Wear & Osteolysis Basic Science

Author: Jason McKean

Topic updated on 05/27/13 12:56am

Introduction

Osteolysis represents a histiocytic response to wear debris.
Steps in the process include (see below)
1. particulate debris formation
2. macrophage activated osteolysis
3. prosthesis micromotion
4. particulate debris dissemination
Evaluation
- radiostereometric analysis
  - is the most accurate and precise technique to evaluate polyethylene wear
  - uses radiopaque tantalum beads planted in the bone to follow the position of the components relative to the beads on radiographs.

Step 1: Particulate Debris Formation

Types of wear
- adhesive wear
  - most important in osteolytic process
  - microscopically PE sticks to prosthesis and debris gets pulled off
- abrasive wear
  - cheese grater effect of prosthesis scraping off particles
- third body wear
  - particles in joint space cause abrasion and wear
- volumetric wear
  - main determinant of number of particles created
  - directly related to square of the radius of the head
  - volumetric wear more or less creates a cylinder
    - V=3.14rsquaredw
    - V is volumetric wear, r is the radius of head, w is linear head wear
    - head size is most important factor in predicting particles generated
- linear wear
  - is measured by the distance the prosthesis has penetrated into the liner
Wear leads to particulate debris formation
- wear rates by material
  - polyethylene
    - non-cross linked UHMWPE wear rate is 0.1-0.2 mm/yr
      - linear wear rates greater than 0.1 mm/yr has been associated with osteolysis and subsequent component loosening
    - highly-cross linked UHMWPE generates smaller wear particles and is more resistant to wear (but has reduced mechanical properties compared to conventional non-highly cross-linked)
    - factors increasing wear in THA
      - thickness < 6mm
      - malalignment of components
      - patients < 50 yo
      - men
      - higher activity level
  - ceramics
    - ceramic bearings have the lowest wear rates of any bearing combination (0.5 to 2.5 µ per component per year)
    - ceramic-on-polyethylene bearings have varied, ranging from 0 to 150 µ.
    - has a unique complication of stripe wear occurring from lift-off separation of the head gait
    - recurrent dislocations or incidental contact of femoral head with metallic shell can cause "lead pencil-like" markings that lead to increased femoral head roughness and polyethylene wear rates.
  - metals
    - metal-on-metal produces smaller wear particles as well as lower wear rates than those for metal-on-polyethylene bearings (ranging from 2.5 to 5.0 µ per year)
    - titanium used for bearing surfaces has a high failure rate because of a poor resistance to wear and notch sensitivity.
    - metal-on-metal wear stimulates lymphocytes
Particulate Type
- UHMWPE
  - most common
- PMMA
- Co-Cr
- Ti
- third-body
Particulate size
- is < 1 micron

Step 2: Macrophage Activated Osteoclastogenesis and Osteolysis

Macrophage activation
- results in macrophage activation and further macrophage recruitment
- macrophage releases osteolytic factors (cytokines) including
  - TNF- alpha
  - TGF-beta
  - osteoclast activating factor
  - oxide radicals
  - hydrogen peroxide
  - acid phosphatase
  - interleukins
  - prostaglandins
Osteoclast activation and osteolysis
- increase of TNF- alpha increases RANK
- increase of VEGF with UHMWPE inhances RANK and RANKL activation
  - RANKL mediated bone resoption
    - an increase in production of RANK and RANKL gene transcripts leads to osteolysis

Step 3: Prosthesis Micromotion

Osteolysis surrounding the prosthesis leads to micromotion
- micromotion leads to increase particle wear and further prosthesis loosening
- N-telopeptide urine level is a marker for bone turnover and are elevated in osteolysis

Step 4: Debris Dissemination

Increase in hydrostatic pressure leads to dissemination of debris into effective joint space
- increased hydrostatic pressure is result of inflammatory response
- dissemination of debris into effective joint space further propagates osteolysis
- circumferentially coated prosthesis limits osteolysis in the distal femur

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Qbank (19 Questions)

TAG

(OBQ12.68) Which of the following is indicative of type 1 collagen breakdown and can be utilized as a marker of bone turnover? Topic

Review Topic

1. Increased urinary N-telopeptide
2. Increased urinary cAMP and phosphate
3. Increased urinary phosphoethanolamine
4. Increased urinary Bence Jones proteins
5. Increased serum bone sialoprotein

PREFERRED RESPONSE ▶

DISCUSSION: Urinary N-telopeptide is a marker of increased bone turnover and is a breakdown product of Type 1 collagen.

Increased serum alkaline phosphatase level and increased urinary markers of N-telopeptide, hydroxylproline, deoxypyridinoline indicate high bone turnover and can be seen in metabolic bone diseases such as Paget's disease.

von Schewelov et al. reviewed 160 patients that underwent total hip replacements and examined their urine specimens to see if N-telopeptide levels correlated to periprosthetic osteolysis. They found that n-telopeptide levels were 1/3 higher in the patients that had evidence of osteolysis. N-telopeptide release and annual wear were both associated with increased prevalence of osteolysis in the study.

Illustration A shows a radiograph of Pagets disease, an example of a condition where there is an increased level of N-telopeptide in the urine. Illustration B is a radiograph showing periprosthetic osteolysis, another condition where there is an increased level of N-telopeptide in the urine.

Incorrect Answers:
Answer 2: Increased urinary cAMP is found in Type 2 pseudohypoparathyroidism.
Answer 3: Phosphoethanolamine is found in the urine in patients with hypophosphatasia.
Answer 4: Bence Jones proteins are found in the urine of patients with multiple myeloma.
Answer 5: Bone sialoprotein (BSP) is a component of mineralized tissues such as bone, dentin, cementum and calcified cartilage.

