The aim of this study was to investigate the
possible benefit of large-head metal-on-metal bearing on a stem
for primary hip replacement compared with a 28 mm diameter conventional
metal-on-polyethylene bearing in a prospective randomised controlled
trial. We investigated cemented stem behaviour between these two
different bearings using Einzel-Bild-Röntgen-Analyse, clinical and
patient reported measures (Harris hip score, Western Ontario and
McMaster Universities osteoarthritis index, Short Form-36 and satisfaction)
and whole blood metal ion levels at two years. A power study indicated
that 50 hips were needed in each group to detect subsidence of >
5 mm at two years with a
p-value of <
0.05. Significant improvement (p <
0.001) was found in the mean
clinical and patient reported outcomes at two years for both groups.
Comparison of outcomes between the groups at two years showed no
statistically significant difference for mean stem migration, clinical
and patient reported outcomes; except overall patient satisfaction which
was higher for metal-on-metal group (p = 0.05). Metal ion levels
were raised above the Medicines and Healthcare products Regulatory
Agency advised safety level (7 µg per litre) in 20% of the metal-on-metal
group and in one patient in metal-on-polyethylene group (who had
a metal-on-metal implant on the contralateral side). Two patients
in the metal-on-metal group were revised, one for pseudotumour and
one for peri-prosthetic fracture. Use of large modular heads is associated with a risk of raised
whole blood metal ion levels despite using a proven bearing from
resurfacing. The head-neck junction or excess stem micromotion are
possibly the weak links warranting further research.
It has been suggested that extracorporeal shockwave
therapy is a safe and effective treatment for pain relief from recalcitrant
plantar fasciopathy (PF). However, the changes in gait and associated
biomechanical parameters have not been well characterised. We recruited
12 female patients with recalcitrant PF who had a mean age of 59
years (50 to 70) and mean body mass index of 25 kg/m2 (22
to 30). The patients reported a mean duration of symptoms of 9.3
months (6 to 15). Shockwave therapy consisting of 1500 impulses
(energy flux density 0.26 mJ/mm2) was applied for three
sessions, each three weeks apart. A pain visual analogue scale (VAS)
rating, plantar pressure assessment and motion analysis were carried
out before and nine weeks after first shock wave therapy. It was demonstrated
that patients increased their walking velocity and cadence as well
indicating a decrease in pain after shockwave therapy. In the symptomatic
foot, the peak contact pressure over the forefoot increased and
the contact area over the digits decreased. The total foot impulse
also decreased as did stance duration. The duration the centre of
pressure remained in the hindfoot increased in the symptomatic foot
after shockwave therapy. The differences in centre of pressure trajectory
at baseline decreased at final follow-up. In conclusion, shockwave
therapy not only decreased the pain VAS rating but also improved
the gait parameters of the symptomatic foot in PF patients. Cite this article:
The timing of total hip replacement (THR) in
patients with active tuberculosis (TB) of the hip is controversial, because
of the potential risk of reactivation of infection. There is little
information about the outcome of THR in these patients. We conducted
a systematic review of published studies that evaluated the outcome
of THR in patients with active TB of the hip. A review of multiple
databases referenced articles published between 1950 and 2012. A
total of six articles were identified, comprising 65 patients. TB
was confirmed histologically in all patients. The mean follow-up
was 53.2 months (24 to 108). Antituberculosis treatment continued
post-operatively for between six and 15 months, after debridement
and THR. One non-compliant patient had reactivation of infection.
