The December 2013 Children’s orthopaedics Roundup360 looks at: Long term-changes in hip morphology following osteotomy; Arthrogrypotic wrist contractures are surgically amenable; Paediatric femoral lengthening over a nail; Current management of paediatric supracondylar fractures; MRI perfusion index predictive of Perthes’ progression; Abduction bracing effective in residual acetabular deformity; Hurler syndrome in the spotlight; and the Pavlik works for femoral fractures too!
We prospectively evaluated the long-term outcome of 158 consecutive patients who underwent revision total hip replacement using uncemented computer-assisted design-computer-assisted manufacture femoral components. There were 97 men and 61 women. Their mean age was 63.1 years (34.6 to 85.9). The mean follow-up was 10.8 years (10 to 12). The mean Oxford, Harris and Western Ontario and McMaster hip scores improved from 41.1, 44.2 and 52.4 pre-operatively to 18.2, 89.3 and 12.3, respectively (p <
0.0001, for each). Six patients required further surgery. The overall survival of the femoral component was 97% (95% confidence interval 94.5 to 99.7). These results are comparable to those of previously published reports for revision total hip replacement using either cemented or uncemented components.
Down’s syndrome is associated with a number of
musculoskeletal abnormalities, some of which predispose patients
to early symptomatic arthritis of the hip. The purpose of the present
study was to review the general and hip-specific factors potentially
compromising total hip replacement (THR) in patients with Down’s
syndrome, as well as to summarise both the surgical techniques that
may anticipate the potential adverse impact of these factors and
the clinical results reported to date. A search of the literature
was performed, and the findings further informed by the authors’
clinical experience, as well as that of the hip replacement in Down
Syndrome study group. The general factors identified include a high
incidence of ligamentous laxity, as well as associated muscle hypotonia
and gait abnormalities. Hip-specific factors include: a high incidence
of hip dysplasia, as well as a number of other acetabular, femoral
and combined femoroacetabular anatomical variations. Four studies
encompassing 42 hips, which reported the clinical outcomes of THR
in patients with Down’s syndrome, were identified. All patients
were successfully treated with standard acetabular and femoral components.
The use of supplementary acetabular screw fixation to enhance component
stability was frequently reported. The use of constrained liners
to treat intra-operative instability occurred in eight hips. Survival
rates of between 81% and 100% at a mean follow-up of 105 months
(6 to 292) are encouraging. Overall, while THR in patients with
Down’s syndrome does present some unique challenges, the overall
clinical results are good, providing these patients with reliable
pain relief and good function. Cite this article:
We compared the clinical and radiological outcomes
of two cementless femoral stems in the treatment of patients with
a Garden III or IV fracture of the femoral neck. A total of 70 patients At final follow-up there were no statistically significant differences
between the short anatomical and the conventional stems with regard
to the mean Harris hip score (85.7 (66 to 100) Our study demonstrated that despite the poor bone quality in
these elderly patients with a fracture of the femoral neck, osseo-integration
was obtained in all hips in both groups. However, the incidence
of thigh pain, pulmonary microemboli and peri-prosthetic fracture
was significantly higher in the conventional stem group than in
the short stem group.
We present the 10- to 17-year results of 112 computer-assisted design computer-assisted manufacture femoral components. The total hip replacements were performed between 1992 and 1998 in 111 patients, comprising 53 men and 58 women. Their mean age was 46.2 years (24.6 to 62.2) with a mean follow-up of 13 years (10 to 17). The mean Harris Hip Score improved from 42.4 (7 to 99) to 90.3 (38 to 100), the mean Oxford Hip Score from 43.1 (12 to 59) to 18.2 (12 to 51) and the mean Western Ontario MacMasters University Osteoarthritis Index score from 57.0 (7 to 96) to 11.9 (0 to 85). There was one revision due to failure of the acetabular component but no failures of the femoral component. There were no revisions for aseptic loosening. The worst-case survival in this cohort of custom femoral components at 13.2 years follow-up was 98.2% (95% confidence interval 95 to 99). Overall survival of this series of total hip replacements was 97.3% (95% confidence interval 95 to 99). These results are comparable with the best medium- to long-term results for femoral components used in primary total hip replacement with any means of fixation.
