Biases in a randomized comparison of three types of screw fixation in displaced femoral neck fractures

Surgical interventions for treating intracapsular hip fractures in older adults: a network meta-analysis

BACKGROUND

Hip fractures are a major healthcare problem, presenting a considerable challenge and burden to individuals and healthcare systems. The number of hip fractures globally is rising rapidly. The majority of intracapsular hip fractures are treated surgically.

OBJECTIVES

To assess the relative effects (benefits and harms) of all surgical treatments used in the management of intracapsular hip fractures in older adults, using a network meta-analysis of randomised trials, and to generate a hierarchy of interventions according to their outcomes.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Web of Science, and five other databases in July 2020. We also searched clinical trials databases, conference proceedings, reference lists of retrieved articles and conducted backward-citation searches.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs comparing different treatments for fragility intracapsular hip fractures in older adults. We included total hip arthroplasties (THAs), hemiarthroplasties (HAs), internal fixation, and non-operative treatments. We excluded studies of people with hip fracture with specific pathologies other than osteoporosis or resulting from high-energy trauma.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion. One review author completed data extraction which was checked by a second review author. We collected data for three outcomes at different time points: mortality and health-related quality of life (HRQoL) - both reported within 4 months, at 12 months, and after 24 months of surgery, and unplanned return to theatre (at end of study follow-up). We performed a network meta-analysis (NMA) with Stata software, using frequentist methods, and calculated the differences between treatments using risk ratios (RRs) and standardised mean differences (SMDs) and their corresponding 95% confidence intervals (CIs). We also performed direct comparisons using the same codes.

MAIN RESULTS

We included 119 studies (102 RCTS, 17 quasi-RCTs) with 17,653 participants with 17,669 intracapsular fractures in the review; 83% of fractures were displaced. The mean participant age ranged from 60 to 87 years and 73% were women.  After discussion with clinical experts, we selected 12 nodes that represented the best balance between clinical plausibility and efficiency of the networks: cemented modern unipolar HA, dynamic fixed angle plate, uncemented first-generation bipolar HA, uncemented modern bipolar HA, cemented modern bipolar HA, uncemented first-generation unipolar HA, uncemented modern unipolar HA, THA with single articulation, dual-mobility THA, pins, screws, and non-operative treatment. Seventy-five studies (with 11,855 participants) with data for at least two of these treatments contributed to the NMA. We selected cemented modern unipolar HA as a reference treatment against which other treatments were compared. This was a common treatment in the networks, providing a clinically appropriate comparison. In order to provide a concise summary of the results, we report only network estimates when there was evidence of difference between treatments. We downgraded the certainty of the evidence for serious and very serious risks of bias and when estimates included possible transitivity, particularly for internal fixation which included more undisplaced fractures. We also downgraded for incoherence, or inconsistency in indirect estimates, although this affected few estimates. Most estimates included the possibility of benefits and harms, and we downgraded the evidence for these treatments for imprecision.  We found that cemented modern unipolar HA, dynamic fixed angle plate and pins seemed to have the greatest likelihood of reducing mortality at 12 months. Overall, 23.5% of participants who received the reference treatment died within 12 months of surgery. Uncemented modern bipolar HA had higher mortality than the reference treatment (RR 1.37, 95% CI 1.02 to 1.85; derived only from indirect evidence; low-certainty evidence), and THA with single articulation also had higher mortality (network estimate RR 1.62, 95% CI 1.13 to 2.32; derived from direct evidence from 2 studies with 225 participants, and indirect evidence; very low-certainty evidence). In the remaining treatments, the certainty of the evidence ranged from low to very low, and we noted no evidence of any differences in mortality at 12 months.  We found that THA (single articulation), cemented modern bipolar HA and uncemented modern bipolar HA seemed to have the greatest likelihood of improving HRQoL at 12 months. This network was comparatively sparse compared to other outcomes and the certainty of the evidence of differences between treatments was very low. We noted no evidence of any differences in HRQoL at 12 months, although estimates were imprecise. We found that arthroplasty treatments seemed to have a greater likelihood of reducing unplanned return to theatre than internal fixation and non-operative treatment. We estimated that 4.3% of participants who received the reference treatment returned to theatre during the study follow-up. Compared to this treatment, we found low-certainty evidence that more participants returned to theatre if they were treated with a dynamic fixed angle plate (network estimate RR 4.63, 95% CI 2.94 to 7.30; from direct evidence from 1 study with 190 participants, and indirect evidence). We found very low-certainty evidence that more participants returned to theatre when treated with pins (RR 4.16, 95% CI 2.53 to 6.84; only from indirect evidence), screws (network estimate RR 5.04, 95% CI 3.25 to 7.82; from direct evidence from 2 studies with 278 participants, and indirect evidence), and non-operative treatment (RR 5.41, 95% CI 1.80 to 16.26; only from indirect evidence). There was very low-certainty evidence of a tendency for an increased risk of unplanned return to theatre for all of the arthroplasty treatments, and in particular for THA, compared with cemented modern unipolar HA, with little evidence to suggest the size of this difference varied strongly between the arthroplasty treatments.

