Decision Making in Borderline Cases between Hip Preservation and Reconstruction Surgery

Abstract

The hip joint is the center of human body movement. An optimal hip function is critical for general health, mental health and well-being. A frequent dilemma in orthopedic practice is what to recommend to a patient with hip pain who is neither the ideal candidate for hip preservation surgery nor for total hip arthroplasty. What are the factors to be considered when deciding between a hip preservation or replacement surgery? This chapter aims to help orthopedic surgeons to decide between hip preservation or total hip arthroplasty as the primary surgery for borderline cases. Chondral damage, age, acetabular dysplasia, femoral torsion abnormality, lumbar spine disease, patient expectation, abnormalities in more than one hip layer, comorbidities, and psycho-social determinants are the main factors to be considered on decision-making for hip surgery. Conservative management, hip arthroscopy, hip osteotomy, and total hip arthroplasty can also be seen as a continuum of treatment.

1. Introduction

Orthopedic surgeons treating patients with hip disorders often see borderline cases between hip preservation surgery and total hip arthroplasty (THA). This scenario is becoming more frequent following the advancements in hip preservation surgery techniques in the last 3 decades.

Hip preservation surgery and THA may also be seen as a continuum of treatment. This approach is utilized in many clinical disorders in different medical fields. When treating heart failure, for example, cardiologists will try less invasive clinical and surgical approaches before proceeding with a heart transplant. As in prior times of technological advancement, hip preservation surgery and THA have progressed allowing for a better understanding of the complex hip-spine-pelvic-CORE anatomy and biomechanics of each of the five hip layers: the osteochondral, capsulolabral, musculotendinous, neurovascular, and kinematic chain, the interpretation of which is dependent on a comprehensive history and physical examination, with triplanar imaging assessment. Osseous conditions of the hip affect other hip layers in a cascading fashion.

The decision for borderline cases between preservation and reconstruction is complex, and the physician is intuitively considering multiple factors to be shared with patient. Frequently, a patient prefers the risk of a failed hip arthroscopy than the potential complications of a total hip arthroplasty. Therefore, the role of the orthopedic surgeon is to be well informed and make the decision with his patient. Similar cases based on imaging findings may require different approaches (conservative, hip preservation or THA) based on patient’s expectations.

The goal of this chapter is to organize factors and evidence to help the reader on the decision-making process for borderline cases between preservation and THA. This chapter does not aim to say what is right and what is wrong, it aims to help the reader to make the best decision for the patient based on the patient expectations. As an important reminder, the orthopedic surgeon is not required to make the decision in a single appointment, and repeat assessments are often the best way to define the most appropriate treatment approach for each patient. Repeat visits also helps to build relationship with patients, which is a key component in outcomes. The elements to be discussed in the current chapter are organized as in Table 1.

Degree of chondral disease Patient age Acetabular and femoral abnormalities Acetabular dysplasia Femoral torsion and acetabular version abnormalities Ischiofemoral impingement Presence of low back pain Other factors: Patient expectations Abnormalities in additional hip layers Contra-lateral hip disease Profession and physical activities Chronicity of pain Family support Commitment to rehabilitation Opioid use Comorbidities and psychological factors Physician-related factors

Table 1.

Factors to take into consideration to decide between hip preservation versus reconstruction surgery.

2. Degree of chondral damage

The degree of chondral damage is the first element to consider in borderline cases between hip preservation and reconstruction surgery. The results of hip preservation surgery are inferior in individuals with more advanced chondral disease [1]. The degree of chondral damage observed at the time of surgery is associated with risk of conversion to THA after hip arthroscopy. McCarthy et al. reported the likelihood of THA at a mean follow-up of 13 years after hip arthroscopy according to the cartilage disease observed arthroscopically [2]. Femoral head chondral damage was the strongest risk factor for conversion to THA. Hips with Outerbridge Grades III-IV disease at the femoral head were 58 times more likely to require conversion to THA when compared to Outerbridge Grades 0–2 [2]. Hips with acetabular cartilage disease Grade II-IV were 20 times more likely to require conversion to THA when compared to Outerbridge Grades 0–1. For patients who underwent THA, McCarthy et al. reported an average time of 4.8 years between the hip arthroscopy and THA [2]. Horisberger et al. reported the rate of conversion to THA in 20 patients with generalized degenerative changes at the hip joint observed during arthroscopy [3]. From 20 patients, 50% had undergone or planned to undergo a THA at a mean follow-up of 3 years. The mean time between the hip arthroscopy and THA was 1.4 years [3].

