Kerry Costi

Loosening of matt and polished cemented femoral stems

We have compared prospectively the incidence of loosening of 20 femoral stems with a matt surface with that of 20 polished stems of an otherwise identical tapered, non-modular design of Exeter hip replacement. The stems were inserted using the same technique at operation and radiographs showed no difference in the adequacy of the cement mantle or of fixation. All the patients were reviewed regularly and none was lost to follow-up. After a minimum follow-up of nine years, four matt but no polished stems had been revised for aseptic loosening. Polished stems subsided slightly within the cement mantle early, but did not loosen.

Effects of design changes on cemented tapered femoral stem fixation

The effects of matte finish and modularity on loosening of tapered stems using the same cementing technique were studied prospectively. In 80 patients, 82 cemented Exeter primary stems were implanted at total hip revision by one surgeon using the same surgical and cementing technique throughout the series. The polished stems behaved differently than the matte surfaced stems behaved. Polished stems subsided in the cement mantle an average of 1 mm at 2 years after implantation, but without subsequent loosening of stems at as long as 12 years after implantation. Matte surfaced stems with metal centralizers had a higher loosening rate, and loss of fixation at the prosthesis to cement interface was identified as an early sign of loosening of these stems. At a mean 6-year followup, there were no revisions nor was there radiographic evidence of loosening of the polished modular stems. It is concluded that matte finish results in increased loosening of tapered stems but the introduction of modularity did not.

Implant retrieval studies of the wear and loosening of prosthetic joints: a review

Joint replacement surgery is established as a cost-effective treatment for degenerative joint disorders, but periprosthetic bone loss and aseptic loosening of prostheses is the major surgical complication of this procedure. Early loosening is related to poor initial fixation and design. Late loosening, which is the major problem and the principal cause of failure of this procedure, is related to wear of the prosthetic components. From the retrieval and analysis of failed implants, hypotheses regarding the mechanism of wear-induced loosening and other causes for implant failure may be developed. The criteria and methods, which we have developed for undertaking analysis, and the potentially valuable information available from these analyses, are reviewed.

Progression of periacetabular osteolytic lesions.

BACKGROUND The development of three-dimensional computed tomography (CT) imaging techniques has enabled the detection, accurate measurement, and monitoring of periprosthetic osteolytic lesions. The aim of this study was to track the progression in size of osteolytic lesions and to determine those factors that are associated with the risk of progression. A secondary aim was to investigate whether progression in size of osteolytic lesions could be monitored with use of radiographs. METHODS We retrospectively determined, with use of sequential CT scans, the progression of periacetabular osteolysis over a period of as much as nine years in a cohort of twenty-six patients (thirty acetabular components) in whom the cementless acetabular component or components had been in place for longer than ten years at the time of the initial CT scan. High-resolution CT scans with metal-artifact suppression were used to determine the volume of osteolytic lesions. Progression in the size of osteolytic lesions per year was calculated as the change in the volume of osteolytic lesions between serial CT scans. Associations were determined between the progression in size of osteolytic lesions, osteolysis rate at the initial CT, patient age, sex, walking limitations, and activity level. Progression in size of osteolytic lesions as determined with use of CT was compared with that determined with use of radiographs. RESULTS Mean progression in the size of osteolytic lesions, as determined with use of CT, was 1.5 cm(3)/yr (range, 0 to 7.5 cm(3)/yr). The amount of osteolysis at the initial CT scan and patient activity were good predictors of osteolytic lesion progression. The strongest predictor of osteolytic lesion progression occurred when these two risk factors were combined (p = 0.0019). The value of radiographs was limited to monitoring of larger lesions identified by CT. CONCLUSIONS This is the first study to report on the progression of osteolysis adjacent to cementless acetabular components from medium to long-term follow-up. The data suggest that the osteolysis rate at the initial CT and patient activity can be useful factors in predicting the progression in size of periacetabular osteolytic lesions.

Validity and Reliability of the Paprosky Acetabular Defect Classification

BackgroundThe Paprosky acetabular defect classification is widely used but has not been appropriately validated. Reliability of the Paprosky system has not been evaluated in combination with standardized techniques of measurement and scoring.Questions/purposesThis study evaluated the reliability, teachability, and validity of the Paprosky acetabular defect classification.MethodsPreoperative radiographs from a random sample of 83 patients undergoing 85 acetabular revisions were classified by four observers, and their classifications were compared with quantitative intraoperative measurements. Teachability of the classification scheme was tested by dividing the four observers into two groups. The observers in Group 1 underwent three teaching sessions; those in Group 2 underwent one session and the influence of teaching on the accuracy of their classifications was ascertained.ResultsRadiographic evaluation showed statistically significant relationships with intraoperative measurements of anterior, medial, and superior acetabular defect sizes. Interobserver reliability improved substantially after teaching and did not improve without it. The weighted kappa coefficient went from 0.56 at Occasion 1 to 0.79 after three teaching sessions in Group 1 observers, and from 0.49 to 0.65 after one teaching session in Group 2 observers.ConclusionsThe Paprosky system is valid and shows good reliability when combined with standardized definitions of radiographic landmarks and a structured analysis.Level of EvidenceLevel II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Mentoring in complex surgery: minimising the learning curve complications from peri-acetabular osteotomy

PurposeThe aim of this study was to determine whether a complex surgical procedure such as peri-acetabular osteotomy could be safely learnt by using a programme involving mentoring by a distant expert. To determine this, we examined the incidence of intra-operative complications, the acetabulum correction achieved, the late incidence of re-operation and progressive degenerative arthritis.MethodsBetween 1992 and 2004, peri-acetabular osteotomy was performed in 26 hips in 23 patients. The median follow-up was ten (5–17) years. The median age of the patients at operation was 28 (14–41) years. Clinical outcomes were reported and radiographic results were determined by an independent expert.ResultsThere were no intra-articular osteotomies, sciatic nerve injuries, hingeing deformities or vascular injuries. There was one ischial nonunion. The lateral centre-edge angle improved from a median 4° pre-operatively to 25°. One revision osteotomy, one osteectomy and three total hip replacements were required, two for progression of osteoarthritis.ConclusionsThe programme of mentoring was successful in that there was a low incidence of the major intra-operative complications that are often reported during the learning curve period and the acetabular corrections achieved were similar to the originators.