Illustrations: A

REFERENCES:

1. von Schewelov TV, Carlsson A, Dahlberg L. Cross-linked N-telopeptide of type I collagen (NTx) in urine as a predictor of periprosthetic osteolysis. Journal of Orthopaedic Research. 2006; 24(7):1342-1348. PMID:16718682 (Link to Abstract)

Question Authors:

Michael Hughes MD, Derek Moore, John Badylak MD, Stephen Incavo MD,

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(OBQ11.191) A 56-year-old man reports progressively worsening left knee pain after undergoing total knee arthroplasty 6 years ago. He was initially very happy with his progress, but 18 months after surgery he began to have knee pain. Radiographs are shown in Figures A and B. Laboratory values reveal a C-reactive protein of 0.1 mg/dL (normal 0.0-0.6 mg/dL) and an erythrocyte sedimentation rate of 3 mm/h (normal 0-15 mm/h). An aspiration of the knee reveals 157 leukocytes/ml with 18% polymorphonucleocytes. What is the most appropriate next step in management? Topic

Review Topic

FIGURES: A

1. One-stage revision
2. Irrigation and debridement with polyethylene spacer exchange
3. Antibiotic impregnated cement spacer placement
4. Two-stage revision
5. Broad-spectrum, empiric oral antibiotics

PREFERRED RESPONSE ▶

DISCUSSION: The history, radiographs, and laboratory values are consistent with aseptic loosening. The lateral radiograph demonstrates a thin cement mantle that has separated from the prosthesis. The question stem details that infection is not likely given the normal serology and aspirate values. A one-stage revision of the arthroplasty components is the most appropriate next step in management among the options provided.

Brown and Bartel present a Level 5 review of the intrinsic and extrinsic factors that can effect wear behavior in arthroplasty bearing surfaces. They state that increased sliding distance, third body wear, and impingement can be sources for accelerated wear rates of bearings.

Gonzalex and Mekhail present a Level 5 review discussing the etiologies for a failed joint arthroplasty. Sources identified for continued pain were aseptic loosening, component failure, patellar dysfunction, infection, or complex regional pain syndrome.

REFERENCES:

1. Brown TD, Bartel DL. Implant Wear Symposium 2007 Engineering Work Group. What design factors influence wear behavior at the bearing surfaces in total joint replacements? J Am Acad Orthop Surg. 2008;16 Suppl 1:S101-6. PMID:18612003 (Link to Abstract)

2. Gonzalez MH, Mekhail AO. The failed total knee arthroplasty: evaluation and etiology. J Am Acad Orthop Surg. 2004 Nov-Dec;12(6):436-46. Review. PMID:15615509. (Link to Abstract)

Question Authors:

Michael Hughes MD, John Badylak MD, Ben Taylor MD,

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(OBQ10.39) A 45-year-old male, with a history of avascular necrosis, undergoes a total hip arthroplasty using a metal-on-metal bearing. Which of the following statements regarding the use of metal-on-metal bearings is true? Topic

Review Topic

1. Produce lower serum metal ion concentrations than metal-on-cross linked polyethylene bearings
2. Have a decreased volumetric wear rate compared to metal-on-ceramic bearings
3. Have smaller wear particles compared to metal-on-cross linked polyethylene bearings
4. Have a higher incidence of early soft-tissue sarcoma compared to all other bearing surfaces.
5. The wear rate significantly increases after the first year of use.

PREFERRED RESPONSE ▶

DISCUSSION: Metal-on-metal bearings used in total hip arthroplasty form smaller wear particles compared to metal-on-cross linked polyethylene bearings. Metal-on-metal bearings produce higher serum metal ion concentrations, have lower volumetric wear rates, and achieve a "steady state" of wear after the first year of use whereby the wear rate then decreases. The volumetric wear rate of metal-on-metal articulations is greater than metal-on-ceramic as reported by in vitro studies. Also, there is not evidence to suggest an increased risk of soft tissue sarcoma with use of the metal-on-metal bearings.

Heisel et al, in an instructional lecture series, systematically discusses all types of bearing options with their advantages and disadvantages.

Amstutz et al attempts to answer questions and concerns over the use of metal-on-metal bearings for total hip arthroplasty.

REFERENCES:

1. Amstutz HC, Campbell P, McKellop H, Schmalzreid TP, Gillespie WJ, Howie D, Jacobs J, Medley J, Merritt K. Metal on metal total hip replacement workshop consensus document. Clin Orthop Relat Res. 1996 Aug;(329 Suppl):S297-303. PMID:8769344 (Link to Abstract)

2. Heisel C, Silva M, Schmalzried TP. Bearing surface options for total hip replacement in young patients. Instr Course Lect. 2004;53:49-65. Review. PMID:15116600 (Link to Abstract)

Question Authors:

John Badylak MD, Michael Hughes MD, Ben Taylor MD,

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(OBQ10.116) A new biomaterial has been designed for hard on soft bearings in total hip arthroplasty. The implant company claims this new material has a lower wear rate and greater toughness than highly cross linked polyethylene. Which of the following studies would most accurately evaluate wear between the two materials? Topic

Review Topic

1. Retrospective review of each material with immediate post-operative radiographs compared to annual follow-up radiographs
2. Prospective trial comparing each material with radiostereometric analysis
3. Prospective trial comparing each material with annual CT scans
4. Prospective trial comparing each material with computer-assisted edge-detection radiographs
5. Retrospective trial comparing each material with computer-assisted edge-detection radiographs

PREFERRED RESPONSE ▶

DISCUSSION: Radiostereometric analysis is the most effective method to evaluate polyethylene wear in arthroplasty. Radiopaque tantalum beads are inserted into the bone in strategic positions surrounding the implants. An immediate post-operative film records the position of the beads. The construct can then be followed with repeated radiographs over time by evaluating the position of the components relative to the beads. Bragdon et al used radiostereometric analysis to compare wear rates of highly cross linked polyethylene with 28 mm and 36 mm femoral heads. No differences were discovered in femoral head penetration between the two groups. McCalden et al summarizes the different methods available to evaluate polyethylene wear following total hip arthroplasty. Notably, radiostereometric analysis is the most accurate and precise, but is also expensive, requires technical expertise, and can only be used in a prospective manner.

