What is the Fate of Total Hip Arthroplasty (THA) Acetabular Component Orientation When Evaluated in the Standing Position?

This retrospective study measured the change of the acetabular component orientation between supine and standing radiographs in 113 THA patients and identified the associated anatomical parameters that may help direct pre-operative planning. The mean change of the acetabular component inclination and version from supine to standing was 4.6° and 5.9° respectively (P<0.0001), with 49 (43%) hips showing inclination change >5° and 69 (53%) hips showing version change >5°. Twelve (43%) of 28 'malpositioned' cups became 'well-positioned' and 26 (31%) of 85 'well-positioned' cups became 'malpositioned' upon standing. Changes in inclination were associated with leg length discrepancy and pelvic obliquity; and changes in version were associated with pelvic tilt and pelvic incidence. Standing position and patient factors should be considered when defining "optimal" acetabular orientation.

Increased complication rates after hip and knee arthroplasty in patients with cirrhosis of the liver.

BACKGROUND: Risk stratification is critical in patients with cirrhosis undergoing THAs and TKAs, as they may be more likely to have serious medical and surgical complications. As opposed to the Child-Pugh scoring system, which has limited use for orthopaedic surgeons inexperienced in assessing ascites and hepatic encephalopathy, the Model for End-stage Liver Disease (MELD) is an easily calculated, validated scoring system for severity of liver disease based on common laboratory values; however, its usefulness for predicting complications after elective arthroplasty has not been studied. QUESTIONS/PURPOSES: The purposes of this study were to determine the differences between patients with cirrhosis and control subjects in (1) hospital length of stay, discharge disposition, and readmission within 90 days; (2) early postoperative (90 days) medical complications potentially related to liver disease; (3) surgical complications within 90 days and any time after the procedure; (4) mortality rates after THA and TKA; and in addition, (5) to use the MELD score as a predictor for risk of complications and mortality. METHODS: Institutional database query software used coding data identified 115 patients with liver cirrhosis before having THAs or TKAs from 2000 to 2012 and 115 control subjects without cirrhosis matched by age, sex, procedure, and year of surgery. Early postoperative and longer-term medical and surgical complications were compared. Regression analysis was used to determine a MELD score that predicted greater risk of complications. RESULTS: Compared with matched control subjects, patients with cirrhosis had prolonged length of stay and higher rates of discharge to nursing facilities, readmission in 90 days, and urinary tract infections (p < 0.01), renal failure (p = 0.03), blood transfusions (p < 0.01), gastrointestinal hemorrhage (p = 0.04), dislocations (p = 0.01), infections (p = 0.02), and revisions (p = 0.04) within 90 days. One-year (p = 0.01) and longer-term (p = 0.0002) mortality rates were greater in patients with cirrhosis. A MELD score of 10 or greater predicted a three times increased likelihood (odds ratio [OR]) of any complication (95% CI, 1.28-7.00; p = 0.01) and 4.1 times increased likelihood (OR) of death (95% CI, 1.42-11.86; p < 0.01). CONCLUSIONS: Patients with cirrhosis undergoing THAs and TKAs should be counseled regarding their increased risk of medical complications, surgical complications, and death. A MELD score of 10 or greater is associated with a high rate of complications, although this finding needs further validation because we were unable to control for all medical confounders. LEVEL OF EVIDENCE: Level III, prognostic study. See the Instructions for Authors for a complete description of levels of evidence.

A more reliable method to assess acetabular component position.

BACKGROUND: Acetabular component position is associated with joint function and bearing wear. Current techniques for determining acetabular component version on standard radiographs lack reliability. Other, more consistent techniques are time-consuming and require additional equipment or software. QUESTIONS/PURPOSES: We compared three methods of acetabular component position assessment: (1) Einzel-Bild-Roentgen-Analyse (EBRA), (2) Woo and Morrey, and (3) the new ischiolateral method. PATIENTS AND METHODS: We assessed axial component position for 52 hips, with at least three radiographic series, using EBRA, and on true lateral radiographs using the Woo and Morrey method and a new method that uses the ischium as a skeletal landmark, the ischiolateral method. RESULTS: The mean SDs of the ischiolateral (2.15°) and EBRA (2.06°) methods were lower than that of the Woo and Morrey method (3.65°) but were not different from one another. We observed a SD of greater than 4° in 19 (36.5%) hip series using the Woo and Morrey method, compared to six series (11.5%) for both the ischiolateral and EBRA methods. Twenty-four (12.6%) Woo and Morrey measurements were greater than 4° from the mean for the hip series, compared to seven (3.8%) for ischiolateral and nine (4.7%) for EBRA. The intraclass correlation coefficients for intra- and interobserver reliability for the ischiolateral method and EBRA were the same (0.9). CONCLUSIONS: Referencing the ischium standardizes pelvic position on each lateral radiograph and provides a simple and reliable means to assess axial component position, which is a surrogate for the planar anteversion measured by EBRA.

The role of prehabilitation with a telerehabilitation system prior to total knee arthroplasty.

