Early results of primary THA performed in young adults (≤ 40 years) at a regional Saudi-Arabian orthopedics center. A Prospective Observational Study

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Introduction:

Total hip arthroplasty (THA) is considered the treatment of choice for end-stage degenerative disease of the hip joint and has been termed the surgery of the century due to its high success rate, patient satisfaction, and improvement in life quality (1, 2). The prevalence of THA procedures for hip deterioration in the USA increased by 50% from 1990 to 2002 and is expected to increase from 208,600 in 2005 to 572,000 in 2030 (3).

Although this procedure is commonly performed in relatively elderly populations (95% of primary THA in the UK are performed for patients older than 50 years) (4), more and more younger patients require THA due to various indications (5, 6), commonly hip avascular necrosis (AVN) and the sequel of developmental dysplasia of the hip (DDH), as reported in The 20th annual report from the National Joint Registry (NJR) of England (7).

Performing THA in relatively young patients could be the sole option for pain relief and mobility preservation in cases of advanced hip diseases or when medical management or joint preservation strategies fail (4, 8, 9). However, this procedure in younger patients can be challenging due to poor bone quality secondary to systemic disease or medications and osseous deformities that could complicate component placements (10). Despite improvements in surgical techniques, active young patients may have a higher risk of revision surgery than elderly patients because they are willing to engage in activities similar to those of their healthy peers after THA and the expected longer life expectancy (9, 11, 12).

Studies reporting the results of THA in young patients are scarce in our area, so the current study aimed to report the early experience and clinical results after performing THA in patients aged or younger than 40 years old from a regional Saudi Arabian hospital as a representative of the Arab (Middle Eastern) population.

Methods:

Study design

After obtaining ethical committee approval, we conducted a prospective observational study by following all patients who underwent primary THA over one year (between March 2018 and March 2019) at the orthopedics center in King Abdulaziz Specialist Hospital, Taif, Saudi Arabia.

Inclusion and exclusion criteria:

We included patients aged or under 40 years old regardless of the indication for THA, while patients above 40 years old, revision THA, and patients with incomplete data or follow-ups were excluded. Of 120 primary THAs performed during the study period, 29 patients met the inclusion criteria, and 25 were eligible for final inclusion.

Peri-operative protocol :

All patients underwent preoperative radiographic evaluation, including an Anterior-Posterior (AP) view of the pelvis (showing both hips) and AP and lateral views of the affected hip to confirm the diagnosis and perform preoperative planning, including assessing the leg length differences (LLD) by measuring the perpendicular distance from the inter-teardrop or the inter-ischial line to a fixed point at the middle of the lesser trochanter bilaterally.

All patients were operated upon by two senior surgeons under spinal anesthesia through either a posterolateral or modified direct lateral approach at the surgeons' discretion. The fixation types (cementless, cemented, or hybrid) were chosen based on the preoperative planning and the intraoperative surgeons' decision.

Postoperative and follow up protocol:

After the routine postoperative management of the patients in the recovery room supervised by the surgeon, an AP view of the pelvis, which included the entire stem length, was obtained. In the ward, patient-controlled analgesia was continued for the first 36-48 hours, and hemoglobin levels were checked on the first postoperative day. A blood transfusion was given if necessary. A broad-spectrum antibiotic (amoxicillin with clavulanic acid) 1gm every 8 hours for 24 hours postoperatively was given. Low molecular weight heparin (LMWH) was started 12 hours postoperatively every 24 hours (continued for three weeks).

Follow-up visits were scheduled at two weeks for sutures removal and initial wound evaluation; initial radiographic evaluation was performed at six weeks. Then, the follow-ups were at three, six, and 12 months, then annually. Harris Hip Score (HHS) was used for clinical evaluation of patients preoperatively and at follow up visits. The score is considered excellent if it ranges between 90 and 100, good between 80 and 90, fair between 70 and 80, and poor if below 70

Patients with sedentary occupations could return to work after six to eight weeks. They could return to occupations requiring limited lifting and bending at three months. The limited athletic activity was permitted, including swimming, cycling, and golfing. However, jogging, racquet sports, and other activities requiring repetitive impact loading or extremes of hip positioning were unwise. Patients were warned that such activities increase the risk of arthroplasty failure.   

Outcomes evaluation:

Basic demographic and clinical data, including age, gender, and occupation, were collected. Procedure details were recorded, including indication, laterality, type of prosthesis fixation, and bearing surfaces. Clinical evaluation per HHS was reported at the last follow-up visit and compared with preoperative scores. Radiographic evaluation (postoperatively and during follow-ups) was also performed to measure the LLD and compare it with the preoperative values, evaluate acetabular component inclination, and assess component migration (Figures 1,2, and 3). Any complications during the course of management were reported.