REFERENCES:

1. Bragdon CR, Greene ME, Freiberg AA, Harris WH, Malchau H. Radiostereometric analysis comparison of wear of highly cross-linked polyethylene against 36- vs 28-mm femoral heads. J Arthroplasty. 2007 Sep;22(6 Suppl 2):125-9. Epub 2007 Jul 26. PMID:17823030 (Link to Abstract)

2. McCalden RW, Naudie DD, Yuan X, Bourne RB. Radiographic methods for the assessment of polyethylene wear after total hip arthroplasty. J Bone Joint Surg Am. 2005 Oct;87(10):2323-34. PMID:16203901 (Link to Abstract)

Question Authors:

John Badylak MD,

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(OBQ10.259) A design surgeon has created a new polyethlyene acetabular liner for total hip arthroplasty. Early clinical outcomes are comparable to conventional total hip arthroplasty. At 4 year follow-up, radioisometric analysis reveals 0.05 mm of annual wear in the surgeon's trial patients. Which of the following statements can be made from this data? Topic

Review Topic

1. Osteolysis and subsequent component loosening will be minimal if the wear rate continues
2. Osteolysis and subsequent component loosening will be greater than conventional hip arthroplasty if the wear rate continues
3. Predicting osteolysis and subsequent component loosening is not possible with this data
4. All total hip arthroplasties should use this new polyethylene
5. Patient satisfaction will be greater at 10 year follow up

PREFERRED RESPONSE ▶

DISCUSSION: Polyethylene wear rates have shown association with osteolysis and subsequent component loosening. Wear rates above 0.1 mm per year are at significant risk of osteolysis.

Dumbleton et al performed a meta-analysis of the literature concerning wear rates and osteolysis. They concluded that osteolysis was rarely observed when the wear rate was less than 0.1 mm per year.

Sakalkale et al reported on 10 year follow up of 60 total hips performed with a cementless, tapered, circumferentially coated femoral stem. They reported no osteolysis of the femoral component even though there was a high incidence of acetabular osteolysis.

Sochart et al reviewed 235 total hip arthroplasties performed by Charnley with 20 year follow-up. Osteolysis and revision was significantly associated with polyethylene wear rates. Average wear rates for hips that did not go on to revision was 0.09 mm per year compared to 0.19 mm per year for hips that were subsequently revised for loosening.

REFERENCES:

1. Dumbleton JH, Manley MT, Edidin AA. A literature review of the association between wear rate and osteolysis in total hip arthroplasty. J Arthroplasty. 2002 Aug;17(5):649-61 PMID:12168184 (Link to Abstract)

2. Sakalkale DP, Eng K, Hozack WJ, Rothman RH. Minimum 10-year results of a tapered cementless hip replacement. Clin Orthop Relat Res. 1999 May;(362):138-44. PMID:10335292 (Link to Abstract)

3. Sochart DH. Relationship of acetabular wear to osteolysis and loosening in total hip arthroplasty. Clin Orthop Relat Res. 1999 Jun;(363):135-50. PMID:10379315 (Link to Abstract)

Question Authors:

John Badylak MD,

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(OBQ09.180) Osteoprotegrin (OPG) binds to what structure to inhibit particle-induced osteolysis? Topic

Review Topic

1. RANK
2. RANK-ligand
3. OPG-receptor
4. CD7
5. CD10

PREFERRED RESPONSE ▶

DISCUSSION: Osteoprotegrin (OPG) binds to RANK ligand (answer 2) on the osteoblast to inhibit it from binding to RANK which are present on osteoclast-precursor cells. Normally, RANKL interacts with RANK to stimulate activation of osteoclasts. Jacobs et al present a nice review of the cellular and chemical mediators of osteolysis.

REFERENCES:

1. Einhorn TA, O’Keefe RJ, Buckwalter JA (eds): Orthopaedic Basic Science: Foundations of Clinical Practice, ed 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2007, pp 365-377

2. Jacobs JJ, Roebuck KA, Archibeck M, et al: Osteolysis: Basic science. Clin Orthop Relat Res 2001;393:71-77 PMID:11764373 (Link to Abstract)

Question Authors:

Paul D. Kim MD, John Badylak MD,

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(OBQ08.116) All of the following are risk factors for wear-related failure in total knee arthroplasty when using a polyethylene liner that underwent sterilization via gamma irradiation in air EXCEPT? Topic

Review Topic

1. Increasing shelf age of polyethylene liner
2. Younger age of patient
3. Male gender
4. Posterior cruciate retaining knee design
5. Use of a rough tibial baseplate

PREFERRED RESPONSE ▶

DISCUSSION: Increasing shelf age, younger age, male gender, and a rough tibial baseplate are all risk factors for wear-related failure in total knee arthroplasty when using a polyethylene liner. Posterior cruciate retaining knee design is not a documented risk factor.

Fehring et al reviewed 2091 TKA using the Press fit condylar system and noted that the 13-year survivorship for all patients was 82.6% with a 8.3% prevalence of wear-related failure. Cox hazards analysis revealed five variables that were correlated with wear-related failure: patient age, patient gender, polyethylene sheet vendor, polyethylene finishing method, and polyethylene shelf age. They were unable to identify one factor as the defining reason for these wear-related failures. They cautioned that these findings may only be specific to inserts that underwent sterilization via gamma irradiation in air.

Collier et al followed 365 TKA (PCL-retaining) for 5-10 yrs and noted that factors related to polyethylene insert osteolysis included advanced shelf age, sterilization method, and the material from which it was machined. Osteolysis was identified in 34% with an insert that had been gamma-irradiated in air and affixed to a rough baseplate surface, but only 9% when the insert had been gamma-irradiated in an inert gas or not irradiated at all and joined to a polished surface.

