Prevalence of Postoperative Periprosthetic Femur Fractures Between Two Different Femoral Component Designs Used in Direct Anterior Total Hip Arthroplasty.

BACKGROUND: Periprosthetic femur fractures are a well-documented complication following direct anterior uncemented total hip arthroplasty. The purpose of this study is to compare the prevalence of postoperative periprosthetic femur fractures between 2 different femoral component designs used in direct anterior total hip arthroplasty. METHODS: Beginning in February 2015, a single fellowship-trained adult reconstruction surgeon performed 361 consecutive direct anterior total hip replacements using a flat, single-taper, wedged femoral implant. In June 2016, that same surgeon, using the exact same surgical technique and postoperative weight-bearing protocol, began using a dual-taper, hydroxyapatite-coated implant for 789 consecutive hips. The patients were carefully monitored for 3 months after surgery to identify the frequency of periprosthetic femur fractures. A Fisher's exact test was used to determine if the prevalence of periprosthetic femur fractures differed between the 2 implant designs. RESULTS: Five of 361 (1.4%) patients sustained proximal femur fractures at an average of 19.6 days postoperatively in the first group, all demonstrating a Vancouver type B2 periprosthetic fracture and requiring femoral revision. No patients (0/789, 0%) in the second cohort sustained a postoperative, periprosthetic fracture (P = .006). CONCLUSION: In this comparison of 2 consecutive cohorts, the dual-taper, hydroxyapatite-coated implant had a statistically significant lower postoperative periprosthetic fracture rate than a flat, single-taper, wedged design.

Is Physician Quality Reporting System Worth the Cost to Report to Center for Medicare and Medicaid Services?

BACKGROUND: The Center for Medicare and Medicaid Services (CMS) has proposed a move to payment based on patient-reported outcomes (PROs), and failure to report on PROs will result in a penalty of 2% in 2016. However, the cost to the physician to collect PROs is not known. METHODS: Using data from the 2013 Medical Group Management Association Compensation and Financial survey and Center for Medicare and Medicaid Services reimbursement, a calculation was performed to determine the cost to the physician to report on PROs for patients undergoing total knee arthroplasty and total hip arthroplasty. Using Medical Group Management Association and Medicare fee for service rates, calculations were performed based on an annual volume of 200 Medicare operative cases (125 total knee arthroplasties, 75 total hip arthroplasties) with 1000 new patients (level 4) and 2000 established patients (level 3) visits. A range of start-up and annual costs necessary to collect PROs including hardware, software, and personnel costs was calculated and then compared with the calculated 2% Medicare penalty for failing to report PROs in 2016. RESULTS: The cost to collect PROs ranged from $47,973 to $56,288 which far outweighed the penalty of $2954 in 2016 for failing to report these measures. CONCLUSION: With the move toward requiring surgeons to report PROs for reimbursement, the current financial model would prove to be cost prohibitive and the incentive to report PROs might be too costly to gain wide acceptance.

An Intact Anterior Cruciate Ligament at the Time of Posterior Cruciate Ligament-Retaining Total Knee Arthroplasty Was Associated With Reduced Patient Satisfaction and Inferior Pain and Stair Function.

BACKGROUND: Patients with an intact anterior cruciate ligament (ACL) at the time of ACL-sacrificing total knee arthroplasty (TKA) have been suggested to have inferior outcomes compared with those with a dysfunctional ACL. However, to date, no published clinical studies have evaluated the potential link between the condition of the ACL at the time of posterior cruciate ligament-retaining TKA and postoperative pain, function, and satisfaction. As such, the purpose of this study was to compare subjective function, movement-elicited pain, pain at rest, and patient satisfaction between those with an intact or dysfunctional ACL. METHODS: We identified 562 posterior cruciate ligament-retaining TKAs with complete intraoperative and postoperative data. Patients were categorized based on the condition of the ACL at the time of TKA as either being intact or dysfunctional (absent or lax). Knee Society Function Scores, movement-elicited pain, pain at rest, and patient satisfaction were then compared between groups. RESULTS: At mean follow-up of 5.1 years, a significantly lower proportion of patients in the intact group were satisfied with their operation (intact: 391/453 [86.3%] vs dysfunctional: 102/109 [93.6%], P = .0496). Inspection of the individual activities revealed that the groups did not differ in walking ability or pain when walking; however, the intact group reported significantly reduced ability to navigate stairs with greater pain during that activity. CONCLUSION: The lack of difference in pain at rest between groups suggests that pain and functional impairments during more demanding activities such as navigating stairs may be associated with the lost function of the ACL rather than by altered central pain processing.

