Variability of pelvic axial rotation in patients undergoing total hip arthroplasty

BACKGROUND

Pelvic axial rotation affects the functional orientation of an acetabular component. Every 1° of axial rotation changes functional acetabular anteversion by 1°. There is limited information on pelvic rotation in THA patients, since it is difficult to measure on routine radiographs. Therefore, we used spine-to-ankle biplanar radiography to investigate variability in pelvic rotation in patients before and after THA.

METHODS

In 156 patients undergoing primary unilateral THA, we measured preoperative, 6 weeks and 1 year postoperative pelvic rotation in both standing and sitting positions using a biplanar radiography system. Patients with fixed pelvic rotation had a similar magnitude and direction of pelvic rotation in all standing or sitting images. We further identified patients with position-independent or position-dependent fixed pelvic rotation.

RESULTS

Pelvic rotation was common in THA patients, with 82 patients (53% of 156 patients) having at least 1 image with > 7° of rotational deformity. 12 patients (8% of 156 patients) had fixed rotation, 6 patients (4%) had position-independent fixed axial rotation and 6 patients (4%) had position-dependent fixed axial rotation.

CONCLUSIONS

It may be important to recognise whether a THA patient has a fixed pelvic axial rotational deformity, where 1 hip is consistently forward or backward in functional imaging. Fixed rotation will increase or decrease the functional anteversion of an acetabular component depending on THA side. Further research might better characterise associations and predictors of fixed axial rotation and its impact on patient outcomes after THA.

A comparison of clinical and patient-reported outcome measures of TKR: Comparison of Asian to North American patients

BACKGROUND

Cultural differences between continents may also affect the outcome on interventions. This study compared an Asian and North American cohort of total knee replacement (TKR) patients.

QUESTIONS/PURPOSES

This study aims to compare the patient-reported outcome measures as well as a functional outcome after TKR between these two different patient populations with a different cultural societal background in two different countries.

PATIENTS AND METHODS

A retrospective study on two cohorts of 76 Asian TKR patients and 64 North American TKR patients were compared. Demographics, patient-reported outcome measures (Knee Society Score (KSS), Patient-Administered Questionnaire (PAQ), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)), knee range of motion (RoM), and radiographic component position were compared.

RESULTS

The Asian cohort had more females compared to the North American and significantly worse preoperative RoM, and worse KSS function score and PAQ pain scores. The preoperative KSS knee score and WOMAC scores were comparable between the two groups. Postoperatively, the differences in WOMAC and KSS knee scores were significant, while KSS function and PAQ were comparable between groups.

CONCLUSIONS

Even though Asian TKR patients had significantly worse preoperative scores, their postoperative outcomes were comparable to North Americans. The higher preoperative functional deficit and the higher pain levels in the Asian population might be due to cultural differences and/or socioeconomic reasons, which made Asian patients present with more severe conditions in the preoperative consultation for a possible surgical treatment compared to North Americans. More research is needed to investigate the difference between these cultural impacts on TKR outcomes.

LEVEL OF EVIDENCE

Level III/Retrospective cohort study.

Role of Anatomical Patella Replacement on Anterior Knee Pain

BACKGROUND

Anterior knee pain (AKP) remains a complex issue affecting patient satisfaction after total knee arthroplasty. Several radiographic parameters have been shown to be causative factors with various designs. The aim of this study is to evaluate the known radiographic parameters of AKP and clinical outcomes (ie, AKP) in the setting of a modern prosthesis with an anatomic patella button.

METHODS

Between July 2012 and December 2013, 90 total knee arthroplasties received 3 skyline views taken at 30°, 45°, and 60°. A patient-administered questionnaire was administered at 2-year follow-up to assess the incidence of AKP, painless noise, and satisfaction. Radiographs were analyzed for patellofemoral overstuffing, patellar tilt, and patellar displacement, and evaluated the patella resection angle.

RESULTS

On the patient-administered questionnaire, 10 (11.1%) patients reported AKP of a mild-to-moderate nature. Thirty-one had the best view at 30 Merchant views, 24 had best views at 45, and 35 had best views at 60. We found that patellar resection angle correlated with AKP (odds ratio 1.21, P = .044) and painless noise (odds ratio 1.22, P = .034). Patellar displacement and patellofemoral stuffing did not correlate with AKP or painless noise. No radiographic measurements correlated with changes in Knee Society Score pain or function scores or range of motion.

CONCLUSION

We found that a patellar resection angle correlated with the incidence of AKP and painless noise at 2-year follow-up. We failed to find any correlation with patellofemoral overstuffing, patellar displacement, or patellar tilt with clinical outcomes. We recommend the use of 3 Merchant views to fully evaluate the patellofemoral joint.

Wear Analysis of Highly Cross-Linked Polyethylene in Young and Active Patients at Average Fourteen Years: A Concise Follow-Up of a Previous Report

BACKGROUND

Concerns persist regarding the oxidative stability of annealed highly cross-linked polyethylene (HXLPE) and hence its wear performance especially long term in young and active patients. The purpose of this study is to assess the wear rates and clinical outcomes of a first-generation annealed HXLPE.

METHODS

Forty-six patients (57 hips) with noncemented fixation, a mean age of 53 years, and a mean University of California Los Angeles activity score of 8 underwent primary total hip arthroplasty. A 28-mm femoral head against HXLPE liner was used in all cases. Linear wear rates were measured by 2 independent observers. Radiological and clinical assessments were recorded.

RESULTS

At a mean of 14 years (range 10-17), the wear rate was 0.03 mm/y (SD ±0.02). There were no revisions for wear-related complications. Using revision for wear-related complications as an endpoint, the survivorship was 100% and we observed no osteolysis. Western Ontario and McMaster Universities Osteoarthritis Index, patient administered questionnaire, and Hospital for Special Surgery hip scores were 91/100, 5/100, and 37/40 respectively.

CONCLUSION

This study confirms that a first-generation annealed HXLPE shows excellent wear and clinical results at 10-17 years in young and active patients. Oxidative degradation of an annealed HXLPE does not adversely affect wear and shows no other wear-related complications.

