Claire E. Robbins

Squeaking in Total Hip Replacement: No Cause for Concern

Traditional total hip arthroplasty (THA) using metalon-polyethylene bearings has been established as a reliable procedure, but polyethylene wear and wear debris–associated osteolysis are among the most frequent reasons for revision.1 Hard-bearing-surface THAs with improved tribological properties have been introduced to decrease wear and wear debris–induced osteolysis. Among the hardbearing alternatives, alumina ceramic-on-ceramic bearings have consistently shown low wear and biological reactivity to wear particles. Clinically, ceramic-on-ceramic hip arthroplasties with modern metal-backed alumina cups have demonstrated excellent clinical outcomes with low revision rates,2,3 with complications such as acetabular liner, femoral head fractures, or chipping occurring rarely.4 Curiously, after more than 30 years of clinical experience with alumina ceramic-on-ceramic bearings worldwide and with 2 closely studied longterm FDA studies in the United States,2,3 a new phenomenon of frequent, clinically reproducible squeaking was reported, primarily beginning in 2006. Further, these reports were authored by surgeons who had little, if any, experience with alumina ceramic-on-ceramic bearings during the IDE study period from 1997 to 2003. Inevitably, many theories were proposed to explain this phenomen, including mismatched ceramic bearings diameters,5 edge loading due to acetabular component malpositioning,6 disruption of fl uid fi lm lubrication with stripe wear,7 microseparation and subluxation of the femoral head,7 the use of short necks,8 and wear debris from metal-on-metal impingement in implants.9 Ultimately though, one fundamental question has remained: Why, after years of successfully using ceramic-on-ceramic THA, did this phenomenon of squeaking suddenly become frequently noted by a subset of surgeons, particularly practicing in the Unitied States? The goal of this study was to use our clinical experience with two FDA IDE studies2,3 during a period of more than 10 years to improve our understanding of this squeaking phenomenon.

Use of a hydroxyapatite-coated stem in patients with Dorr Type C femoral bone.

Type C bone, as described by Dorr, exhibits both cellular and structural compromise, which presents a challenge for fixation of a total hip arthroplasty (THA). We evaluated the performance of the Omnifit® HA stem, a hydroxyapatite-coated titanium alloy stem, by retrospectively reviewing the clinical and radiographic data of 15 patients with femoral Type C bone who received the stem during primary THA between 1991 and 1994. The patients were followed a minimum of 9 years (mean, 11.5 years; range, 9-14 years). The average age at surgery was 54 years and the average body mass index was 28. Eight of the patients were men. The median Harris hip score was 94.5 points. Radiographically, two independent reviewers identified all patients as Type C bone. The average canal to calcar isthmus ratio was 0.74 (range, 0.65-0.95). At most recent followup, four patients demonstrated proximal osteolysis. Using plain radiography we detected no patients with distal osteolysis or subsidence. At 9 to 14 years, the stem has performed well in a selected series of patients with poor bone quality and the outcomes compare favorably with previously reported findings using this design of stem in other bone types. These results support the decision to use a hydroxyapatite-coated stem in patients with Type C bone.Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Complications of Femoral Nerve Blockade in Total Knee Arthroplasty and Strategies to Reduce Patient Risk

Femoral nerve catheters are widely used for analgesia in total knee arthroplasty. Although evidence suggests that catheters improve pain control and may facilitate short-term rehabilitation, few reports exist regarding their complications. This case series explores the experience of femoral nerve catheter use at high-volume orthopedic specialty hospitals. Serious complications including compartment syndrome, periprosthetic fracture, and vascular injury are reported. The authors support femoral nerve catheter use with appropriate precautions taken to reduce risk of patient falls, vascular injury, and wrong-site surgery.

Corrosion and Adverse Local Tissue Reaction in One Type of Modular Neck Stem

Modular neck stems allow for optimization of joint biomechanics by restoring anteversion, offset, and limb length. A potential disadvantage is the generation of metal ions from fretting and crevice corrosion. We identified 118 total hip arthroplasty implanted with one type of dual-modular femoral component. Thirty-six required revision due to adverse local tissue reaction. Multivariate analysis isolated females and low offset necks as risk factors for failure. Kaplan-Meir analysis revealed small stem sizes failed at a higher rate during early follow-up period. Although the cobalt/chrome levels were higher in the failed group, these tests had low diagnostic accuracy for ALTR, while MRI scan was more sensitive. We conclude that the complications related to the use of dual modular stems of this design outweigh the potential benefits.

Total Joint Replacement in the Elderly Patient

Osteoarthritis of the hip and knee is extremely common in the growing elderly population. Total joint replacement (TJR) of the hip and knee are extremely effective procedures, resulting in decreased pain and improved function and quality of life in patients of all age groups including the elderly. The prevalence and use of TJR is increasing at a significant rate, therefore increased awareness of perioperative issues following TJR among health care providers is of paramount importance. Although elderly patients may be slightly more susceptible to perioperative complications, long-term success rates remain high, and careful perioperative monitoring and preventative measures have resulted in high rates of patient safety and few adverse outcomes in the elderly.