Greater Medial Compartment Forces During Total Knee Arthroplasty Associated With Improved Patient Satisfaction and Ability to Navigate Stairs.

BACKGROUND: The purpose of this study was to determine if postoperative patient satisfaction, subjective outcomes, and functional force testing differed between those with symmetric or asymmetric intraoperative mediolateral (ML) compressive forces. We hypothesized that the threshold would be similar to the previously reported valued of 15 lbf and that a significantly greater proportion of those with more symmetrical medial and lateral compressive forces would be satisfied with their total knee arthroplasty. METHODS: A commercially available instrumented trial tibial liner was used to measure ML compressive force differences with the knee at 0°, 20°, and 90°. Patient satisfaction and Knee Society Scores were compared between patients with ML asymmetries above and below the calculated optimal threshold. RESULTS: Surprisingly, lower ML asymmetries in extension were associated with a greater risk of being dissatisfied. Of the 50 total knee arthroplasties, 6 of 23 (26%) with ML force asymmetries <10 lbf were dissatisfied compared with 0 of 27 with ML asymmetries >10 lbf (P = .01). Greater asymmetry was associated with significantly greater gains in EQ-5D scores (P = .05) and pain scores (P = .03) and greater pain relief (P = .006) and reduced impact forces when navigating stairs (P = .05). CONCLUSION: Contrary to our hypotheses, the results of this study support the concept that recreating greater forces in the medial compartment much like that of the native knee may yield improved patient-reported outcomes and increased patient satisfaction. The current results further suggest that recreating greater medial compartment forces may have the greatest affect on more demanding activities such as navigating stairs.

Subchondral Bone Marrow Edema Had Greater Effect on Postoperative Pain After Medial Unicompartmental Knee Arthroplasty Than Total Knee Arthroplasty.

BACKGROUND: Although the relationship between pain and bone marrow edema (BME) in the osteoarthritic knee has been established, little is known about the effect of preoperative BME on postoperative outcomes after knee arthroplasty or if the influence of BME on postoperative outcomes differs between medial unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). The purpose of this study was to compare pain, patient satisfaction, and revision rates between medial UKA and TKA patients with and without magnetic resonance imaging evidence of BME in the proximal tibia. METHODS: We identified 71 patients (72 knees) from our prospective outcomes database with magnetic resonance images taken before undergoing either medial UKA or TKA and recorded the absence or presence of tibial BME. We then compared preoperative and postoperative Knee Society pain scores, patient satisfaction, and revisions between groups of UKA and TKA patients with or without preoperative tibial BME. RESULTS: Pain scores for UKA patients with BME were worse both before and after surgery, whereas TKA patients with BME demonstrated greater postoperative improvements in pain scores when compared to TKA patients without BME. Similarly, significantly fewer UKA patients with BME were satisfied with their procedure than those without BME (8/11, 73% vs 17/17, 100%; P = .05), but BME did not affect patient satisfaction after TKA. CONCLUSION: Preoperative BME did not influence TKA outcomes; however, pain scores for UKA patients with BME were worse both before and after surgery and fewer UKA patients with preoperative tibial BME were satisfied with their surgery.

The Location and Severity of Preoperative Subchondral Bone Marrow Lesions Were Not Associated With Inferior Postoperative Outcomes After Medial Unicompartmental Knee Arthroplasty or Total Knee Arthroplasty.

BACKGROUND: Inferior outcomes for medial unicompartmental knee arthroplasty (UKA) patients with preoperative medial tibial bone marrow lesions (BMLs) were recently reported. The purpose of this study was to compare the location and severity of BML on postoperative outcomes after medial UKA and TKA using a larger sample size and more rigorous magnetic resonance imaging (MRI) evaluation. METHODS: BML were graded on preoperative MRIs from 174 UKAs performed between 2009 and 2013 using the MRI Osteoarthritis Knee Score criteria. Grading was performed by a single evaluator blinded to the patient's outcome. MRIs from a matched group of 174 TKAs were then evaluated. Preoperative and postoperative Knee Society Knee Scores, Pain Scores, and Function Scores (FSs) were then compared between UKA and TKA patients based on the location and severity of BMLs. RESULTS: Overall medial-side BML severity (sum of tibia, femur, and patellar grades) did not affect Pain Score or FS; however, UKA and TKA patients with more severe BMLs had greater preoperative-to-postoperative gains in Knee Society Knee Scores (P = .05). When evaluating individual regions, UKA patients with more severe medial tibial BML had significantly greater gains in FS than those without BML, whereas the opposite was true for TKA patients (P = .02). Similarly, UKA and TKA patients with patellar lesions had greater gains in FS than those without BML (P = .05). Medial femoral BML did not appear to affect outcomes for either UKA or TKA patients. CONCLUSION: Medial tibial BMLs were not associated with inferior outcomes. Clinically, these results suggest that BMLs should not be considered a contraindication for medial UKA.

