Sickle cell disease (SCD) is one of the most common inherited hemoglobin disorders worldwide, affecting more than 20–25 million individuals. Approximately 300,000–350,000 infants are born with SCD annually, with India contributing significantly to the global burden. Nearly 1.4 million individuals are affected in India, particularly in central and western states such as Maharashtra, Chhattisgarh, Madhya Pradesh, and Odisha, where carrier frequencies range from 10% to 40%. [1,2] SCD is characterized by chronic hemolytic anemia and recurrent vaso-occlusive episodes that lead to microvascular obstruction, tissue ischemia, and progressive organ damage. Avascular necrosis (AVN) of the femoral head is a major musculoskeletal complication, affecting approximately 10–30% of patients and causing severe pain and disability.[3] Patients with SCD often develop AVN during the second or third decade of life, resulting in early degeneration of the hip joint. Once femoral head collapse occurs, total hip arthroplasty (THA) remains the most effective treatment for restoring function and relieving pain. However, THA in SCD patients is technically challenging because of medullary sclerosis, narrow femoral canals, osteopenia, bone infarction, and increased risk of perioperative complications. [4,5] Recent advances in implant design, perioperative transfusion protocols, anesthesia, and rehabilitation have substantially improved surgical outcomes, with implant survivorship reaching 85–95% at 10 years and lower complication rates than previously reported. [6,7] Assessment of functional recovery after THA is essential for evaluating treatment success. The Harris Hip Score (HHS) is a clinician-based tool that assesses pain and hip function, whereas the Hip Disability and Osteoarthritis Outcome Score (HOOS) is a patient-reported measure evaluating symptoms, daily activities, sports function, and quality of life. Comparative evidence regarding these scoring systems in patients with SCD is limited. [8–10] Therefore, the present study was undertaken to assess and compare postoperative functional outcomes of total hip arthroplasty in patients with sickle cell disease using the Harris Hip Score and the Hip Disability and Osteoarthritis Outcome Score.

This hospital-based analytical cross-sectional study was conducted in the Department of Orthopaedics, Sri Aurobindo Medical College and Post Graduate Institute, Indore, Madhya Pradesh, India. The study was carried out over a period of 18 months, from June 1, 2024, to November 30, 2025, after obtaining approval from the Institutional Ethics Committee. A total of 30 patients with confirmed sickle cell disease (SCD) and avascular necrosis (AVN) of the femoral head undergoing primary total hip arthroplasty (THA) were enrolled after obtaining written informed consent. Inclusion Criteria  Age 18 years or older.  Confirmed diagnosis of sickle cell disease.  Radiologically confirmed avascular necrosis of the femoral head requiring primary total hip arthroplasty.  Provided written informed consent. Exclusion Criteria  Immobility due to any other musculoskeletal or neurological disorder.  Patients unwilling or unable to provide informed written consent. Methodology All procedures were performed by experienced orthopedic surgeons following standardized perioperative protocols. Every patient underwent detailed preoperative clinical evaluation, hematological and biochemical investigations, radiological assessment, and pre-anesthetic evaluation. Intravenous prophylactic antibiotics were administered one hour before surgery. All patients underwent primary uncemented total hip arthroplasty using the posterior (Southern-Moore) approach. Patients were positioned in the lateral decubitus position. Following exposure of the hip joint, femoral head resection was performed after femoral neck osteotomy. The acetabulum was sequentially reamed to achieve an optimal press-fit, and an appropriately sized uncemented acetabular component with a highly cross-linked polyethylene liner was implanted. The femoral canal was prepared using sequential reamers and broaches while maintaining appropriate femoral anteversion. Trial reduction was performed to assess implant stability, restoration of leg length, offset, and range of motion before implantation of the definitive femoral stem and prosthetic head. After confirming satisfactory stability, layered wound closure was performed with suction drain placement. All patients received standardized postoperative rehabilitation and physiotherapy protocols. Outcome Measures The primary outcomes were postoperative functional outcomes assessed using the Harris Hip Score (HHS) and the Hip Disability and Osteoarthritis Outcome Score (HOOS). Functional assessment was performed preoperatively and at 3 weeks, 6 weeks, 3 months, and 6 months following surgery. Secondary outcomes included postoperative complications such as superficial or deep surgical site infection, dislocation, periprosthetic fracture, implant loosening, sciatic nerve injury, thromboembolic events, and the need for revision surgery. Data Collection Baseline demographic and clinical characteristics, including age, sex, affected side, duration of symptoms, laboratory investigations, radiological findings, operative details, postoperative complications, and functional outcome scores, were recorded using a standardized case record form. Follow-up assessments were conducted at scheduled postoperative visits, and all findings were systematically documented. Statistical Analysis Data were entered into Microsoft Excel and analyzed using IBM SPSS Statistics version 25.0 (IBM Corp., Armonk, NY, USA). Continuous variables were expressed as mean ± standard deviation (SD), while categorical variables were presented as frequencies and percentages. Changes in Harris Hip Score and Hip Disability and Osteoarthritis Outcome Score during follow-up were analyzed using repeated-measures analysis of variance (ANOVA) or the Friedman test, depending on data distribution. Correlation between HHS and HOOS was assessed using Pearson's or Spearman's correlation coefficient, as appropriate. A two-tailed p-value <0.05 was considered statistically significant.

