Subcutaneous internal anterior fixation of pelvis fractures—which configuration of the InFix is clinically optimal?—a retrospective study

A Comparative Study of Functional Outcomes in Unstable Pelvic Ring Fractures Treated With Internal Fixator (INFIX) With and Without Sacroiliac Joint Screw Fixation

Introduction Despite constituting only 3-8% of orthopedic trauma cases, pelvic injuries are associated with high mortality rates, emphasizing the critical need for stable fixation rather than merely anatomical alignment. The use of an anterior, subcutaneous, internal pelvic fixator (INFIX), a novel technique, has shown promise in treating these injuries. Posterior pelvic ring injuries are challenging because they require a significant level of surgical training and technical expertise, and each treatment method has disadvantages. The aim of this study is to compare the clinical and biomechanical outcomes of INFIX with and without sacroiliac screw fixation for unstable pelvic fractures. Methods and methodology Retrospectively, we selected 20 patients with unstable pelvic ring injuries who had come to a high-volume tertiary care hospital and medical college in the state of Maharashtra, India. All the patients were operated on with INFIX; 10 with a sacroiliac joint screw and 10 without a sacroiliac joint screw. We followed up with the patients for six months and evaluated them according to the Majeed score. Results Functional outcomes differed little between INFIX patients operated on with and without a sacroiliac joint screw. However, morbidity, hospital stay, the need for ICU, radiation exposure, and technical ease of surgery were improved in INFIX patients without the sacroiliac screw procedure. We noted an average Majeed score of 78 in the INFIX-alone group and 77.2 in the group that received INFIX with a sacroiliac joint screw. Six months after the surgery, the patients showed signs of a stable bony union, had achieved a full range of motion, and reported no problems in their day-to-day work. Conclusion Although this was a short-term study, we conclude that INFIX without a sacroiliac joint screw showed a comparable functional outcome compared to INFIX with a sacroiliac joint screw. Patients with INFIX alone showed better results; they had reduced surgical time, reduced radiation exposure, and less evidence of neurological harm to the L5-S1 nerve root. The procedure was less complicated and easier for surgeons to learn. Its simplicity and speed were especially beneficial for obese patients.

Functional Outcome of Internal Fixation (INFIX) in Anterior Pelvic Ring Fractures

Introduction Pelvic injuries account for 2% of all orthopedic admissions and are associated with high mortality rates. They need a stable fixation and not an anatomical fixation. Hence, the role of internal fixation (INFIX) comes into play, which provides a stable internal fixation without the complication of open reduction and external fixation with plates and screws. Materials and methodology Thirty-one patients with unstable pelvic ring injuries coming to a tertiary care hospital in the state of Maharashtra, India, were selected retrospectively. They were operated on with INFIX. Patients were followed up for a period of six months and evaluated according to the Majeed score. Results There was a significant functional outcome in patients operated on with INFIX in pelvic ring injuries in terms of the ability to sit, stand, rejoin work, take part in sexual intercourse, and bear pain. An average Majeed score of 78 with signs of a stable bony union by six months and a full range of motion was noticed in most patients with no problems in day-to-day work. Conclusion INFIX provides stable internal fixation of pelvic fractures with good functional outcome without the disadvantages of external fixation or open reduction with plates.

Identification of safe channels for screws in the anterior pelvic ring fixation system

Background

Minimally invasive surgery for pelvic fracture using anterior ring internal fixator system is increasing gradually, and the way to insert the fixation screws in the fixation system is the key technical points of the method. However, there have been few studies on insertion of fixation screws for the anterior pelvic ring internal fixator system.

Objective

To identify safe channels for fixation screws in the anterior pelvic fixator system and provide the anatomical basis for insertion of fixation screws in clinical operation.

Methods

Screw insertion was simulated into a total of 40 pelvic finite element models as well as 16 fresh pelvic specimens, and the channel parameters were measured.