Revision surgery of the hip was performed on 114 hips using an extensively porous-coated femoral component. Of these, 95 hips (94 patients) had a mean follow-up of 10.2 years (5 to 17). No cortical struts were used and the cortical index and the femoral cortical width were measured at different levels. There were two revisions for aseptic loosening. Survivorship at 12 years for all causes of failure was 96.9% (95% confidence interval 93.5 to 100) in the best-case scenario. Fibrous or unstable fixation was associated with major bone defects. The cortical index (p = 0.045) and the lateral cortical thickness (p = 0.008) decreased at the proximal level over time while the medial cortex increased (p = 0.001) at the proximal and distal levels. An increase in the proximal medial cortex was found in patients with an extended transtrochanteric osteotomy (p = 0.026) and in those with components shorter than 25 cm (p = 0.008). The use of the extensively porous-coated femoral component can provide a solution for difficult cases in revision surgery. Radiological bony ingrowth is common. Although without clinical relevance at the end of follow-up, the thickness of the medial femoral cortex often increased while that of the lateral cortex decreased. In cases in which a shorter component was used and in those undertaken using an extended trochanteric osteotomy, there was a greater increase in thickness of the femoral cortex over time.
One commonly used rat fracture model for bone and mineral research
is a closed mid-shaft femur fracture as described by Bonnarens in
1984. Initially, this model was believed to create very reproducible
fractures. However, there have been frequent reports of comminution
and varying rates of complication. Given the importance of precise
anticipation of those characteristics in laboratory research, we
aimed to precisely estimate the rate of comminution, its importance and
its effect on the amount of soft callus created. Furthermore, we
aimed to precisely report the rate of complications such as death
and infection. We tested a rat model of femoral fracture on 84 rats based on
Bonnarens’ original description. We used a proximal approach with
trochanterotomy to insert the pin, a drop tower to create the fracture
and a high-resolution fluoroscopic imager to detect the comminution.
We weighed the soft callus on day seven and compared the soft callus
parameters with the comminution status.Objectives
Methods
Recent guidance recommends the use of a well-proven
cemented femoral stem for hemiarthroplasty in the management of
fractures of the femoral neck, and the Exeter Trauma Stem (ETS)
has been suggested as an example of such an implant. The design
of this stem was based on the well-proven Exeter Total Hip Replacement
stem (ETHRS). This study assessed the surface finish of the ETS
in comparison with the ETHRS. Two ETSs and two ETHRSs were examined
using a profilometer with a precision of 1 nm and compared with
an explanted Exeter Matt stem. The mean roughness average (RA) of
the ETSs was approximately ten times higher than that of the ETHRSs (0.235 μm
(0.095 to 0.452) Cite this article:
We report a multicentre prospective consecutive
study assessing the long-term outcome of the proximally hydroxyapatite
(HA)-coated ABG II monobloc femoral component in a series of 1148
hips in 1053 patients with a mean age at surgery of 64.77 years
(22 to 80) at a mean follow-up of 10.84 years (10 to 15.25). At
latest follow-up, the mean total Harris hip score was 94.7 points
( Cite this article:
Using a modern cementing technique, we implanted 22 stereolithographic polymeric replicas of the Charnley-Kerboul stem in 11 pairs of human cadaver femora. On one side, the replicas were cemented line-to-line with the largest broach. On the other, one-size undersized replicas were used (radial difference, 0.89 mm CT analysis showed that the line-to-line stems without distal centralisers were at least as well aligned and centered as undersized stems with a centraliser, but were surrounded by less cement and presented more areas of thin (<
2 mm) or deficient (<
1 mm) cement. These areas were located predominantly at the corners and in the middle and distal thirds of the stem. Nevertheless, in line-to-line stems, penetration of cement into cancellous bone resulted in a mean thickness of cement of 3.1 mm ( When Charnley-Kerboul stems are cemented line-to-line, good clinical results are observed because cement-deficient areas are limited and are frequently supported by cortical bone.
Patient-specific cutting guides (PSCGs) are designed
to improve the accuracy of alignment of total knee replacement (TKR).
We compared the accuracy of limb alignment and component positioning
after TKR performed using PSCGs or conventional instrumentation.
A total of 80 patients were randomised to undergo TKR with either of
the different forms of instrumentation, and radiological outcomes
and peri-operative factors such as operating time were assessed.
