Outcomes of Tibiotalocalcaneal Arthrodesis vs Talar Body Prosthesis as Treatment of Collapsed Avascular Necrosis of the Talus: A 10- to 13-Year-Follow-up Retrospective Comparative Study.

BACKGROUND: Joint salvage surgeries such as tibiotalocalcaneal arthrodesis and talar prosthesis are commonly used in the surgical treatment of collapsed avascular necrosis of the talus (AVNT). However, differences in outcomes of these 2 surgical treatments are still inconclusive. This study compared the 10- to 13-year outcomes and 10-year survivorship rates of tibiotalocalcaneal arthrodesis and talar body prosthesis in the surgical treatment of collapsed AVNT. METHODS: A retrospective comparative study was conducted of patients who underwent either tibiotalocalcaneal arthrodesis or talar body prosthesis implantation between 2005 and 2012. The demographic matching process resulted in 24 patients per treatment group. Clinical outcomes were evaluated using a numeric rating scale (NRS) of 2 hours of activities of daily living (ADL) and Foot and Ankle Ability Measure (FAAM) for ADL. Radiographic assessments included the incidence of nonunion, adjacent joint arthritis, and prosthesis loosening. The 10-year survivorship of both surgical treatments was calculated. A P value of less than .05 was considered statistically significant. RESULTS: The median NRS of 2 hours of ADL and FAAM score for ADL were statistically significantly better in the talar body prosthesis group, with P values of .001 and <.001, respectively. The statistically significant differences in FAAM score for ADL exceeded the minimum clinically important difference. In the tibiotalocalcaneal arthrodesis group, nonunion was observed in 7 of 24 patients (29.2%). No prosthesis loosening was reported in the talar body prosthesis group. The 10-year survivorship was statistically significantly higher in talar body prosthesis than tibiotalocalcaneal arthrodesis (95.8% vs 70.8%), P = .023. CONCLUSION: Talar body prosthesis implantation in selected eligible patients demonstrated statistically significantly better 10- to 13-year clinical outcomes and higher 10-year survivorship compared with tibiotalocalcaneal arthrodesis in the surgical treatment of collapsed AVNT. LEVEL OF EVIDENCE: Level III, retrospective cohort comparative study.

What Are the MSTS Scores and Complications Associated With the Use of Three-dimensional Printed, Custom-made Prostheses in Patients Who Had Resection of Tumors of the Hand and Foot?

BACKGROUND: There are a few good options for restoring bone defects in the hand and foot. 3D-printed implants have been used in the pelvis and elsewhere, but to our knowledge, they have not been evaluated in the hand and foot. The functional outcome, complications, and longevity of 3D-printed prostheses in small bones are not well known. QUESTIONS/PURPOSES: (1) What are the functional outcomes of patients with hand or foot tumors who were treated with tumor resection and reconstruction with a 3D-printed custom prosthesis? (2) What complications are associated with using these prostheses? (3) What is the 5-year Kaplan-Meier cumulative incidence of implant breakage and reoperation? METHODS: Between January 2017 and October 2020, we treated 276 patients who had tumors of the hands or feet. Of those, we considered as potentially eligible patients who might have extensive loss in their joint that could not be fixed with a bone graft, cement, or any prostheses available on the market. Based on this, 93 patients were eligible; a further 77 were excluded because they received nonoperative treatment such as chemoradiation, resection without reconstruction, reconstruction using other materials, or ray amputation; another three were lost before the minimum study follow-up of 2 years and two had incomplete datasets, leaving 11 for analysis in this retrospective study. There were seven women and four men. The median age was 29 years (range 11 to 71 years). There were five hand tumors and six tumors of the feet. Tumor types were giant cell tumor of bone (five), chondroblastoma (two), osteosarcoma (two), neuroendocrine tumor (one), and squamous cell carcinoma (one). Margin status after resection was ≥ 1 mm. All patients were followed for a minimum of 24 months. The median follow-up time was 47 months (range 25 to 67 months). Clinical data; function according to the Musculoskeletal Tumor Society, DASH, and American Orthopedic Foot and Ankle Society scores; complications; and survivorship of implants were recorded during follow-up in the clinic, or patients with complete charts and recorded data were interviewed on the telephone by our research associates, orthopaedic oncology fellows, or the surgeons who performed the surgery. The cumulative incidence of implant breakage and reoperation was assessed using a Kaplan-Meier analysis. RESULTS: The median Musculoskeletal Tumor Society score was 28 of 30 (range 21 to 30). Seven of 11 patients experienced postoperative complications, primarily including hyperextension deformity and joint stiffness (three patients), joint subluxation (two), aseptic loosening (one), broken stem (one), and broken plate (one), but no infection or local recurrence occurred. Subluxations of the metacarpophalangeal and proximal interphalangeal joints in two patients' hands were caused by the design of the prosthesis without a joint or stem. These prostheses were revised to a second-generation prosthesis with joint and stem, leading to improved dexterity. The cumulative incidence of implant breakage and reoperation in the Kaplan-Meier analysis was 35% (95% CI 6% to 69%) and 29% (95% CI 3% to 66%) at 5 years, respectively. CONCLUSION: These preliminary findings suggest that 3D implants may be an option for reconstruction after resections that leave large bone and joint defects in the hand and foot. Although the functional results generally appeared to be good to excellent, complications and reoperations were frequent; thus, we believe this approach could be considered when patients have few or no alternatives other than amputation. Future studies will need to compare this approach to bone grafting or bone cementation. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Sport and Exercise Activity After Isolated Ankle Arthrodesis for Advanced-Stage Ankle Osteoarthritis: A Single-Center Retrospective Analysis.

