Bilaterally primary cementless total hip arthroplasty in patients with ankylosing spondylitis

Dual-mobility with modular components for primary total hip arthroplasty in bilateral bony ankylosis of the hips: A case report

INTRODUCTION AND IMPORTANCE

Primary total hip arthroplasty (THA) is a procedure performed in the United States for a variety of indications, with operation rates slated to increase over 275 % by 2040 when compared to 2014 (Thilak et al., 2015). Dual-mobility (DM) implants have gained popularity in the United States since gaining approval in the early 2010s (Heckmann et al., 2020). It has been well reported that DM implants decrease the risk of dislocation after primary and revision THA (Vielpeau et al., 2011; Donovan et al., 2022; Heifner et al., 2023; Foissey et al., 2023; Schmidt et al., 2020; Neri et al., 2019).

CASE PRESENTATION

We present the case of a 33-year-old male with a suspected ankylosing spondylitis (AS) diagnosis and bilateral bony ankylosis of the hips who underwent staged THA with modular dual-mobility (MDM) implants. At one year post-operatively, the patient is walking without the use of an assistive device and reports a VAS pain score of 0 at rest and 2 with activity and HHS of 90.

CLINICAL DISCUSSION

Implant selection is important in this patient population due to the increased risk of dislocation. Contemporary reports reveal MDM implants have demonstrated a substantial reduction in dislocation risk compared to fixed-bearing implants in patients with a high risk of dislocation. We opted to place the acetabular component inside the safe zone to improve stability and use the dual-mobility prosthesis to achieve our desired range of motion.

CONCLUSION

The improved stability of DM implants allows for a greater range of acetabular positions in patients who have a highly unpredictable functional outcome at the time of surgery. Our preliminary results contribute to the growing list of indications for MDM total hip arthroplasty.

Long-term outcomes of converting fused hips to total hip arthroplasty are satisfactory: a systematic review and meta-analysis

Background

Although conversion arthroplasty of fused hips can relieve pain and provide patient satisfaction, long-term outcomes of total hip arthroplasty (THA) after hip fusion remain a subject of debate. This meta-analysis aimed to assess the effectiveness of THA for fused hips over a long period with concerns over potential complications.

Methods

A systematic search of five databases from 2000 until 2023 identified English studies evaluating THA for fused hips with at least 100 months of follow-up. Meta-analyses were conducted using random-effect models via the comprehensive meta-analysis software. Sensitivity analysis, in-depth meta-regression, Egger's test, and the trim-and-fill method were performed appropriately.

Results

The meta-analysis assessed 790 patients and 889 hips with a mean follow-up of 11 years. At the final follow-up, the mean Harris Hip Score (HHS) and leg length discrepancy (LLD) improved by 34.755 and 2.3 cm from the baseline, respectively. Regarding survival of hip fusion conversion to THA, most studies (88.8%) reported a 5-year implant survival rate of at least 90%, and the 15-year and 20-year implant survival rates, ranged between 80-90% and 70-90%, respectively. Subjective dissatisfaction with the conversion of hip fusion to THA was only 5.3%. Composite rates of revision, instability, and aseptic loosening were 13.6%, 3.8%, and 8.8%, respectively.

Conclusions

Conversion of fused hips to THA results in favourable long-term outcomes regarding HHS, LLD, survival rates, and subjective satisfaction, leading to improved quality of life in properly selected patients. However, the presence of complications should be considered when evaluating the overall success of the procedure.

Total hip arthroplasty has higher complication rates in stiff spine patients: a systematic review and network meta-analysis

BACKGROUND

Ankylosing spondylitis (AS) and spinal fusion (SF) classified as stiff spines have been associated with the increased rate of complications following total hip arthroplasty (THA). However, the differences between the two cohorts have inconsistent evidence.

METHODS

We searched for studies comparing complications among stiff spine patients, including SF and AS, who underwent THA in PubMed/MEDLINE, Embase, Cochrane CENTRAL, Web of Science, and Scopus until March 2021. Studies detailing rates of mechanical complications, aseptic loosening, dislocation, infection, and revisions were included. We performed network meta-analyses using frequentist random-effects models to compare differences between cohorts. We used P-score to rank the better exposure with the lowest complications.

RESULTS

Fourteen studies were included in the final analysis. A total of 740,042 patients were included in the systematic review and network meta-analysis. Mechanical complications were highest among SF patients (OR 2.33, 95% CI 1.86, 2.92, p < 0.05), followed by AS patients (OR 1.18, 95% CI 0.87, 1.61, p = 0.82) compared to controls. Long Spinal Fusions had the highest aseptic loosening (OR 2.33, 95% CI 1.83, 2.95, p < 0.05), dislocations (OR 3.25, 95% CI 2.58, 4.10, p < 0.05), infections (OR 2.14, 95% CI 1.73, 2.65, p < 0.05), and revisions (OR 5.25, 95% CI 2.23, 12.32, p < 0.05) compared to AS and controls. Our results suggested that SF with longer constructs may be associated with higher complications in THA patients.

