Paul Whittingham-Jones

Chromosomal Aberrations in the Peripheral Blood of Patients with Metal-on-Metal Hip Bearings

BACKGROUND Approximately one-third of patients undergoing joint replacement are under sixty years of age. Many of these patients may be exposed to wear debris from the orthopaedic implant for several decades. Clinical follow-up of this group of patients has been short compared with the lifetimes of the patients, and the long-term effects of this chronic exposure are unknown. METHODS By using cytogenetic biomarkers (twenty-four-color fluorescent in situ hybridization [FISH]), we analyzed the peripheral blood leukocytes for chromosomal aberrations in three groups of subjects: (1) six age and sex-matched control subjects who had no implant and did not smoke (control group), (2) five subjects in whom an implant with a metal-on-metal articulation had been in situ for an average of thirty-five years (metal-on-metal group), and (3) four subjects in whom a metal-on-metal implant had been revised to a metal-on-polyethylene articulation at an average of twenty-two years (revised group). RESULTS The number of chromosomal aberrations in the metal-on-metal group was greater than that in the control group. Specifically, the percentage of aneuploidy gain was three times greater (p = 0.01) in the metal-on-metal group. Structural aberrations were not seen in the control group, and this difference was highly significant (p = 0.003). Also, the number of chromosomal aberrations in the metal-on-metal group was greater than that in the revised group. Specifically, the percentage of structural aberrations was thirty-one-fold higher (p = 0.013). The percentage of aneuploidy gain in the metal-on-metal group was about twice that in the revised group, although this difference was not significant (p = 0.37). The percentage of aneuploidy gain in the revised group was about double that in the control group, although this difference was also not significant (p = 0.41). Translocations were seen only in subjects with a metal-on-metal articulation. CONCLUSIONS The clinical consequences of the chromosomal changes seen in this study are unknown, and it is unknown if the changes are present in other cells in the body. The results emphasize the need for additional investigations into the effect of chronic exposure to elevated levels of metal ions produced by orthopaedic implants.

Outcome of intralesional curettage for low-grade chondrosarcoma of long bones

BACKGROUND Different treatment strategies for low-grade chondrosarcomas are reported in the literature with variable outcomes. The aim of this study was to assess the oncological and functional outcomes associated with intralesional curettage and cementation of the lesion as a treatment strategy. PATIENTS AND METHODS We performed a retrospective review of 39 consecutive patients with intramedullary low-grade chondrosarcoma of long bones treated by intralesional curettage and cementation at our institution between 1999 and 2005. RESULTS There were 10 males and 29 females with a mean age of 55.5 years (32-82), and a mean follow-up of 5.1 years (3-8.7). Local recurrence occurred in two patients (5%) within the first two years following index surgery. Both were treated by re-curettage and cementation of the resultant defects. A second local recurrence developed a year later in one of these two patients, for which a further curettage followed by local liquid nitrogen treatment was performed. Overall, there were no cases of post-operative complications or metastases. The patients were assessed using the Musculoskeletal Tumour Society scoring system (MSTS) to determine limb function. The average score achieved was 94% (79-100%). CONCLUSION Intralesional curettage is an effective treatment strategy for low-grade intramedullary chondrosarcoma of long bones, with excellent oncological and functional results. Careful case selection with stringent clinical and radiographic follow-up is recommended.

Fracture of a ceramic component in total hip replacement

Fracture of a ceramic component in total hip replacement is a rare but potentially catastrophic complication. The incidence is likely to increase as the use of ceramics becomes more widespread. We describe such a case, which illustrates how inadequate initial management will lead to further morbidity and require additional surgery. We present the case as a warning that fracture of a ceramic component should be revised to another ceramic-on-ceramic articulation in order to minimise the risk of further catastrophic wear.

Immune Responses in Patients With Metal-on-Metal Hip Articulations: A Long-term Follow-up

Metal-on-metal (MoM) hip bearings are being inserted into ever-younger patients. The effects on the immune system of chronic exposure are unknown. We investigated the immune response of patients with MoM hip bearings. In patients with MoM implants, the expression of antigen-presenting cell (APC) surface molecules (CD86 and HLA-DR) was seen to be significantly higher (P < .05) than control group. High levels of APC surface molecules suggest an activated state and attempts to propagate an immune response. However, in the same group, the expression of T-cell markers (CD3 and CD28) was low, indicating a small T-cell population. This suggests, despite the activation of APCs, that T cells down-regulate immune responses in MoM articulations. Conversely, in metal-on-polyethylene articulations, expression of T-cell molecules was elevated and expression of APC molecules lowered.