Statistical Analysis:

Statistical analysis was performed using SPSS version 20 (SPSS Inc., Chicago, Illinois). The results are presented as the mean ± SD or numbers and percentages. Non-parametric tests were used to compare the preoperative and last follow up values. P < 0.05 was considered statistically significant.

Results:

     Patients' demographics and Perioperative data:

A total of 25 patients (25 THAs) had a mean age of  31.6 ± 6.07 (ranging from 22 to 40), where 14 (56%) were males, 11 (44%) were females, 13 (52%) were either manual workers or had sedentary jobs while 12 (48%) were not able to work because of their hip disease. The left side was operated upon in 13 (52%) hips. The commonest indication for THA was advanced avascular necrosis (AVN), constituting 28%, followed by post-traumatic osteoarthritis (PTOA), 24%, and rheumatoid arthritis (RA) in 24%; details and complexities are shown in (Table 1).

The modified direct lateral approach was utilized in 23 (92%) THAs. Cementless fixation was used in 20 (80%) THAs, while cemented and hybrid fixation were utilized in three (12%) and two (8%) THAs, respectively. The bearing surface was Metal on Polyethylene (MOP) in 18 (72%) THAs, Ceramic on Polyethylene (COP) in five (20%), and Ceramic on Ceramic (COC) in two (8%). Post-operative blood transfusion was required in 11 (44%) patients.

Outcomes:

After a mean follow up of 20±4.5 months (ranging from 18 to 24), the HHS improved from a preoperative mean of  29.2±5.29 (ranging from 20 to 36) to a mean of 85.48±7.18 (ranging from 65 to 97) at the last follow up, p=0.0001. Excellent and good results were reported in 21 (84%) hips, while four (16%) had fair or poor results. All working patients (52%) reported returning to their jobs after THAs, while 10 out of the 12 non-workers preoperatively reported engagement in their pre-disease usual daily activities.

The mean acetabular cup inclination was 40.3±6.1 (ranging from 35.8 to 56.4). The LLD improved significantly from a preoperative mean of 2.12±1.01 cm (ranging from 0.64 to 4.66) to a last follow up a mean of 0.72±0.4 cm (ranging from 0 to 1.4), p=0.0001. No component migration was detected.

No intraoperative complications were reported; two (8%) had superficial wound infection at the time of suture removal, which was treated successfully by daily dressing and antibiotics; no loosening or infection was reported till the last follow up in any of the patients. None of the THAs required revision.    

Discussion:

Data regarding outcomes of THAs performed in the young population is considerably limited, as described by the joint replacement registries (7, 13); furthermore, results from our area are scarce.

In the current study, we achieved satisfactory functional outcomes, restoration of leg length equality, and return to pre-disease activity levels, with few complications and no early revisions in a small group of selected young arab patients who underwent primary THA for various indications.

Performing THA in relatively young patients is challenging owing to many variables; first is the patient's age, their need to get to their daily activities as early as possible, and the high possibility of future revision surgery due to the expected increase in their life span. Second, the THA indications, as most of these patients are presented with secondary hip pathologies such as PTOA and sequel of DDH or infection, as presented in the current series, could be associated with distorted anatomy, high hip center, bone deficiency, and increased risk of infection. Third, the necessity of a meticulous surgical technique to restore the hip biomechanics and the leg length, as well as the judicious selection of prosthesis fixation, which is sometimes challenging due to bone softening, such as in patients with RA, and proper selection of bearing surfaces to avoid early wear and aseptic loosening (5, 9, 13-17). All the previous factors and others contribute to the complexity of managing such patients.

Indications for THA in young patients changed over time and seem to differ among studies (17, 18). The most common indication for THA in our series was AVN, followed by RA or PTOA; this slightly differed from previous studies' indications. A study by Galloway et al. (4), including 110 patients, reported that the most common indication for patients younger than 40 years old in their series was a sequel of DDH, which was similar to Rahm et al., who reported that 144 primary THAs were performed in 127 patients younger than 40 years, and the most common indication for surgery was DDH as well (12). Furthermore, in even younger patients (below 21 years old), RA was the main indication for surgery (34.3%), followed by AVN and sequel of DDH, as reported in a recent systematic review by Huerfano et al. (9), after evaluating the results of 1166 primary THAs, which confirms the surgical indications diversity.

In the current study, we commonly used cementless implants (80%), similar to the results reported by Huerfano et al., where implant fixation varied among studies. However, the majority were cementless (70.6%), while cemented and hybrid fixation represented 22.6% and 6.7%, respectively (9). On the contrary, Rahm et al. reported that 66% of their patients received a cemented stem, while the acetabular cup was cementless in only 60% (12).

