Correlation of Single Assessment Numerical Evaluation Score for Sport and Activities of Daily Living to Modified Harris Hip Score and Hip Outcome Score in Patients Undergoing Arthroscopic Hip Surgery

Association Between Symptoms of Anxiety and Depression, Hip Pathology, and Patient-Reported Outcomes After Hip Arthroscopy for Femoroacetabular Impingement

BACKGROUND

In patients with femoroacetabular impingement (FAI), mental health has been implicated in both symptom severity and postoperative outcomes. However, there are limited data regarding the independent influences of baseline mental health and hip pathology on patient-reported outcomes over time after hip arthroscopy.

PURPOSE

To evaluate the association between mental health and structural hip pathology with pain, hip function, and quality of life (QOL).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patient records from a single surgeon's hip outcomes registry were retrospectively reviewed. Mental health was evaluated using the Patient-Reported Outcomes Measurement Information System Anxiety and Depression scores. Pain was evaluated with the Single Assessment Numeric Evaluation score for Activities of Daily Living (SANE-ADL), while hip-related QOL was evaluated with the 12-item International Hip Outcome Tool (iHOT-12). Hip function was assessed with the Hip Outcome Score (HOS) Sport-Specific (SS) and ADL subscales. Separate mixed models were used to predict pain, QOL, and hip function, including hip pathology measures (size of labral tear, grade of chondral damage, preoperative alpha angle), anxiety, depression, and time as fixed effects and individuals as a random effect.

RESULTS

A total of 312 patients were included in this study. The preoperative alpha angle, degree of intraoperative cartilage damage, and size of the labral tear were not associated with pain or QOL (P > .05 for all). However, higher levels of anxiety and depression were significantly associated with lower SANE-ADL scores (estimate ± SE) (anxiety: -0.59 ± 0.07, P < .0001; depression: -0.64 ± 0.08, P < .0001), iHOT-12 scores (anxiety: -0.72 ± 0.07, P < .0001; depression: -0.72 ± 0.08, P < .0001), HOS-SS scores (anxiety: -0.68 ± 0.09, P < .0001; depression: -0.57 ± 0.10, P < .0001), and HOS-ADL scores (anxiety: -0.43 ± 0.05, P < .0001; depression: -0.43 ± 0.06, P < .0001).

CONCLUSION

Patients had similar improvements in pain scores, QOL, and hip function after hip arthroscopy for FAI irrespective of their degree of hip pathology. Additionally, preoperative symptoms of anxiety and depression symptoms were associated with greater pain, decreased QOL, and worse hip function both pre- and postoperatively, independent of the degree of hip pathology. This suggests that efforts to directly address symptoms of anxiety and depression may improve outcomes after hip arthroscopy.

Serum glutathione peroxidase 4 as a novel biomarker for nontraumatic osteonecrosis of the femoral head: A retrospective case-control study

There are no serum biomarkers available in nontraumatic osteonecrosis of the femoral head in clinical practice. This study aimed to evaluate the clinical value of serum glutathione peroxidase 4 in nontraumatic osteonecrosis of the femoral head. This retrospective study analyzed serum glutathione peroxidase 4 levels and clinical data of 80 patients with nontraumatic osteonecrosis of the femoral head and 80 healthy controls between August 2021 and May 2022. Serum glutathione peroxidase 4 levels were analyzed using an enzyme-linked immunosorbent assay. The Association Research Circulation Osseous classification system determined disease progression. Clinical severity was assessed by Harris hip score and visual analogue scale. Correlations between serum glutathione peroxidase 4 and disease progression as well as clinical severity were evaluated statistically. The diagnostic accuracy of serum glutathione peroxidase 4 in nontraumatic osteonecrosis of the femoral head was determined using receiver operating characteristic analysis. The baseline characteristics of participants between 2 groups were comparable. Patients with nontraumatic osteonecrosis of the femoral head displayed a decreased glutathione peroxidase 4 level compared with healthy controls (11.87 ± 2.76 μU/mL vs 16.54 ± 4.89 μU/mL, P < .01). The levels of glutathione peroxidase 4 were inversely correlated with Association Research Circulation Osseous stage (P < .01) and visual analogue scale scores (P < .01), and positively correlated with Harris score (P < .01). Receiver operating characteristic analyses showed that area under curves of glutathione peroxidase 4 was 0.808 (95% CI 0.721-0.858) and 0.847 (95% CI 0.743-0.951) with regard to diagnosis and collapse prediction in nontraumatic osteonecrosis of the femoral head, respectively. Serum glutathione peroxidase 4 could serve as a novel biomarker for diagnosing nontraumatic osteonecrosis of the femoral head and predicting collapse of the femoral head.

