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.

Pertrochanteric hip fracture is associated with mobility decline and poorer physical performance 4 to 6 months post-hip fracture.

BACKGROUND: To study the effect of hip fracture type on physical performance, functional ability and change in mobility four to six months after the injury. METHODS: A total of 1331 patients out of consecutive 2052 patients aged ≥ 65 years who underwent hip fracture surgery were included in the study. Patient information was collected on admission, during hospitalization, by phone interview and at the geriatric outpatient clinic 4 to 6 months after the fracture. Of the 1331 eligible patients, Grip strength, Timed Up and Go -test (TUG), Elderly Mobility Scale (EMS), mobility change compared to pre-fracture mobility level, Basic Activities of Daily Living (BADL) and Instrumental Activities of Daily Living (IADL) were used to determine physical performance and functional ability. Logistic regression was used for the analyses which was adjusted for gender, age, American Society of Anesthesiologists score, diagnosis of cognitive disorder, pre-fracture living arrangements, mobility and need of mobility aid. RESULTS: Patients with pertrochanteric hip fracture had an EMS lower than 14 (Odds Ratio (OR) 1.38, 95% confidence intervals (CI) 1.00-1.90), TUG time ≥ 20 s (OR 1.69, 95% CI 1.22-2.33) and they had declined in mobility (OR 1.58, 95% CI 1.20-2.09) compared to femoral neck fracture patients 4 to 6 months post-hip fracture in multivariable-adjusted logistic regression analyses. Grip strength and functional ability (IADL, BADL) 4 to 6 months after hip fracture did not differ between fracture types. There were no statistically significant differences in physical performance in patients with a subtrochanteric fracture compared to patients with a femoral neck fracture. CONCLUSIONS: Pertrochanteric hip fracture independently associated with poorer physical performance 4 to 6 months post hip fracture compared to other hip fracture types. Pertrochanteric hip fracture patients should be given special attention in terms of regaining their previous level of mobility.

The remnant axial cortical length of the proximal femur in pertrochanteric fractures: a three-dimensional computed tomography study and its clinical implications.

BACKGROUND: Cortical buttress are important factors for postoperative stable reconstruction of per/inter-trochanteric fractures. The study aimed to measure the remnant axial cortical length (RACL) of the proximal circumference of the femur, and to determine which part of the RACL can be used reliably to postoperatively sustain the head-neck fragment as a cortical support pattern. METHODS: Eighty patients with trochanteric hip fractures admitted from January 2015 to January 2016 were included in a retrospective study. Their pre-operative computed tomography (CT) images were used to form 3D-CT reconstructions via Mimics software. After simulated rotation and movement for fracture reduction, the RACL, its three component parts-namely, the remnant anterior cortex (RAC), remnant lateral cortex (RLC), and remnant posterior cortex (RPC) -the γ angle between the anterior and posterior cortex, and the Hsu's lateral wall thickness (LWT) were evaluated. RESULTS: Patients with an A1 fracture (21/80) had a longer RACL (88.8 ± 15.8 mm) than those with an A2 fracture (60.0 ± 11.9 mm; P < 0.01). The RAC, RLC, and RPC of the RACL in A1 fractures were also significantly longer than those in A2 fractures (P < 0.001). However, the most significant difference among the three components of the RACL was in the RPC, which was 27.3 ± 7.8 mm in A1 fractures and 9.2 ± 6.6 mm in A2 fractures. In addition, the coefficient of variation of the RAC was only 20.0%, while that of the RPC was 75.5%. The average γ angle in A1 fractures was 16.2 ± 13.1°, which was significantly smaller than that in A2 fractures, which was 40.3 ± 14.5° (P < 0.001). There was a significant statistical difference in the LWT between A1 and A2 fractures (P < 0.001). There were significant differences in the RACL, RAC, RLC, RPC, γ angle, and LWT among the five subtypes (P < 0.001). CONCLUSIONS: The RAC is relatively stable in pertrochanteric fractures. Fracture reduction through a RAC buttress may help to enhance the postoperative stable reconstruction of per/inter-trochanteric fractures and make possible good mechanical support for fracture healing.

Charlson comorbidity index predicts the 10-year survivorship of the operatively treated hip fracture patients.