At the final follow-up the mean Harris hip score was 91.7 (56 to
98). We conclude that THR in patients with active TB of the hip
is a safe procedure, providing symptomatic relief and functional
improvement if undertaken in association with extensive debridement
and appropriate antituberculosis treatment. Cite this article:
Orthopaedic surgeons have accepted various radiological
signs to be representative of acetabular retroversion, which is
the main characteristic of focal over-coverage in patients with
femoroacetabular impingement (FAI). Using a validated method for
radiological analysis, we assessed the relevance of these signs
to predict intra-articular lesions in 93 patients undergoing surgery
for FAI. A logistic regression model to predict chondral damage
showed that an acetabular retroversion index (ARI) >
20%, a derivative
of the well-known cross-over sign, was an independent predictor
(p = 0.036). However, ARI was less significant than the Tönnis classification
(p = 0.019) and age (p = 0.031) in the same model. ARI was unable
to discriminate between grades of chondral lesions, while the type
of cam lesion (p = 0.004) and age (p = 0.047) were able to. Other
widely recognised signs of acetabular retroversion, such as the
ischial spine sign, the posterior wall sign or the cross-over sign
were irrelevant according to our analysis. Regardless of its secondary
predictive role, an ARI >
20% appears to be the most clinically
relevant radiological sign of acetabular retroversion in symptomatic
patients with FAI. Cite this article:
We report our early experience with a new peri-acetabular reconstruction endoprosthesis used for pelvic reconstruction after tumour resection. The outcome of 21 patients who underwent limb salvage following type II pelvic resection and reconstruction using the peri-acetabular reconstruction prosthesis between 2000 and 2006 was retrospectively reviewed. This prosthesis was designed to use the remaining part of the ilium to support a horizontally placed acetabular component secured with internal fixation and bone cement. Into this device a constrained acetabular liner is positioned which is articulates with a conventional femoral component to which a modular extension and modular head are attached. The mean follow-up was 20.5 months (1 to 77). The most common complications were deep infection, superficial wound infections, and dislocation. The mean musculoskeletal tumor society functional outcome score for the survivors was 20.1(11 to 27). We recommend the use of the peri-acetabular reconstruction prosthesis for reconstruction of large defects after type II pelvic resection, as this design has a greater inherent stability over other available prostheses.
Rupture of an aneurysm of the common iliac artery is a rare cause of pain in the hip. We describe an elderly hypertensive patient with an aneurysmal rupture of the left common iliac artery who presented with unilateral hip pain masquerading as septic arthritis.
We have developed a novel method of calculating the radiological magnification of the hip using two separate radio-opaque markers. We recruited 74 patients undergoing radiological assessment following total hip replacement. Both the new double marker and a conventional single marker were used by the radiographer at the time of x-ray. The predicted magnification according to each marker was calculated, as was the true radiological magnification of the components. The correlation between true and predicted magnification was good using the double marker (r = 0.90, n = 74, p <
0.001), but only moderate for the single marker (r = 0.50, n = 63, p <
0.001). The median error was significantly less for the double marker than for the single (1.1% The double marker method appears to be superior to the single marker method when used in the clinical environment.
We present the case of a young male patient with inferior dislocation of the hip and postulate a possible mechanism for this extremely rare injury.
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.
We investigated the eventual diagnosis in patients referred to a tertiary centre with a possible diagnosis of a primary bone malignancy. We reviewed our database from between 1986 and 2010, during which time 5922 patients referred with a suspicious bone lesion had a confirmed diagnosis. This included bone sarcoma in 2205 patients (37%), benign bone tumour in 1309 (22%), orthopaedic conditions in 992 (17%), metastatic disease in 533 (9%), infection in 289 (5%) and haematological disease in 303 (5%). There was a similar frequency of all diagnoses at different ages except for metastatic disease. Only 0.6% of patients (17 of 2913) under the age of 35 years had metastatic disease compared with 17.1% (516 of 3009) of those over 35 years (p <
0.0001). Of the 17 patients under 35 years with metastatic disease, only four presented with an isolated lesion, had no past history of cancer and were systematically well. Patients under the age of 35 years should have suitable focal imaging (plain radiography, CT or MRI) and simple systemic studies (blood tests and chest radiography). Reduction of the time to biopsy can be achieved by avoiding an unnecessary investigation for a primary tumour to rule out metastatic disease.
We retrospectively reviewed 40 hips in 36 patients who had undergone acetabular reconstruction using a titanium Kerboull-type acetabular reinforcement device with bone allografts between May 2001 and April 2006. Impacted bone allografts were used for the management of American Academy of Orthopaedic Surgeons Type II defects in 17 hips, and bulk bone allografts together with impacted allografts were used for the management of Type III defects in 23 hips. A total of five hips showed radiological failure at a mean follow-up of 6.7 years (4.5 to 9.3), two of which were infected. The mean pre-operative Merle d’Aubigné score was 10 (5 to 15) This clinical study indicates that revision total hip replacement using the Kerboull-type acetabular reinforcement device with bone allografts yielded satisfactory mid-term results.