Patient Outcomes Are Not Improved by Platelet-Rich Plasma Injection Onto the Capsule at the Time of Closure During Hip Arthroscopy for Femoroacetabular Impingement Syndrome

Purpose

To determine the effect of platelet-rich plasma (PRP) injection onto the capsule at time of closure on outcomes of patients undergoing hip arthroscopy for femoroacetabular impingement syndrome.

Methods

Patients who underwent hip arthroscopy between January 2014 and December 2021 were retrospectively identified. The first cohort included patients who received PRP injection onto the capsule following capsular closure at the conclusion of the case. The second cohort did not receive PRP. Pain scores on a visual analog scale, Modified Harris Hip Scores, Single Assessment Numeric Evaluation (SANE), as well as Patient-Reported Outcomes Measurement Information System Physical Function scores were obtained preoperatively as well as at multiple time points postoperatively up to 2 years.

Results

In total, 345 patients were included in the study, with 293 in the PRP cohort and 52 in the non-PRP cohort. There was no significance difference in age (P = .69), sex, or preoperative pain (P = .92) and patient-reported outcome scores between the 2 groups (modified Harris Hip Score, P = .38; Patient-Reported Outcomes Measurement Information System Physical Function, P = .48), except for preoperative SANE scores, which had a greater baseline in the PRP group (P < .001). Using both observed data as well as repeated measure analysis of variance model to estimate for missing data after baseline, we found there were no differences in visual analog scale pain scores nor patient-reported outcome scores at any time point. There was similarly no difference in change from baseline for SANE scores. There was no difference in rate of revision surgery between the 2 cohorts (P = .66).

Conclusions

Based on the results of this study, intraoperative PRP injection onto the capsule at the time of capsular closure does not improve outcomes of patients undergoing hip arthroscopy for femoroacetabular impingement syndrome.

Level of Evidence

Level III, retrospective comparative study.

Benefits of a Postoperative Hip Orthosis After Routine Arthroscopy of the Hip: A Retrospective Cohort Study

Background

No consensus currently exists among orthopaedic surgeons regarding the benefits of hip orthosis after routine hip arthroscopy.

Purpose

To compare patient-reported outcome measures (PROMs) and reoperation rates between patients who were braced versus those who were not braced after routine hip arthroscopy.

Study Design

Cohort study; Level of evidence, 3.

Methods

A retrospective review was conducted of 193 patients who underwent hip arthroscopy for femoroacetabular impingement (FAI) from January 1, 2018, to December 31, 2021, by 2 orthopedic surgeons at a single institution. Patients before July 1, 2019, were immobilized in a hip orthosis after hip arthroscopy (braced group; n = 101), whereas those after July 1, 2019, were not (nonbraced group; n = 92). Baseline PROMs (visual analog scale for pain, modified Harris Hip Score, Single Assessment Numeric Evaluation, and Veterans Rand 12-Item Health Survey [VR-12] Physical Component Summary and Mental Component Summary) were obtained for all patients and were repeated postoperatively at 2 weeks, 4 weeks, 3 months, 6 months, 1 year, and 2 years. The study groups were compared to evaluate differences in PROMs over time and 2-year postoperative reoperation rates. Group comparisons were also stratified by patient sex.