Preoperative imaging studies are helpful to estimate the risk of conversion to THA after hip preservation surgery [3, 4]. Hip joint space measurements on standing and supine pelvic radiographs have been shown to be equivalent by Bessa et al. [5]. Philippon et al. described that hips with joint space <2 mm at pre-operative radiograph were 39 times more likely to progress to a THA than those with ≥2 mm of joint space [6]. Larson et al. reported that 82% of the individuals with pre-operative joint space narrowing (>50% joint space narrowing compared to contra-lateral normal hip or ≤ 2 mm of joint space) failed to improve above 70 points on Harris Hip Score or underwent THA at a mean follow-up of 27 months. Zimmerer et al. studied the 11-year hip survivorship in 112 patients after primary hip arthroscopy according to the pre-operative Tönnis grade [4]. Conversion to THA was observed in 54% of the hips with Tönnis 2 or 3. In contrast, 14% of hips with no or minimal osteoarthritic changes on radiographs (Tönnis 0 or 1) underwent a THA following the primary hip arthroscopy at a mean follow-up of 11 years [4]. Modern techniques of labral repair may affect previously reported outcomes and need further studies.

Despite the usefulness of pre-operative imaging to estimate the degree of chondral damage, conventional radiographs and magnetic resonance imaging (MRI) underestimate the severity of chondral disease in 3 out of 4 patients with marked generalized chondral lesions [3]. For hips with more than 2 mm of joint space or Tönnis grade 0 and 1, Rosinsky et al. reported that narrower joint space was not correlated with intraoperative cartilage damage (Figure 1) [7]. The authors mentioned that narrower joint space (above 2 mm) may be an anatomic variant and cannot predict actual intraoperative cartilage damage [7].

Figure 1.

Imaging of a 67-year-old patient who was recommended total hip arthroplasty 1 year after hip arthroscopy. Femoral head chondral damage observed arthroscopically, despite preserved joint space pre-operatively. Figures A, B and C) radiographs demonstrating joint congruency and preserved joint space; D) arthroscopic image demonstrating the chondral damage at the femoral head (arrows); E and F) 10 months post-operative radiographs demonstrating lateral migration of the femoral head (yellow line) and subtle narrowing of the joint space; G and H) 10 months post-operative magnetic resonance imaging demonstrating the chondral damage with subchondral edema, not observed in the pre-operative MRI.

The frequent conversion to THA after hip preservation surgery in hips with advanced acetabular chondral damage at long term does not mean patients cannot benefit from hip preservation at short and mid-term. Peters et al. reported improved Harris hip scores from an average of 68 preoperatively to 91 at a mean follow-up of 26 months after open treatment for femoroacetabular impingement in 39 hips with Outerbridge grade 4 acetabular chondral damage [8]. Despite the good clinical outcomes, the authors described radiographic progression of osteoarthritis in 43% of the hips with Outerbridge grade 4 acetabular chondral damage [8]. The above paper reinforces that functional and clinical assessment are essential in association to radiographic evaluation when making clinical decisions for patients with degenerative changes at the hip. The effects of limited hip mobility on the lumbar spine and pelvis also need to be considered and will be discussed later in this chapter (Figure 2).

Figure 2.

Anteroposterior and lateral radiographs of a 53 years-old female with advanced left hip osteoarthritis and four years of conservative management including anti-inflammatory medication and intra-articular injection with corticosteroid. Modified Harris hip scores for the left hip is 93.5 out of 100.1. In contrast to the very satisfactory right Harris hip score, the Oswestry lumbar disability score has worsened from 8 to 16% in one year. This patient illustrates the importance of clinical assessment in association to imaging studies, as well as the effects of decreased hip mobility at the lumbar spine, when making clinical decisions for patients with hip diseases.

Hips with cam femoroacetabular impingement and advanced chondral damage often progress with anterosuperior migration of the femoral head to the cartilage defect. This finding has been recognized as a landmark for progressive osteoarthritic changes [9]. The anterosuperior migration of the femoral head is usually not evident on the anteroposterior or lateral radiographs. False profile of Lequesne radiographs and magnetic resonance are fundamental to identify the anterosuperior migration of the femoral head to the cartilage defect. The authors of the current chapter believe the migration of femoral head is a turning point on the progression of femoroacetabular impingement to be considered when recommending a hip preservation surgery. Hips with cam morphology and anterosuperior migration of the femoral head to the chondral defect are under the risk of further instability and rapid progression of osteoarthritis if undergoing a hip preservation surgery.

3. Age

The incidence of hip arthroscopy for older adults has grown exponentially along the last 2 decades. An increase of 280% in incidence of hip arthroscopy has been observed in the United States from 2005 to 2014 in the Medicare population, with 8100 primary hip arthroscopies performed [10].