Results

Finite elements (male, female) include: screws in ilium: length 114.4 ± 4.1 and 107.6 ± 8.3 mm, respectively; diameter 11.7 ± 0.5 and 10.0 ± 0.6 mm, distance between screw and anterior inferior iliac spine: 5.5 ± 1.0 and 5.6 ± 1.0 mm, angle of coronal plane 55.8° ± 2.4° and 50.6° ± 3.1°, angle of sagittal plane 26.6° ± 1.0° and 24.5° ± 1.9° and angle of horizontal plane 64.9 ± 3.7 and 58.1 ± 3.1; screws in pubis: length 47.0 ± 2.0 and 39.8 ± 3.9 mm, diameter 7.1 ± 0.4 and 6.1 ± 0.4 mm. Specimens (male, female) include: distance between screw and anterior inferior iliac spine: 5.5 ± 0.5 and 5.6 ± 0.7 mm, angle of coronal plane 55.9° ± 1.3° and 50.7° ± 1.5°, angle of sagittal plane 26.7° ± 0.5° and 24.1° ± 0.9° and angle of horizontal plane 64.8° ± 0.6° and 58.8° ± 0.8°. In the comparison between female and male in each group, differences in distances between screws and anterior inferior iliac spine and median line of symphysis pubis (P > 0.05) were not statistically significant; differences in the remaining parameters were statistically significant (P < 0.05).

Conclusions

If surgeons paid attention to sex differences, select screws of appropriate diameter and length and hold the insertion position and direction, screws in the anterior pelvic ring fixation system could be safely inserted.

Variability in rod to bone distance needed in pelvic subcutaneous internal fixation to avoid nerve compression: A tridimensional population-based study

INTRODUCTION

Pelvic internal fixation has become a popular method for treatment of unstable pelvic ring injuries. Although successful, one complication is femoral nerve palsy from compression of the connecting rod. In light of this complication, this study was designed to evaluate sagittal inclinations of the rod and the feasibility of using a rod with a constant curvature.

HYPOTHESIS

It is hypothesized that that there is a connection between the sagittal inclination of the rod and the rod to bone distance, as well as single rod can be contoured with a constant curvature to be used in the majority of all patients.

METHODS

Three dimensional models of pelvis CTs from a single level 1 trauma center were created and imported into a program where software superimposed a pre-contoured rod in the sagittal planes upon the pelvic slices. The sagittal inclination was deemed acceptable is no interference occurred between the area of compression risk and the rod. For each pelvis and considered sagittal rod inclination, the rod radius of curvature (ROC), minimal rod to bone distance (RTB) and transverse inclinations (φ_L and φ_R) were measured at which the pedicle screws should be inserted to follow the direction of the smallest RTB.

RESULTS

The sagittal inclinations feasible for all subjects were between 15° to 30°. In this sagittal range, the average RTB varied in values ranging from 4.0±0.9mm to 25.4±11.4mm (p<0.01). Only 46% of subjects allowed a rod with constant curvature.

DISCUSSION AND CONCLUSION

Our study found that a rod to bone distance of 15mm was not safe for all models. As well, many subject models did not allow placement of pre-contoured rod. Patient specific templating of pelvic subcutaneous internal fixation is strictly needed to limit complications.

LEVEL OF EVIDENCE

VII; Basic Science.

Outcomes and complications of the INFIX technique for unstable pelvic ring injuries with high-velocity trauma: a systematic review and meta-analysis

BACKGROUND

The pelvic INFIX technique has been proposed as a useful alternative to symphyseal plating for management of unstable pelvic ring injuries. The minimally invasive nature of the procedure, shorter operative time and less perioperative blood loss have been purported as potential advantages.

QUESTIONS/PURPOSES

This systematic review and meta-analysis were conducted to determine the outcomes and complications of the INFIX technique for unstable pelvic ring injuries.

METHODS

A systematic review of literature was performed on the PubMed, EMBASE and Scopus databases. Prospective and retrospective studies in all languages, whether comparative or non-comparative, pertaining to the use of INFIX in pelvic fractures were included. Studies which did not evaluate INFIX, case reports, conference abstracts and those with less than 10 cases were excluded. Cadaveric studies, technique papers and studies that did not describe the prespecified outcome measures were also excluded. Meta-analysis consisted of two different arms: a comparative arm, to compare INFIX to symphyseal plating, and a non-comparative meta-analysis arm, to determine pooled rates of outcomes and complications. Risk of bias was determined by the Methodological Index for Non-Randomised Studies (MINORS) tool.

