Aims. There are concerns regarding nail/medullary canal mismatch and initial stability after cephalomedullary nailing in unstable pertrochanteric fractures. This study aimed to investigate the effect of an additional anteroposterior blocking screw on fixation stability in unstable pertrochanteric fracture models with a nail/medullary canal mismatch after short cephalomedullary nail (CMN) fixation. Methods. Eight finite element models (FEMs), comprising four different femoral diameters, with and without blocking screws, were constructed, and unstable intertrochanteric fractures fixed with short CMNs were reproduced in all FEMs. Micromotions of distal shaft fragment related to proximal fragment, and stress concentrations at the nail construct were measured. Results. Micromotions in FEMs without a blocking screw significantly increased as nail/medullary canal mismatch increased, but were similar between FEMs with a blocking screw regardless of mismatch. Stress concentration at the nail construct was observed at the junction of the nail body and lag screw in all FEMs, and increased as nail/medullary canal mismatch increased, regardless of blocking screws. Mean stresses over regions of interest in FEMs with a blocking screw were much lower than regions of interest in those without. Mean stresses in FEMs with a blocking screw were lower than the yield strength, yet mean stresses in FEMs without blocking screws having 8 mm and 10 mm mismatch exceeded the yield strength. All mean stresses at distal locking screws were less than the yield strength. Conclusion. Using an additional anteroposterior blocking screw may be a simple and effective method to enhance fixation stability in unstable pertrochanteric fractures with a large nail/medullary canal mismatch due to osteoporosis. Cite this article: Bone Joint Res 2022;11(3):152–161

PURPOSE: The treatment of pertrochanteric fractures is constantly evolving and surgical issues remain controversial. Although the use of a sliding hip screw is considered to be the treatment of choice by many surgeons, we believe that intramedullary nailing could be a viable treatment option for unstable pertrochanteric fractures. Given this background, we compared the clinical outcome of unstable pertrochanteric fractures treated with intramedullary hip screw (IMHS) and standard screws with unstable pertrochanteric fractures treated with intramedullary hip screw using hydroxyapatite (HA)-coated screws. METHODS: Forty consecutive female osteoporotic patients with pertrochanteric fractures were selected. The inclusion criteria were: female; age ≥65 years; pertrochanteric fracture resulting from minor trauma. Patients were randomized by a computer-generated list to receive either IMHS fixed with stainless steel lag screws (Group A) or IMHS fixed with HA-coated pins (Group B). RESULTS: Average patient age was 82 ± 8 years in Group A and 78 ± 6 years in Group B. Average BMD was 512 ± 177 in Group A, and 471 ± 231 in Group B. Average intraoperative time was 64 ± 6 minutes in Group A and 34 ± 5 minutes in Group B (p < 0.005). In Group A, all patients had post-operative blood transfusions averaged 2.0 ± 0.1. In Group B, there were no blood transfusions (p < 0.0001). In Group A, the reduction over time in the femoral neck-shaft angle was 6 ± 8, while in Group B, the reduction was 2 ± 1 (p < 0.002). Conclusion: This study showed that intramedullary hip screw with HA-coated lag screw is an effective treatment for unstable fractures in this patient population. The operative time is brief, the fixation is adequate, and the reduction is maintained over time

Controversy exists whether to treat unstable pertrochanteric hip fractures with either intra-medullary or extra-medullary devices. A prospective randomised control trial was performed to compare the outcome of unstable pertrochanteric hip fractures stabilised with either a sliding hip screw or long Gamma Nail. The hypothesis was that there is no difference in outcome between the two modes of treatment. Over a four year period, 210 patients presenting with an unstable pertrochanteric hip fracture (AO/OTA 31 A2) were recruited into the study. Eligible patients were randomised on admission to either long Gamma Nail or sliding hip screw. Follow-up was arranged for three, six, and twelve months. Primary outcome measures were implant failure or ‘cut-out’. Secondary measures included mortality, length of hospital stay, transfusion rate, change in mobility and residence, and EuroQol outcome score. Five patients required revision surgery for implant cut-out (2.5%), of which three were long Gamma Nails and two were sliding hip screws (no significant difference). There were no incidences of implant failure or deep infection. Tip apex distance was found to correlate with implant cut-out. There was no statistically significant difference in either the EuroQol outcome scores or mortality rates between the two groups when corrected for mini mental score. There was no difference in transfusion rates, length of hospital stay, and change in mobility or residence. There was a clear cost difference between the implants. The sliding hip screw remains the gold standard in the treatment of unstable pertrochanteric fractures of the proximal femur