Long-term survival and reason for revision of Wagner resurfacing hip arthroplasty.

The long-term survival of 270 Wagner resurfacing hip arthroplasties was determined. Two patients were lost to follow-up. Eleven hips remained unrevised at 15 to 22 years. Survival at 5, 10, and 16 years was 74%, 35%, and 17%, respectively. Survival in patients older than 55 years was better after 5 years than that for patients 55 years or younger (P = .0067). Femoral neck fracture occurred in 2% of the total cohort. Femoral component failure was an early and midterm complication. Acetabular component loosening was the most common reason for revision. The proportion of cases revised for acetabular component failure increased with time. These long-term data in this large series provide important historical results against which the relative benefits of contemporary designs may be evaluated.

Ultimate tensile strength of a Leeds–Keio/autograft ACL reconstruction utilizing PLLA tibial staple fixation

An ovine model of anterior cruciate ligament reconstruction was utilized to evaluate the biomechanical and histological response of a polylactic acid tibial fixation staple (Gunze Ltd., Japan/Zimmer, Japan). This was performed in a comparison with metallic staples, currently utilized for this procedure. The prosthesis consisted of autograft combined with a Leeds-Keio (L-K) ligament. Early post-operative mobilization was followed by retrieval of specimens at 6, 12 and 24 weeks post-reconstruction. Evaluation of the mechanical characteristics of the graft reconstructions (tensile strength) showed no significant differences (P>0.05) between the staple types for each time period. The histological response to the polylactic acid staple was minimal over the time period studied, with no adverse tissue reactions observed. The mode of reconstruction failure was observed to change with time (P<0.05) presumably as the graft characteristics alter. Overall the absorbable staples performed at a comparable level with the metallic staples within the scope of the study.

Advantages in Using Cemented Polished Tapered Stems When Performing Total Hip Arthroplasty in Very Young Patients

BACKGROUND The risk of revision following primary total hip arthroplasty (THA) is increased in young patients who undergo THA for pathologies other than primary osteoarthritis. We report the results of primary THA performed with cemented polished stems in patients aged 40 years and younger for pathologies other than primary osteoarthritis. METHODS We investigated 52 patients (65 hips) who underwent primary THA for secondary osteoarthritis with a cemented tapered polished stem between 1990 and 2007. Clinical and radiographic outcomes, available in 46 patients (57 hips), included the Harris Hip Scores, Societe Internationale de Chirurgie Orthopedique et de Traumatologie activity, patient satisfaction, stem survival and reoperations, and assessment of prosthesis-cement-bone radiolucencies, osteolysis, and femoral bone deficiencies. RESULTS Median patient age was 34 years (16-40) and follow-up was 14 years (mean 13, range 5-22). Stem survival to the endpoint revision for loosening was 100% and to the endpoint revision for any reason, excluding infection was 88% (95% confidence interval 78-98) at 16 years. No stem was revised for aseptic loosening. Nine stems were revised for other reasons. Radiographically, one stem was definitely loose at 16 years. The median patient Harris pain score improved from marked pain to no pain at latest follow-up. Patient activity level improved, albeit minimally, for 8 years after surgery. At latest follow-up, 98% of the patients remained satisfied with their surgery. CONCLUSION Primary THA with a cemented polished stem shows excellent results in young patients with pathology other than primary osteoarthritis. In addition, the stem design facilitates cement within cement exchange and therefore preservation of proximal femoral bone stock at revision surgery.

Revision total hip arthroplasty using cemented collarless double-taper femoral components at a mean follow-up of 13 years (8 to 20): an update

The outcome of 219 revision total hip arthroplasties (THAs) in 98 male and 121 female patients, using 137 long length and 82 standard length cemented collarless double-taper femoral stems in 211 patients, with a mean age of 72 years (30 to 90) and mean follow-up of six years (two to 18) have been described previously. We have extended the follow-up to a mean of 13 years (8 to 20) in this cohort of patients in which the pre-operative bone deficiency Paprosky grading was IIIA or worse in 79% and 73% of femurs with long and standard stems, respectively. For the long stem revision group, survival to re-revision for aseptic loosening at 14 years was 97% (95% confidence interval (CI) 91 to 100) and in patients aged > 70 years, survival was 100%. Two patients (two revisions) were lost to follow-up and 86 patients with 88 revisions had died. Worst-case analysis for survival to re-revision for aseptic loosening at 14 years was 95% (95% CI 89 to 100) and 99% (95% CI 96 to 100) for patients aged > 70 years. One additional long stem was classified as loose radiographically but not revised. For the standard stem revision group, survival to re-revision for aseptic loosening at 14 years was 91% (95% CI 83 to 99). No patients were lost to follow-up and 49 patients with 51 hips had died. No additional stems were classified as loose radiographically. Femoral revision using a cemented collarless double-taper stem, particularly with a long length stem, and in patients aged > 70 years, continues to yield excellent results up to 20 years post-operatively, including in hips with considerable femoral metaphyseal bone loss.