Comparison of Patient Function during the First Six Weeks after Direct Anterior or Posterior Total Hip Arthroplasty (THA): A Randomized Study.

The purpose of this single-surgeon randomized study was to determine if functional recovery during the early postoperative period differs between the direct anterior (DAA) and posterior approaches (PA). An a priori power analysis indicated that 26 patients per group were needed, and 6-week follow-up data were available for 51 THAs to date. Hospitals stays were significantly shorter for the DAA group (1.4 vs. 2.0 days, P=0.01), and the change in Pain Scores was significantly greater for the DAA group (P=0.04). The DAA group also discontinued use of an assistive ambulatory device at an earlier time (33.0 vs. 43.1 days, P=0.03). Despite these differences, no other subjective or objective functional measures differed between the 2 groups at the 6-week follow-up.

Assessing the utility of routine first annual follow-up visits after primary total knee arthroplasty.

The combination of increased TKA utilization and a decreased number of arthroplasty specialists has resulted in a growing need to maximize efficiency without sacrificing the level of care being provided. The purpose of this study was to evaluate the utility of routine first annual follow-up visits for patients that have undergone primary TKA. Of 339 TKAs performed by a single surgeon in 2012, 23% failed to attend scheduled first annual visits. Furthermore, none of the revisions performed at our facility since 2003 were the direct result of information gained at a patient's routine first annual visit. As such, we question the clinical utility of the first annual visit.

Patients with Pain 60 to 120 Days after Total Knee Arthroplasty More Likely to be Dissatisfied at Mid-Term Follow-Up.

The purpose of this study was to determine if TKA patients with pain between 60 and 120 days are more likely to be dissatisfied at mid-term follow-up. At the 60-120 day follow-up, moderate to severe movement-elicited pain (MEP) and pain at rest (PAR) were reported by 25/316 TKAs (7.9%) and 44/316 TKAs (13.9%), respectively. A greater proportion of those with MEP at 60-120 days were dissatisfied at midterm follow-up (24% vs. 6.5%, P = .01), and those with MEP early after surgery were 4.5 times more likely to be dissatisfied at mid-term follow-up (P = .004). Similarly, those with PAR 60-120 days after surgery were 4.1 times more likely to be dissatisfied at mid-term follow-up (P = .002).

Chronic Non-Orthopedic Conditions More Common in Patients with Less Severe Degenerative Changes That Have Elected to Undergo Total Knee Arthroplasty.

The purpose of this study was to determine whether the prevalence of chronic non-orthopedic conditions that may play a role in an abnormal pain response differs between patients based on the severity of degenerative changes at the time of surgery. Of 1020 OA knees that had undergone primary TKA with a minimum 2year follow-up, we identified 117 (11.5%) that had less severe degenerative changes. The prevalence of dissatisfaction was significantly greater in less severe group compared to those with moderate or severe changes (18.8% vs. 9.3%, P=.003). Chronic non-orthopedic conditions were significantly more prevalent in the less severe group with 41.9% reporting depression/anxiety, 30.8% with fibromyalgia or low back pathology, and 12.8% with a prior traumatic brain injury or stroke.

Factors influencing patient satisfaction two to five years after primary total knee arthroplasty.

Between 15% and 20% of primary total knee arthroplasty (TKA) patients have been reported to be dissatisfied with the procedure. With 2 to 5 year follow-up of 768/959 (80%) cruciate-retaining TKAs performed by a single surgeon, we evaluated the prevalence of dissatisfied patients and determined which factors were most related to patient satisfaction. Of the 768 TKAs, 80 were dissatisfied with their procedure (10.4%). Postoperative Knee Society Pain Scores and passive knee flexion were most related to a lack of satisfaction. Age, gender, and BMI did not appear to be related to patient satisfaction. By and large, dissatisfied patients in the current study had not experienced improvements in passive flexion, Pain Scores, or Function Scores when compared to their preoperative state.

