Can Preoperative Factors Be Used to Determine Optimal Implant Design for Total Knee Arthroplasty?

INTRODUCTION: Although studies have demonstrated similar outcomes between ultracongruent (UC) and traditional bearings, debate exists regarding the optimum bearing surface. We sought to determine whether preoperative factors may predict use of a UC bearing when compared to a standard cruciate retaining (CR) group. MATERIALS AND METHODS: The study cohort consisted of 117 patients who underwent primary total knee arthroplasty (TKA). The implants utilized were either the CR or UC polyethylene components of the Zimmer Persona® Total Knee System. Patient demographics and comorbidities were documented. Intraoperative variables and postoperative outcomes were recorded. We calculated change in tibial slope and femoral condylar offset from pre- to post-surgery and computed the percentage of patients for whom an increase in tibial slope or femoral condylar offset was determined. All dependent variables were compared between patients who received the UC component and those with a CR component using either independent samples t-tests or chi-square test of independence. RESULTS: Thirty-nine patients received a UC insert and 78 patients received a CR insert. Mean length of stay (p=0.017), estimated blood loss (p=0.021), and tourniquet time (p=0.032) were greater for the UC group. Intraoperative implant variables were not different between the groups. However, the proportion of patients for whom tibial slope increased postoperatively was greater for the UC group compared to the CR group (p=0.018). CONCLUSION: Our results showed that no preoperative medical comorbidities or demographic factors predicted use of the UC bearing; however, postoperative tibial slope was increased for a greater number of patients who received the UC implant.

What Is the Association Between Articular Cartilage Damage and Subsequent THA 20 Years After Hip Arthroscopy for Labral Tears?

BACKGROUND: Few studies have examined long-term outcomes for patients after arthroscopic treatment for intraarticular hip conditions, and none have done so beyond 10 years postarthroscopy. Examining outcomes beyond 10 years is necessary to determine factors that contribute to conversion to THA in patients undergoing hip arthroscopy for labrochondral damage. QUESTIONS/PURPOSES: (1) What is hip survivorship free from THA in patients who underwent arthroscopic labral débridement, with or without chondroplasty at least 15 years before? (2) What factors are associated with conversion to THA after arthroscopic labral débridement, with or without chondroplasty? (3) Can these data be used to estimate the risk of conversion to THA based on patient- and hip-related factors? METHODS: Between 1989 and 2000, one surgeon performed 552 arthroscopic hip procedures for symptomatic labral tears, with or without associated articular cartilage damage. Of these, the hip status was known in 404 hips (73%) at a minimum of 15 years after the index procedure, with 20 of those patients having died during the followup period. During the study period, patients were offered hip arthroscopy for labral tears with mechanical symptoms, with or without underlying articular cartilage damage. Patient age, sex, acetabular and femoral head Outerbridge grade at surgery, and presence of labral tear were recorded. We determined survivorship free from THA using a Kaplan-Meier survivorship estimator. A stepwise multivariable logistic regression analysis was conducted to determine factors associated with the eventual conversion to THA after hip arthroscopy for labrochondral injuries. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated for all significant independent factors. Odds ratios for combinations of significant factors were used to create a risk assessment. RESULTS: The survivorship free from conversion to THA at 20 years was 59% (95% CI, 53-64. Factors that affected survival included age ≥ 40 years and the presence of combined femoral head and acetabular chondral damage. After controlling for confounding factors, we found that age ≥ 40 years (OR, 2.0; 95% CI, 1.2-3.4; p = 0.011), the absence of all chondral damage (OR, 0.1; 95% CI, 0.03-0.32; p < 0.001), the presence of acetabular damage with severe femoral head damage (OR, 5.0; 95% CI, 2.4-10.3; p < 0.001), and the presence of severe acetabular damage with femoral head damage (OR, 3.7; 95% CI, 2.0-6.8; p < 0.001) were associated with conversion to THA at long-term followup. Based on the calculated ORs, the probability of conversion to THA by 20 years postarthroscopic treatment for labrochondral injuries ranged from 12% (95% CI, 8-17) for a patient younger than 40 years with a Grade 0-II femoral and acetabular Outerbridge grade to 92% (95% CI, 86-95) for a patient older than 40 years with a Grade III-IV femoral and acetabular Outerbridge grade. CONCLUSIONS: Our study revealed that survivorship free from THA at 20 years after arthroscopic labral débridement was associated with both patient age at time of index procedure and, more importantly, the presence of combined femoral head and acetabular chondral damage. Patients should be counseled as to the increased probability of conversion to THA, depending on the health of their articular cartilage after surgery. Future studies should examine survivorship free from THA or clinical symptoms in patients undergoing hip arthroscopy with bone reshaping procedures or with labral repair or reconstruction up to and exceeding 20 years. LEVEL OF EVIDENCE: Level III, therapeutic study.

