In the mid to late 1990s, to sterilize UHMWPE bearings, manufacturers changed from gamma-irradiation-in-air (gamma-air) sterilization, which initiated oxidation leading to bearing fatigue, to gamma-irradiation sterilization in an inert environment (gamma-inert). The change to gamma-inert sterilization reportedly prevented shelf oxidation before implantation but not in vivo oxidation.
Surface damage of the tibial polyethylene insert in TKA is thought to diminish with increasing conformity, based on computed lower contact stresses. Added constraint from higher conformity may, however, result in greater forces in vivo.
In Vivo Oxidation and Surface Damage in Retrieved Ethylene Oxide-sterilized Total Knee Arthroplasties
Gas sterilization (eg, ethylene oxide [EtO] and gas plasma) was introduced for polyethylene to reduce oxidation due to free radicals occurring during radiation sterilization. Recently, oxidation has been observed in polyethylenes with undetectable levels of free radicals, which were expected to be oxidatively stable. It is unclear whether in vivo oxidation will occur in unirradiated inserts sterilized with EtO.
Knowledge about factors leading to failure of posterior dynamic stabilization implants is essential to design future implants and establish surgical indications. Therefore, we analyzed an implant for single-level or hybrid configuration (adjacent to spondylodesis), which was recalled due to high failure rates.
To accurately quantify polyethylene wear in retrieved arthroplasty components, the original geometry of the component must be estimated accurately using a reference geometry such as a computer-aided design (CAD) model or a never-implanted insert. However, differences may exist between the CAD model and manufactured inserts resulting from manufacturing tolerances.
Posterior Cruciate Mechanoreceptors in Osteoarthritic and Cruciate-retaining TKA Retrievals: A Pilot Study
Although normal cruciate ligaments and those in patients with osteoarthritic (OA) knees contain mechanoreceptors, it is unclear whether they are present after functioning in a cruciate-retaining total knee arthroplasty (TKA).
Polyethylene wear is often cited as the cause of failure of TKA. Rotating platform (RP) knees show notable surface damage on the rotating surface raising concerns about increased wear compared to fixed bearing inserts.
Cementless fixation remains controversial in TKA due to the challenge of achieving consistent skeletal attachment. Factors predicting durable fixation are not clearly understood, but we presumed bone ingrowth could be enhanced by the quantity of host bone and application of autograft bone chips.
Failure of TKA from aseptic loosening is a growing concern, as TKA is performed with increasing frequency. Loosening is multifactorial and may be associated with elevated inflammatory cytokines in addition to biomechanical failure.
While modular femoral heads have been used in THA for decades, a recent innovation is a second neck-stem taper junction. Clinical advantages include intraoperative adjustment of leg length, femoral anteversion, and easier revision, all providing flexibility to the surgeon; however, there have been reports of catastrophic fracture, cold welding, and corrosion and fretting of the modular junction.
Pseudotumors are sterile inflammatory lesions found in the soft tissues surrounding metal-on-metal (MOM) and metal-on-polyethylene hip arthroplasties. In patients with MOM hip arthroplasties, pseudotumors are thought to represent an adverse reaction to metal wear debris. However, the pathogenesis of these lesions remains unclear. Currently, there is inconsistent evidence regarding the influence of adverse cup position and increased wear in the formation of pseudotumors.
Failure rates of constrained cups for treating recurrent dislocation in revision THA range from 40% to 100%. Although constrained liners are intended to stabilize the hip by mechanically preventing dislocation, the resulting loss of range of motion may lead to impingement and, ultimately, implant failure.
Before the US Patient Protection and Affordable Care Act of 2010, there were documented insurance-based disparities in access to orthopaedic surgeons and care of orthopaedic conditions. While Massachusetts passed healthcare reform in 2007 with many similar provisions, it is unknown whether the disparities were present during the period of the law’s enactment.
Nonsurgical management of de Quervain’s tenosynovitis often includes corticosteroid injections. If the injection does not enter the compartment, or all subcompartments, response to the injection is variable. To ensure proper location of injections we evaluated the role of ultrasound.
The use of dual-mobility cups has increased because of a low rate of dislocations combined with a 96% 15-year survival rate. However, late cup migrations have been attributed to their fixation (tripod - exact fit with two pegs and one extraacetabular screw) and the absence of porous coating. In a second-generation device, the designs were modified to achieve press-fit fixation and a layer of titanium beads was sintered on stainless steel cups.