Wear Rates With Large Metal and Ceramic Heads on a Second Generation Highly Cross-Linked Polyethylene at Mean 6-Year Follow-Up

BACKGROUND

Bearing surface wear and osteolysis are major factors limiting the durability of total hip arthroplasty (THA). Second generation annealed highly cross-linked polyethylene (HXLPE) and ceramics were introduced to THA for their excellent wear rates. However, there is little data comparing the wear rates of metal and ceramic heads on second generation HXLPE.

METHODS

Sixty patients who received a noncemented THA with a 32- or 36-mm delta ceramic head were matched with 60 THAs with a 32- or 36-mm metal head based on gender, head size, follow-up, and University of California, Los Angeles activity score. Linear and volumetric wear rates were measured.

RESULTS

At mean 6-year follow-up, the mean linear wear rates were 0.012 mm/y (standard deviation [SD] 0.045; 95% confidence interval [CI] 0.001-0.024) and 0.018 mm/y (SD 0.025; 95% CI 0.012-0.025) for the ceramic and metal groups, respectively (P = .724). The mean volumetric wear rates for the ceramic and metal head groups were 11.9 (SD 43.0; 95% CI 0.7-23.0) and 17.3 (SD 23.9; 95% CI 11.1-23.4), respectively. No significant differences were detectable in either the mean linear or volumetric wear rates (P = .380 and P = .398, respectively).

CONCLUSION

Second generation HXLPE had low wear rates and we were unable to detect a significant difference in wear rates with 32- or 36-mm metal and ceramic heads. We believe that this is due to the excellent tribological properties of second generation HXLPE. We continue to use ceramic as standard of care because of issues of trunnionosis with metal heads.

Incidence of Heterotopic Ossification Following a Multimodal Pain Protocol in Total Hip Arthroplasty With the Posterior Approach

Heterotopic ossification (HO) is prevalent after total hip arthroplasty (THA). Oral nonsteroidal anti-inflammatory drugs and cyclooxygenase-2 (COX-2) inhibitors have reduced the incidence of HO; however, to the authors' knowledge, no studies have reported the incidence and severity of HO with a pain protocol highlighted by celecoxib in the pre- and postoperative period with a posterolateral approach. Between October 2014 and October 2015, a retrospective study was conducted of 687 consecutive primary THAs with minimum 1-year follow-up performed between January 2009 and December 2013. All patients underwent a posterolateral THA with a multimodal pain protocol consisting of preoperative celecoxib; local steroid infiltration intraoperatively; postoperative celecoxib, dexamethasone, and ketorolac; and aspirin or warfarin thromboprophylaxis. For all patients, pre- and postoperative radiographs were examined and classified for HO using the Brooker classification. Interobserver reliability was calculated for both incidence of HO and Brooker classification. Overall, HO was present around 98 (14.3%) THAs. The incidence of Brooker I, II, and III HO was 38 (5.5%), 47 (6.8%), and 12 (1.7%), respectively. No patients required surgical excision or had radiographic evidence of Brooker IV HO. Multivariate logistic regression identified male sex and hypertrophic osteoarthritis as significant risk factors. The use of aspirin for thromboprophylaxis significantly reduced the incidence of HO. This study found the overall incidence of HO when using celecoxib during a posterior THA to be 14.3%, which is similar to what others have reported with the direct lateral approach and with other COX-2 inhibitors for a posterior approach. Risk factors include male sex and preoperative hypertrophic osteoarthritis. [Orthopedics. 2018; 41(1):e92-e97.].

MRI, Retrieval Analysis, and Histologic Evaluation of Adverse Local Tissue Reaction in Metal-on-Polyethylene Total Hip Arthroplasty

BACKGROUND

The severity and location of adverse local tissue reaction (ALTR) seen in metal-on-polyethylene total hip arthroplasty (THA) is not well described.

METHODS

We retrospectively reviewed the records of patients who underwent a revision THA using our biomechanics database. We included all patients who underwent revision surgery for the diagnosis of ALTR with THA implants that had modularity solely at the head-neck junction and excluded patients with implant modularity at sites other than the head-neck junction. Magnetic resonance imaging (MRI) was evaluated by a fellowship-trained radiologist who specializes in evaluating metal artifact reducing MRI sequences to quantify the ALTR lesions. Histology was evaluated for findings of ALTR using the Campbell score.

RESULTS

We identified 11 patients in the database. Eight patients had an MRI ALTR grade of severe and 7 did based on the histology score. The mean synovial volume was 218,658 mm³ (range 23,461-451,435 mm³) with a mean maximal synovial thickness of 15.3 mm (range 3-34.3 mm). A disruptive infiltration of the abductors due to pseudocapsule invasion was seen in 67% of the patients with 3 not having abductor involvement. Mean preoperative cobalt and chromium levels were 5.4 ppb (range 1-12.3 ppb) and 1.1 ppb (range 0.6-2.4 ppb), respectively.

CONCLUSION

Patients with ALTR from head-neck junction corrosion in metal-on-polyethylene THA may present with large pseudotumors that have previously been under appreciated. Mean preoperative serum cobalt and chromium ion levels remained relatively low, and MRI was an effective way to characterize the size and location of these lesions.

Clinical and Radiographic Results of Attune and PFC Sigma Knee Designs at 2-Year Follow-Up: A Prospective Matched-Pair Analysis

BACKGROUND

Anterior knee pain (AKP) and/or crepitation are important causes of dissatisfaction after total knee arthroplasty (TKA). Aim of this prospective, matched-pair study was to compare 2 different designs of patellofemoral (ie, trochlear groove) TKA. The Attune knee has an anatomic trochlear groove with a medialized dome patellar component vs the PFC Sigma with a single radius trochlear groove with a domed shaped patella.

METHODS

Between January 2010 and December 2014, 100 consecutive Attune TKAs were matched to 100 PFC Sigma TKAs based on age, gender, side, and body mass index. All surgeries were performed via medial parapatellar approach and used cemented, posterior-stabilized implants with patellar resurfacing. Clinical evaluations were assessed using Knee Society Scores (KSS) and a patient-administered questionnaire at 2-year follow-up (range, 1.5-3 years).