PURPOSE: The aim of this study was to determine how Charlson comorbidity index (CCI) predicts the 10-year survival of operatively treated hip fracture patients aged ≥ 65 years. METHODS: This retrospective cohort study included all consecutive patients who had a hip fracture and were operatively treated upon in the study period from 01 January 2007 to 31 December 2007 at the university hospital. The clinical patient data were obtained from the medical records, and CCI score was calculated. The CCI predicts the 10-year mortality for a patient who may have a range of 22 comorbid conditions. Cumulative survival and complications were evaluated in terms of gender. RESULTS: A total of 241 hip fractures were studied; of these, 183/241 (76%) were females. A total of 32/241 (15%) complications were found, of which 26/241 (11%) were considered major. Overall, 213/241 (88%) patients died during the 10 years of follow-up. Cumulative survival estimates for females were 13% at 10 years (SE = 0.3, 95% CI 3.8-4.8), and for males, it was 12% at 10 years (SE = 0.5, 95% CI 2.8-4.6) (p = 0.33). CCI was significantly associated with mortality after the hip fracture as patients with CCI scores ≥ 4 were at a 3.1-8.5 times higher risk of death compared to patients with low CCI scores of 2-3 (p < 0.001). CONCLUSION: Complications are common after operatively treated hip fracture. Advanced age, living in a care facility, ASA class 4 and high CCI score ≥ 4 were risk factors of mortality after the operatively treated hip fracture.

Complication rates after proximal femoral nailing: does level of training matter?

BACKGROUND: Surgical treatment of pertrochanteric fractures is one of the most performed surgeries in orthogeriatrics. Proximal femoral nailing, the most performed procedure, is often used as a training surgery for young residents. The objective of this study was to evaluate the relevance of the resident's training level to complication rates. MATERIAL AND METHODS: This study was a retrospective cohort study. Surgeons were divided into four groups according to their training level. Complications included infection, cut-out, and revision surgery. The study was performed at a level 1 trauma center. All patients who were treated with proximal femoral nailing surgery with a radiological follow-up of at least 3 months were included. RESULTS: Of the 955 patients extracted, a total of 564 patients met the inclusion criteria. Second-year residents had significantly higher cut-out rates (p = 0.012). Further analysis indicated a correlation between level of training and surgery duration (p < 0.001) as well as a correlation between surgery duration and infection rate (p < 0.001). The overall complication rate was 11.2%. Analyzing overall complications, no significant difference was found when comparing surgeon groups (p = 0.3). No statistically significant difference was found concerning infection (p = 0.6), cut-out (p = 0.7), and revision surgery (p = 0.3) either. CONCLUSION: Complication rates after proximal femoral nailing are not higher in patients who are treated by residents. Therefore, proximal femoral nailing is an excellent procedure for general orthopedic training. However, we must keep in mind that accurate positioning of the femoral neck screw is essential to keep cut-out rates as low as possible.

Calcar fracture gapping: a reliable predictor of anteromedial cortical support failure after cephalomedullary nailing for pertrochanteric femur fractures.

BACKGROUND: Maintaining anteromedial cortical support is essential for controlling sliding and decreasing postoperative implant-related complications. However, adequate fracture reduction with cortical support in immediate postoperative fluoroscopy is not invariable in postoperative follow-ups. This study was conducted to investigate the risk factors leading to anteromedial cortical support failure in follow up for pertrochanteric femur fractures treated with cephalomedullary nails. METHODS: This retrospective study enrolled 159 patients with pertrochanteric fractures (AO/OTA- 31A1 and 31A2) that fixed with cephalomedullary nails. All patients were evaluated as adequate fracture reduction in immediate postoperative fluoroscopy before leaving the operation theater. The patients were separated into two groups based on the condition of the anteromedial cortex in the postoperative 3D CT with full-range observation: those with calcar support maintained in Group 1 and those with calcar support lost in Group 2. Demographic information, fracture classification, TAD (tip-apex distance), Cal-TAD, Parker ratio, NSA (neck-shaft angle), reduction quality score, and calcar fracture gapping were collected and compared. Logistic regression analysis was conducted to explore the risk factors leading to anteromedial cortex change. RESULTS: Anteromedial cortical support failure was noted in 46 cases (29%). There was no significant difference between the two groups concerning age, sex, side injury, TAD, Cal-TAD, Parker ratio, or NSA. There was a significant difference in the AO/OTA fracture classification in univariate analysis but no difference in the multivariable analysis. The reduction quality score, calcar fracture gapping in the AP (anteroposterior), and lateral views were significantly associated with anteromedial cortical support failure in follow-up after cephalomedullary nailing in the multivariable analysis. The threshold value of calcar fracture gapping for the risk of loss was 4.2 mm in the AP and 3.8 mm in the lateral fluoroscopies. Mechanical complications (lateral sliding and varus) were frequently observed in the negative anteromedial cortical support group. CONCLUSIONS: Good reduction quality was a protective factor, and larger calcar fracture gapping in the AP and lateral views were risk factors leading to the postoperative loss of anteromedial cortical support. Therefore, we should pay close attention to fracture reduction and minimize the calcar fracture gap during surgery.

