Prevalence of Lumbosacral Transitional Vertebrae in Patients With Symptomatic Femoroacetabular Impingement Requiring Hip Arthroscopy

Editorial Commentary: Spine Pathology May Improve or Worsen Outcomes After Hip Arthroscopy: Patient Evaluation and Indications Are Critical

Compared with total hip arthroplasty, hip arthroscopy is a relatively new procedure, and as such, hip-spine syndrome in young adults is an emerging topic of research. In the past decade, our understanding of spinopelvic alignment has improved the stability and survivorship of hip replacements in patients with prior lumbar fusions. Obviously, the hip affects the spine and the spine affects the hip. In terms of hip arthroscopy, just as older patients and patients with cartilage damage have inferior outcomes, patients with spine pathology are at risk for postoperative worsening spinal symptoms, including sciatica. In addition, back and radicular pain may limit postoperative hip rehabilitation. Yet other patients show resolution of back symptoms after hip arthroscopy. Today, surgeons indicating hip arthroscopy must first investigate patient sagittal balance, which includes pelvis tilt, pelvic incidence, and sacral slope. When properly indicated, hip-spine pain patients show greater percentage improvement with no increased failure risk compared with patients with isolated FAIS. Exceptions include patients with concomitant lumbar stenosis or lumbar fusion. Rate of revision hip arthroscopy and conversion to total hip replacement is 2-fold compared with controls if patients had prior 1-2 level fusion and 3-fold if 3 or more levels are fused. Our understanding of hip-spine patients with regard to arthroscopy outcomes continues to develop. In addition to a comprehensive spine exam, the patient's spine surgical history and current spine symptoms must be investigated to predict the efficacy of hip arthroscopy. If patients have both hip and spine symptoms, a diagnostic hip injection to determine the prime pain generator is essential. If the hip is the source of pain, patients should be counseled that back symptoms will likely improve after hip arthroscopy but not in all cases. EOS imaging to measure sagittal balance may allow the surgeon to predict if impingement measurements on hip radiographs may be underestimated in the setting of a stiff spine. If the patient has multiple risk factors for poor outcomes such as advancing age, articular cartilage damage, borderline dysplasia, or hypermobility, on top of a history of multilevel lumbar fusion or spinal deformity, hip arthroscopy may not be ideal, and hip arthroplasty should be considered. Clearly, the spine may not be ignored in patients with femoroacetabular impingement.

Over 50% of Studies Report Low-Back Pain Is Associated With Worse Outcomes After Hip Arthroscopy When Compared With a Control Group: A Systematic Review

PURPOSE

To review outcomes of patients with low-back pathology undergoing primary hip arthroscopy for the treatment of femoroacetabular impingement (FAI) syndrome.

METHODS

The PubMed, Cochrane Trials, and Scopus databases were queried in June 2022 to conduct this systematic review using the following terms: ("hip" OR "femoroacetabular impingement") AND ("arthroscopy" OR "arthroscopic") AND ("spine" OR "lumbar" OR "sacral" OR "hip-spine" OR "back") AND ("outcomes"). Articles were included if they reported on patient-reported outcomes (PROs) and/or clinical benefit of patients undergoing hip arthroscopy with concomitant low-back pathology. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) criteria. Case reports, opinion articles, review articles, and technique articles were excluded from this study. Forest plots were created to analyze preoperative and postoperative outcomes among patients with low-back pathology.

RESULTS

Fourteen studies were included in the review. There were 750 hips with low-back pathology and FAI (hip-spine syndrome) and 1,800 hips with only FAI (no hip-spine syndrome). All 14 studies reported PROs. In 4 studies in the group with hip-spine syndrome and 8 studies in the group with FAI without low-back pathology, the respective cohorts were reported to achieve the minimal clinically important difference in at least 1 PRO at a rate of 80%. Eight studies reported that patients with low-back pathology were associated with inferior outcomes or clinical benefit compared with patients without low-back pathology.

CONCLUSIONS

Patients undergoing primary hip arthroscopy with concomitant low-back pathology can expect favorable outcomes, but outcomes are superior in patients undergoing hip arthroscopy for FAI alone compared with FAI with concomitant low-back pathology.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II to Level IV studies.

Editorial Commentary: Restrictions in Spinal Motion Result in Lower Outcome Scores After Hip Arthroscopy

The critical consideration in determining the efficacy of hip surgery is patient-reported outcomes, specifically the achievement of the clinical threshold. Several studies examined the achievement of the clinical threshold following hip arthroscopy (HA) in the presence of coexisting lumbar spine disease. The condition related to the spine receiving a lot of focus in recent research is the lumbosacral transitional vertebrae (LSTV). However, this condition could be just the tip of the iceberg. To forecast the outcomes of HA, it is far more important to comprehend spinopelvic motion. Since higher-grade LSTV is associated with less lumbar spine flexibility and reduces the ability to antevert acetabulum, it is possible that LSTV severity or grading could be one of the indicators of less effective operation "especially in "hip users"' (hip users are defined as patents who are more dependent on on hip motion than spinal motion). In light of this, lower-grade LSTV ought to have a less significant impact on surgical outcomes than higher-grade LSTV.