REFERENCES:

1. Fehring TK, Murphy JA, Hayes TD, Roberts DW, Pomeroy DL, Griffin WL. Factors influencing wear and osteolysis in press-fit condylar modular total knee replacements. Clin Orthop Relat Res. 2004 Nov;(428):40-50. PMID:15534517 (Link to Abstract)

2. Collier MB, Engh CA Jr, McAuley JP, Ginn SD, Engh GA. Osteolysis after total knee arthroplasty: influence of tibial baseplate surface finish and sterilization of polyethylene insert. Findings at five to ten years postoperatively. J Bone Joint Surg Am. 2005 Dec;87(12):2702-8. PMID:16322620 (Link to Abstract)

Question Authors:

Doug Nowak MD, Derek Moore, John Badylak MD,

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(OBQ08.245) Which type of inflammatory cell is involved in the biological response to metal-on-metal particulate debris? Topic

Review Topic

1. Neutrophil
2. Giant cell
3. Macrophage
4. Eosinophil
5. Lymphocyte

PREFERRED RESPONSE ▶

DISCUSSION: In metal-on-metal articulations, particulate wear debris stimulates lymphocytic invasion due to nanometer sized particles. Metal-on-metal prostheses generate less volumetric wear than metal-on-poly, and produce smaller, nanometer-sized wear particles. In metal-on-poly articulations, polyethylene wear debris stimulates a predominantly macrophage and fibroblast response, with giant cells also present. The size of polyethylene debris particles is in the micron range. Eosinophilic granuloma formation results from the clonal proliferation of Langerhans-type histiocytes; not related to wear debris. Heisel et al reviews the alternative bearing choices for total hip arthroplasty. Ceramic and metal on metal bearings have demonstrated reduced wear rates compared to metal on polyethylene. However, long term clinical results have yet to determine any clinical improvement. Davies et al evaluated periprosthetic tissue samples from 25 metal on metal total hip replacements and compared them to samples from metal on polyethylene total hips and osteoarthritic hips. A unique lymphocytic infiltrate was demonstrated in the metal on metal hips. The body's immune response to metallic debris is different than its response to osteoarthritis and polyethylene debris.

REFERENCES:

1. Heisel C, Silva, M, Schmalzried TP: Bearing surface options for total hip replacement in young patients. Instr Course Lect 2004;53:49-65 PMID:15116600 (Link to Abstract)

2. Davies AP, Willert HG, Campbell PA, et al: An unusual lymphocytic perivascular infiltration in tissues around contemporary metal-on-metal joint replacements. J Bone Joint Surg Am 2005;87:18-27 PMID:15634811 (Link to Abstract)

Question Authors:

John Badylak MD, Derek Moore, Dave Marcu MD,

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(OBQ07.11) Figure A is a photograph of a femoral head removed during revision of a ceramic on ceramic total hip arthroplasty. Which of the following is the most likely indication for this revision total hip arthroplasty? Topic

Review Topic

FIGURES: A

1. Prosthetic infection
2. Recurrent dislocations
3. Leg length discrepancy
4. Ceramic bearing fracture
5. Aseptic lymphocytic-vasculitis-associated lesion (ALVAL)

PREFERRED RESPONSE ▶

DISCUSSION: The markings on the femoral head have previously been described as resembling a pencil lead mark. Its presence indicates transfer of metal from the acetabular cup to the ceramic femoral head. This occurs during the component on component impingement and excursion that occurs during dislocation.

Kim et al conducted a retrieval analysis of 15 ceramic femoral heads that had metallic smearing as a result of dislocation. They found statistically significantly more femoral head surface roughness and increased polyethylene liner wear rates as the percentage of metallic smearing surface area increased. Scanning Electron Microscopic (SEM) evaluation commonly showed pits and scratches on the femoral head (Image A) and stereoscopic microscopy shows embedded metallic debris acting as a third body in the polyethyelene.

Illustrations: A

REFERENCES:

1. Kim YH, Ritchie A, Hardaker C. Surface roughness of ceramic femoral heads after in vivo transfer of metal: correlation to polyethylene wear. J Bone Joint Surg Am. 2005 Mar;87(3):577-82 PMID:15741625 (Link to Abstract)

Question Authors:

John Badylak MD, Ben Taylor MD,

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(OBQ07.145) Highly cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) liners used in total hip arthroplasty have which of the following characteristics compared to conventional UHMWPE liners? Topic

Review Topic

1. Increased average wear particle size
2. Increased resistance to abrasive wear
3. Increased number of wear particles generated
4. Increased resistance to fatigue crack propogation
5. Increased ductility

PREFERRED RESPONSE ▶

DISCUSSION: Highly cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) has improved resistance to adhesive and abrasive wear. Highly cross-linked UHMWPE is created by irradiating the polyethylene, which prompts free radicals from different polymer sections to combine to form chemical bonds between two polymer chains (cross-links). The amount of radiation exposure utilized to create these cross-links is between 5 and 10 Mrad with either gamma or electron beam radiation.

The Ries et al study showed that although cross-linking UHMWPE can reduce wear, they also demonstrate decreased mechanical properties (e.g. toughness, ductility, tensile strength, and fatigue strength) when compared with conventional UHMWPE.

McCalden et al peformed a Level 1 study of 100 patients randomized to highly cross-linked UHMWPE or conventional PE. The found that at an average of 6.8 years that the highly cross-linked polyethylene liner had significantly lower wear rates (as determined by femoral head penetration rates on radiographs).

Jacobs et al present a Level 5 review stating that highly cross-linked polyethylene has shown significantly decreased wear rates compared with conventional polyethylene in hip simulator studies. Additionally, they state that there have been no reports of clinically relevant osteolysis witnessed with highly crosslinked PE.