We present the extended follow-up (≥ 20 years)
of a series of fully hydroxyapatite-coated femoral components used in
72 primary total hip replacements (THRs). Earlier results of this
cohort have been previously published. All procedures were performed
between 1986 and 1991. The series involved 45 women and 15 men with
12 bilateral procedures. Their mean age at the time of surgery was
60 years (46 to 80) and the mean duration of follow-up was 22.5
years (20 to 25). At final follow-up, the mean Merle d’Aubigné and
Postel hip scores were 5.5 (4.5 to 6), 3.8 (3.5 to 5) and 3.3 (3.0
to 5.0) for pain, mobility and function, respectively. Of the patients
92% were very satisfied at the time of final follow-up. There were seven revisions: six of the acetabular component for
aseptic loosening and one of both the stem and the acetabular component
for loosening due to deep infection. The survival of this prosthesis
at 22.5 years with revision for any reason as the endpoint was 91.7%
(95% confidence interval (CI) 84 to 99). Survival with aseptic loosening
of the stem as the endpoint was 100% (95% CI 90 to 100). This prosthesis provides pain relief in the long term. Survival
of this component is comparable to the best results for primary
THR with any means of fixation. Cite this article:
The April 2013 Children’s orthopaedics Roundup360 looks at: improving stress distribution in dysplastic hips; the dangers of fashion; the natural history of supracondylar fractures; ankles that perform well as knees; intra-articular hip pathology at osteotomy; the safe removal of flexible nails; supracondylar fracture fixation; and talipes.
The use of a navigation system in musculoskeletal tumour surgery enables the integration of pre-operative CT and MRI images to generate a precise three-dimensional anatomical model of the site and the extent of the tumour. We carried out six consecutive resections of musculoskeletal tumour in five patients using an existing commercial computer navigation system. There were three women and two men with a mean age of 41 years (24 to 47). Reconstruction was performed using a tumour prosthesis in three lesions and a vascularised fibular graft in one. No reconstruction was needed in two cases. The mean follow-up was 6.9 months (3.5 to 10). The mean duration of surgery was 28 minutes (13 to 50). Examination of the resected specimens showed clear margins in all the tumour lesions and a resection that was exactly as planned.
The effects of the method of fixation and interface conditions on the biomechanics of the femoral component of the Birmingham hip resurfacing arthroplasty were examined using a highly detailed three-dimensional computer model of the hip. Stresses and strains in the proximal femur were compared for the natural femur and for the femur resurfaced with the Birmingham hip resurfacing. A comparison of cemented
We have developed a CT-based navigation system using infrared light-emitting diode markers and an optical camera. We used this system to perform cementless total hip replacement using a ceramic-on-ceramic bearing couple in 53 patients (60 hips) between 1998 and 2001. We reviewed 52 patients (59 hips) at a mean of six years (5 to 8) postoperatively. The mid-term results of total hip replacement using navigation were compared with those of 91 patients (111 hips) who underwent this procedure using the same implants, during the same period, without navigation. There were no significant differences in age, gender, diagnosis, height, weight, body mass index, or pre-operative clinical score between the two groups. The operation time was significantly longer where navigation was used, but there was no significant difference in blood loss or navigation-related complications. With navigation, the acetabular components were placed within the safe zone defined by Lewinnek, while without, 31 of the 111 components were placed outside this zone. There was no significant difference in the Merle d’Aubigne and Postel hip score at the final follow-up. However, hips treated without navigation had a higher rate of dislocation. Revision was performed in two cases undertaken without navigation, one for aseptic acetabular loosening and one for fracture of a ceramic liner, both of which showed evidence of neck impingement on the liner. A further five cases undertaken without navigation showed erosion of the posterior aspect of the neck of the femoral component on the lateral radiographs. These seven impingement-related mechanical problems correlated with malorientation of the acetabular component. There were no such mechanical problems in the navigated group. We conclude that CT-based navigation increased the precision of orientation of the acetabular component and control of limb length in total hip replacement, without navigation-related complications. It also reduced the rate of dislocation and mechanical problems related to impingement.
