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- Callary, Stuart A., et al.
(author)
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Wear of a 5 Megarad Cross-linked Polyethylene Liner : A 6-year RSA Study
- 2013
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In: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 471:7, s. 2238-2244
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Journal article (peer-reviewed)abstract
- One cross-linked polyethylene (XLPE) liner is manufactured using a lower dose of radiation, 5 Mrad, which may result in less cross-linking. The reported in vivo wear rate of this XLPE liner in patients undergoing THA has varied, and has included some patients in each reported cohort who had greater than 0.1 mm/year of wear, which is an historical threshold for osteolysis. Previous studies have measured wear on plain radiographs, an approach that has limited sensitivity. We therefore measured the amount and direction of wear at 6 years using Radiostereometric analysis (RSA) in patients who had THAs that included a cross-linked polyethylene liner manufactured using 5 Mrad radiation. We prospectively reviewed wear in 30 patients who underwent primary THAs with the same design of cross-linked acetabular liner and a 28-mm articulation. Tantalum markers were inserted during surgery and all patients had RSA radiographic examinations at 1 week, 6 months, 1, 2, and 6 years postoperatively. The mean proximal, two-dimensional (2-D) and three-dimensional (3-D) wear rates calculated between 1 year and 6 years were 0.014, 0.014, and 0.018 mm/per year, respectively. The direction of the head penetration recorded between 1 week and 6 years was in a proximal direction for all patients, proximolateral for 16 of 24 patients, and proximomedial for eight of 24 patients. The proximal, 2-D and 3-D wear of a XLPE liner produced using 5 Mrad of radiation was low but measurable by RSA after 6 years. No patients had proximal 2-D or 3-D wear rates exceeding 0.1 mm/year. Further followup is needed to evaluate the effect of XLPE wear particles on the development of long-term osteolysis.
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| 3. |
- Campbell, David, et al.
(author)
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Case report : Cementless stem stabilization after intraoperative fracture: A radiostereometric analysis
- 2010
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In: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 468:3, s. 898-901
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Journal article (peer-reviewed)abstract
- We present the case of a patient with intraoperative femoral fracture during THA, which was repaired using cerclage fixation and insertion of an hydroxyapatite-coated cementless stem. The patient was evaluated postoperatively using radiostereometry during a 2-year course, and despite a large amount of subsidence and rotation, stabilization occurred and was maintained by 6 months. By evaluating the pattern of stem migration after intraoperative fracture, this case shows, even in the presence of instability, a successful clinical outcome can be achieved using an hydroxyapatite-coated cementless stem.
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| 4. |
- Dahl, Morten, et al.
(author)
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Stiffness and thickness of Fascia do not explain chronic exertional compartment syndrome
- 2011
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In: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 469:12, s. 3495-3500
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Journal article (peer-reviewed)abstract
- Background Chronic exertional compartment syndrome is diagnosed based on symptoms and elevated intramuscular pressure and often is treated with fasciotomy. However, what contributes to the increased intramuscular pressure remains unknown. Questions/purposes We investigated whether the stiffness or thickness of the muscle fascia could help explain the raised intramuscular pressure and thus the associated chronic compartment syndrome symptoms. Patients and Methods We performed plain radiography, bone scan, and intramuscular pressure measurement to diagnose chronic compartment syndrome and to exclude other disorders. Anterior tibialis muscle fascial biopsy specimens from six healthy individuals, 11 patients with chronic compartment syndrome, and 10 patients with diabetes mellitus and chronic compartment syndrome were obtained. Weight-normalized fascial stiffness was assessed mechanically in a microtensile machine, and fascial thickness was analyzed microscopically. Results Mean fascial stiffness did not differ between healthy individuals (0.120 N/mg/mm; SD, 0.77 N/mg/mm), patients with chronic compartment syndrome (0.070 N/mg/mm; SD, 0.052 N/mg/mm), and patients with chronic compartment syndrome and diabetes (0.097 N/mg/mm; SD, 0.073 N/mg/mm). Similarly, no differences in fascial thickness were present. There was a negative correlation between fascial stiffness and intramuscular pressure in the patients with chronic compartment syndrome and diabetes. Conclusions The lack of difference in fascial thickness and stiffness in patients with chronic compartment syndrome and patients with chronic compartment syndrome and diabetes compared with healthy individuals suggests structural and mechanical properties are unlikely to explain chronic compartment syndrome. To prevent chronic exertional compartment syndrome, it is necessary to address aspects other than the muscle fascia.
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| 10. |
- Gantelius, Stefan, et al.