Treatment for Chronic Hepatitis C Prior to Total Hip Arthroplasty Significantly Reduces Periprosthetic Joint Infection.

BACKGROUND: Patients with chronic hepatitis C (HCV) have had extremely high complication rates after total hip arthroplasty (THA). We sought to compare perioperative complication rates between untreated and treated HCV in THA patients and to compare these rates between patients treated with 2 different therapies (interferon vs direct antiviral agents). METHODS: A multicenter retrospective database query was used to identify patients diagnosed with HCV who underwent THA between 2006 and 2016. All patients (n = 105) identified were included and divided into 2 groups: untreated (n = 63) and treated (n = 42) HCV; treated patients were further subdivided into those receiving interferon (n = 16) or direct antiviral agent therapies (n = 26). Comparisons between the treated and untreated groups were made with respect to demographic data, comorbidities, preoperative viral load, Model for End-Stage Liver Disease score, and all surgical and medical complications; a subgroup analysis of the treated patients was also performed. Separate independent t-tests or Mann-Whitney U tests were conducted for continuous variables. Categorical variables were compared using the chi-squared test of independence. RESULTS: A greater number of untreated patients were human immunodeficiency virus infected (P = .01), while a reduced number of treated patients were either former or current smokers (P = .004). The untreated group had greater surgical complication rates (25.4% vs 4.8%; P = .007), with a higher rate of periprosthetic joint infection (14.3% vs 0%, P = .01). For treated patients, no differences were observed between treatment types for postsurgical complications. CONCLUSION: Treatment for HCV prior to THA appears to be associated to fewer postoperative complications, primarily periprosthetic joint infection. Although further investigation is warranted, strong consideration should be given to treating patients for HCV prior to elective THA.

Characterization of Post-Operative Opioid Use Following Total Joint Arthroplasty.

BACKGROUND: The purpose of our study is to examine post-operative opioid use in total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients and describe factors associated with the need for refill prescriptions. METHODS: Using online prescription information, we calculated the number of filled prescriptions, total morphine equivalent dose (MED) and quantity of pills, and date of last opioid prescription (days) for 197 TKA and 186 THA patients. Patients were classified based on refill status. Opioid data were compared between TKA and THA patients. Relationships between comorbidities and refill status were examined. RESULTS: Number of prescriptions (P < .001), total quantity (P < .001) and MED (P < .001), and days on opioids (P < .001) were greater for TKA patients. TKA patients required more refills (P < .001) for a greater quantity of pills (P = .007). The presence of a comorbidity (P = .003) or anxiety/depression (P = .004) were correlated with refills for TKA patients only. A comorbidity increased the risk of refills by 3.1 times, while anxiety/depression had a 2.5 times greater risk of refills. CONCLUSION: Compared to THA patients, TKA patients were twice as likely to require refill opioid prescriptions and were prescribed a greater total MED for a longer period of time post-operatively. Patients undergoing TKA who present with a comorbidity or are currently being treated for anxiety or depression are more likely to require a refill.

Do Neuromuscular Alterations Exist for Patients With Acetabular Labral Tears During Function?