Results

There were no significant differences on any PROM between the braced and nonbraced cohorts at any timepoint. There were also no significant group differences in reoperation rates, with 8 braced patients (7.9%) undergoing reoperation and 1 nonbraced patient (2.3%) undergoing reoperation (P = .208). In the sex-stratified analyses, nonbraced male patients had significantly higher VAS pain and lower VR-12 Mental Component Summary scores at 6 months postoperatively compared with braced male patients (P = .043 and .026, respectively).

Conclusion

The study findings suggested that the use of an orthosis after routine hip arthroscopy for FAI does not improve patient-reported outcomes or negatively affect the 2-year reoperation rate. Postoperative bracing increases perioperative cost, and by foregoing routine bracing, patients may avoid the morbidity associated with wearing a brace for a prolonged period.

Effect of Psychosocial Interventions for Individuals Who Underwent Arthroscopy in Femoroacetabular Impingement: A Randomized Controlled Trial

PURPOSE

The purpose of this protocol was to discover the connection between patients with non-surgical pain or other discomfort and their psychosocial status. Cognitive behavior therapy will be used, which we verified will determine the effect and feasibility of postoperative rehabilitation processes.

MATERIALS AND METHODS

This study will include 200 patients ranging from 18 to 60 years old who have underwent or will undergo FAI arthroscopy in the West China Hospital Sports Medicine Center from 2023 to 2026. A standardized prospective single-center parallel-group randomized controlled trial will be used for these participants. The participants will be divided into intervention (telephone versus face-to-face versus music versus floatation) and control groups. The follow-up periods will be measured pre-operatively, as well as postoperatively at 1, 3, and 6 months. The primary outcomes will include the modified Harris Hip Score (mHHS) and the Visual Analogic Score (VAS), and the secondary outcomes will include the range of motion (ROM), the Huaxi Emotional-distress Index (HEI), and the depression, anxiety, and stress scale (DASS-21 scale). Furthermore, the Patient Health Questionnaire-9 (PHQ-9) and a Short-Form 12 (SF-12) questionnaire will also be evaluated.

DISCUSSION

This study will evaluate the clinical and cost-effectiveness of different types of psychosocial-therapy-based rehabilitation methods designed to improve the quality of life of FAI patients with persistent symptoms.

Gadolinium injected concurrently with anesthetic can result in false-negative diagnostic intra-articular hip injections

PURPOSE

The purpose of this paper was to evaluate the response to intra-articular hip injections with and without concurrent gadolinium administration. Our secondary outcome was to compare post-operative outcomes between patients with an initial false-negative gadolinium-containing injection and a matched control group.

METHODS

Patients receiving a series of two hip diagnostic intra-articular injections (DIAI), the first with gadolinium for concurrent MRA and the second without gadolinium, were retrospectively identified. Pain response to DIAI, injectate volume, local anesthetic volume, inclusion of corticosteroids, and method of injection were compared between injections. False-negative injection was defined as < 50% pain relief with concurrent gadolinium, but ≥ 50% pain relief with subsequent anesthetic injection without gadolinium. False-negative injections in patients that ultimately underwent primary hip arthroscopy were identified from this cohort and matched in a 3:1 ratio to a control cohort to compare short-term post-operative single assessment numerical evaluation (SANE) outcomes.

RESULTS

Forty-three patients underwent a series of anesthetic injections with and without gadolinium and met inclusion and exclusion criteria. Pain response was significantly different in injections performed with and without gadolinium (18% vs. 81%; p < 0.001). There were significant differences in total injectate volume, local anesthetic volume, corticosteroid use, and method of injection between injections, but these variables were not correlated with pain response. Fifteen patients with false-negative responses to injection underwent primary hip arthroscopy and were matched in a 3:1 ratio to a control cohort. There was no difference in short-term post-operative SANE scores between the gadolinium-sensitive and control groups (81.6 vs. 80.0, n.s.).