Two variables are considered when studying hip arthroscopy results in older patients: 1) Improvement on functional scores; 2) Conversion rate to THA. A randomized controlled trial by Martin et al. compared hip arthroscopy and physical therapy versus physical therapy alone for patients older than 40 years with limited osteoarthritis (Tönnis grades 0–2) [11]. Arthroscopic acetabular labral repair with postoperative physical therapy led to better outcomes than physical therapy alone [11]. Martin et al. also reported a cross-over rate of 64% for patients from the non-surgical group to the hip arthroscopy group after 14 weeks, i.e., 64% of patients needed surgery after unsuccessful physical therapy [11]. Horner et al., in a systematic review published in 2017, concluded that patients over 40 years-old undergoing hip arthroscopy including femoral osteochondroplasty and labral repair presented clinically significant improvements in most research studies, whereas labral debridement did not produce clinically significant improvements postoperatively [12]. In a clinical scenario, the clinician should consider the difference in “normal” values for functional hip scores according to the age when making treatment recommendations or comparing results. Sharfman et al. compared the patient-reported outcomes measures among 3 different age groups for non-symptomatic individuals: <40 years, 40 to 60 years, and > 60 years [13]. The iHOT, mHHS, HOS-ADL, and HOS-Sport of these asymptomatic respondents all decreased in an age-dependent manner: iHOT (<40, 94.1; 40–60, 92.4; >60, 87.0), mHHS (<40, 94.8; 40–60, 91.3; >60, 89.1), HOS-ADL (<40, 98.4; 40–60, 95.0; >60, 90.9), and HOS-Sport (<40, 95.7; 40–60, 82.9; >60, 72.9) [13]. The authors stressed the importance of comparing a patient’s outcome scores with the age-normalized scores to establish an accurate reference frame with which to interpret outcomes [13]. In advancing age, the hip function grows in importance to maintain mental and general health.

The conversion rate to THA after hip arthroscopy is another factor to consider when recommending hip arthroscopy to older patients. According to Malik et al., the native hip was preserved at 2 years after surgery in 81.5% Medicare patients who underwent primary hip arthroscopy between 2005 and 2014 [10]. Patients >65 years had a 20% THA rate versus a 15% THA rate for below 65 years of age at 2 years after the hip arthroscopy [10]. Horner et al., in a systematic review, reported a rate of conversion to THA of 18.1% for patients 40 or older, 23.1% for patients over 50, and 25.2% for patients over 60 with a mean of 25.0 months to THA [12].

Age should not be used as an isolated criterium to recommend one or another hip treatment, since significant variability is observed among patients of same age in overall health status, comorbidities, physical activities, requirements, and patient’s expectations.

4. Acetabular and femoral abnormalities

Biomechanical abnormalities at the acetabulum and femur are a key factor to consider in borderline cases between hip preservation surgery or THA. Some biomechanical abnormalities contra-indicate or increase the risk of complications for hip arthroscopy and would be better addressed through osteotomy surgeries. However, an osteotomy surgery may not be a good option for a patient when considering the chondral damage, patient age and presence of low back pain. In addition, some patients will not be willing to undergo an osteotomy when considering the surgery magnitude and recovery. Therefore, acetabular and femoral biomechanical abnormalities will influence the decision on conservative management, hip arthroscopy, hip osteotomy or THA. These treatment option should be considered as a continuum of treatment for many patients, as more invasive procedures are recommended when less invasive interventions fail.

4.1 Acetabular dysplasia

The presence of acetabular dysplasia and its severity is to be considered before recommending a hip arthroscopy procedure versus other treatment options. Hip arthroscopy as isolated treatment for moderate to severe acetabular dysplasia has been associated with poor outcomes [14, 15]. However, hip arthroscopy with capsule repair has demonstrated good outcomes for patients with borderline hip dysplasia, traditionally described as lateral center-edge angle between 20° and 25° [16, 17]. Domb et al. reported the results of hip arthroscopy in 22 patients with lateral center-edge angle between 18° and 25°, and no or mild osteoarthritis (Tönnis grade 0 or 1) [16]. The authors utilized a combined imbrication and inferior capsular shift of the iliofemoral ligament to close the hip capsule arthroscopically. Good to excellent results were reported in 77% of the patients at a mean follow-up of 28 months, with 2 patients (9%) requiring revision surgery due to repeat sports injury or trauma [16]. The mean Tönnis angle of 5.8°, within normal limits, and the absence of significant osteoarthritis are important to consider on the results reported by Domb et al. [16]. Fukui et al. described the results of hip arthroscopy in 28 patients with lateral center-edge angle between 15° and 19°, at a mean follow-up of 42 months [17]. Five patients (18%) with a mean joint space <2 mm before hip arthroscopy underwent THA at a mean follow-up of 24 months after the hip arthroscopy [17]. Two patients (7%) required a periacetabular osteotomy to treat dysplasia after failure to improve following hip arthroscopy, while other two patients required a revision hip arthroscopy [17]. The mean Tönnis angle in patients who required periacetabular osteotomy after hip arthroscopy was 21°, while those not requiring PAO had a mean Tönnis angle of 15°. Fukuda et al. concluded that major surgery following hip arthroscopy is more likely for older patients, male, with more severe dysplasia, and with a larger alpha angle and decreased joint space [17]. Uchida et al. studied 28 patients with acetabular dysplasia who underwent hip arthroscopy [18]. The authors reported that patients with a broken Shenton line, femoral neck-shaft angle >140°, lateral center-edge angle <19°, or BMI >23 kg/m2 at the time of surgery are not good candidates for the arthroscopic management of acetabular dysplasia [18]. A major limitation of the studies by Domb, Fukui and Uchida et al. is the lack of consideration for the femoral torsion [16, 17]. Larson et al. reported inferior results of hip arthroscopy in 88 dysplastic hips when compared to non-dysplastic hips treated for femoroacetabular impingement [19]. The authors defined failure as a modified Harris Hip Score (mHHS) ≤70 or eventual pelvic/femoral osteotomy or total hip arthroplasty. At the time of final follow-up, the dysplastic cohort demonstrated a mean mHHS of 81.3 with a mean 15.6-point improvement in mHHS, compared with 88.4 and 24.4 points, respectively, in the femoroacetabular impingement cohort [19]. Larson et al. also reported that increased femoral torsion and psoas tenotomies did not influence the outcomes in hips with acetabular dysplasia [19].