CONCLUSIONS

THAs following SFs have higher mechanical complications, aseptic loosening, dislocations, and infections, especially with longer constructs. AS patients may have fewer complications compared to this cohort.

Cementless total hip arthroplasty for three different degrees of hip involved secondary to ankylosing spondylitis: an analysis of 195 hips

Background

Hip involved secondary to ankylosis spondylitis (AS) had a huge influence on hip function. Cementless total hip arthroplasty (THA) can improve hip function. However, no previous study compared the outcomes of THA for AS patients with three different degrees of hip involvement.

Methods

The 195 hips were retrospectively analyzed and divided into non-ankylosed group (group A, 94 hips), fibrous ankylosed group (group B, 49 hips), and bony ankylosed group (group C, 52 hips). postoperative range of motion (ROM), harris hip scores (HHS), the short-form 12 health survey (SF-12), length of stay (LOS), cost, radiological assessments, and complications were compared.

Results

The follow-up time was (79.4 ± 29.5) months for group A, (80.6 ± 28.9) months for group B, and (79.1 ± 28.9) months for group C (P = 0.966). Group A had the best postoperative hip ROM (P < 0.001), while group A and B can realize better HHS than group C (P < 0.001). The three groups had similar SF-12 postoperatively. For group A, LOS and cost for unilateral procedure were the least than that for group B and C (P = 0.003 and P = 0.001). Similar radiological assessments were achieved for three groups. 1 hip in group A encountered delay union of wound. 1 hip in group C encountered delay union of wound and dislocation and another patient encountered femoral fracture intraoperatively. 12 hips (12.8%) in group A, 6 hips (12.2%) in group B, and 6 hips (11.5%) in group C encountered asymptomatic heterotopic ossification (P = 0.977).

Conclusion

For AS patients with hip involvement, THA can improve hip ROM and function. THA for the non-ankylosed hip can realize the better hip function and postoperative ROM than ankylosed hip.

Peri-operative Morbidity Associated with Bilateral Hip Arthroplasty for Inflammatory Arthritis: Results from a Consecutive Series of 168 Hips

AIM

This study aims to assess the risks and peri-operative morbidity associated with a single-stage sequential bilateral hip arthroplasty (SBHA) when performed in patients with arthritis secondary to inflammatory arthropathy.

METHODS

Data of patients who underwent SBHA between 2012 and 2018 for inflammatory arthritis were extracted from a database, for peri-operative complications and functional improvement. SBHA for other causes was excluded.

RESULTS

Data of 84 consecutive patients with a mean age of 34.5 years were analyzed. The mean follow-up was 2.4 years. 66% had ankylosing spondylitis, while 14% had rheumatoid arthritis. 50% of the patients had bilateral fusion of the hips, and 34% had flexion deformity > 30°.None of the patients had peri-operative cardiac or pulmonary complications. 2.4% had per-operative hypotension (MAP < 50 mmHg) and 1.2% had desaturation (SpO₂ < 90%). The mean drop in hematocrit was 9.3%. While 31% did not require blood transfusion, 35% required more than 1 unit of blood. Patients with pre-operative PCV of > 36% had a significantly lower risk of being transfused > 1 unit of blood (p = 0.02). ICU admission was 6%-mostly for post-operative monitoring. While one patient had a local hematoma that needed a wash-out, there were no infections, dislocations, or mortality in these patients. The modified Harris hip score improved from a mean of 26.5-85. The mean hip flexion improved post-operatively from 32° to 92°.

CONCLUSIONS

SBHA for inflammatory arthritis can be performed with minimum complications in a multidisciplinary setting. Pre-operatively, PCV of > 36 is advised to reduce transfusion rates.

Synchronous or sequential cementless bilateral total hip arthroplasty for osseous ankylosed hips with ankylosing spondylitis

Background

Bilateral osseous ankylosed hips secondary to ankylosis spondylitis (AS) are relatively rare but impact the quality of life hugely. Cementless total hip arthroplasty (THA) for bilateral osseous ankylosed hips with AS is a challenging procedure. No previous literature compares the clinical outcomes of synchronous and sequential bilateral THA for these special patients.

Methods

23 patients (46 hips) were retrospectively analyzed and divided into bilateral THA synchronously (group A) and sequentially (group B). The clinical measurement, radiological assessments, and complications were compared. Independent sample T test was used for data analysis.