Metal-On-Metal Bearings, Inflammatory Pseudotumours and Their Neurological Manifestations:

Metal-on-metal bearings have become more popular for hip arthroplasty in younger patients in the last 15 years. We present a review of the neurological consequences relating to such bearing surfaces illustrated by an appropriate case report. The mechanisms of increased metal ion production and pseudotumour formation are discussed. If unexplained neurology, hip/groin pain or a localised mass around the hip are present with a metal bearing hip then urgent referral to a specialist orthopaedic surgeon is warranted for consideration of exchange arthroplasty.

Osteoblastoma crossing the sacro-iliac joint

Osteoblastoma is a rare primary bone tumour which is well-described in the spine and sacrum. We report a case of histologically confirmed osteoblastoma in a 20-year-old male which crossed the sacroiliac joint. This has not previously been described to our knowledge. The imaging features of osteoblastoma and sacroiliac joint involvement by bone tumours are reviewed.

Custom-Made Cement-Linked Mega Prostheses: A Salvage Solution For Complex Periprosthetic Femoral Fractures

Periprosthetic femoral fractures with long stem implants, poor bone stock and loosening pose a considerable surgical challenge. We describe a reconstruction technique using a custom-made mega-prosthesis, cement-linked to the femoral stem of a well-fixed existing implant. Clinical and radiological outcomes were assessed at our tertiary referral centre. There were 15 patients with a periprosthetic femoral fracture: 5 proximal and 10 distal femoral arthroplasties linked to existing femoral stems. The survival rate was 93.3% at a mean follow-up of 5.3 years (0.5-19.3) with 1 revision. We present a salvage technique with good intermediate-term outcomes for highly selected patients with complex periprosthetic femoral fractures, as another option to conventional fixation methods. Specifically, it allows immediate weight bearing and avoids some of the morbidity of total femoral arthroplasty or amputation.

Metal-on-metal joint arthroplasty: Potential lifetime longevity

We have studied a historical group of patients who underwent metal-on-metal hip arthroplasty more than 30 years ago. Those retaining their original metal-on-metal articulation (average follow-up 33 years) had an average Harris Hip Score of 75 (range 53-93) and an average Musculoskeletal Tumour Outcome Score of 75 (range 63-90). Those that have been revised (at an average of 22 years) maintain good functional outcome. The original implant is still in situ in five of the 11 survivors (follow-up 26-38 years). Retrieval analysis using a Mitutoya form tracer and an electron microscope demonstrated the self-polishing capacity of the metal-on-metal articulation. The surface roughness (Ra) of the worn articulating surface (Ra 0.05 mm) was smoother than that of the original unworn surface (Ra 0.32 mm). We believe our case series highlights the potential longevity of metal-on-metal articulation.

The Bernese peri-acetabular osteotomy through a modified approach. A technical note

IntroductionA modification of the technique for performing the Bernese periacetabular osteotomy is described.Materials and methodsA medial approach to the Ischium and a subtle re-orientation of the pubic osteotomy are detailed.ConclusionSurgical morbidity is likely decreased with a concurrent cosmetic advantage without compromise to surgical correction or patient safety.

Total hip arthroplasty in teenagers: an alternative to hip arthrodesis

Debilitating arthritis in teenage patients is a complex problem with limited surgical options. Hip arthrodesis is unpopular amongst patients, and contemporary total hip arthroplasty (THA) may be a promising alternative. We report on the outcomes of THA in patients less than 20 years of age. All consecutive teenage patients undergoing THA at a tertiary referral centre were reviewed. Mean follow-up was 3.4 years (range 0.6–6.8) and 9 patients had at least 5 years follow-up. There were 51 THAs in 43 patients with a mean age of 17 years (range 12–19). The commonest indication was osteonecrosis (35 cases), mostly secondary to slipped upper femoral epiphysis (15 cases). Forty-six were uncemented and 5 were reverse hybrid THAs of which 7 were computer assisted design/manufacture (CADCAM) components. The commonest bearing surface used was ceramic on ceramic (40 cases). The survival rate was 96% and there were 2 complications. At latest follow-up, the mean Harris hip score was 90 (range 68–99) and UCLA activity score was 6 (range 4–9). Radiological analysis showed 2 patients with lucent lines around the acetabular component, but no signs of osteolysis or wear. We report good short to intermediate term survivorship and outcomes, and feel THA represents a valid alternative option to hip arthrodesis.