The Outcome of Hip Arthroscopy in the Setting of Lumbar Spine Disease Is Beneficial, Yet Limited: A Systematic Review of Existing Evidence

PURPOSE

To compare hip arthroscopy outcomes in femoroacetabular impingement (FAI) patients with concurrent symptomatic lumbar spine disease to the outcomes of arthroscopic FAI patients without spine disease.

METHODS

A systematic review was performed according to PRISMA guidelines via PubMed, Cochrane, Embase, and Google Scholar databases. Studies were valid for inclusion if they had an average follow-up ≥12 months and compared patient-reported outcome measures (PROMs) in hip arthroscopy patients with and without concurrent spinal disease. Data collected included study characteristics, patient demographics, follow-up intervals, surgical indications, spinal pathology, PROMs, and reoperation rates.

RESULTS

Twelve studies were included in this systematic review. 3,107 patients who underwent hip arthroscopy were evaluated: 1,056 with coexisting lumbar spine disease (spine cohort) and 2,051 control subjects without spine disease (control cohort). The average follow-up period was 24 months. Across included studies, there were 35 instances wherein postoperative PROM scores reported by each cohort were compared. In all 35 instances, the spine cohort reported inferior postoperative PROM scores with the difference being significant (P < .05) on 23 PROMs. Collectively, 23 cases were available contrasting the proportion of each cohort to achieve the minimal clinically important difference (MCID). In 22 (95.65%) of these cases, the spine cohort achieved the MCID at a lower rate than the control cohort. There were 14 PROMs, wherein intragroup analyses were reported that compared the preoperative and postoperative score reported by the spine cohort. On all 14 PROMs, the spine cohort reported significant (P < .05) improvement after arthroscopic intervention.

CONCLUSION

FAI patients with coexisting lumbar spine pathology experience significant improvement from baseline state after arthroscopic intervention. However, the postoperative outcomes reported are inferior, and the improvement from arthroscopy was limited when compared to surgical control subjects with FAI and normal spinal anatomy.

LEVEL OF EVIDENCE

Level IV: systematic review of Level II, III, and IV studies.

Patients With Low-Grade Lumbosacral Transitional Vertebrae Demonstrate No Difference in Achievement of Clinical Thresholds After Hip Arthroscopy for Femoroacetabular Impingement Syndrome

PURPOSE

To compare clinical outcomes at 2 years following primary hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) between patients with and without low-grade lumbosacral transitional vertebra (LSTV).

METHODS

We performed a retrospective matched-cohort analysis of patients who underwent primary HA for FAIS from 2011 to 2018 with minimum 2-year follow-up. LSTV was graded on preoperative radiographs using the Castellvi classification. Patients with grades I and II LSTV were matched 1:1 with controls on age, sex, and body mass index. Radiographic markers of FAIS morphology were measured. Pre- to postoperative improvement in the modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS) as well as 2-year achievement rates for the minimum clinically-important difference, substantial clinical benefit, and patient acceptable symptom state were compared between patients with versus without LSTV. The Wilcoxon signed-rank test was used for intergroup mean comparisons and the Cochran-Mantel-Haenszel test for categorical variables.

RESULTS

In total, 58 patients with LSTV were matched to 58 controls. Among LSTV patients, 48 were Castellvi type 1 (82.8%) and 32 (55.2%) had bilateral findings. No significant differences were found between groups with respect to radiographic markers of FAIS, including alpha angle (P = .88), lateral center edge angle (P = .42), or crossover sign (P = .71). Although patients with LSTV had greater improvement in NAHS at 2-year follow-up compared with control patients (P = .04), there were no significant differences in modified Harris Hip Score improvement (P = .31) or achievement of the minimum clinically-important difference (P = .73), substantial clinical benefit (P = .61), or patient acceptable symptom state (P = .16).

CONCLUSIONS

Patients with low-grade LSTV had greater 2-year improvement in NAHS than controls, whereas no significant differences were observed in achievement of clinical thresholds at 2-year follow-up. There were no differences between groups with respect to any measured radiographic markers of FAIS morphology. Importantly, the findings of this study are underpowered and should be viewed with caution in the greater context of the LSTV literature.

LEVEL OF EVIDENCE

III; retrospective comparative study.

