Correlation of MARS MRI findings with cup position, metal ion levels and function in metal-on-metal total hip arthroplasty.

INTRODUCTION: Metal-on-metal (MoM) total hip arthroplasties (THAs) have been linked with increased incidence of pseudotumours and revision rate. magnetic resonance imaging (MRI) is useful in diagnosing adverse reaction to metal debris (ARMD) disease but it is not known if MRI findings correlate with cup position. PATIENTS AND METHODS: From a cohort of 79 MoM THA, 34 MRI studies were available. MRI was classified according to Anderson classification. Mean follow-up was 7.1 years. Evaluation included cup position including margin of safety, measurement of metal ion levels and evaluation of function. RESULTS: 44% of patients had definite ARMD. We did not find any correlation between MRI stage and Co, Cr, margin of safety (MOS) or functional scores. However, patients with a margin of safety angle < 21° had more severe findings in MRI. CONCLUSIONS: Patients with MoM THA experience high degree of ARMD. In our study, the disease did not correlate with metal ion levels but correlated with cup position, evaluated with the MOS angle.

Enhancing biology and providing structural support for acetabular reconstruction in single-stage revision for infection.

BACKGROUND: Reconstruction of combined segmental and cavitary defects of the acetabulum is a challenge to the hip surgeon. One question regards the efficacy of reconstruction of acetabular defects using a combination of tantalum metal augments (TMAs) and impaction graft in single-stage revision for periprosthetic infection. MATERIALS AND METHODS: In the period between July 2009 and August 2014, 24 patients with combined segmental and cavitary acetabular defects and Paprosky classification grade IIB, IIC, and IIIA had hips reconstructed using the combination of TMAs and antibiotic-loaded impaction grafting. A similar group of 30 patients who received single-stage revision without metal augments were identified and taken as control. All patients received a polyethylene cemented cup and long cementless (Wagner SL) stem. Patients were prospectively evaluated using the modified Harris Hip Score (HHS) in addition to radiological evaluation at 3, 6, and 12 months then annually thereafter. RESULTS: At an average follow-up period of 4 years (range 2-7 years), all but one patient in the study group were free of infection, indicating a 96% success rate. This rate of eradicating infection was comparable to the 97% success rate in the control group. All metal augments were stable, and good incorporation of the impacted bone graft was observed. The HHS improved significantly from 27 preoperatively to 83 postoperatively (P < 0.001). CONCLUSION: Metal augments can convert massive acetabular defects to a more contained defect suitable for grafting. The combination of tantalum augments that provide strong structural support and antibiotic-loaded allograft is successful in the mid-term in single-stage revisions for infection. LEVEL OF EVIDENCE: Level IV (prospective case series).

Mid-term results of ReCap/Magnum/Taperloc metal-on-metal total hip arthroplasty with mean follow-up of 7.1 years.

INTRODUCTION: Despite enthusiasm for metal-on-metal bearings, disappointing short- to mid-term outcomes has all but halted the use of this bearing articulation. This review presents mid-term results for the ReCap Magnum total hip replacement. PATIENTS AND METHODS: This prospective study evaluated 79 ReCap/Magnum/Taperloc total hip replacements with mean follow-up of 7.1 (range 3.7-9.2) years. 43 were female and 36 male. Metal ions were measured and radiographic measurement included a 'margin of safety' angle to quantify risk of edge loading. When a clinical suspicion of adverse reaction to metal debris was present, patients had metal artefact reduction sequence MRI. Harris Hip Score and Oxford Hip Score evaluated functional outcome and SF-12 and EQ-5L-5D assessed quality of life at final follow-up. RESULTS: 7 hips were revised indicating 91.1% survivorship at 7.1 years. Postoperative Harris Hip Score and Oxford Hip Score significantly improved. Females and symptomatic patients predicted increased metal ions. Margin of safety correlated with postoperative Oxford Hip Score. Symptomatic hips and positive MRI showed reduced survivorship. CONCLUSIONS: Compared to more traditional bearings like metal or ceramic on polyethylene the overall outcome of this ReCap/Magnum/Taperloc study cohort is modest. It is felt that further failures will occur in this group therefore cautious interpretation of the results is justified given the potential for reduced survival outcomes.

