Julien Girard

Biomechanical reconstruction of the hip : A randomised study comparing total hip resurfacing and total hip arthroplasty

We have compared the biomechanical nature of the reconstruction of the hip in conventional total hip arthroplasty (THA) and surface replacement arthroplasty (SRA) in a randomised study involving 120 patients undergoing unilateral primary hip replacement. The contralateral hip was used as a control. Post-operatively, the femoral offset was significantly increased with THA (mean 5.1 mm; -2.8 to 11.6) and decreased with SRA (mean -3.3 mm; -8.9 to 8.2). Femoral offset was restored within sd 4 mm in 14 (25%) of those with THA and in 28 (57%) of the patients receiving SRA (p < 0.001). In the THA group, the leg was lengthened by a mean of 2.6 mm (-6.04 to +12.9), whereas it was shortened by a mean of 1.9 mm (-7.1 to +2.05) in the SRA group, compared with the contralateral side. Leg-length inequality was restored within sd 4 mm in 42 (86%) of the SRA and 33 (60%) of the THA patients. The radiological parameters of acetabular reconstruction were similar in both groups. Restoration of the normal proximal femoral anatomy was more precise with SRA. The enhanced stability afforded by the use of a large-diameter femoral head avoided over-lengthening of the limb or increased offset to improve soft-tissue tension as occurs sometimes in THA. In a subgroup of patients with significant pre-operative deformity, restoration of the normal hip anatomy with lower pre-operative femoral offset or significant shortening of the leg was still possible with SRA.

A randomised study comparing resection of acetabular bone at resurfacing and total hip replacement

We have undertaken a prospective, randomised study to compare conservation of acetabular bone after total hip replacement and resurfacing arthroplasty of the hip. We randomly assigned 210 hips to one of the two treatment groups. Uncemented, press-fit acetabular components were used for both. No significant difference was found in the mean diameter of acetabular implant inserted in the groups (54.74 mm for total hip replacement and 54.90 mm for resurfacing arthroplasty). In seven resurfacing procedures (6.8%), the surgeon used a larger size of component in order to match the corresponding diameter of the femoral component. With resurfacing arthroplasty, conservation of bone is clearly advantageous on the femoral side. Our study has shown that, with a specific design of acetabular implant and by following a careful surgical technique, removal of bone on the acetabular side is comparable with that of total hip replacement.

Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: A FOLLOW-UP STUDY

We have updated our previous randomised controlled trial comparing release of chromium (Cr) and cobalt (Co) ions and included levels of titanium (Ti) ions. We have compared the findings from 28 mm metal-on-metal total hip replacement, performed using titanium CLS/Spotorno femoral components and titanium AlloFit acetabular components with Metasul bearings, with Durom hip resurfacing using a Metasul articulation or bearing and a titanium plasma-sprayed coating for fixation of the acetabular component. Although significantly higher blood ion levels of Cr and Co were observed at three months in the resurfaced group than in total hip replacement, no significant difference was found at two years post-operatively for Cr, 1.58 microg/L and 1.62 microg/L respectively (p = 0.819) and for Co, 0.67 microg/L and 0.94 microg/L respectively (p = 0.207). A steady state was reached at one year in the resurfaced group and after three months in the total hip replacement group. Interestingly, Ti, which is not part of the bearing surfaces with its release resulting from metal corrosion, had significantly elevated ion levels after implantation in both groups. The hip resurfacing group had significantly higher Ti levels than the total hip replacement group for all periods of follow-up. At two years the mean blood levels of Ti ions were 1.87 microg/L in hip resurfacing and and 1.30 microg/L in total hip replacement (p = 0.001). The study confirms even with different bearing diameters and clearances, hip replacement and 28 mm metal-on-metal total hip replacement produced similar Cr and Co metal ion levels in this randomised controlled trial study design, but apart from wear on bearing surfaces, passive corrosion of exposed metallic surfaces is a factor which influences ion concentrations. Ti plasma spray coating the acetabular components for hip resurfacing produces significantly higher release of Ti than Ti grit-blasted surfaces in total hip replacement.