REFERENCES:

1. Ries MD, Pruitt L. Effect of cross-linking on the microstructure and mechanical properties of ultra-high molecular weight polyethylene. Clin Orthop Relat Res. 2005 Nov;440:149-56. PMID:16239799 (Link to Abstract)

2. McCalden RW, MacDonald SJ, Rorabeck CH, Bourne RB, Chess DG, Charron KD. Wear rate of highly cross-linked polyethylene in total hip arthroplasty. A randomized controlled trial. J Bone Joint Surg Am. 2009 Apr;91(4):773-82 PMID:19339560 (Link to Abstract)

3. Jacobs CA, Christensen CP, Greenwald AS, McKellop H. Clinical performance of highly cross-linked polyethylenes in total hip arthroplasty. J Bone Joint Surg Am. 2007 Dec;89(12):2779-86. PMID:18056513 (Link to Abstract)

Question Authors:

Michael Hughes MD, Guillem Lomas MD, Ben Taylor MD,

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(OBQ07.205) Highly cross-linked ultra high molecular weight polyethylene has which of the following characteristics? Topic

Review Topic

1. Improved ductility
2. Increased fracture toughness
3. Increases the elongation to break
4. Improved resistance to crack propagation
5. Improved wear resistance

PREFERRED RESPONSE ▶

DISCUSSION: Ultra high molecular weight polyethylene (UHMWPE) is a semicrystalline polymer that has been used for over four decades as a bearing surface in total joint replacements. The mechanical properties and wear properties of UHMWPE are of interest with respect to the in vivo performance of UHMWPE joint replacement components. The mechanical properties of the polymer are dependent on both its crystalline and amorphous phases. Altering either phase (i.e., changing overall crystallinity, crystalline morphology, or crosslinking the amorphous phase) can affect the mechanical behavior of the material.

Per the referenced article by Gencur et al, crosslinking improved wear resistance, but also was found to decrease the ability of UHMWPE to resist crack inception and propagation under cyclic loading. The findings also suggested that annealing as a post-irradiation treatment may be somewhat less detrimental to fracture crack propogation resistance of UHMWPE than remelting. Answers 1 through 4 are inversely false statements.

REFERENCES:

1. Gencur SJ, Rimnac CM, Kurtz SM. Fatigue crack propagation resistance of virgin and highly crosslinked, thermally treated ultra-high molecular weight polyethylene. Biomaterials. 2006 Mar;27(8):1550-7. PMID:16303175 (Link to Abstract)

Question Authors:

Ben Taylor MD, John Badylak MD,

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(OBQ07.236) Ultra-high-molecular-weight polyethylene (UHMWPE) particles have been associated with osteoclastogensis, a key component of osteolysis in total joint replacement. Which of the following accurately describes the expression of vascular endothelial gowth factor (VEGF) and receptor activator of nuclear factor kappa-B ligand (RANKL) during UHWMPE induced osteolysis? Topic

Review Topic

1. RANKL expression is decreased and VEGF is unchanged
2. VEGF expression is increased and RANKL is decreased
3. VEGF expression is increased and RANKL expression is unchanged
4. Expression of both VEGF and RANKL is increased
5. Expression of both VEGF and RANKL is decreased

PREFERRED RESPONSE ▶

DISCUSSION: RANKL, RANK, and VEGF are upregulated in any process that involves increased osteoclast activity.

Ren et al. found in a mouse model study that UHMWPE stimulation significantly increased VEGF, RANK, and RANKL gene expression. VEGF inhibitor was shown to reduce the UHMWPE-stimulated VEGF production. VEGF inhibitor also resulted in reduced RANK and RANKL gene transcripts. Thus, this study suggests that VEGF has a role in the regulation of RANK/RANKL-mediated osteoclastogenesis.

VEGF is also an important factor in angiogenesis in multiple tissues, including normal tissue (e.g. tendons) and several cancers.

Illustration A depicts the interaction of osteoblasts and osteoclasts (E=estrogen, P-C-P=bisphosphonates, CT=calcitonin). Illustration V is a video tutorial of RANK, RANK-L, and OPG and their role in postmenopausal osteoporosis.

Illustrations: A

REFERENCES:

1. Ren WP, Markel DC, Zhang R, Peng X, Wu B, Monica H, Wooley PH. Association between UHMWPE particle-induced inflammatory osteoclastogenesis and expression of RANKL, VEGF, and Flt-1 in vivo. Biomaterials. 2006 Oct;27(30):5161-9. PMID:16814378 (Link to Abstract)

Question Authors:

Derek Moore, Derek Moore, Patrick O'Donnell MD/PhD,

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(OBQ06.46) Figure A shows a ceramic head removed during a total hip revision. The component shows damage to the femoral head which was most likely caused by which of the following? Topic

Review Topic

FIGURES: A

1. Third body debris
2. Chronic infection
3. Impingement of the femoral stem neck on the acetabular socket
4. Lift-off separation of the femoral head during hip range of motion
5. Insertion of the head on the femoral stem at time of initial surgery

PREFERRED RESPONSE ▶

DISCUSSION: Ceramic-on-ceramic articulation has been an attractive alternative to metal-on-polyethylene articulation because it exhibits low-friction, load-tolerant behavior with satisfactory wear characteristics. Stripe-wear as found in Figure A is a distinct type of impingement from the classic impingement of the femoral head on the acetabular socket found in episodes of instability (ie. lift-off separation) during gait.

Yammamoto et al in a retrieval study of 3 ceramic bearings and found significant stripe scars/wear at the rim of the alumina, but not at the weight bearing portion of the head. They concluded that stripe wear is caused by the femoral head making contact with the rim of the socket when the head undergoes lift-off separation from the socket.

Manaka et al found that the locations of the stripes were similar in retrieved and simulator ceramic heads. However, the stripes from the simulator were narrower than the short-term retrievals and much narrower than some long-term retrievals.

