The use of a ti-ni shape memory alloy ring bone fixator during the retrograde nailing of supracondylar femoral fractures

Interventions for treating fractures of the distal femur in adults

BACKGROUND

Fractures of the distal femur (the far end of the thigh bone just above the knee) are a considerable cause of morbidity. Various different surgical and non-surgical treatments have been used in the management of these injuries but the best treatment remains unknown.

OBJECTIVES

To evaluate the benefits and harms of interventions for treating fractures of the distal femur in adults.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was October 2021.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials in adults comparing interventions for treating fractures of the distal femur. Interventions included surgical implants (retrograde intramedullary nail (RIMN), fixed-angle devices, non-locking plate fixation, locking plate, internal fixation, distal femoral replacement, mono-axial plates, poly-axial plates and condylar buttress plates) and non-surgical management.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our critical outcomes were validated patient-reported outcome measures (PROMs), direct adverse events, participant-reported quality of life (QoL) and pain scores. Our other important outcomes were adverse events indirectly related to intervention, symptomatic non-union, malunion and resource use. We used GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We included 14 studies with 753 participants: 13 studies compared different surgical interventions, and one study compared surgical with non-surgical management. Here, we report the effects for RIMN compared with locking plates. Three studies (221 participants) reported this comparison; it included the largest study population and these are the two most commonly used devices in contemporary orthopaedic trauma practice. Studies used three different tools to assess PROMs. We found very-low certainty evidence for lower Disability Rating Index scores after RIMN at short-term follow-up favouring RIMN (mean difference (MD) -21.90, 95% confidence interval (CI) -38.16 to -5.64; 1 study, 12 participants) and low-certainty evidence of little or no difference at long-term follow-up (standardised mean difference (SMD) -0.22, 95% CI -0.50 to 0.06; 2 studies, 198 participants). Re-expressing the SMD of the long-term follow-up data to Knee Society Score (KSS) used by one study found no clinical benefit of RIMN, based on a minimal clinically important difference of 9 points (MD 2.47, 95% CI -6.18 to 0.74). The effect on QoL was very uncertain at four months (MD 0.01, 95% CI -0.42 to 0.44; 1 study, 14 participants) and one year (MD 0.10, 95% CI -0.01 to 0.21; 1 study, 156 participants); this evidence was very low certainty. For direct adverse events, studies reported reoperation, loss of fixation, superficial and deep infection, haematoma formation and implant loosening. Effects for all events were imprecise with the possibility of benefit or harm for both treatments. We considered reoperation the most clinically relevant. There was very low-certainty evidence of little or no difference in reoperation between the two implants (risk ratio (RR) 1.48, 95% CI 0.55 to 4.00; 1 study, 104 participants). No studies reported pain.  For other important outcomes, we noted that people treated with RIMN may be more likely to have varus/valgus deformity (RR 2.18, 95% CI 1.09 to 4.37; 1 study, 33 participants; low-certainty evidence). However, we found no evidence of any important differences between treatments in terms of bony union, indirect adverse events, or resource use. Other comparisons of surgical interventions included in the review were: RIMN versus single fixed-angle device (3 studies, 175 participants); RIMN versus non-locking plate fixation (1 study, 18 participants); locking plate versus single fixed-angle device (2 studies, 130 participants); internal fixation versus distal femoral replacement (1 study, 23 participants); mono-axial plates versus poly-axial plates (2 studies, 67 participants); mono-axial plate versus condylar buttress plate (1 study, 78 participants). The certainty of the evidence for outcomes in these comparisons was low to very low, and most effect estimates were imprecise.

AUTHORS' CONCLUSIONS

This review highlights the major limitations of the available evidence concerning current treatment interventions for fractures of the distal femur. The currently available evidence is incomplete and insufficient to inform clinical practice. Priority should be given to randomised controlled trials comparing contemporary treatments for people with fractures of the distal femur. At a minimum, these should report validated patient-reported functional and quality-of-life outcomes at one and two years, with an agreed core outcome set. All trials should be reported in full using the CONSORT guidelines.

Interventions for treating fractures of the distal femur in adults

BACKGROUND

Fractures of the distal femur (the part of the thigh bone nearest the knee) are a considerable cause of morbidity. Various different surgical and non-surgical treatments have been used in the management of these injuries but the best treatment remains controversial.

OBJECTIVES

To assess the effects (benefits and harms) of interventions for treating fractures of the distal femur in adults.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (9 September 2014); the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2014, Issue 8); MEDLINE (1946 to August week 4 2014); EMBASE (1980 to 2014 week 36); World Health Organization (WHO) International Clinical Trials Registry Platform (January 2015); conference proceedings and reference lists without language restrictions.

SELECTION CRITERIA

Randomised and quasi-randomised controlled clinical trials comparing interventions for treating fractures of the distal femur in adults. Our primary outcomes were patient-reported outcome measures (PROMs) of knee function and adverse events, including re-operations.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies and performed data extraction and risk of bias assessment. We assessed treatment effects using risk ratios (RR) or mean differences (MD) and, where appropriate, we pooled data using a fixed-effect model.

