Assessment of acetabular cup positioning from a lateral radiographic projection after total hip replacement.

OBJECTIVE To demonstrate first that a ventrodorsal radiographic (VDR) projection is inadequate for obtaining accurate acetabular cup position (ACP) measurements after total hip replacement (THR), and second to validate use of the lateral radiographic (LR) projection to measure ACP. STUDY DESIGN In vitro study. METHODS Eleven VDRs were obtained after insertion of a cup into the acetabulum of a Sawbones pelvis fixed at an approximated angle. For each VDR, the pelvis was placed in varying degrees of craniocaudal pelvic tilt (CCPT). Fifteen LRs were obtained of a Sawbones pelvis with varying ACPs. Five blinded observers made previously described measurements of ACP on each VDR and angle of lateral opening (ALO) and coronal retroversion (CR) on each LR. RESULTS An almost perfect level of agreement was observed between 5 observers for the repeatability of both VDR and LR measurements. When varying degrees of CCPT were introduced, there was no agreement in the measurements of ACP from VDRs. In all cases, and at all ACPs, measurements taken from LRs were in agreement. CONCLUSION Undetectable CCPT causes significant variability in ACP measurements on VDRs predisposing postoperative radiographic measurements to inaccuracy. Measurements obtained from an LR of CR and ALO are accurate and consistent between observers and it should be used to measure ACP. The VDR should be performed to assess bone and implant integrity but not to obtain measurements of ACP because of CCPT causing measurements to be unreliable. Measurements of ACP obtained from an LR in conjunction with femoral anteversion may allow for investigation of the influence of ACP on coxofemoral joint luxation after THR.

[1]  T. Guerrero,et al.  Zurich cementless total hip replacement: retrospective evaluation of 2nd generation implants in 60 dogs. , 2009, Veterinary surgery : VS.

[2]  W. Liska,et al.  Sciatic neurapraxia as a complication in 1000 consecutive canine total hip replacements. , 2008, Veterinary surgery : VS.

[3]  Laura L. Nelson,et al.  Risk factors for ventral luxation in canine total hip replacement. , 2007, Veterinary surgery : VS.

[4]  A. Kapatkin,et al.  Complications and radiographic findings following cemented total hip replacement , 2006, Veterinary and Comparative Orthopaedics and Traumatology.

[5]  M. Krismer,et al.  Reducing the risk of dislocation after total hip arthroplasty: the effect of orientation of the acetabular component. , 2005, The Journal of bone and joint surgery. British volume.

[6]  W. Liska.  Femur fractures associated with canine total hip replacement. , 2004, Veterinary surgery : VS.

[7]  J. Dyce,et al.  Acetabular cup displacement after polyethylenecement interface failure: A complication of total hip replacement in seven dogs , 2003, Veterinary and Comparative Orthopaedics and Traumatology.

[8]  T. Kubo,et al.  Effect of Acetabular Cup Position and Orientation in Cemented Total Hip Arthroplasty , 2001, Clinical orthopaedics and related research.

[9]  J. Dyce,et al.  Radiographic evaluation of acetabular component position in dogs. , 2001, Veterinary surgery : VS.

[10]  J. Dyce,et al.  Evaluation of risk factors for luxation after total hip replacement in dogs. , 2000, Veterinary surgery : VS.

[11]  A. Cross,et al.  Acetabular component orientation as an indicator of implant luxation in cemented total hip arthroplasty. , 2000, Veterinary surgery : VS.

[12]  A. Cross,et al.  Definition and determination of acetabular component orientation in cemented total hip arthroplasty. , 2000, Veterinary surgery : VS.

[13]  K. Schulz.  Application of arthroplasty principles to canine cemented total hip replacement. , 2000, Veterinary surgery : VS.

[14]  D. Marcellin-Little,et al.  Femoral medullary infarction secondary to canine total hip arthroplasty. , 2000, Veterinary surgery : VS.

[15]  Ton J. Cleophas,et al.  Statistics Applied to Clinical Trials , 2000 .

[16]  D. Deyoung,et al.  Canine uncemented porous-coated anatomic total hip arthroplasty: results of a long-term prospective evaluation of 50 consecutive cases. , 1999, Veterinary surgery : VS.

[17]  Schwarz Pd,et al.  Aseptic loosening of the femoral implant after cemented total hip arthroplasty in dogs: 11 cases in 10 dogs (1991-1995). , 1997 .

[18]  B. Massat,et al.  Clinical and radiographic results of total hip arthroplasty in dogs: 96 cases (1986-1992). , 1994, Journal of the American Veterinary Medical Association.

[19]  H. Paul,et al.  A modified technique for canine total hip replacement , 1987 .

[20]  M. Olmstead.  Total hip replacement. , 1987, The Veterinary clinics of North America. Small animal practice.

[21]  R. B. Hohn,et al.  A five-year study of 221 total hip replacements in the dog. , 1983, Journal of the American Veterinary Medical Association.

[22]  R. B. Hohn,et al.  RADIOGRAPHIC EVALUATION OF TOTAL HIP REPLACEMENT IN THE DOG , 1982 .