Results

Harris Hip Scores (HHS) improved greatly for both groups (P = 0.58) as well as the range of motion (P = 0.64). But group B can realize shorter time (3.6 ± 1.2 days) to walk for the first time postoperatively (P = 0.02). Group A needed more blood transfusions (P = 0.028). For group A, no statistical difference was found in the bilateral inclination of cup (IC) (P = 0.48) and femoral offset (FO) (P = 0.07). For group B, no statistical difference was observed in bilateral IC (P = 0.37) but in bilateral FO (P = 0.04). Group A showed the fewer difference of bilateral IC (P = 0.02), while comparative measurements were found for two groups in the difference of bilateral FO (P = 0.78) and leg length discrepancy (P = 0.83). For both groups, the total hospital expense for each patient was similar and almost all patients were very satisfied with the outcomes. For group A, one patient encountered femoral fracture intraoperatively and another patient encountered hip dislocation and delay union of wound. 3 hips from group A and 3 hips from group B encountered heterotopic ossification.

Conclusions

Our retrospective research demonstrated that cementless bilateral THA was a reliable treatment for osseous ankylosed hip due to AS. Synchronous and sequential bilateral THA can realize similarly satisfactory clinical outcomes and radiographic evaluation.

Lewinnek Safe Zone References are Frequently Misquoted

BACKGROUND

Optimal acetabular component orientation in total hip arthroplasty (THA) is a necessity in achieving a stable implant. Although there has been considerable debate in the literature concerning the safe zone, to date, there has not been any review to determine if these references are consistent with the definition applied by Lewinnek et al. in 1978. Therefore, this article aims to examine the available literature in the PubMed database to determine how often a correct reference to the safe zone as defined by Lewinnek was applied to discussions regarding THA.

METHODS

A search for literature in the PubMed database was performed for articles from 1978 to 2019. Search criteria included terms 'Lewinnek,' 'safe zone,' and 'total hip arthroplasty.' Exclusions included abstract-only articles, non-English articles, articles unrelated to THA, and those lacking full content.

RESULTS

A review of literature yielded 147 articles for inclusion. Overall, only 11% (17) cited the Lewinnek article correctly. Forty-five percent (66) of articles referenced measurements in the supine position, 18% (26) referenced other positions, and 37% (55) did not specify. Nineteen percent (28) reported measurements of the acetabular cup orthogonal to the anterior pelvic plane, while 73% (108) did not, and 7% (11) did not specify. Twenty-three percent (34) measured from computed tomography scans instead of other methods.

CONCLUSIONS

In the discussion of the safe zone regarding THA, only 11% of articles listed are consistent with the definition established by Lewinnek. This warrants further investigation into a consistent application of the term and its implications for THA implant stability and dislocation rates.

Effects of types and degrees of ankylosing spondylitis hip structural damages on post-total hip arthroplasty outcome measurements

To determine the effects of ankylosing spondylitis (AS)-associated hip damages on the outcome measurements after total hip arthroplasty (THA).The medical records of 122 patients with AS (181 hips) who underwent THA were retrospectively reviewed. The mean follow-up was 43.9 (32-129) months. The types and degrees of hip damages were evaluated by preoperative hip X-rays. The patients were grouped according to the satisfaction degree after the operation. Univariable and multivariable statistical analyses were conducted.The intraclass correlation coefficients for the assessment between the 2 reviewers in the study were 0.86 to 0.97. Cox regression showed that femoral head erosion severity had an effect on the recovery time of independent walking without crutches postoperatively (odds ratio = 1.467, 95% confidence interval: 1.050-2.409, P = .025). The mean time to recover independent walking in the severe femoral head erosion group was 7.3 ± 0.9 weeks, which was 4.6 ± 0.4 weeks longer than in the non-severe femoral head erosion group, as confirmed by the log-rank (Mantel-Cox) test (Chi-squared = 11.684, P = .001). The multivariable analysis showed that higher acetabular sclerosis scores correlated with lower postoperative dissatisfaction risk (odds ratio = 0.322, 95% confidence interval: 0.136-0.764). The multiple linear regression analysis showed that postoperative range of motion (ROM) improvement was affected by preoperative ROM of the hip, space narrowing degree, and ceramic-ceramic material for the weight-bearing surface (F = 179.81, P < .001), with preoperative ROM of the hip having the greatest impact.Severe femoral head erosion prolongs the recovery time of independent walking after THA. Acetabular sclerosis is not associated with poor outcomes in patients with AS-associated hip damage undergoing THA.

