Morteza Meftah

Early Corrosion-related Failure of the Rejuvenate Modular Total Hip Replacement

BACKGROUND The Rejuvenate modular-neck stem implant (Stryker Orthopaedics, Mahwah, New Jersey) was recently recalled due to corrosion at the femoral neck-stem junction. The purpose of this study was to investigate the rate of corrosion-related failure and survivorship of this implant and analyze the correlation of implant and patient factors with serum metal ion levels and revisions. METHODS From June 2009 to July 2012, 123 Rejuvenate total hip arthroplasty stems (ninety-seven modular and twenty-six non-modular) were implanted in 104 patients by a single surgeon. Serum cobalt (Co) and chromium (Cr) levels (micrograms per liter [μg/L]) were measured postoperatively for all patients. Patients with persistent hip pain or elevated metal ion levels underwent magnetic resonance imaging for assessment of osteolysis or adverse local tissue reactions. Correlation of implant factors (stem size, head size, head length, and femoral head-neck offset) and patient factors (age, sex, and body mass index) with serum metal ion levels and revisions were analyzed with use of logistic regression models. RESULTS The mean duration of follow-up (and standard deviation) was 2.7 ± 0.6 years. The mean Co and Cr levels were 5.4 ± 5.7 μg/L (range, 0.2 to 31 μg/L) and 2.1 ± 1.5 μg/L (range, 0.1 to 4.3 μg/L), respectively. The differences in Co and Cr levels between the two groups (modular and non-modular) were significant: 48% of the total hip arthroplasties in the modular group resulted in elevated metal ion levels (Co >4.0 μg/L and Cr >2.0 μg/L; p < 0.05). The metal ion levels in the non-modular group were normal. In the modular group, higher metal ion levels were significantly correlated with younger age and a higher femoral head-neck offset (p = 0.04). Pain and high Co serum levels were significant predictors of revision surgery (p = 0.006). The rate of revision at the time of this study was 28% in the modular group, with the majority of the revisions performed in the second year after surgery; the Kaplan-Meier survivorship was 40% at four years. CONCLUSIONS The short-term high rate of corrosion-related revision with Rejuvenate modular-neck stems is striking.

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.

Radiographic Predictors of Hip Pain in Femoroacetabular Impingement

The primary diagnosis of femoroacetabular impingement is based on clinical symptoms, physical exam findings, and radiographic abnormalities. The study objective was to determine the radiographic findings that correlate with and are predictive of hip pain in femoroacetabular impingement (FAI). One hundred prospective patients with unilateral FAI symptoms based on clinical and radiographic findings were included in this study. All patients filled out a WOMAC pain questionnaire. Two independent-blinded surgeons assessed antero-posterior and lateral radiographs for 33 radiographic parameters of FAI. Correlations between pain scores and radiographic findings were calculated. A matched radiographic analysis was performed comparing symptomatic versus asymptomatic hips. Radiograph findings were also compared between males and females. Weak positive correlations were identified between increasing pain scores with radiographic findings of posterior wall dysplasia, presence of a shallow socket, and a more lateral acetabular fossa relative to the Ilioischial line. A symptomatic hip had a lower neck shaft angle, greater distance from Ilioischial line to acetabular fossa and larger distance from cross-over sign to superolateral point of the acetabulum when compared to the asymptomatic hip in the same patient. Symptomatic hips in males had more joint space narrowing, femoral osteophytes, higher alpha angles and larger, more incongruent femoral heads compared to females. Females had more medial acetabular fossa relative to the Ilioischial line and smaller femoral head extrusion index. Similar to other musculoskeletal conditions, radiographic findings of FAI are poor predictors of hip pain.

Management of Modifiable Risk Factors Prior to Primary Hip and Knee Arthroplasty: A Readmission Risk Assessment Tool.

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.

Challenges in outcome measurement: discrepancies between patient and provider definitions of success.

