Forces required to dynamize sliding screws in gamma nail and selfdynamizable internal fixator.

BACKGROUND: Single limb support phase of the gait-cycle in patients who are treated for a pertrochanteric fracture is characterized by transversal loads acting on the lag screw, tending to block its dynamization. If the simultaneous axial force overcomes transversal loads of the sliding screw, the dynamization can still occur. METHODS: Biomechanical investigation was performed for three types of dynamic implants: Gamma Nail, and two types of Selfdynamizable Internal Fixators (SIF) - SIF-7 (containing two 7 mm non-cannulated sliding screws), and SIF-10 (containing one 10 mm cannulated sliding screw). Contact surface between the stem and the sliding screws is larger in SIF implants than in Gamma Nail, as the stem of Gamma Nail is hollow. A special testing device was designed for this study to provide simultaneous application of a controlled sliding screws bending moment and a controlled transversal load on sliding screws (Qt) without using of weights. Using each of the implants, axial forces required to initiate sliding screws dynamization (Qa) were applied and measured using a tensile testing machine, for several values of sliding screws bending moment. Standard least-squares method was used to present the results through the linear regression model. RESULTS: Positive correlation between Qt and Qa was confirmed (p < 0.05). While performing higher bending moments in all the tested implants, Qa was higher than it could be provided by the body weight. It was the highest in Gamma Nail, and the lowest in SIF-10. CONCLUSIONS: A larger contact surface between a sliding screw and stem results in lower forces required to initiate dynamization of a sliding screw. Patients treated for a pertrochanteric fracture by a sliding screw internal fixation who have longer femoral neck or higher body weight could have different programme of early postoperative rehabilitation than lighter patients or patients with shorter femoral neck.

Retrospective evaluation of radiological and clinical outcomes after surgical treatment of proximal femoral fractures utilizing PFNA and PFNA augmented.

INTRODUCTION: The primary aim of this study was to evaluate the clinical and radiological outcomes after surgical treatment of proximal femoral fractures utilizing the Proximal Femoral Nail Antirotation (PFNA), with the main focus on complications and reoperations. The secondary aim was to compare the outcomes of patients with and without cement augmentation of the cephalomedullary nails. MATERIALS AND METHODS: All patients with an acute proximal femoral fracture consequently treated with a PFNA between January 2011 and Dezember  2018 were evaluated. Clinical and radiological data were assessed for intra- and postoperative complications, including treatment failure. In addition, intra- and postoperative radiographs were used to determine the position of the implant, and any migration, via Tip-Apex-Distance (TAD) and the caput-collum-diaphyseal angle (CCD). The accuracy of the fracture reduction was rated according to Baumgaertners criteria. RESULTS: Two hundred sixty-four consecutive patients (mean age 78.8 ± 12.0; 73.1% female) were included. The predominant OTA/AO fracture classification was 31A1 (153 cases, 58.0%). The average duration of surgery was 63.1 ± 28.0 min and showed no significant differences between PFNA and PFNA with augmentation. The implant positioning was rated as good in 222 cases (84.1%). Two hundred sixty-three patients (99.6%) showed evidence of healing within the time frame of three months postoperatively, one case of delayed union healed after secondary dynamization. During the observational period, 18 patients (6.8%) required a total of 23 additional surgeries. Overall, a lower reoperation rate was observed following the use of the augmentation option (2/86 patients (2.3%) vs. 16/178 patients (9.0%), p = 0.04). In particular, there were no cases of cut-out or cut-through among patients who underwent augmentation as part of osteosynthesis. CONCLUSIONS: Overall reoperation rate after surgical treatment of proximal femoral fractures utilizing the Proximal Femoral Nail Antirotation (PFNA) was 6.8%, with 23 additional surgeries performed in 18 patients. The usage of the PFNA with augmentation showed equally good implant positioning, excellent healing rates and fewer postoperative complications compared to the PFNA implant alone with a similar overall duration of surgery.

Impact of lateral cortical notching on biomechanical performance in cephalomedullary nailing for unstable pertrochanteric fractures.