CONCLUSION

Concurrent administration of intra-articular gadolinium with DIAI may result in a false-negative response to anesthetic. Additionally, in patients with initial false-negative DIAI with gadolinium, short-term post-operative outcomes after hip arthroscopy are similar to a matched cohort.

LEVEL OF EVIDENCE

Level III.

Serum nicotinamide phosphoribosyltransferase as a novel biomarker for non-traumatic osteonecrosis of the femoral head

OBJECTIVE

The aim of this study was to investigate the potential role of serum nicotinamide phosphoribosyltransferase (NAMPT) in non-traumatic osteonecrosis of femoral head (NONFH).

METHODS

A total of 113 NONFH patients and 81 healthy individuals were included in this study. The NAMPT levels in serum were measured by a commercial enzyme-linked immunosorbent assay kit. Radiographic progression was determined using Association Research Circulation Osseous (ARCO) classification system. Clinical severity was assessed by Harris hip score (HHS) and visual analogue scale (VAS). Correlations between serum NAMPT and radiographic progression as well as clinical severity were evaluated statistically. Receiver operating characteristic (ROC) curves were performed to evaluate the diagnostic values of NAMPT in NONFH potential and disease severity.

RESULTS

The serum NAMPT levels in NONFH patients were significantly lower than that in healthy controls. There were no significant differences among alcohol-induced group, steroids-induced group, and idiopathic group. NONFH patients with ARCO stage 4 had significant lower serum NAMPT levels in comparisons with ARCO stage 3 and 2, respectively. Lower serum NAMPT levels were also observed in bilateral NONFH cases compared with cases with unilateral NONFH. In addition, serum NAMPT was negatively correlated with ARCO stages and VAS scores, and positively correlated with HHS. ROC curve analysis indicated that serum NAMPT may serve as a novel biomarker for diagnosing early NONFH and for monitoring disease severity.

CONCLUSIONS

Our results suggest that serum NAMPT may serve as a novel biomarker for NONFH potential and disease severity.

Recommendations in the rehabilitation of patients undergoing hip abductor tendon repair: a systematic literature search and evidence based rehabilitation protocol

INTRODUCTION

Advanced hip imaging and surgical findings have demonstrated that a common cause of greater trochanteric pain syndrome (GTPS) is hip abductor tendon (HAT) tears. Traditionally, these patients have been managed non-operatively, often with temporary pain relief. More recently, there has been an increase in published work presenting the results of surgical intervention. A variety of open and endoscopic transtendinous, transosseous and/or bone anchored suture surgical techniques have been reported, with and without the use of tendon augmentation for repair reinforcement. While patient outcomes have demonstrated improvements in pain, symptoms and function, post-operative rehabilitation guidelines are often vague and underreported, providing no guidance to therapists.

MATERIALS AND METHODS

A systematic search of the literature was initially undertaken to identify published clinical studies on patients undergoing HAT repair, over a 3-year period up until May 2020. Following the application of strict inclusion and exclusion criteria, studies were identified and the detail relevant to rehabilitation was synthesized and presented. Published detail was combined with the authors clinical experience, with a detailed overview of rehabilitation proposed for this patient cohort.

RESULTS

A total of 17 studies were included, reporting varied detail on components of rehabilitation including post-operative weight bearing (WB) restrictions, the initiation of passive/active hip range of motion (ROM) and resistance exercises. A detailed rehabilitation guide is proposed.

CONCLUSION

In combining the current published literature on rehabilitation after HAT repair and our own clinical experience in the surgical management and post-operative rehabilitation of these patients, we present an evidence-based, structured rehabilitation protocol to better assist surgeons and therapists in treating these patients. This rehabilitation protocol has been implemented for several years through our institutions with encouraging published clinical outcomes.