AUTHORS' CONCLUSIONS

There was considerable variability in the ranking of each treatment such that there was no one outstanding, or subset of outstanding, superior treatments. However, cemented modern arthroplasties tended to more often yield better outcomes than alternative treatments and may be a more successful approach than internal fixation. There is no evidence of a difference between THA (single articulation) and cemented modern unipolar HA in the outcomes measured in this review. THA may be an appropriate treatment for a subset of people with intracapsular fracture but we have not explored this further.

Internal fixation implants for intracapsular hip fractures in older adults

BACKGROUND

Hip fractures are a major healthcare problem, presenting a huge challenge and burden to patients, healthcare systems and society. The increased proportion of older adults in the world population means that the absolute number of hip fractures is rising rapidly across the globe. The majority of hip fractures are treated surgically. This review evaluates evidence for types of internal fixation implants used in joint-preserving surgery for intracapsular hip fractures.

OBJECTIVES

To determine the relative effects (benefits and harms) of different implants for the internal fixation of intracapsular hip fractures in older adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Web of Science, Cochrane Database of Systematic Reviews, Epistemonikos, Proquest Dissertations and Theses, and National Technical Information Service in July 2020. We also searched clinical trials databases, conference proceedings, reference lists of retrieved articles and conducted backward-citation searches.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs comparing implants used for internal fixation of fragility intracapsular proximal femoral fractures in older adults. Types of implants were smooth pins (these include pins with fold-out hooks), screws, or fixed angle plates. We excluded studies in which all or most fractures were caused by specific pathologies other than osteoporosis or were the result of a high energy trauma.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion. One review author extracted data and assessed risk of bias which was checked by a second review author. We collected data for seven outcomes: activities of daily living (ADL), delirium, functional status, health-related quality of life (HRQoL), mobility, mortality (reported within four months of surgery as early mortality, and at 12 months since surgery), and unplanned return to theatre for treating a complication resulting directly or indirectly from the primary procedure (such as deep infection or non-union). We assessed the certainty of the evidence for these outcomes using GRADE.