RESULTS

Based on the KSS clinical rating system, excellent clinical results were achieved in 89.4% and 90.7% of Attune and PFC Sigma TKAs, respectively. There were no significant differences in the KS pain or function scores. The overall incidence of AKP was significantly lower with the Attune knee compared to that of the PFC Sigma (12.5% vs 25.8%; P = .02). The incidence of hearing or feeling noise was also less with the Attune knee (17.7% vs 30.9%; P = .02). The incidence of painful crepitation was low in both groups (1.0% vs 4.1%) with no significant difference between groups (P = .37). Both groups had similar high satisfaction scores of 8.6 and 8.4 for the Attune and PFC groups, respectively (P = .09).

CONCLUSION

At 2-year follow-up, there were no differences between the PFC Sigma and Attune knees in KSS or satisfaction. However, the Attune group had a lesser incidence of AKP and crepitation. Further studies should focus on AKP and noise in cruciate-retaining knees.

Long-term Results of a First-Generation Annealed Highly Cross-Linked Polyethylene in Young, Active Patients

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.

Diagnostic Algorithm for Residual Pain After Total Knee Arthroplasty

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.

Use of Oversized Highly Porous Cups in Acetabular Revision

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°±4.6° and 21.5°±4.4°, 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.

Severe Hand Osteoarthritis Strongly Correlates With Major Joint Involvement and Surgical Intervention

BACKGROUND

The presence of hand osteoarthritis (OA) increases the risk for developing OA in other major joints. Although genetic predisposition has been implicated in its causation, its exact role has yet to be established. The association of hand OA with symptomatic and asymptomatic major joints has not been previously studied.

METHODS

Hundred consecutive patients had a hand photo taken for visual documentation of the hand joints. Radiographs of hand and all major symptomatic joints were analyzed and classified using the Kellgren-Lawrence scale by 2 independent observers including an orthopedic radiologist.

RESULTS

Severe hand OA was present in 91% of the patients. Radiographic analysis showed that the hip was involved in 88% of the patients, of whom 85.2% (75) were symptomatic and 14.7% (13) were asymptomatic. Hip arthroplasty was required by 62.5% (55) of symptomatic hip patients. Knee involvement was present in 37% of the patients; all were symptomatic and 81.1% (30) of these required knee arthroplasty. Bilateral surgery was performed in 33% (28) and "2 joint (hip and knee)" surgery was performed in 6% (5). Spine involvement was present in 72% of the patients. There was a significant correlation between hand radiographic findings of OA and hip (r = 0.68; P = .03), knee (r = 0.58; P = .042), and spine (r = .39; P = .05) involvement.

CONCLUSION

There was a significant correlation between severe hand OA and hip, knee, and spine involvement. Severity of Hand OA can have a predictive value on multiple joint involvement and risk of surgical intervention. This study emphasizes the need to investigate the genetic predisposition in causation of OA.

Effect of Spinal Deformity on Pelvic Orientation from Standing to Sitting Position

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° 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° of anterior tilt and 17.7° of posterior tilt, respectively (change of 21.4 ± 12.5°). 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° to 26.7 ± 9.6° 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.

Long-term results of total knee arthroplasty in young and active patients with posterior stabilized design

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, 60 years 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±0.5 years (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.

Performance of Non-Cemented, Hemispherical, Rim-Fit, Hydroxyapatite Coated Acetabular Component

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.

Fixed Bearings versus Rotating Platforms in Total Knee Arthroplasty

Rotating platforms were introduced as an alternative to fixed bearings in hopes of providing more natural kinematics and improved clinical outcomes. In-vitro wear studies showed significantly less wear with rotating platforms as opposed to fixed-bearing designs. Kinematic follow-up studies showed significantly improved axial rotation with rotating-platform knees. However, these benefits have failed to translate into improved clinical outcomes or survivorship. This article reviews our institution's experience, as well as the latest clinical research on wear, kinematics, clinical outcomes, and survivorship of fixed-bearing and rotating-platform knees.

Patient-controlled epidural analgesia or multimodal pain regimen with periarticular injection after total hip arthroplasty: a randomized, double-blind, placebo-controlled study

BACKGROUND

The optimal postoperative analgesia after primary total hip arthroplasty remains in question. This randomized, double-blind, placebo-controlled study compared the use of patient-controlled epidural analgesia (PCEA) with use of a multimodal pain regimen including periarticular injection (PAI). We hypothesized that PAI would lead to earlier readiness for discharge, decreased opioid consumption, and lower pain scores.

METHODS

Forty-one patients received PAI, and forty-three patients received PCEA. Preoperatively, both groups were administered dexamethasone (6 mg, orally). The PAI group received a clonidine patch and sustained-release oxycodone (10 mg), while the PCEA group had placebo. Both groups received combined spinal-epidural anesthesia and used an epidural pain pump postoperatively; the PAI group had normal saline solution, while the PCEA group had bupivacaine and hydromorphone. The primary outcome, readiness for discharge, required the discontinuation of the epidural, a pain score of <4 (numeric rating scale) without parenteral narcotics, normal eating, minimal nausea, urination without a catheter, a dry surgical wound, no acute medical problems, and the ability to independently transfer and walk 12.2 m (40 ft).

RESULTS

The mean time to readiness for discharge (and standard deviation) was 2.4 ± 0.7 days (PAI) compared with 2.3 ± 0.8 days (PCEA) (p = 0.86). The mean length of stay was 3.0 ± 0.8 days (PAI) compared with 3.1 ± 0.7 days (PCEA) (p = 0.46). A significant mean difference in pain score of 0.74 with ambulation (p = 0.01; 95% confidence interval [CI], 0.18 to 1.31) and 0.80 during physical therapy (p = 0.03; 95% CI, 0.09 to 1.51) favored the PCEA group. The mean opioid consumption (oral morphine equivalents in milligrams) was significantly higher in the PAI group on postoperative day 0 (43 ± 21 compared with 28 ± 23; p = 0.002) and postoperative days 0 through 2 (136 ± 59 compared with 90 ± 79; p = 0.004). Opioid-Related Symptom Distress Scale (ORSDS) composite scores for severity and bothersomeness as well as scores for nausea, vomiting, and itchiness were significantly higher in the PCEA group (p < 0.05). Quality of Recovery-40 scores and patient satisfaction were similar.

CONCLUSIONS

PAI did not decrease the time to discharge and was associated with higher pain scores and greater opioid consumption but lower ORSDS scores compared with PCEA. The choice for analgesic regimen may depend on a particular patient's threshold for pain and the potential side effects.