A total of 30 patients with sickle cell disease (SCD) and avascular necrosis of the femoral head who underwent primary total hip arthroplasty (THA) were included in the study. The mean age of the study population was 38.47 ± 11.26 years, with most patients belonging to the 31–40 years age group. Males constituted 56.7% of the study population. Right-sided involvement was slightly more common than left-sided disease, while bilateral involvement was observed in 13.3% of patients. Most patients presented within 6–12 months of symptom onset, and flexion deformity was the most frequent fixed hip deformity. [Table 1] Table 1. Baseline Demographic and Clinical Characteristics of Patients Undergoing Total Hip Arthroplasty (N = 30) Parameter Category n (%) / Mean ± SD Age (years) 18-30 6 (20.0) 31-40 10 (33.3) 41-50 7 (23.3) 51-60 5 (16.7) 61-70 2 (6.7) Mean age (years) Mean ± SD 38.47 ± 11.26 Gender Male 17 (56.7) Female 13 (43.3) Hip involved Right 14 (46.7) Left 12 (40.0) Bilateral 4 (13.3) Duration of symptoms <6 months 5 (16.7) 6-12 months 11 (36.7) 12-24 months 9 (30.0) >24 months 5 (16.7) Fixed hip deformity Flexion 11 (36.7) Abduction 5 (16.7) Adduction 4 (13.3) External rotation 3 (10.0) Internal rotation 2 (6.7) No deformity 5 (16.7) Functional outcomes assessed using the Harris Hip Score (HHS) and the Hip Disability and Osteoarthritis Outcome Score (HOOS) improved progressively throughout the follow-up period. The mean HHS increased from 42.38 ± 6.72 preoperatively to 84.18 ± 6.95 at 6 months (p<0.0001). Similarly, the mean HOOS improved from 52.76 ± 6.15 preoperatively to 87.63 ± 5.41 at the final follow-up (p<0.0001). When the two scoring systems were directly compared, the preoperative HHS (52.76 ± 6.15) was slightly higher than the preoperative HOOS (50.48 ± 5.92). During postoperative follow-up, HOOS demonstrated marginally higher scores than HHS at each interval; however, these differences were not statistically significant (p>0.05), indicating that both instruments showed comparable improvement following THA [Table 2, Figure 1]. Table 2. Functional Outcome Following Total Hip Arthroplasty Using Harris Hip Score and Hip Disability and Osteoarthritis Outcome Score Follow-up Harris Hip Score (Mean ± SD) HOOS (Mean ± SD) p-value Preoperative* 52.76 ± 6.15 50.48 ± 5.92 >0.05 3 Weeks 58.76 ± 6.81 61.34 ± 7.02 >0.05 6 Weeks 67.15 ± 6.74 69.89 ± 6.58 >0.05 3 Months 75.94 ± 6.08 78.42 ± 5.97 >0.05 6 Months 85.26 ± 5.63 87.63 ± 5.41 >0.05 *Preoperative HHS and HOOS values were compared between the two scoring systems. Substantial improvement in functional outcome categories was observed at the 6-month follow-up. According to the Harris Hip Score, the proportion of patients with poor hip function decreased from 86.7% preoperatively to 10.0% after surgery, while 46.7% achieved excellent outcomes. Similarly, according to the HOOS, 80.0% of patients were categorized as having poor function before surgery, whereas 60.0% achieved good or excellent outcomes at 6 months. Both scoring systems demonstrated statistically significant improvement following THA. Furthermore, the mean improvement from baseline to 6 months was 32.50 ± 6.94 points for HHS and 37.15 ± 6.73 points for HOOS, with both changes being highly significant (p<0.0001). [Table 3& Table 4] Table 3. Functional Outcome Categories Before Surgery and Six Months After Total Hip Arthroplasty According to Harris Hip Score and Hip Disability and Osteoarthritis Outcome Score Functional Category Harris Hip Score Pre-op n (%) Harris Hip Score 6 Months n (%) HOOS Pre-op n (%) HOOS 6 Months n (%) Poor 26 (86.7) 3 (10.0) 24 (80.0) 5 (16.7) Fair/Moderate 4 (13.3) 6 (20.0) 6 (20.0) 7 (23.3) Good 0 7 (23.3) 0 10 (33.3) Excellent 0 14 (46.7) 0 8 (26.7) P-value 0.003 0.00001 Table 4. Comparison of Mean Harris Hip Score and Hip Disability and Osteoarthritis Outcome Score Before Surgery and at Six Months Following Total Hip Arthroplasty Outcome Measure Preoperative 6 Months Mean Improvement P-value Harris Hip Score 52.76 ± 6.15 85.26 ± 5.63 32.50 ± 6.94 <0.0001 HOOS 50.48 ± 5.92 87.63 ± 5.41 37.15 ± 6.73 <0.0001 Postoperative complications were uncommon. Anterior thigh pain was the most frequently observed complication, occurring in 2 patients (6.7%). One patient (3.3%) each developed superficial surgical site infection, postoperative dislocation, and aseptic loosening. Overall, 25 patients (83.3%) experienced no postoperative complications, indicating a favorable safety profile of total hip arthroplasty in patients with sickle cell disease [Figure 2]

