Treatment Outcomes in Vertical Shear Pelvic Fractures: A Comparative Study.

Background Vertical shear (VS) pelvic ring injuries present a unique challenge due to their inherent vertical and rotational instability and the risk of massive bleeding. VS injuries may result from either bony or ligamentous injury. The goal in the treatment of VS fractures of the pelvis is to achieve and maintain an accurate reduction of the displaced hemipelvis. Aim of the study This study aimed to compare the results of the treatment of VS fractures pelvis by using iliosacral (IS) screws versus lumbopelvic fixation (LPF). Methodology This retrospective study was carried out on 40 patients with VS fracture pelvis injuries at El Hadara University Hospital, Alexandria, Egypt, from January 2020 to December 2020. Twenty of them were treated by an IS screw, and the other 20 were treated by LPF. Then, both groups were followed up for six months with regard to union rate, metal failure, and clinical outcomes. Results The EQ-5D showed a significant improvement in LPF more than the IS screw group in the five items of the score. Moreover, the total EQ-5D index showed a significant increase in the LPF group more than the IS screw group (p < 0.05). The incidence of neurological complication was found in four cases in the IS screw group, while no cases were found in the LPF group. The infection was found in six patients in the IS screw group and only three cases in the LPF group. The malunion was found in two cases in the IS screw group and no cases in the LPF group. The neurological change and the incidence of infection were significantly higher in the IS screw group than in the LPF group (p < 0.05). Conclusion Our results demonstrate reliable maintenance of reduction and acceptable complication rates with a minimally invasive LPF for VS fractured pelvis. The benefits of minimally invasive LPF may be offset by increased elective reoperations for the removal of instrumentation.

Biomimetic design and clinical application of Ti-6Al-4V lattice hemipelvis prosthesis for pelvic reconstruction.

OBJECTIVE: This study aims to biomimetic design a new 3D-printed lattice hemipelvis prosthesis and evaluate its clinical efficiency for pelvic reconstruction following tumor resection, focusing on feasibility, osseointegration, and patient outcomes. METHODS: From May 2020 to October 2021, twelve patients with pelvic tumors underwent tumor resection and subsequently received 3D-printed lattice hemipelvis prostheses for pelvic reconstruction. The prosthesis was strategically incorporated with lattice structures and solid to optimize mechanical performance and osseointegration. The pore size and porosity were analyzed. Patient outcomes were assessed through a combination of clinical and radiological evaluations. RESULTS: Multiple pore sizes were observed in irregular porous structures, with a wide distribution range (approximately 300-900 µm). The average follow-up of 34.7 months, ranging 26 from to 43 months. One patient with Ewing sarcoma died of pulmonary metastasis 33 months after surgery while others were alive at the last follow-up. Postoperative radiographs showed that the prosthesis's position was consistent with the preoperative planning. T-SMART images showed that the host bone was in close and tight contact with the prosthesis with no gaps at the interface. The average MSTS score was 21 at the last follow-up, ranging from 18 to 24. There was no complication requiring revision surgery or removal of the 3D-printed hemipelvis prosthesis, such as infection, screw breakage, and prosthesis loosening. CONCLUSION: The newly designed 3D-printed lattice hemipelvis prosthesis created multiple pore sizes with a wide distribution range and resulted in good osteointegration and favorable limb function.

Clinical outcomes in patients with neurological disorders following periacetabular tumor removal and endoprosthetic reconstruction of the hemipelvis.