REFERENCES:

1. Yamamoto T, Saito M, Ueno M, Hananouchi T, Tokugawa Y, Yonenobu K. Wear analysis of retrieved ceramic-on-ceramic articulations in total hip arthroplasty: Femoral head makes contact with the rim of the socket outside of the bearing surface. J Biomed Mater Res B Appl Biomater. 2005 May;73(2):301-7. PMID:15742373 (Link to Abstract)

2. Manaka M, Clarke IC, Yamamoto K, Shishido T, Gustafson A, Imakiire A. Stripe wear rates in alumina THR--comparison of microseparation simulator study with retrieved implants. J Biomed Mater Res B Appl Biomater. 2004 May 15;69(2):149-57. PMID:15116404 (Link to Abstract)

Question Authors:

Michael Hughes MD, Guillem Lomas MD, John Badylak MD,

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(OBQ06.220) Which of the following interventions reduces osteolysis around distal portion of the femoral stem when performing a total hip arthroplasty? Topic

Review Topic

1. Cementing the stem with a distal centralizer
2. Use of a circumferentially coated ingrowth stem
3. Use of a collared stem
4. Use of a long femoral stem
5. Ensuring that the stem fills the diaphysis of the femur

PREFERRED RESPONSE ▶

DISCUSSION: Osteolysis of the femur is caused by activation of macrophages by microscopic polyethylene particles within the "effective joint space", defined as any area where joint fluid can come into contact with bone. This can occur above the acetabular cup, through screw holes, and down the femoral shaft around the prosthetic stem. Ideally, with a cementless stem, both the proximal and metaphyseal femur are well filled by the prosthesis. Collared stems are used to augment poor calcar bone quality or bone loss.

Sinha et al showed in a retrospective review of 101 hips with cementless circumferentially coated femoral stems no distal femur osteolysis occurred, but 82% showed “evidence of proximal femur stress shielding”, though only 38% showed proximal femoral osteolysis.

REFERENCES:

1. Sinha RK, Dungy DS, Yeon HB. Primary total hip arthroplasty with a proximally porous-coated femoral stem. J Bone Joint Surg Am. 2004 Jun;86-A(6):1254-61. PMID:15173300 (Link to Abstract)

Question Authors:

John Badylak MD, Ben Taylor MD, Michael Hughes MD,

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Average 2.0 of 19 Ratings

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(OBQ05.63) Conventional polyethylene liner compared to the newer highly cross-linked polyethylene liners has all of the following characteristics EXCEPT? Topic

Review Topic

1. Higher steady-state femoral head penetration rate
2. Less resistant to adhesive wear
3. Generation of a smaller wear particle size
4. Increased fracture toughness
5. Increased tensile strength

PREFERRED RESPONSE ▶

DISCUSSION: All of those statements regarding conventional poly liners are true EXCEPT they generate larger (not smaller) wear particles than the highly cross-linked liners. It is the highly cross-linked liners that have been found to generate smaller wear particles.

Highly crossed-linked polyethylene in hip arthroplasty has been shown in multiple studies to be more wear resistant compared to conventional polyethylene, particularly in regards to adhesive wear. The highly cross-linked poly generates wear particles of a smaller size. In a randomized clinical study with 6.8 years follow-up, McCalden et al found that THA with highly cross-linked poly had a significantly lower femoral head penetration rate (0.003 mm/yr vs 0.051 mm/yr, p=0.025), which indicates less linear wear in the highly cross-linked poly. The disadvantage of highly cross-linked poly is that the cross-linking reduces its mechanical properties (e.g. decreased toughness, ductility, tensile strength, and fatigue strength) The Bradford reference looked at ex-planted liners and saw consistent evidence of early surface deformation and cracking; All explants exhibited some form of surface change, including surface cracking, abrasion, pitting, or scratching. The Jacobs paper makes the point that the cross-linked polys do seem to exhibit lower wear rates without significant osteolysis problems.

REFERENCES:

1. Bradford L, Baker DA, Graham J, Chawan A, Ries MD, Pruitt LA. Wear and surface cracking in early retrieved highly cross-linked polyethylene acetabular liners. J Bone Joint Surg Am. 2004 Jun;86-A(6):1271-82. PMID:15173302 (Link to Abstract)

2. Jacobs CA, Christensen CP, Greenwald AS, McKellop H. Clinical performance of highly cross-linked polyethylenes in total hip arthroplasty. J Bone Joint Surg Am. 2007 Dec;89(12):2779-86. PMID:18056513 (Link to Abstract)

3. McCalden RW, MacDonald SJ, Rorabeck CH, Bourne RB, Chess DG, Charron KD. Wear rate of highly cross-linked polyethylene in total hip arthroplasty. A randomized controlled trial. J Bone Joint Surg Am. 2009 Apr;91(4):773-82. PMID:19339560 (Link to Abstract)

Question Authors:

Patrick McCulloch MD, Guillem Lomas MD, Patrick McCulloch MD,

Please Rate Educational Value!

3.0

Average 3.0 of 22 Ratings

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(OBQ05.146) A 75-year-old man underwent total hip arthroplasty 10 years ago. He now reports mild groin pain which has been increasing lately. What is the most likely explanation for the finding in figure A indicated with the arrows? Topic

Review Topic

FIGURES: A

1. osteosarcoma
2. galvanic corrosion of the modular components
3. polyethlene wear particles tracking through the effective joint space
4. joint sepsis
5. occult fracture

PREFERRED RESPONSE ▶

DISCUSSION: Osteolysis of the pelvis is a common and well-recognized complication associated with total hip arthroplasty. Osteolysis affects sockets with and without cement, and has been attributed to the biologic reaction to wear debris. With well-fixed cementless sockets, an expansile pattern of osteolysis is usually seen. The radiographic appearance has a radiolucent area that starts at the implant-bone interface and expands into the cancellous bone away from the implant. This pattern of osteolysis can be explained with the concept of effective joint space. This concept states that joint fluid and wear particles will flow according to pressure gradients and follow the path of least resistance. There are concerns regarding screw holes and screws with cementless acetabular components and whether this may increase the incidence of osteolytic lesions. However, studies have found no direct correlation between presence of screw holes or screws and the incidence of osteolysis.

REFERENCES:

1. Chiang PP, Burke DW, Freiberg AA, Rubash HE. Osteolysis of the pelvis: evaluation and treatment.Clin Orthop Relat Res. 2003 Dec;(417):164-74. PMID:14646714 (Link to Abstract)

Question Authors:

Greg Galano MD, Derek Moore,

Please Rate Educational Value!

