculated to evaluate intra- and inter-observer reliability. The intra- and inter-observer reliability was categorized according to Landis and Koch.

RESULTS

Intra-observer reliability for quantification of rotational malalignment on post-operative CT after IMN of tibial shaft fractures was excellent with 0.95 (95% CI = 0.92-0.97). The overall inter-observer reliability was 0.90 (95% CI = 0.87-0.92), also excellent according Landis and Koch.

CONCLUSION

Firstly, bilateral post-operative low-dose -similar radiation exposure as plain chest radiographs- CT assessment of tibial rotational alignment is a reliable diagnostic imaging modality to assess rotational malalignment in patients following IMN of tibial shaft fractures and it allows for early revision surgery. Secondly, it may contribute to our understanding of the incidence-, predictors- and clinical relevance of post-operative tibial rotational malalignment in patients treated with IMN for a tibial shaft fracture, and facilitates future studies on this topic.

A study of anatomy of distal femur pertaining to total knee replacement: an analysis, conclusions and recommendations

BACKGROUND

Multiple landmarks including the transepicondylar axis (TEA), posterior condylar axis (PCA) and anterior trochlear line (TL) have been used to set up the femoral component rotation, but each is faced with its own practical obstacle that limits its usage. Also a common practice is to set the femoral component rotation at 3° external rotation to PCA and valgus resection angle at 5°-7° to anatomical axis of femur. For the reason that the anatomy of each knee is different, it may not be justified to practice such a set protocol in all cases. The aim of the study was to compare the anatomical landmarks used to set up the femoral component rotation and to study the variability in the different anatomical relationships relevant to total knee replacement.

MATERIALS AND METHODS

The study had 52 patients (94 knees) with grade IV osteoarthritis. Full-length lower limb scanogram and 1 mm cross-sectional cuts of distal femur were taken. aTEA, sTEA, PCL, TL, CTA, PCA, TLA and valgus angles were taken for all knees.

RESULTS

aTEA is identifiable in all cases but sTEA in only 59 knees (62.77%). Correspondingly, CTA is calculable in all knees and PCA in 62.77% cases. Mean CTA and mean PCA were 5.4° ± 1.88° SD and 0.71° ± 1.95° SD, respectively. Mean angle between aTEA and sTEA was 4.88. TL is a line difficult to draw because of high incidence of anterior osteophytes, making CTA a more reliable parameter than TLA. Mean TLA was 10.31° ± 3.52° SD. Mean valgus resection angle was 4.86° ± 2.53° SD. Gender- or side-based differences in any of these values were not statistically different.

CONCLUSIONS

Using aTEA or sTEA can make a big difference in femoral component rotation; therefore, whether aTEA or sTEA should be used needs to be further investigated. CTA, PCA and valgus resection angle need to be individually calculated for each knee. Use of TLA is not recommended.

Femoral malrotation after surgical treatment of femoral shaft fractures in children: a retrospective CT-based analysis

BACKGROUND

Rotational malalignment is an important and not always avoidable complication after surgical treatment of femoral shaft fractures. The purpose of this study was to determine the incidence of rotational malalignment in children after surgical treatment of femoral shaft fractures and to identify potential patient- and treatment-related risk factors based on data obtained from CT scans.

METHODS

We conducted a retrospective analysis of all patients aged less than 15 years with femoral shaft fractures admitted to our level 1 trauma centre between January 2004 and July 2014. Patients having obtained postoperative CT scans were included for the determination of rotational malalignment. A difference of greater than 15° in femoral torsion between both legs was considered as clinically relevant. Additionally, demographic data and clinical information such as fracture type, treatment method, fluoroscopy time and operating time were reviewed.

RESULTS

A total of 24 patients were enrolled in this study. Clinically relevant femoral malrotation was identified in 10 patients (41.6%). Surgical revision was performed in 7 patients (29.2%). There was no association between the type of surgical procedure, age and the incidence and/or amount of femoral malrotation.

CONCLUSIONS

The data suggest that relevant femoral malrotation is an evident problem after surgical treatment of femoral shaft fractures in children that requires critical postoperative assessment.

LEVEL OF EVIDENCE

Level III, retrospective study.

Malalignment after minimally invasive plate osteosynthesis in distal femoral fractures

INTRODUCTION

Although minimally invasive plate osteosynthesis (MIPO) is a preferred operative treatment for fractures of the distal femur, malalignment is a significant concern because of indirect reduction of the fracture. The purpose of this study, therefore, was to evaluate radiologic alignment after MIPO for distal femoral fractures.