Background: Ankle arthrodesis, a recognized operative treatment for advanced-stage ankle osteoarthritis (OA), is recommended when conservative treatment proves unsuccessful. This single-center retrospective analysis examined the change in functional outcomes and the type of sport/exercise activity performed by advanced-stage ankle OA patients after ankle arthrodesis treatment. Methods: A total of 61 advanced-stage ankle OA patients (age, 63.1 ± 12.6 years) who had undergone ankle arthrodesis were included in this single-center retrospective study. The patients had functional outcomes evaluated via American Orthopaedic Foot & Ankle Society Score (AOFAS), Foot Function Index (FFI), Tegner Activity Level Scale (TAS), and High-Activity Arthroplasty Score (HAAS) questionnaires. Clinical status was compared across prearthritic, arthritic, and postarthrodesis periods, and satisfaction with return to sport/exercise activity was recorded. Results: Patients' tarsal sagittal ROM (mean [95% CI]: 22.7 degrees [21.4-24.0]); time to union (15.7 weeks [11.8-19.6]); time to walk without gait aid (14.4 weeks [11.0-17.7]); time to return to work (17.9 weeks [15.1-20.8]); and time to exercise activity (20.6 weeks [17.9-23.4]) were recorded postarthrodesis. Hindfoot alignment angle toward a neutral position (difference: 11.4 degrees [9.2-13.6], P < .001) and functional outcomes (P < .001) significantly improved after arthrodesis surgery; however, only the TAS questionnaire indicated patients returned to their prearthritic activity level (P > .99). Patients generally reported "good" satisfaction with their recovery from ankle arthrodesis surgery, with 64% of patients returning to high-impact-type activity. Conclusion: Advanced-stage ankle OA patients had improved functional outcomes at ~1 year postarthrodesis surgery, enabling the majority of patients to return to high-impact-type activity. Level of Evidence: Level III, retrospective cohort study.

How Adductor Hallucis Reattachment Affects Outcomes Following Scarf Osteotomy in Hallux Valgus Correction: A 4- to 8-Year Follow-Up Retrospective Comparative Study.

This study observed the differences between 2 adductor hallucis release techniques (nonreattachment vs reattachment) in 4- to 8-year follow-up outcomes of scarf osteotomy combined with distal soft tissue release (DSTR) in moderate to severe hallux valgus correction. A retrospective review of moderate to severe hallux valgus patients treated with scarf osteotomy with DSTR was conducted. The patients were divided into 2 groups based on adductor hallucis release techniques (without and with reattachment to the metatarsophalangeal joint capsule). The demographic-matching process divided the samples into 27 patients per group. A comparison of last follow-up of clinical foot ankle ability measure (FAAM) for activity of daily living (ADL) and numerical rating scale for pain during 2 hours of ADL and radiographic outcomes (hallux valgus angle (HVA) and intermetatarsal angle (IMA) was analyzed. A p < .05 was considered a statistically significant difference. The final follow-up of FAAM for ADL was statistically better in the reattachment group as the median was 79.0 (IQR = 4.00) versus 76.0 (IQR = 4.00), p = .047. However, this difference did not achieve minimal clinical importance difference (MCID). The last follow-up of IMA was also statistically better in the reattachment group as the mean was 7.67 (SD = 3.10) versus 10.5 (SD = 3.59), p = .003. DSTR with adductor hallucis reattachment has statistically better IMA correction and maintenance than nonreattachment for moderate to severe hallux valgus correction using scarf osteotomy at 4- to 8-years follow-up. However, the better clinical outcomes did not achieve MCID.