RESULTS

A total of 22 studies were included in the systematic review, of which 7 were comparative and 15 were non-comparative. 746 patients were included for qualitative analysis and pooled analysis done for 589 patients. The average follow-up of these studies ranged from a minimum of 5.4 months to a maximum of 54 months. Comparative meta-analysis (n = 3 studies) of plating and INFIX showed significantly lesser blood loss (mean difference = 176.46 mL; 95% CI - 207.54 to - 145.38) and shorter operative time (mean difference = 26.43 min, 95% CI - 31.79 to - 21.07) with INFIX, but no significant difference in the overall complication rates (OR 1.59, 95% CI 0.83-3.05) and functional outcome scores (mean difference = - 2.51, 95% CI - 5.73 to 0.71). Pooled analysis showed overall good radiological (mean percentage of excellent to good reduction = 91.4%, 95% CI 0.860-0.969) and functional outcomes (mean Majeed score = 86.48, 95% CI 83.34-89.61) with INFIX. The most common complications were lateral femoral cutaneous nerve (LFCN) injury (overall rate 28%, 95% CI 15.1-41%) and heterotopic ossification (HO) (overall rate 9.4%, 95% CI 5.5-13.3%); rates of other complications were low. Significant heterogeneity was noted in the pooled analysis of blood loss, operative time, functional outcome, HO and LFCN injury. The overall strength of evidence was found to be weak.

CONCLUSION

The INFIX technique can be considered as a viable alternative to symphyseal plating for unstable pelvic ring injuries. It has the advantages of shorter operative times and less blood loss, along with comparable functional outcomes, when compared to plating. Overall, good functional outcomes can be expected. However, well-designed, multi-center randomized controlled trials are needed to conclusively prove the benefit of this technique.

Modified pedicle screw-rod versus anterior subcutaneous internal pelvic fixation for unstable anterior pelvic ring fracture: a retrospective study and finite element analysis

Objectives

This study compared the stability and clinical outcomes of modified pedicle screw-rod fixation (MPSRF) and anterior subcutaneous internal pelvic fixation (INFIX) for the treatment of anterior pelvic ring fractures using the Tornetta and Matta grading system and finite element analyses (FEA).

Methods

In a retrospective review of a consecutive patient series, 63 patients with Orthopaedic Trauma Association (OTA)/Arbeitsgemeinschaft für Osteosynthesefragen (AO) type B or C pelvic ring fractures were treated by MPRSF (n = 30) or INFIX (n = 33). The main outcome measures were the Majeed score, incidence of complications, and adverse outcomes, and fixation stability as evaluated by finite element analysis.

Results

Sixty-three patients were included in the study, with an average age of 34.4 and 36.2 in modified group and conventional group, respectively. Two groups did not differ in terms of the injury severity score, OTA classification, cause of injury, and time to pelvic surgery. However, the MPSRF group had a rate of higher satisfactory results according to the Tornetta and Matta grading system than the conventional group (73.33% vs 63.63%) as well as a higher Majeed score (81.5 ± 10.4 vs 76.3 ± 11.2), and these differences were statistically significant at 6 months post-surgery. FEA showed that MPSRF was stiffer and more stable than INFIX and had a lower risk of implant failure.

Conclusions

Both MPSRF and INFIX provide acceptable biomechanical stability for the treatment of unstable anterior pelvic ring fractures. However, MPSRF provides better fixation stability and a lower risk of implant failure, and can thus lead to better clinical outcomes. Therefore, MPSRF should be more widely applied to anterior pelvic ring fractures

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02618-9.

Minimally invasive internal fixation for unstable pelvic ring fractures: a retrospective study of 27 cases

Background

This study aimed to evaluate the radiographic and clinical outcomes of anterior subcutaneous internal fixation (INFIX) with or without posterior fixation for the treatment of unstable pelvic fractures.

Methods

Intraoperative blood loss, operation time, and duration of hospital stay were recorded, and fracture union and postoperative complications were evaluated. The fracture reduction quality was evaluated using the Matta score, pelvic deformity index (PDI), and pubic symphyseal width (PSW). In addition, the functional recovery and general quality of life were evaluated using the Majeed score and the 12-Item Short-Form Survey (SF-12), respectively. Furthermore, sacral nerve injury was evaluated using the Gibbons classification.