BackgroundSome orthopaedic procedures, including TKA, enjoy high survivorship but leave many patients dissatisfied because of residual pain and functional limitations. An important cause of patient dissatisfaction is unfulfilled preoperative expectations. This arises, in part, from differences between provider and patient in their definition of a successful outcome.Where Are We Now?Patients generally are less satisfied with their outcomes than surgeons. While patients are initially concerned with symptom relief, their long-term expectations include return of symptom-free function, especially in terms of activities that are personally important. While surgeons share their patients’ desire to achieve their goals, they are aware this will not always occur. Conversely, patients do not always realize some of their expectations cannot be met by current orthopaedic procedures, and this gap in understanding is an important source of discrepancies in expectations and patient dissatisfaction.Where Do We Need to Go?An essential prerequisite for mutual understanding is information that is accurate, objective, and relevant to the patient’s condition and lifestyle. This critical information must also be understandable within the educational and cultural background of each patient to enable informed participation in a shared decision making process. Once this is achieved, it will become easier to formulate similar expectations regarding the likely level of function and symptom relief and the risk of adverse events, including persistent pain, complications, and revision surgery.How Do We Get There?Predictive models of patient outcomes, based on objective data, are needed to inform decision making on the individual level. This can be achieved once comprehensive data become available capturing the lifestyles of patients of diverse ages and backgrounds, including data documenting the frequency and intensity of participation in sporting and recreational activities. There is also a need for greater attention to the process of informing patients of the outcome of orthopaedic procedures, not simply for gaining more meaningful consent, but so that patients and providers may achieve greater alignment of expectations and increased acceptance of both the benefits and limitations of alternative treatments.

SPECT/CT in the Management of Osteochondral Lesions of the Talus:

Background: The treatment of osteochondral lesion of the talus (OLT) is mainly based upon the stage of the disease so accurate imaging is crucial. SPECT/CT combines bone scan with high-resolution CT and can provide functional-anatomical images in a single stage. The purpose of this study was to assess the value of SPECT/CT in the management of OLT. Materials and Methods: From 2004 to 2009, 22 patients with OLT were identified that had both SPECT/CT and MRI of the foot and ankle. All charts were reviewed to ascertain the reason for ordering the SPECT/CT and the additional information obtained. AOFAS outcome scores were calculated at the time of followup. Results: Twelve patients underwent ankle arthroscopy for debridement or drilling of the osteochondral lesion. The mean AOFAS score in these 12 patients was 83.6. SPECT/CT helped preoperative planning by identifying the exact location of the active lesion, especially in multifocal disease or revision surgeries while showing the depth of the active lesion. Ten patients had conservative management due to minimal or no activity over the lesion on SPECT/CT images. The mean AOFAS score in these ten patients was 78.8 which was comparable to the operative group. Conclusion: We believe SPECT/CT was able to provide additional diagnostic value by demonstrating a co-existing pathology as a potential cause of pain and in preoperative planning by showing the depth of activity and the precise location of the active segment in multiple lesions. Level of Evidence: III, Retrospective Case Control Study

Cementless fixation in total knee arthroplasty: down the boulevard of broken dreams – affirms

There has been a recent increase in interest for non-cemented fixation in total knee arthroplasty (TKA), however the superiority of cement fixation is an ongoing debate. Whereas the results based on Level III and IV evidence show similar survivorship rates between the two types of fixation, Level I and II evidence strongly support cemented fixation. United Kingdom, Australia, Sweden, and New Zealand registry data show lower failure rates and greater usage of cemented than non-cemented fixation. Case series studies have also indicated greater functional outcomes and lower revision rates among cemented TKAs. Non-cemented fixation involves more patellofemoral complications, including increased susceptibility to wear due to a thinner polyethylene bearing on the cementless metal-backed component. The combination of results from registry data, prospective randomised studies, and meta-analyses support the current superiority of cemented fixation in TKAs.

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.

Properties of the Patient Administered Questionnaires

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.

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.