The talar body prosthesis treated end-stage ankle arthritis with talar body deficient: a 6-13 years of follow-up outcomes and 6-year survivorship.

INTRODUCTION: Talar body deficient provides a unique challenge for ankle arthritis treatment. We studied the clinical-radiographic outcomes at 6 to 13 years and 6 year prosthesis survivorship of patients treated for ankle arthritis with poor talar body bone stock using a talar body prosthesis (TBP). MATERIALS AND METHODS: Between 2008 and 2015, we treated 32 consecutive end-stage ankle arthritis patients with talar body deficiency by TBP implantation and fascia interposition. One patient was excluded with a diagnosis of inflammatory arthritis. We assessed visual analogue scale (VAS) of ankle pain, sagittal range of motion, American Orthopaedics Foot and Ankle Society (AOFAS) ankle-hindfoot score, Foot Ankle Ability Measure (FAAM) of activity daily living (ADL), prosthesis tibiotalar surface angle, radiographic prosthesis loosening, adjacent joint arthritis and complication. Pre-operative to last follow-up outcomes (at 6-13 years) were compared. Prosthesis survivorship was analyzed at 6 year follow-up. p < 0.05 was considered a significant difference. RESULTS: There was statistically significant improvement of median VAS ankle pain, as 8.0 (IQR 1.0) to 1.0 (IQR 2.0), AOFAS ankle-hindfoot score from 48 (IQR 21) to 80 (IQR 7.0), FAAM of ADL from50.0 (28.0) to 88.0 (IQR 15.0), and sagittal ROM from 20o (IQR 19°) to 33° (IQR 14°), p < 0.05. The median tibiotalar surface angle was statistically significant improved from 85.0° (IQR 8.0°) to 89.0° (IQR 3.0°), p < 0.001. No radiographic prosthesis loosening or adjacent talonavicular-calcaneocuboid joint arthritis. The 6 year prosthesis survivorship was 93.5% (95% CI 84.9-100.0%). End of survivorship was observed in 2 patients due to progressive valgus tilting at 16° and 18°, respectively. No prosthesis was revised. CONCLUSIONS: TBP implantation with fascia replacing the articular end of distal tibia provided significant better pre- to post-operative clinical outcomes and had 6 year survivorship as 93.5% for the treatment of ankle arthritis with talar body deficient. LEVEL OF EVIDENCE: IV.

Evaluation of the implementation of multidisciplinary fast-track program for acute geriatric hip fractures at a University Hospital in resource-limited settings.

BACKGROUND: Hip fractures are common among frail, older people and associated with multiple adverse outcomes, including death. Timely and appropriate care by a multidisciplinary team may improve outcomes. Implementing a team to jointly deliver the service in resource-limited settings is challenging, particularly on the effectiveness of patient outcomes. METHODS: A retrospective cohort study to compare outcomes of hip fracture patients aged 65 or older admitted at Siriraj hospital before and after implementation of the Fast-track program for Acute Geriatric Hip Fractures. The primary outcome was the incidence of medical complications. The secondary outcomes were time to surgery, factors related to the occurrence of various complications, in-hospital mortality, and mortality at month 3, month 6 and month 12 after the operation. RESULTS: Three hundred two patients were enrolled from the Siriraj hospital's database from October 2016 to October 2018; 151 patients in each group with a mean age of 80 years were analyzed. Clinical parameters were similar between groups except the Fast-track group comprising more patients with dementia (37.1% VS 23.8%, p < 0.012). In the Fast-track group, there was a significantly higher proportion of patients underwent surgery within 72-h (80.3% VS 44.7%, p < 0.001) and the length of stay was significantly shorter (11 days (8-17) VS 13 days (9-18), p = 0.017). There was no significant difference in medical complications. Stratified analysis by dementia status showed a trend in delirium reduction in both patients with dementia and without dementia groups, and a pressure injury reduction among patients with dementia after the program was implemented but without statistical significance. There was no significant difference in mortality. CONCLUSIONS: The implementation of a multidisciplinary team for hip fracture patients is feasible in resource-limited setting. In the Fast-track program, time to surgery was reduced and the length of stay was shortened. Other outcome benefits were not shown, which may be due to incomplete uptake of all involved disciplines.