Metal Ion Release With Large-Diameter Metal-on-Metal Hip Arthroplasty

Preoperative and postoperative ion concentrations were measured in 29 metal-on-metal, large-diameter head total hip arthroplasty (LDH-THA) patients. Mean chromium, cobalt (Co), and titanium levels from LDH-THA were 1.3, 2.2, and 2.7 μg/L at 12 months. The open femoral head design showed significantly higher Co concentrations than the closed design (3.0 vs 1.8 μg/L, P = .037). Compared with previously published ion levels from a hip resurfacing system presenting the same bearing characteristics, Co levels were significantly higher in LDH-THA (2.2 vs 0.7 μg/L, P < .001). This study has demonstrated that the addition of a sleeve with modular junctions and an open femoral head design of LDH-THA causes more Co release than bearing surface wear (157% and 67%, respectively). Even if no pathologic metal ion threshold level has been determined, efforts should be made to minimize its release. We recommend modification or abandonment of the modular junction and femoral head open design for this specific LDH-THA system.

Activités sportives après resurfaçage et prothèse totale de hanche : une étude prospective randomisée

PURPOSE OF THE STUDY Since component wear of the prosthetic metal-polyethylene bearing is directly related to the level of patient activity, it would be logical, for patients with a total hip arthroplasty, to advise against long-term participation in activities with repeated movements The purpose of this prospective randomized study was to compare the type, intensity and frequency of sports activities performed after resurfacing hip arthroplasty (RH) or total hip arthroplasty (THA) using a metal-on-metal bearing. MATERIAL AND METHODS This study concerned 205 hips, including 152 with a unilateral hip arthroplasty (71 THA and 81 RH). Three clinical scores were used: an overall activity score, the University of California, Los Angeles (UCLA) score and the Western Ontario McMaster Osteoarthritis Index (WOMAC) score, as well as patient satisfaction, return to sports activities (using a visual analog scale [VAS]) and frequency of factors limiting activity. Patients completed a questionnaire to determine the type, intensity and frequency of sports activities practiced pre- and postoperatively. RESULTS The mean overall activity score immediately before surgery was not statistically different between the two groups (p=0.111). One year after surgery, the score was 17.9 in the RH group and 12.4 in the THA group (p=0.001). At last follow-up, the mean WOMAC score was 8.1 (range 0-73, S.D. 13.1) in the RH group and 9.8 (range 0-41, S.D. 10.9) in the THA group (p=0.409). The mean UCLA score was 7.17 in the RH group (range 2-10, S.D. 1.90) and 6.75 in the THA group (range 2-10, S.D. 1.71) (p=0.174). The mean satisfaction with return to sports activities as assessed on the VAS was 7.78 in the RH group and 7.43 in the THA group (p=0.313). DISCUSSION The results of this study demonstrate that the degree and intensity of postoperative sports activities are greater in the RH group than in the THA group, although this difference was less pronounced than expected. The excellent joint stability after RH (big head effect) could be one of the main factors favoring a high activity level compared to conventional THA, by limiting the episodes of dislocation and increasing the suction effect between the joint components. It is nevertheless difficult to ascertain the long-term effect of intense sports activity on the fixation of osteo-integrated implants (cups) and cemented components (femoral stem).