MAIN RESULTS

We included 38 studies (32 RCTs, six quasi-RCTs) with 8585 participants with 8590 intracapsular fractures. The mean ages of participants in the studies ranged from 60 to 84 years; 73% were women, and 38% of fractures were undisplaced. We report here the findings of the four main comparisons, which were between different categories of implants. We downgraded the certainty of the outcomes for imprecision (when data were available from insufficient numbers of participants or the confidence interval (CI) was wide), study limitations (e.g. high or unclear risks of bias), and inconsistency (when we noted substantial levels of statistical heterogeneity). Smooth pins versus fixed angle plate (four studies, 1313 participants) We found very low-certainty evidence of little or no difference between the two implant types in independent mobility with no more than one walking stick (1 study, 112 participants), early mortality (1 study, 383 participants), mortality at 12 months (2 studies, 661 participants), and unplanned return to theatre (3 studies, 736 participants). No studies reported on ADL, delirium, functional status, or HRQoL. Screws versus fixed angle plates (11 studies, 2471 participants) We found low-certainty evidence of no clinically important differences between the two implant types in functional status using WOMAC (MD -3.18, 95% CI -6.35 to -0.01; 2 studies, 498 participants; range of scores from 0 to 96, lower values indicate better function), and HRQoL using EQ-5D (MD 0.03, 95% CI 0.00 to 0.06; 2 studies, 521 participants; range -0.654 (worst), 0 (dead), 1 (best)). We also found low-certainty evidence showing little or no difference between the two implant types in mortality at 12 months (RR 1.04, 95% CI 0.83 to 1.31; 7 studies, 1690 participants), and unplanned return to theatre (RR 1.10, 95% CI 0.95 to 1.26; 11 studies, 2321 participants). We found very low-certainty evidence of little or no difference between the two implant types in independent mobility (1 study, 70 participants), and early mortality (3 studies, 467 participants). No studies reported on ADL or delirium. Screws versus smooth pins (seven studies, 1119 participants) We found low-certainty evidence of no or little difference between the two implant types in mortality at 12 months (RR 1.07, 95% CI 0.85 to 1.35; 6 studies, 1005 participants; low-certainty evidence). We found very low-certainty evidence of little or no difference between the two implant types in early mortality (3 studies, 584 participants) and unplanned return to theatre (5 studies, 862 participants). No studies reported on ADL, delirium, functional status, HRQoL, or mobility. Screws or smooth pins versus fixed angle plates (15 studies, 3784 participants) In this comparison, we combined data from the first two comparison groups. We found low-certainty evidence of no or little difference between the two groups of implants in mortality at 12 months (RR 1.04, 95% CI.083 to 1.31; 7 studies, 1690 participants) and unplanned return to theatre (RR 1.02, 95% CI 0.88 to 1.18; 14 studies, 3057 participants). We found very low-certainty evidence of little or no difference between the two groups of implants in independent mobility (2 studies, 182 participants), and early mortality (4 studies, 850 participants). We found no additional evidence to support the findings for functional status or HRQoL as reported in 'Screws versus fixed angle plates'. No studies reported ADL or delirium.

AUTHORS' CONCLUSIONS

There is low-certainty evidence that there may be little or no difference between screws and fixed angle plates in functional status, HRQoL, mortality at 12 months, or unplanned return to theatre; and between screws and pins in mortality at 12 months. The limited and very low-certainty evidence for the outcomes for which data were available for the smooth pins versus fixed angle plates comparison, as well as the other outcomes for which data were available for the screws and fixed angle plates, and screws and pins comparisons means we have very little confidence in the estimates of effect for these outcomes. Additional RCTs would increase the certainty of the evidence. We encourage such studies to report outcomes consistent with the core outcome set for hip fracture, including long-term quality of life indicators such as ADL and mobility.

Optimal Technical Factors During Operative Management of Low-Energy Femoral Neck Fractures

OBJECTIVE

To determine if cancellous screw (CS) and sliding hip screw (SHS) technical factors during low-energy femoral neck fracture fixation affects a 24-month revision surgery rate and health-related quality of life (HRQL).

DESIGN

Prospective randomized controlled study.

SETTING

International, multicenter.

PATIENTS

Eight hundred ninety-eight femoral neck fracture patients age 50 years and older.

INTERVENTION

Patients were randomized to fracture stabilization with either CSs or a SHS device as part of the Fixation Using Alternative Implants for the Treatment of Hip Fractures (FAITH) trial. CS technical factors analyzed included screw diameter, short versus long screw threads, screw number and formation, screw orientation, and washer use. SHS technical factors studied were side plate length, supplemental screw use, lag screw position, and tip-apex distance.

MAIN OUTCOME MEASUREMENTS

Revision surgeries within 24 months to promote fracture healing, relieve pain, treat infection, or improve function. In addition, HRQL measures were collected, including the SF-12 Physical Component Score and Western Ontario and McMaster Universities Osteoarthritis Index.

RESULTS

The 3-screw inverted triangle pattern had a significantly lower revision surgery rate than a 3-screw triangle formation (P = 0.004). No other CS or SHS technical factors were predictive of revision surgery or affected a patient's HRQL (P > 0.05).