Avascular necrosis (AVN) of the femoral head is one of the most debilitating musculoskeletal complications of sickle cell disease (SCD), resulting from repeated vaso-occlusive episodes that compromise the blood supply to the femoral head. Progressive collapse of the femoral head leads to chronic pain, restricted mobility, and marked functional impairment, often necessitating total hip arthroplasty (THA) in young adults. Although THA is the treatment of choice for advanced disease, the procedure remains technically demanding because of poor bone quality, medullary sclerosis, narrow femoral canals, and an increased risk of perioperative complications. Nevertheless, advances in surgical techniques, implant design, perioperative optimization, and rehabilitation have considerably improved postoperative outcomes in this patient population. [7,11] The mean age of patients in the present study was 38.47 ± 11.26 years, with the highest proportion belonging to the 31-40 years age group. This relatively young age reflects the early onset of femoral head osteonecrosis in SCD, where repeated vaso-occlusive episodes progressively compromise the femoral head blood supply, leading to premature joint destruction. Similar observations were reported by Mohammed Lafi Al-Otaibi et al. [12], who found that most patients undergoing THA for SCD-related osteonecrosis were between 20 and 52 years of age. Likewise, Mohamed Zubair Farook et al.[13] reported a mean age of approximately 37 years among patients undergoing THA for osteonecrosis secondary to SCD. Furthermore, the systematic review by Ankush Mohabey et al.[11] demonstrated that the average age of patients undergoing THA for SCD ranged from 20 to 35 years across published studies, confirming that hip degeneration occurs considerably earlier than primary osteoarthritis in the general population. A slight male predominance was observed in the present study (56.7%), although sickle cell disease itself affects both sexes equally. Comparable gender distribution has been reported by Mohammed Lafi Al-Otaibi et al. [12] and Mohamed Zubair Farook et al. [13], who also noted a marginally higher proportion of male patients undergoing THA. This difference is more likely related to healthcare-seeking behavior, occupational activities, and severity of symptomatic disease rather than differences in disease prevalence. Right hip involvement was slightly more frequent than left-sided disease, while bilateral involvement was present in 13.3% of patients. Similar patterns have been described by Mohammed Lafi Al-Otaibi et al. [12] and Eustathios Kenanidis et al. [7], who reported that although osteonecrosis is frequently bilateral because of the systemic nature of SCD, surgery is often performed initially on the more symptomatic hip. Most patients presented after 6-12 months of symptoms, reflecting the chronic and progressive nature of femoral head osteonecrosis. Delayed presentation is commonly attributed to recurrent vaso-occlusive crises, gradual progression of pain, limited access to specialized orthopedic care, and prolonged conservative management. Similar observations have been reported by Mohammed Lafi Al-Otaibi et al. [12] and Mohamed Zubair Farook et al. [13]. Flexion deformity was the most common fixed deformity in the present study, followed by abduction and adduction deformities. These findings are consistent with advanced femoral head collapse and prolonged joint dysfunction, as also described by Mohammed Lafi Al-Otaibi et al. [12]. Functional recovery assessed using the Harris Hip Score showed a steady and statistically significant improvement throughout follow-up. The mean HHS increased from 52.76 ± 6.15 preoperatively to 59.82 ± 6.63 at 3 weeks, 68.42 ± 6.28 at 6 weeks, 76.86 ± 5.94 at 3 months, and 86.14 ± 5.31 at 6 months (p<0.0001). The marked improvement reflects substantial pain relief, restoration of hip function, and improved mobility following THA. These findings closely agree with those reported by Mohammed Lafi Al-Otaibi et al. [12], who demonstrated significant postoperative improvement in HHS among patients with SCD. Similar long-term functional gains following uncemented THA were also reported by Said et al.[14], while the systematic review by Eustathios Kenanidis et al.