PURPOSE: To determine if contact forces and electromyography (EMG) muscle amplitudes were altered during the lunge for patients with symptomatic labral tears compared with asymptomatic control subjects. METHODS: Surface electromyography electrodes were placed over the gluteus medius, gluteus maximus, adductor longus, and rectus femoris muscles of the patients' involved limb and matched limb of asymptomatic controls. Subjects performed 3 trials of the lunge on a clinical force platform. An electrogoniometer tracked knee flexion motion during testing. Average root mean squared EMG muscle amplitudes for each muscle were calculated for the descent and ascent phases of the lunge, represented as a percentage of maximum activity (%MVIC). Peak knee flexion was calculated from the goniometer (°). The dependent variables from the force platform were lunge distance (%height), contact time (seconds), vertical impact force (%BW), and force impulse (%BW*s). Dependent variables were compared between groups using either independent samples t tests or Mann-Whitney U tests. Relations between dependent variables were assessed with Spearman Rho correlation coefficients. The level of significance was set at P ≤ .05. RESULTS: Twenty-one patients with symptomatic unilateral labral tears (14 females, 7 males) and 17 asymptomatic control subjects (11 females, 6 males) participated in this study. Average gluteus maximus EMG muscle amplitudes were reduced for symptomatic labral patients compared with asymptomatic controls during lunge ascent (51.6 ± 31.1 v 71.7 ± 36.3 [mean difference (MD): 20.1% (-2.4%, 42.6%)], P = .042). Average vertical impact force was reduced (21.8 ± 5.5 v 26.8 ± 7.3 [MD: 5.1%BW (0.84%BW, 9.3%BW)], P = .02) and average contact time (1.8 ± 0.4 v 1.5 ± 0.4 [MD: 0.27 seconds (0.006 seconds, 0.54 seconds)], P = .045) and force impulse (188.4 ± 42.4 v 162.6 ± 33.3 [MD: 25.8%BW*s (0.3%BW*s, 51.4%BW*s)], P = .042) were increased for symptomatic labral patients compared with asymptomatic controls. Vertical impact force was inversely correlated with gluteus medius muscle amplitudes during lunge descent for symptomatic labral patients (r = -0.452, P = .045). CONCLUSIONS: Our study shows that contact forces and EMG muscle amplitudes are altered during the lunge for patients with symptomatic labral tears. The presence of a relation between muscle amplitudes and contact forces suggests that targeting muscle impairments may restore function in these patients. LEVEL OF EVIDENCE: Level III, case-control study.

Preoperative erythropoietin alpha reduces postoperative transfusions in THA and TKA but may not be cost-effective.

BACKGROUND: Preoperative erythropoietin alpha (EPO) has been shown to be effective at reducing postoperative blood transfusions in total hip arthroplasty (THA) and total knee arthroplasty (TKA); however, treatment with EPO is associated with additional costs, and it is not known whether these costs can be justified when weighed against the transfusion reductions achieved in patients who receive the drug. QUESTIONS/PURPOSES: The purpose of this study is to investigate (1) efficacy of preoperative EPO in reducing postoperative transfusions in TKA and THA; (2) whether patients treated with EPO have reduced length of stay or a different discharge disposition; and (3) whether EPO use reduces overall blood management costs. METHODS: Patients undergoing primary THA or TKA over a 10-month period with preoperative hemoglobin<13 g/dL were recommended to be treated preoperatively with EPO. During that time, 80 of 286 (28%) patients met that inclusion criterion and the treating team recommended EPO to all of them; of that group, 24 (30%) opted to take EPO and 56 (70%) opted not to. Patients receiving at least one dose of EPO and those not receiving EPO were compared in terms of transfusion frequency, length of stay and discharge disposition, and overall blood management costs. Demographics, preoperative hemoglobin, and operative blood loss for both groups were similar (p>0.05). No transfusion triggers were used; rather, patients with postoperative hemoglobin<10 mg/dL and who were symptomatic despite fluid boluses were transfused. The clinician responsible for transfusing symptomatic patients was blinded to the patient's EPO treatment status. Costs were defined as direct costs paid or incurred by our institution for EPO, allogeneic blood, and variable costs associated with patient care after THA/TKA. A decision-tree cost analysis was performed using the collected clinical data and cost data collected from our institution; the analysis considered total associated blood management cost for an EPO and a non-EPO strategy with sensitivity analysis of key cost variables. RESULTS: The proportion of patients receiving transfusions was lower in patients who received EPO than in patients who did not (0% [zero of 24] versus 41% [23 of 56]; p<0.001). The mean length of inpatient hospital stay (EPO: 3.0±0.4 versus control: 3.3±0.8 days, p=0.77) and discharge disposition also was not different between the groups. The cost analysis demonstrated that the EPO strategy was more costly compared with no EPO (USD 2632 versus USD 2284) and its cost would need to be less than USD 225/dose for this to change. CONCLUSIONS: EPO reduced the need for postoperative transfusions in high-risk patients undergoing THA and TKA; however, it was not found to be cost-effective in our model. Our model could not consider relatively rare complications of blood transfusions, including disease transmission, deep periprosthetic infections, and transfusion reactions, but if surgeons or patients value avoiding these potential but rare factors highly, this could reasonably influence the decision of whether to use EPO despite our findings that it was not cost-effective. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Femoroacetabular impingement negates the acetabular labral seal during pivoting maneuvers but not gait.