Greater prevalence of wound complications requiring reoperation with direct anterior approach total hip arthroplasty.

The purpose of this retrospective study was to compare wound complication rates between primary THAs performed via a posterior or direct anterior approach. From our prospective outcomes registry, we identified 1288 primary THAs performed via a posterior approach and 505 via a direct anterior approach. The direct anterior approach resulted in a significantly greater number of wound complications that required reoperation than the posterior approach (7/505 (1.4%) vs. 3/1,288 (0.2%), P=0.007). As such, patients should be counseled on the potential increased risk of early wound complications with the direct anterior approach, and future research is needed to determine if alternative closure techniques can reduce the risk of wound complication.

Patient and intraoperative factors influencing satisfaction two to five years after primary total knee arthroplasty.

The purpose of this study was to compare patient demographics and factors recorded at the time of surgery between patients that were either satisfied or dissatisfied with their TKA at mid-term follow-up. From our prospective outcomes database, 989 primary TKAs with complete preoperative and intraoperative data were identified. At mean follow-up of 3.5 years, 94/989 TKAs (9.5%) were not satisfied with their TKA. African American patients were 3.0 times more likely to be dissatisfied than Caucasians (95% CI = 1.5-6.0, P = .003). Patients with less severe degenerative changes were 2.1 times more likely to be dissatisfied (95% CI = 1.3-3.2, P = .001).

Soft tissue releases affect the femoral component rotation necessary to create a balanced flexion gap during total knee arthroplasty.

The structures that were released to balance the extension gap were recorded during 1500 consecutive TKA procedures, and the amount of femoral component external rotation (ER) necessary to balance the flexion gap was measured with a tensiometer. The amount of ER necessary to balance the flexion gap significantly decreased as more medial structures were released (1 structure=4.7°, 2=4.1°, 3=2.8°, 4 or more=1.1°, P<0.012), whereas significantly greater ER was necessary when three or more lateral structures were released (1 structure=5.3°, 2=5.5°, 3 or more=8.6°, P<0.03). Soft tissue releases affected the amount of femoral component ER necessary to balance the flexion gap, bringing into question the ability of techniques utilizing bony landmarks to properly align the femoral component in rotation.

A Medial Subvastus Approach for Lateral Unicompartmental Knee Arthroplasty: Technique Description and Early Outcome Results.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) treats arthritis involving only one compartment of the knee. Lateral UKA is mainly performed through medial parapatellar or lateral parapatellar approaches to the knee. This technique article introduces a medial subvastus approach to lateral UKA, discusses the clinical rationale behind its use, and offers a preliminary retrospective study on short-term outcomes of lateral UKAs using the lateral vs medial subvastus approaches. METHODS: A description of the medial subvastus approach is included. In addition, we reviewed 32 and 30 lateral UKAs performed using the lateral and medial subvastus approaches, respectively. Minimum follow-up duration was 1 year. Knee injury and osteoarthritis outcome score for joint replacement (KOOS, JR) knee scores were used for comparison. RESULTS: Age and body mass index were similar between the 2 cohorts. Mean KOOS, JR. scores for the subvastus approach group were significantly higher than those for the lateral approach group at 81.41 ± 2.0 for medial subvastus and 74.19 ± 2.9 for lateral (P = .02). One deep infection and 2 revision total knee arthroplasties occurred in the lateral approach group. Neither occurred in the subvastus group. The mean follow-up duration was significantly longer for the lateral approach group than that for the subvastus group at 749 vs 410 days (P < .001). Literature on time-dependence of patient-reported outcomes supports usage of the data, despite follow-up discrepancies. CONCLUSIONS: A subvastus approach for lateral UKA may offer improved visualization, easier conversion to total knee arthroplasty, and faster recovery, based on clinical observation. Preliminary results suggest improved short-term knee scores compared to a lateral approach.

Static and mobile antibiotic-impregnated cement spacers for the management of prosthetic joint infection.