The Durom Large Diameter Head acetabular component: EARLY RESULTS WITH A LARGE-DIAMETER METAL-ON-METAL BEARING

Implantation of a large-diameter femoral head prosthesis with a metal-on-metal bearing surface reduces the risk of dislocation, increases the range of movement, minimises the risk of impingement and, in theory, results in little wear. Between February 2004 and March 2007 we implanted 100 consecutive total hip replacements with a metal-on-metal bearing and a large femoral head into 92 patients. There were 51 men and 41 women with a mean age of 50 years (18 to 70) at the time of surgery. Outcome was assessed using the Western Ontario McMaster University osteoarthritis index and the Harris hip score as well as the Devane activity score. These all improved significantly (p < 0.0001). At the last follow-up there were no cases of dislocation, no impingement, a good range of movement and no osteolysis, but seven revisions, two for infection and five for aseptic loosening. The probability of groin pain increased if the other acetabular component inclination exceeded 50 degrees (p = 0.0007). At 4.8 years of follow-up, the projected survival of the Durom acetabular component, with revision for any reason, was 92.4% (sd 2.8) (95% confidence interval 89.6 to 95.2). The design of the component made it difficult both to orientate and seat, which when combined with a poor porous coating, produced unpredictable fixation and a low survival at five years.

Low Rate of Dislocation of Dual-mobility Cups in Primary Total Hip Arthroplasty

BackgroundDual-mobility (DM) cups were introduced to minimize the risk of THA dislocation. The overall rate of dislocation of DM cups (including both large and small articulations) is controversial and ranges from 0% to 5% in previous studies.Questions/purposesWe therefore recorded (1) the dislocation rate, (2) loosening and osteolysis, and (3) subsequent related revisions with DM cups.MethodsBetween 1998 and 2003, 2480 primary THAs with DM cups were undertaken in 2179 patients. The mean age was 69 years (range, 19–94 years). This group underwent specific clinical and radiographic evaluation at a minimum followup of 0.17 years (mean, 7 years; range, 0.17–11 years) to assess dislocation, reoperation, osteolysis, and cup fixation.ResultsThere were 22 dislocations (0.88%): 15 dislocations of large articulations (0.6%), with two (0.08%) recurring but only one requiring revision (0.04%), and seven intraprosthetic small articulation dislocations (0.28%), all needing revision surgery. At last followup, mean Harris hip score was 91 (range, 60–100); 2439 cups (98%) showed no signs of loosening; and 141 patients (145 hips) had osteolysis (6%). Osteolysis and cup loosening were more frequent in patients younger than 50 years at the time of surgery. The 10-year survivorship considering revision for any reason was 93% (95% CI, 91%–95%).ConclusionsDM cups had a low dislocation rate in primary THA, with a limited frequency of adverse effects. We recommend DM cups to minimize dislocation in populations at high risk for instability, but they should be avoided in younger, active patients at higher risk for osteolysis.Level of EvidenceLevel IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Fiabilité limitée du plan pelvien antérieur pour l'implantation assistée par informatique de la cupule d'une prothèse totale de hanche

Resume Le plan pelvien anterieur ou plan de Lewinnek est couramment utilise comme plan de reference pour guider la navigation informatique en vue de l’implantation d’une cupule de prothese totale de hanche (PTH). Des cliches radiographiques de bassin de profil strict en qualite argentique de 106 sujets ont servi de materiel d’etude. Ces 106 sujets se repartissaient en : 82 porteurs d’une PTH (40 ayant eu une luxation et 42 ayant une PTH stable choisis par tirage au sort) et 24 sujets temoins indemnes de pathologie. Dix-neuf des 42 patients porteurs d’une PTH stable ont eu un cliche avant et apres la pose de l’arthroplastie, les 24 temoins ont eu un cliche de profil en position couchee et debout. Trente-huit pour cent des sujets avaient en orthostatisme une orientation du plan pelvien anterieur en dehors d’une fourchette de ± 5 ° par rapport a la verticale et 13 % au-dela d’une fourchette de ± 10 °. Le passage de la position debout a la position couchee influencait de maniere significative (p = 0,002) l’orientation du plan pelvien anterieur avec des variations extremes comprises dans une fourchette de plus de 20 °, la moitie de la population variant de plus de 7 °. Les variations de l’orientation du plan pelvien anterieur par rapport a la verticale nous conduisent a penser qu’il ne s’agit pas d’une reference fiable pour l’orientation de la cupule d’une PTH puisque l’on risque de se tromper 1 fois sur 3 de plus de 10 °, soit la moitie de la valeur de l’anteversion anatomique de l’acetabulum. Une assistance informatique a la pose d’une PTH sans imagerie preoperatoire doit, soit beneficier d’un repere plus fiable, soit s’affranchir d’un plan de reference en utilisant une approche cinematique de la hanche operee.