Periacetabular osteotomy (PAO) is another option for patients with acetabular dysplasia that should be considered for some patients to preserve the hip joint, prolong the native hip life, or as a bridge to a THA. Studies on long term results have provided insight on when is too late for a PAO. Matheney et al. reported the outcomes of PAO in 135 hips at an average follow-up of 9 years [20]. Two independent predictors of failure (defined as arthroplasty or a high pain score) were identified: (1) an age of more than thirty-five years and (2) poor or fair preoperative joint congruency [20]. The probability of failure requiring arthroplasty was 14% for hips with no predictors of failure, 36% for those with one predictor (either an age of more than thirty-five years or poor or fair joint congruency), and 95% for those with both predictors [20]. Wells et al. reported the outcomes of PAO in 154 hips at an average of 10.3 years post-operatively [21]. One hundred and twenty-two hips (79%) did not undergo THA and did not have significant hip symptoms at the final follow-up [21]. A higher risk of failure was associated with fair or poor preoperative joint congruency and with overcorrection (a postoperative lateral center-edge angle of >38°) [21].

Association of hip arthroscopy and periacetabular osteotomy is another option of treatment for patients with acetabular dysplasia. Hip arthroscopy after a PAO surgery is required in 3.1–27% according to different authors [22, 23]. In patients with hip dysplasia who fail hip arthroscopy, PAO has been shown to be successful and results did not differ from patients who undergo PAO as index procedure [24].

A frequent question from patients is if undergoing a PAO or hip arthroscopy would decrease the chances of success for a THA procedure in the future. Considering THA after a PAO, the medical literature is controversial. Amanatullah et al. reported no difference in complication, revision rates or clinical results for THA in dysplastic patients with or without prior PAO [25]. Osawa et al. reported poorer clinical outcomes of THA in patients with prior PAO compared to dysplastic patients without PAO, although there was no difference in revision or complication between the groups [26]. Both studies observed increased rates of acetabular component malposition in hips with prior PAO [25, 26]. In regards to results of THA following hip arthroscopy, Lemme et al. reported that patients who underwent THA more than 1 year after hip arthroscopy were at no increased risk for surgical or medical complications [27]. However, increased risk of dislocation (OR 1.75; CI 1.05–2.87; P = .03) and aseptic loosening (OR 2.18; CI 1.06–4.49; P = .03) was observed if the THA was performed <1 year after the hip arthroscopy [27]. THA <1 year after hip arthroscopy was also associated with increased risk for needing revision THA at 2 years (OR 1.92; CI 1.07–3.36; P = .02) and 4 years (OR 2.05; CI 1.17–3.53; P = .01) after THA.

The severity of hip dysplasia is usually defined by the morphologic features of the acetabular roof. However, abnormalities of the acetabular horns and sagittal orientation of the acetabulum are also frequent and have not been studied regarding the results of hip preservation surgery. Further studies are necessary to define if hips with antero-inferior or posteroinferior acetabular undercoverage have inferior results with hip arthroscopic procedures (Figure 3). Abnormal acetabular slope (sagittal orientation of the acetabulum) is another factor that requires further investigation when recommending a preservation or reconstruction procedure (Figure 4).

Figure 3.

Antero-inferior hip instability. A and B) right hip with anteroinferior instability observed arthroscopically, with decreased anterior sector angle (ASA < 58°) and increased anterior horn angle (AHA > 50°); C and D) right hip with normal anterior acetabular horn morphology, with normal ASA and normal AHA. Reprinted from Hatem et al. Anteroinferior hip instability in flexion during dynamic arthroscopic examination is associated with abnormal anterior acetabular horn [28].

Figure 4.

Sagittal slice of a hip magnetic resonance arthrogram demonstrating the acetabular slope. (A) Hip with decreased acetabular slope (8°); B) hip with increased acetabular slope (33°). Reprinted from Hatem et al. spinopelvic parameters do not predict the sagittal orientation of the acetabulum [29].