Prevalence of Lumbosacral Transitional Vertebral Anomalies Among Healthy Volunteers and Patients with Hip Pathology: Association with Spinopelvic Characteristics

A lumbosacral transitional vertebra (LSTV) has been reported to be prevalent among patients with hip dysplasia. The aims of this study were to determine the (1) prevalence of an LSTV in young patients presenting with hip pain and a group of asymptomatic volunteers, (2) effect of an LSTV on spinopelvic characteristics, and (3) presence of low back pain among patients with an LSTV.

Methods

This cross-sectional study included 102 patients with hip pathology and 51 asymptomatic volunteers (mean age, 33.9 ± 7.3 years; mean body mass index, 26.0 ± 5.0 kg/m2; 57.5% female). Participants underwent radiographic assessment of the lumbar spine and pelvis in standing and deep-seated positions. LSTV occurrence was classified according to the Castellvi system. Spinopelvic characteristics included lumbar lordosis (including segmental lumbar angles), pelvic tilt, and hip flexion (pelvic-femoral angle). Differences between standing and deep-seated values were calculated. Low back pain was assessed using the Oswestry Disability Index.

Results

The prevalence of LSTV type ≥II was 8.5%, with no difference between patients and volunteers (p = 0.386). Individuals with an LSTV had a greater standing L1-L5 angle (mean, 51.6° ± 11.7° versus 38.9° ± 9.3°; p < 0.001). The overall spinal flexion (change in L1-S1 angle between the standing and deep-seated positions) in individuals with an LSTV was similar to that in individuals without an LSTV; restricted L5-S1 mobility was compensated for at L1-L2 (10.2° ± 5.8° in those with versus 8.4° ± 4.1° in those without an LSTV; p = 0.070). No significant difference in the presence of low back pain was found (p = 0.250).

Conclusions

An LSTV was found in 8.5% of young adults, with no difference between patients with hip pathology and controls. Individuals with an LSTV have greater standing lumbar lordosis, with altered mechanics at the cephalad adjacent level, which may predispose these individuals to degenerative changes at this level.

Level of Evidence

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Open and arthroscopic management of femoroacetabular impingement: a review of current concepts

Femoroacetabular impingement (FAI) is a common femoral and/or acetabular abnormality that can cause progressive damage to the hip and osteoarthritis. FAI can be the result of femoral head/neck overgrowth, acetabular overgrowth or both femoral and acetabular abnormalities, resulting in a loss of native hip biomechanics and pain upon hip flexion and rotation. Radiographic evidence can include loss of sphericity of the femoral neck (cam impingement) and/or acetabular retroversion with focal or global overcoverage (pincer impingement). Operative intervention is indicated in symptomatic patients after failed conservative management with radiographic evidence of impingement and minimal arthritic changes of the hip, with the goal of restoring normal hip biomechanics and reducing pain. This is done by correcting the femoral head-neck relationship to the acetabulum through femoral and/or acetabular osteoplasty and treatment of concomitant hip pathology. In pincer impingement cases with small lunate surfaces, reverse periacetabular osteotomy is indicated as acetabular osteoplasty can decrease an already small articular surface. While surgical dislocation is regarded as the traditional gold standard, hip arthroscopy has become widely utilized in recent years. Studies comparing both open surgery and arthroscopy have shown comparable long-term pain reduction and improvements in clinical measures of hip function, as well as similar conversion rates to total hip arthroplasty. However, arthroscopy has trended toward earlier improvement, quicker recovery and faster return to sports. The purpose of this study was to review the recent literature on open and arthroscopic management of FAI.

Hip-Spine Syndrome in the Nonarthritic Patient

Hip-spine syndrome refers to concurrent hip and spine pathology with overlapping symptoms. Most of the literature has studied it in relation to total hip arthroplasty literature and has been shown to increase dislocation risk. Lumbar spine and pelvic mobility have been studied less frequently in relation to nonarthritic pathologic hip states. Understanding the biomechanical relationship between the lumbar spine, pelvis, and hip can help elucidate how hip-spine syndrome affects the nonarthritic hip and how it impacts outcomes of hip arthroscopy. Changes in lumbar spine motion may be the reason certain predisposed patients develop symptomatic femoroacetabular impingement (FAI) or ischiofemoral impingement. Some athletes may be "hip users" with a low pelvic incidence, making them more reliant on hip motion due to less-intrinsic lumbopelvic motion. When these patients have FAI morphology, their increased reliance on hip motion makes them prone to experiencing femoroacetabular contact and concurrent symptoms. Other athletes may be "spine users," with larger pelvic incidence and more baseline lumbopelvic motion, making them less reliant on hip motion and therefore less prone to experiencing hip impingement even with hip FAI morphology. Hip-spine syndrome also appears to have an impact on patient selection, role of nonoperative treatment, and hip arthroscopy surgical outcomes. Identifying patients with concurrent pathology may allow surgeons to recommend targeted physical therapy or counsel patients better on their expectations after surgery.