Surgical strategies in management of ankylosed bilateral hips and knees in crouched posture

A 26-year-old wheelchair-bound man was brought to our institute with progressive painful deformity of both lower limbs involving bilateral hip and knee for the past 5 years. The patient was wheelchair-bound for the past 18 months. He was only able to crawl to meet his locomotor demands. On examination, the patient was in a crouched posture with mild kyphosis at the thoracolumbar region and ankylosis of bilateral hip and knee in an unfavourable position. Radiological and serological evaluation diagnosed him to be a case of neglected ankylosing spondylosis. We planned for arthroplasty of the bilateral hip and knee for correcting his posture and to regain his locomotor ability. The severity of the deformity mandated extensive releases and the handling of neurovascular structures. Hence, a holistic treatment plan with various surgical strategies was devised to manage his deformities. The patient made a good recovery and regained his locomotor ability without any major complications at a 2-year follow-up.

Revision Total Hip Arthroplasty in Patients With Ankylosing Spondylitis: Long-Term Results

BACKGROUND

Ankylosing spondylitis (AS) is a common inflammatory spondyloarthropathy with hip involvement in 40% of patients. With the recent interest in the hip-spine interplay, the purpose of this study was to define the long-term outcomes of revision total hip arthroplasty (THA) in the setting of AS.

METHODS

174 hips in patients with AS treated with revision THA from 1969 to 2016 were identified. Mean age at revision THA was 53 years and 76% were male. Cumulative incidences of any re-revision, reoperation, and dislocation were calculated using a competing risk analysis. Mean follow-up was 13 years.

RESULTS

The cumulative incidence of any re-revision after index revision THA was 7% at 5 years and 36% at 20 years. Cumulative incidence of any reoperation was 9% at 5 years and 38% at 20 years. Cumulative incidence of dislocation was 6% at 5 years and 8% at 20 years. Revision THAs performed with contemporary implants (2000-2016) had a lower but statistically nonsignificant cumulative incidence of any re-revision when compared with historical implants (before 2000) at 5 years (5% vs 8%), 10 years (11% vs 18%), and 15 years (11% vs 38%) (hazard ratio, 0.47; 95% confidence interval, 0.17-1.33; P = .016).

CONCLUSION

In this large series of 174 revision THAs in patients with AS, the cumulative incidence of dislocation was 8% at 20 years. The 20-year cumulative incidence of any re-revision was 36%, which is similar to reported rates in patients with comparable demographic features without AS.

LEVEL OF EVIDENCE

Level IV.

Does the Femoral Head Size Influence Outcomes After Uncemented Total Hip Arthroplasty for Fused Hips? A Prospective Study in Ankylosing Spondylitis

BACKGROUND

Uncemented total hip arthroplasty (THA) with large size femoral heads have shown greater advantage with good stability, range of motion and decreased dislocation rate in ankylosing spondylitis (AS). Meticulous planning is needed to address the unique surgical challenges in such patients with fused hip and spinal deformity.

MATERIALS AND METHODS

Thirty fivefused hip joints in twenty-five AS patients who underwent uncemented THA (April 2014 to December 2016) were included in our prospective study and were followed up for a minimum period of 36 months. Pain relief, functional improvement and patient satisfaction were statistically assessed using "Visual Analogue Score" (VAS), "Harris Hip Score" (HHS) and "AJRI 10-Point Satisfaction Score" (A10PSS), respectively.

RESULTS

The overall mean preoperative VAS improved from 6.9 ± 1.5 to 1.5 ± 1, HHS improved from 50.0 ± 12 to 88.4 ± 7.8 and A10PSS improved from 2.2 ± 1.2 to 7.6 ± 0.8. Our study results were significant with zero dislocation and good functional score in comparison to the other available studies in literature. First subdivision study in AS patients with bilateral THA performed better than unilateral THA. Second subdivision study showed no significant statistical difference in terms of VAS, HHS, A10PSS and dislocation rate in relation to femoral head size between 32 mm, 36 mm and 40 mm.

CONCLUSION

Uncemented THA with large size femoral head equal or greater than 32 mm provides better stability and good functional outcome with less dislocation rate in comparison to older studies of literature with femoral head size less than 32 mm.

LEVEL OF EVIDENCE

A Level II study. (Data collected from the ongoing prospective study) (https://www.spine.org/Documents/LevelsofEvidenceFinal.pdf).

Robot-Assisted Total Hip Arthroplasty for Arthrodesed Hips

Background

Conversion of arthrodesed hips to total hip arthroplasty (THA) remains technically demanding. This study aims to evaluate the safety and efficacy of robot-assisted THA in arthrodesed hips.

Methods

We retrospectively analyzed 45 ankylosing spondylitis patients with hip arthrodesis in the Chinese PLA General Hospital between August 2018 and August 2019. All surgeries were carried out by one single surgeon. The patients were followed at 3 months after surgery. Gender, body mass index, angle of hip arthrodesis, operating time, intraoperative fluoroscopic times, postoperative length of hospitalization, cup positioning, postoperative leg length discrepancy, offset discrepancy, intraoperative and postoperative complications, and postoperative Harris Hip Score were collected for all patients.