4.2 Femoral torsion and acetabular version abnormalities

Assessment in three planes is a basic requirement for any project in engineering. The hip joint is a complex biomechanical construct, and evaluation in three anatomical planes should be completed before any surgical recommendation. The imaging assessment of the hip joint has historically neglected the axial plane due to the inherent limitations of radiographs. Currently, the broad availability of MRI and CT to orthopedic surgeons makes it difficult to justify the lack of imaging assessment in three anatomical planes (axial, coronal and sagittal). The femoral torsion is one of the hip parameters assessed in the axial plane and has not received the necessary attention by clinicians and researchers in the orthopedic field. Increased femoral torsion is associated with decreased extension and external rotation, and increased internal rotation of the hip [30, 31, 32, 33, 34, 35]. Decreased femoral torsion is associated with increased external rotation and decreased internal rotation of the hip [30, 31, 32, 33]. Effects of abnormal femoral torsion on the lumbopelvic biomechanics have also been reported, and can be estimated by the hip-spine extension and flexion tests on physical examination [36, 37].

A recent systematic review on the effect of acetabular version on outcomes of hip arthroscopy concluded that surgery in patients with acetabular retroversion resulted in no difference in functional outcomes compared with patients with normal acetabular version [38]. The medical literature has controversial results on the influence of femoral torsion on hip arthroscopy results. Fabricant et al. observed less improvement following hip arthroscopy in patients with <5° of femoral torsion compared with patients with normal and increased femoral torsion [39]. In contrast, two studies did not report decreased femoral torsion to be a negative prognostic factor for hip arthroscopy [40, 41]. Both studies did not include functional assessment of lumbar spine. Chaharbakhshi et al. reported that patients with combined borderline dysplasia and femoral torsion ≥20° demonstrated significant improvements after hip arthroscopy, despite the inferior results when compared with a control group with normal version and acetabular coverage [42]. Jackson et al. found that femoral torsion >18° was not a negative prognostic factor for hip arthroscopy [43]. Fabricant et al. described inferior results (modified Harris Hip Score) of hip arthroscopy with psoas tenotomy for patients with >25° of femoral torsion [44]. Part of the controversy on the results is explained by differences on how to measure femoral torsion among the studies and the definition of normal, increased or decreased femoral torsion. Most studies on the effect of femoral torsion on hip arthroscopy consider decreased femoral torsion as <5° and increased femoral torsion as >20° [38]. The method utilized for the measurement of the femoral torsion is to be considered for the purpose of comparison to other studies [45, 46, 47]. Increasing values for femoral torsion are observed by measuring the femoral neck orientation more distally, and differences of 10° or more among the methods are particularly frequent in patients with excessive femoral torsion [46]. Until the controversy is resolved, it is recommendable to assess femoral torsion and acetabular version for McKibbin’s index as routine for patients with hip symptoms.

Femoral derotation osteotomy is to be considered for patients with abnormal femoral torsion, particularly those with failed hip arthroscopy and with low back pain. Tönnis and Heinecke reported satisfactory results of PFDO in 17 patients with decreased femoral torsion and painful hip joints [31]. Another study showing improvement in hip function with PFDO was published by Buly et al., who reported a mean improvement of 27 points in the mHHS following 55 derotation osteotomies in 43 patients [48]. Hatem et al. reported 34 patients who underwent proximal femoral derotation osteotomy [37]. Improvement in the mHHS above the minimum clinically important difference (MCID) was observed in 33 hips (89%). In a subgroup of 14 consecutive patients assessed with Oswestry disability index (ODI), the ODI improved from a mean of 45% before the PFDO to 22% at final follow-up [37].

The orthopedic surgeon might consider that extreme values of femoral torsion will have higher biomechanical effects. Therefore, the influence of femoral torsion >30° or below 0° is more clinically significant than the normal range values presented in medical literature. Ligamentous structures play a role on the biomechanical effects of increased and decreased femoral torsion and further studies are needed to better understand the relationship between the iliofemoral ligament and femoral torsion. The patient body habitus and frame will have an influence on strain tolerance to abnormal femoral torsion. Physical examination is essential to determine the biomechanical effects of abnormal femoral torsion and to guide treatment, particularly testing gait in different hip rotation and the hip spine-extension test (Figure 5) [49]. The femoral torsion should be considered factor when deciding between hip preservation surgery and THA. In older patients, abnormal femoral torsion may add up to other negative prognostic factors towards a recommendation for THA.

Figure 5.