Reproducible fixation with a tapered, fluted, modular, titanium stem in revision hip arthroplasty at 8-15 years follow-up

The use of tapered, fluted, modular, distally fixing stems has increased in femoral revision surgery. The goal of this retrospective study was to assess mid-term to long-term outcomes of this implant. Seventy-one hips in 70 patients with a mean age of 69 years were followed for an average of 10 years. Preoperative HHS averaged 50 and improved to 87 postoperatively. Seventy-nine percent hips had Paprosky type 3A or more bone-loss. All stems osseointegrated distally (100%). Two hips subsided >5mm but achieved secondary stability. Sixty-eight percent hips had evidence of bony reconstitution and 21% demonstrated diaphyseal stress-shielding. One stem fractured near its modular junction and was revised with a mechanical failure rate of 1.4%. Distal fixation and clinical improvement were reproducibly achieved with this stem design.

Durable fixation achieved with medialized, high hip center cementless THAs for Crowe II and III dysplasia

BACKGROUND

A high hip center total hip arthroplasty (THA) for dysplasia allows more complete socket coverage by native bone at the expense of abnormal hip biomechanics. Despite poor results with cemented components, intermediate-term results with cementless cups at a high hip center have been promising, but there are few reports at long-term followup without bone graft.

QUESTIONS/PURPOSES

The purpose of this study was to examine (1) survivorship; 2) radiographic results; and 3) hip scores at a minimum of 10 years for patients treated with high hip center cementless THA for Crowe II and III dysplasia without bone graft.

METHODS

We reviewed charts and radiographs of 32 patients with Crowe II or III dysplasia who were treated with high hip center cementless THA; at a mean followup of 12 years (range, 10-21 years), 23 patients (27 hips) were available for review. We sought to medialize cups to the inner table to achieve bony coverage of > 75%. At final followup, the WOMAC and Harris hip scores were recorded. Radiographic analysis including computerized wear evaluation was performed. Radiographic parameters were compared with a control group of 23 patients with Crowe I dysplasia who had cementless cups placed at an anatomic hip center; among the high hip center reconstructions, we also compared wear between those in the superolateral and superomedial quadrants.

RESULTS

Kaplan-Meier survivorship for all-cause revisions was 97% (95% confidence interval, 79%-99%) in the high hip center group; this was no different from the anatomic hip center group. There were no revisions for acetabular loosening. Wear rates did not differ significantly between the high hip center and the control group, but lateralized high hip centers were associated with higher (p = 0.002) wear. Hip scores were excellent in both groups.

CONCLUSIONS

In Crowe II and III dysplasia, a high hip center cementless cup obviates the need for bone graft and provides durable fixation beyond 10 years. Medialization of these reconstructions seems important to decrease wear.

Assessment of reactive synovitis in rotating-platform posterior-stabilized design: a 10-year prospective matched-pair MRI study

This is the first long-term (mean 11.6 years), prospective, matched-pair study (based on age, gender, BMI and UCLA scores) using MAVRIC (multi-acquisition variable-resonance image combination) magnetic resonance imaging to analyze reactive synovitis and osteolysis between rotating-platform posterior-stabilized (RP-PS), fixed-bearing metal-back (FB-MB), and all-polyethylene tibial (APT) in active patients (24 total, 8 in each group, mean age of 64 years, mean UCLA of 8.5) with identical femoral component and polyethylene. Reactive synovitis was observed in 6 RP-PS (75%), all 8 FB-MB (100%), and 6 APT (75%). There was a significant difference between the RP-PS and FB-MB knees in volumetric synovitis (P=0.023). Osteolysis with bone loss more than 4mm was seen in 3 FB-MB, 2 APT and none for RP-PS. These were not statistically significant.

Safety and efficacy of non-cemented femoral fixation in patients 75 years of age and older

The aim of this study was to assess peri-operative complications, safety and efficacy of non-cemented femoral fixation in total hip arthroplasty (THA) as compared to cemented femoral fixation in the elderly population. Fifty-two matched pair analysis of patients with 75 years of age and older (104 patients), who underwent primary THA from June 1997 to December 2004, was performed based on age, sex, BMI, and Charnley classification. Mean age was 81 years (75-101) and the average follow up was 3.1 ± 2.9 years (1.2-6.4). There was no difference in peri-operative cardiopulmonary complications, pulmonary failures, deep venous thrombosis, pulmonary embolus, length of stay, or discharge deposition between the two groups. Non-cemented fixation is safe and effective in patients older than 75 years of age.

A novel method for accurate and reproducible functional cup positioning in total hip arthroplasty

Cup positioning is an important variable for short and long term function, stability, and durability of total hip arthroplasty (THA). This novel method utilizes internal and external bony landmarks, and the transverse acetabular ligament for positioning the acetabular component. The cup is placed parallel and superior to the transverse ligament and inside the anterior wall notch of the true acetabulum, then adjusted for femoral version and pelvic tilt and obliquity based on weight bearing radiographs. In 78 consecutive THAs, the mean functional anteversion and abduction angles were 17.9° ± 4.7° and 41.7° ± 3.8°, respectively. 96% of the functional anteversion measurements and 100% of the functional abduction angles were within the safe zone. This technique is an easy, reproducible, and accurate method for functional cup placement.

Long-term performance of ceramic and metal femoral heads on conventional polyethylene in young and active patients: a matched-pair analysis

BACKGROUND

Ceramic femoral heads produce less wear of the opposing polyethylene than do metal femoral heads in wear simulation studies. This is a matched-pair analysis of the wear of ceramic and metal femoral heads on conventional polyethylene in uncemented total hip replacements in young, active patients at a minimum of fifteen years of follow-up.

METHODS

From June 1989 to May 1992, thirty-one matched pairs of alumina ceramic or cobalt-chromium metal femoral heads were identified. Patients were matched on the basis of age, sex, body weight, diagnosis, and activity level. The mean age was 55 ± 9 years (range, twenty-three to sixty-five years) at the time of surgery. All procedures were performed with a posterolateral surgical approach by a single surgeon using press-fit Ranawat-Bernstein femoral stems, Harris-Galante-II acetabular cups, GUR 4150 conventional polyethylene (sterilized in argon), and 28-mm-diameter femoral heads. Wear measurements were performed by two independent observers using the computer-assisted Roman software.

