Faculty Bibliography

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.

There are limited data on the influence of a reduced tourniquet time strategy on the clinical outcome of primary total knee arthroplasty (TKA). The aim of our study was to prospectively compare clinical recovery in two groups of patients undergoing TKA based on differences in tourniquet strategy at the same institution. Group A (40 patients) consisted of TKAs performed by a surgeon using tourniquet from incision to arthrotomy closure, and group B (40 patients) consisted of TKAs performed by another surgeon using tourniquet only during cementation. The surgical technique, implants, perioperative management, and patient demographics were similar between groups. Average tourniquet time was significantly higher in group A (71.7 minutes) as compared with group B (36.8 minutes). The maximum hemoglobin (Hb)/hematocrit (Hct) drop was statistically higher in group B (Hb drop = 3.5 +/- 0.9 g/dL; Hct drop = 11 +/- 3) as compared with group A (Hb drop = 2.9 +/- 0.9 g/dL; Hct drop = 9 +/- 2; Hb drop p = 0.01; Hct drop p = 0.002). There were no significant differences in visual analogue scale pain scores, narcotic consumption, ability to straight leg raise during hospital stay, range of motion (ROM) at discharge, as well as isometric quadriceps strength, ROM, Short Form 36 scores, Knee Society scores at 6 weeks, 3 months, and 1 year follow-up with a similar multimodal pain management protocol. Radiographic analysis revealed no differences in cement penetration around the tibial component in any zone. Four patients developed pulmonary embolism (three in group A, one in group B) and five patients underwent manipulation under anesthesia for stiffness (four in group A, one in group B). Thus, the use of a tourniquet only during cementing in TKA increases the hemoglobin drop and does not significantly influence pain or clinical recovery with available numbers, but was associated with a lower incidence of early complications. It is a learned surgical skill which significantly reduces tourniquet time and achieves a similar quality of cementing.

Patient-specific instrumentation (PSI) in total knee arthroplasty (TKA) has been introduced to obtain consistent alignment, prevent instrumentation of the medullary canal and improve operating room efficiency. This article compares simultaneous bilateral TKA performed with and without the use of PSI in terms of surgical time; blood loss and transfusion requirements; length-of-stay, early thromboembolic events and complication rates. There was a trend to reduced total blood loss (as measured by drop in hemoglobin values) and lower transfusion rate after surgery. Further research in the form of high quality randomized trials and cost-benefit analyses may help in further consolidation of these findings.

Flexion instability in posterior-stabilized total knee arthroplasty is a relatively uncommon but distinct problem that is often underdiagnosed and may require surgical management. This retrospective study evaluated the authors' management strategy and assessed the results of revision surgery. The authors identified 19 knees that underwent revision for isolated flexion instability after primary posterior-stabilized total knee arthroplasty. All patients had typical symptoms and signs of flexion instability, which include diffuse pain, especially when negotiating stairs, a sense of instability without giving way, recurrent joint effusions, and diffuse periarticular tenderness. Knee Society scores were used to assess pain and function. Complete revision was performed in 11 knees, femoral revision with a thicker insert was performed in 1 knee, and isolated tibial polyethylene insert exchange was performed in 7 knees. Postoperatively, all patients reported improvement in instability symptoms and signs associated with improvement in mean Knee Society scores. Revision surgery with careful gap balancing is successful in the management of isolated flexion instability in posterior-stabilized total knee arthroplasty. Isolated tibial polyethylene insert exchange may have a role in selected patients where component malalignment and malrotation is ruled out and a thicker and/or semiconstrained insert can be used, while limiting the resultant flexion contracture to less than 5 degrees .

We compared gait parameters prior to, at 6months and 1year following total hip arthroplasty (THA) performed via direct anterior approach (DAA) and posterior approach (PA) by a single surgeon in 22 patients. A gait analysis system involving reflective markers, infrared cameras and a multicomponent force plate was utilized. Postoperatively, the study cohort demonstrated improvement in flexion/extension range of motion (ROM) (P=0.001), peak flexion (P=0.005) and extension (P=0.002) moments with no differences between groups. Internal/external ROM improved significantly in the DAA group (P=0.04) with no change in the PA group. THA performed via DAA and PA offers similar improvement in gait parameters with the exception of internal/external ROM which might be related to the release and repair of external rotators during PA THA.