Hip-spine extension test. (A) the examined hip is brought into terminal hip extension in neutral abduction and rotation while the examiner observes the pelvis and lumbar spine; (B) a positive result is the recreation of low back pain with associated pelvic and lumbar movement in adaptation to the limited hip extension; (C) adding abduction to extension allows the hip to extend without secondary effects at the pelvis and lumbar spine in patients with ischiofemoral impingement; (D) adding internal rotation gives clearance for the extension of the hip in cases of increased femoral anteversion. Conversely, due to premature coupling, internal rotation increases the lumbar and pelvic accommodation in hips with decreased femoral version or retroversion; (E) adding external rotation gives clearance for the extension of the hip in cases of decreased femoral anteversion or retroversion. Conversely, due to premature coupling, external rotation increases the lumbar and pelvic accommodation in hips with increased femoral anteversion.

4.3 Ischiofemoral impingement

Ischiofemoral impingement is associated with limitation in hip extension. A more aggressive treatment approach may be recommended for individuals with secondary biomechanical effects of ischiofemoral impingement as low back and pelvic pain. Gómez-Hoyos et al. simulated a hip extension deficit with an ischiofemoral impingement model to evaluate a primary hip-spine effect due to the limited terminal hip extension produced by the hip pathology [50]. Resultant data described significant increase in lumbar facet joint loading during the impingement state, as compared to the native state for L3-L4 and L4-L5 spine segments. An average 30% increase in facet joint overload was observed between impinged state and native state [50].

Conservative treatment for ischiofemoral impingement includes avoidance of impingement positions, correction of leg length inequality, abductor strengthening, correction of foot hyperpronation and guided injections. Surgical treatment options are indicated when conservative treatment is insufficient: endoscopic lesser trochanter plasty and resection; open lesser trochanter resection; ischioplasty; distal transfer of the lesser trochanter; proximal femoral osteotomy -varus and derotation osteotomy; and finally total hip arthroplasty. The orthopedic surgeon should consider the presence of ischiofemoral impingement in borderline cases between hip preservation surgery and THA. Individuals with ischiofemoral impingement and associated advanced chondral damage of the hip joint are better suited for THA. Total hip arthroplasty is also an alternative to address ischiofemoral impingement in hips with mechanical failure from multiple biomechanical abnormalities, including hip dysplasia and abnormal femoral torsion. A posterior approach allows the repair of hamstring avulsion at the ischial tuberosity, often observed as a result from the ischiofemoral impingement. The presence of contra-lateral hip disease, knee osteoarthritis, and lumbar spine abnormalities reinforce the indication of total hip arthroplasty to treat ischiofemoral impingement. The orthopedic surgeon performing a hip joint replacement in individuals with IFI must be aware of all parameters in the coronal, axial and sagittal planes for the correction of all biomechanical abnormalities. Testing hip extension intra-operatively is fundamental in patients with IFI undergoing total hip arthroplasty through either anterior, lateral or posterior approach.

5. Presence of low back pain

Hip reconstruction surgery has the potential to restore hip mobility to normal levels and remove the secondary effects of limited hip motion on the lumbar spine. Improvement in low back pain after THA has been consistently reported. Parvizi et al. studied 170 patients with low back pain prior to undergoing THA [51]. Postoperatively, 66% (113) patients reported complete resolution of low back pain [51]. Of the 57 patients whose back pain did not resolve postoperatively, 38 had prior suspected or diagnosed spine disorders [51]. Chimenti et al. reported that 60.5% of patients who underwent THA had at least mild back pain preoperatively, and 58.4% of these patients experienced improvement in low back pain of at least 1 degree difference (e.g. moderate to mild) [52]. Notably, 80% of patients who indicated severe low back pain preoperatively showed some degree of pain improvement after THA [52]. Okuzu et al. reported that low back pain improved in 62.9% of patients after THA [53]. Persistent low back pain in the remaining 37.1% of patients after THA was shown to be associated with biomechanical abnormalities of the spine, such as sagittal spinal imbalance and high Cobb angle [53]. A study by Ran et al. examined changes in low back pain after THA in patients with lumbar degenerative disease, and observed a decreased on VAS for pain from 4.13 ± 1.37 preoperatively to 1.90 ± 1.44 postoperatively [54].

Patients with existing spinal pathologies present higher rates of complications after THA. Blizzard et al. conducted a review of the Medicare Standard Analytical Files from 2005 to 2012 [55]. The authors reported that patients with lumbosacral spondylosis, lumbar disc herniation, lumbar degenerative disc disease, and spondylolisthesis prior to THA had increased risk of post-operative complications such as prosthetic joint dislocation, periprosthetic fractures, periprosthetic infections, early revision THA, and wound complications [55].