Minimal invasive surgery in the management of intra-articular calcaneal fractures: A retrospective comparison of screw fixation alone versus screw with small locking plate fixation techniques.

OBJECTIVE: The aim of this study was to compare clinical and radiological outcomes of screw fixation alone versus screw with small locking plate fixation techniques in the management of intra-articular calcaneal fractures by minimal invasive surgery. METHODS: A total of 42 patients treated with minimally invasive surgery because of an intra-articular calcaneal fracture were retrospectively reviewed and included in the study. The patient were then divided into two groups based on the implemented surgical technique: Group A, 20 patients (16 male, 4 female; mean age = 43.41 ± 15.50) receiving screw fixation alone and group B, 22 patients (17 male, 5 female; mean age = 43.38 ± 14.00) receiving screw with small locking plate fixation. The radiographic assessment included Bohler's, Gissane, joint line parallel, and calcaneal varus angles at immediate post-operative and 2-year follow up period through the calcaneal axial and lateral foot radiographs. RESULTS: There was a significant increase in joint line parallel angle from post-operative period to 2-year follow up in Group A compared to Group B, mean (SD) 3.27 (2.15) degrees versus (vs) 0.44 (3.00) degrees, P = 0.025. No statistical significant difference of the immediate, 2-year post-operative period and the change in Bohler's-Gissane angle, calcaneal varus, and FAAM of ADL between groups were observed, P > 0.05. For time-point comparisons in each group, there was a significant loss of calcaneal varus and increase in joint line parallel angle from post-operative period to 2-year follow up in Group A, from mean (SD) 1.82 (11.22) to 4.41 (9.73) degrees and 4.09 (5.32) to 7.36 (5.24) degrees, P = 0.047 and <0.0001, respectively. Group A had statistical significant less complications as zero vs 5, P = 0.049. CONCLUSION: The screw fixation alone seems to provide inferior stability of posterior facet fixation and calcaneal varus reduction with lower complication rates compared to screw with small-locking plate fixation. LEVEL OF EVIDENCE: Level III, Therapeutic Study.

Müller-Weiss Disease: The Descriptive Factors of Failure Conservative Treatment.

BACKGROUND: Conservative treatment is the first-line approach for Müller-Weiss disease (MWD). However, factors associated with the failure of conservative treatment have never been reported. Our objectives were to compare the differences in demographic and radiographic parameters between "successful" and "failure" conservative treatment in patients with MWD and identify descriptive factors associated with failure conservative treatment. METHODS: We retrospectively reviewed 68 patients with MWD divided into 29 "failure" and 39 "successful" conservative treatment groups. Demographic characteristics, Foot and Ankle Outcome Score (FAOS), visual analog scale (VAS) scores for pain and walking disability, and radiographic parameters such as calcaneal pitch, lateral Meary, anteroposterior (AP) Meary angle, and talonavicular-naviculocuneiform arthritis were compared. Logistic regression analysis was performed to identify descriptive factors of failure conservative treatment. A P value <.05 was considered a statistically significant difference. RESULTS: We found more severe VAS pain and walking disability scores and FAOS for the pain, activities of daily living, and quality of life subscales in the failure group (P < .05). Regression analysis demonstrated 2 significant descriptive factors associated with failure conservative treatment: abducted AP Meary angle >13.0 degrees and radiographic talonavicular arthritis. No demographic characteristics were found to be associated with failure conservative treatment. CONCLUSION: Midfoot abduction (AP Meary angle, >13 degrees) and radiographic talonavicular arthritis were factors associated with failure conservative treatment in MWD and should be determined concurrently with the clinical severity. Classification systems for MWD should include these factors. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Local Ketorolac Injection vs Popliteal Sciatic Nerve Blockade as an Adjuvant to a Spinal Block in Hindfoot Arthrodesis.