The effect of postoperative weight-bearing status on mortality rate following proximal femoral fractures surgery.

INTRODUCTION: Proximal femur fractures are associated with an increased mortality rate in the elderly. Early weight-bearing presents as a modifiable factor that may reduce negative postoperative outcomes and complications. As such, we aimed to compare non-weight-bearing, partial-weight-bearing and full weight-bearing cohorts, in terms of risk factors and postoperative outcomes and complications. METHODS: We retrospectively reviewed our database to identify the three cohorts based on the postoperative weight-bearing status the day of surgery from 2003 to 20014. We collected data on numerous risk factors, including age, cerebrovascular accident (CVA), pulmonary embolism (PE), surgical fixation method and diagnosis type. We also collected data on postoperative outcomes, including the number of days of hospitalization, pain levels, and mortality rate. We performed a univariate and multivariate analysis; P < 0.05 was the significant threshold. RESULTS: There were 186 patients in the non-weight-bearing group, 127 patients in the partial-weight-bearing group and 1791 patients in the full weight-bearing group. We found a significant difference in the type of diagnosis between cohorts (P < 0.001 in univariate, P < 0.001 in multivariate), but not in fixation type (P < 0.001 in univariate, but P = 0.76 in multivariate). The full weight-bearing group was diagnosed most with pertrochanteric fracture, 48.0%, and used Richard's nailing predominantly. Finally, we found that age was not a significant determinant of mortality rate but only weight-bearing cohort (P = 0.13 vs. P < 0.001, respectively). CONCLUSION: We recommend early weight-bearing, which may act to decrease the mortality rate compared to non-weight-bearing and partial weight-bearing. In addition, appropriate expectations and standardizations should be set since age and type of diagnosis act as significant predictors of weight-bearing status.

Standardized artificially created stable pertrochanteric femur fractures present more homogenous results compared to osteotomies for orthopaedic implant testing.

BACKGROUND: With regard to biomechanical testing of orthopaedic implants, there is no consensus on whether artificial creation of standardized bone fractures or their simulation by means of osteotomies result in more realistic outcomes. Therefore, the aim of this study was to artificially create and analyze in an appropriate setting the biomechanical behavior of standardized stable pertrochanteric fractures versus their simulation via osteotomizing. METHODS: Eight pairs of fresh-frozen human cadaveric femora aged 72.7 ± 14.9 years (range 48-89 years) were assigned in paired fashion to two study groups. In Group 1, stable pertrochanteric fractures AO/OTA 31-A1 were artificially created via constant force application on the anterior cortex of the femur through a blunt guillotine blade. The same fracture type was simulated in Group 2 by means of osteotomies. All femora were implanted with a dynamic hip screw and biomechanically tested in 20° adduction under progressively increasing physiologic cyclic axial loading at 2 Hz, starting at 500 N and increasing at a rate of 0.1 N/cycle. Femoral head fragment movements with respect to the shaft were monitored by means of optical motion tracking. RESULTS: Cycles/failure load at 15° varus deformation, 10 mm leg shortening and 15° femoral head rotation around neck axis were 11324 ± 848/1632.4 ± 584.8 N, 11052 ± 1573/1605.2 ± 657.3 N and 11849 ± 1120/1684.9 ± 612.0 N in Group 1, and 10971 ± 2019/1597.1 ± 701.9 N, 10681 ± 1868/1568.1 ± 686.8 N and 10017 ± 4081/1501.7 ± 908.1 N in Group 2, respectively, with no significant differences between the two groups, p ≥ 0.233. CONCLUSION: From a biomechanical perspective, by resulting in more consistent outcomes under dynamic loading, standardized artificial stable pertrochanteric femur fracture creation may be more suitable for orthopaedic implant testing compared to osteotomizing the bone.

A new fluoroscopic view for evaluation of anteromedial cortex reduction quality during cephalomedullary nailing for intertrochanteric femur fractures: the 30° oblique tangential projection.

