Faculty Bibliography

BACKGROUND:While innovation drives advancement, it is not immune to failure. Previously, we reported a corrosion-related revision rate of 28% (23 of 81 total hip arthroplasties) among patients who received the Rejuvenate modular-neck stem implant with short-term follow-up. Because we observed a dramatic interval failure rate after our initial report, we undertook this study. METHODS:We prospectively followed a cohort of patients who had undergone implantation of the Rejuvenate modular-neck stem, as previously reported. At a minimum of 3 years of follow-up (range, 3.0 to 5.5 years), 73 hips in 63 patients (90% of the original group) were available for analysis. The mean serum cobalt and chromium ion levels were obtained preoperatively and postoperatively. Elevated serum cobalt ion levels (>4 μg/L), pain, or abnormal magnetic resonance imaging (MRI) findings were indications for revision surgery. Patient factors and serum metal ion levels were correlated to revision surgery. Additionally, post-revision serum cobalt and chromium ion level trends were assessed. RESULTS:An 86% clinical failure rate (63 of the 73 hips) was observed at a mean follow-up of 4.2 ± 0.6 years (range, 3.0 to 5.5 years); 57 (78%) of the hips underwent revision at a mean of 3.2 ± 1.0 years (range, 1.0 to 5.5 years), and 6 (8%) of the hips were scheduled for revision. Patients who underwent revision surgery were younger and had greater serum metal ion levels and greater pain compared with patients who did not undergo revision. An elevated serum cobalt ion level was the most important independent factor associated with revision surgery. Cobalt ion levels decreased sharply after revision; however, some patients demonstrated persistent elevation with more gradual decline. CONCLUSIONS:Emphasizing the reporting of positive results may leave orthopaedic surgeons reticent to publicize negative results; however, the high failure rate of this implant design within 5 years prompted this report. We believe that patients and orthopaedic surgeons should be made aware of this implant's clinical problems and patients should be followed closely. Expedient revision is necessary when failure is identified, to minimize potentially severe tissue damage and metal toxicity. LEVEL OF EVIDENCE/METHODS:Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND: The effect of fixed spinal deformities on a functional pelvis from standing to sitting is not fully understood. We aimed to assess the change in preoperative sagittal pelvic tilt angle (SPTA) from standing to sitting in patients undergoing total hip arthroplasty, comparing flexible and fixed spinal deformities. METHODS: Between July 2011 and October 2011, 68 consecutive unilateral total hip arthroplasties were implanted in 68 patients with a mean age of 71 +/- 6 years. Fixed spinal deformity was defined as <10 degrees of the change in SPTA from standing to sitting. Preoperative radiographic evaluation included standing (weight-bearing) anteroposterior and lateral pelvic and lumbosacral radiographs and a sitting lateral pelvic radiograph. RESULTS: The mean standing and sitting SPTA was 3.7 degrees of anterior tilt and 17.7 degrees of posterior tilt, respectively (change of 21.4 +/- 12.5 degrees ). Seventy-five percent had flexible pelvises, all of which had a posterior tilt from standing to sitting. One patient in the fixed pelvis (1.4%) had a loss of posterior tilt from standing to sitting. The mean change of SPTA from standing to sitting in the fixed and flexible pelvis groups was 5.9 +/- 3.5 degrees to 26.7 +/- 9.6 degrees of posterior tilt, which was statistically significant (P < .05). CONCLUSION: There was a significant change in sagittal pelvic tilt from standing to sitting, especially in patients with a flexible spine, in which the functional anteversion increases with sitting. The patients with a fixed pelvis had significantly less SPTA in standing (less anteversion) with less posterior sagittal tilt in sitting, which should be incorporated in cup positioning.