Results

Twenty-seven patients (14 males and 13 females) with an average age of 37.4 years were followed up for a mean of 22 months. The average operation time, median intraoperative blood loss, and average duration of hospital stay were 129 ± 47 min, 100 mL, and 22 ± 13 days, respectively. All patients achieved bony union with an average union time of 13.3 weeks. Furthermore, the average PDI and PSW were 0.07 ± 0.04 vs. 0.04 ± 0.03 (P = 0.009) and 1.15 ± 1.36 vs. 0.54 ± 0.17 (P = 0.048) before and after the operation, respectively. In 78% of the patients, the Matta or Majeed scores were excellent or good. The SF-12 physical and mental health scores were 45.1 ± 10.2 and 53.2 ± 6.3, respectively. Furthermore, one superficial surgical site infection, one loosening of INFIX, one lateral femoral cutaneous nerve irritation, one femoral nerve injury, and two implant discomforts due to the bar were noted. Among five patients with sacral nerve injuries, four were asymptomatic, and one just had paresthesia at the last follow-up.

Conclusion

INFIX with or without sacroiliac screws can achieve satisfactory radiographic and functional outcomes in the treatment of unstable pelvic ring fractures.

Trial registration

ChiCTR2000038812. Registered 04 October 2020. Retrospectively registered.

INFIX-safe and effective surgical option for complex fracture patterns of the anterior pelvic ring: A prospective single center study

Background

Complex fracture patterns of anterior pelvic ring are a challenge and usually needs extensive surgeries. The purpose of this study was to evaluate INFIX as a minimally invasive procedure for such injuries in terms of feasibility, outcomes and complications in the Indian population.

Methods

Patients with complex fracture patterns of anterior pelvic ring were selected for anterior INFIX application along with standard posterior stabilization. Outcomes were assessed radiographically by Matta's criteria and amount of displacement. Post-operative CT scan for relation of implant to vital structures and Doppler at varying hip flexion for possible vascular occlusion was used. Functional outcomes included both disease specific scores (Majeed score, IOWA pelvic score) and quality of life scores (SMFA, SF-12). Complications were also noted.

Results

12 cases out of 112 patients had complex fracture pattern of the anterior ring. Most common injury pattern were LC-3 and VS (n = 6 and 3) Young and Burgess type. The average follow up was 6 months. Fracture reduction as per Matta's criteria was excellent in 10 (83.3%) cases and good in 2 (16.6%) cases with functional outcomes excellent in 11 cases, and a mean Majeed score of 92.67 ± 5.8. The average SMFA score was 51 ± 4.39 and mean SF-12 scores for physical and mental health were 48.493 ± 6.74 and 56.370 ± 4.04 respectively. Complications noted were lateral femoral cutaneous nerve palsy (1/24 nerves), skin dehiscence (n = 2), infection (n = 2) and sacral nonunion (n = 1).

Conclusion

INFIX is a safe and effective minimally invasive technique for addressing complexfracture patterns involving the anterior half of pelvic ring with excellent fracture reduction, radiological and functional outcomes and predictable fracture healing.

[Research progress on minimally invasive treatment of anterior pelvic ring fracture]

OBJECTIVE

To summarize the related research results of minimally invasive treatment of anterior pelvic ring fracture, and to improve the understanding of minimally invasive treatment of anterior pelvic ring fracture.

METHODS

The literature of minimally invasive treatment of anterior pelvic ring fracture at domestic and overseas in recent years was reviewed, and the reduction and fixation methods of minimally invasive treatment were summarized and analyzed.

RESULTS

The pelvic reduction frame may be an effective auxiliary method for minimally invasive reduction of pelvis. The fixation methods of anterior pelvic ring include percutaneous screw fixation, stent fixation, and percutaneous plate fixation.

CONCLUSION

One kind of fixation is not applicable to all types of anterior pelvic ring fracture, and the fixation method should be selected according to the type of fracture and the patient's condition to minimize the complications.

