Aims

In metal-on-metal (MoM) hip arthroplasties and resurfacings, mechanically induced corrosion can lead to elevated serum metal ions, a local inflammatory response, and formation of pseudotumours, ultimately requiring revision. The size and diametral clearance of anatomical (ADM) and modular (MDM) dual-mobility polyethylene bearings match those of Birmingham hip MoM components. If the acetabular component is satisfactorily positioned, well integrated into the bone, and has no surface damage, this presents the opportunity for revision with exchange of the metal head for ADM/MDM polyethylene bearings without removal of the acetabular component.

In metal-on-metal (MoM) hip replacements or resurfacings, mechanical induced corrosion can lead to a local inflammatory response, pseudo tumours and elevated serum metal ions, requiring revision surgery.

The size and diametral clearance of Anatomic (ADM) and Modular (MDM) Dual Mobility bearings matches that of certain MOM components. Presenting the opportunity for revision with exchange of the metal head for ADM/MDM bearings without removal of the acetabular component if it is well-fixed and appropriately positioned.

Between 2012 and 2020, across two centres, 94 patients underwent revision of a MoM hip replacement or resurfacing. The mean age was 65.5 (33–87) years. In 53 patients (56.4%), the acetabular component was retained, and dual mobility bearings were used (DM); in 41 (43.6%) the acetabulum was revised (AR). DM was only considered where the acetabular component was satisfactorily positioned and well-integrated into bone, with no surface damage. Patients underwent clinical and radiographic follow-up to at least one-year (mean 42.4 (12–96) months).

One (1.1%) patient died before one-year, for reasons unrelated to the surgery. In the DM group, two (3.8%) patients underwent further surgery; one (1.9%) for dislocation and one (1.9%) for infection. In the AR group, four (12.2%) underwent further procedures; two (4.9%) for loosening of the acetabular component and two (4.9%) following dislocations. There were no other dislocations in either group. In the DM group, operative time (68.4 v 101.5 mins, p<0.001), postoperative drop in haemoglobin (16.6 v 27.8 g/L, p<0.001), and length of stay (1.8 v 2.4 days, p<0.001) were significantly lower. There was a significant reduction in serum metal ions postoperatively in both groups (p<0.001 both Cobalt and Chromium) although there was no difference between groups for this reduction (p=0.674 Cobalt; p=0.186 Chromium).

In selected patients with MoM hip arthroplasty, where the acetabular component is well-fixed, in a satisfactory position and there is no surface damage, the metal head can be exchanged for ADM/MDM bearings with retention of the acetabular prosthesis. Presenting significant benefits through a less invasive procedure, and a low risk of complications, including dislocation.

Introduction. Single-stage resection and reimplantation for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) is of recent interest, yet outcomes may be skewed by selected populations with healthier patients and less virulent organisms. This study quantified the effectiveness of a contemporary, evidence-based and standardized two-stage treatment protocol in patients with THA PJI including chronically infected, poor hosts. Methods. Sixty-one consecutive two-stage resection and reimplantation THAs for PJI between 2011 and 2017 were retrospectively reviewed in a prospectively collected registry database. Patients were categorized with McPherson's Staging System and infection was defined by MSIS criteria. Contemporary standardized protocols were adhered to including implant resection and meticulous surgical debridement, six-week intravenous antibiotics with a high-dose antibiotic spacer, a two-week drug holiday, and laboratory assessment of infection eradication prior to reimplantation. Extended antibiotics after reimplantation were not routinely used. Successful treatment was defined as reimplantation with component retention at minimum two-year follow-up. Results. After exclusions for confounds, 43 of 47 patients had obtained minimum two-year follow-up (mean 50.9 months). 54% were male with an average BMI of 31 kg/m2. 56% were chronically infected poor hosts (Stage III-B/C). Three patients required repeat debridement and/or spacer exchange prior to final reimplantation. Treatment success rate was 95% at two-year follow-up. Success did not vary based on patient sex, age, BMI, or multi-organism PJI (p ≥ 0.117). There were no failures in the early postoperative PJI group (stage I), and both failures occurred in the late chronic PJI group (stage III). Conclusion. Our success rate with the two-stage procedure equals or exceeds that of single-stage treatment, even in an unselected cohort of chronically infected poor hosts. More rigorous scientific comparative studies are warranted prior to indiscriminate adoption of the single-stage treatment approach for PJI in THA