Background: Surgical treatment of musculoskeletal tumors in the periacetabular region present extremely difficult due to the complex anatomy and need for reconstruction. Orthopedic surgeons face more difficulties in patients with neurological conditions, which can cause increased muscle tone, an elevated risk of fractures, and compromised bone quality. There is limited evidence regarding endoprosthetic reconstruction for periacetabular tumors in individuals with neurological disorders. Methods: We conducted a single-center retrospective study to examine the outcomes of patients with preexisting neurological conditions who underwent surgery to remove periacetabular tumors and who underwent endoprosthesis reconstruction. Clinical presentation, detailed neurological conditions, complications, and functional outcomes were studied. Results: Sixteen out of the 838 patients were identified (1.91%), with a mean follow-up time of 33 months. The primary neurological conditions encompassed Parkinson's disease, Alzheimer's disease, dementia, and cerebral ischemic stroke. Every patient was diagnosed with periacetabular lesions that were either primary or oligometastatic. They underwent tumor resection and subsequently received endoprosthetic reconstruction of the hemipelvis. Three patients developed metastasis lesions later, and two patients experienced tumor recurrence. Five cases experienced hip dislocation-one with periprosthetic fracture and one with surgical site infection. The position of the prosthetic rotating center was not correlated with dislocation. The reoperation rate was 31.25%. The cohort of patients all presented with more extended hospital stays and rehabilitation. In 3 patients, the general functional score was good, while in 6 patients, it was fair; in 7 patients, it was regarded as poor. The average MSTS93 score was 49.71%. Conclusion: Endoprosthetic reconstruction after periacetabular tumor resection is an effective way to eliminate tumors and salvage limbs. However, this group of patients has an increased likelihood of secondary surgery, complications, extended hospital stay, and no significant improvement in functional outcomes. Despite the diverse nature of the cohort, it is recommended to consider enhanced soft tissue reconstruction, supervised functional recovery and rehabilitation training.

What are the 2-year survivorship outcomes of custom hemipelvis reconstruction after hemipelvectomy and revision arthroplasty? The evolution of a custom ilium "monoflange".

BACKGROUND: Innovations in machined and three-dimensionally (3D) printed implant technology have allowed for customized complex pelvic reconstructions. We sought to determine the survivorship of custom hemipelvis reconstruction using ilium-only fixation at a minimum 2-year follow-up, their modes of failure, and the postoperative complications resulting from the procedure. METHODS: A retrospective review identified 12 consecutive patients treated with custom hemipelvis reconstruction. Indications for surgery were bone tumor requiring internal hemipelvectomy (four patients) or multiply revised, failed hip arthroplasty with massive bone loss (eight patients). All patients had a minimum of 2-year follow-up with a mean of 60.5 months. Kaplan-Meier survivorship analysis was determined for all patients. Postoperative complications and reoperations were categorized for all patients. RESULTS: At a mean of 60.5 months, 11 of 12 patients had retained their custom implant (92% survivorship). One implant was removed as a result of an acute periprosthetic joint infection (PJI). There were no cases of aseptic loosening. Seven of 12 patients required reoperation (three PJI; two dislocations; two superficial wound complications), with five patients going on to reoperation-free survival. CONCLUSIONS: Custom hemipelvis reconstruction utilizing an ilium monoflange provides durable short-term fixation at a minimum 2-year follow-up. Reoperation for infection and dislocation is common.

Virtual planning on contralateral hemipelvis for posteriorly fixed acetabular fractures.

BACKGROUND: Open reduction and internal fixation is a standard treatment for displaced acetabular fractures using 3.5 mm reconstruction plates contoured intra-operatively. This process is difficult and time consuming hence resulting in increased surgical morbidity. Virtual surgical planning is now being commonly used worldwide to aid in management of such complex problems. Patient-specific reconstruction plate pre contoured using virtual surgical planning on contralateral intact hemipelvis will be helpful in achieving better surgical outcomes. Also, it has an added advantage of considerably reducing the time and effort spent in virtual pre-operative planning process. METHODOLOGY: This study was performed in 30 patients with acetabulum fracture who were fixed posteriorly via Kocher-Langenbeck approach. Virtual planning was done on contralateral hemipelvis to prepare patient-specific pre-contoured plates and mirrored to the fractured side. The time required for virtual planning on fractured and normal side was recorded and compared. The efficiency of plates so prepared were accessed in terms of outcome variables like duration of surgery, blood loss, reduction obtained on X-ray as well as CT Scan. RESULT: Time required for virtual planning was more on fractured side and lesser when it was done using normal hemipelvis with mean values of 81.83 (sd = 28.02) min and 15.67 (sd = 6.12) min, respectively. Values of blood loss, duration of surgery and reduction as accessed on X-ray and CT scan were comparable or even better than compared to other studies. CONCLUSION: Contralateral normal pelvis can be used for virtual preoperative planning making the whole process easier and less time consuming.

Three-year follow-up of a Traumatic Hemipelvectomy Survivor: A Case Report.