Results

Twenty-two patients (35 hips) who underwent robot-assisted THA and 23 patients (37 hips) who underwent manual THA were enrolled in this study. There were no significant differences in demographics and arthrodesed angles between the two groups. The fluoroscopic times during manual THA were significantly higher than those during robot-assisted THA (2.16±1.61 vs 0.47±0.61, respectively, p=0.000). In the robotic group, the percentage of acetabular cups within the safe zone was significantly greater than in the manual group (94.29% vs 67.56%, respectively, p=0.042). For manual THA, the anteversions were significantly different between the left and right sides (21.14±7.86 vs 16.00±6.32, respectively, p=0.042); however, no such significant difference was found in robot-assisted THA.

Conclusion

Compared with manual THA for arthrodesed hips, robot-assisted THA had significant advantages in improving the frequency of achieving cup positioning within the target zone with diminished radiation dose and no increase in operating time.

The Influence of Pelvic Tilt on the Anteversion Angle of the Acetabular Prosthesis

The concept of the "safe area" of the acetabular prosthesis has a long history and has been recognized by many scholars. It is generally believed that postoperative hip dislocation rate is low, when the acetabular anteversion angle is placed in the range of 15° ± 10°. Despite this, hip dislocation is a common complication after total hip arthroplasty. In recent years, more and more scholars have paid attention to the influence of pelvic tilt on the acetabular anteversion angle. The concept of acetabular anteversion changes as the pelvic tilt changes, and is challenging the traditional acetabular prosthesis "safe area." This study summarized the potential influencing factors of pelvic tilt and discussed the influence of the phenomenon on the anteversion angle of total hip arthroplasty (THA) acetabular prosthesis based on the literature review. We conclude that from the supine position to standing, followed by sitting, the pelvis tends to move backward. Pelvic sagittal activity, lumbar disease (ankylosing spondylitis), lumbar fusion (lumbar fusion, spine-pelvic fusion), and other factors related to the tilt are THA risk factors for postoperative dislocation and revision. With the change of body position, the degree of acetabular anteversion is directly related to the degree of pelvic tilt. The acetabular anteversion varies greatly, which leads to increased hip prosthesis wear and even hip dislocation. The lateral X-ray of the spine and pelvis is recommended in supine, standing, and sitting positions before THA. In addition, the pelvic tilt should be regarded as a reference of the acetabular prosthesis in the preoperative planning of THA.

Total hip arthroplasty by direct anterior approach in the lateral position for the treatment of ankylosed hips

OBJECTIVE

To investigate the clinical efficacy of total hip arthroplasty (THA) via the direct anterior approach (DAA) for the treatment of hip ankylosis in the lateral position.

METHODS

A retrospective analysis was performed on the clinical data of 24 patients (39 hips) who underwent THA via the DAA in the lateral position for the treatment of hip ankylosis between January 2016 and December 2018. We performed bilateral THA for fifteen patients and unilateral THA for nine patients. Operation time, intraoperative blood loss, length of incisions, straight leg-raising time, length of postoperative hospital stay, operation-related complication, prosthesis position, radiological outcomes, postoperative pain relief (evaluated by VAS) and functional rehabilitation [evaluated by Harris hip score and range of motion (ROM)] were analyzed to determine clinical efficacy. These clinical data were compared and statistically analyzed with the clinical data of another 23 patients (28 hips) who underwent THA via the posterolateral approach (PLA) for the treatment of hip ankylosis in the lateral position.

RESULTS

Follow-up was performed at 12-15 months. The incision length in the DAA group and the PLA group was (11.12 ± 1.69 vs. 14.36 ± 3.42) cm, the intraoperative blood loss was (371.25 ± 120.55 vs. 396.80 ± 101.21) ml, the operation time was (122.47 ± 25.40 vs. 138.47 ± 24.45) min, the postoperative hospital stay was (9.59 ± 4.62 vs. 12.08 ± 3.58) days, and the straight leg elevation time was (9.20 ± 2.12 vs. 12.34 ± 3.25) days, respectively. The prosthesis of the two groups was in a good position: The average angle of cup anteversion in the DAA group and the PLA group was (10.76 ± 2.84 vs. 15.36 ± 3.42)°, and the average angle of cup abduction in the DAA group and the PLA group was (40.00 ± 3.45 vs. 41.21 ± 2.85)° (P > 0.05). The VAS score, ROM and Harris score at different follow-up time points were significantly improved in the two groups compared with those before surgery. In the first 3 months after surgery, the VAS score, ROM and Harris score of the DAA group were significantly better than those of the PLA group (P < 0.05), but with the extension of the follow-up time, there was no significant difference in the above indicators between the two groups (P > 0.05). One case of greater trochanteric fracture occurred in the DAA group. Two cases of hip posterior dislocations occurred in the PLA group, and no dislocations occurred after manual closed reduction and hip fixation in bed for 1 month to the last follow-up. No complications such as infection, deep vein thrombosis, fat embolism, prosthesis loosening, limb length inequality or joint dislocation were reported.