Femoral Head Dislodgement Complicating Use of a Dual Mobility Prosthesis for Recurrent Instability

The dual mobility cup is an unconstrained tripolar configuration newly introduced to the United States in February 2011. The dual mobility construct allows for a larger femoral head to improve motion and minimize the risk of dislocation. We present a case of a patient who received the dual mobility cup for the treatment of recurrent dislocation following total hip arthroplasty. Early in the patients postoperative course, the implant failed at the articulation between the larger outer polyethylene head and inner smaller metal femoral head following an attempt at closed reduction. This implant specific complication has not been reported in the North American literature.

Pharmacologic Pain Management Before and After Total Joint Replacement of the Hip and Knee

There are many effective treatment measures for OA of the hip or knee, with varying degrees of effectiveness. Nonoperative measures include patient education, physical therapy, activity modification, weight loss, and medications. Pharmacologic strategies include acetaminophen, NSAIDs, injections of cortisone or viscosupplementation, and, less commonly, tramadol or other pain relievers. In patients who may be candidates for TJR, narcotic medications should be avoided to preserve their benefits for the postoperative period. Over the past 20 years, multimodal pain management has been beneficial to the patient undergoing TJR surgery. Studies have shown this form of pain management decreases postoperative opioid consumption and the related adverse effects. Research is warranted in the areas of postoperative pain scores and patient satisfaction as institutional multimodal protocols continue to evolve.

Effect of Preoperative Exercise on Postoperative Mobility in Obese Total Joint Replacement Patients

There has been a significant increase in obesity in the United States over the past 20 years. Reports in the literature identify the association of obesity-related osteoarthritis and the likelihood of future total hip arthroplasty (THA) and total knee arthroplasty (TKA) in this patient population. However, little is known about the effect of preoperative exercise on immediate postoperative mobility and discharge disposition in obese total joint replacement patients. The purpose of this study was to examine the effect of preoperative exercise in the obese total joint replacement patient on early postoperative mobility and discharge disposition. We retrospectively reviewed a consecutive series of patients with a body mass index (BMI) ≥30 kg/m(2) who underwent primary total joint replacement surgery from June 2005 through October 2005 at 1 institution. Two hundred seven patients met the inclusion criteria. Sixty-five patients performed self-reported preoperative exercise, defined as physical activity deemed above and beyond that of activities of daily living. Fewer exercise patients, 6.8%, required the assistance of ≥2 caregivers for mobility on postoperative day 1 vs 17.4% for nonexercisers. Fifty-four percent of patients participating in preoperative exercise were discharged home vs 46% who did not participate in exercise. A preoperative exercise program can improve postoperative functional mobility and increase the likelihood of discharge home in total joint replacement patients with a BMI of ≥30 kg/m(2).

Total Hip Intraoperative Femur Fracture: Do the Design Enhancements of a Second Generation Tapered Wedge Stem Reduce the Incidence?

BACKGROUND Intraoperative femur fracture (IFF) is a well-known complication in primary uncemented total hip arthroplasty (THA). Variations in implant instrumentation design and operative technique may influence the risk of IFF. This study investigates IFF between a standard uncemented tapered-wedge femoral stem and its second-generation successor with the following design changes: size-specific medial curvature, proportional incremental stem growth, modest reduction in stem length, and distal lateral relief. METHODS A single experienced surgeons patient database was retrospectively queried for IFF occurring during primary uncemented THA using a standard tapered-wedge femoral stem system or a second-generation stem. All procedures were performed using soft tissue preserving anatomic capsule repair and posterior approach. The primary outcome measure was IFF. A z-test of proportions was performed to determine significant difference between the 2 stems with respect to IFF. Patient demographics, Dorr classification, and implant characteristics were also examined. RESULTS Forty-one of 1510 patients (2.72%) who received a standard tapered-wedge femoral stem sustained an IFF, whereas 5 of 800 patients (0.63%) using the second-generation stem incurred an IFF. No other significant associations were found. CONCLUSION A standard tapered-wedge femoral stem instrumentation system resulted in greater than 4 times higher incidence of IFF than its second-generation successor used for primary uncemented THA. Identifying risk factors for IFF is necessary to facilitate implant system improvements and thus maximize patient outcomes.

TKA After Clamshell Osteotomy for Femoral Diaphyseal Malunion

Proper component positioning is essential for successful total knee arthroplasty (TKA). Femoral component positioning presents a technical challenge when significant femoral deformity is present. Most commonly, an intramedullary guide is used to make an accurate distal femoral cut. However, in the presence of a significant femoral deformity, this is not a viable option.The use of clamshell osteotomy to restore anatomic alignment in patients with complex femoral diaphyseal deformity is described in the literature. This article describes a case of a patient who underwent staged TKA after clamshell osteotomy and retrograde femoral nailing to correct femoral diaphyseal malunion. The retrograde intramedullary nail was retained and used as an intramedullary guide, allowing for TKA in a routine manner. Using an intramedullary nail as an alignment guide may be more accurate than using extramedullary alignment and may avoid the increased surgical time and potential pin-site stress risers of navigation. It is a simple, effective way to treat complicated diaphyseal femoral deformities in the face of posttraumatic knee arthritis. Further study of this technique with longer follow-up and multiple surgeons is necessary to validate this treatment algorithm.