The management of a patient with traumatic hemipelvectomy is complex. We report the acute management and rehabilitation of a 21-year-old patient as well as her prosthesis modification. She was able to return to society as a K3 level ambulator.

Coned hemipelvis reconstruction for osteoporotic acetabular fractures in frail elderly patients.

AIMS: Complex displaced osteoporotic acetabular fractures in the elderly are associated with high levels of morbidity and mortality. Surgical options include either open reduction and internal fixation alone, or combined with total hip arthroplasty (THA). There remains a cohort of severely comorbid patients who are deemed unfit for extensive surgical reconstruction and are treated conservatively. We describe the results of a coned hemipelvis reconstruction and THA inserted via a posterior approach to the hip as the primary treatment for this severely high-risk cohort. METHODS: We have prospectively monitored a series of 22 cases (21 patients) with a mean follow-up of 32 months (13 to 59). RESULTS: The mean patient age was 79 years (67 to 87), and the mean ASA score was 3.3 (3 to 5). Three patients had high-energy injuries and 18 had low-energy injuries. All cases were associated fractures (Letournel classification: anterior column posterior hemitransverse, n = 13; associated both column, n = 6; transverse posterior wall, n = 3) with medialization of the femoral head. Mean operative time was 93 minutes (61 to 135). There have been no revisions to date. Of the 21 patients, 20 were full weight-bearing on day 1 postoperatively. Mean length of hospital stay was 12 days (5 to 27). Preoperative mobility status was maintained in 13 patients. At one year, mean Merle d'Aubigné score was 13.1 (10 to 18), mean Oxford Hip Score was 38.5 (24 to 44), mean EuroQol five-dimension five-level (EQ-5D-5L) health score was 68 (30 to 92), and mean EQ-5D-5L index score was 0.68 (0.335 to 0.837); data from 14 patients. Mortality was 9.5% (2/21) at one year. There have been no thromboembolic events, deep infections, or revisions. CONCLUSION: The coned hemipelvis reconstruction bypasses the fracture, creating an immediately stable construct that allows immediate full weight-bearing. The posterior approach minimizes the operative time and physiological insult in this vulnerable patient population. Early results suggest this to be a safe addition to current surgical options, targeted at the most medically frail elderly patient with a complex displaced acetabular fracture. Cite this article: Bone Joint J 2020;102-B(2):155-161.

Modeling three-dimensional-printed trabecular metal structures with a homogenization approach: Application to hemipelvis reconstruction.

The application of three-dimensional printing technologies to metal materials allows us to design innovative, low-weight, patient-specific implants for orthopedic prosthesis. This is particularly true when the reconstruction of extensive metastatic bone defect is planned. Modeling complex three-dimensional-printed highly repetitive trabecular-like structures based on finite elements is computationally demanding, while homogenization algorithms offer the advantage of reduced simulation cost and time, allowing an effective evaluation of new personalized design suitable for clinical needs. This article describes and discusses the implementation of a reliable method for the multiscale modeling of trabecular structures by means of asymptotic expansion homogenization. Following the material characterization of the Ti6Al4V alloy obtained by electron beam melting technology, the asymptotic expansion homogenization was applied to two alternative low-density cell-unit designs. Model predictions demonstrated satisfactory agreement with compressive experimental tests and cantilever bending tests performed on both designs (differences lower than 5.5%). The method was extended to a real patient-specific hemipelvis reconstruction, exploiting the capability of the asymptotic expansion homogenization approach in quantitatively describing the effect of cell-unit designs and three-dimensional-printing stack direction (i.e. cell-unit orientation) both on the overall mechanical response of the implant and on the stress distribution. The hemipelvis implant filled with the higher density cell unit demonstrated to be 14% stiffer than using the lower density one, while changing the cell-unit orientation affected the stiffness up to 10%. The maximum stress values reached at the anchors were affected in a minor extent by the investigated design parameters.

Standardization of hemipelvis alignment for in vitro biomechanical testing.