RESULTS

The average duration of follow-up was 17 ± 1.7 years (range, fifteen to twenty years). The mean Hospital for Special Surgery hip scores (and standard deviation) in the ceramic and metal groups were 39 ± 4 and 40 ± 3 at the time of final follow-up. The University of California Los Angeles activity score at the time of the final follow-up was 6 ± 2 for both groups. The mean wear rates for the ceramic group and the metal group were 0.086 ± 0.05 mm/yr and 0.137 ± 0.05 mm/yr, respectively (p = 0.0015). There was one reoperation in the ceramic group because of distal femoral osteolysis. There were three failures in the metal group, requiring isolated liner exchange in two hips and revision of the acetabular component in one hip because of wear-induced osteolysis and/or loosening that caused symptoms. Five hips in the ceramic group and six hips in the metal group had radiographic evidence of acetabular or femoral osteolysis, but none were symptomatic.

CONCLUSIONS

Ceramic femoral heads produced significantly less wear on conventional polyethylene liners at the time of long-term follow-up than did metal heads in this matched-pair analysis of young and active patients with uncemented fixation.

Computed tomographic evaluation of femoral component rotation in total knee arthroplasty

BACKGROUND

Optimal femoral component rotational alignment in total knee arthroplasty (TKA) is crucial to establish a balanced knee reconstruction. Unbalanced knees can lead to instability, patellofemoral problems, persistent pain, stiffness, and generally poorer outcomes including early failure. Intraoperative techniques to achieve this optimal femoral component rotation include the use of the transepicondylar axis (TEA), the posterior-condylar-cut-parallel-to-the-tibial-cut (PCCPTC) technique and the anteroposterior axis technique (Whiteside's line). The purpose of this study was to compare the PCCPTC technique to the TEA technique using computed tomography (CT) scans to assess femoral component rotational alignment.

MATERIALS AND METHODS

This study used postoperative CT scans to compare the degree of femoral component rotation obtained with the use of PCCPTC technique and the TEA. The femoral component rotation of 30 TKA was measured on postoperative CT scans the angle of deviation between the two lines radiographic trans-epicondylar axis (rTEA) and femoral prosthesis posterior condylar line (FPPCL) was determined. This angle represented the rotation of the femoral component relative to the true rTEA.

RESULTS

The degree of rotation measured 2.67 ± 1.11 degrees in the PCCPTC group and 5.60 ± 1.64 degrees in the TEA group.

CONCLUSION

The use of the TEA technique for determining rotational alignment in TKR results in excessive external rotation of the femoral component compared to the PCCPTC technique.

What would you do?: challenges in hip surgery

A moderator and panel of five experts led an interactive session in discussing five challenging and interesting patient case presentations involving surgery of the hip. The hip pathologies reviewed included failed open reduction internal fixation of subcapital femoral neck fracture, bilateral hip disease, evaluation of pain after metal-on-metal hip arthroplasty, avascular necrosis, aseptic loosening secondary to osteolysis and polyethylene wear, and management of ceramic femoral head fracture.

The "Inside-Out" Technique for Correcting a Fixed Varus Deformity with Flexion Contracture in Total Knee Arthroplasty

Introduction

The inside-out technique is a safe and reproducible method to effectively correct a fixed varus-flexion deformity during total knee arthroplasty by performing a posteromedial capsular release and so-called pie-crust lengthening of the superficial medial collateral ligament (sMCL).

Step 1 Preoperative Planning

Analyze preoperative radiographs as a key step in planning the surgery for the required amount of osseous cuts and soft-tissue release.

Step 2 Exposure

Obtain adequate exposure for proper visualization and assessment.

Step 3 Tibial and Femoral Cuts

Adequate bone cuts with proper alignment are an essential step of this technique.

Step 4 Posteromedial Capsulotomy

This is the most important step for extension balancing in knees with flexion contracture; the posteromedial aspect of the capsule in varus deformity should be safely incised at the level of the tibial cut.

Step 5 Pie-Crusting of the sMCL

Perform pie-crusting followed by serial manipulations in a controlled manner to avoid overrelease of the sMCL.

Step 6 Flexion Gap Balancing

This is a key step for proper balancing, femoral sizing, rotation, lateralization, and patellofemoral tracking.

Results

From October 2006 to December 2009, thirty-one consecutive patients (thirty-four knees) with a severe fixed varus-flexion deformity (varus alignment of ≥15° and flexion contracture of ≥5°) underwent total knee arthroplasty with the inside-out technique.

What to Watch For

IndicationsContraindicationsPitfalls & Challenges.

The effect of patellar replacement technique on patellofemoral complications and anterior knee pain

Routine patella replacement with total knee arthroplasty has not been universally adopted because of associated patellofemoral complications such as anterior knee pain (AKP). In the proposed technique, the articular surface of the lateral facet of the patella is excised to the depth of the subchondral bone, and the medial facet is then cut parallel to the anterior surface. We evaluated any correlation between various radiographic parameters and AKP in 100 consecutive fixed-bearing posterior-stabilized total knee arthroplasties. There were no cases of fracture, avascular necrosis, subluxation, dislocation, patellar baja, or overstuffing of the patella. Anterior knee pain was present in 11% of cases, and no cases were severe or disabling. There were no correlations between AKP, range of motion, patellar size and shape, and any of the radiographic parameters.

Correcting fixed varus deformity with flexion contracture during total knee arthroplasty: the "inside-out" technique: AAOS exhibit selection

BACKGROUND

Traditional methods for correcting a severe varus and flexion deformity of the knee during total knee arthroplasty can often lead to excessive release of the medial collateral ligament, hematoma formation, and reliance on constrained implants. The "inside-out" technique for correction of varus deformities involves performing a posteromedial capsulotomy at the level of the tibial cut and incising the superficial medial collateral ligament in a pie-crust manner in extension followed by serial manipulations with valgus stress. Our hypothesis was that this technique effectively corrects severe knee varus and flexion deformity with a reduced risk of complications.

METHODS

Thirty-one consecutive patients (thirty-four knees) with a severe fixed varus and flexion deformity (varus alignment of ≥ 15° and flexion contracture of ≥ 5°) underwent total knee arthroplasty with use of the inside-out technique between October 2006 and December 2009. Physical examination, radiographs, and multiple outcome instruments were used to evaluate the results.