PURPOSE: In pertrochanteric femur fractures the risk for fracture healing complications increases with the complexity of the fracture. In addition to dynamization along the lag screw, successful fracture healing may also be facilitated by further dynamization along the shaft axis. The aim of this study was to investigate the mechanical stability of additional axial notch dynamization compared to the standard treatment in an unstable pertrochanteric femur fracture treated with cephalomedullary nailing. METHODS: In 14 human cadaver femora, an unstable pertrochanteric fracture was stabilized with a cephalomedullary nail. Additional axial notch dynamization was enabled in half of the samples and compared against the standard treatment (n = 7). Interfragmentary motion, axial construct stiffness and load to failure were investigated in a stepwise increasing cyclic load protocol. RESULTS: Mean load to failure (1414 ± 234 N vs. 1428 ± 149 N, p = 0.89) and mean cycles to failure (197,129 ± 45,087 vs. 191,708 ± 30,490, p = 0.81) were equivalent for axial notch dynamization and standard treatment, respectively. Initial construct stiffness was comparable for both groups (axial notch dynamization 684 [593-775] N/mm, standard treatment 618 [497-740] N/mm, p = 0.44). In six out of seven specimens the additional axial dynamization facilitated interfragmentary compression, while maintaining its mechanical stability. After initial settling of the constructs, there were no statistically significant differences between the groups for either subsidence or rotation of the femoral head fragment (p ≤ 0.30). CONCLUSION: Axial notch dynamization provided equivalent mechanical stability compared to standard treatment in an unstable pertrochanteric fracture. Whether the interfragmentary compression generated by axial notch dynamization will promote fracture healing through improved fracture reduction needs to be evaluated clinically.

Factors Associated With Failure of Synthesis in the Treatment of Proximal Femur Fractures With Cephalomedullary Nails.

INTRODUCTION: Proximal femur fractures are common in older patients and typically require surgical treatment, with cephalomedullary nails being the gold standard device for this approach. This study aimed to identify the factors associated with the failure of cephalomedullary nailing. MATERIALS AND METHODS: We retrospectively evaluated 380 patients treated with a cephalomedullary nail between August 2021 and August 2022 in a trauma referral center in Brazil. A total of 221 (58.1%) patients were included in the study after applying specific eligibility criteria. Data were collected and rates were determined by reviewing patients' medical records and radiographs. RESULTS: Of 221 patients, 14 (6.3%) had nail failures A significant association was found between post-fixation cervico-diaphyseal angle and the occurrence of nail failure (p<0.001). Furthermore, calcar-referenced tip-apex distance (CalTAD) and tip-apex distance (TAD) values were higher in cases with nail failure than in those without nail failure. Cutoff points were established for TAD and CalTAD to measure the correspondence with nail failures. CONCLUSION: The present study supports previous evidence that varus reduction potentially causes collapse and nail failure in pertrochanteric fractures treated with cephalomedullary nailing and that high TAD and CalTAD values contribute to the incidence of cut-out.

Incidence and Risk Factors of Osteonecrosis of the Femoral Head after Cephalomedullary Nailing for Pertrochanteric Fractures: Observational Single-Center Study.