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(OBQ04.196) A 69-year-old female 16 years status post total knee arthroplasty complains of knee pain. A radiograph is provided in Figure A. Which of the following is true regarding the pathogenesis of the bony abnormality seen in the distal femur? Topic

Review Topic

FIGURES: A

1. It is related to the toughness of the polyethylene liner
2. It is more likely to occur with highly cross-linked polyethylene compared to conventional polyethylene
3. It is caused by macrophage activation by polyethylene particles
4. It is most frequently caused by infection
5. It is more common in a less constrained prothesis

PREFERRED RESPONSE ▶

DISCUSSION: The radiograph demonstrates polyethylene wear and osteolysis around the femoral component of a total knee replacement. Osteolysis is caused by macrophage activation from polyethylene particles. Ingham et al reviews the pathologic role of macrophages in osteolysis. Answer #1 is incorrect because toughness of the polyethylene is not related to wear rate, but does affect its overall mechanical strength. Answer #2 is incorrect because highly cross-linked polyethylene liners have lower wear rates compared to conventional polyethylene. Answer #5 is incorrect because wear rate is greater in a more constrained prosthesis. The listed reference by Huang concludes that there is an increased rate of osteolysis in mobile bearing TKA. This is a contradictory finding as mobile-bearing designs were created to decrease the stress and subsequent wear of the polyethylene

REFERENCES:

1. Huang CH, Ma HM, Liau JJ, Ho FY, Cheng CK. Osteolysis in failed total knee arthroplasty: a comparison of mobile-bearing and fixed-bearing knees. J Bone Joint Surg Am. 2002 Dec;84-A(12):2224-9. PMID:12473712 (Link to Abstract)

2. Ingham E, Fisher J. The role of macrophages in osteolysis of total joint replacement. Biomaterials. 2005 Apr;26(11):1271-86. PMID:15475057 (Link to Abstract)

Question Authors:

John Badylak MD, Derek Moore, Patrick McCulloch MD,

Please Rate Educational Value!

3.0

Average 3.0 of 9 Ratings

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ABOS II: Wear and Osteolysis

General - Oral Boards Review

7/29/2011

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Evidence & References Show References

Level of Evidence 1 (Randomized Control Trial)

McCalden RW, MacDonald SJ, Rorabeck CH, Bourne RB, Chess DG, Charron KD. Wear rate of highly cross-linked polyethylene in total hip arthroplasty. A randomized controlled trial. J Bone Joint Surg Am. 2009 Apr;91(4):773-82 PMID:19339560 (Link to Abstract)

Level of Evidence 4 (Case Series)

Davies AP, Willert HG, Campbell PA, et al: An unusual lymphocytic perivascular infiltration in tissues around contemporary metal-on-metal joint replacements. J Bone Joint Surg Am 2005;87:18-27 PMID:15634811 (Link to Abstract)
Sakalkale DP, Eng K, Hozack WJ, Rothman RH. Minimum 10-year results of a tapered cementless hip replacement. Clin Orthop Relat Res. 1999 May;(362):138-44. PMID:10335292 (Link to Abstract)
Sinha RK, Dungy DS, Yeon HB. Primary total hip arthroplasty with a proximally porous-coated femoral stem. J Bone Joint Surg Am. 2004 Jun;86-A(6):1254-61. PMID:15173300 (Link to Abstract)

Level of Evidence 5 and Other Journal Articles (includes Case Reports, Expert Opinions, Personal Observations, and Biomechanic Studies)

Heisel C, Silva, M, Schmalzried TP: Bearing surface options for total hip replacement in young patients. Instr Course Lect 2004;53:49-65 PMID:15116600 (Link to Abstract)
Amstutz HC, Campbell P, McKellop H, Schmalzreid TP, Gillespie WJ, Howie D, Jacobs J, Medley J, Merritt K. Metal on metal total hip replacement workshop consensus document. Clin Orthop Relat Res. 1996 Aug;(329 Suppl):S297-303. PMID:8769344 (Link to Abstract)
Archibeck MJ, Jacobs JJ, Roebuck KA, Glant TT. The basic science of periprosthetic osteolysis. Instr Course Lect. 2001;50:185-95. PMID:11372314 (Link to Abstract)
Brown TD, Bartel DL. Implant Wear Symposium 2007 Engineering Work Group. What design factors influence wear behavior at the bearing surfaces in total joint replacements? J Am Acad Orthop Surg. 2008;16 Suppl 1:S101-6. PMID:18612003 (Link to Abstract)
Dumbleton JH, Manley MT, Edidin AA. A literature review of the association between wear rate and osteolysis in total hip arthroplasty. J Arthroplasty. 2002 Aug;17(5):649-61 PMID:12168184 (Link to Abstract)
Gencur SJ, Rimnac CM, Kurtz SM. Fatigue crack propagation resistance of virgin and highly crosslinked, thermally treated ultra-high molecular weight polyethylene. Biomaterials. 2006 Mar;27(8):1550-7. PMID:16303175 (Link to Abstract)
Gonzalez MH, Mekhail AO. The failed total knee arthroplasty: evaluation and etiology. J Am Acad Orthop Surg. 2004 Nov-Dec;12(6):436-46. Review. PMID:15615509. (Link to Abstract)
Heisel C, Silva M, Schmalzried TP. Bearing surface options for total hip replacement in young patients. Instr Course Lect. 2004;53:49-65. Review. PMID:15116600 (Link to Abstract)
Jacobs CA, Christensen CP, Greenwald AS, McKellop H. Clinical performance of highly cross-linked polyethylenes in total hip arthroplasty. J Bone Joint Surg Am. 2007 Dec;89(12):2779-86. PMID:18056513 (Link to Abstract)
Ries MD, Pruitt L. Effect of cross-linking on the microstructure and mechanical properties of ultra-high molecular weight polyethylene. Clin Orthop Relat Res. 2005 Nov;440:149-56. PMID:16239799 (Link to Abstract)
von Schewelov TV, Carlsson A, Dahlberg L. Cross-linked N-telopeptide of type I collagen (NTx) in urine as a predictor of periprosthetic osteolysis. Journal of Orthopaedic Research. 2006; 24(7):1342-1348. PMID:16718682 (Link to Abstract)