CONCLUSION

THA via the DAA for the treatment of hip ankylosis in the lateral position was safe and effective and had the advantage of reduced trauma, quicker recovery of hip function, lower incidence of postoperative dislocation and ability to expose the acetabulum fully and fit the prosthesis properly, providing satisfactory clinical efficacy.

Bilateral total hip arthroplasty in ankylosing spondylitis: a systematic review

Ankylosing Spondylitis (AS) can commonly involve the hip joint and cause significant mobility problems. Total hip arthroplasty (THA) on a single side alone will not restore mobility in patients with bilateral disease.We performed a systematic review of the available literature to determine the changes in objective outcome measures and complications of bilateral THA in patients with advanced AS. Four studies, a total of 114 THAs, were included in the study. The average patient age was 32.9 years and the average follow-up time was 59.5 months.All studies reported a significant improvement in hip function, patient satisfaction and patient mobility following bilateral THA. Harris Hip Score (HHS) improved by a mean of 60.6 points post-operatively.Complications included five intra-operative fractures (4.4%) and three transient nerve palsies (2.6%). There were two dislocations (1.8%) that were successfully managed with closed reduction. Seven hips required revision, with the most common cause being aseptic loosening. Twelve hips (10.5%) developed heterotopic ossification consistent with Brooker Class 1 or 2 with no reports of re-ankylosis.This review suggests that bilateral THA is a safe and effective treatment of advanced hip disease in AS. Attention must be paid to the highly demanding technical aspects of this procedure to reduce the risk of significant complications.Debate still exists on the ideal prosthesis, fixation method and approach to use but this review presents data from several series of uncemented prostheses that have good post-operative results. Cite this article: EFORT Open Rev 2019;4:476-481. DOI: 10.1302/2058-5241.4.180047.

Ankylosing spondylitis: etiology, pathogenesis, and treatments

Ankylosing spondylitis (AS), a common type of spondyloarthropathy, is a chronic inflammatory autoimmune disease that mainly affects spine joints, causing severe, chronic pain; additionally, in more advanced cases, it can cause spine fusion. Significant progress in its pathophysiology and treatment has been achieved in the last decade. Immune cells and innate cytokines have been suggested to be crucial in the pathogenesis of AS, especially human leukocyte antigen (HLA)‑B27 and the interleukin‑23/17 axis. However, the pathogenesis of AS remains unclear. The current study reviewed the etiology and pathogenesis of AS, including genome-wide association studies and cytokine pathways. This study also summarized the current pharmaceutical and surgical treatment with a discussion of future potential therapies.

Complications of Total Hip Arthroplasty in Patients With Ankylosing Spondylitis

OBJECTIVE

To compare the risks of complications of primary total hip arthroplasty (THA) between patients with ankylosing spondylitis (AS) and those without AS.

METHODS

In this population-based study, we examined data from 1999 to 2013 of US Medicare beneficiaries (ages <75 years old) with AS and a comparison group without AS who had undergone primary THA. Complications were based on the Centers for Medicare & Medicaid Services 2013 THA Complication Measure, which included myocardial infarction, pneumonia, or sepsis within 7 days; surgical site bleeding, pulmonary embolus, or venous thrombosis within 30 days; or mechanical complications or local infection within 90 days. Mortality within 90 days, revision arthroplasty within 1 year, long length of stay, discharge to a care facility, and readmission within 90 days were also examined.

RESULTS

The study included 2,773 patients with AS and 107,341 patients without AS who had THA. Perioperative complications, 30-day complications, and local infections were rare in both groups (<1%). Mechanical complications and revision arthroplasty were uncommon in both groups. Ninety-day mortality was lower among patients with AS than those without AS (0.36% versus 0.7%). Patients with AS were more likely to be discharged to a care facility, and slightly more likely to have a long length of stay. Likelihood of a long stay was lower at hospitals that performed ≥100 THAs per year, but other complications were not associated with hospital volume.

CONCLUSION

Complications after primary THA are uncommon in patients with AS and similar in frequency to those without AS. Ninety-day mortality was lower among patients with AS.

[Functional outcomes of patients receiving total hip arthroplasty for ankylosing spondylitis]

OBJECTIVE

To assess the functional outcomes of patients undergoing total hip arthroplasty for ankylosing spondylitis (AS).