Background: The objective of this study was to investigate the incidence of osteonecrosis of the femoral head (ONFH) after cephalomedullary nailing in elderly patients with pertrochanteric fractures and to analyze the risk factors related to ONFH. Methods: A total of 689 consecutive patients with cephalomedullary nailing for pertrochanteric fractures at our hospital were recruited. Of these, 368 patients who met the inclusion criteria were finally enrolled. ONFH after cephalomedullary nailing was identified by reviewing patients' electronic charts and serial radiographs. The ONFH group was then compared with the non-ONFH group. Results: ONFH was identified in 9 of 368 patients (2.4%). The time to diagnosis of ONFH averaged 23.8 months (range, 5-54 months) after index surgery. The mean age, body mass index, and bone mineral density (T-score in femur neck) were 84.1 ± 7.1 years, 23.7 ± 3.6 kg/m2, and -3.1 ± 0.7 kg/m2, respectively. The times from injury to surgery, from admission to surgery, and operation time averaged 4.2 ± 2.7 days, 3.6 ± 2.6 days, and 87.2 ± 30.0 minutes, respectively. Among 9 patients, 3 underwent conversion arthroplasty. The ONFH group had advanced age (p = 0.029), more basicervical fracture components (p = 0.002), and inadequate reduction (p = 0.045) compared to the non-ONFH group. On multivariate analysis, advanced age (odds ratio [OR], 1.61;, p = 0.022), basicervical fracture components (OR, 24.58; p = 0.001), and inadequate reduction (OR, 4.11; p = 0.039) were identified as risk factors of ONFH. Conclusions: Although ONFH is relatively rare after cephalomedullary nailing for pertrochanteric fractures in elderly patients, its risk may increase with advanced age, basicervical fracture components, and inadequate reduction. Therefore, in patients with these risk factors, meticulous and longer follow-up is needed even after bone union.

Risk Factors for Therapeutic Failure and One-Year Mortality in Patients with Intramedullary Nail-Associated Infection after Trochanteric and Subtrochanteric Hip Fracture Repair.

Despite the implications of trochanteric and subtrochanteric intramedullary (IM) nail infection for patients with hip fracture, little is known about risk factors for therapeutic failure and mortality in this population. We performed a retrospective observational analysis including patients diagnosed with trochanteric and subtrochanteric IM nail infection at a Spanish academic hospital during a 10-year period, with a minimum follow-up of 22 months. Of 4044 trochanteric and subtrochanteric IM nail implants, we identified 35 cases of infection during the study period (0.87%), 17 of which were chronic infections. Patients with therapeutic failure (n = 10) presented a higher average Charlson Comorbidity Index (CCI) (5.40 vs. 4.21, p 0.015, CI 0.26-2.13) and higher rates of polymicrobial (OR 5.70, p 0.033, CI 1.14-28.33) and multidrug-resistant (OR 7.00, p 0.027, CI 1.24-39.57) infections. Upon multivariate analysis, polymicrobial infection and the presence of multidrug-resistant pathogens were identified as independent risk factors for therapeutic failure. Implant retention was associated with an increased risk of failure in chronic infection and was found to be an independent risk factor for overall one-year mortality in the multivariate analysis. Our study highlights the importance of broad-spectrum empirical antibiotics as initial treatment of trochanteric and subtrochanteric IM nail-associated infection while awaiting microbiological results. It also provides initial evidence for the importance of implant removal in chronic IM-nail infection.

Role of Anteromedial Cortical Support for Unstable Intertrochanteric Fractures Being Treated With Cephalomedullary Nails.

INTRODUCTION: Reduction quality is of paramount importance for an optimal outcome in unstable pertrochanteric fractures. The non-anatomical functional anteromedial buttress is proposed to prevent impending mechanical complications. We aimed to evaluate the role of anteromedial cortical support in preventing mechanical complications following fixation with the cephalomedullary nail. MATERIALS AND METHODS: A prospective, single-arm interventional study was conducted in the Orthopaedics Department of a Combined Military Hospital (CMH) in Rawalpindi. The duration of the study was 24 months. Patients were recruited by the purposive sampling technique as per inclusion/exclusion criteria. Preoperatively, the reduction was categorized as per Baumgartner's and Chang's criteria. Post-operatively, weight bearing as tolerated was advised. Radiographs prior to discharge for loss of reduction were evaluated. Follow-up radiographic measurements of neck length, neck shaft angle, and their loss as per protocol were done at three and six months. RESULTS: A total of 202 patients were operated on from October 21 until August 23. Mortality at six months in 39 patients (19.3%) and loss to follow-up in 31 patients (15.3%) resulted in 132 patients with complete follow-up and having developed complications in 12 patients (9.09%). The mean age was 76.3 ± 7.98 years; males were 105 (79.5%), and females were 27 (20.5%). Closed reduction was 58 (43.9%), and additional manoeuvres were required in 74 (56.1%). The mean tip apex distance (TAD) was 24.56 ± 2.76, and the Calcar gap was 5.16 ± 1.27. Cleveland zone centre-centre in 54 (40.9%), inferior-centre in 65 (49.2%), and inferior-posterior (9.9%) were statistically significant for mechanical complications (p≤0.001). There was a significant association between the grading of Chang's and Baumgartner's poor groups for the development of mechanical complications (p≤0.001). The mean time to full weight bearing without support was 21 ± 1.22 weeks. The mean Hip Harris score at six months was 69.27 ± 7.68. CONCLUSION: Results suggest that anteromedial cortical support can lead to fewer potential mechanical complications at six months. A higher Chang's grade drives surgeons to engage in additional manoeuvres. Anteromedial cortical support is worth consideration for unstable pertrochanteric fractures.