Textbooks

Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012
AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009
Orthopaedic Knowledge Update 10, John M Flyn. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2011
Hoppenfeld SP. Surgical Exposures in Orthopaedics: The Anatomic Approach. Lipponcott, Williams, and Wilkins, Philadelphia, PA, Copyright 2009
Orthopaedic In-training Examination (OITE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Self-Assessment Examination (SAE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Abu-Amer Y, Clohisy JC. The biologic response to orthopaedic implants. In: Einhorn TA, O’Keefe RJ, Buckwalter JA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 3rd ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2007:365-377.
Zuscik MJ, Drissi MH, Chen D, Rosier RN. Molecular and cell biology in orthopaedics. In: Einhorn TA, O’Keefe RJ, Buckwalter JA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 3rd ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2007:3-23.

Undefined

Bradford L, Baker DA, Graham J, Chawan A, Ries MD, Pruitt LA. Wear and surface cracking in early retrieved highly cross-linked polyethylene acetabular liners. J Bone Joint Surg Am. 2004 Jun;86-A(6):1271-82. PMID:15173302 (Link to Abstract)
Bragdon CR, Greene ME, Freiberg AA, Harris WH, Malchau H. Radiostereometric analysis comparison of wear of highly cross-linked polyethylene against 36- vs 28-mm femoral heads. J Arthroplasty. 2007 Sep;22(6 Suppl 2):125-9. Epub 2007 Jul 26. PMID:17823030 (Link to Abstract)
Chiang PP, Burke DW, Freiberg AA, Rubash HE. Osteolysis of the pelvis: evaluation and treatment.Clin Orthop Relat Res. 2003 Dec;(417):164-74. PMID:14646714 (Link to Abstract)
Collier MB, Engh CA Jr, McAuley JP, Ginn SD, Engh GA. Osteolysis after total knee arthroplasty: influence of tibial baseplate surface finish and sterilization of polyethylene insert. Findings at five to ten years postoperatively. J Bone Joint Surg Am. 2005 Dec;87(12):2702-8. PMID:16322620 (Link to Abstract)
Einhorn TA, O’Keefe RJ, Buckwalter JA (eds): Orthopaedic Basic Science: Foundations of Clinical Practice, ed 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2007, pp 365-377
Fehring TK, Murphy JA, Hayes TD, Roberts DW, Pomeroy DL, Griffin WL. Factors influencing wear and osteolysis in press-fit condylar modular total knee replacements. Clin Orthop Relat Res. 2004 Nov;(428):40-50. PMID:15534517 (Link to Abstract)
Huang CH, Ma HM, Liau JJ, Ho FY, Cheng CK. Osteolysis in failed total knee arthroplasty: a comparison of mobile-bearing and fixed-bearing knees. J Bone Joint Surg Am. 2002 Dec;84-A(12):2224-9. PMID:12473712 (Link to Abstract)
Ingham E, Fisher J. The role of macrophages in osteolysis of total joint replacement. Biomaterials. 2005 Apr;26(11):1271-86. PMID:15475057 (Link to Abstract)
Jacobs CA, Christensen CP, Greenwald AS, McKellop H. Clinical performance of highly cross-linked polyethylenes in total hip arthroplasty. J Bone Joint Surg Am. 2007 Dec;89(12):2779-86. PMID:18056513 (Link to Abstract)
Jacobs JJ, Roebuck KA, Archibeck M, et al: Osteolysis: Basic science. Clin Orthop Relat Res 2001;393:71-77 PMID:11764373 (Link to Abstract)
Kim YH, Ritchie A, Hardaker C. Surface roughness of ceramic femoral heads after in vivo transfer of metal: correlation to polyethylene wear. J Bone Joint Surg Am. 2005 Mar;87(3):577-82 PMID:15741625 (Link to Abstract)
Manaka M, Clarke IC, Yamamoto K, Shishido T, Gustafson A, Imakiire A. Stripe wear rates in alumina THR--comparison of microseparation simulator study with retrieved implants. J Biomed Mater Res B Appl Biomater. 2004 May 15;69(2):149-57. PMID:15116404 (Link to Abstract)
McCalden RW, MacDonald SJ, Rorabeck CH, Bourne RB, Chess DG, Charron KD. Wear rate of highly cross-linked polyethylene in total hip arthroplasty. A randomized controlled trial. J Bone Joint Surg Am. 2009 Apr;91(4):773-82. PMID:19339560 (Link to Abstract)
McCalden RW, Naudie DD, Yuan X, Bourne RB. Radiographic methods for the assessment of polyethylene wear after total hip arthroplasty. J Bone Joint Surg Am. 2005 Oct;87(10):2323-34. PMID:16203901 (Link to Abstract)
McKellop HA. The lexicon of polyethylene wear in artificial joints. Biomaterials. 2007 Dec;28(34):5049-57 PMID:17706766 (Link to Abstract)
Ren WP, Markel DC, Zhang R, Peng X, Wu B, Monica H, Wooley PH. Association between UHMWPE particle-induced inflammatory osteoclastogenesis and expression of RANKL, VEGF, and Flt-1 in vivo. Biomaterials. 2006 Oct;27(30):5161-9. PMID:16814378 (Link to Abstract)
Sochart DH. Relationship of acetabular wear to osteolysis and loosening in total hip arthroplasty. Clin Orthop Relat Res. 1999 Jun;(363):135-50. PMID:10379315 (Link to Abstract)
Yamamoto T, Saito M, Ueno M, Hananouchi T, Tokugawa Y, Yonenobu K. Wear analysis of retrieved ceramic-on-ceramic articulations in total hip arthroplasty: Femoral head makes contact with the rim of the socket outside of the bearing surface. J Biomed Mater Res B Appl Biomater. 2005 May;73(2):301-7. PMID:15742373 (Link to Abstract)

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Wear & Osteolysis Basic Science

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