CONCLUSIONS

A 3-screw inverted triangle pattern was superior to a 3-screw triangle formation. However, injury and patient factors such as fracture displacement, age, smoking status and sex play a more significant role in clinical outcomes for low-energy femoral neck fracture treatment.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Similar outcome of femoral neck fractures treated with Pinloc or Hansson Pins: 1-year data from a multicenter randomized clinical study on 439 patients

Background and purpose - There are few reports on the efficiency of the Hansson Pinloc System (Pinloc) for fixation of femoral neck fractures. We compare Pinloc with the commonly used Hansson Pin System in a randomized clinical trial. The primary outcome measure is non-union or avascular necrosis within 2 years. We now report fracture failures and reoperations within the first year.Patients and methods - Between May 2014 and February 2017, 439 patients were included in the study. They were above 50 years of age and treated for a femoral neck fracture at 9 orthopedic departments in Sweden. They were randomized to either Pinloc or Hansson pins. The fractures were grouped as (a) non-displaced regardless of age, (b) displaced in patients < 70 years, or (c) ≥ 70 years old, but deemed unfit to undergo arthroplasty. Follow-up with radiographs and outpatient visits were at 3 and 12 months. Failure was defined as early displacement/non-union, symptomatic segmental collapse, or deep infection.Results - 1-year mortality was 11%. Of the 325 undisplaced fractures, 12% (21/169) Pinloc and 13% (20/156) Hansson pin patients had a failure during the first year. The reoperation frequencies were 10% (16/169) and 8% (13/156) respectively. For the 75 patients 50-69 years old with displaced fractures, 11/39 failures occurred in the Pinloc group and 11/36 in the Hansson group, and 8/39 versus 9/36 patients were reoperated. Among those 39 patients ≥ 70 years old, 7/21 failures occurred in the Pinloc group and 4/18 in the Hansson group. Reoperation frequencies were 4/21 for Pinloc and 3/18 for the Hansson pin patients. No statistically significant differences were found in any of the outcomes between the Pinloc and Hansson groups.Interpretation - We found no advantages with Pinloc regarding failure or reoperation frequencies in this 1-year follow-up.

Optimum Configuration of Cannulated Compression Screws for the Fixation of Unstable Femoral Neck Fractures: Finite Element Analysis Evaluation

Objectives

In the present study, we evaluated the mechanical outcome of different configurations of cannulated compression screws for the fixation of Pauwels type III femoral neck fracture and the stress distribution around the holes corresponding to fixation protocol after screws removal.

Methods

The Pauwels type III of femoral neck fracture was created in 3-matic software and the models of cannulated compression screws were constructed using UG-NX software. Five fixation systems were assembled to the fracture models. Abaqus software was used to perform the process of finite element analysis. Values of stress distribution, maximum stress, model principal strains of proximal fragment, and stress distribution around the holes of femur model were recorded.

Results

Stress of cannulated compression screws was intensely focused on the middle area of the screw near the fragment of each group. Inverted triangle model showed the highest peak stress on screws under different phases of load. Each screw dispersed some stresses, but at least one underwent the peak stress. Fracture model fixed by inverted triangle configuration showed the lowest volume of yielding strain in the proximal fragment. The area of higher stress around the holes was largest after triangle screws removal when compared with other four models.

Conclusions

Our study indicated that different cannulated compression screws fixation configurations for the unstable femoral neck fractures showed the different mechanical efficiency. Inverted triangular configuration showed the mechanical advantage and being less likely to cutout. The fixation strategy of triangle configuration was least recommended if patients tended to remove the implants.

Finite element analysis of different configurations of fully threaded cannulated screw in the treatment of unstable femoral neck fractures

BACKGROUND

In the present study, we evaluated the mechanical outcome of different configurations formed by fully threaded screws and partially threaded screws in the treatment of unstable femoral neck fracture.

METHODS

The Pauwels type III unstable femoral fracture and the models of the fully threaded screw and partially threaded screw were constructed in 3-matic software and UG-NX software respectively. We then assembled the different screw configurations to the fracture model separately to form the fixation models. After meshing the models' elements, we used Abaqus software to perform the finite element analysis. Parameters of von Mises stress distribution on the screws, peak stress, displacement between fracture fragments, and model principal strains in cancellous bone were reported.