Challenges of Hip Arthroplasty in a Paretic, Spastic Limb: A Case Study on Managing Femoral Neck Fracture Following Fixation Failure in a Hemiparetic Patient.

Background: Hip fractures and strokes are prevalent and escalating issues in geriatric healthcare. The absence of standardized surgical protocols for patients with spastic hemiparesis and multiple comorbidities presents a significant medical challenge. Methods: This case study describes a 64-year-old male patient with left-sided hemiparesis and failed surgical treatment of a pertrochanteric fracture in a spastic limb. The patient was admitted to the Department of Rehabilitation and Orthopedics in December 2022 for diagnostics and to establish a treatment plan after five months of non-ambulatory status. Results: This study emphasizes the crucial role of preoperative preparation, involving botulinum toxin injections into spastic muscles and physiotherapy, to enhance the supportive function of the paretic limb and improve locomotion before prosthetic surgery. Conclusions: The management of hip fractures in patients with spastic paralysis requires a multidisciplinary approach and the development of standardized treatment protocols. This case underscores the importance of comprehensive pre- and postoperative rehabilitation to improve patient outcomes. Further research is needed to establish standardized rehabilitation protocols for spastic patients undergoing hip arthroplasty. Randomized controlled trials could provide valuable insights into the efficacy of various interventions.

Nailing intertrochanteric fractures in geriatric population: Do we know it all?

INTRODUCTION AND OBJECTIVES: Pertrochanteric fractures constitute an important part of the daily activity of the orthopedic surgeon. The aim of this study was to carry out an analysis of pre-, intra- and post-operative radiographic parameters and to analyze the results of stable and unstable intertrochanteric fractures treated with short nails with dynamic distal locking. MATERIALS AND METHODS: Retrospective study in our center, between the years 2017-2021 of patients over 65 years of age with pertrochanteric fracture. We included 272 patients treated with Gamma3 Nail (Stryker®) with dynamic distal locking. As variables, we recorded: age, medical comorbidities, fracture pattern according to AO/OTA, osteopenia according to Singh's classification, pre-operative (such as diaphyseal extension), intra-operative (such as tip-to-the-apex or medial cortical support) and post-operative radiographic parameters (such as time to consolidation or loss of reduction), pre- and post-operative Barthel, quality of life and complications and reinterventions, such as non-union or cut-out. RESULTS: The mean age was 83.28 years (65-102). Two hundred four cases were women (75%). The average follow-up was 18.2 months (12-24). The distribution according to AO/OTA classification was 85.7% 31.A1; 12.5% 31.A2; 1.9% 31.A3. Radiographic consolidation was obtained in 97.4% of cases. Tip to apex distance was less than 25mm in 95.6% of cases. Medial cortical support was positive or neutral in 88.6% of cases. Sixty cases (22.1%) of screw back-out were recorded. Eight reinterventions (2.9%) were performed, corresponding to three cut-outs (1.1%), three non-unions (1.1%), one avascular necrosis (0.4%) and one secondary hip osteoarthritis (0.4%). CONCLUSIONS: Short nail with dynamic distal locking offers good clinical, radiological and functional results in all types of AO/OTA patterns, without increasing the complication rate, as long as there is an appropriate tip-to-the-apex distance and good medial cortical support.