BACKGROUND: The purpose of the current study was to evaluate the usage of prehabilitation on a telehealth platform prior to total knee arthroplasty (TKA) and its impact on short-term outcomes. Specifically, the study examined whether patients participating in a prehabilitation program impacted length of stay (LOS) and discharge disposition. METHODS: A total of 476 consecutive patients who underwent TKA at three institutions were included. The average age of the 476 patients was 65.1 years (range, 35 and 93 years). There was a total of 114 patients who utilized the novel prehabilitation program that provided exercises, nutritional advice, education regarding home safety and reducing medical risks, and pain management skills prior to surgery. A group of 362 patients who did not utilize the program formed the control cohort. The outcomes evaluated were LOS and discharge disposition to home, home with health aide (HHA), or skilled nursing facility (SNF). RESULTS: The average LOS in the prehabilitation group was significantly shorter than in the control group (2.0 vs. 2.7 days, P<0.001). Additionally, prehabilitation patients had more favorable discharge disposition status in comparison to the control group. In the prehabilitation patients, 77.2% went home without assistance, compared to 42.8% in the control group (P<0.001). Also, significantly fewer patients in the prehabilitation group were discharged to a SNF when compared to the control group (1.8% vs. 21.8%, P<0.0001). CONCLUSIONS: Prehabilitation preceding TKA in the current study showed early benefits in LOS and discharge disposition. This study will help expand the current literature and educate orthopaedic surgeons on a novel technology. To truly appreciate the role of telerehabilitation in the setting of TKA, further investigation is needed to investigate long-term outcomes, cost analysis, and patient and clinician satisfaction.

Complications following tension-band fixation of patellar fractures with cannulated screws compared with Kirschner wires.

BACKGROUND: Displaced patellar fractures are commonly stabilized with a modified anterior tension-band construct. The goal of the current study was to compare the incidence of complications after tension-band fixation of the patella with Kirschner wires as compared with cannulated screws. METHODS: We performed a retrospective cohort study of consecutive, surgically treated patellar fractures. Patients were divided into two cohorts: fractures fixed with use of Kirschner wires and fractures fixed with use of cannulated screws. The primary outcome measure was early loss of fixation that necessitated revision surgery. Secondary outcomes included early postoperative infection and the need for implant removal. RESULTS: Four hundred and forty-eight patellar fractures were studied. Kirschner wires were used for fixation in 315 (70%), and cannulated screws were used for fixation in 133 (30%). The incidence of fixation failure was 3.5% in the Kirschner-wire group and 7.5% in the screw group (p = 0.065). A postoperative infection occurred in 4.4% of patients in the Kirschner-wire group and 1.5% of patients in the screw group (p = 0.17). One hundred sixteen (37%) patients in the Kirschner-wire group and 30 (23%) in the screw group underwent elective implant removal (p = 0.003). After adjusting for confounding variables, a trend toward increased incidence of fixation failure with screws as compared with Kirschner wires was present (p = 0.083). Patients treated with Kirschner wires were twice as likely to undergo implant removal compared with those treated with screws (p = 0.002). CONCLUSIONS: Serious complications are uncommon following treatment of patellar fractures with a modified tension-band technique, with use of either Kirschner wires or cannulated screws. In both groups the rate of fixation failure was low, as was the rate of postoperative infection. Symptomatic implants, the most common complication observed, were twice as frequent in patients treated with Kirschner wires.

Metal-metal reactivity: Houston, we have a problem!

In this single-surgeon series, both resurfaced hips in 1 woman and a total hip arthroplasty in another were revised for symptomatic pseudotumor (3 of 588 hips; 0.51% overall incidence; 2.2% in women). All 3 hips had 50-mm acetabular components. There was no difference in mean lateral opening angle (mean 38.7° vs 42.8° for the others) but these 3 hips all had increased acetabular anteversion (mean 27.1° vs 16.4° for the others; P<.05). Increased combined anteversion is a mechanical common denominator in pseudotumor formation. Female sex and small component size are variables associated with congenital dysplasia, which typically has a small, shallow socket and high combined anteversion. Thus, native anatomy may predispose to the joint mechanics that lead to pseudotumor formation, and not sex or size. The aggregate results indicate that the determination of satisfactory component position includes (1) assessment of the acetabular component lateral opening, (2) acetabular component version, and (3) femoral version. A mechanical problem suggests a mechanical solution. To insure capture of the femoral head by the socket and the intended bearing tribology, acetabular lateral opening angles should be <50°, assuming a femoral neck-shaft angle of 130° to 135°. Combined anteversion should not exceed 40°. In resurfacing of dysplastic cases where the neck-shaft angle exceeds 140°, the acetabular lateral opening angle needs to be correspondingly lower to achieve equivalent head capture and bearing contact.

Surface damage on open box posterior-stabilized polyethylene tibial inserts.

Twenty retrieved Scorpio posterior-stabilized implants were available for analysis. The mean implantation time was 22 months (range, 2 days-42 months). Favorable types and amounts of surface damage were seen on the tibiofemoral and backsides of these modular PE liners that had been packaged in an inert environment and then sterilized by gamma irradiation. Delamination represented only 0.1% of the total surface damage. Off-axis loading (varus malalignment) was associated with tibial component loosening but there was no evidence of peripheral damage of PE caused by edge loading. With this open-box design, hyperextension marks on the anterior aspect of the posterior-stabilized post from femoral component impingement occurred in 11 of 20 cases and was related to sagittal component positioning: excess tibial slope or increased tibial slope combined with a flexed femoral component. Unique coarse abrasions occurred in 16 of 20 cases and were the result of cement extrusion into the open box, especially with varus malalignment. These observations provide guidance for optimizing the surgical technique and the design of posterior-stabilized total knee components.