Puntajes IV

El Comité Editorial quiere brindar a los lectores de la RAAOT una actualización de las escalas de uso corriente. El empleo de tablas y escalas es una práctica muy extendida en la ortopedia y traumatología. La medición y la cuantificación de los aspectos clínicos, funcionales y radiográficos se convirtieron en una herramienta imprescindible para la toma de decisiones en diferentes aspectos de la actividad asistencial. Llevamos a cabo una revisión de las escalas más utilizadas, definimos su uso e incluimos bibliografía original y actualizada.

Satisfactory results after endoscopic gluteus medius repair combined with selective gluteus maximus reflected tendon release for the treatment of a full-thickness tear of gluteus medius

PURPOSE

The current study aimed to report the mid-term follow-up results of endoscopic gluteus medius repair combined with a systematic release of the gluteus maximus reflected tendon.

METHODS

Twenty-two patients with a symptomatic full-thickness tear of the gluteus medius tendon, as diagnosed by clinical examination and imaging (MRI), and who had a failure of conservative treatment for at least 6 months, were retrospectively enrolled for this study. An endoscopic repair of gluteus medius was performed for all patients in combination with gluteus maximus reflected tendon release according to the Polesello technique. The Visual Analogue Scale (VAS) for pain, Modified Harris Hip Score (mHHS), Lower Extremity Functional Scale (LEFS), Hip Outcome Score-Activity Daily Life (HOS-ADL), and Hip Outcome Score-Sport Specific Subscale (HOS-SSS) were administered to each patient before surgery for 6 months, 1 year, and every following year after surgery.

RESULTS

All analysed hip scores (mHHS, LEFS, HOS-ADL, and HOS-SSS) showed statistically significant improvements between the pre-operative and post-operative values at 6 months, 1 year, and the latest follow-up appointments after surgery (p < 0.001). The mean pre-operative pain was 8.6 ± 1.0 on the VAS. After surgical treatment, the pain was significantly reduced (p < 0.001) on the VAS at 6 months (5.4 ± 1.5), 1 year (4.4 ± 1.8) and the latest follow-up control visit (3.6 ± 2.2). No patient-reported major complications (re-rupture, deep infection or neurovascular injury). Eleven (50%) patients indicated the results as excellent, 7 (32%) as good, 2 (9%) as fair, and 2 (9%) as poor.

CONCLUSION

The use of abductor tendon repair in combination with a systematic release of the reflected tendon of the gluteus maximus according to the Polesello technique seems to be a safe and effective endoscopic way of treating a full-thickness tear of the gluteus medius.

LEVEL OF EVIDENCE

Level IV.

Intraoperative Findings and Clinical Outcomes Associated With Arthroscopic Management of Subspine Impingement: A Propensity-Matched, Controlled Study

PURPOSE

(1) To investigate intra-articular damage in the hip joint associated with subspine impingement (SSI); (2) to evaluate clinical outcomes of arthroscopic treatment of hips with SSI; and (3) to compare the findings and outcomes to a control group without SSI.

METHODS

Eligible patients had arthroscopic treatment for femoroacetabular impingement (FAI) concurrent with SSI between January 2015 and December 2017. Inclusion criteria consisted of preoperative and minimum 2-year patient-reported outcomes and preoperative measurements for Tönnis, lateral center edge angle, and alpha angle. Included patients were propensity-matched in a 1:3 ratio to patients who had FAI without SSI. Patient-reported outcomes were compared between groups. Minimal clinically important difference was calculated for modified Harris Hip Score (mHHS) and Hip Outcome Score-Sports Specific Subscale (HOS-SSS).