MAIN RESULTS

We included seven studies that involved a total of 444 adults with distal femur fractures. Each of the included studies was small and assessed to be at substantial risk of bias, with four studies being quasi-randomised and none of the studies using blinding in outcome assessment. All studies provided an incomplete picture of outcome. Based on GRADE criteria, we assessed the quality of the evidence as very low for all reported outcomes, which means we are very uncertain of the reliability of these results.One study compared surgical (dynamic condylar screw (DCS) fixation) and non-surgical (skeletal traction) treatment in 42 older adults (mean age 79 years) with displaced fractures of the distal femur. This study, which did not report on PROMs, provided very low quality evidence of little between-group differences in adverse events such as death (2/20 surgical versus 1/20 non-surgical), re-operation or repeat procedures (1/20 versus 3/20) and other adverse effects including delayed union. However, while none of the findings were statistically significant, there were more complications such as pressure sores (0/20 versus 4/20) associated with prolonged immobilisation in the non-surgical group, who stayed on average one month longer in hospital.The other six studies compared different surgical interventions. Three studies, including 159 participants, compared retrograde intramedullary nail (RIMN) fixation versus DCS or blade-plate fixation (fixed-angle devices). None of these studies reported PROMS relating to function. None of the results for the reported adverse events showed a difference between the two implants. Thus, although there was very low quality evidence of a higher risk of re-operation in the RIMN group, the 95% confidence interval (CI) also included the possibility of a higher risk of re-operation for the fixed-angle device (9/83 RIMN versus 4/96 fixed-angle device; 3 studies: RR 1.85, 95% CI 0.62 to 5.57). There was no clinically important difference between the two groups found in quality of life assessed using the 36-item Short Form in one study (23 fractures).One study (18 participants) provided very low quality evidence of there being little difference in adverse events between RIMN and non-locking plate fixation. One study (53 participants) provided very low quality evidence of a higher risk of re-operation after locking plate fixation compared with a single fixed-angle device (6/28 locking plate versus 1/25 fixed-angle device; RR 5.36, 95% CI 0.69 to 41.50); however, the 95% CI also included the possibility of a higher risk of re-operation for the fixed-angle device. Neither of these trials reported on PROMs.The largest included study, which reported outcomes in 126 participants at one-year follow-up, compared RIMN versus locking plate fixation; both implants are commonly used in current practice. None of the between-group differences in the reported outcomes were statistically significant; thus the CIs crossed the line of no effect. There was very low quality evidence of better patient-reported musculoskeletal function in the RIMN group based on Short Musculoskeletal Function Assessment (0 to 100: best function) scores (e.g. dysfunction index: MD -5.90 favouring RIMN, 95% CI -15.13 to 3.33) as well as quality of life using the EuroQoL-5D Index (0 to 1: best quality of life) (MD 0.10 favouring RIMN, 95% CI -0.01 to 0.21). The CIs for both results included a clinically important effect favouring RIMN but also a clinically insignificant effect in favour of locking plate fixation.

AUTHORS' CONCLUSIONS

This review highlights the major limitations of the available evidence concerning current treatment interventions for fractures of the distal femur. The currently available evidence is incomplete and insufficient to inform current clinical practice. Priority should be given to a definitive, pragmatic, multicentre randomised controlled clinical trial comparing contemporary treatments such as locked plates and intramedullary nails. At minimum, these should report validated patient-reported functional and quality-of-life outcomes at one and two years. All trials should be reported in full using the CONSORT guidelines.

Treatment of patella fracture by claw-like shape memory alloy

INTRODUCTION

Titanium-nickel shape memory alloy (Ti-Ni SMA) is characterized by shape-memory effect, super-elasticity, excellent fatigue behavior, corrosion resistance, acceptable biocompatibility and high damping capacity.

MATERIALS AND METHODS

Claw-like Ti-Ni SMA fixator (SMA-claw) has been used to treat transverse fracture of patella. 29 patients (19 males, 10 females) aged from 21 to 71 years old (averaged 43.0 years old) have been received open reduction and internal fixation with SMA-claw from January 2011 to December 2011. After operation, patients have been received gradual knee function exercises, followed by radiographic analysis and Lysholm Knee Score at 1, 2, 3, 6, 9 and 12 months postoperation.

RESULTS

The mean follow-up time was 11.48 months (25 patients finished, 1 lost after 6 months and 3 lost after 9 months). Radiographic bone union occurred at 2 months (7 patients) or 3 months (22 patients). Satisfied range of motion for the knee joint has been observed with 1.90/141.72° (hyperextension/flexion) at 3 months, 4.83/143.97° at 6 months, 4.82/144.82° at 9 months and 5.2/145° at 12 months postsurgery.

CONCLUSION

The Ti-Ni SMA-claw fixator produced good osteosynthesis effect by continuous recovery stress with relatively simple and minimally invasive handling process, which can be introduced as an alternative to traditional tension band technique for treatment of patellar transverse fracture.