BACKGROUND: Anteromedial cortex-to-cortex reduction is a key parameter for stable reconstruction of the fracture fragments during the intertrochanteric fracture fixation. This paper introduces the oblique fluoroscopic projection as a novel method to evaluate the quality of anteromedial cortical apposition. METHODS: Three proximal femur specimens were marked with steel wires along five anatomic landmarks: Greater trochanter, Lesser trochanter, Intertrochanteric line, Anterolateral tubercle and the Anteromedial cortical line. After obtaining the standard femoral neck AP and lateral fluoroscopic images, the C-arm was rotated by every 5°increments until a clear tangential view of the antero-medial-inferior corner cortex was observed. 98 cases of intertrochanteric hip fractures were enrolled from April 2018 to October 2019. After fixation with the nails, the intra-operative anteromedial cortex reduction quality was evaluated from the AP, the true lateral, and the new anteromedial oblique fluoroscopic images. The fluoroscopic results were compared with the post-operative 3D-CT reconstruction images. RESULTS: The specimen study showed that internal rotation of the C-arm to approximately 30 ° can remove all the obscure shadows and clearly display the antero-medial-inferior cortical tangent line. Clinically,the positive, neutral and negative apposition of different cortices via intra-operative fluoroscopic images showed79, 19 and 0 cases of medial cortical apposition in AP views; 2, 68 and 28 cases of anterior cortices in lateral views;and 22, 51 and 25cases of anteromedial cortical apposition in oblique views respectively. The post-operative 3D-CT reconstruction images revealed that the final anteromedial cortical contact was noted in 62 cases (63.3%), and lost in 36 cases (36.7%). The overall coincidence rate between intra-operative fluoroscopy and post-operative 3D-CT was 63.3% (62/98) in AP view,79.6% (78/98) in lateral view, and 86.7% (85/98) in oblique view(p < 0.001). Negative cortical apposition in oblique view was highly predictive of a final loss of cortical support on 3D CT (24/25 cases, 96%).And non-negative cortical apposition in oblique view was highly associated with true cortical support on 3D CT images (61/73 cases, 83.6%) (p < 0.001). CONCLUSIONS: Besides the AP and lateral projections, an anteromedial oblique view of 30° certifies to be a very useful means for evaluation of the fracture reduction quality of anteromedial cortical apposition.

Complications of implant removal after healed hip fractures.

INTRODUCTION: Osteosynthesis of pertrochanteric fractures is one of the most frequently performed procedures in orthopaedic trauma care. Auto-dynamization during fracture healing can lead to lateralization of the screw or blade. This can cause debilitating complaints, which sometimes necessitate the removal of the screw or blade. After removal of the implant, we observed spontaneous femoral neck fractures in five patients. This article presents an evaluation of these cases with reference to literature. MATERIALS AND METHODS: Five cases of spontaneous femoral neck fracture (SFNF) after cephalomedullary nail removal are described. A literature search was performed on the incidence of chronic pain and gait impairment associated with auto-dynamization, and on risk factors for dynamization and complications after implant removal. Based on these findings recommendations are made for the prevention of SFNF. RESULTS: Over a 2-year period, we observed five cases of SFNF after cephalomedullary nail removal. In literature, reduced mobility, gait impairment and chronic pain are associated with screw or blade dynamization. Pertrochanteric fractures with AO-type 2 classification were associated with more dynamization and screw lateralization and henceforth more trochanteric pain and gait disturbances. SFNF after cephalomedullary nail removal occurs with an incidence of at least 15%, affecting mostly elderly patients. This severe complication mostly occurs within 3 weeks after implant removal. Risk factors associated with SFNF are pre-existing systemic osteoporosis, stress-shielding, pre-loading of the implant and nail removal of the cephalomedullary implant. CONCLUSION: The clinical indications for implant removal in healed pertrochanteric fractures are not well established and should be restricted to specific cases. After removal of these implants without replacement partial weight-bearing should be advised strictly. Based on our findings it is recommended to replace the cephalomedullary nail with a shorter one, ideally combined with implant augmentation.

[Extensive emphysema after intramedullary nailing of a pertrochanteric fracture : Life-threatening infection or benign complication]. / Ausgeprägtes Emphysem nach Marknagelung einer pertrochantären Fraktur : Lebensbedrohliche Infektion oder benigne Komplikation.