(author)
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Higher Expression of Myosin Heavy Chain IIx in Wrist Flexors in Cerebral Palsy
- 2012
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In: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 470:5, s. 1272-1277
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Journal article (peer-reviewed)abstract
- BACKGROUND: Children with cerebral palsy (CP) use their paretic arm less than normal but have a relative overactivity of wrist flexors, causing an impairing flexed position of the wrist. Voluntary use of a muscle downregulates myosin heavy chain (MyHC) IIx, but it is unclear whether the relative overactivity of wrist flexors and extensors in children with CP affects MyHC expression compared to normal subjects. QUESTIONS/PURPOSES: We therefore asked whether MyHC expression composition differs in wrist flexors compared to extensors in children with CP and in controls and whether it is related to clinical findings. METHODS: We took muscle biopsies from wrist flexors and extensors during hand surgery in children with CP (n = 9) and during open reduction of forearm fractures in control children (n = 5). The expression of the MyHC I, IIa, and IIx isoforms were determined on silver-stained 6% SDS-PAGE. RESULTS: CP flexors showed a higher proportion of MyHC IIx (40%) than control flexors (16%) and CP extensors (20%). MyHC IIa isoform proportion was lower in CP flexors (27%) than in control flexors (46%) and in CP extensors (45%). MyHC I expression was lower in CP (36%) than in controls (46%) for wrist extensors only. CONCLUSIONS: Both the brain injury in CP and the different demands on flexors and extensors affect the expression of MyHCs. The higher amount of MyHC IIx in CP could be caused by a decreased voluntary use of the hemiplegic arm. CLINICAL RELEVANCE: More information on the structural difference between flexors and extensors in normal and spastic muscle could improve the understanding of strain of wrist extensors and possibly the development of flexion contractures in CP.
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| 13. |
- Hailer, Nils P, et al.
(author)
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High Metal Ion Levels After Use of the ASR™ Device Correlate With Development of Pseudotumors and T Cell Activation
- 2014
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In: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 472:3, s. 953-961
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Journal article (peer-reviewed)abstract
- BACKGROUNDPseudotumors and immunologic alterations are reported in patients with elevated metal ion levels after resurfacing arthroplasty of the hip. A direct association of increased cobalt and chromium concentrations with the development of pseudotumors has not been established.QUESTIONS/PURPOSE We hypothesized that (1) patients with higher blood cobalt and chromium concentrations are more likely to have pseudotumors develop, (2) elevated cobalt and chromium concentrations correlate with increased activation of defined T cell populations, and (3) elevated metal ion levels, small implant size, cup inclination angle, and patient age are risk factors for the development of pseudotumors.METHODSA single-surgeon cohort of 78 patients with 84 Articular Surface Replacement(®) implants was retrospectively investigated. Between 2006 and 2010, we performed 84 THAs using the Articular Surface Replacement(®) implant; this represented 2% (84/4950) of all primary hip replacements performed during that period. Of the procedures performed using this implant, we screened 77 patients (99%) at a mean of 43 months after surgery (range, 24-60 months). Seventy-one patients were investigated using ultrasound scanning, and cobalt and chromium concentrations in whole blood were determined by high-resolution inductively coupled plasma mass spectrometry. Differential analysis of lymphocyte subsets was performed by flow cytometry in 53 patients. Results of immunologic analyses were investigated separately for patients with and without pseudotumors. Pseudotumors were found in 25 hips (35%) and were more common in women than in men (p = 0.02). Multivariable regression analysis was performed to identify risk factors for the development of pseudotumors.RESULTSCobalt and chromium concentrations were greater in patients with pseudotumors than in those without (cobalt, median 8.3 versus median 1.0 μg/L, p < 0.001; chromium, median 5.9 versus median 1.3 μg/L, p < 0.001). The percentage of HLA-DR(+)CD4(+) T cells was greater in patients with pseudotumors than in those without (p = 0.03), and the proportion of this lymphocyte subtype was positively correlated with cobalt concentrations (r = 0.3, p = 0.02). Multivariable regression analysis indicated that increasing cobalt levels were associated with the development of pseudotumors (p < 0.001), and that patients with larger implants were less likely to have them develop (p = 0.04); age and cup inclination were not risk factors.CONCLUSIONSWe found a distinct association of elevated metal ion concentrations with the presence of pseudotumors and a correlation of increased cobalt concentrations with the proportion of activated T helper/regulator cells. Thus, the development of soft tissue masses after metal-on-metal arthroplasty could be accompanied by activation of T cells, indicating that this complication may be partly immunologically mediated. Further investigations of immunologic parameters in larger cohorts of patients with metal-on-metal arthroplasties are warranted.LEVEL OF EVIDENCELevel III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.
