MicroRNAs (miRNAs ) are small non-coding RNAs that regulate gene expression. We hypothesised that the functions of certain miRNAs and changes to their patterns of expression may be crucial in the pathogenesis of nonunion. Healing fractures and atrophic nonunions produced by periosteal cauterisation were created in the femora of 94 rats, with 1:1 group allocation. At post-fracture days three, seven, ten, 14, 21 and 28, miRNAs were extracted from the newly generated tissue at the fracture site. Microarray and real-time polymerase chain reaction (PCR) analyses of day 14 samples revealed that five miRNAs, miR-31a-3p, miR-31a-5p, miR-146a-5p, miR-146b-5p and miR-223-3p, were highly upregulated in nonunion. Real-time PCR analysis further revealed that, in nonunion, the expression levels of all five of these miRNAs peaked on day 14 and declined thereafter.

Our results suggest that miR-31a-3p, miR-31a-5p, miR-146a-5p, miR-146b-5p and miR-223-3p may play an important role in the development of nonunion. These findings add to the understanding of the molecular mechanism for nonunion formation and may lead to the development of novel therapeutic strategies for its treatment.

Cite this article: Bone Joint J 2015; 97-B:1144–51.

Objectives

The purpose of this study was to compare the results and complications of tibial lengthening over an intramedullary nail with treatment using the traditional Ilizarov method.

We analysed retrospectively the risk factors leading to femoral overgrowth after flexible intramedullary nailing in 43 children (mean age 7.1 years (3.6 to 12.0)) with fractures of the shaft of the femur. We reviewed their demographic data, mechanism of injury, associated injuries, the type and location of the fractures, the nail–canal diameter (NCD) ratios and femoral overgrowth at a mean follow-up of 40.7 months (25.2 to 92.7). At that time, the children were divided into two groups, those with femoral overgrowth of < 1 cm (Group 1), and those with overgrowth of ≥ 1 cm (Group 2). The mean femoral overgrowth of all patients was 0.6 cm at final follow-up. Overgrowth of ≥ 1 cm was noted in 11 children (25.6%). The NCD ratio was significantly lower in Group 2 than in Group 1, with an odds ratio of 30.0 (p = 0.003).

We believe that a low NCD ratio is an indicator of an unstable configuration with flexible intramedullary nailing, and have identified an association between a low NCD ratio and femoral overgrowth resulting in leg-length discrepancy after flexible intramedullary nailing in paediatric femoral shaft fractures.

Cite this article: Bone Joint J 2013;95-B:254–8.

The outcome of 219 revision total hip arthroplasties (THAs) in 98 male and 121 female patients, using 137 long length and 82 standard length cemented collarless double-taper femoral stems in 211 patients, with a mean age of 72 years (30 to 90) and mean follow-up of six years (two to 18) have been described previously. We have extended the follow-up to a mean of 13 years (8 to 20) in this cohort of patients in which the pre-operative bone deficiency Paprosky grading was IIIA or worse in 79% and 73% of femurs with long and standard stems, respectively.

For the long stem revision group, survival to re-revision for aseptic loosening at 14 years was 97% (95% confidence interval (CI) 91 to 100) and in patients aged > 70 years, survival was 100%. Two patients (two revisions) were lost to follow-up and 86 patients with 88 revisions had died. Worst-case analysis for survival to re-revision for aseptic loosening at 14 years was 95% (95% CI 89 to 100) and 99% (95% CI 96 to 100) for patients aged > 70 years. One additional long stem was classified as loose radiographically but not revised.

For the standard stem revision group, survival to re-revision for aseptic loosening at 14 years was 91% (95% CI 83 to 99). No patients were lost to follow-up and 49 patients with 51 hips had died. No additional stems were classified as loose radiographically.

Femoral revision using a cemented collarless double-taper stem, particularly with a long length stem, and in patients aged > 70 years, continues to yield excellent results up to 20 years post-operatively, including in hips with considerable femoral metaphyseal bone loss.

Cite this article: Bone Joint J 2015;97-B:1038–45.

Femoroacetabular impingement causes groin pain and decreased athletic performance in active adults. This bony conflict may result in femoroacetabular subluxation if of sufficient magnitude.

The ligamentum teres has recently been reported to be capable of withstanding tensile loads similar to that of the anterior cruciate ligament, and patents with early subluxation of the hip may become dependent on the secondary restraint that is potentially provided by the ligamentum teres. Rupture of the ligamentum may thus cause symptomatic hip instability during athletic activities.