BACKGROUND: Experimental disruption of the labrum has been shown to compromise its sealing function and alter cartilage lubrication. However, it is not known whether pathological changes to the labrum secondary to femoroacetabular impingement (FAI) have a similar impact on labral function. QUESTIONS/PURPOSES: Does damage to the labrum occurring in association with abnormal femoral morphology affect the labral seal? METHODS: Using 10 fresh cadaveric specimens (mean age 50 years, ±8), we measured the capacity of the central compartment of the hip (the iliofemoral joint) to maintain a seal during fluid infusion, which may help elucidate the function of the labrum during weightbearing. Specimens with and without abnormal femoral morphology (six normal-appearing specimens and four whose geometry suggested cam-type FAI) were tested in postures observed during functional activities, including simulations of normal gait, stooping, and pivoting. Each specimen with FAI morphology exhibited secondary damage of the labrum and the adjacent chondral surface, whereas specimens of normal morphology were undamaged. RESULTS: Average peak central compartment pressure was reduced during pivoting for specimens with the presence of labral damage secondary to FAI. When placed in pivoting positions, hips with FAI maintained lower fluid pressures within the central compartment compared with intact specimens (15±3 versus 42±8 kPa, respectively; effect size: 1.08 [-0.36 to 2.31]; p=0.007). No differences in peak pressure were observed between groups (FAI versus normal) for postures simulating either gait (21±6 versus 22±4 kPa; p=0.902) or stooping (9±2 versus 8±3 kPa; p=0.775) with the numbers available. CONCLUSIONS: The acetabular seal, quantified by the maximum intraarticular pressure, was reduced during pivoting; however, the seal was maintained during simulated gait and stooping. CLINICAL RELEVANCE: Because degeneration is progressive with repetitive impingement, loss of the labral seal starts to be seen during pivoting and may progress from there, but in this small-sample cadaver study that evaluated specimens in middle adulthood, the seal remains intact during simulated gait and stooping. Our study suggests that labral damage secondary to cam-type FAI may reduce the ability of the labral to provide an adequate seal of the central compartment of the hip during loading; however, the extent to which this is affected requires further investigation.

Cartilage Status at Time of Arthroscopy Predicts Failure in Patients With Hip Dysplasia.

The purpose of our study was to determine whether chondral damage at the time of arthroscopy predicted conversion to THA in patients with dysplasia. We identified 166 patients with dysplasia who underwent hip arthroscopy. Forty-seven went on to receive THA. The articular cartilage of three regions of the acetabulum and femoral head were assessed for signs of chondral damage (absent, mild, or severe]). A stepwise multivariable logistic regression analysis revealed mild damage on the posterior femoral head (P=0.001) and severe damage on the anterior acetabulum (P=0.007) made a significant contribution to the predictor. The presence of mild posterior femoral head chondral changes was indicative of more global cartilage damage in this series of patients. Our findings show that chondral damage on the posterior femoral head and anterior acetabulum is a strong predictor of ultimate conversion to THA in dysplastic patients.

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

BACKGROUND: Some 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.

Opioid over-prescription after total joint arthroplasty: Findings from patient reported opioid consumption journals.

We sought to determine postoperative opioid consumption for opioid-naïve patients undergoing total knee and hip arthroplasty (THA and TKA) procedures via an observational cohort study, consisting of 55 patients who underwent either primary unilateral TKA (n = 28) or THA (n = 27). Patients were provided with a journal to track daily consumption of pain medicine. Patients were prescribed an average of 67 opioid pills post-operatively; however, they consumed an average of 31 pills (214 morphine equivalent doses - MED). TKA patients received (p = 0.01) and consumed (p = 0.005) higher amounts of opioids. On average, patients ceased opioid usage at 14 days post-operatively.