A radiographic comparison of femoral offset after cemented and cementless total hip arthroplasty.

Restoring femoral offset during total hip arthroplasty is important. Femoral offset and leg lengths are inextricably linked by the caput-collum-diaphysis (CCD) angle of the implant being used. We investigate the restoration of offset and leg lengths using the radiographs of a consecutive series of patients following implantation with either a high CCD angled cementless, or an anatomical CCD angled cemented femoral component. Although our data suggests that we are able to restore femoral offset and leg lengths using either device, we recommend additional caution when using non-anatomical high CCD angled implants.

Resurfacing hip arthroplasty. A 3 to 5-year matched pair study of two different implant designs.

We compared the 3 to 5 year clinical and radiological results of two different hybrid metal-on-metal resurfacing hip arthroplasty designs in 28 patients who had undergone bilateral hip resurfacing with ReCap implants on one side and BHR implants on the other side. Both hips were compared in each patient, to specifically evaluate the bone response to the cemented femoral component. Post operative function was measured with the Harris Hip Score and University of California at Los Angeles (UCLA) Activity Score, and was excellent in these patients. Mean cup inclination was 43.3 degrees +/- 7 degrees (43.3 degrees +/- 7 degrees for the BHR and 43.4 +/- 6 degrees for the Recap). The inclination angle was greater than 45 degrees in 15 patients: 7 with a BHR, 8 with a Recap; eight patients showed inclination angles greater than 50 degrees (4 patients in each group). All acetabular monoblock cups were well fixed. One patient (1.8%) had radiographs showing bone changes of uncertain significance around the stem of the femoral component. Three percent had femoral bone resorption in the BHR hip and two percent showed bone resorption in the ReCap hip. There was no evidence of migration of the femoral components. The dual energy X-ray absorptiometry (DEXA) scans identified no real reduction in bone density in these resurfacing hip arthroplasties. None of these hips showed any other adverse features. The biological response showed no difference for the two different designs of resurfacing hip arthroplasties.

Use of irradiated bone graft for impaction grafting in acetabular revision surgery: a review of fifty consecutive cases.

Impaction bone grafting is a useful technique in the armament of a revision hip surgeon. Traditionally fresh frozen allograft has been used for this technique. However there are concerns about the transmission of viral proteins and prions through this form of allograft. As a result irradiated bone graft has been favoured in some centres. There is no long term series describing the results of impaction bone grafting using irradiated bone. This paper reviews a consecutive series of 50 cases of acetabular revision surgery performed between 1995 and 2001 and followed up over a mean period of 45 months. The preoperative bone defect was graded by the Paprosky classification. There were 2 cases of type 1a, 9 type 2a, 15 type 2b, 7 type 2c, 10 type 3a and 7 type 3b. All cases were followed up clinically and radiologically. Case notes were reviewed for primary prosthesis, operative details and reason for revision. The radiographs were evaluated for signs of bone incorporation, remodelling, loosening and migration of the acetabular component. There were 5 cases of aseptic loosening at the end of the follow up period. One patient had recurrent dislocation and was revised. 20 cases (40%) showed changes suggestive of bone incorporation, while only 3 cases (6%) showed remodelling. Clinically a good or excellent outcome with absence of pain was achieved in 35 patients (70%). The results suggested that acetabular impaction bone grafting using irradiated bone graft is comparable to fresh frozen allograft. The low percentage of remodelling remains a concern and warrants further studies.

Resurfacing hip replacement - An audit of activity in the United Kingdom 2002-2003.