BACKGROUND: Popliteal nerve blocks reduce pain and markedly improve postoperative outcomes during foot and ankle surgery; however, several potential complications may arise from nerve block procedures. The purpose of this study was to investigate local infiltration analgesia with ketorolac as a convenient alternative for pain relief. METHODS: A total of 80 patients scheduled for hindfoot arthrodesis were randomly allocated to one of 2 anesthetic groups: a spinal block augmented with either a popliteal nerve block (n = 40) or local ketorolac and Marcaine infiltration (n = 40). Clinical assessment included postoperative visual analog scale (VAS) pain scores at 4, 8, 12, 24, and 48 hours, total morphine consumption, time to incision (time in operating room to incision), operative time, length of hospital stay, and complications. RESULTS: Despite similar morphine consumption between groups (P = .28), VAS scores were significantly lower at 24 hours (1.6 ± 2.2 cm vs 2.7 ± 3.0 cm, P = .01) and 48 hours (0.2 ± 0.7 cm vs 1.0 ± 1.5 cm, P < .01) after surgery using local ketorolac injection. Although time from entry into the operating room to incision was also reduced after local ketorolac injection (19.0 ± 5.3 minutes vs 31.4 ± 14.6 minutes, P < .001), the length of operative time (P = .38), hospital stay (P = .43), and number of complications (P = .24) were similar between groups. CONCLUSION: Ketorolac local injection provided effective pain control in hindfoot arthrodesis and markedly reduced VAS pain scores up to 48 hours after surgery compared with popliteal nerve block. In addition, ketorolac local injection also reduced time in the operating room compared with popliteal nerve blockade. LEVEL OF EVIDENCE: Level 1, randomized controlled trial.

Rapid SARS-CoV-2 antigen detection assay in comparison with real-time RT-PCR assay for laboratory diagnosis of COVID-19 in Thailand.

BACKGROUND: The Coronavirus disease 2019 (COVID-19) pandemic continues to spread across the world. Hence, there is an urgent need for rapid, simple, and accurate tests to diagnose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Performance characteristics of the rapid SARS-CoV-2 antigen detection test should be evaluated and compared with the gold standard real-time reverse transcription-polymerase chain reaction (RT-PCR) test for diagnosis of COVID-19 cases. METHODS: The rapid SARS-CoV-2 antigen detection test, Standard™ Q COVID-19 Ag kit (SD Biosensor®, Republic of Korea), was compared with the real-time RT-PCR test, Allplex™ 2019-nCoV Assay (Seegene®, Korea) for detection of SARS-CoV-2 in respiratory specimens. Four hundred fifty-four respiratory samples (mainly nasopharyngeal and throat swabs) were obtained from COVID-19 suspected cases and contact individuals, including pre-operative patients at Siriraj Hospital, Bangkok, Thailand during March-May 2020. RESULTS: Of 454 respiratory samples, 60 (13.2%) were positive, and 394 (86.8%) were negative for SARS-CoV-2 RNA by real-time RT-PCR assay. The duration from onset to laboratory test in COVID-19 suspected cases and contact individuals ranged from 0 to 14 days with a median of 3 days. The rapid SARS-CoV-2 antigen detection test's sensitivity and specificity were 98.33% (95% CI, 91.06-99.96%) and 98.73% (95% CI, 97.06-99.59%), respectively. One false negative test result was from a sample with a high real-time RT-PCR cycle threshold (Ct), while five false positive test results were from specimens of pre-operative patients. CONCLUSIONS: The rapid assay for SARS-CoV-2 antigen detection showed comparable sensitivity and specificity with the real-time RT-PCR assay. Thus, there is a potential use of this rapid and simple SARS-CoV-2 antigen detection test as a screening assay.

Lateral column lengthening corrects hindfoot valgus in a cadaveric flatfoot model.

