Isolated liner exchange in revision total hip arthroplasty for the treatment of polyethylene wear is an increasingly common surgical procedure. Twenty-four hips underwent this procedure via the direct lateral approach and were prospectively followed clinically and radiographically. Accessible osteolytic lesions were curetted and bone grafted. At a mean follow-up of forty months, a significant clinical improvement was observed. One cup collapsed into an osteolytic lesion postoperatively; all other lesions regressed. No dislocations have occurred. Isolated liner exchange via the direct lateral approach may reduce dislocation rates while avoiding the morbidity associated with the removal of well-fixed components. The purpose of this study was to evaluate the clinical and radiographic results of isolated liner exchange in revision total hip arthroplasty (THA) for osteolysis and polyethylene wear via the direct lateral surgical approach. Retention of well-fixed implants avoids unnecessary bone loss at revision surgery. Previous studies report a significant dislocation rate with isolated liner exchange. Revision via the direct lateral surgical approach may reduce the dislocation rate in surgery for acetabular osteolysis. Twenty-four hips that underwent an isolated liner exchange revision procedure via the direct lateral approach were prospectively followed. Accessible osteolytic lesions were curetted and bone grafted. Harris Hip Score, WOMAC Index, and radiographic analysis were recorded. The area of osteolytic lesions was calculated using a computer imaging technique. At mean follow-up of forty months, all except one of the osteolytic lesions had regressed in size. Mean Harris Hip scores improved from sixty-nine to eighty-three and WOMAC indices improved from thirty-seven to twenty-four. No dislocations have occurred. One cup collapsed into an osteolytic lesion postoperatively, requiring an acetabular revision procedure. Isolated liner exchange is a promising technique that avoids the removal of well-fixed acetabular implants. The increased dislocation rate associated with revision THA may be reduced and osteolytic lesions may be debrided and bone grafted through the direct lateral approach. Isolated liner exchange via the direct lateral approach reduces the dislocation rate in THA. Retention of wellfixed implants and bone grafting is a procedure that preserves bone stock and addresses osteolytic lesions at revision surgery.
This paper presents radiological changes in femoral cortical allograft used to replace the disc in low back and leg pain syndromes. The technique originated with the use of patient’s own iliac crest but donor site pain and lack of rotational control with removal of the annulus resulted in a) femoral cortical allograft supplemented with b) posterior fixation, more recently of the trans-laminar screw variety. Experience with over 200 patients with femoral cortical allograft indicated that the rejection rate is virtually nil. Early changes include the loss of line between donor and host bone as early as three to four weeks after surgery. There is radiological evidence in some cases that radiological healing has taken place by four weeks. There is no radiological difference whether the patient’s own bone or allograft chips are used to pack the allograft cavity. At one year and beyond, the gap behind the allograft in the interbody space fills with host bone, thus avoiding any posterior migration of the allograft plug. There is some subsidence, over the first 12 months, into host bone. Attention to detail in surgical treatment of the end-plate is an important part of the technique. Axial views show dramatic changes up to 10 years after surgery. Gradual erosion of allograft by host bone, both at the external and internal diameter, occurs. Finally, there is the merest shell of donor bone identified, the rest clearly replaced by host bone. Unfortunately, biopsy samples to corelate with the radiological films are not available. Allograft bone in surgery was original with MacEwen of Glasgow (1880). Its use 30 years ago in scoliosis surgery was generally not successful. The interbody femoral cortical allograft succeeds by reason of the surgical principles involved: 1) Thorough clearance of all avascular (disc) tissue – thus, the provision of a thoroughly vascularised bed; 2) Rigid fixation (provided by the translaminar screw fixation). For reasons of cost, mechanics, biological behaviour and ease of shaping before insertion, femoral cortical allograft has provided an excellent long-term disc replacement.
The growth of non-myelinated pain fibres in other settings is regulated by the cytokine Nerve Growth Factor (NGF). In this study, we have investigated the production and distribution of NGF, or more particularly its active isoform – NGF-β, and its receptors, in diseased intervertebral discs in order to establish whether this cytokine might be responsible for the observed nerve ingrowth in this situation.
We treated 22 patients with type-two odontoid fractures in halothoracic vests for six to eight weeks followed by a Philadelphia collar for four weeks. Eighteen patients were reviewed by questionnaire and radiography at a mean of 40 months after injury. We assessed union, fracture position, the degree of permanent pain and stiffness, satisfaction with the treatment and the outcome. The overall union rate was 82%. Posterior malunion with residual posterior displacement or angulation was associated with a higher incidence of persisting pain. The position at union did not correlate with the residual cervical stiffness. Fractures failed to unite in four patients (18%) none of whom had late neurological sequelae, although they had more late pain. There were associations between the development of nonunion and an extension-type injury, age over 65 years and delay in diagnosis.