Taylor Murtaugh

Redefining the Acetabular Component Safe Zone for Posterior Approach Total Hip Arthroplasty

BACKGROUND Acetabular component orientation influences joint stability in total hip arthroplasty (THA). The purpose of this study was to evaluate the effect of cup orientation and other variables on hip dislocation risk and to define a posterior approach specific safe zone. METHODS A cohort of 1289 posterior approach primary THA cases was prospectively followed and component position measured radiographically. RESULTS Cup malposition, with respect to the Lewinnek safe zone, was an independent risk factor for dislocation (OR1.88). Modifying the anteversion safe zone limits to 10-25° strongly predicted increased dislocation risk (OR2.69). No dislocations occurred within a zone defined by a circle centered at 41.4° abduction and 17.1° anteversion, radius 4.3°. CONCLUSION Utilizing a posterior approach specific safe zone of 10-25° anteversion and 30-50° abduction may minimize THA dislocations. LEVEL OF EVIDENCE Level III.

Silver-Impregnated Occlusive Dressing Reduces Rates of Acute Periprosthetic Joint Infection After Total Joint Arthroplasty

BACKGROUND Commercial silver-impregnated occlusive dressings (such as AQUACEL® Ag SURGICAL Cover Dressing) have been touted as antimicrobial dressings to be used following total joint arthroplasty. Given the increased cost of an AQUACEL® Ag SURGICAL Cover Dressing over a standard dressing for total joint arthroplasty, the objective of this study was to determine whether AQUACEL® Ag SURGICAL Cover Dressing is effective in reducing the rates of acute periprosthetic joint infection (PJI) compared to standard sterile dressing. METHODS We retrospectively reviewed the charts of 1173 consecutive patients who underwent a total knee or total hip arthroplasty between 2007 and 2015 by 1 surgeon. The surgeon switched from using a standard xeroform/gauze dressing to an AQUACEL® Ag SURGICAL Cover Dressing in June 2011, with no other major changes in antimicrobial management. Charts were reviewed for evidence of acute PJI (within 3 months of surgery). RESULTS There were a total of 11 cases of acute PJI in this patient cohort (0.94%). The incidence of acute PJI for patients managed with a sterile xeroform dressing was 1.58% (9 of 568 patients), compared to 0.33% (2 of 605 patients) with the use of AQUACEL® Ag SURGICAL Cover Dressing. Univariate analysis showed this to be statistically significant (P = .03), and a multiple logistic regression model supported AQUACEL® Ag SURGICAL Cover Dressing as a protective factor with an odds ratio of 0.092 (95% confidence interval, 0.017-0.490; P = .005). CONCLUSION This 4-fold decrease in acute PJI with the use of AQUACEL® Ag SURGICAL Cover Dressing supports the use of silver-impregnated occlusive dressings for the reduction of acute PJI.

Treatment of Periprosthetic Knee Infection With Concurrent Rotational Muscle Flap Coverage Is Associated With High Failure Rates

BACKGROUND Soft-tissue deficiency is a potentially devastating complication of the infected total knee arthroplasty (TKA). Rotational muscle flaps are commonly used to address these defects. However, reported success rates vary widely. METHODS We reviewed 26 consecutive patients who underwent rotational muscle flap surgery for full-thickness anterior soft-tissue defect during treatment of an infected TKA. Twenty-four cases used a medial gastrocnemius rotational flap, 1 used a lateral gastrocnemius flap, and 1 used a rectus femoris-vastus intermedius flap. Implant survival, recurrence of infection, and limb survival were reported. Patient and procedural characteristics were tested for association with failure using χ2 and Student t-test. Kaplan-Meier analysis was used to estimate the failure-free survival function. RESULTS Mean follow-up time was 3.3 years. Eighteen of 26 patients (69.2%) experienced recurrent infection requiring an average of 5.3 additional operations (range, 1-20). Five (19.2%) required arthrodesis while 6 (23.1%) eventually underwent above-the-knee amputation. Two patients (7.7%) died due to complications of revision surgery or persistent infection. Eleven patients (42.3%) were infection free with a retained prosthesis after treatment at a mean follow-up of 5.3 years (range, 0.7-18.0 years). CONCLUSION Rotational muscle flap coverage of soft-tissue defects in the setting of the infected TKA remains a viable salvage option. However, despite adequate tissue coverage, many patients experience recurrent infection requiring additional surgical treatment. Patients and surgeons should be aware of the potential high failure rates observed when treating these complex problems.

Risk factors for conversion surgery to total hip arthroplasty of a hemiarthroplasty performed for a femoral neck fracture

INTRODUCTION The purpose of this study was to determine risk factors for conversion to total hip arthroplasty (THA) in patients originally treated with hemiarthroplasty (HA) for displaced femoral neck fractures. METHODS In this case-controlled study, we identified 54 patients who were treated with HA for femoral neck fracture (FNF) who subsequently underwent conversion to THA at our institution between 2003 and 2013. We randomly selected 142 control patients who underwent HA for a displaced FNF without conversion surgery during the same time period. We compared demographic data, implant parameters, and radiographic data between the groups to identify risk factors for conversion surgery. RESULTS In the univariate analysis, younger age at index surgery (mean 75 vs. 80 years, p = 0.006), higher body mass index (26.1 vs. 23.7, p = 0.031), bipolar prosthesis (20% vs. 36%, p = 0.024), absence of dementia (6% vs. 23%, p = 0.01), increased leg length compared to contralateral limb (6.5 mm vs. 0.2 mm, p<0.001), and increased HA femoral head size compared to the contralateral femoral head (2.7 mm vs. 1.5 mm, p = 0.02) were associated with a significantly increased risk of conversion surgery. In the multivariate logistic regression, decreased age at index surgery, no dementia, use of a bipolar head, and increased leg length discrepancy (LLD) were associated with risk of conversion. CONCLUSIONS Patient characteristics, including younger age, increased BMI, and absence of dementia can lead to increased risk for conversion of HA to THA. Intraoperative considerations of head size and increase in ipsilateral LLD may increase the risk of conversion surgery. These factors should be considered by surgeons who employ HA for displaced FNFs.

Tranexamic acid increases early perioperative functional outcomes after total knee arthroplasty

Background The purpose of this study was to investigate the influence of tranexamic acid (TXA) on functional outcomes in the immediate postoperative period after total knee arthroplasty (TKA). We hypothesized that the known benefits of TXA would confer measurable clinical improvements in physical therapy (PT) performance, decrease pain, and decrease hospital length of stay (LOS). Methods We retrospectively analyzed 560 TKA patients, including 280 consecutive patients whose surgery was performed before the initiation of a standardized TXA protocol and the first 280 patients who received TXA after protocol initiation. Outcome measurements included postoperative changes in hemoglobin and hematocrit, LOS, pain scores, destination of discharge, and steps ambulated with PT over 5 sessions. Results TXA administration resulted in less overall drops in hemoglobin (P < .001) and hematocrit levels (P < .001). Moreover, patients administered TXA ambulated more than their counterparts during every PT session, which was statistically significant during the second (P = .010), third (P = .011), and fourth (P = .024) sessions. On average, the TXA cohort ambulated 20% more per PT session than patients who did not receive TXA (P < .001). TXA administration did not influence pain levels during PT, hospital LOS, or discharge destination in this investigation. Conclusions It is well known that TXA reduces postoperative anemia, but this study also demonstrates that it confers early perioperative functional benefits for TKA patients. Potential mechanisms for this benefit include reduced rates of postoperative anemia and reduced rates of hemarthroses.