The development of emphysema after intramedullary nailing can represent an easily manageable complication but in the differential diagnostics it could, however, be a life-threatening infection with Clostridium perfringens. This is a report about the case of an extensive subcutaneous and retroperitoneal emphysema, which developed after intramedullary nailing of a pertrochanteric femoral fracture and where such an infection was suspected.

Femoral offset loss and internal arch restoration defect are correlated with intramedullary nail cut-out complications after pertrochanteric fractures: a case-control study.

BACKGROUND AND PURPOSE: In a previous study, we investigated the link between the femoral offset (FO) loss by trochanteric impaction (TI) and cut-out complication occurrence after pertrochanteric fractures. Three major factors are likely to drive to failure after intramedullary nailing (IN): fracture stability, reduction quality and osteosynthesis quality. We wanted to investigate the quality of the fracture reduction through the TI and the neck-shaft angle (NSA) measurement and correlate these parameters with the risk of mechanical failure occurrence. MATERIALS AND METHODS: It was a retrospective multicentric one case-one control match design study with age and gender randomization. The cases presented a mechanical failure of nailing: [Formula: see text] in percentage. Femoral rotation was taken into account, and all TI were rotation-corrected (TIcorrected). Rotation-corrected neck-shaft angles (NSAcorrected) were calculated. The neck-shaft angle gap between the fractured and the healthy sides (NSAgap) was a ratio: [Formula: see text] in percentage. The tip-apex distance (TAD) was measured. Absolute values of TIcorrected and NSAgap were analyzed. RESULTS: Twenty-one cases and 21 controls were examined. The average TIcorrected rate was 30% for the cases and 11% for the controls (p = 0.007). A 13% TIcorrected threshold had maximum specificity and sensitivity, equal to 71%. The average TAD was 27 mm for cases and 19 mm for controls (p = 0.004). The average NSAgap rate was 7% for the case group and 4% for the control group (p = 0.009). The areas under the ROC curves for TIcorrected, TAD and NSAgap were 0.73, 0.73 and 0.66, respectively. INTERPRETATION: Closed reduction and exclusive implantation of IN do not seem optimal in case of FO or NSA restoration failure after pertrochanteric fractures. LEVEL OF EVIDENCE: Level III, case-control study.

Anteromedial cortical support reduction in unstable pertrochanteric fractures: a comparison of intra-operative fluoroscopy and post-operative three dimensional computerised tomography reconstruction.

PURPOSE: Anteromedial cortical support reduction is favourable for secondary stability after limited sliding in unstable pertrochanteric fractures. The aim of this study was to compare the accuracy and agreement between intra-operative fluoroscopy and post-operative 3D reconstruction. MATERIALS AND METHODS: A retrospective analysis of 28 patients (mean 81.6 years) treated with short cephalomedullary nails was performed. All patients had full sets of intra-operative fluoroscopy and post-operative 3D CT images. Observation was focused on the position of the anteromedial cortices of the inferior corner between the head-neck fragment and femoral shaft, and their relationship was categorised into three types: positive, neutral and negative. The percentage of subsequent changes in cortical reduction quality between fluoroscopy and 3D CT was calculated and compared. RESULTS: There were 24 positive (85.7%), four neutral and no negative positions in the anteroposterior (AP) view and one positive, 20 neutral (71.4%) and seven negative positions in the lateral view from fluoroscopy. On post-operative 3D CT images with a full range of rotation, definitive anteromedial cortical contact (positive and neutral support) was observed in 18 cases (64.3%). Ten cases lost the anteromedial cortical buttress. With the posteromedial region of the lesser trochanter detached, a positive AP cortical position combined with a positive/neutral lateral position on fluoroscopy (17 cases) was highly predictive of reliable, definitive cortical support (15 cases, 88.2%) on 3D CT. A negative lateral position on fluoroscopy (seven cases), regardless of the combination in the AP view, was likely to predict the final loss of cortical support (six cases, 85.7%) on 3D CT; a positive/neutral lateral position (21 cases) was only associated with loss of support in four cases (19.1%) (p < 0.05). CONCLUSIONS: A lateral negative position of the anterior cortex on fluoroscopy for unstable pertrochanteric fractures may be highly predictive of post-operative final loss of the anteromedial cortical buttress, which should be avoided during operation.

Complications following proximal femoral locking compression plating in unstable proximal femur fractures: medium-term follow-up.