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| 14. |
- Johanson, Per-Erik, et al.
(author)
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Highly Crosslinked Polyethylene Does Not Reduce Aseptic Loosening in Cemented THA 10-year Findings of a Randomized Study.
- 2012
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In: Clinical orthopaedics and related research. - : Ovid Technologies (Wolters Kluwer Health). - 1528-1132 .- 0009-921X. ; 470:11, s. 3083-93
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Journal article (peer-reviewed)abstract
- Polyethylene (PE) wear particles are believed to cause aseptic loosening and thereby impair function in hip arthroplasty. Highly crosslinked polyethylene (XLPE) has low short- and medium-term wear rates. However, the long-term wear characteristics are unknown and it is unclear whether reduced wear particle burden improves function and survival of cemented hip arthroplasty.
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| 18. |
- Mohaddes, Maziar, 1974, et al.
(author)
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Method of Fixation Does Not Influence the Overall Risk of Rerevision in First-time Cup Revisions
- 2013
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In: Clinical orthopaedics and related research. - : Ovid Technologies (Wolters Kluwer Health). - 1528-1132 .- 0009-921X. ; 471:12, s. 3922-3931
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Journal article (peer-reviewed)abstract
- BACKGROUND: During the last two decades, uncemented fixation has been increasingly preferred worldwide during cup revision surgery. In Sweden, the number of uncemented cup revisions has been increasing during the last decade. However, it is unclear whether the risk of rerevision differs between cemented and uncemented cups. QUESTION/PURPOSES: We determined (1) the risk of rerevision after cemented and uncemented fixation; (2) the influence of concomitant stem revision on the risk of rerevision of the cup; (3) the difference in risk of rerevision of an uncemented cup revision compared with liner revision only; and (4) whether the surgical incision influenced the risk of rerevision. METHODS: Between 1979 and 2010, 19,342 first-time cup revisions were reported to the Swedish Hip Arthroplasty Register. From these, 749 were excluded (hip resurfacing, cases with tumor diagnoses, and missing data) leaving 18,593 (73% cemented) for further analysis. We used a Cox regression model adjusted for age, sex, primary diagnosis, method of fixation, concomitant stem revision, and cemented/uncemented fixation to assess risk of rerevision. RESULTS: The relative risk for rerevision for any reason did not differ between cemented and uncemented fixation (relative risk [RR], 0.94). If the stem was not revised at index revision, the risk of further cup revision increased twofold (RR, 1.91). Liner revisions were associated with a 70% increased risk for rerevision of the cup as a result of any reason and especially because of dislocation (RR, 2.94). The surgical incision did not influence the overall risk for rerevision (direct lateral/posterolateral: RR, 1.02) or the risk of rerevision resulting from dislocation (RR, 0.91). CONCLUSIONS: We found no difference in the overall risk of rerevision between cemented and uncemented fixation. Liner exchange had a higher risk for rerevision when compared with cases being rerevised with a new uncemented cup. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.
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| 19. |
- Nam, Denis, et al.
(author)
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Emerging Ideas: Instability-induced Periprosthetic Osteolysis Is Not Dependent on the Fibrous Tissue Interface
- 2013
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In: Clinical Orthopaedics and Related Research. - : Springer Verlag (Germany). - 0009-921X .- 1528-1132. ; 471:6, s. 1758-1762
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Journal article (peer-reviewed)abstract
- Stable initial fixation of a total joint arthroplasty implant is critical to avoid the risk of aseptic loosening and premature clinical failure. With implant motion, a fibrous tissue layer forms at the bone-implant interface, leading to implant migration and periprosthetic osteolysis. At the time of implant revision surgery, proresorptive signaling cytokines are expressed in the periimplant fibrous membrane. However, the exact role of this fibrous tissue in causing periprosthetic osteolysis attributable to instability remains unknown. less thanbrgreater than less thanbrgreater thanWe propose an alternative mechanism of periprosthetic osteolysis independent of the fibrous tissue layer, where pressurized fluid flow along the bone-implant interface activates mechanosensitive osteocytes in the periprosthetic bone, causing the release of proresorptive cytokines and subsequent osteoclast differentiation and osteolysis. less thanbrgreater than less thanbrgreater thanAn animal model for instability-induced osteolysis that mimics the periprosthetic bone-implant interface will be used. In this model, a fibrous tissue membrane is allowed to form in the periprosthetic zone, and pressurized fluid flow transmitted through this membrane reliably creates osteolytic lesions in the periprosthetic bone. In this study, half of the rats will have the fibrous tissue present, while the other half will not. We will determine whether the fibrous tissue membrane is essential for the release of proosteoclastic cytokines, leading to osteoclast differentiation and periprosthetic bone loss, by measuring the volume of bone resorption and presence of proresorptive cytokines at the bone-implant interface. less thanbrgreater than less thanbrgreater thanWe will determine whether the fibrous tissue membrane is crucial for osteoclastogenic signaling in the setting of periimplant osteolysis. In the future, this will allow us to test therapeutic interventions, such as specific cytokine inhibitors or alterations in implant design, which may translate into new, clinically relevant strategies to prevent osteolysis.