BACKGROUND: The aim of this study was to evaluate long-term quality and performance of cemented posterior-stabilized (PS) total knee arthroplasty (TKA) in young and active patients with gap balancing technique. METHODS: Between January 2000 and October 2001, 55 TKAs (21 rotating platform [RP] and 34 fixed bearing [FB]) in 41 patients, 60years and younger, with University of California Los Angeles (UCLA) activity score of five and above were included in this study and prospectively followed. Clinical assessments included Western Ontario and McMaster Universities (WOMAC), Knee Society, UCLA activity score, and Patient Administered Questionnaire (PAQ). Radiographic measurements included component positioning, patellar tilt and thickness, radiolucency, loosening or osteolysis. RESULTS: At a mean follow-up of 12.3+/-0.5years (11 to 13), there was no instability, malalignment, or patellofemoral maltracking. Sixty eight percent of patients were still participating in regular recreational activities at the final follow-up. The mean satisfaction score was 9.1+/-1.9 and 8.5+/-2.1 in RP-PS and FB-PS groups, respectively. There was no malalignment or osteolysis, no revision for osteolysis or loosening. One patient in the FB-PS group underwent open reduction and internal fixation for a peri-prosthetic fracture. Overall Kaplan-Meier survivorship was 98%. CONCLUSION: The PS TKA in young and active patients can provide long-term durability and high quality of function. LEVEL OF EVIDENCE: III.

Although total knee arthroplasty is a successful and cost-effective procedure, patient dissatisfaction remains as high as 50%. Postoperative residual knee pain after total knee arthroplasty, with or without crepitation, is a major factor that contributes to patient dissatisfaction. The most common location for residual pain after total knee arthroplasty is anteriorly. Because residual pain has been associated with an un-resurfaced patella, this review includes only registry data and total knee arthroplasty with patella replacement. Some suggest that the pathogenesis of residual knee pain may be related to mechanical stimuli that activate free nerve endings around the patellofemoral joint. Various etiologies have been implicated in residual pain, including (1) low-grade infection, (2) midflexion instability, and (3) component malalignment with patellar maltracking. Less common causes include (4) crepitation and patellar clunk syndrome; (5) patellofemoral symptoms, including overstuffing and avascular necrosis of the patella; (6) early aseptic loosening; (7) hypersensitivity to metal or cement; (8) complex regional pain syndrome; and (9) pseudoaneurysm. Because all of these conditions can lead to residual pain, identifying the etiology can be a difficult diagnostic challenge. Often, patients with persistent pain and normal findings on radiographs and laboratory workup may benefit from a diagnostic injection or further imaging. However, up to 10% to 15% of patients with residual pain may have unexplained pain. This literature review summarizes the findings on the causes of residual pain and presents a diagnostic algorithm to facilitate an accurate diagnosis for residual pain after total knee arthroplasty. [Orthopedics.].

The survivorship of total hip arthroplasty in younger patients is dependent on the wear characteristics of the bearing surfaces. Long-term results with conventional polyethylene in young patients show a high failure rate. This study assessed the long-term results of a first-generation annealed highly cross-linked polyethylene (HCLPE) in uncemented total hip arthroplasty in young, active patients. Between 1999 and 2003, 112 total hip arthroplasty procedures performed in 91 patients with an average University of California Los Angeles activity score of 8 and mean age of 53 years (range, 24-65 years) were included from a prospective database. In all patients, a 28-mm metal femoral head on annealed HCLPE (Crossfire; Stryker, Mahwah, New Jersey) was used. At minimum 10-year follow-up (11.5+/-0.94 years), Kaplan-Meier survivorship was 97% for all failures (1 periprosthetic infection and 1 late dislocation) and 100% for mechanical failure (no revisions for osteolysis or loosening). This study showed low revision rates for wear-related failure and superior survivorship in young, active patients. Oxidation causing failure of the locking mechanism has not been a problem with Crossfire for up to 10 years. [Orthopedics.].

This study assessed the efficacy of highly porous cups in revision total hip arthroplasty for Paprosky types II and III acetabular bone loss. The authors identified 33 acetabular revisions in 29 patients from a prospective database (66% type III, 7 with pelvic dissociation). Initial stability was achieved with interference fit between the anterior inferior iliac spine, pubis, and ischium with cups that were 2 to 4 mm larger than the reamed acetabulum and augmented with multiple screw fixations without allograft or wedges. At mean follow-up of 6 years (range, 2.7-7.7 years) after revision surgery, no dislocation, infection, or reoperation was noted. Mean satisfaction score was 6+/-3.2. Mean anteversion and abduction angles were 43 degrees +/-4.6 degrees and 21.5 degrees +/-4.4 degrees , respectively. Complications included limp in 13% of patients, wound issues in 10%, and heterotopic ossification in 17%. Osteointegration was seen in all cups, without any migration. Mean overall osteointegration, based on the average percentage of the 3 zones in both views, was 55%+/-21% (range, 25%-95%). The most osteointegration was seen in zone I (superior) and zone VI (posterior), and the least osseointegration was seen in zone II (medial) and zone IV (anterior). This method can provide reproducible results in acetabular revision arthroplasty. [Orthopedics.].