Uncemented component retention with polyethylene (PE) liner and femoral head exchange is commonly used to treat periprosthetic osteolysis. The purpose was to determine long-term implant survivorship, risk factors for aseptic failures, clinical outcomes, and complications following PE liner and head exchange. We identified 116 hips in 110 patients treated with PE liner and head exchange for osteolysis from 1993 to 2004. The mean age was 58, 64 were women, and mean follow-up was 11 years. Implant survivorship free from all-cause revisions was 91% at 5-years, 81% at 10-years, and 69% at 15-years. Reasons for re-revision included subsequent conventional PE wear and osteolysis in 7 (6%), aseptic acetabular loosening in 5 (4%), and instability in 5 hips (4%). Mean time to revision for aseptic acetabular loosening was 4 years (range 1 – 7 years). Risk factors for aseptic acetabular loosening included acetabular zones of pre-revision osteolysis, percentage of cup involvement, and size of osteolytic defects. Absolute risk of acetabular loosening was 23% for three zones of osteolysis (Relative Risk (RR) 12, p<0.01), 40% if osteolysis involved more than half the cup circumference (RR 14, p<0.01), and 21% for defects greater than 600 mm. 2. (RR 11, p<0.01). Harris hip scores improved from 77 to 87 (p<0.01). The most common complication was dislocation (16%). These data quantify risk of subsequent component loosening when well fixed, uncemented implants are retained during operations for osteolysis, and may inform operative decisions regarding shell retention versus revision

Aims

The prevalence of obesity is increasing substantially around the world. Elevated BMI increases the risk of complications following total hip arthroplasty (THA). We sought to evaluate trends in BMI and complication rates of obese patients undergoing primary THA over the last 30 years.

We have reviewed 202 consecutive primary hip replacements using a Freeman cemented femoral component after a mean period of follow-up of 64 months (23 to 113). There was only one revision for aseptic loosening. Retention of the femoral neck may act to reduce the torsional and shear forces at the implant-cement interface and may provide a seal against the migration of polyethylene-laden joint fluid in the potential joint space. The cemented Freeman femoral component with retention of the femoral neck was successful for up to nine years

Advances in the treatment of periprosthetic joint infections of the hip have once more pushed prosthesis preserving techniques into the limelight. At the same time, the common infecting organisms are evolving to become more resistant to conventional antimicrobial agents. Whilst the epidemiology of resistant staphylococci is changing, a number of recent reports have advocated the use of irrigation and debridement and one-stage revision for the treatment of periprosthetic joint infections due to resistant organisms. This review presents the available evidence for the treatment of periprosthetic joint infections of the hip, concentrating in particular on methicillin resistant staphylococci.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):60–5.

Aims

The aim of this study was to compare the survivorship and radiographic outcomes at ten-year follow-up of three prospective consecutive series of patients each of which received a different design of cementless femoral components for total hip arthroplasty (THA).

Osteolysis remains a common reason for revision after total hip arthroplasty (THA). For osteolysis associated with loose cups, revision is indicated. For osteolysis around a well-fixed cup, the decision is more controversial. The data available data support retention of the cupwith lesional treatment, working through screw holes and access channels for debridement and grafting. The choice of graft material to fill defects, if any, remains controversial. Several studies demonstrate good survivorship with cup retention strategies. Complete revision allows more complete debridement of the lesion and better graft fill, and allows implantation of a modern cup, typically with a full line of liners and bearing surfaces available. Additionally, revision allows fine tuning of the orientation of the cup, which may be advantageous for optimising hip stability. The author prefers to retain a well-fixed cup if it meets the following criteria: it is well-fixed to intra-operative testing, it is well-positioned, it is of sufficient size to allow insertion of a new liner with a reasonable head size, new liners are available, and the hip is stable to intra-operative trialing after liner insertion.

We hypothesised that the removal of the subchondral bone plate (SCBP) for cemented acetabular component fixation in total hip arthroplasty (THA) offers advantages over retention by improving the cement-bone interface, without jeopardising implant stability. We have previously published two-year follow-up data of a randomised controlled trial (RCT), in which 50 patients with primary osteoarthritis were randomised to either retention or removal of the SCBP. The mean age of the retention group (n = 25, 13 males) was 70.0 years (sd 6.8). The mean age in the removal group (n = 25, 16 males) was 70.3 years (sd 7.9). Now we have followed up the patients at six (retention group, n = 21; removal group, n = 20) and ten years (retention group: n = 17, removal group: n = 18), administering clinical outcome questionnaires and radiostereometric analysis (RSA), and determining the presence of radiolucent lines (RLLs) on conventional radiographs. RSA demonstrated similar translation and rotation patterns up to six years. Between six and ten years, proximal acetabular component migration and changes of inclination were larger in the retention group, although the mean differences did not reach statistical significance. Differences in migration were driven by two patients in the SCBP retention group with extensive migration versus none in the SCBP removal group. The significant difference (p < 0.001) in the development of radiolucent lines in the retention group, previously observed at two years, increased even further during the course of follow-up (p < 0.001). While recognising SCBP removal is a more demanding technique, we conclude that, wherever possible, the SCBP should be removed to improve the cement–bone interface in order to maximise acetabular component stability and longevity.

Cite this article: Bone Joint J 2015;97-B:35–44.