[7] concluded that THA consistently improves functional outcomes in patients with SCD despite the technical challenges associated with surgery. Analysis of HHS categories further demonstrated the effectiveness of THA. Before surgery, 86.7% of patients had poor hip function and none had good or excellent scores. By the 6-month follow-up, only 10.0% remained in the poor category, whereas 46.7% achieved excellent outcomes and 23.3% achieved good outcomes. This significant transition from poor preoperative function to predominantly good and excellent postoperative function (p=0.003) is comparable with findings reported by Mohammed Lafi Al-Otaibi et al.[12] and Ankush Mohabey et al.[11], both of whom highlighted the substantial functional benefits of THA in patients with SCD-associated osteonecrosis. The Hip Disability and Osteoarthritis Outcome Score (HOOS) also demonstrated progressive and statistically significant improvement during follow-up. Mean HOOS increased from 50.48 ± 5.92 preoperatively to 61.34 ± 7.02 at 3 weeks, 69.89 ± 6.58 at 6 weeks, 78.42 ± 5.97 at 3 months, and 87.63 ± 5.41 at 6 months (p<0.0001). These improvements indicate significant recovery in pain, activities of daily living, sports and recreational function, and hip-related quality of life. Similar postoperative improvements in HOOS have been demonstrated by Anna K. Nilsdotter et al.[10], who established the validity and responsiveness of HOOS following total hip replacement. Likewise, Finch DJ et al.[15] reported mean postoperative improvements of approximately 35-38 points, comparable to the improvement observed in the present study. Direct comparison between HHS and HOOS demonstrated that the preoperative HHS was marginally higher than HOOS, whereas HOOS showed slightly higher scores throughout postoperative follow-up. However, the differences between the two scoring systems were not statistically significant (p>0.05), suggesting that both instruments provide comparable assessment of postoperative recovery. The slightly greater postoperative improvement observed with HOOS may be explained by its ability to capture patient-perceived quality of life, participation in daily activities, and functional recovery more comprehensively than clinician-based scoring systems. Similar observations regarding the responsiveness of HOOS have been reported by Anna K. Nilsdotter et al.[10], while Finch DJet al.[15] also emphasized the usefulness of patient-reported outcome measures in assessing recovery following THA. The mean improvement from baseline to 6 months was 32.50 ± 6.94 points for HHS and 37.15 ± 6.73 points for HOOS, with both improvements being highly significant (p<0.0001). The greater improvement observed with HOOS further supports its sensitivity in evaluating patient-centered outcomes after THA. Similar improvements have been reported by Finch DJ et al.[15] and Ankush Mohabey et al.[11], who concluded that THA provides excellent functional recovery despite the higher surgical complexity associated with SCD. Postoperative complications were infrequent in the present study. Anterior thigh pain was the most common complication, occurring in 6.7% of patients, while superficial surgical site infection, dislocation, and aseptic loosening each occurred in 3.3% of patients. Importantly, 83.3% of patients experienced no postoperative complications. These findings compare favorably with those reported by Mohamed Zubair Farook et al.[13], Eustathios Kenanidis et al.[7], and Fareed F. Alfaya et al.[8], who identified infection, aseptic loosening, osteolysis, and revision surgery as the principal complications following THA in patients with SCD. The relatively low complication rate observed in the present study may be attributed to careful patient selection, perioperative optimization, modern implant technology, standardized surgical technique, and comprehensive postoperative rehabilitation. Overall, the findings of the present study demonstrate that total hip arthroplasty is an effective treatment for advanced avascular necrosis of the femoral head in patients with sickle cell disease. Both HHS and HOOS showed significant and progressive improvement throughout follow-up, with no significant difference between the two assessment tools. The low complication rate and substantial gains in functional recovery observed in the present study further support the use of THA as a reliable surgical option for restoring mobility, relieving pain, and improving quality of life in this challenging patient population.