BACKGROUND: Preoperative risk stratification and optimization of preoperative care may be helpful in reducing readmission rates after primary total joint arthroplasty. Assessment of the predictive value of individual modifiable risk factors without a tool to assess cumulative risk may not provide proper risk stratification of patients with regard to potential readmissions. As part of a Perioperative Orthopaedic Surgical Home model, we developed a scoring system, the Readmission Risk Assessment Tool (RRAT), which allows for risk stratification in patients undergoing elective primary total joint arthroplasty at our institution. The purpose of this study was to analyze the relationship between the RRAT score and readmission after primary hip or knee arthroplasty. METHODS: The RRAT, which is scored incrementally on the basis of the number and severity of modifiable comorbidities, was used to generate readmission scores for a cohort of 207 readmitted patients and two cohorts (one random and one age-matched) of 234 non-readmitted patients each. Regression analysis was performed to assess the strength of association of individual risk factors and the RRAT score with readmissions. We also calculated the odds and odds ratio (OR) at each RRAT score level to identify patients with relatively higher risk of readmission. RESULTS: There were 207 (2.08%) readmissions among 9930 patients over a six-year period (2008 through 2013). Surgical site infection was the most common cause of readmission (ninety-three cases, 45%). The median RRAT scores were 3 (IQR [interquartile range], 1 to 4) and 1 (IQR, 0 to 2) for readmitted and non-readmitted groups, respectively. An RRAT score of >/=3 was significantly associated with higher odds of readmission. CONCLUSIONS: Population health management, cost-effective care, and optimization of outcomes to maximize value are the new maxims for health-care delivery in the United States. We found that the RRAT score had a significant association with readmission after joint arthroplasty and could potentially be a clinically useful tool for risk mitigation.

The purpose of this study was to assess the durability of a non-cemented, hemispherical rim-fit, hydroxyapatite coated cup with a highly cross-linked polyethylene in 223 total hip arthroplasties. At 6-years follow-up (range, 5-9), there were no cup revisions for osteolysis or loosening. Radiologic evidence of osseointegration was based on presence of Stress Induced Reactive Cancellous Bone and radial trabeculae, seen in 47% and 93% of cups, respectively; both were most prevalent in Zone 1. There was no interference demarcation in any zones. Two cups were revised (0.9%): one for dislocation and another for infection. The Kaplan-Meier survivorship for cup revision for any failure (infection, dislocation) was 99% and for mechanical failure (osteolysis, loosening) was 100%. This design has excellent safety, efficacy and durability.

Introduction/UNASSIGNED:This article describes our technique of adding a custom-made antibiotic-coated stem to an articulating spacer to improve fixation and effectively deliver antibiotics to the medullary canal in the treatment of infection following total knee arthroplasty. Step 1 Obtain Items Required for Intraoperative Assembly/UNASSIGNED:Make sure all required items are ready prior to the start of the operation. Step 2 Remove the Components and Perform Thorough Debridement/UNASSIGNED:Remove the components and debride all cement and necrotic, devitalized, and infected tissue. Step 3 Size the Spacers/UNASSIGNED:Use the polyethylene insert to size the tibial spacer and the anteroposterior dimension of the explanted femoral component to size the femoral spacer. Step 4 Construct the Stems/UNASSIGNED:Divide the rod, coat the rods with antibiotic cement, and connect them to the articulating components. Step 5 Implant the Spacers/UNASSIGNED:Apply the cement only to the metaphysis and undersurface of the tibial spacer and place a large amount of cement on the medial and lateral condyles of the femoral spacer. Step 6 Postoperative Protocol/UNASSIGNED:Patients should walk with partial weight-bearing with a brace locked in extension for three to four weeks. Results/UNASSIGNED:. What to Watch For/UNASSIGNED:IndicationsContraindicationsPitfalls & Challenges.