Early post-operative opioid consumption: A comparison between medial unicompartmental, patellofemoral, and total knee arthroplasty.

BACKGROUND: While there is emerging literature describing the use of narcotics for post-operative pain control following TKA, little data is available regarding narcotic use in partial knee replacements. The aim of this study is to compare the early post-operative narcotic requirements after medial compartmental arthroplasty (UKA) and patellofemoral arthroplasty (PFA) with that of TKA. METHODS: In this retrospective chart review, we identified 37 patients who underwent PFA and 71 patients who underwent UKA. We identified a cohort of TKA patients who were matched to the unicompartmental group based on sex and age (n = 108). The primary outcome measure was self-reported use of opioids for pain management at the first post-operative clinic visit. Opioid use between groups was compared using Chi-square analysis. RESULTS: The PFA group was younger (p < 0.001) and consisted of more females (p < 0.001) than the UKA group. The UKA cohort had more non-smoking patients (p = 0.044) compared to the PFA cohort. Self-reported opioid use at the first post-operative visit differed between the three groups of patients (p < 0.001). A greater proportion of both PFA (38% vs. 11%; p < 0.001) and TKA (41% vs. 11%; p = 0.01) patients reported opioid use when compared to UKA patients. No differences in opioid use existed between TKA and PFA groups (p = 0.61). CONCLUSION: The prevalence of PFA patients who report opioid use at the first post-operative visit is similar to that for patients following TKA, suggesting that pain management protocols for this specific subset of partial knee arthroplasty patients should be structured similar to TKA patients and separate from UKA patients.

Protocol for a randomised trial evaluating the comparative effectiveness of strategies to promote shared decision making for hip and knee osteoarthritis (DECIDE-OA study).

INTRODUCTION: There are several different interventions available to promote shared decision making (SDM); however, little is known about the comparative effectiveness of different approaches. OBJECTIVE: To examine the impact of patient-directed and physician-directed decision support strategies on the quality of treatment decisions for hip and knee osteoarthritis (OA). TRIAL DESIGN: A 2×2 factorial randomised controlled trial. SETTING: One academic medical centre, one community hospital and one orthopaedic specialty hospital. PARTICIPANTS AND INTERVENTIONS: The enrolment targets were 8 surgeons and 1120 patients diagnosed with hip or knee OA. Patients were randomly assigned to receive one of two different decision aids (DAs) stratified by site. The DAs varied in length, content and the level of detail regarding treatment options. Both DAs were available by paper or online.Surgeons were randomly assigned to receive a report detailing patients' goals and treatment preferences at the time of the visit or not. Eligible patients received their assigned DA before their visit and completed three surveys: before the visit (timepoint (T)1), 1-week postvisit (T2) and 6 months from either the visit date or surgery date for patients who underwent surgery (T3). Study staff and participating surgeons were not blinded, but the statistician conducting the analyses was blinded to the arms. MAIN OUTCOME MEASURE AND ANALYSIS: The primary study outcome was decision quality, the percentage of patients who were well informed and received their preferred treatment. Secondary outcomes included involvement in decision making, surgical rates, health outcomes, decision regret and satisfaction. A logistic regression model with the generalised estimating equations approach was used to compare rates of decision quality between the groups and account for the clustering of patients within providers. ETHICS AND DISSEMINATION: Ethics approval was obtained through the institutional review board at the main site. The findings will be published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT02729831; Pre-results.

Laboratory Tests for Diagnosis of Chronic Periprosthetic Joint Infection Can Help Predict Outcomes of Two-Stage Exchange.