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| 20. |
- Riad, Jacques, et al.
(author)
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Are Muscle Volume Differences Related to Concentric Muscle Work During Walking in Spastic Hemiplegic Cerebral Palsy?
- 2012
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In: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 470:5, s. 1278-1285
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Journal article (peer-reviewed)abstract
- Background: Individuals with spastic hemiplegic cerebral palsy are typically high functioning and walk without assistive devices. The involved limb is usually smaller and shorter, although it is not clear whether the difference in muscle volume has an impact on walking capacity. Questions/purposes: We determined the volume of muscles important for propulsion and related that volume to concentric muscle work during walking on the hemiplegic and noninvolved sides in patients with cerebral palsy. Patients and Methods: We studied 46 patients (mean age, 17.6 years; range, 13-24 years) with spastic hemiplegic cerebral palsy. We assessed muscle volume using MRI and concentric muscle work in the sagittal plane from the hip, knee, and ankle using three-dimensional gait analysis. Patients were classified by Winters' criteria to assess the involvement of cerebral palsy and movement pattern during walking. Results: On the hemiplegic side, muscles were smaller, except for the gracilis muscle, and concentric muscle work from the ankle plantar flexors, knee extensors, and hip flexors and extensors was lower compared to the noninvolved side. Hip extensor work was higher on the hemiplegic and the noninvolved sides compared to a control group of 14 subjects without cerebral palsy. Hemiplegic to noninvolved volume ratios correlated with work ratios (r = 0.40-0.66). The Winters classification and previous calf muscle surgery predicted work ratios. Conclusions: Our observations of smaller muscles on the hemiplegic side and changes in muscle work on both sides can help us distinguish between primary deviations that may potentially be treatable and compensatory mechanisms that should not be treated.
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| 21. |
- Rodby-Bousquet, Elisabet, et al.
(author)
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Better Walking Performance in Older Children With Cerebral Palsy
- 2012
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In: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 470:5, s. 1286-1293
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Journal article (peer-reviewed)abstract
- Background: Children with cerebral palsy (CP) often walk with a slower speed and a higher energy cost. Their walking performance and choice of mobility method may vary in different environments. Independent mobility is important for activity and participation. Questions/purposes: We described walking performance at different distances and environments in relation to gross motor function, CP subtype, and age. Patients and Methods: We performed a cross-sectional study including all 562 children 3 to 18 years with CP living in southern Sweden during 2008. Data were extracted from a Swedish CP register and healthcare program. The Functional Mobility Scale (FMS) was used for rating mobility at home (5 m), at school (50 m), and in the community (500 m). The FMS scores were analyzed in relation to Gross Motor Function Classification System (GMFCS) level, CP subtype, and age. Results: In this population, 57% to 63% walked 5 to 500 m without walking aids and 4% to 8% used walking aids. We found a correlation between FMS and GMFCS. The walking performance varied between the subtypes from 96% to 98% in those with spastic unilateral CP to 16% to 24% in children with dyskinetic CP. An increased proportion of children walked independently on all surfaces in each successive age group. Conclusions: The overall walking performance increased up to 7 years of age, but the proportion of children walking independently on uneven surfaces was incrementally higher in each age group up to 18 years. The ability to walk on uneven surfaces is important for achieving independent walking in the community.
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| 22. |
- Tillander, Jonatan, 1975, et al.
(author)
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Osseointegrated titanium implants for limb prostheses attachments: infectious complications.