Although in vitro biomechanical tests are regularly performed, the definition of a suitable reference frame for hemipelvic specimens is still a challenge. The aims of the present study were to: (i) define a reference frame for the human hemipelvis suitable for in vitro applications, based on robust anatomical landmarks; (ii) identify the alignment of a hemipelvis based on the alignment of a whole pelvis (including right/left and male/female differences); (iii) identify the relative alignment of the proposed in vitro reference frame with respect to a reference frame commonly used in gait analysis; (iv) create an in vitro alignment procedure easy, robust and inexpensive; (v) quantify the intra-operator repeatability and inter-operator reproducibility of the procedure. A procedure to univocally identify the anatomical landmarks was created, exploiting the in vitro accessibility of the specimen's surface. Through the analysis on 53 CT scans (106 hemipelvises), the alignment of the hemipelvis based on the alignment of a whole pelvis was analyzed: differences between male/female and right/left hemipelvises were not statistically significant To overcome the uncertainty in the identification of the acetabular rim, a standard acetabular plane was defined. An alignment procedure was developed to implement such anatomical reference frame. The intra-operator repeatability and the inter-operator reproducibility were quantified with four operators, on male and female hemipelvises. The intra-operator repeatability was better than 1.5°. The inter-operator reproducibility was better than 2.0°. Alignment in the transverse plane was the most repeatable. The presented procedure to align hemipelvic specimens is sufficiently robust, standardized, and accessible. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1645-1652, 2018.

Total hip replacement in complex acetabular fractures using a coned hemipelvic acetabular component.

Acetabular fractures in the elderly are a challenging clinical problem due to both the complex nature of operative intervention, osteoporotic bone and the multiple comorbidities of the patients involved. They are associated with poor functional outcomes and high levels of morbidity and mortality. Treatment currently ranges from conservative treatment, open reduction internal fixation and variations of total hip arthroplasty. We present the surgical technique and early results of the use of a coned hemipelvic acetabular component in the primary treatment of these complex injuries. Five patients (six cases) with a mean age of 75 years have been followed up for 15 months. There were five minor post-operative complications: two patients suffered mild serous wound ooze, two sustained an acute kidney injury, and one a lower respiratory tract infection. One patient suffered pre-operative bilateral sciatic nerve injury, which has partially resolved. There have been no thromboembolic events, dislocations or infections. There have been no cases of prosthesis migration. Four of five patients were able to mobilise fully weight-bearing day one post-operatively, and at latest follow-up four of five mobilised independently with a walking aid. We feel that early weight-bearing mobilisation is essential to achieve a successful outcome in these patients, in a similar way to neck of femur fracture patients. The coned acetabular prosthesis bypasses the fracture, creating an immediately stable construct which allows mobilisation day one post-operatively. The early results of this new technique are promising. Although follow-up is short, there have been no serious complications, a high level of patient satisfaction and radiological evidence of fracture healing, with no prosthesis migration. We aim to continue utilising this technique, with close monitoring of longer-term results.

Analysis of sacro-iliac joint screw fixation: does quality of reduction and screw orientation influence joint stability? A biomechanical study.

INTRODUCTION: Treatment of posterior pelvic ring injuries is frequently associated with pain or/and high mortality rates. Percutaneous sacro-iliac (SI) screw fixation has proved to be one of the methods of choice, providing minimal operative time, blood loss and wound-related morbidity. However, fixation failures due to secondary fracture dislocation or screw backing out have been reported. There is a little knowledge regarding the impact of varying screw orientation and quality of reduction on the fixation strength. PURPOSE: The purpose of the present study was biomechanical investigation of joint stability after SI screw fixation and its dependence on quality of reduction and screw orientation. METHODS: Thirty-two artificial hemi-pelvices were assigned to four study groups and simulated SI dislocations were fixed with two SI screws in oblique or transverse screw orientation and anatomical or non-anatomical reduction in group A (oblique/anatomical), B (transverse/anatomical), C (oblique/non-anatomical) and D (transverse/non-anatomical). Mechanical testing was performed under progressively increasing cyclic axial loading until fixation failure. SI joint movements were captured via optical motion tracking. Fixation performance was statistically evaluated at a level of significance p = 0.05. RESULTS: The highest cycles to failure were observed in group A (14038 ± 1057), followed by B (13909 ± 1217), D (6936 ± 1654) and C (6706 ± 1295). Groups A and B revealed significantly longer endurance than C and D (p ≤ 0.01). CONCLUSIONS: Different screw orientations in the presented model do not influence substantially SI joint stability. However, anatomical reduction is not only mandatory to restore a malalignment, but also to increase the SI screw fixation strength and prevent fixation failures.