Maureen K. Dwyer

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

BackgroundSome 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.

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.

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.

Commonalities, differences, and challenges with patient-derived outcome measurement tools: function/activity scales.

BackgroundThere is a critical need to evaluate the success of orthopaedic treatments through valid outcome measures. Previous attempts to express patient outcomes using a single aggregate score led to scores that were ambiguous, often insensitive to change, and poorly correlated with the patient’s assessment of the outcome of surgical procedures.Where Are We Now?Numerous patient-reported outcome measurement tools have been developed for assessment of patients’ level of activity and functional status, especially after joint arthroplasty. However, most tools assume an idealized set of prescribed activities independent of the age, activity level, and lifestyle of each individual. Few instruments are designed to capture the priorities of individual patients, especially those involved in high-demand sporting and recreational activities.Where Do We Need to Go?We need valid outcome measures that provide a meaningful, individualized assessment of the functional status of each patient, taking into account the lifestyle and expectation of each individual. This advance in outcome measurement will allow clinicians to individualize treatment and provide patients with an accurate estimate of the outcome of alternative treatments and procedures.How Do We Get There?Much more comprehensive information is needed to characterize the activities, abilities, and physical aspirations of individual patients. This could form a database for the development of predictive models relating individual characteristics to functional outcomes. Statistical tools are needed to minimize the burden on patients in completing questionnaires to access predictive data and to ensure that all outcome assessments are psychometrically valid.

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.

Functional Mechanics of the Human Hip

The application of scientific principles to the study of the hip has provided insight into morphologic and biomechanical factors compromising hip function, including acquired abnormalities (e.g., posttraumatic deformities, Perthes disease, slipped capital femoral epiphysis), developmental pathologies (e.g., developmental dysplasia of the hip [DDH]), and abnormalities of unknown origin (e.g., cam deformity of the femoral head-neck junction and pincer deformities of the acetabular margin).

Activities, Symptoms, and Expectations of Patients Undergoing Hip Surgery

Does hip surgery restore normal hip function? While it is generally accepted that surgery is performed to avoid, or overcome, pain and deterioration of function, the underlying pathologies of hip deformity and dysfunction differ. Three common surgical procedures—hip osteotomy, hip arthroscopy, and total hip replacement—treat hip pathologies at three very different stages of life.

Evaluating the Outcome of Hip Preserving Procedures: Patient Function, Satisfaction, and Impairment

As hip arthroscopy advances, it becomes increasingly important to evaluate outcomes in terms of long-term patient function and satisfaction. Given the broad spectrum of patients seeking arthroscopic procedures, it is imperative that treatment plans and outcome instruments incorporate the goals of both traditional and younger, more active patients. This is only possible, if we have a valid understanding of the factors that contribute to good or poor outcomes following hip surgery.

FAI Negates the Acetabular Labral Seal during Pivoting Maneuvers, but not Normal Gait

Objectives: 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 femoro-acetabular impingement (FAI) have a similar impact on labral function. This study was performed to determine the effect of natural labral damage secondary to abnormal femoral morphology on the labral seal. Methods: Ten intact hip specimens were obtained from male donors (47.8 ± 1.5 yrs) for use in this study. CT reconstructions demonstrated that 6 specimens were of normal morphology, while 4 displayed morphology typical of cam-FAI. Specimens were dissected free of the overlying soft tissue, leaving the capsule and labrum intact. Each specimen was potted and placed in a loading apparatus (0.5 BW). Pressures developed within the central and peripheral compartments were monitored with miniature pressure transducers. The sealing capacity of the labrum was measured by introducing fluid into the central compartment at a constant rate until transport was detected from the central to the peripheral compartment. These measurements were performed in 10 functional positions simulating sequential stages of gait, stooping, and pivoting. During testing, the 3D motion of the femoral head in the acetabulum was measured with motion analysis combined with computer visualization. Peak pressures were compared between specimens with and without labral damage for each of the three activities (p Results: Visual observation following testing showed that each specimen with CAM morphology exhibited secondary damage of the labrum and the adjacent chondral surface, while specimens of normal morphology were undamaged. Average peak central compartment pressure was affected by the presence of labral damage secondary to impingement. The specimens with labral damage exhibited reduced peak central compartment pressure during pivot (15.2 ± 2.6 vs. 42.3 ± 7.7 kPa; p = 0.007) when compared to intact specimens. Conversely, no differences in peak pressure were detected between specimens with and without labral damage during simulated gait (21.1 ± 6.0 vs. 22.0 ± 4.2 kPA; p = 0.9) and stooping (8.6 ± 2.4 vs. 7.5 ± 2.6 kPa; p = 0.78). Conclusions: The acetabular seal, quantified by intra-articular pressure, was affected by the presence of labral damage secondary to impingement. The reduction in ultimate pressure occurred during pivoting; however, the seal was maintained during gait and stooping. These results are in contrast to previous studies which reported a complete negation of the seal in response to experimentally-created labral disruption. As degeneration is progressive with repetitive impingement, loss of the seal starts to be seen during pivoting and may progress from there, but at this time point (50 years), the seal remains intact during gait and stooping. Our study highlights the importance of using clinically relevant joint injury models to study labral function.