- 2010
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In: Clinical orthopaedics and related research. - : Ovid Technologies (Wolters Kluwer Health). - 1528-1132 .- 0009-921X. ; 468:10, s. 2781-2788
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Journal article (peer-reviewed)abstract
- BACKGROUND: The concept of osseointegration involves direct contact between titanium implant and bone. This transcutaneous prosthetic system for amputees is intended to assure stable long-term fixation. Most metal transcutaneous implants have failed, primarily owing to infection. QUESTIONS/PURPOSES: We determined the frequency and describe the presentation of infectious complications with this novel method. We also evaluated the bacterial flora at the skin-penetration area and its relation to the development of local and implant-related infection. PATIENTS AND METHODS: We prospectively followed 39 patients with arm and leg amputations fitted with transcutaneous osseointegrated titanium implants a mean of 56 months earlier (range, 132-133 months). There were 33 femoral, one tibial, four ulnar, four radial, and three humeral implants. Patients were selected during a 6-month period in 2005 and identically reevaluated after 3 years. Implant infection was defined as definite, probable, or possible based on clinical, radiologic, and microbiologic evidence. RESULTS: The frequency of implant infection was 5% at inclusion and 18% at followup. One patient with infection recovered owing to antibiotic treatment and another patient had the implant removed. Most implant infections had low infectious activity, and in five of the seven patients with infections, prosthetic use was not affected. The most common bacteria in superficial and deep cultures were Staphylococcus aureus and coagulase-negative staphylococci. CONCLUSIONS: Despite frequent colonization around the skin-implant interface by potentially virulent bacteria such as Staphylococcus aureus and bacteria associated with biomedical device infections such as coagulase-negative staphylococci, this titanium implant system for bone-anchored prostheses caused few infections leading to disability or implant removal. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
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| 23. |
- Tsikandylakis, Georgios, et al.
(author)
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Implant Survival, Adverse Events, and Bone Remodeling of Osseointegrated Percutaneous Implants for Transhumeral Amputees.
- 2014
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In: Clinical Orthopaedics and Related Research. - 0009-921X .- 1528-1132. ; 472:10, s. 2947-56
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Journal article (peer-reviewed)abstract
- Background: Osseointegrated percutaneous implants provide direct anchorage of the limb prosthesis to the residual limb. These implants have been used for the rehabilitation of transhumeral amputees in Sweden since 1995 using a two-stage surgical approach with a 6-month interval between the stages, but results on implant survival, adverse events, and radiologic signs of osseointegration and adaptive bone remodeling in transhumeral amputees treated with this method are still lacking. Questions/purposes: This study reports on 2- and 5-year implant survival, adverse events, and radiologic signs of osseointegration and bone remodeling in transhumeral amputees treated with osseointegrated prostheses. Methods: Between 1995 and 2010, we performed 18 primary osseointegrated percutaneous implants and two implant revisions in 18 transhumeral amputees; of those, 16 patients were available for followup at a minimum of 2 years (median, 8 years; range, 2-19 years). These include all transhumeral amputees who have received osseointegrated prostheses and represented approximately 20% of the all transhumeral amputees we evaluated for potential osseointegration during that time; general indications for this approach included transhumeral amputation resulting from trauma or tumor, inability to wear or severe problems wearing a conventional socket prosthesis, eg, very short residual limb, and compliant patients. Medical charts and plain radiographs were retrospectively evaluated. Results: The 2- and 5-year implant survival rates were 83% and 80%, respectively. Two primary and one revised implant failed and were removed because of early loosening. A fourth implant was partially removed because of ipsilateral shoulder osteoarthritis and subsequent arthrodesis. The most common adverse event was superficial infection of the skin penetration site (15 infections in five patients) followed by skin reactions of the skin penetration site (eight), incomplete fracture at the first surgery (eight), defective bony canal at the second surgery (three), avascular skin flap necrosis (three), and one deep implant infection. The most common radiologic finding was proximal trabecular buttressing (10 of 20 implants) followed by endosteal bone resorption and cancellization (seven of 20), cortical thinning (five of 20), and distal bone resorption (three of 20). Conclusions: The implant system presented a survivorship of 83% at 5 years and a 38% 5-year incidence of infectious complications related to the skin penetration site that were easily managed with nonoperative treatment, which make it a potentially attractive alternative to conventional socket arm prostheses. Osseointegrated arm prostheses have so far only been used in transhumeral amputations resulting from either trauma or tumor. Their use has not been tested and is therefore not recommended in transhumeral amputations resulting from vascular disease. This method could theoretically be superior to socket prostheses, especially in transhumeral amputees with very short residual humerus in which the suspension of a conventional prosthesis is difficult. Comparative studies are needed to support its potential superiority. Moreover, the radiological findings in this study need to be followed over time because some of them are of uncertain long-term clinical relevance
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