Controversy exists whether to treat unstable pertrochanteric hip fractures with either intramedullary or extramedullary devices. A prospective randomised control trial was performed to compare the outcome of unstable pertrochanteric hip fractures stabilised with either a sliding hip screw (SHS) or Long Gamma Nail (LGN). The hypothesis was that there is no difference in outcome between the two modes of treatment. Over a four year period, 210 patients presenting with an unstable pertrochanteric hip fracture (AO/OTA 31 A2.1/A2.2/A2.3) were recruited into the study. Eligible patients were randomised on admission to either LGN or SHS. Follow-up was arranged for three, six, and twelve months. Primary outcome measures were implant failure and implant ‘cut-out’. Secondary measures included mortality, length of hospital stay, and EuroQol outcome score. Five patients required revision surgery for implant cutout, of which three were LGNs and two were SHSs (no significant difference). There was a significant correlation between tip apex distance and the need for revision surgery. There were no incidences of implant failure or deep infection. Mortality rates between the two groups were similar when corrected for mini mental score. There was no difference between the two groups with respect to tip apex distance, hospital length of stay, blood transfusion requirement, and EuroQol outcome score. The sliding hip screw remains the gold standard in the treatment of unstable pertrochanteric fractures of the proximal femur

Background. A large proportion of the expense incurred due to hip fractures arises due to secondary factors such as duration of hospital stay and additional theatre time due to surgical complications. Studies have shown that the use of intramedullary (IM) nail fixation presents a statistically higher risk of re-fracture than plating, which has been attributed to the stress riser at the end of the nail. It is not clear, however, if this situation also applies to unstable fractures, for which plating has a higher fixation failure rate. Moreover, biomechanical studies to date have not considered newer designs of IM nails which have been specifically designed to better distribute weight-bearing loads. This aim of this experimental study was to evaluate the re-fracture risk produced by a newer type of nailing system compared to an equivalent plate. Methods. Experimental testing was conducted using fourth generation Sawbones composite femurs and X-Bolt IM hip nail (n=4) and fracture plate (n=4) implants. An unstable pertrochanteric fracture pattern was used (AO classification: 31-A1 / 31-A2). Loading was applied along the peak loading vector experienced during walking, up to a maximum load of 500N. The risk of re-fracture was evaluated from equivalent strains measured using four rosette strain gauges on the surface of the bone at known stress riser locations. Results. Strain gauge readings determined that the equivalent strains in the femoral diaphysis were approximately 25% larger for the nail than the plate (p < 0.005). The strain levels at the location coinciding with the end of the plate were also larger for the nail, but not significantly (p > 0.26). Conclusions. Although the risk of re-fracture for displaced tronchantaric fractures was found to be larger for nailing than plating, measured strains were substantially lower than the failure strain of cortical bone (even when scaled for full weight-bearing loads of 1800N). This indicates that fracture risk is not present in either implant for bone of healthy quality, but may still become problematic in highly osteoporotic patients. Level of Evidence. IIb - Evidence from at least one well designed experimental trial

Hip fractures constitute the most debilitating complication of osteoporosis with a steadily increasing incidence in an aging population. Intramedullary nailing of osteoporotic proximal femoral fractures can be challenging because of poor implant anchorage in the femoral head. Recently, cement augmentation of PFNA blades with Polymethylmethycrylate (PMMA) has shown promising results by enhancing the cutout resistance in proximal femoral fractures. The aim of this biomechanical study was to assess the impact of cement augmentation on the fixation strength of TFNA blades and screws within the femoral head, and compare its effect with head elements placed in a center or antero–posterior off–center positions. Eight groups were formed out of 96 polyurethane foam specimens with low density, simulating isolated femoral heads with severe osteoporotic bone. The specimens in each group were implanted with either non–augmented or PMMA–augmented TFNA blades or screws in a center or antero–posterior off–center position, 7 mm anterior or 7 mm posterior. They were mechanically tested in a setup simulating an unstable pertrochanteric fracture with lack of postero–medial support and load sharing at the fracture gap. All specimens underwent progressively increasing cyclic loading until catastrophic construct failure. Varus–valgus and head rotation angles were monitored by an inclinometer mounted on the head. A varus collapse of 5° or a 10° head rotation were defined as the clinically relevant failure criterion. Load at failure for specimens with augmented TFNA head elements (screw center: 3799 N ± 326 (mean ± SD); blade center: 3228 N ± 478; screw off–center: 2680 N ± 182; blade off–center: 2591 N ± 244) was significantly higher compared to the respective non–augmented specimens (blade center: 1489 N ± 41; screw center: 1593 N ± 120; blade off–center: 1018 N ± 48; screw off–center: 515 N ± 73), p<0.001. In both non–augmented and augmented specimens, the failure load in center position was significantly higher compared to the respective off–center position, regardless of head element, p<0.001. Non–augmented TFNA blades in off–center position revealed significantly higher load at failure versus non–augmented screws in off–center position, p<0.001. Cement augmentation clearly enhances fixation stability of TFNA blades and screws. Non–augmented blades outperformed screws in antero–posterior off–center position. Positioning of TFNA blades in the femoral head is more forgiving than TFNA screws in terms of failure load. Augmentation with TFNA has not been approved by FDA