PURPOSE: To assess the outcome in patients treated with proximal femoral locking compression plate (PF-LCP 4.5/5.0, Synthes©) for unstable inter- and subtrochanteric femoral fractures. METHODS: A retrospective analysis of 16 patients with proximal femur fractures (AO: 31A2: n = 5/32.3%; 31-A3: n = 10/62.5%; 32B1: n = 1/6.3%) treated with a PF-LCP at a Level 1 trauma centre between 2011 and 2015 was conducted. RESULTS: Sixteen patients were available for follow-up with a mean follow-up time of 14 months (range 4-29). Primary outcome included fracture healing, post-operative complications and post-operative ambulatory status. Male to female ratio was 1:1. Mean age was 61 ± 17 years. Union was achieved in a mean of 13.5 ± 3 weeks (range 12-20 weeks). Five patients (31.3%) had implant-associated complications like non-union, malrotation, late implant-associated infection, distal screw fractures and post-traumatic impingement of the hip. Consequently, four patients (25%) had to undergo revision surgery. There was no reported case of secondary varus collapse or cut-out. CONCLUSIONS: Complications occurred in 31.3% (n = 5) in medium-term follow-up after PF-LCP in proximal unstable inter- and subtrochanteric femur fractures. These findings are supported by results of other groups. However, further studies to evaluate risk factors associated with failure of this implant are required.

Arthroplasty for unstable pertrochanteric hip fractures may offer a lower re-operation rate as compared to cephalomedullary nailing.

PURPOSE: Cephalomedullary (CM) nailing is widely used for the treatment of pertrochanteric hip fractures. Fixation failures with CM nailing tend to occur in unstable fracture patterns often necessitating revision surgery. The purpose of this study was to compare the complications and clinical outcomes of primary arthroplasty to CM nailing for the treatment of unstable pertrochanteric hip fractures. METHODS: We conducted an age-, sex-, and fracture type-matched case-controlled study and identified 29 patients who underwent hip arthroplasty for an unstable pertrochanteric fracture (AO/OTA classification type 31A2.2/3 and 31.A3) at our institution. Their outcome was compared to a matched control group of 29 patients treated with a CM nail. RESULTS: There was one major complication in the arthroplasty group (3.4 %), whereas there were six major complications in the nailing group (20.7 %) (P = 0.04). We found no significant difference between the groups with regards to blood loss, operative time, hospitalization time and the number of patients discharged to rehabilitation. Clinical outcome measured with Oxford hip score and SF-12 at the time of final follow-up was not significantly different between the groups. CONCLUSIONS: Arthroplasty is a viable option for treatment of unstable pertrochanteric fractures in an elderly population. Arthroplasty may offer a lower re-operation rate in the treatment of unstable pertrochanteric hip fractures as compared to CM nailing.

The effect of local bone density on mechanical failure after internal fixation of pertrochanteric fractures.

INTRODUCTION: The aim of this prospective study was to investigate the effect of local hip bone density on mechanical failure after fixation of pertrochanteric fractures and to establish possible risk factors for the failures. MATERIALS AND METHODS: A total of 136 consecutive patients presenting a closed unilateral pertrochanteric fracture were enrolled. The patients were treated with a sliding hip screw or an intramedullary nail. Dual energy X-ray absorptiometry measurements for bone density of the contralateral hip were made within 4 weeks postoperatively. Follow-up evaluations on the standard radiographs were documented for any mechanical failure including loss of reduction, screw or blade cut-out, lateral migration of the screw or blade, and implant breakage. Secondary outcomes were also recorded including patient characteristics and fixation construct variables as possible predictors for mechanical failure. RESULTS: At a minimum of 2 years of follow-up, 38 patients were reported with mechanical failure at an estimated risk of 27.9 %. The local bone density measurements for the study population showed no difference between patients with (0.710 g/cm(2)) and without (0.726 g/cm(2)) mechanical failure (P = 0.180). We also observed no significant correlation between local bone density and failure in patients with good fracture reduction (P = 0.862). The multivariate regression analysis identified fracture type (P < 0.001) and quality of fracture reduction (P < 0.001) as being independent predictors for mechanical failure, whereas local bone density was not (P = 0.658). CONCLUSIONS: Local hip bone density does not appear to have a significant influence on mechanical failure after internal fixation of pertrochanteric fractures. Stable fractures and fractures with good reduction are expected to obtain satisfactory outcomes.

Provisional pin fixation: An efficient alternative to manual maintenance of reduction in nailing of intertrochanteric fractures.