The level of use of resurfacing hip replacement (RHR) and specific training undertaken was previously unknown in the United Kingdom. Consultant orthopaedic surgeons were audited by postal questionnaire regarding their RHR activity, training undertaken and evidence of specialisation in hip arthroplasty. RESULTS: 19% of surgeons had performed RHR in the previous 12 months. 33% of revision hip surgeons had performed RHR. The majority of consultants performed 6-10 cases per year. 73% performed less than 20 cases per year. For training, 30% had observed RHR surgery and 23% had attended a formal course. 7.8% of those performing RHR had neither been on a course nor observed surgery. Both British Hip Society membership and the completion of a hip fellowship were associated with the frequency of RHR . Those who had completed previous hip fellowship or were BHS members performed significantly more RHR. CONCLUSIONS: RHR is currently performed by specialists. The level of use is increasing rapidly and the standard of implantation needs to be safeguarded in order to ensure that the current successful short term results are maintained in the long term. Given the steep learning curve, the lack of long-term outcome and concerns regarding metal-on-metal bearings, we believe that the implant should continue to be used in accordance with NICE guidelines and that implantation should be performed by surgeons with a specialist interest in hip arthroplasty and specific training. (Hip International 2004; 14: 163-8).

A comparison of the reliability and validity of bone stock loss classification systems used for revision hip surgery.

Three femoral (Paprosky, American Academy of Orthopaedic Surgeons [AAOS], and Endo-Klinik) and 2 acetabular (Paprosky, AAOS) bone stock loss classification systems were evaluated for reliability. Four observers (2 consultants, 2 registrars) graded the bone loss in 25 patients using preoperative radiographs. Grading was repeated after a minimum of 2 weeks. Interobserver and intraobserver reliability was investigated. The kappa statistic was used to assess levels of agreement. Intraobserver agreement ranged from poor to good. Interobserver agreement ranged from fair to moderate. The validity of the Paprosky classification system was evaluated, comparing preoperative bone stock loss assessment with intraoperative findings. Agreement levels of moderate (femoral classification system) to good (acetabular classification system) were achieved. Bone stock loss classification systems are shown to be inconsistent and unreliable.

Orthopaedic surgery. Joint effort.

Hip replacement surgery is becoming increasingly specialised and evidence shows that, particularly in revision, surgery is best done by specialists. An audit of GPs suggests great variation in referral practice, with one-third prepared to refer to a 'generalist' orthopaedic surgeon. GPs need better communication with hospitals and knowledge of where specialists are available.

A new sign of inappropriate lower back pain.

The treatment of lower back pain constitutes a major problem for orthopaedic surgeons. Identifying the patients who have a non-organic component to their lower back pain is often difficult. Waddell et al. (Waddell G, McCulloch HA, Kummel E, Venner RM. Non-organic physical signs in low-back pain. Spine 1980; 5: 117-25) devised a set of five physical signs to assist in determining this. These signs are time consuming and can be difficult to interpret. We have developed a sign that is simple, quick and easy to perform. In a set of 94 patients, we have compared our sign with Waddell's signs. Our sign has a highly significant correlation with Waddell's signs (chi2 = 55.093, P < 0.001), and thus we would suggest it as an accurate alternative to Waddell's signs.

Artrite séptica subclínica do quadril no paciente idoso: um achado cirúrgico inesperado: relato de caso e revisäo de literatura / Subclinic septic arthritis of the hip in elderly patient: a unexpected perioperative finding

Relata-se um caso raro e subclínico de artrite séptica do quadril em paciente de 78 anos de idade, diagnosticado em achado inesperado intra-operatório de artroplastia total de quadril. A mais provável etiopatogenia é a via hematogênica originária de infecçao urinária ou intestinal ou metacrômica artroplástica. A artrite séptica no idoso (acima de 65 anos de idade) é rara. A incidência tem aumentado nos últimos 40 anos, apesar da proliferaçao de potentes antibióticos. É de difícil diagnóstico, como apresentado neste caso, e geralmente tem mau prognóstico.