METHODS

Between March, 2013 and May, 2016, 75 AS patients with ankylosed hip (involving 92 hips) underwent unilateral biological artificial total hip arthroplasty. The patients were followed up for 12-24 months and the changes in VAS score of the affected hip were evaluated. The changes in the range of motion (ROM) of hip, employment, BASFI and BASDAI score, and Harris score were analyzed after the operations.

RESULTS

Significant improvements in general joint mobility, clinical symptoms and hip joint functions were achieved in all the patients. The average VAS score was significant reduced from 6.51± 1.32 preoperatively to 2.47±0.38 after the operation. Significant improvements were also achieved after the operation in the average Harris hip score (from 22.51±3.32 to 89.17±2.52), the total ROM (from 0 to 171.50±30.30), and mean BASFI score (from 6.2±2.6 to 2.3±1.2; all P < 0.05). At the final follow up, 42 hips showed excellent outcomes, 38 hips had good outcomes, and 12 hips had acceptable outcomes, with a good outcome rate of 87%. By 6 and 12 months after the operation, 6 and 32 of the 75 patients returned to work. No neurovascular injuries, infections or dislocations was found in the patients during the follow-up; 1 patient had prosthesis loosening found by X-ray ordered for complaint of pain in the affected hip 4 months postoperatively. Five patients had heterotopic ossifications, including 3 grade Ⅰ hips and 2 grade Ⅱ hips according to the Brooker grading system.

CONCLUSIONS

Biological artificial total hip arthroplasty is effective for treatment of ankylosing spondylitis with hip stiffness with good functional outcomes of the hip joint.

Comparison of Outcomes of Total Hip Arthroplasty between Patients with Ankylosing Spondylitis and Avascular Necrosis of the Femoral Head

BACKGROUND

The objective of this study was to compare clinical and radiological outcomes of total hip arthroplasty (THA) between ankylosing spondylitis (AS) of the hip joint and avascular necrosis (AVN) of the femoral head.

METHODS

Thirty patients (30 hips) underwent cementless THA for AS between 2003 and 2012. They were compared to 30 patients (30 hips) who underwent the same procedure for AVN of the femoral head. Each group was matched for age and gender, and both groups had similar preoperative demographic characteristics. All cases were followed for minimum 4 postoperative years. Clinical evaluation was based on operation time, intraoperative blood loss, quantity of postoperative drainage, Harris Hip Score (HHS), and range of motion (ROM). Radiological results were evaluated by acetabular cup anteversion and inclination, femoral stem orientation, pre- and postoperative leg length discrepancy, and postoperative complications.

RESULTS

The operation time was significantly longer in the AS group (120.2 ± 26.2 min) than in the AVN group (79.5 ± 11.1 min). The volume of postoperative drainage was significantly greater in the AS group (764.5 ± 355.4 mL vs. 510.5 ± 195.6 mL). Preoperative HHS was lower in the AS group (55.6 ± 13.8 vs. 59.2 ± 2.8). Similarly, postoperative HHS was significantly lower in the AS group (92.8 ± 2.7 vs. 97.4 ± 2.6). The arc of ROM was improved from 146.5° ± 13.2° preoperatively to 254.7° ± 17.2° postoperatively in the AS group and from 182.6° ± 15.5° to 260.4° ± 13.7° in the AVN group. Implant position and postoperative leg length discrepancy were not different between the groups. However, three cases of heterotopic ossification was observed in the AS group, whereas only 1 case was found in the AVN group. One deep infection and one aseptic stem loosening were found in the AS group, whereas none was observed in the AVN group.

CONCLUSIONS

Cementless THA showed satisfactory clinical and radiological results in both groups, despite the longer operation time, larger blood loss volume, and lower HHS score of the AS group. Our findings suggest that cementless THA is an effective and reliable treatment for both AS and AVN.

Ankylosing Spondylitis Increases Perioperative and Postoperative Complications After Total Hip Arthroplasty

BACKGROUND

Ankylosing spondylitis (AS) is a chronic autoimmune spondyloarthropathy that primarily affects the axial spine and hips. Progressive disease leads to pronounced spinal kyphosis, positive sagittal balance, and altered biomechanics. The purpose of this study is to determine the complication profile of patients with AS undergoing total hip arthroplasty (THA).

METHODS

The Medicare sample was searched from 2005 to 2012 yielding 1006 patients with AS who subsequently underwent THA. Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated for 90-day, 2-year, and the final postoperative follow-up for complications including hip dislocation, periprosthetic fracture, wound complication, revision THA, and postoperative infection.

RESULTS

Compared to controls, AS patients had an RR of 2.50 (CI, 1.04-5.99) of THA component breakage at 90-days post-operatively and 1.99 (CI, 1.10-3.59) at 2-years. The RR of periprosthetic hip dislocation was elevated at 90 days (1.44; CI, 0.93-2.22) and significantly increased at 2-years (1.67; CI, 1.25-2.23) and overall follow-up (1.49; CI, 1.14-1.93). Similarly, the RR for THA revision was elevated at 90-days (1.46; CI, 0.97-2.18) and significantly increased at 2-years (1.69; CI, 1.33-2.14) and overall follow-up (1.51; CI, 1.23-1.85).