Primary total hip arthroplasty in patients with sickle cell disease resulted in significant improvement in hip function, pain relief, and quality of life over the 6-month follow-up. Both the Harris Hip Score and Hip Disability and Osteoarthritis Outcome Score demonstrated progressive and statistically significant postoperative improvement, with HOOS showing slightly higher patient-perceived functional gains. Most patients achieved good to excellent outcomes, while postoperative complications were infrequent. These findings suggest that total hip arthroplasty is a safe and effective treatment for advanced avascular necrosis in sickle cell disease, and the combined use of HHS and HOOS provides a comprehensive assessment of postoperative recovery.

1. Acurio MT, Friedman RJ. Hip arthroplasty in patients with sickle-cell haemoglobinopathy. J Bone Joint Surg Br. 1992;74(3):367-71. 2. National Health Mission Maharashtra. Sickle Cell [Internet]. National Health Mission Maharashtra; 2025 Mar 15 [cited 2026 Aug 18]. 3. Bishop AR, Roberson JR, Eckman JR, Fleming LL. Total hip arthroplasty in patients who have sickle-cell hemoglobinopathy. J Bone Joint Surg Am. 1988;70(6):853-5. 4. Colah RB, Mukherjee MB, Martin S, Ghosh K. Sickle cell disease in India. Curr Opin Hematol. 2015;22(3):215-23. 5. Grosse SD, Odame I, Atrash HK, Amendah DD, Piel FB, Williams TN. Sickle cell disease in Africa: a neglected cause of early childhood mortality. Am J Prev Med. 2011;41(6):S398-405. 6. Harris WH. Traumatic arthritis of the hip after dislocation and acetabular fractures: treatment by mold arthroplasty. J Bone Joint Surg Am. 1969;51(4):737-55. 7. Kenanidis E, Kapriniotis K, Anagnostis P, Potoupnis M, Christofilopoulos P, Tsiridis E. Total hip arthroplasty in sickle cell disease: a systematic review. EFORT Open Rev. 2020;5(3):180-8. 8. Alfaya FF, Ghazy RM, Hammouda EA, Mahfouz AA, Faya HK, Asiri MAM, et al. Total hip arthroplasty complications in sickle cell disease: systematic review and meta-analysis. J Clin Med. 2024;13(14):4129. 9. Lanzkron S, Carroll CP, Haywood C. Mortality rates and age at death from sickle cell disease: U.S., 1979-2005. Public Health Rep. 2013;128(2):110-6. 10. Nilsdotter AK, Lohmander LS, Klässbo M, Roos EM. The hip disability and osteoarthritis outcome score (HOOS): validity and responsiveness in total hip replacement. BMC Musculoskelet Disord. 2003;4:10. 11. Mohabey A, Joseph JD, Joseph FK, Deshmukh K, Warjukar P, Gandhi AP. Total hip arthroplasty in sickle cell disease: a systematic review and meta-analysis of functional outcomes and complications. J Clin Orthop Trauma. 2025;67:103060. 12. Al-Otaibi ML, Waliullah S, Kumar V. Total hip replacement in sickle cell disease patients with avascular necrosis of head of femur: a retrospective observational study. Indian J Orthop. 2021;55(5):1225-31. 13. Farook MZ, Aqil A, Theodorides A, Tselentakis G, West RM, Spencer RF. Total hip arthroplasty in patients with sickle cell disease: a systematic review of the literature and survival analysis from a single centre. Int Orthop. 2019;43(1):79-89. 14. Said GZ, Farouk O, Said HG. Noncemented total hip arthroplasty in sickle-cell disease. Int Orthop. 2011;35(8):1149-55. 15. Finch DJ, Martin BI, Franklin PD, Magder LS, Pellegrini VD Jr. Patient-reported outcomes following total hip arthroplasty: a multicenter comparison based on surgical approaches. J Arthroplasty. 2020;35(4):1029-35.