An arthroscopic reconstruction of the ligamentum teres using iliotibial band autograft was performed in an attempt to restore this static stabiliser in a series of four such patients. Early clinical results have been promising. The indications, technique and early outcomes of this procedure are discussed.

The results of the treatment of 31 open femoral fractures (29 patients) with significant bone loss in a single trauma unit were reviewed. A protocol of early soft-tissue and bony debridement was followed by skeletal stabilisation using a locked intramedullary nail or a dynamic condylar plate for diaphyseal and metaphyseal fractures respectively. Soft-tissue closure was obtained within 48 hours then followed, if required, by elective bone grafting with or without exchange nailing.

The mean time to union was 51 weeks (20 to 156). The time to union and functional outcome were largely dependent upon the location and extent of the bone loss. It was achieved more rapidly in fractures with wedge defects than in those with segmental bone loss. Fractures with metaphyseal defects healed more rapidly than those of comparable size in the diaphysis. Complications were more common in fractures with greater bone loss, and included stiffness of the knee, malunion and limb-length discrepancy.

Based on our findings, we have produced an algorithm for the treatment of these injuries. We conclude that satisfactory results can be achieved in most femoral fractures with bone loss using initial debridement and skeletal stabilisation to maintain length, with further procedures as required.

Elastic stable intramedullary nailing (ESIN) is generally acknowledged to be the treatment of choice for displaced diaphyseal femoral fractures in children over the age of three years, although complication rates of up to 50% are described. Pre-bending the nails is recommended, but there are no published data to support this. Using synthetic bones and a standardised simulated fracture, we performed biomechanical testing to determine the influence on the stability of the fracture of pre-bending the nails before implantation. Standard ESIN was performed on 24 synthetic femoral models with a spiral fracture. In eight cases the nails were inserted without any pre-bending, in a further eight cases they were pre-bent to 30° and in the last group of eight cases they were pre-bent to 60°. Mechanical testing revealed that pre-bending to 60° produced a significant increase in the stiffness or stability of the fracture. Pre-bending to 60° showed a significant positive influence on the stiffness compared with unbent nails. Pre-bending to 30° improved stiffness only slightly.

These findings validate the recommendations for pre-bending, but the degree of pre-bend should exceed 30°. Adopting higher degrees of pre-bending should improve stability in spiral fractures and reduce the complications of varus deformity and shortening.

Flexible intramedullary nailing is gaining popularity as an effective method of treating long-bone fractures in children.

We retrospectively reviewed the records and radiographs of 56 unstable fractures of the tibia in 54 children treated between March 1997 and May 2005. All were followed up for at least two months after the removal of the nails.

Of the 56 tibial fractures, 13 were open. There were no nonunions. The mean time to clinical and radiological union was ten weeks. Complications included residual angulation of the tibia, leg-length discrepancy, deep infection and failures of fixation. All achieved an excellent functional outcome.

We conclude that flexible intramedullary fixation is an easy and effective method of management of both open and closed unstable fractures of the tibia in children.

This review considers the surgical treatment of displaced fractures involving the knee in elderly, osteoporotic patients. The goals of treatment include pain control, early mobilisation, avoidance of complications and minimising the need for further surgery. Open reduction and internal fixation (ORIF) frequently results in loss of reduction, which can result in post-traumatic arthritis and the occasional conversion to total knee replacement (TKR). TKR after failed internal fixation is challenging, with modest functional outcomes and high complication rates. TKR undertaken as treatment of the initial fracture has better results to late TKR, but does not match the outcome of primary TKR without complications. Given the relatively infrequent need for late TKR following failed fixation, ORIF is the preferred management for most cases. Early TKR can be considered for those patients with pre-existing arthritis, bicondylar femoral fractures, those who would be unable to comply with weight-bearing restrictions, or where a single definitive procedure is required.

Advances in the design of the components for total ankle replacement have led to a resurgence of interest in this procedure.

Between January 1999 and December 2004, 16 patients with a failed total ankle replacement were referred to our unit. In the presence of infection, a two-stage salvage procedure was planned. The first involved the removal of the components and the insertion of a cement spacer. Definitive treatment options included hindfoot fusion with a circular frame or amputation. When there was no infection, a one-stage salvage procedure was planned. Options included hindfoot fusion with an intramedullary nail or revision total ankle replacement. When there was suspicion of infection, a percutaneous biopsy was performed. The patients were followed up for a minimum of 12 months.

Of the 16 patients, 14 had aseptic loosening, five of whom underwent a revision total ankle replacement and nine a hindfoot fusion. Of the two with infection, one underwent fusion and the other a below-knee amputation. There were no cases of wound breakdown, nonunion or malunion.