Safe Supra-Acetabular Pin Insertion in Relation to Intraosseous Depth

In pelvic fractures, dysfunction of the pelvic ring is often stabilized with supra-acetabular pin insertion. In existing literature, there are heterogeneous indications on proper pins selection and inclinations. Therefore, this study aimed to quantify the narrowing of safe pin corridors in the transverse and sagittal planes with increments of intraosseous screw depths. A computer algorithm created cross-sections over three-dimensional pelvic reconstructions at sagittal inclinations from 45° cranial to 45° caudal in 5° increments. Templates of screw depths spanning 60-120 mm in 15 mm increments were disposed in the transverse plane from 45° medial to 45° lateral. Each intraosseous screw depth and transverse angle were evaluated for intraosseous containment to evaluate ranges narrowing with increasing screw depths. The 60-mm depth resulted in the largest sagittal range (60.9° ± 6.9°) and transverse range (27.5° ± 4.1°) at 30° caudal. Increasing depths by 15 mm resulted in ranges being significantly different from one another (p < 0.01). The sagittal plane of 20° cranial had the highest frequency of insertion for all depths, while transverse ranges were narrowed (p < 0.01). Bisecting angles were similar for sagittal planes 20° cranial to 30° caudal with an average of 27.9° ± 1.2° (p ≥ 0.115). In conclusion, while 60 mm depths can be inserted with the highest discretion, 15 mm increments in depth significantly reduce safe ranges. Screws depths above 90 mm have low frequencies of insertion, should be inserted more cranially and must be considered prone to breaching. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1790-1797, 2019.

Modified internal fixator for anterior pelvic ring fractures versus conventional two-screw fixation

PURPOSE

The present study aims to evaluate the short-term clinical effects and complications of modified three-screw fixation and conventional two-screw fixation for treating anterior pelvic ring fractures.

METHODS

A retrospective study of 51 patients with type B fractures was performed. 25 patients (modified group) were treated with modified three-screw fixation and the other 26 patients (conventional group) with conventional two-screw fixation. Outcome measures included operation time, intraoperative blood loss, hospital stays, postoperative complications and the Majeed score at postoperatively 2 months, 3 months, 1 year and the time of implant removal.

RESULTS

The mean operative times and mean blood loss for modified three-screw fixation versus conventional two-screw fixation bilateral were 54.8 ± 10.7 min versus 32.3 ± 9.9 min, and 153.3 mL versus 550.0 mL (p < 0.001), respectively. However, the Majeed score was better in modified group at postoperatively 2 months (75.6 ± 9.5 vs. 69.7 ± 8.3, p = 0.008) and 3 months (80.3 ± 10.7 vs. 75.1 ± 11.9, p = 0.014). There was no statistical difference between two groups at the time of implant removal (82.1 ± 9.3 vs. 80.9 ± 8.8, p = 0.272) and postoperatively 1 year (83.5 ± 7.8 vs 82.6 ± 8.2, p = 0.723). No patients experienced surgical wound infection, deep vein thrombosis, delayed union or nonunion, implant loosening or rupture. One patient complained of tardive unilateral thigh pain at postoperatively 4 months in conventional group.

CONCLUSIONS

Both modified three-screw fixation and conventional two-screw fixation could ultimately afford satisfactory clinical and radiological outcomes with less complication for anterior pelvic ring fractures. The modified three-screw fixation might have better biomechanical strength and faster pelvic rehabilitation.

Conventional plate fixation versus minimally invasive modified pedicle screw-rod fixation for anterior pelvic ring fractures

There are various methods of fixation for anterior pelvic ring fractures. We report our experience with modified pedicle screw-rod fixation (MPSRF) via a minimally invasive method. Fourteen patients with anterior pelvic ring fracture were treated by internal fixation (conventional plate fixation, n = 7; MPSRF, n = 7). Intraoperative blood loss, operative time, post-operative fracture reduction grading by radiography, and complication rates were compared and statistically analyzed. Patients treated with MPSRF had a shorter operative time (-36 min, P = 0.378) and significantly less blood loss (-264 ml, P = 0.026) than patients in the conventional plate fixation group. Postoperative radiological evaluations were similar between the groups (P > 0.05). The complication rate was lower in the MPSRF group (1/7 patients) than in the plate fixation group (2/7 patients). Modified pedicle screw-rod fixation is a viable treatment for anterior pelvic ring fixation and can reduce blood loss.