RESULTS

The mean duration of follow-up was 3.1 ± 1.1 years (range, 1.7 to 4.9 years). There were no cases of hematoma formation, excessive release of the medial collateral ligament, or acute or delayed instability. A semi-constrained TC3 implant was used in two cases. The mean preoperative coronal alignment was 21.1° ± 4° of varus, which was corrected to 4.5° ± 1.6° of valgus after surgery. The mean preoperative flexion contracture was 10° ± 3.5°. Postoperatively, two patients (three knees) had a residual flexion contracture, which was ≤5° in all cases. The mean range of knee motion improved from 103.3° ± 14.1° preoperatively to 119.1° ± 8° at the time of final follow-up. The mean Knee Society Score pain subscore improved from 39.5 ± 12.6 to 93.2 ± 10.5, and the function subscore improved from 47.1 ± 17.8 to 78.5 ± 21.9. There was no evidence of implant loosening or osteolysis on radiographs.

CONCLUSIONS

The technique described was safe, reproducible, and effective in treating combined varus and flexion deformity of the knee during total knee arthroplasty. It reduced the risks of over-release of the medial collateral ligament, hematoma formation, and the need for constrained implants.

Pain management after total knee arthroplasty using a multimodal approach

Improvements in pain management techniques over the past decade have had a significant impact on the outcomes of total knee arthroplasty. Of these techniques, multimodal approaches have shown potential. The purpose of this study was to compare the results of periarticular injection (PAI) to a combination of patient-controlled epidural analgesia and femoral nerve block (PCEA/FNB). Ninety patients undergoing primary unilateral total knee arthroplasty between June 2010 and March 2011 were randomized into 2 groups. The first group received the PCEA/FNB protocol, whereas the second group received the PAI. Mean patient age was 66.1 ± 8.7 years. All patients were operated on using a similar standard medial parapatellar approach, and all received preemptive analgesia and postoperative pain protocols. All patients were interviewed twice daily for the first 3 days postoperatively, once on day 7, and once in month 6. The 2 groups had similar readiness for discharge (PCEA/FNB group, 3.3 ± 1.2 days; PAI group, 3.2 ± 1.9 days). The results indicated no statistical difference between the 2 groups in 3 of 4 categories (rest in the morning, rest in the evening, and ambulation in the morning). Pain on ambulation was the only category that was statistically lower in the PCEA/FNB group than in the PAI group.Although the study demonstrates similar results between the 2 groups, PAI can play a major role in postoperative pain control in institutions that may not have appropriately trained individuals, equipment, and resources for PCEA/FNB. It also reduces many of the side effects and complications associated with regional anesthesia.

Properties of the patient administered questionnaires: new scales measuring physical and psychological symptoms of hip and knee disorders

The Patient Administered Questionnaires (PAQ) incorporate physical and psychological symptoms into one scale and permit more comprehensive self-reports for hip and knee disorders. We tested the psychometric properties of the PAQ-Hip and PAQ-Knee. Correlations between baseline PAQ-Hip and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were .39 to .72 (n = 102), .39 to .69 for score change (n = 68 post-total hip arthroplasty), and most κ values > .60 (n = 50). Correlations between baseline PAQ-Knee and WOMAC were .35 to .64 (n = 100), .62 to .79 for score change (n = 43 post-total knee arthroplasty), and most κ values >.60 (n = 51). For both scales, effect sizes were higher than for the WOMAC, and there was modest correlation between physical and psychological questions, indicating these concepts are not completely interchangeable. Thus, the PAQ scales have strong psychometric properties and are unique compared with existing scales by including physical and psychological symptoms.

Ten-year follow-up of a rotating-platform, posterior-stabilized total knee arthroplasty

BACKGROUND

The rotating-platform, posterior-stabilized knee was designed to decrease polyethylene wear and to address challenges associated with Low Contact Stress mobile-bearing knees. The purpose of the present prospective study was to investigate the long-term clinical and radiographic results and the survival rate for this implant.

METHODS

From January 2000 to October 2001, 117 consecutive patients (138 knees) underwent rotating-platform posterior-stabilized total knee arthroplasty with cement. All patients were followed prospectively. At a mean of 10 ± 0.4 years (range, 9.5 to eleven years) of follow-up, twenty patients had died and eight had been lost to follow-up, leaving eighty-nine patients (106 knees) for analysis.

RESULTS

A good to excellent result according to the Knee Society pain score, which improved from an average of 44 to 94 points, was achieved in 96% (eighty-five) of the eighty-nine patients in the final cohort. The mean knee motion improved from 111° to 119°. The prevalence of postoperative pain was 14%. The prevalence of asymptomatic crepitation was 9.4%, and the prevalence of painful crepitation requiring scar excision was 3.8%. Radiographic analysis revealed no malalignment, aseptic loosening, or osteolysis. There were three revisions: one for the treatment of infection and two for the treatment of traumatic supracondylar fractures. Kaplan-Meier analysis revealed that the ten-year survival rate was 100% with revision due to mechanical failure as the end point, 97.7% with revision for any reason as the end point, and 95% with any reoperation as the end point.

CONCLUSIONS

The ten-year follow-up of the rotating-platform, posterior-stabilized total knee arthroplasty demonstrated excellent clinical results and survival rates with no failures due to osteolysis or loosening.

Minimum 5-year wear analysis of first-generation highly cross-linked polyethylene in patients 65 years and younger

The purpose of this study was to analyze wear rates of highly cross-linked polyethylene comparing the Martell and the Roman methods in 112 total hip arthroplasties in patients 65 years and younger, with a mean follow-up of 5.7 years. The mean wear rates in the Martell and Roman methods were 0.014 ± 0.05 mm/y and 0.011 ± 0.04 mm/y when including all values and 0.043 ± 0.028 mm/y and 0.038 ± 0.02 mm/y when negative values were assumed to be zero, respectively. Both Roman and Martell methods showed similar low wear rates with negative values. The Roman method had higher precision and was more user friendly because it required less steps to measure wear, especially when comparing with the manual feature of Martell method.