Management of the failed total ankle replacement should be performed by experienced surgeons and ideally in units where multidisciplinary support is available. Currently, a hindfoot fusion appears to be preferable to a revision total ankle replacement.

It is becoming increasingly common for a patient to have ipsilateral hip and knee replacements. The inter-prosthetic (IP) distance, the distance between the tips of hip and knee prostheses, has been thought to be associated with an increased risk of IP fracture. Small gap distances are generally assumed to act as stress risers, although there is no real biomechanical evidence to support this.

The purpose of this study was to evaluate the influence of IP distance, cortical thickness and bone mineral density on the likelihood of an IP femoral fracture.

A total of 18 human femur specimens were randomised into three groups by bone density and cortical thickness. For each group, a defined IP distance of 35 mm, 80 mm or 160 mm was created by choosing the appropriate lengths of component. The maximum fracture strength was determined using a four-point bending test.

The fracture force of all three groups was similar (p = 0.498). There was a highly significant correlation between the cortical area and the fracture strength (r = 0.804, p <  0.001), whereas bone density showed no influence.

This study suggests that the IP distance has little influence on fracture strength in IP femoral fractures: the thickness of the cortex seems to be the decisive factor.

Cite this article: Bone Joint J 2014;96-B:1378–84.

We report the results of intramedullary leg lengthening conducted between 2002 and 2009 using the Intramedullary Skeletal Kinetic Distractor in 69 unilateral lengthenings involving 58 femora and 11 tibiae. We identified difficulties that occurred during the treatment and assessed whether they were specifically due to the implant or independent of it. Paley’s classification for evaluating problems, obstacles and complications with external fixators was adopted, and implant-specific difficulties were continuously noted. There were seven failures requiring premature removal of the device, in four due to nail breakage and three for other reasons, and five unsuccessful outcomes after completion of the lengthening. In all, 116 difficulties were noted in 45 patients, with only 24 having problem-free courses. In addition to the difficulties arising from the use of external fixators, there were almost the same number again of implant-specific difficulties.

Nevertheless, successful femoral lengthening was achieved in 52 of the 58 patients (90%). However, successful tibial lengthening was only achieved in five of 11 patients (45%).

Antegrade intramedullary nailing of fractures of the shaft of the humerus is reported to cause impairment of the shoulder joint. We have reviewed 33 patients with such fractures to assess how many had injuries to the ipsilateral shoulder. All had an MR scan of the shoulder within 11 days of injury. The unaffected shoulder was also scanned as a control. There was evidence of abnormality in 21 of the shoulders (63.6%) on the injured side; ten had bursitis of the subacromial space, five evidence of a partial tear of the rotator cuff, one a complete rupture of the supraspinatus tendon, four inflammatory changes in the acromioclavicular joint and one a fracture of the coracoid process. These injuries may contribute to pain and dysfunction of the shoulder following treatment, and their presence indicates that antegrade nailing is only partly, if at all, responsible for these symptoms.

The April 2014 Foot & Ankle Roundup³⁶⁰ looks at: Hawkins fractures revisited; arthrodesis compared with ankle replacement in osteoarthritis; mobile bearing ankle replacement successful in the longer-term; osteolysis is an increasing worry in ankle replacement; ankle synostosis post-fracture is not important; radiofrequency ablation for plantar fasciitis; and the right approach for tibiotalocalcaneal fusion.

In this study we evaluated the results of midtarsal release and open reduction for the treatment of children with convex congenital foot (CCF) (vertical talus) and compared them with the published results of peritalar release. Between 1977 and 2009, a total of 22 children (31 feet) underwent this procedure. In 15 children (48%) the CCF was isolated and in the remainder it was not (seven with arthrogryposis, two with spinal dysraphism, one with a polymalformative syndrome and six with an undefined neurological disorder).

Pre-operatively, the mean tibiotalar angle was 150.2° (106° to 175°) and the mean calcaneal pitch angle was -19.3° (-72° to 4°). The procedure included talonavicular and calcaneocuboid joint capsulotomies, lengthening of tendons of tibialis anterior and the extensors of the toes, allowing reduction of the midtarsal joints. Lengthening of the Achilles tendon was necessary in 23 feet (74%).