BACKGROUND: The direct anterior approach for THA offers some advantages, but is associated with a significant learning curve. Some of the technical difficulties can be addressed by the use of intraoperative fluoroscopy which may improve the accuracy of acetabular component placement. QUESTIONS/PURPOSES: The purposes of this study were to determine if (1) there is decreased variability of acetabular cup inclination and anteversion with the direct anterior approach using fluoroscopic guidance as compared with the posterior approach THA without radiographic guidance; (2) if there is a learning curve associated with achieving accuracy with the direct anterior approach THA. We also wanted (3) to assess the frequency of complications including dislocation with the anterior approach, which initially had a learning curve, and the posterior approach. METHODS: This retrospective, comparative study of 825 THAs (372 posterior THAs without fluoroscopic guidance and 453 direct anterior THAs, performed by one surgeon, focused on a radiographic analysis to determine cup inclination and anteversion on standardized pelvic radiographs using specialized software. The first 100 direct anterior THAs performed while transitioning from the posterior approach to the direct anterior approach were included in the learning curve group. During this learning curve period, the direct anterior approach was used for all patients except those with conversion of previously fixed intertrochanteric or femoral neck fractures to THAs, gluteus medius tears, and obese patients with an immobile abdominal pannus (100 of 127 THAs). Variability of the acetabular component was compared among the posterior group, learning curve group, and direct anterior group. RESULTS: Variances for cup inclination and anteversion were significantly lower in the direct anterior group (19 and 16 respectively, p < 0.01) as compared with the posterior group (50 and 79 respectively).Target inclination and anteversion were achieved better in the direct anterior group (98% and 97% respectively) as compared with the posterior group (86% and 77% respectively) (p < 0.01, OR for inclination = 9.1, 95% CI, 3.5 to 23.4; OR for anteversion = 8, 95% CI, 4 to 16). In the learning curve group, target anteversion achieved (91% of cases) was marginally lower than that of the direct anterior group (p = 0.03; OR = 2.9, 95% CI, 1.1 to 7.3) and target inclination (95%) was similar (p = 0.13). There was one posterior dislocation in the posterior group, two anterior dislocations in the learning curve group, and none in the direct anterior group. CONCLUSIONS: Use of fluoroscopy with the patient in the supine position during direct anterior THA enables intraoperative assessment of cup orientation resulting in decreased variability of acetabular cup anteversion. However, there is a learning curve associated with achieving this accuracy. We could not discern whether this difference was the result of the approach or the use of fluoroscopy in the direct anterior group. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

BACKGROUND: Patellar mobilization technique during total knee arthroplasty has been debated, with some suggesting that lateral retraction, rather than eversion, of the patella may be beneficial. We hypothesized that patients with knees surgically exposed using patellar lateral retraction would have comparable outcomes with patients with knees surgically exposed using patellar eversion. METHODS: After an a priori power analysis, 120 patients with degenerative arthrosis were prospectively enrolled and were randomized to one of two patellar exposure techniques during the primary total knee arthroplasty: lateral retraction or eversion. The primary outcome measure was one-year, dynamometer-measured quadriceps strength. The secondary outcome measures evaluated during hospital stay included the ability to straight-leg raise, visual analog scale in pain, walking distance, and length of stay. The secondary outcome measures that were evaluated preoperatively and through a one-year follow-up included the Short Form-36 Physical Component Summary and Mental Component Summary scores, range of motion, quadriceps strength, and radiographic rate of patella baja and tilt. RESULTS: A mixed-model analysis of variance showed no significant differences between the two groups in the one-year outcome measures. At one year postoperatively, quadriceps strength was not different between groups (p = 0.77), and the range of motion significantly improved (p < 0.01) from preoperative values by a mean value (and standard deviation) of 6 degrees +/- 17 degrees , with no significant difference (p = 0.60) between groups. The Short Form-36 Physical Component Summary score and Mental Component Summary score significantly improved (p < 0.01) for both study groups from preoperatively to one year postoperatively with no significantly different effects between groups (time x group, p = 0.85 for the Physical Component Summary score and p = 0.71 for the Mental Component Summary score), and the scores were not different at one year after surgery. There were no significant differences between groups in the change in frequency of the radiographic patella baja (p = 0.99) or the radiographic patellar tilt (p = 0.77) from before surgery to one year after surgery. CONCLUSIONS: Lateral retraction of the patella did not lead to superior postoperative results compared with eversion of the patella during total knee arthroplasty as evaluated using our primary outcome measure of one-year, dynamometer-measured quadriceps strength or our secondary outcome measures. LEVEL OF-EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND: Newer surgical approaches to THA, such as the direct anterior approach, may influence a patient's time to recovery, but it is important to make sure that these approaches do not compromise reconstructive safety or accuracy. QUESTIONS/PURPOSES: We compared the direct anterior approach and conventional posterior approach in terms of (1) recovery of hip function after primary THA, (2) general health outcomes, (3) operative time and surgical complications, and (4) accuracy of component placement. METHODS: In this prospective, comparative, nonrandomized study of 120 patients (60 direct anterior THA, 60 posterior THAs), we assessed functional recovery using the VAS pain score, timed up and go (TUG) test, motor component of the Functional Independence Measure (M-FIM), UCLA activity score, Harris hip score, and patient-maintained subjective milestone diary and general health outcome using SF-12 scores. Operative time, complications, and component placement were also compared. RESULTS: Functional recovery was faster in patients with the direct anterior approach on the basis of TUG and M-FIM up to 2 weeks; no differences were found in terms of the other metrics we used, and no differences were observed between groups beyond 6 weeks. General health outcomes, operative time, and complications were similar between groups. No clinically important differences were observed in terms of implant alignment. CONCLUSIONS: We observed very modest functional advantages early in recovery after direct anterior THA compared to posterior-approach THA. Randomized trials are needed to validate these findings, and these findings may not generalize well to lower-volume practice settings or to surgeons earlier in the learning curve of direct anterior THA. LEVEL OF EVIDENCE: Level II, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.