Safety and efficacy of a rotating-platform, high-flexion knee design three- to five-year follow-up

Our hypothesis was that a high-flexion rotating-platform posterior stabilized (RP-PS) design could maximize range of motion (ROM) and improve deep-flexion activities. Eighty-seven consecutive patients (109 knees) with high-flexion RP-PS design were prospectively followed up for a minimum of 3 years. Radiographic and clinical outcomes were analyzed using Knee Society Score criteria and Western Ontario and McMaster Universities Osteoarthritis Index. Good to excellent clinical scores were achieved in 96% of the knees. There were no cases of infection, malalignment, loosening, osteolysis, or spinout. The mean preoperative ROM improved from 110.7° to 124° postoperatively. High-flexion activities such as squatting and kneeling were achieved in 62% and 60% of patients, respectively. High-flexion knee implant is safe and improves ROM and deep-flexion activities. Persistent pain is an important cause of dissatisfaction after total knee arthroplasty.

All-polyethylene tibial implant in young, active patients a concise follow-up, 10 to 18 years

This is a long-term follow-up report of all-polyethylene tibial components in 60 years and younger, active patients. At the mean follow-up of 12.4 ± 2.7 (range, 10-18 years), no more patients were deceased or lost to follow-up, leaving 32 patients (44 knees) for final analysis. Good to excellent results were achieved in 96% of patients. The mean Western Ontario and McMaster Universities Osteoarthritis Index and Knee Society Score were 31 and 97, respectively. Sixty-two percent of patients were participating in sport activities such as running, gym exercises, and playing tennis or golf, with a mean UCLA score of 7.2. There were no cases of malalignment, aseptic loosening, excessive wear, or osteolysis. Seven patients (9 knees) had incomplete, nonprogressive demarcation at the zone 1 tibial interface. Kaplan-Meier survivorship at 10 years for revision due to mechanical reasons and for all failures was 97.7% and 95.5%, respectively.

The natural history of anterior knee pain in 2 posterior-stabilized, modular total knee arthroplasty designs

Anterior knee pain (AKP) has been a persistent complaint after total knee arthroplasty; however, the natural course of this complaint has not been fully investigated. This is a 10-year follow-up report of a prospective, randomized study between the Insall-Burstein II (Zimmer, Warsaw, IN) and the Press Fit Condylar Modular (Johnson & Johnson, Raynham, MA) knees. Up to one third of total knee arthroplasties will experience mild to moderate AKP at 1-year follow-up, which will persist in approximately 30% of these previously symptomatic knees at 10-year follow-up. New-onset AKP will develop in approximately 10% of previously asymptomatic knees.

Patterns of osseointegration and remodeling in femoral revision with bone loss using modular, tapered, fluted, titanium stems

Radiographic signs of osseointegration with the use of fluted, tapered, modular, titanium stems in revision hip arthroplasty with bone loss have not been previously categorized. Serial radiographs of 64 consecutive hips with mean follow-up of 6.2 years were retrospectively reviewed. Bone loss was classified as per Paprosky classification, osseointegration was assessed according to a modified system of Engh et al, and Harris Hip Score was used to document pain and function. Seventy-four percent of the hips had type 3 or 4 bone loss. All stems were radiographically osseointegrated. Early minor subsidence was seen in 6.2% of the hips; definite bony regeneration, 73% of the hips; and stress shielding, 26% of the hips. These osseointegration patterns were different from those described for extensively porous-coated cobalt-chromium stems and had a bearing on the evaluation of fixation of these stems.

The posterior approach in THR: assuring capsular stability

Repair of the posterior capsule is advocated to reduce dislocation after total hip replacement (THR). To date, no predictable physical findings are reported in the literature to assess the capsular integrity and risk of hip dislocation after the posterior approach. The internal rotation test is performed at 4 to 6 weeks postoperatively with the hip and knee flexed at 90° while the patient is supine. The test is positive if a firm endpoint is felt with internal rotation of ≤15°. Between January 2007 and January 2008, twenty-three patients who had magnetic resonance imaging (MRI) at a mean 1.8±0.7 years after posterior-approach THR were included in this study. Magnetic resonance images were reviewed by a blinded radiologist for the integrity of the posterior capsule and quadratus, the distance between the piriformis and conjoined tendon to bone, and the amount of piriformis obturator internus atrophy. Magnetic resonance imaging results in patients with positive internal rotation tests showed an intact posterior capsule and scarring of the tendons with no severe muscle atrophy. In patients with a negative internal rotation test, MRI showed incomplete healing of the tendons and severe muscle atrophy. Sensitivity and specificity of the internal rotation test for tendon/scar healing were 100% and 93%, respectively. The internal rotation test is a simple, reproducible test that, if positive, has a high correlation with capsule/tendon healing.

Preliminary clinical and radiographic results of large ceramic heads on highly cross-linked polyethylene

Data are limited regarding large ceramic femoral heads with highly cross-linked polyethylene. We hypothesized that large ceramic head articulation with highly cross-linked polyethylene is safe with a low wear rate, comparable to metal-on-highly cross-linked polyethylene.The study group comprised 63 patients (72 hips) who had undergone total hip replacement (THR) with ceramic-on-highly cross-linked polyethylene between April 2006 and March 2007 with a minimum 2-year follow-up. Postoperative Western Ontario and Mc-Master Universities Arthritis Index (WOMAC) and Hospital for Special Surgery (HSS) scores were used for clinical assessment. Six-week and 2-year radiographs were analyzed by 2 independent observers using Roman 1.70 software. Twenty-six patients (29 hips) had 32-mm and 37 patients (43 hips) had 36-mm Biolox delta ceramic femoral heads (Ceramtec, Plochingen, Germany). Mean patient age was 60.9 ± 8.9 years, and mean follow-up was 2.9 ± 0.5 years. Mean postoperative WOMAC and HSS hip scores were 30.4 and 36.6, respectively. Mean wear at 1 and 2 years postoperatively was 0.06 ± 0.28 and 0.006 ± 0.12 mm/yr for all hips, respectively. Mean wear at 1 and 2 years postoperatively for the 32-mm femoral head was 0.063 ± 0.278 and 0.007 ± 0.126 mm/yr, respectively, and for the 36-mm femoral head was 0.057 ± 0.292 and 0.006 ± 0.118 mm/yr, respectively. No patient had any clinical complications, such as reoperation, infection, fractures, or radiographic evidence of osteolysis or loosening. The early results of THR with large ceramic heads demonstrate high safety and efficacy. Our data with 2-year follow-up show low wear rates, similar to published data for metal-on-highly cross-linked polyethylene.

