A Robotic Model of Hip Dislocation Potential: Total Hip Arthroplasty Versus Femoral Head Resurfacing

Author(s):  
R. W. Colbrunn ◽  
J. J. Bottros ◽  
C. B. Greeson ◽  
A. van den Bogert ◽  
W. K. Barsoum

Hip dislocation often results from neck impingement and subsequent subluxation. Having a model to study impingent-free range of motion (ROM) and dislocation potential at the impingement postures can elucidate the contribution to joint stability of prosthetic design, component position, anatomical variables, and biomechanical factors. Much controversy surrounds the resurgence of femoral head resurfacing (FHR) and its biomechanical implications of retaining the femoral neck, particularly its head-neck ratio. We have developed a dynamic cadaveric robotics model that functions in real time under load-control parameters to recreate in vivo hip mechanics. This study specifically identifies and compares the impingent-free ROM and a stability index value that quantifies the dislocation potential in the native hip, femoral head resurfacing and total hip replacement (size 28, 36mm femoral heads).

2018 ◽  
Vol 29 (6) ◽  
pp. 647-651 ◽  
Author(s):  
Giuseppe Valente ◽  
Brent Lanting ◽  
Steven MacDonald ◽  
Matthew G Teeter ◽  
Douglas Van Citters ◽  
...  

Introduction:Material loss at the head-neck junction in total hip arthroplasty may cause adverse clinical symptoms and implant failure. The purpose of this study was to quantitatively examine the effects of head size, stem material and stem offset on material loss of the head-neck taper interface of a single trunnion design in retrieval implants of metal on polyethylene bearing surfaces.Methods:A retrieval study was performed to identify all 28-mm and 32-mm femoral heads from a single implant/taper design implanted for >2 years. This included n = 56 of the 28-mm heads and n = 23 of the 32-mm heads. The 28-mm femoral heads were matched to 32-mm femoral heads based on time in vivo and head length. A coordinate measuring machine was used to determine maximum linear corrosion depth (MLD). Differences in MLD for head diameter, stem material, and stem offset were determined.Results:There were no differences between groups for age, gender, BMI, or implantation time. There was no difference in MLD between 28 mm and 32 mm matched paired head diameters ( p = 0.59). There was also no difference in MLD between titanium or cobalt-chromium stems ( p = 0.79), and regular or high-offset stems ( p = 0.95).Conclusion:There is no statistical difference in femoral head MLD at the head-neck junction in THA between 28-mm and 32-mm matched paired femoral heads, similar or mixed alloy coupled femoral head stem constructs, and regular or high offset stems.


Author(s):  
D. A. Glaser ◽  
R. D. Komistek ◽  
H. E. Cates ◽  
M. Mahfouz

The major complications following total hip replacement (THA) are implant loosening, dislocation, instability, fracture and infection. It is hypothesized that vibration, in the range of the resonance frequencies, may cause pain, bone degeneration and fracture. A further understanding of the physical response resulting from impact during femoral head sliding may lead to valuable insight pertaining to THA failure. Therefore, the first objective of this present study was to determine if frequencies propagating through the hip joint near resonant frequencies may lead to wear or loosening of the components. Recently, studies found that femoral head sliding, often referred to as hip separation, between the acetabulum cup and the femoral head does occur, which may also play a role in complications observed with THA today, but a the effects of hip separation and the causes of its occurrence has not been studied as jet. Therefore, the second objective of this study was to determine if a sound sensor, externally attached, could be used to correlate impact loading sounds from femoral head sliding in the acetabular cup. Additional objective of this study was to develop a mathematical model that better simulates the in vivo loading conditions of total hip replacement patients using in vivo fluoroscopic and ground reaction data as input.


2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Alexander Schuh ◽  
Ralph Schuh ◽  
Albert Fujak ◽  
Wolfgang Hönle ◽  
Sandeep Kashyap

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Babaji Thorat ◽  
Avtar Singh ◽  
Mohammad Arshad ◽  
Sharad Salokhe ◽  
Ravi Mavani

Introduction: Traumatic posterior hip dislocation with comminuted fracture of the ipsilateral acetabulum and femoral neck is a rare fracture pattern. These injuries are associated with high energy trauma and pose challenges during management. Controversy exists between hip preservation and replacement surgeries in middle-age patients. Open reduction and internal fixation (ORIF) have a high risk of non-union, avascular necrosis, and post-traumatic osteoarthritis of hip requiring total hip arthroplasty hip replacement (THA) as a secondary procedure later. Case Report: A 56-year-old male presented with posterior hip dislocation and comminuted fracture of ipsilateral wall and column of the acetabulum, and femoral neck following a high energy trauma. He was managed by acetabular reconstruction using femoral head structural autograft combined with acute primary uncemented THA. At 2-year follow-up, the patient had good functional outcome with a satisfactory range of motion without any difficulty in weight-bearing and doing his daily activities. Conclusion: Although uncommon, acetabular reconstruction using femoral head structural autograft and acute primary uncemented THA is a viable alternative treatment option compared to ORIF in middle-age patients with fracture of ipsilateral neck and acetabulum. This facilitates post-operative rehabilitation and avoids further operations for possible developing AVN or secondary arthritis. Keywords: Hip dislocation, acetabulum fracture, femur neck fracture, acute total hip arthroplasty, acetabular reconstruction, femoral head structural autograft.


Author(s):  
D Bennett ◽  
J F Orr ◽  
D E Beverland ◽  
R Baker

Wear of the polyethylene acetabular component is the most serious threat to the long-term success of total hip replacements (THRs). Greatly reduced wear rates have been reported for unidirectional, compared to multidirectional, articulation in vitro. This study considers the multidirectional motions experienced at the hip joint as described by movement loci of points on the femoral head for individual THR patients. A three-dimensional computer program determined the movement loci of selected points on the femoral head for THR patients and normal subjects using kinematic data obtained from gait analysis. The sizes and shapes of these loci were quantified by their sliding distances and aspect ratios with substantial differences exhibited between individual THR patients. The average sliding distances ranged from 10.0 to 18.1 mm and the average aspect ratios of the loci ranged from 2.5 to 9.2 for the THR patients. Positive correlations were found between wear rate and average sliding distance, the inverse of the average aspect ratio of the loci and the product of the average sliding distance and the inverse of the average aspect ratio of the loci. Patients with a normal hip joint range of motion produce multidirectional motion loci and tend to experience more wear than patients with more unidirectional motion loci. Differing patterns of multidirectional motion at the hip joint for individual THR patients may explain widely differing wear rates in vivo.


2018 ◽  
Vol 2018 ◽  
pp. 1-4 ◽  
Author(s):  
Saif Shamshoon ◽  
Patrick Thornley ◽  
Justin de Beer

We describe a case of aseptic failure with profound femoral stem trunnion wear and femoral head dissociation nine years after initial primary total hip arthroplasty (THA) with the Stryker Accolade total hip arthroplasty system. Current guidelines for postoperative care and follow-up after THAs as potential intervention points for early detection of prosthetic joint failure are also reviewed.


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