Proximal cementless fixation using anatomic stems reportedly increases femoral fit and avoids stress-shielding. However, thigh pain was reported with the early stem designs. Therefore, a new anatomic cementless stem design was based on an average three-dimensional metaphyseal femoral shape. However, it is unclear whether this stem reduces the incidence of thigh pain.
Currently, plain radiographs and MRI are the standard imaging modalities used for diagnosing femoroacetabular impingement (FAI) and preoperative planning for arthroscopic treatment of FAI. The value of three-dimensional (3D) CT for these purposes is unclear.
Periarticular infiltration of local anesthetic, NSAIDs, and adrenaline have been reported to reduce postoperative pain, improve mobility, and reduce hospital stay for patients having THAs, but available studies have not determined whether local anesthetic infiltration alone achieves similar improvements.
Wide variation in procedure utilization suggests that surgical indications might not be rigorously defined. An alternative explanation is that surgical outcomes are valued differently across groups. When a patient, using the information provided by the surgeon, places high value on successful results or is indifferent to the costs of ineffective treatment, the treatment threshold is lower and more surgery will be chosen.
Does Primary or Secondary Chondrocalcinosis Influence Long-term Survivorship of Unicompartmental Arthroplasty?
Coexistence of degenerative arthritis and calcium pyrophosphate dihydrate (CPPD) crystals (or radiological chondrocalcinosis) with osteoarthritis (OA) of the knees is frequent at the time of arthroplasty. Several studies suggest more rapid clinical and radiographic progression with CPPD than with OA alone. However, it is unclear whether chondrocalcinosis predisposes to higher risks of progression of arthritis in other compartments.
Total ankle arthroplasty (TAA) is an evolving treatment for end-stage ankle arthritis, however, there is controversy regarding its longevity.
Gowers’ sign is a screening test for muscle weakness, typically seen in Duchenne muscular dystrophy but also seen in numerous other conditions. The mildest presentations and the variations of Gowers’ sign are poorly described in the literature but are important to recognize to help with early diagnosis of a neuromuscular problem.
Does Short-term Application of an Ilizarov Frame with Transfixion Pins Correct Relapsed Clubfoot in Children?
Treatment of relapsed clubfoot after soft tissue release in children is difficult because of the high recurrence rate and related complications. Even though the Ilizarov method is used for soft tissue distraction, there is a high incidence of recurrence after removal of the Ilizarov frame owing to previous contracture of soft tissue and a skin scar.
Does Limb-salvage Surgery Offer Patients Better Quality of Life and Functional Capacity than Amputation?
Patients with aggressive lower extremity musculoskeletal tumors may be candidates for either above-knee amputation or limb-salvage surgery. However, the subjective and objective benefits of limb-salvage surgery compared with amputation are not fully clear.
The pelvis is an infrequent site of osteosarcoma and treatment requires surgery plus systemic chemotherapy. Poor survival has been reported, but has not been confirmed previously by the Children’s Oncology Group (COG). In addition, survival of patients with pelvic osteosarcomas has not been compared directly with that of patients with nonpelvic disease treated on the same clinical trials.
A novel calcium sulfate–calcium phosphate composite injectable bone graft substitute has been approved by the FDA for filling bone defects in a nonweightbearing application based on preclinical studies. Its utility has not been documented in the literature.
One-Screw Fixation Provides Similar Stability to That of Two-Screw Fixation for Type II Dens Fractures
Anterior screw fixation has been widely adopted for the treatment of Type II dens fractures. However, there is still controversy regarding whether one- or two-screw fixation is more appropriate.
The diagnosis of displacement in scaphoid fractures is notorious for poor interobserver reliability.
Surgical Treatment of Neer Group VI Proximal Humeral Fractures: Retrospective Comparison of PHILOS® and Hemiarthroplasty
Neer Group VI proximal humeral fractures often are related to persistent disability despite surgical treatment. We retrospectively compared the outcome after open reduction and internal fixation with the PHILOSplate or primary hemiarthroplasty in patients with Neer Group VI fractures focusing on complications, shoulder function, health-related quality of life (SF-36), and potential risk factors for complications.
Cartilage defects are created on intraarticular osteochondral fragments at the entrance holes of fixation devices when these fragments are fixed to the original sites. Conventional fixation devices hinder repair of these defects and there is a latent risk of secondary osteoarthritis. We therefore developed a novel fixation device system consisting of bone screws made of cortical bone for osteochondral fragments to improve repair of these surface defects.