Two-stage treatment is currently the most common approach for management of an infected joint prosthesis in the United States. Static antibiotic-impregnated polymethylmethacrylate cement spacers have traditionally been used; increasingly, however, mobile or articulating spacers are being utilized. Advocates of mobile spacers have cited potential advantages, including more effective maintenance of the joint space, allowing for limited weight bearing and facilitating joint motion; possible reduction in bone loss; and local delivery of antibiotics. Because a variety of materials and construction methods is used to make knee and hip spacers, comparisons are difficult. Randomized, prospective studies are needed to determine the best spacers for total knee and total hip arthroplasties.

Correlations between knee society function scores and functional force measures.

Subjective evaluations often are used after knee arthroplasty to quantify function; however, these scores may be influenced by pain and/or function of the nonoperated limb. Multiple influences increase variability of these scores, which in turn may result in a greater change in score required to be considered clinically important. We determined the relationships among the Knee Society pain and function scores, range of motion (ROM), and functional force measures of the surgically treated and nonoperated limbs. Before and 3 months after total or unicompartmental knee arthroplasty, 36 patients answered questions necessary to calculate the Knee Society pain and function scores. A dual-force platform was used to record the lift-up force of each limb during a stepping task. Function scores were correlated to pain scores, lift-up force of the nonoperated limb, and ROM before surgery. After surgery, function scores correlated with pain scores but not with objective functional measures or ROM. As patient-reported function scores and functional force measures of the surgically treated limb seem to provide distinctly different information, both measures may need to be collected after knee arthroplasty to fully understand a patient's functional recovery.

Electromyographic analysis of hip abductor exercises performed by a sample of total hip arthroplasty patients.

Weakness of the hip abductors after total hip arthroplasty may result in pain and/or functional limitation. Non-weight-bearing (NWB) exercises are often performed to target the hip abductors; however, muscle activation of NWB exercises has not been compared to weight-bearing (WB) exercises. Our purpose was to evaluate gluteus medius activation during 2 WB and 2 NWB hip abductor strengthening exercises. Fifteen patients at least 6 weeks post unilateral total hip arthroplasty volunteered for the study. Electromyographic amplitude for each exercise was normalized to each patient's maximal voluntary isometric contraction. There were no significant differences in gluteus medius electromyographic amplitudes between the 4 exercises (P = .15). Based on our results, NWB exercises provided no clear benefit in terms of gluteus medius activation when compared to potentially more functional WB exercises in the early postoperative period.

Progressive subsidence of a tapered, proximally coated femoral stem in total hip arthroplasty.

The purpose of this study was to determine if subsidence of a tapered, proximally porous- and hydroxyapatite-coated femoral implant with immediate postoperative weight-bearing differed between men and women. Modified Harris Hip Pain and Function Scores were collected preoperatively, and six weeks and one year postoperatively. Femoral subsidence was determined at six weeks and one year after surgery. Men demonstrated significantly increased Harris Hip Function Scores at six weeks, with slightly inferior Harris Hip Pain Scores at one year. Regardless of sex, subsidence was greater at one year than at six weeks; however, men subsided significantly more at one year than women (1.7 +/- 2.0 mm vs 1.0 +/- 1.4 mm, p = 0.03). While it appears that this stem provided excellent early fixation in women, it is unclear if the increased subsidence in men was more related to patient-related factors of age, weight and activity level or with specific implant characteristics.

Clinical comparison of THA with a standard-length or short femoral component.

The purposes of this 2-part study were to determine whether reduced distal femoral component geometry allows for routinely larger component sizes to be used and whether clinical or radiographic outcomes differ between total hip arthroplasty (THA) patients treated with either standard-length or short femoral components. Femoral component size and ongrowth surface area were retrospectively compared in a group of bilateral THA patients that had both a standard-length component and a contralateral short component. Then, clinical and radiographic outcomes were compared between matched groups of THA patients that had either a standard-length or short femoral component. The use of the short component resulted in a significantly larger femoral component size being used (P=.01), and the potential ongrowth surface area was significantly larger for the short component than for the standard component (median, 36.69 vs 35.55 cm2; P=.02). In the matched-pairs analysis, no group differences were noted in modified Harris Hip Scores (P=.43) or femoral component subsidence (P=.35), but there was a significantly greater prevalence of radiolucent lines in Gruen zone 8 with the short component (P=.008). The use of a short femoral component was associated with consistently larger component sizes being used, which corresponded with a larger potential ongrowth surface area. Short-term clinical and radiographic outcomes did not differ between standard-length and short femoral components. Studies are necessary to determine whether the increased proximal ongrowth surface area may result in improved long-term fixation or, on the contrary, may increase the risk of periprosthetic fracture.