Various bearing surface options are available for THA in young patients, and proper selection is crucial in implant survival (17, 19). Swarup et al. investigated 548 THAs in patients having a mean age of 27 years (upper age limit was 35), followed up for a mean of 14 years; the bearing surfaces were MOP (61.2%), MOM (3.1%), COP (23.1%), and COC (12.6%), the revision rate of 23%, they reported a lower risk of revision for COC implants (HR 0.1) or COP implants (HR 0.47) compared to MOP implants (20). In the current study, 92% of the patients had either MOP or COP-bearing surfaces. Huerfano et al. reported that COC was the most frequently utilized (44%), followed by MOP (37.3%) in patients included in their systematic review (9).

Most of our patients (84%) achieved excellent or good functional outcomes per HHS, with a mean score of 85.48. Improved functional outcomes in younger patients who had THA for end-stage hip disease were reported as well by Chapot et al. where they even included younger patients (less than 20 years), and at a mean follow up of six years, the mean HHS was 81 (67% had excellent or good outcomes) (21). Furthermore, the negative effect of LLD on the functional outcomes after THA is well documented in the literature (22, 23); we were able to reduce the preoperative LLD from 2.12±1.01 cm to a last follow up mean of 0.72±0.4 cm (p=0.0001), which we believe it contributed to the better functional outcomes.

Galloway et al. (4) followed their patients for a median of 31 months; 18 out of 25 patients aged less than 30 years old (72%) returned to their pre-disease level of work; in the current study, 92% of the patients returned either to their pre-disease activity or work level.

We did not report any revisions in the current series, which could be attributed to the relatively short follow up period; however, given the fact that these are young and relatively active patients, they were consulted regarding the high possibility of future revision relying on the results reported by Bayliss et al., where they found that the lifetime revision risk after primary THA is about 5% for patients aged 70, while the incidence will increase to 35% for patients aged 50 years (15). In the systematic review by Huerfano et al. (9), the overall revision rate was 14.4%; of those, 63.6% were for aseptic loosening; furthermore, the 10-year survival rate was around 84.9%. Furthermore, Rahm et al. indicated that the revision risk is linked to the primary diagnosis, where they reported a higher risk of revision in patients diagnosed primarily as having DDH (OR 16.8) compared to other diagnoses (12).

We admit that the current study has several limitations. First, the small number of included patients which could be attributed to the high selectivity of specific age groups; furthermore, these were operated upon in a single center. Second, there is a relatively short follow-up period, where the long-term complications and revision incidence are not revealed. Last is the non-comparative study nature.

Conclusion:

In conclusion, primary THA is the option of choice for managing end-stage hip disease, even in younger patients when hip preservation surgeries are not valid. Our results showed improved functional outcomes and a return to pre-disease daily activities in most patients, with considerably lower complication incidence. However, more robust studies with a larger number of patients and a longer follow up period are needed to confirm the results obtained in our study. Furthermore, a need to perform a multi-center study to report the outcomes of THA performed in young patients from our area and to compare the results with studies published by other populations is highly suggested.

Об авторах

Walid M. Al-Shaer

Email: w_m_elshaer@yahoo.com
ORCID iD: 0009-0002-6883-4741
Саудовская Аравия

Ali Al-Yami

Email: Alyamia@yahoo.com
ORCID iD: 0000-0002-2446-4913
Саудовская Аравия

Mokhtar Al-Sayed

Email: dr_mokhtar86@hotmail.com
ORCID iD: 0000-0002-1431-3126
Саудовская Аравия

Ali Al-Zaidan

Email: Ali.m.alzaidan@gmail.com
ORCID iD: 0009-0005-7812-4649
Саудовская Аравия

Emad Al-Sufyani

Email: Emadruddah@gmail.com
ORCID iD: 0009-0003-8859-5589
Саудовская Аравия

Ahmed Khalifa

Email: ahmed_adel0391@med.svu.edu.eg
ORCID iD: 0000-0002-0710-6487
Египет

Raad Al-Thaqafi

Email: raadmatar977@gmail.com
ORCID iD: 0000-0001-9162-7754
Саудовская Аравия

Abdulmohsen Al-Hamyani

Email: Highest66@gmail.com
ORCID iD: 0009-0002-9998-9578
Саудовская Аравия

Mohammed Al-Subaie

Автор, ответственный за переписку.
Email: Dr_malsubaie@hotmail.com
ORCID iD: 0009-0007-5886-3465
Саудовская Аравия

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