RESULTS

Our results indicated that the peak von Mises stresses of screws was concentrated in the middle surface of the screw near the fracture line in each group. Peak stress value of the implants was highest in the model of triangle with posterior single screw. And the lowest stress values were observed in the triangular model. Fully threaded screw in each group underwent the most stress while partially threaded screw underwent a little bit of stress. Lowest displacement was observed in the triangular model. The volume of bone susceptible to yielding in the femoral neck region was the lowest for triangular configuration.

CONCLUSIONS

For unstable femoral neck fractures, superior results were obtained by stabilizing the fracture with triangular configuration formed by one superior partially threaded screw and two inferior fully threaded screws. This study will require clinical confirmation as to its practicality in the management of unstable femoral fractures.

Clinical results of surgical treatment for femoral neck fractures with the Targon® FN

84 cases (male 15 cases, female 69 cases) of intracapsular femoral neck fractures treated with the Targon^® FN (TFN) were available for review. Mean patient age was 74.0 years (range 36-100 years). 55 fractures were undisplaced whereas 29 were displaced. Mean follow-up term was 16.4 months. We surveyed patient mobility before injury and after operation as well as postoperative complications. On a four-stage mobility scale we found 3/55 patients with undisplaced fractures loosing mobility by more than one grade (5.5%), whereas 5/29 (17.2%) displayed this kind of functional decline after displaced fractures. Overall postoperative complication rate was 10.7% (9 cases). These complications included nonunion (1 case), avascular necrosis (7 cases) and peri-implant fracture (1case). Internal fixation with the TFN seems to have an acceptable complication rate in both undisplaced and displaced fractures compared to other recent studies.

OSTEOSYNTHESIS OF FEMORAL NECK FRACTURES: TWO OR THREE SCREWS?

Objectives: To evaluate the efficacy of osteosynthesis on femoral neck fractures using two instead of three screws. Methods: Thirty-nine fractures were retrospectively evaluated, divided into groups in which two screws were used in parallel (n = 28) or three screws (n =11) in an inverted triangle configuration (in accordance with the AO technique). The patients were then followed up until reaching the outcome of either consolidation or failure. Results: In the group in which two screws were used, consolidation was observed in 23 of the 28 fractures (82%). In the group in which three screws were used, consolidation was observed in 6 of the 11 fractures (55%). There was no statistically significant difference between these percentages. Conclusion: There was no difference in the prognosis for these fractures when treated using two screws in parallel or three screws in an inverted triangle in accordance with the AO technique. Further studies are needed in order to establish a definitive conclusion.

Biomechanical evaluation of the expansive cannulated screw for fixation of femoral neck fractures

BACKGROUND

Femoral neck fracture is one of the common clinical traumas, especially amongst elder patients. This study aims to test, compare and evaluate the bone-screw interface strengths, the fatigue strengths, and the stabilities of our newly designed expansive cannulated screw (ECS) and the common cannulated compression screw (CCS) in the fixation of femoral neck fracture, which is a summary of recent research.

METHODS

Twenty-four pairs (48) of fresh femur specimens were randomly divided into four groups with six pairs (12) in each. To simulate one-legged standing, the maximum compressive strength and the single-screw axial pull-out force were compared between the fixed femoral necks treated with two ECSs and two CCSs, two ECSs and three CCSs or three ECSs and three CCSs, respectively. The screws were also subjected to 1,000,000 cycles of a loaded fatigue test and the results were recorded.

FINDINGS

When the same number of screws was used, the ECS showed significantly greater maximum compressive strength than the CCS (P<0.05), but no significant difference in fixation effectiveness was detected between the two ECSs and the three CCSs groups. The maximum axial pull-out strength of the ECS was also significantly greater that of the CCS (P<0.01); however, there was no sign of fatigue in both the ECS and CCS after 1,000,000 cycles of loaded fatigue test.

INTERPRETATION

The ECS shows better fixation performance than the currently and commonly used CCS; under certain circumstances, fixation with two ECSs can achieve the same effect as that with traditional three CCSs.