RESULTS

Fifty SSI cases were matched to 150 patients who had FAI without SSI. A greater proportion of the SSI cohort required labral reconstruction (P = .010). The size and locations for labral tears and chondral defects were comparable between groups (P > .05). Both groups demonstrated similar minimum 2-year outcomes for mHHS (P = .103), Nonarthritic Hip Score (P = .200), HOS-SSS (P = .119), visual analog scale (P = .231), international Hip Outcome Tool-12 (P =.300), Short Form-12 Mental (P = .426), Short Form-12 Physical (P = .328), Veterans RAND 12-Item Health Survey, Mental (P = .419), and Veterans RAND 12-Item Health Survey, Physical (P = .316). The percentage of patients achieving minimal clinically important difference for mHHS and HOS-SSS was similar (P > .05). Survivorship was 96.0% and 98.7% for the SSI and control cohorts at 2 years, respectively.

CONCLUSIONS

Arthroscopic treatment of hips with SSI with subspine decompression and concomitant treatment of labral tears and FAI yielded significant improvement in patients' outcomes, which compared favorably with the control group. SSI may correlate with more complex labral tears, not amenable to repair, and complete tears of the ligamentum teres. Other findings, such as location and size of intra-articular damage, were similar between the cohorts.

LEVEL OF EVIDENCE

III, case-control study.

Improvements in lower-extremity patient-reported outcomes after lumbar interbody fusion

OBJECTIVE

Recently, new patient-reported outcome measures (PROMs) of the spine were designed to overcome the limitations of previous spinal PROMs and to consider the whole spine as a single kinetic functional unit. Owing to the significance of spine-hip-knee and global body balance, the spine and lower extremities cannot be considered separately. However, no reports have evaluated lower-extremity functional outcome using PROMs after lumbar spine surgery. The authors aimed to elucidate changes in hip and knee PROMs after lumbar interbody fusion and to evaluate the sagittal spinopelvic radiographic parameters that were most strongly correlated with lower-extremity PROMs.

METHODS

In 2018, the authors consecutively evaluated patients who underwent lumbar interbody fusion surgery with at most three levels. Preoperative and 1-year postoperative clinical and radiographic data were assessed. Spinal functional outcomes were measured with the Oswestry Disability Index (ODI), visual analog scale (VAS) for pain, and Scoliosis Research Society-22r (SRS-22r) questionnaire. Lower-extremity functional outcomes were evaluated with the Harris Hip Score (HHS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Linear regression was used to evaluate the relationship between spinal and lower-extremity PROMs and spinopelvic radiographic parameters.

RESULTS

The authors enrolled 67 patients, with a mean age of 66.4 years. The average number of surgical levels was 1.7. All assessed PROMs improved significantly after surgery (p < 0.001 for ODI, p < 0.001 for VAS, p = 0.017 for SRS-22r, p = 0.042 for HHS, and p = 0.033 for WOMAC). Spinopelvic parameters, including lumbar lordosis (LL), pelvic tilt (PT), C7 sagittal vertical axis, and sagittal radiographic parameters of hip and knee, significantly improved after surgery. On linear regression analysis, HHS and WOMAC correlated with LL and PT, respectively (β = 0.554 and p = 0.043 for correlation of HHS with LL; β = 1.573 and p = 0.021 for correlation of WOMAC with PT).

CONCLUSIONS

The current study demonstrated that lumbar fusion surgery may induce postoperative improvements in lower-extremity functional and radiological outcomes. However, among radiographic parameters, changes in LL and PT were the most strongly associated with lower-extremity PROMs.

Correlation of the Single-Assessment Numeric Evaluation (SANE) Score With Hip-Specific Patient-Reported Outcome Measures

Purpose

The purpose of this study was to determine if the Single-Assessment Numeric Evaluation (SANE) score correlates with existing validated hip-specific patient-reported outcome measures (PROMs), including the Modified Harris Hip Score (mHHS), the International Hip Outcome Tool (IHOT-33), the Hip Outcome Score, Activities of Daily Living subscale (HOS-ADL), and the Hip Outcome Score, Sport-Specific subscale (HOS-SS), for patients preparing to undergo hip arthroscopy for treatment of femoroacetabular impingement syndrome (FAIS).