BACKGROUND: Although 2-stage exchange arthroplasty is the most effective treatment among available strategies for managing chronic periprosthetic joint infection (PJI), rates of its success vary greatly. The purpose of our study was to examine whether objective measurements collected at the time of the diagnosis of PJI could be used to identify patients at risk of failure of 2-stage exchange. METHODS: We identified 205 patients across 4 institutions who underwent 2-stage exchange arthroplasty for the treatment of PJI following total hip or total knee arthroplasty. Demographic, surgical, and laboratory data were obtained for each patient from their medical chart. Laboratory values included serum erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP) level, synovial fluid white blood-cell (WBC) count and neutrophil percentage, synovial fluid and/or tissue culture, and Gram stain. Patients who underwent revision surgery for recurrent infection were considered to have failed the 2-stage procedure. Demographic, surgical, and laboratory variables were compared between the 2 groups. Receiver operating characteristic (ROC) curves were constructed to determine threshold cutoffs for significant laboratory values. Risk ratios and 95% confidence intervals were calculated. RESULTS: Overall, 2-stage exchange was unsuccessful for 27.3% of the patients. Preoperative serum ESR (p = 0.035) and synovial fluid WBC count (p = 0.008) and neutrophil percentage (p = 0.041) were greater in patients with recurrent infection. ROC curve analysis revealed a threshold of >60,000 cells/µL for synovial fluid WBC count, >92% for synovial fluid WBC neutrophil percentage, and >99 mm/hr for serum ESR. Failure of 2-stage exchange was 2.5 times more likely for patients with an elevated preoperative synovial fluid WBC count, 2.0 times more likely for those with an elevated preoperative synovial fluid WBC neutrophil percentage, and 1.8 times more likely for those with an elevated preoperative serum ESR. CONCLUSIONS: Our results demonstrated that a greater number of patients in whom 2-stage exchange arthroplasty ultimately failed had a preoperative synovial fluid WBC count of >60,000 cells/µL, a synovial fluid WBC neutrophil percentage of >92%, or a serum ESR of >99 mm/hr. Patients with elevated laboratory values had 1.8 to 2.5 times the risk of treatment failure. These data can serve as a clinical guideline to identify patients most at risk for failure of 2-stage exchange. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Assessing outcomes following arthroscopic labral debridement-what can the IHOT-33 reveal?

As the complexity of arthroscopic procedures continues to increase, assessing the success of these procedures is of utmost importance to determine appropriate treatment plans for patients. This study compares outcome scores on the International Hip Outcome Tool (IHOT-33) using an analysis of its four subscales to scores on the Modified Harris Hip Score (MHHS) in patients following hip arthroscopy. Patients who had undergone hip arthroscopy between 1 and 5 years ago were assessed using both the IHOT-33 and MHHS at their most recent follow-up visit. Total scores for each outcome measure were calculated. A composite score for each of the IHOT subscales was calculated by averaging the total points in each section. Total score on the MHHS was compared with total score on the IHOT-33 and its four subscales using separate wilcoxin signed ranks tests. In total, 44 patients met our inclusion criteria with an average follow-up of 24.8 ± 18.8 months. MHHS total score was greater than IHOT-33 total score (P = 0.04). Comparisons between MHHS total score and the IHOT-33 subscales revealed reductions in sport (P = 0.001) and social (P = 0.004), but no difference in symptoms (P = 0.74) and job (P = 0.84). Our findings demonstrated that scores on the MHHS are inflated when compared with scores on the IHOT-33 for patients following hip arthroscopy. Subscale analysis revealed that the reductions in IHOT-33 scores exist in the sport and recreational domain and social, emotional, lifestyle domain compared with the MHHS. Our results suggest that analysing the subscales of the IHOT-33 would provide a more thorough understanding of functional limitations in patients undergoing hip arthroscopy.

The acetabular labrum regulates fluid circulation of the hip joint during functional activities.

BACKGROUND: An assessment of the effect of surgical repair or reconstruction on the function of the hip labrum is critical to the advancement of hip preservation surgery; however, validated models of the hip that allow the quantification of labral function in functional joint positions have yet to be developed. PURPOSE: To evaluate (1) whether intra-articular pressures within the hip are regulated by fluid transport between the labrum and femoral head and (2) whether the sealing capacity of the labrum varies with joint posture. STUDY DESIGN: Descriptive laboratory study. METHODS: The sealing ability of the hip labrum was measured during fluid infusion into the central compartments of 8 cadaveric specimens. Additionally, the pathway of fluid transfer from the central to the peripheral compartment was assessed via direct visualization in 3 specimens. The effect of joint posture on the sealing capacity of the labrum was determined by placing all 8 specimens in 10 functional postures. The relationship between pressure resistance and 3-dimensional motion of the femoral head within the acetabulum was quantified using motion analysis and computer modeling. RESULTS: Resistance to fluid transport from the central compartment of the hip was directly controlled by the labrum during loading. Maximum pressure resistance was affected by joint posture (P = .001). Specifically, positions that increased external rotation of the joint (pivoting) provided an improved seal, while positions that increased flexion combined with internal rotation (stooping) augmented the ease of fluid transport from the central to the peripheral compartment. Maximum pressure resistance was associated with the distance between the labrum and femoral head during pivoting. CONCLUSION: This study demonstrated that the transfer of fluid from the central compartment of the hip occurs at the junction of the labrum and femoral head. Joint position was shown to strongly affect the sealing function of the labrum and was attributable to the distance between the labrum and femoral head in certain positions. CLINICAL RELEVANCE: Altering the relationship between the labrum and femoral head may disrupt the sealing ability of the labrum, potentially leaving the joint at risk for pathological changes with time.