BACKGROUND: Adult-acquired flatfoot deformity requires a complex operative plan that often utilizes a number of procedures to correct deformity, at both the hindfoot and midfoot. A lateral column lengthening procedure is typically performed to correct abduction deformity across the talonavicular joint; however its effect on hindfoot alignment is not well understood, and overcorrecting the hindfoot deformity can lead to pain and revision surgeries. Therefore, understanding the effect of lateral column lengthening on hindfoot alignment is important for operative planning. The aim of this study was to demonstrate the effect of a lateral column lengthening osteotomy on hindfoot valgus in a simulated flatfoot model. METHODS: A flatfoot deformity was created in 12 lower limb cadaveric specimens. A step-cut lateral column lengthening osteotomy was performed and changes in hindfoot and midfoot alignment were measured using a motion capture system. RESULTS: The lateral column lengthening procedure corrected 60% of the hindfoot valgus deformity (P < .001). In addition, the abduction deformity at the midfoot was completely corrected with the procedure (P < .001). CONCLUSION: Our findings suggest that the lateral column lengthening procedure corrects hindfoot valgus, in addition to midfoot abduction, in a flatfoot deformity. CLINICAL RELEVANCE: Understanding the relative contribution of each operative procedure to the overall deformity correction in flatfoot reconstruction will allow surgeons to accurately correct the foot into a plantigrade position while minimizing the risk of overcorrection.

Graft shape affects midfoot correction and forefoot loading mechanics in lateral column lengthening osteotomies.

BACKGROUND: Adult acquired flatfoot deformity is characterized by midfoot abduction and collapse of the medial longitudinal arch. Lateral column lengthening osteotomies primarily correct the abduction deformity, but the effects of graft shape on deformity correction and forefoot loading are unclear. Therefore, the purpose of this study was to demonstrate the effect of graft shape and taper on deformity correction and forefoot loading mechanics in a cadaveric flatfoot model. METHODS: Flatfoot deformity was simulated in 18 cadaveric specimens. A lateral column lengthening osteotomy was performed using a triangular, trapezoidal, and rectangular graft for each specimen. During each testing condition, talonavicular joint angles and forefoot plantar pressures were measured. RESULTS: Each graft shape corrected abduction and dorsiflexion deformity at the talonavicular joint. Coronal plane correction was affected by graft shape, and the less tapered trapezoidal and rectangular grafts overloaded the lateral forefoot compared to the intact condition. The more tapered triangular graft did not cause a lateral shift in forefoot pressures. Forefoot plantar pressures were strongly correlated with talonavicular abduction correction (R (2) = .473, P < .001). CONCLUSION: Graft shape had no effect on the correction of talonavicular abduction or dorsiflexion but did influence coronal plane motion and forefoot loading mechanics. Also, overcorrecting the abduction deformity was predictive of increased lateral plantar pressures. CLINICAL RELEVANCE: Although overcorrection of the abduction deformity at the midfoot remains the primary determinant of lateral forefoot overload, utilizing a graft with a larger taper may lower the incidence of lateralized forefoot pressure following correction.

Posterior acetabular arc angle of the femoral head assesses instability of posterior fracture-dislocation of the hip.

PURPOSE: Unstable posterior fracture-dislocation of the hip is determined by the wall defect or acetabular fracture index. The unstable hip is a result of inadequate posterior acetabular coverage of the femoral head from the posterior acetabular wall fracture. In order to measure total posterior acetabular coverage of the femoral head and avoid using the contralateral acetabulum as a calculation reference, the posterior acetabular arc angle of the femoral head was measured to assess stability of posterior fracture-dislocation of the hip. METHODS: Using coronal computed tomography (CT) scan of the normal contralateral acetabulum at the level of the widest acetabular diameter and thinnest medial wall of 60 acetabular fractures, posterior acetabular arc angles of the femoral head in intact, 20 % and 50 % defects of posterior acetabular walls were measured. The angles were measured from the acetabular centre to the thinnest medial wall and to the top, inner cortex of 80 % and 50 % posterior acetabular walls. RESULTS: Average intact, 80 % and 50 % posterior acetabular walls were 33.82 ± 4.30, 26.88 ± 3.33 and 16.91 ± 2.15 mm which corresponded to 92.25 ± 11.34, 77.42 ± 10.04 and 50.63 ± 6.58° of posterior acetabular arc angles of the femoral head. The intraclass correlation coefficient (ICC) of the measurements including correlation of conversion of posterior acetabular wall depths to posterior acetabular arc angles of the femoral head were more than 0.82 and 0.89. CONCLUSIONS: The measurement technique of posterior acetabular arc angle of the femoral head has strong reliability. Therefore, stable or unstable posterior fracture-dislocation of the hip can be determined in terms of more than 77 degrees or less than 50 degrees of posterior acetabular arc angles of the femoral head instead of less than 20 % or more than 50 % posterior acetabular wall defect.