Hip Spine Syndrome Negatively Impacts Arthroscopic Outcomes in the Management of Femoroacetabular Impingement Syndrome: A Systematic Review

To determine whether the presence of spine pathology affects clinical outcomes after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) in the setting of hip-spine syndrome (HSS) METHODS: A systematic review of PubMed and Cochrane was conducted. Primary research articles evaluating patient-reported outcomes (PRO) after hip arthroscopy for FAIS in the presence of concomitant spine pathology were considered RESULTS: Literature review identified 12 studies meeting criteria. In 2109 FAIS patients undergoing hip arthroscopy, 591 had concomitant spine pathology. Baseline PROs in the hip-spine (modified Harris Hip Score [mHHS]: 39.8-65.29 vs 56.9-78.8, 8 studies; non-arthritic hip score [NAHS]: 42.2-51.5 vs 68.2-75.2, 4 studies; hip outcome score-activities of daily living [HOS-ADL]: 45.9-71.1 vs 49.3-89.51, 9 studies; hip outcome score-Sport (HOS-Sport): 22.8-49.6 vs 50.6-73.1, 3 studies; international hip outcome tool-33 [iHOT-12]: 38.0 vs 66.0, 1 study; visual analog scale [VAS] Pain: 6.43-6.56 vs 1.18-3.60, 3 studies; VAS Satisfaction: 7.18-7.46 range at follow-up, 2 studies) and control (mHHS: 39.3-64.9 vs 70.2-92.6, 6 studies; NAHS: 42.8-54.2 vs 74.0-87.1, 4 studies; HOS-ADL: 59.0-76.4 vs 75.4-97.1, 4 studies; HOS-Sport: 38.1-55.1 vs 60.9-93.9, 3 studies; iHOT-12: 43.4 vs 89.8, 1 study; VAS Pain: 6.18-6.22 vs 1.82-3.44, 2 studies; VAS Satisfaction: 7.74-8.22 range at follow up, 2 studies). Minimal clinically important difference threshold rates achieved in the hip-spine (44.1-86.7, 4 studies) cohorts were significantly lower than control (79.4-88.2%; 4 studies) cohorts in 3 studies. Patient-acceptable symptomatic state threshold rates achieved in the hip-spine (42-63.5, 3 studies) cohorts were significantly lower than control (58.8-81.0, 3 studies) in 1 study. There was no statistical difference in complication and reoperation rates between cohorts CONCLUSION: FAIS patients with concomitant HSS have improved but inferior outcomes after hip arthroscopy compared to patients without HSS LEVEL OF EVIDENCE: IV, systematic review.

Limited lumbopelvic mobility does not influence short-term outcomes after primary hip arthroscopy: a propensity-matched controlled study

There is a paucity of literature investigating the effect of lumbopelvic mobility on patient-reported outcome scores (PROs) after primary hip arthroscopy. The purpose of this study was (i) to report minimum 1-year PROs in patients with limited lumbopelvic mobility (LM) who underwent primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS) and (ii) to compare clinical results with a propensity-matched control group of patients with normal lumbopelvic mobility (NM). Data were reviewed for surgeries performed between November 2019 and March 2020. Patients were considered eligible if they received a primary hip arthroscopy for FAIS in the setting of LM (seated to standing change in sacral slope ≤ 10°). LM patients were propensity-matched to a control group of patients with normal lumbopelvic motion (seated to standing change in sacral slope > 10°) for comparison. A total of 17 LM and 34 propensity-matched NM patients were included in the study. LM patients showed significant improvement in all outcome measures and achieved the minimum clinically important difference (MCID) and patient acceptable symptomatic state (PASS) at high rates for modified Harris Hip Score (MCID: 94% and PASS: 82%) and International Hip Outcome Tool-12 (iHOT-12; MCID: 94% and iHOT-12: 76%). When LM patients were compared to a propensity-matched control group of NM patients, they demonstrated similar postoperative PROs and rates of achieving MCID/PASS. LM patients who undergo primary hip arthroscopy may expect favorable short-term PROs at minimum 1-year follow-up. These results were comparable to a control group of NM patients.

Editorial Commentary: Lumbosacral Anatomy and Mechanics Influence Femoroacetabular Impingement Syndrome and Surgical Outcomes: The Hip Bone Is Connected to the Back Bone

The hip joint in general and femoroacetabular impingement (FAI) in particular do not exist in a vacuum. Impingement kinematics are very closely tied to the relationship between spinopelvic motion and posture, and that of the hip joint itself. While the relationship of lumbar degenerative disease, fusion, and sagittal balance to hip arthroplasty has been well studied, there is a paucity of data on the analogous relationship of the stiff spine with hip arthroscopy and FAI. While further studies are critical in advancing our understanding of this relationship in this unique population, surgeons still must consider the relationship of lumbosacral motion and posture, including the anatomic variant of lumbosacral transitional vertebrae, when evaluating and treating patients with FAI.