Less evidence is available on hip preservation surgery and low back pain. Beck et al. reported that patients with a history of lumbosacral pathology (i.e. stenosis, fracture, prior surgery, and disc pathology) had significantly lower Hip Outcome Scores (activities of daily living subscale and sports subscale), modified Harris Hip Score, and visual analog scale pain two years after hip arthroscopy [56]. In contrast, in a cohort of 48 elite athletes with low back pain who underwent hip arthroscopy, Jiminez et al. reported that 79% did not report low back pain postoperatively at a mean follow-up of 53 months [57]. Endoscopic treatment for ischiofemoral impingement has also been associated with improvement in low back pain. Hatem et al. studied 31 patients with ischiofemoral impingement and low back pain who were treated with endoscopic partial lesser trochanter resection [58]. The authors reported a decrease in low back pain above the minimal clinically important difference in 2 of 3 patients after partial resection of the lesser trochanter [58]. Surgical correction of abnormal femoral torsion with derotation osteotomy has also been associated with improvement in low back pain. Hatem et al. reported that 14 patients with abnormal femoral torsion and LBP who underwent femoral derotation osteotomy demonstrated improved Oswestry disability index scores from 45% ± 16% (mean ± SD) before the PFDO to 22% ± 17% (mean ± SD) at mean follow-up of 24 months [37]. Nine (64.3%) of the 14 patients presented improvement in the Oswestry disability index above the minimal clinically important difference [37].

6. Other factors

The decision between hip preservation surgery and THA for borderline cases is also influenced by the following factors barely addressed in medical literature: patient expectations, abnormalities in additional hip layers, contra-lateral hip disease, profession and physical activities, commitment to rehabilitation, family support, chronicity of pain, opioid use, comorbidities, and physician-related aspects. Despite the lack of scientific evidence on those factors, the authors of the current chapter decided to share their impressions after combined decades of experience on deciding if conservative treatment, hip preservation surgery, or THA would be the most appropriate.

The concept of hip layers is very useful for the orthopedic surgeon to identify and organize diagnosis in patients with hip abnormalities, and to relate those to the patient expectations. The hip abnormalities can be categorized in the following layers: osteochondral, capsulolabral, musculotendinous, neurovascular, and kinematic chain. The fifth layer represents the link between the hip, pelvis, lumbar spine, CORE and distal lower extremity. Most patients with hip symptoms will have problems in more than one layer, which can be related or unrelated. For example, patients with acetabular dysplasia often have associated gluteus medius and minimus tendinitis as result of excess work required from the abductors. The correction of the osseous abnormalities may or not result in improvement of the conditions in other layers. Each diagnosis and potential improvement or not with surgery must be shared with patients, so they can understand the decision process and be aware that some problems/symptoms may not get better with surgery. Most patients believe their hip problem can be cured and expect to be asymptomatic at the end of treatment. This outcome is unlikely for hip pathologies and patients will have a more realistic expectation if they are instructed before surgery about a multilayer diagnosis.

The hip joint is the center of human body movement, and functional hips are required for most activities of daily living. When both hips become symptomatic, life can become particularly challenging. In most hip preservation surgeries, the operated hip will require at least 3 to 6 months of protected activities, and the non-operated hip may become more symptomatic. A THA is usually more foreseeable under the rehabilitation point of view and is a better option for most patients with bilateral hip symptoms and borderline case between preservation and THA. Patient profession is another important factor in borderline cases. Consider the following clinical scenario: a 50-year-old male farmer with symptomatic labral tear and grade 1–2 osteoarthritis with Harris hip score of 60 and Oswestry score of 20%, associated contra-lateral hip and low back pain, need to return to work in weeks after surgery, and average of 2 miles walked daily. Even if imaging studies do not contra-indicate hip preservation surgery, this patient’s profession and clinical scenario indicate that a THA might be a treatment option for him. Conservative treatment or hip arthroscopy could be a more appropriate option to an office worker with the same clinical scenario except for the profession. Per our experience, non-athlete patients with higher physical demands on their job tend to be less satisfied with hip arthroscopy and preservation surgeries. Not only the profession and work are to be considered, but also the physical requirements of leisure and family requirements. Commitment to rehabilitation and family support are factors often overlooked by patients and physicians before making a treatment decision for hip pathologies. Because of the demands involved with recovery processes after hip surgery, the patient may be limited for regular home tasks and requires the support of family. Socioeconomic factors are important to consider when deciding between hip preservation surgery or THA. Hip preservation surgery requires months and sometimes years to reach the maximum improvement, particularly in patients with multilayer hip problems.

The chronicity of hip pain experienced prior can play a role in deciding which treatment route to pursue. Garbuz et al. found that patients who waited more than 6 months before THA had a 50% decrease in the odds of achieving a better-than-expected outcome as measured by the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) when compared to patients with 0–6 months delay [59]. Moreover, each additional month delay after 6 months was associated with 8% additional decrease in odds of achieving a better-than-expected WOMAC score [59]. Similar decreases in clinical outcome scores have been shown with increased preoperative duration of pain in arthroscopic patients. Kunze et al. reported that hip pain from femoroacetabular impingement for 12–24 months in duration preceding surgery was associated with worse postoperative outcomes compared to hip pain with a duration of 3–6 months before surgery [60]. Basques et al. reported similar results: patients with femoroacetabular impingement and more than 2 years of preoperative hip pain have significantly higher 2-year VAS-pain scores, along with significantly lower HOS-ADL, HOS-SS, and mHHS scores after hip arthroscopy [61].