INTRODUCTION: During nailing of intertrochanteric fractures, there is always a risk of reduction loss despite achieving an acceptable reduction status after a percutaneous procedure. Most surgeons usually attempted to maintain the reduction with a manual endeavor. However, we experienced varying amounts of intraoperative reduction loss and had to perform readjustments several times. These struggles motivated us to attempt provisional pin fixation as an alternative method. The purpose of this study was to analyze the factors affecting intraoperative reduction loss, especially in comparison between two methods. MATERIALS AND METHODS: Sixty-eight patients with intertrochanteric fractures were included. They were divided into two groups based on the method, by retrospective analysis of the intraoperative c-arm image. In the manual maintenance group, an assistant maintained the instruments during the procedure. In the provisional pin fixation group, the reduction was temporaryily held by a 3.2mm guide pin fixation across the fracture. A displacement of more than one cortical thickness in any plane or angular deformity during any point in the procedure after acceptable reduction was judged as an intraoperative reduction loss. Multivariate logistic regression was used for statistical analysis. RESULTS: The number of cases with intraoperative reduction loss was 18 (18 of 38, 46.1%) in the manual maintenance group and 6 (6 of 30, 20.0%) in the provisional pin fixation group. The odds ratio of intraoperative reduction loss in the manual maintenance group was 5.182 (95% confidence interval, 1.455-18.452) compared with the provisional pin fixation group as the reference. CONCLUSIONS: As a reasonable approach for maintaining reduction, provisional pin fixation can significantly decrease intraoperative reduction loss after percutaneous reduction of intertrochanteric fractures during nailing.

The importance of intramedullary hip nail positioning during implantation for stable pertrochanteric fractures: biomechanical analysis.

PURPOSE: Proximal femoral fractures are among the most commonly sustained fractures. The current treatment of stable proximal femoral fractures located in trochanteric region primarily involves the use of two systems: extramedullary dynamic hip screws and intramedullary hip nails. Given that these fractures are mainly found in the elderly population, the necessity of a repeat, due to failure of the first, may jeopardize the patient's life. Decisive factors contributing to the healing of a fracture (or the failure thereof) include fracture pattern, technical implementation of the operation (i.e., position of the implant), implant's properties and its changes in relation to the surrounding bone tissue during loading. Each screw insertion variant results in damage to various load-bearing bone structures, which can be expected to influence healing quality and stability of newly formed bone. METHOD: With the aid of a numerical model and finite element methods, the authors analyzed several different positions of IMHN/PFH-nails in the proximal femur, with the objective of determining positions with an increased risk of failure. RESULTS AND CONCLUSION: In model situations, it has been shown that in stable fractures results do not depend on absolutely precise positioning and small deflections in the nails and neck screws positions do not significantly increase the risk of failure for the entire fixation. Damage to load-bearing structures relative to various implant placements does not impact the resultant overall fixation stability. Therefore, it is not necessary to re-introduce implants in the ideal position, which can lead to reduced patient radiation doses during surgery.

Effect of varus and valgus alignment on implant loading after proximal femur fracture fixation.

INTRODUCTION: More than 10 % of proximal femur fractures repaired with either a sliding hip screw and side plate (SHS-P) or a sliding hip screw and intramedullary nail (SHS-IMN) demonstrate varus malreduction. The purpose of this study was to compare the effect of varus or valgus loading on comminuted intertrochanteric fractures repaired with SHS-P or SHS-IMN constructs. METHODS: Unstable intertrochanteric fractures with segmental comminution were generated in 12 cadaver proximal femurs, six of which were fixed with an SHS-P and six with an SHS-IMN. Both implants had a strain gauge at the lag screw-nail-plate interface to assess implant load bearing. The load on the implants was measured with the specimens in neutral position and at 5°, 10°, and 15° of varus and valgus. RESULTS: Loads on both SHS-IMN and SHS-P constructs were significantly increased when loading the implants in varus and significantly decreased when loading the implants in valgus. Unlike the SHS-IMN, the SHS-P trended toward increased load bearing at 15° varus (159.1 vs. 118.5 %, P = .065) and trended toward less load bearing at 15° valgus (42.3 vs. 59.8 %, P = .06). CONCLUSIONS: Regardless of implant choice, avoiding varus loading on the fixation construct reduces the load on the implant. SHS-P constructs may be more affected by varus or valgus malalignment than SHS-IMN constructs.