High-flexion total knee replacement: functional outcome at one year

Implants designed for enhanced flexion offer the prospect of improved function after total knee replacement (TKR). Whereas most studies evaluating these implants have focused on the range of knee flexion achieved, this study investigated the quality of function in deep knee flexion. The influences of residual pain and maximum flexion angle on function in deep knee flexion were also examined. Eighty-three patients (100 knees) were prospectively followed for 1 year after TKR with a rotating-platform posterior-stabilized high-flexion prosthesis. Range of motion was measured and Knee Society scores were calculated. A questionnaire evaluated residual knee pain and function in high-flexion activities. Mean Knee Society score was 95, and mean knee flexion was 125°, yet 20% of patients could neither kneel, nor squat, nor sit on their heels. Fifty-seven percent were able to kneel without significant difficulty; 69% were able to squat without significant difficulty; and 46% were able to sit on their heels without significant difficulty. Function in deep flexion correlated with pain scores but did not correlate with knee flexion angles or Knee Society scores. Results 1 year after TKR with a rotating-platform posterior-stabilized high-flexion prosthesis are encouraging, but one in five patients remain significantly limited in high-flexion activities.

Revision total hip arthroplasty for ceramic head fracture: a long-term follow-up

The results of revision total hip arthroplasty (THA) for ceramic head fracture have generally been disappointing, largely due to third body wear after incomplete synovectomy. We have followed 8 patients who sustained ceramic head fractures and were subsequently revised to a metal-on-polyethylene articulation. There were no revisions for osteolysis or aseptic loosening at a mean follow-up of 10.5 years. The yearly wear rates of each of 5 of these THAs after revision were compared with 6 matched metal-on-polyethylene THAs; there were no significant differences in wear rates. Greater than 10-year survivorship with a metal-on-polyethylene bearing couple is possible after revision THA for a ceramic head fracture if a complete and thorough synovectomy can be performed. Our technique of synovectomy will be described.

Extra-articular deformity is always correctable intra-articularly: in the affirmative

Patients with arthritis of the knee and an extra-articular deformity present a unique technical challenge, as it becomes more difficult to restore the mechanical axis during total knee replacement (TKR). Current treatment options include a 2-stage procedure in which an extra-articular correctional osteotomy is performed several months before the primary TKR, a 1-stage procedure in which an extra-articular correctional osteotomy is performed at the time of the index TKR, or a 1-stage procedure in which TKR is performed with correction of the extra-articular deformity. One-stage TKR with intra-articular correction of the extra-articular deformity is our treatment of choice. With proper planning, appropriate bone cuts to restore alignment, and the necessary soft tissue releases to balance the knee in flexion and extension, a satisfactory TKR can be achieved. Two patients with arthritis and a severe extra-articular deformity (varus/valgus deformity >20 degrees , recurvatum and malunion of a tibial or femoral fracture) were treated with 1-stage TKR with intra-articular correction of the extra-articular deformity. The technique followed had been successfully performed in 15 previous cases. The procedure was clinically successful in both patients without complications. At 2-year follow-up, Knee Society Scores improved from 40 to 95 and there was no evidence of instability in either case.

Two-year to five-year follow-up of femoral defects in femoral revision treated with the link MP modular stem

Femoral deficiency has been shown to adversely affect the results of revision total hip arthroplasty. Tapered titanium modular stems allow distal fixation of the fluted, conical portion of the implant in the setting of proximal bone loss. One hundred two consecutive hips with proximal bone loss underwent revision femoral reconstruction between 1998 and 2002 at 3 centers using the Link MP modular stem. Forty-three hips had Mallory type 3C femoral deficiency. Ninety-seven hips were observed for an average of 45 months (range, 24-72; median, 36 months). Clinically, mean Harris hip score improved from 36 to 84 (range, 54-99). Radiographically, 93 hips were considered stable, with no circumferential lucencies at the distal fixation surface. Three hips migrated and required revision, along with one periprosthetic fracture. Five other hips had nonprogressive migration of 1 to 2 mm.

The squeaking hip: a phenomenon of ceramic-on-ceramic total hip arthroplasty

BACKGROUND

Early reports on modern ceramic-on-ceramic total hip replacements have demonstrated excellent clinical and radiographic results with few cases of catastrophic failure, which, in the case of earlier designs, often had been caused by implant fracture. Several reports, however, have noted the presence of audible squeaking. The purpose of the present study was to determine the incidence of squeaking in association with the use of this bearing couple.

METHODS

During the period from March 2003 to May 2005, three surgeons performed 159 total hip arthroplasties in 143 patients with use of a ceramic-on-ceramic bearing. One hundred and forty-nine hips (131 patients) were available for review after at least one year of follow-up. These patients were followed prospectively with use of the modified Hospital for Special Surgery hip score and a patient-administered questionnaire. Additionally, a control group of sixty hips (forty-eight patients) with a metal-on-polyethylene bearing was matched to the ceramic group on the basis of age, sex, and body mass index to compare the incidence of squeaking and other noises. Radiographic evaluations were performed according to previously established criteria.

RESULTS

Fourteen (10.7%) of 131 patients described an audible squeak during normal activities. However, squeaking was reproducible clinically in only four patients, and only one patient complained of squeaking before being presented with the questionnaire. The average Hospital for Special Surgery score improved from 19.8 preoperatively to 38.4 at the time of the latest follow-up, indicating excellent clinical results. Ninety-five percent of the patients had a satisfaction score of > or =8 of 10. Three hips dislocated. One of those three hips squeaked and was revised because of recurrent dislocations. One patient was considering revision because of squeaking. In the matched metal-on-polyethylene cohort, there were no cases of squeaking.

CONCLUSIONS

The squeaking hip is a phenomenon that is unique to total hip replacements with hard-on-hard bearings. The incidence of squeaking in association with ceramic-on-ceramic bearings may be higher than previously reported as <1% of the patients in the present study reported this finding before being queried. The causes and implications of squeaking are yet to be determined. The use of hard-on-hard bearings offers many advantages in terms of wear reduction, especially for young and active patients. Nonetheless, patients considering ceramic-on-ceramic bearings should be counseled with regard to this phenomenon.