Methods

A single surgeon's operative database was retrospectively reviewed to identify patients undergoing primary hip arthroscopy for treatment of FAIS from April 2018 to October 2019. Patient-specific factors including age, sex, body mass index (BMI), and duration of symptoms were collected. Preoperative SANE, mHHS, IHOT-33, HOS-ADL, and HOS-SS scores were analyzed. Statistical analysis using Pearson correlation was performed to identify the relationship between the SANE score and the mHHS, IHOT-33, HOS-ADL, and HOS-SS, preoperatively.

Results

154 patients were included in the study. The mean mHHS was 54.4 ± 11.7; mean IHOT-33 score was 32.7 ± 15.0; mean HOS-SS 42.9 ± 23.7; and mean HOS-ADL was 63.3 ± 1. The mean SANE score was 36.7 ± 19.9. The Simple Hip Score was directly correlated with the mHHS (P < .01), the IHOT-33 (P < .01); the HOS-ADL (P < .01), and the HOS-SS (P < .01). The mean patient age was 35.9 years; 109 (70.8%) were female and 45 (29.2%) were male. Average patient BMI was 26.9. At the time of patient completion of the questionnaire, the majority of patients (65%) had been having symptoms for >1 year.

Conclusion

The SANE score was strongly correlated with mHHS, IHOT-33, HOS-ADL, and HOS-SS in the preoperative setting for patients undergoing hip arthroscopy for treatment of FAIS. Given its simplicity, SANE may be a valuable tool for rapid assessment of joint function and pain in this patient population.

Level of Evidence

IV, therapeutic case series.

Factors affecting dislocation after bipolar hemiarthroplasty in patients with femoral neck fracture

PURPOSE

This study aimed to investigate the anatomic risk factors associated with dislocation following bipolar hemiarthroplasty for the treatment of femoral neck fracture.

MATERIALS AND METHODS

We retrospectively reviewed 208 consecutive patients (133 women, 75 men) with femoral neck fractures who were treated with bipolar hemiarthroplasty between 2015 and 2018. A comparative analysis was performed between dislocation (n = 18) and non-dislocation (n = 190) groups in terms of patient demographics, surgical and pelvic morphologic factors, and clinical outcomes, including postoperative Harris and modified Harris hip scores. Independent risk factors affecting dislocation were also evaluated.

RESULTS

The mean follow-up period was 30.8 ± 2.0 (range, 12-48) months. The mean age was 79.2 ± 7.4 (range, 71-94) years. The dislocation rate was 8.6% (18/208), and the mean dislocation time after operation was 2.0 ± 1.1 (range, 1-4) months. Patient-related factors did not differ between the dislocated and non-dislocated groups. As regards dislocation, statistically significant difference was observed in surgical and pelvic morphologic factors, including femoral offset, residual femoral neck length, trochanter upper end and femoral head center distance, and height of the hip center of the operated side (p = 0.025, p = 0.013, p = 0.002, p = 0.008, respectively). Moreover, the femoral offset, height of the hip center, and femoral neck-shaft angle of the non-operated side are significantly different between the groups (p = 0.007, p = 0.001, p = 0.027, respectively). Decrease in the center edge (CE) angle, offset of prosthesis, and increase in femoral head extrusion index (FHEI) of the operated side and decrease in the height of the hip center of the non-operated side increased the risk of dislocation (p = 0.030, OR: 1,306; p = 0.041, OR: 8.15; p = 0.020, OR: 1.038; p = 0.010, OR: 2.02, respectively).

CONCLUSIONS

Pelvic morphologic features and surgical factors were found to affect dislocation. Patients with smaller OP, CE angle of the operated side, and higher FHEI and smaller height of the hip center of the non-operated side should be carefully monitored to decrease postoperative dislocation.