Range of motion of large head total hip arthroplasty is greater than 28 mm total hip arthroplasty or hip resurfacing.

BACKGROUND Reduced range of motion of the hip has a detrimental influence on lower limb function. Large diameter head total hip arthroplasty may theoretically have a greater potential for restoring normal hip range of motion due to greater head-neck diameter ratio, and hence provide better function compared to conventional or hip resurfacing arthroplasty. METHOD At minimum one year follow-up, range of motion of the operated and contra lateral hips was clinically assessed using digital photographs and bony landmarks in a clinical comparative study. We assessed if 1) large diameter head total hip arthroplasty (55 patients) restores better hip range of motion compared to 28 mm total hip arthroplasty (50 patients) or hip resurfacing (60 patients) 2) large diameter head total hip arthroplasty achieves same hip range of motion as contra lateral normal hips and 3) hip range of motion correlates with the WOMAC score. FINDINGS The large diameter head total hip arthroplasty group had significantly greater total arcs of motion (approximately 20°), mostly due to an increase of hip flexion and external rotation, but did not reach normal hip motion. The hip range of motion showed significant correlation with the WOMAC score, especially the flexion arc. INTERPRETATION The better hip range of motion of large diameter head total hip arthroplasty is likely due to the greater head to neck diameter ratio and hence seems to be the best option to optimize range of hip motion and improve function after hip arthroplasty.

Residual groin pain at a minimum of two years after metal-on-metal THA with a twenty-eight-millimeter femoral head, THA with a large-diameter femoral head, and hip resurfacing.

BACKGROUND Groin pain may persist in up to 4.3% of patients after total hip arthroplasty and up to 18% of patients one year after hip resurfacing. The incidence of this problem after total hip arthroplasty with a large-diameter femoral head is unknown. METHODS We analyzed the natural history of groin pain and its clinical consequences during the first two years after three types of hip arthroplasty. Data were collected prospectively on 279 patients. Eighty-five patients had a polyethylene sandwich metal-on-metal total hip arthroplasty with a 28-mm-diameter femoral head, 105 had hip resurfacing, and eighty-nine had a total hip arthroplasty with a large-diameter femoral head component with three other cup designs (forty-nine in this group had the same monoblock acetabular cup design as those who had hip resurfacing). RESULTS At the twenty-four-month follow-up evaluation, seventy-seven patients (28%) reported at least one painful area around the hip and thirty-four patients (12.2%) had pain at more than one location. At three months, the incidence of groin discomfort was significantly increased in those who had hip resurfacing (30.5%) and in those who had total hip arthroplasty with a large-diameter femoral head (30%) compared with those who had total hip arthroplasty with a 28-mm femoral head (18.3%). This incidence decreased at two years (14.9%, 16.9%, and 12.9%, respectively). At twenty-four months postoperatively, eleven (four who had hip resurfacing, six who had total hip arthroplasty with the large-diameter head, and one who had total hip arthroplasty with the 28-mm head) of forty-one patients who had groin pain had not reported groin pain at previous follow-up evaluations. Of the forty-one patients reporting groin pain at the time of the last follow-up, twenty-three patients (56%) did not seek further evaluation or treatment, nine had revision surgery (22%), and the remaining nine patients thought the pain was substantial enough to warrant further evaluation and treatment. CONCLUSIONS When the exact source of groin pain cannot be found after total hip arthroplasty, careful follow-up should be done as local reactions to metal-on-metal implants and component loosening may take time to become apparent clinically or on imaging studies.