CONCLUSION

Patients with AS are at increased risk for complications after THA. Altered biomechanics from a rigid, kyphotic spine place increased demand on the hip joints. The elevated perioperative and postoperative risks should be discussed preoperatively, and these patients may require increased preoperative medical optimization as well as possible changes in component selection and position to compensate for altered spinopelvic biomechanics.

Bilaterally Primary Cementless Total Hip Arthroplasty for Severe Hip Ankylosis with Ankylosing Spondylitis

OBJECTIVES

Total hip arthroplasty is a reliable therapeutic intervention in patients with ankylosing spondylitis, in whom the aims of surgery are to reduce pain, restore hip function and improve quality of life. The current study is a retrospective analysis of the clinical and radiographic findings in a consecutive series of patients with hip ankylosis associated with severe ankylosing spondylitis who underwent bilateral primary total hip arthroplasty using non-cemented components.

METHODS

From June 2008 to May 2012, total hip arthroplasty was performed on 34 hips in 17 patients with bilateral ankylosis caused by ankylosing spondylitis. The study patients included 13 men and 4 women with a mean age of 24.2 years. The mean duration of disease was 8.3 years and the average duration of hip involvement was 7.6 years. All patients had severe hip pain and dysfunction with bilateral bony ankylosis and no range of motion preoperatively and all underwent bilateral cementless total hip arthroplasty performed by a single surgeon. Joint pain, range of motion (ROM), and Harris hip scores were assessed to evaluate the postoperative results.

RESULTS

At a mean follow-up of 31.7 months, all patients had experienced significant clinical improvement in function, ROM, posture and ambulation. At the final follow-up, the mean postoperative flexion ROM was 134.4° compared with 0° preoperatively. Similar improvements were seen in hip abduction, adduction, internal rotation and external rotation. Postoperatively, 23 hips were completely pain-free, six had only occasional discomfort, three mild to moderate pain and two severe pain. The average Harris Hip Score improved from 23.7 preoperatively to 65.8 postoperatively. No stems had loosened at the final follow-up in any patient, nor had any revision surgery been required.

CONCLUSIONS

Bilateral severe hip ankylosis in patients with ankylosing spondylitis can be treated with cementless bilateral synchronous total hip arthroplasty, which can greatly improve hip joint function and relieve pain without significant complications. Provided the overall physical condition of a patient and their economic situation make surgery a feasible option and the surgeon is experienced, this treatment is a worthwhile surgical intervention for bilateral hip bony ankylosis. However, the technically demanding nature of the procedure and potential pre- and post-operative problems should not be underestimated.

Cementless total hip arthroplasty in patients with ankylosing spondylitis: A retrospective observational study

Controversies on the surgical protocols and efficacies of total hip arthroplasty (THA) in ankylosing spondylitis (AS) still exist. The aim of this study was to retrospectively analyze the perioperative managements and their outcomes related to performing THA on patients with AS.Data of 54 AS patients who underwent 81 THAs between 2008 and 2014 were retrospectively analyzed. Clinical and imaging data were collected preoperatively, postoperatively, and during the follow-up period for surgical efficacy.Using posterolateral approach, cementless prostheses were selected in all cases. Mean follow-up period was 3.6 years (range, 2-8 years). Inclinations and anteversions of acetabular cups were 36.3°±4.5° (range, 30°-50°) and 12.3°±4.9° (range, 0°-25°) respectively. Mean visual analog scale (VAS) score decreased from 6.7 ± 2.1 (range, 4-10) preoperatively to 1.5 ± 1.0 (range, 0-4) at final follow-up, and mean Harris hip score (HHS) improved from 31.2 ± 11.6 (range, 15-45) to 86.1 ± 4.3 (range, 80-95) (P < 0.05). Postoperative range of motion (ROM) in flexion was improved from 6.7°±13.5° (range, 0°-50°) preoperatively to 82.5°±6.4° (range, 70°-100°) at final follow-up, and ROM in extension was improved from 1.8°±5.7°(range, 0°-15°) to 15.4°±2.6° (range, 10°-20°) (P < 0.05). Heterotopic ossification (HO) was documented in 9 hips (11.1%). Signs of stable fibrous ingrowth and bone ingrowth were detected in 52 and 29 hips, respectively. Sciatic never injury was occurred in 3 cases, and treated conservatively. There were no signs of periprosthetic fractures, dislocation, or prosthesis loosening.Surgical efficacies of THA for AS patients with severe hip involvement are satisfactory.