Preoperative opioid use has been associated with less favorable postoperative outcomes after hip preservation surgery and THA. Weick et al. reported that THA patients with >60 days of preoperative opioid use, compared to opioid-naïve patients and patients with <60 days preoperative use, had increased odds of readmission at 30 days postoperatively (OR = 1.46, CI: 1.36–1.57) and needing revision surgery at 1 year (OR = 2.19, CI: 1.84–2.62) [62]. The odds of requiring revision surgery was found to be even greater by the 3-year mark (OR = 1.90, CI: 1.64–2.20) [62]. Zusmanovich et al. reported that patients who regularly used opioids for isolated hip pain within 6 months before hip arthroscopy had higher 1-year postoperative VAS scores compared to opioid-naïve patients (6.1 ± 3.1 vs. 1.5 ± 1.6, respectively) (p < .001) [63]. At 2-year postoperatively, mHHS was significantly lower in the study cohort of opioid users compared to opioid-naïve group (55.4 ± 19.6 vs. 80.4 ± 12.8, respectively) (p < .001) [63]. Nazzal et al. reported that 2501 hip arthroscopy patients who preoperatively were taking >5 oral morphine equivalents had statistically significantly increased odds of prolonged opioid use (i.e. ≥2 opioid prescriptions) in the 6- to 12-month postoperative period (OR, 10.45; p < 0.001) compared to 19,633 patients who took fewer oral morphine equivalents [64]. These patients were also shown to have increased odds of 3-year revision surgery (both hip arthroscopy and total hip arthroplasty: OR = 2.14, p < 0.001 and OR = 2.04, p = 0.001, respectively) [64]. The reversibility of the negative effects of opioid use in hip surgery results has not been defined yet, i.e., does a patient on chronic opioid use benefit from stopping it before a hip surgery? Until further evidence is available, patients might be instructed to work on strategies along with their pain management providers aiming to decrease or stop opioid use before elective hip surgery.

The presence of additional medical conditions may influence the outcome and success of hip reconstruction and preservation procedures. Loth et al. reported that THA patients with ≥1 comorbidity on the Charlson comorbidity index (CCI), pain from other joints, or BMI > 30 kg/m2 did not have significantly different postoperative improvements in pain and joint function when compared to THA patients with no comorbidities [65]. However, patients with comorbidities were still found to have lower general health scores (mean of 39.1 vs. 44.9) as measured by the Short Form-12 (SF-12) (p < .001) [65]. Mannion et al. reported that greater comorbidity was associated with increased odds of a complication and (independently) slightly worse patient-rated outcome 12 months after THA [66]. Fewer studies have investigated the relationship between comorbidities and hip arthroscopy outcomes. Perets et al. reported diabetes mellitus is not significantly associated with worse outcomes in hip arthroscopy cases for treatment of femoroacetabular impingement and labral tears [67]. The psychological status and psychiatric conditions are also to be considered in patients with chronic hip pain. Patients often enter in a pain cycle bolstering the effects of hip pain and limitation in their lives. Sochacki et al. reported that patients with minimal or mild depressive symptoms have better preoperative and postoperative outcomes and are more likely to obtain substantial clinical benefit from surgery than patients with moderate to severe depressive symptoms [68]. Martin et al. reported a high prevalence of patients with symptoms of depression (28%) and severe depression (11%) among 781 patients who underwent hip arthroscopy [69]. The high prevalence of depression in patients with chronic hip pain reinforces the importance of optimal hip function for a healthy mental status. Buller et al. reported the existing diagnosis of depression, dementia, or schizophrenia in THA patients is significantly associated with increased odds of adverse effects after THA (i.e. wound complication, shock, acute renal failure, etc.) [70]. Consultation with a pain psychologist is helpful for patients with chronic hip pain to address the mind effects of chronic pain, and to identify patients whose psychological status may impede improvement after hip surgery.

7. Summary

Evaluation of the anatomy and biomechanics through clinical, functional, and triplanar imaging assessments is essential on decision-making for conservative treatment, hip preservation surgery and THA. The concept of hip layers is very useful for the orthopedic surgeon to identify and organize diagnosis and treatment plan in patients with hip abnormalities, and to relate those to the patient expectations. The effects of abnormal hip biomechanics on the spine-pelvis-CORE need to be considered when treating hip conditions. Hip diseases are treated and rarely cured. The treatment of hip diseases should be approached in a stepwise fashion, starting with education, accommodation, medication, physical therapy, mental rehabilitation, and injections. When conservative measures fail, the surgical treatment decision will be influenced by a comprehensive history and physical examination with triplanar imaging osseous assessment with discussion of patient expectations and commitment. In the future, the influence of hip treatment on hip-spine-pelvic-CORE will play a greater role on decision-making process.