Summary. Biomechanically, a 2° screw deviation from the nominal axis in the PFLCP leads to significantly earlier implant failure. Screw deviation relies on a technical error on insertion, but in our opinion cannot be controlled intraoperatively with the existing instrumentation devices. Background. Several cases of clinical failure have been reported for the Proximal Femoral Locking Compression Plate (PFLCP). The current study was designed to investigate the failure mode and to explore biomechanically the underlying mechanism. Specifically, the study sought to determine if the observed failure was due to technical error on insertion or due to implant design. Methods. To exclude patient and fracture type related factors, an abstract foam block model simulating an unstable pertrochanteric fracture was created for three study groups with six specimens each (n=6). Group 1 was properly instrumented according to the manufacturer's guidelines. In Group 2 and 3, the first or second screw was placed in a posterior or anterior off-axis orientation by 2° measured in the transversal plane, respectively. Each construct was tested cyclically until failure using a test setup and protocol simulating complex axial and torsional loading. Radiographs were taken prior to and after the tests. Force, number of cycles and failure mode were compared. Results. The 2° screw deviation from the nominal axis led to significantly earlier construct failure in Group 2 and 3. The failure mode consisted of loosening of the off-axis screw due to disengagement with the plate, resulting in loss of construct stiffness and varus collapse of the fracture. Conclusions. In our biomechanical test setup, a screw deviation of only 2° from the nominal axis consistently led to the failure mode observed clinically. In our opinion, screw deviation mostly relies on technical error on insertion. But, proper screw insertion may be difficult or impossible with the existing instrumentation devices, especially as it cannot be controlled or guaranteed intraoperatively

Introduction. Internal fixation of pertrochanteric fractures is evolving as newer implants are being developed. Proximal Femoral Nail Antirotation (PFNA) is a recently introduced implant from AO/ASIF designed to compact the cancellous bone and may be particularly useful in unstable and osteoporotic hip fractures. This study is a single and independent centre experience of this implant used in management of acute hip fractures. Methods. 68 patients involving 68 PFNA nailing procedures done over a period of 2 years (2007–09) were included in the study. Average follow-up period of patients was 1 year. AO classification for trochanteric fractures was used to classify all the fractures. Radiological parameters including tip-apex distance and neck shaft angle measurement were assessed. Results. Average age of patients included in the study was 80 years. 18 patients died during the follow up period due to non-procedure related causes. Average tip-apex distance was 12.7 mm and radiological fracture union time was 5 months. Revision of short to a long PFNA was needed for periprosthetic fracture of shaft of femur in two patients. Two patients needed a complex total hip replacement eventually and further two patients had removal of the implant due to PFNA blade penetration through the femoral head. Discussion. PFNA is a technically demanding procedure and has a learning curve. Our experience shows that it is a useful implant in unstable pertrochanteric fracture fixation. A close radiological and clinical follow up is recommended due to the risk of late fracture and implant related complications

Objectives

The paradoxical migration of the femoral neck element (FNE) superomedially against gravity, with respect to the intramedullary component of the cephalomedullary device, is a poorly understood phenomenon increasingly seen in the management of pertrochanteric hip fractures with the intramedullary nail. The aim of this study was to investigate the role of bidirectional loading on the medial migration phenomenon, based on unique wear patterns seen on scanning electron microscopy of retrieved implants suggestive of FNE toggling.

Objectives

The Sliding Hip Screw (SHS) is commonly used to treat trochanteric hip fractures. Fixation failure is a devastating complication requiring complex revision surgery. One mode of fixation failure is lag screw cut-out which is greatest in unstable fracture patterns and when the tip-apex distance of the lag screw is > 25 mm. The X-Bolt Dynamic Hip Plating System (X-Bolt Orthopaedics, Dublin, Ireland) is a new device which aims to reduce this risk of cut-out. However, some surgeons have reported difficulty minimising the tip-apex distance with subsequent concerns that this may lead to an increased risk of cut-out.

Despite advances in the prevention and treatment of osteoporotic fractures, their prevalence continues to increase. Their operative treatment remains a challenge for the surgeon, often with unpredictable outcomes. This review highlights the current aspects of management of these fractures and focuses on advances in implant design and surgical technique.