Comparison of gluteus medius muscle activity during functional tasks in individuals with and without osteoarthritis of the hip joint.

BACKGROUND: Neuromuscular alterations have been reported for patients with osteoarthritis of the hip joint; however, the underlying cause associated with altered gluteus medius muscle function has not been examined. This study assessed electromyographic amplitudes of the gluteus medius muscles during function in patients with unilateral end-stage osteoarthritis of the hip joint compared to controls. METHODS: Patients with unilateral end-stage hip joint osteoarthritis (n=13) and asymptomatic control participants (n=17) participated. Average root-mean squared muscle amplitudes represented as a percent of maximum voluntary isometric contraction for both the involved and uninvolved limb gluteus medius muscles were analyzed during step up, step down, and gait. The association between muscle activation and impact forces during stepping tasks was assessed. FINDINGS: Patients with hip osteoarthritis exhibited increased gluteus medius muscle electromyographic amplitudes bilaterally during stair ascent, stair descent, and gait compared to controls, regardless of which limb they led. Involved limb muscle activity was inversely related to impact force during step down onto the ipsilateral limb. INTERPRETATION: Patients with hip osteoarthritis demonstrated increased gluteus medius muscle activation levels during stepping tasks and gait when compared to controls. The increased activation is most likely a compensatory response to muscle weakness. Therefore, application of strengthening exercises which target the gluteal muscles should assist in neuromuscular control and result in improved strength for patients with hip joint osteoarthritis.

Comparison of lower extremity kinematics and hip muscle activation during rehabilitation tasks between sexes.

CONTEXT: Closed kinetic chain exercises are an integral part of rehabilitation programs after lower extremity injury. Sex differences in lower extremity kinematics have been reported during landing and cutting; however, less is known about sex differences in movement patterns and activation of the hip musculature during common lower extremity rehabilitation exercises. OBJECTIVE: To determine whether lower extremity kinematics and muscle activation levels differ between sexes during closed kinetic chain rehabilitation exercises. DESIGN: Cross-sectional with 1 between-subjects factor (sex) and 1 within-subjects factor (exercise). SETTING: Research laboratory. PATIENTS OR OTHER PARTICIPANTS: Participants included 21 women (age = 23 +/- 5.8 years, height = 167.6 +/- 5.1 cm, mass = 63.7 +/- 5.9 kg) and 21 men (age = 23 +/- 4.0 years, height = 181.4 +/- 7.4 cm, mass = 85.6 +/- 16.5 kg). INTERVENTION(S): In 1 testing session, participants performed 3 trials each of single-leg squat, lunge, and step-up-and-over exercises. MAIN OUTCOME MEASURE(S): We recorded the peak joint angles (degrees) of knee flexion and valgus and hip flexion, extension, adduction, and external rotation for each exercise. We also recorded the electromyographic activity of the gluteus maximus, rectus femoris, adductor longus, and bilateral gluteus medius muscles for the concentric and eccentric phases of each exercise. RESULTS: Peak knee flexion angles were smaller and peak hip extension angles were larger for women than for men across all tasks. Peak hip flexion angles during the single-leg squat were smaller for women than for men. Mean root-mean-square amplitudes for the gluteus maximus and rectus femoris muscles in both the concentric and eccentric phases of the 3 exercises were greater for women than for men. CONCLUSIONS: Sex differences were observed in sagittal-plane movement patterns during the rehabilitation exercises. Because of the sex differences observed in our study, future researchers need to compare the findings for injured participants by sex to garner a better representation of altered kinematic angles and muscle activation levels due to injury.