No significant difference was observed between the groups in terms
of tibiofemoral angle or femoral component alignment. Although the
tibial component in the PSCGs group was measurably closer to neutral
alignment than in the conventional group, the size of the difference
was very small (89.8° ( Cite this article:
A total of 219 hips in 192 patients aged between
18 and 65 years were randomised to 28-mm metal-on-metal uncemented
total hip replacements (THRs, 107 hips) or hybrid hip resurfacing
(HR, 112 hips). At a mean follow-up of eight years (6.6 to 9.3)
there was no significant difference between the THR and HR groups
regarding rate of revision (4.0% (4 of 99) Cite this article:
Revision total hip arthroplasty (THA) is projected
to increase by 137% from the years 2005 to 2030. Reconstruction of
the femur with massive bone loss can be a formidable undertaking.
The goals of revision surgery are to create a stable construct,
preserve bone and soft tissues, augment deficient host bone, improve
function, provide a foundation for future surgery, and create a
biomechanically restored hip. Options for treatment of the compromised femur
include: resection arthroplasty, allograft prosthetic composite
(APC), proximal femoral replacement, cementless fixation with a
modular tapered fluted stem, and impaction grafting. The purpose
of this article is to review the treatment options along with their
associated outcomes in the more severe femoral defects (Paprosky types
IIIb and IV) in revision THA.
We describe 129 consecutive revision total hip replacements using a Charnley-Kerboull femoral component of standard length with impaction allografting. The mean follow-up was 8.2 years (2 to 16). Additionally, extramedullary reinforcement was performed using struts of cortical allograft in 49 hips and cerclage wires in 30. There was one intra-operative fracture of the femur but none later. Two femoral components subsided by 5 mm and 8 mm respectively, and were considered to be radiological failures. No further revision of a femoral component was required. The rate of survival of the femoral component at nine years, using radiological failure as the endpoint, was 98%. Our study showed that impaction grafting in association with a Charnley-Kerboull femoral component has a low rate of subsidence. Reconstruction of deficiencies of distal bone with struts of cortical allograft appeared to be an efficient way of preventing postoperative femoral fracture for up to 16 years.
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:
In this paper, we will consider the current role
of metal-on-metal bearings by looking at three subtypes of MoM hip
arthroplasty separately: Hip resurfacing, large head (>
36 mm) MoM
THA and MoM THA with traditional femoral head sizes.
The use of short stems has become more popular
with the increased interest in less invasive approaches for total hip
arthroplasty. The curved broaches and stem can be inserted along
a curved track to avoid the abductor attachments. Short stems have
the potential of being more bone conserving by allowing for higher
neck retention, maintenance of the medial greater trochanter, and
preferential stress transfer to the proximal femur. An initial experience with 500 new short stems (Fitmore, Zimmer
Orthopedics) stems used for total hip arthroplasty is reported.
No stems have been revised for aseptic loosening.
The Thompson hemiarthroplasty is a popular hip prosthesis. We present two case reports highlighting a significant alteration in the design of the implant which compromised the success of the operations. In recent years the manufacturing process of this prosthesis has changed, with a resultant increase in the volume of the stem of 10 ml. It is essential that manufacturers inform orthopaedic surgeons of any alteration in the design of the implant and supply compatible instrumentation to minimise surgical errors. Surgeons must remain vigilant when checking the compatibility of the trial and definitive prostheses.
The December 2012 Research Roundup360 looks at: whether the rheumatoid factor is just a ‘quick test’; osteonecrosis in smokers; pasteurisation effect on bone reconstruction; venous thromboembolism risk in rheumatoids; whether stem cells reverse age-related osteopenia; the effect of running on rat knees; rapid fracture healing in rats with ultrasound; magnetic stem cells; and the safety of surgery.
We have managed 27 patients (16 women and 11 men) with a mean age of 68.4 years (50 to 84), with failed total hip replacement and severe proximal femoral bone loss by revision using a distal fix/proximal wrap prosthesis. The mean follow-up was for 55.3 months (25 to 126). The mean number of previous operations was 2.2 (1 to 4). The mean Oxford hip score decreased from 46.2 (38 to 60) to 28.5 (17 to 42) (paired t-test, p <
0.001) and the mean Harris Hip score increased from 30.4 (3 to 57.7) to 71.7 (44 to 99.7) (paired t-test, p <
0.001). There were two dislocations, and in three patients we failed to eradicate previous infection. None required revision of the femoral stem. This technique allows instant distal fixation while promoting biological integration and restoration of bone stock. In the short term, the functional outcome is encouraging and the complication rates acceptable in this difficult group of patients.