[Percutaneous screw osteosynthesis of femoral neck fractures in the elderly. Subtrochanteric fractures as severe complications]

Percutaneous osteosynthesis by cannulated screws is a well established method for the treatment of non-displaced femoral neck fractures, especially in elderly patients with comorbidities due to low operative invasiveness. Optimal screw placement is still under discussion. There are only few literature references concerning the complication of subtrochanteric femoral fractures. We performed a review of the literature and a retrospective analysis of our patients treated by this form of osteosythesis from 01.04.2004 to 30.09.2009 searching for screw placement and the incidence of subtrochanteric femoral fractures. This complication was found in 2 of our 35 patients (5.7%) without adequate trauma, such as a stumble or fall having occurred.

Optimum configuration of cannulated hip screws for the fixation of intracapsular hip fractures: a biomechanical study

The radiographs of a sample of patients who had canulated hip screw fixation for intracapsular femoral neck fractures were reviewed in our region. There were six different types of configurations used in these fixations which are divided into two groups: (I) triangular configurations, consisting of two parallel screws with a third screw placed either superiorly, inferiorly, anteriorly or posteriorly; and (II) linear configurations with two or three screws in a vertical line. In our study, we tested the relative strength of each configuration in a laboratory setting using synthetic bone models. Statistical analysis, at 5% significance level, using two-way ANOVA and post-hoc test was carried out to test the differences of the results between the configurations.Our results clearly show that the triangular configurations had a higher peak load, higher ultimate load, less displacement and more energy absorption before failure than other configurations.

Evidence‐based guidelines for fixing broken hips: an update

OBJECTIVE

To update evidence-based guidelines for the treatment of proximal femoral fractures published in the Journal in 1999.

DATA SOURCES

Systematic literature search of MEDLINE, CINAHL and EMBASE from January 1996 to September 2001 and the Cochrane Database of Systematic Reviews (most recent issue searched - Issue 2, 2002).

STUDY SELECTION

Randomised controlled trials and meta-analyses of all aspects of acute-care hospital treatment and rehabilitation of proximal femoral fractures among subjects aged 50 years and over with proximal femoral fractures not associated with metastatic disease or multiple trauma.

DATA EXTRACTION

All studies were read independently by two reviewers. Reviewers recorded individual study results, and an assessment of study quality and treatment conclusions according to Cochrane Collaboration protocols. If necessary, a third review was performed to reach consensus.

RESULTS

93 new studies were identified and 82 met our inclusion criteria. Recommendations for thromboprophylaxis, anaesthesia, surgical fixation of fractures and nutritional status have been altered to incorporate new evidence. Recommendations have been added regarding postoperative blood transfusion, the management of subtrochanteric fractures, and the type of surgical swabs which should be used.

CONCLUSIONS

Although there have been few significant changes to the previous recommendations, updating the guidelines has required substantial effort. The common clinical problem of hip fracture should be treated according to the most up-to-date evidence to achieve the best possible outcomes and optimal utilisation of limited resources. Guideline updates also require resourcing.

Internal fixation implants for intracapsular proximal femoral fractures in adults

BACKGROUND

Numerous different implants with screws, pins and side plates have been used for the internal fixation of intracapsular hip fractures.

OBJECTIVES

To determine from randomised trials which implant is superior for the internal fixation of intracapsular proximal femoral fractures.

SEARCH STRATEGY

We searched the Cochrane Musculoskeletal Injuries Group specialised register. The date of the most recent search was December 2000.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing different implants for the internal fixation of intracapsular hip fractures in adults.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality, by use of a ten item scale, and extracted data. Additional information was sought from trialists. After grouping by implant type, comparable groups of trials were subgrouped and where appropriate, data were pooled using the fixed effects model.

MAIN RESULTS

Twenty-seven studies involving 5269 participants (5274 fractures) were included in the study. Considerable variation in the quality of methodology between studies was found and biases due to familiarity with some of the implants were noted. None of the implants tested were found to be significantly superior for any of the outcome measures related to fracture healing complications or mortality. The sliding hip screw was found to take longer to insert and to have an increased operative blood loss compared with multiple screws or pins.

REVIEWER'S CONCLUSIONS

No clear conclusions can be made on the choice of implant for internal fixation of intracapsular fractures from the available evidence within randomised trials.