The mean follow-up was 11 years (2 to 21). The results, as assessed by the Adelaar score, were good in 24 feet (77.4%), fair in six (19.3%) and poor in one foot (3.3%), with no difference between those with isolated CCF and those without. The mean American Orthopaedic Foot and Ankle Society midfoot score was 89.9 (54 to 100) and 77.8 (36 to 93) for those with isolated CCF and those without, respectively. At the final follow-up, the mean tibiotalar (120°; 90 to 152) and calcaneal pitch angles (4°; -13 to 22) had improved significantly (p < 0.0001). Dislocation of the talonavicular and calcaneocuboid joints was completely reduced in 22 (70.9%) and 29 (93.6%) of feet, respectively. Three children (five feet) underwent further surgery at a mean of 8.5 years post-operatively, three with pes planovalgus and two in whom the deformity had been undercorrected. No child developed avascular necrosis of the talus.

Midtarsal joint release and open reduction is a satisfactory procedure, which may provide better results than peritalar release. Complications include the development of pes planovalgus and persistent dorsal subluxation of the talonavicular joint.

Cite this article: Bone Joint J 2014;96-B:837–44.

The mechanical performance of the cement-in-cement interface in revision surgery has not been fully investigated. The quantitative effect posed by interstitial fluids and roughening of the primary mantle remains unclear. We have analysed the strength of the bilaminar cement-bone interface after exposure of the surface of the primary mantle to roughening and fluid interference. The end surfaces of cylindrical blocks of cement were machined smooth (Ra = 200 nm) or rough (Ra = 5 μm) and exposed to either different volumes of water and carboxymethylcellulose (a bone-marrow equivalent) or left dry. Secondary blocks were cast against the modelled surface. Monoblocks of cement were used as a control group. The porosity of the samples was investigated using micro-CT. Samples were exposed to a single shearing force to failure.

The mean failure load of the monoblock control was 5.63 kN (95% confidence interval (CI) 5.17 to 6.08) with an estimated shear strength of 36 MPa. When small volumes of any fluid or large volumes were used, the respective values fell between 4.66 kN and 4.84 kN with no significant difference irrespective of roughening (p > 0.05). Large volumes of carboxymethylcellulose significantly weakened the interface. Roughening in this group significantly increased the strength with failure loads of 2.80 kN (95% CI 2.37 to 3.21) compared with 0.86 kN (95% CI 0.43 to 1.27) in the smooth variant. Roughening of the primary mantle may not therefore be as crucial as has been previously thought in clinically relevant circumstances.

Surface hip replacement (SHR) is generally used in younger, active patients as an alternative conventional total hip replacement in part because of the ability to preserve femoral bone. This major benefit of surface replacement will only hold true if revision procedures of SHRs are found to provide good clinical results.

A retrospective review of SHR revisions between 2007 and 2012 was presented, and the type of revision and aetiologies were recorded. There were 55 SHR revisions, of which 27 were in women. At a mean follow-up of 2.3 years (0.72 to 6.4), the mean post-operative Harris hip score (HHS) was 94.8 (66 to 100). Overall 23 were revised for mechanical reasons, nine for impingement, 13 for metallosis, nine for unexplained pain and one for sepsis. Of the type of revision surgery performed, 14 were femoral-only revisions; four were acetabular-only revisions, and 37 were complete revisions.

We did not find that clinical scores were significantly different between gender or different types of revisions. However, the mean post-operative HHS was significantly lower in patients revised for unexplained pain compared with patients revised for mechanical reasons (86.9 (66 to 100) versus 99 (96 to 100); p = 0.029). There were two re-revisions for infection in the entire cohort.

Based on the overall clinical results, we believe that revision of SHR can have good or excellent results and warrants a continued use of the procedure in selected patients. Close monitoring of these patients facilitates early intervention, as we believe that tissue damage may be related to the duration of an ongoing problem. There should be a low threshold to revise a surface replacement if there is component malposition, rising metal ion levels, or evidence of soft-tissue abnormalities.

Cite this article: Bone Joint J 2013;95-B, Supple A:88–91.

Although the use of constrained cemented arthroplasty to treat distal femoral fractures in elderly patients has some practical advantages over the use of techniques of fixation, concerns as to a high rate of loosening after implantation of these prostheses has raised doubts about their use. We evaluated the results of hinged total knee replacement in the treatment of 54 fractures in 52 patients with a mean age of 82 years (55 to 98), who were socially dependent and poorly mobile.

Within the first year after implantation 22 of the 54 patients had died, six had undergone a further operation and two required a revision of the prosthesis. The subsequent rate of further surgery and revision was low.

A constrained knee prosthesis offers a useful alternative treatment to internal fixation in selected elderly patients with these fractures, and has a high probability of surviving as long as the patient into whom it has been implanted.