Orientation of the native acetabular plane as defined by the transverse acetabular ligament (TAL) and the posterior labrum was measured intra-operatively using computer-assisted navigation in 39 hips. In order to assess the influence of alignment on impingement, the range of movement was calculated for that defined by the TAL and the posterior labrum and compared with a standard acetabular component position (abduction 45°/anteversion 15°). With respect to the registration of the plane defined by the TAL and the posterior labrum, there was moderate interobserver agreement (r = 0.64, p <
0.001) and intra-observer reproducibility (r = 0.73, p <
0.001). The mean acetabular component orientation achieved was abduction of 41° (32° to 51°) and anteversion of 18° (−1° to 36°). With respect to the Lewinnek safe zone (abduction 40° ±10°, anteversion 15° ±10°), 35 of the 39 acetabular components were within this zone. However, there was no improvement in the range of movement (p = 0.94) and no significant difference in impingement (p = 0.085). Alignment of the acetabular component with the TAL and the posterior labrum might reduce the variability of acetabular component placement in total hip replacement. However, there is only a moderate interobserver agreement and intra-observer reliability in the alignment of the acetabular component using the TAL and the posterior labrum. No reduction in impingement was found when the acetabular component was aligned with the TAL and the posterior labrum, compared with a standard acetabular component position.
Most children with spastic hemiplegia have high levels of function and independence but fixed deformities and gait abnormalities are common. The classification proposed by Winters et al is widely used to interpret hemiplegic gait patterns and plan intervention. However, this classification is based on sagittal kinematics and fails to consider important abnormalities in the transverse plane. Using three-dimensional gait analysis, we studied the incidence of transverse-plane deformity and gait abnormality in 17 children with group IV hemiplegia according to Winters et al before and after multilevel orthopaedic surgery. We found that internal rotation of the hip and pelvic retraction were consistent abnormalities of gait in group-IV hemiplegia. A programme of multilevel surgery resulted in predictable improvement in gait and posture, including pelvic retraction. In group IV hemiplegia pelvic retraction appeared in part to be a compensating mechanism to control foot progression in the presence of medial femoral torsion. Correction of this torsion can improve gait symmetry and function.
We undertook a randomised controlled trial to
compare bipolar hemiarthroplasty (HA) with a novel total hip replacement
(THR) comprising a polycarbonate–urethane (PCU) acetabular component
coupled with a large-diameter metal femoral head for the treatment
of displaced fractures of the femoral neck in elderly patients. Functional
outcome, assessed with the Harris hip score (HHS) at three months
and then annually after surgery, was the primary endpoint. Rates
of revision and complication were secondary endpoints. Based on a power analysis, 96 consecutive patients aged >
70
years were randomised to receive either HA (49) or a PCU-THR (47).
The mean follow-up was 30.1 months (23 to 50) and 28.6 months (22
to 52) for the HA and the PCU group, respectively. The HHS showed no statistically significant difference between
the groups at every follow-up. Higher pain was recorded in the PCU
group at one and two years’ follow-up
(p = 0.006 and p = 0.019, respectively). In the HA group no revision
was performed. In the PCU-THR group six patients underwent revision
and one patient is currently awaiting
re-operation. The three-year survival rate of the PCU-THR group
was 0.841 (95% confidence interval 0.680 to 0.926). Based on our findings we do not recommend the use of the PCU
acetabular component as part of the treatment of patients with fractures
of the femoral neck. Cite this article:
Many tumors metastasise to bone, therefore, pathologic
fracture and impending pathologic fractures are common reasons for
orthopedic consultation. Having effective treatment strategies is
important to avoid complications, and relieve pain and preserve
function. Thorough pre-operative evaluation is recommended for medical
optimization and to ensure that the lesion is in fact a metastasis
and not a primary bone malignancy. For impending fractures, various scoring
systems have been proposed to determine the risk of fracture, and
therefore the need for prophylactic stabilisation. Lower score lesions
can often be treated with radiation, while more problematic lesions
may require internal fixation. Intramedullary fixation is generally
preferred due to favorable biomechanics. Arthroplasty may be required
for lesions with massive bony destruction where internal fixation
attempts are likely to fail. Radiation may also be useful postoperatively
to minimise construct failure due to tumor progression.