PATIENTS AND METHODS

Of the 138 patients with fracture of the distal femur who underwent MIPO, we enrolled 51 patients in whom bilateral rotational alignment could be assessed by postoperative computed tomography (CT). The patients included 32 men and 19 women, with a mean age of 54.3 years. Thirteen patients had femoral shaft fractures (according to the AO/OTA classification: 32-A, n=2; 32-B, n=6; 32-C, n=5), whereas 38 patients had distal femoral fractures (33-A, n=7; 33-C, n=31). Coronal and sagittal alignments were assessed using simple radiography, whereas rotational alignment was assessed using CT. According to the difference between the affected and unaffected sides, we divided the patients into satisfactory and unsatisfactory groups (reference point of 8°, using Handolin's classification). Thereafter, we determined which factors can lead to malalignment, including fracture location (distal femoral shaft fracture or metaphyseal fracture), fracture pattern (simple fracture, n=15; complex fractures, n=36 patients), coronal and sagittal alignments, and combined ipsilateral long bone fractures.

RESULTS

Coronal and sagittal alignment were satisfactory in 96.2% (average, 2.8°) and 98% (average, 2.2°), respectively, whereas the rotational alignment was satisfactory in 56.9% of patients. Leg length discrepancy was satisfactory in 92.3% of the patients (average, 10.9mm). Concerning rotational malalignment, an unsatisfactory result was obtained in 48.6% of subjects with complex fractures and 26.7% of subjects with simple fractures (p=0.114). No significant correlation was noted between the angular deformity in the coronal and sagittal planes and the degree of rotational alignment (p=0.607 and 0.774, respectively).

CONCLUSIONS

Regardless of the fracture pattern, rotational malalignment may occur at an extremely high rate after MIPO for fractures of the distal femur.

Influence of tibial rotation in total knee arthroplasty on knee kinematics and retropatellar pressure: an in vitro study

PURPOSE

Although continuous improvements have been made, there is still a considerable amount of unsatisfied patients after total knee arthroplasty (TKA). A main reason for this high percentage is anterior knee pain, which is supposed to be provoked by post-operative increased retropatellar peak pressure. Since rotational malalignment of the implant is believed to contribute to post-operative pain, the aim of this study was to examine the influence of tibial component rotation on knee kinematics and retropatellar pressure.

METHODS

Eight fresh-frozen knee specimens were tested in a weight-bearing knee rig after fixed-bearing TKA under a loaded squat from 20° to 120° of flexion. To examine tibial components with different rotations, special inlays with 3° internal rotation and 3° external rotation were produced and retropatellar pressure distribution was measured with a pressure-sensitive film. The kinematics of the patella and the femorotibial joint were recorded with an ultrasonic-based motion analysis system.

RESULTS

Retropatellar peak pressure decreased significantly from 3° internal rotation to neutral position and 3° external rotation of the tibial component (8.5 ± 2.3 vs. 8.2 ± 2.4 vs. 7.8 ± 2.5 MPa). Regarding knee kinematics femorotibial rotation and anterior-posterior translation, patella rotation and tilt were altered significantly, but relative changes remained minimal.

CONCLUSION

Changing tibial rotation revealed a high in vitro influence on retropatellar peak pressure. We recommend the rotational alignment of the tibial component to the medial third of the tibial tuberosity or even more externally beyond that point to avoid anterior knee pain after TKA.

Does MIPO of fractures of the distal femur result in more rotational malalignment than ORIF? A retrospective study

PURPOSE

Intraoperative control of rotational malalignment poses a big challenge for surgeons when using modern MIPO (minimally invasive plate osteosynthesis) techniques. We hypothesized that distal femoral fractures treated with MIPO technique are more often fixed in malrotation than those treated with open reduction internal fixation (ORIF).

METHODS

In this retrospective study, we identified 20 patients who met the inclusion criteria and agreed to take part in the study. In ten patients MIPO was applied, in the other ten ORIF was used. Mean age was 44.8 (19-71 years). Functional status was assessed using clinical scores (Harris Hip Score, WOMAC Hip, KS Score, WOMAC Knee, Kujala Score). Rotational alignment was assessed with magnetic resonance imaging and compared to the opposite leg.

RESULTS

We discovered a significant difference in the mean rotational difference between the MIPO group (14.3°) and the ORIF group (5.2°). Functionally, patients in the ORIF group outperformed patients in the MIPO group in all clinical scoring systems although no one proved to be statistically significant. MIPO technique was associated with significantly more rotational malalignment compared to ORIF in distal femur fracture fixation. However, implant failure and nonunion was more common in the ORIF group, with a revision rate of 3 versus 1 in the ORIF group. Clinical scoring did not significantly different between both groups.

CONCLUSION

Taking into account the undisputable advantages of minimally invasive surgery, improved teaching of methods to avoid malrotation as well as regular postoperative investigations to detect any malrotation should be advocated.