Posterior Mini-Incision With Primary Total Hip Arthroplasty: A Nine to Ten Year Follow Up Study

Direct superior approach for total hip arthroplasty

AIMS

The purpose of this study was to compare the clinical, radiological, and patient-reported outcome measures (PROMs) in the first 100 consecutive patients undergoing total hip arthroplasty (THA) via a direct superior approach (DSA) with a matched group of patients undergoing THA by the same surgeon, using a posterolateral approach (PLA).

METHODS

This was a retrospective single surgeon study comparing the first 100 consecutive DSA THA patients with a matched group of patients using a standard PLA. Case notes were examined for patient demographics, length of hospital stay, operating time, intra- and postoperative complications, pain score, satisfaction score, and Oxford Hip Score (OHS). Leg length discrepancy and component positioning were measured from postoperative plain radiographs.

RESULTS

The DSA patients had a shorter length of hospital stay (mean 2.09 days (SD 1.20) DSA vs 2.74 days (SD 1.17) PLA; p < 0.001) and shorter time to discharge from the inpatient physiotherapy teams (mean 1.44 days (SD 1.17) DSA vs 1.93 days (SD 0.96) PLA; p < 0.001). There were no differences in operating time (p = 0.505), pain levels up to postoperative day 1 (p = 0.106 to p =0.242), OHS (p = 0.594 to p = 0.815), satisfaction levels (p = 0.066 to p = 0.299), stem alignment (p = 0.240), acetabular component inclination (p < 0.001) and anteversion (p < 0.001), or leg length discrepancy (p = 0.134).

CONCLUSION

While the DSA appears safe and was not associated with a significant difference in PROMs, radiological findings, or intraoperative or postoperative complications, a randomized controlled trial with functional outcomes in the postoperative phase is needed to evaluate this surgical approach formally. Cite this article: Bone Joint J 2021;103-B(3):500-506.

Functional Anatomy of the Hip Joint

BACKGROUND

The functional anatomy of the osteoarthritic hip joint in the sagittal plane has not been defined. The purpose of this study was to define the functional anatomy of the hip using clinical and radiographic analyses.

METHODS

320 hips had preoperative standing and sitting lateral spine-pelvis-hip X-rays. Radiographic pelvic measurements were pelvic incidence (PI) and sacral slope (SS), and hip measurements were anteinclination (AI) and pelvic femoral angle (PFA). Pelvic tilt (PT) was calculated as PI-SS. A triangle model was created from the clinical data that illustrates the functional motion of the hip during postural changes from standing to sitting.

RESULTS

Pelvic motion was coordinated with hip motion, even with spinopelvic imbalance and stiffness. Pelvic motion (ΔSS) varied for all 5 types of imbalance, but pelvic motion (ΔSS) and acetabular motion (ΔAI) changed with a 1:1 ratio and inversely with femoral motion (ΔPFA) with a 1:1 ratio. The triangle model showed similar results with ΔSS, ΔPT, and ΔAI changing in a 1:1:1 ratio, and femur motion inversely changing with a 1:1 ratio.

CONCLUSION

The functional anatomy of the hip joint can be visually illustrated using a triangle model. Pelvic angles SS, PT, and AI change in unison, whereas femoral motion (ΔPFA) changes inversely with pelvic motion (ΔSS) in a 1:1 ratio. This coordinated mobility explains the limitations of the Lewinnek safe zone, which include only the acetabulum.

The Impact of Spinopelvic Mobility on Arthroplasty: Implications for Hip and Spine Surgeons

Spinopelvic mobility represents the complex interaction of hip, pelvis, and spine. Understanding this interaction is relevant for both arthroplasty and spine surgeons, as a predicted increasing number of patients will suffer from hip and spinal pathologies simultaneously. We conducted a comprehensive literature review, defined the nomenclature, summarized the various classifications of spinopelvic mobility, and outlined the corresponding treatment algorithms. In addition, we developed a step-by-step workup for spinopelvic mobility and total hip arthroplasty (THA). Normal spinopelvic mobility changes from standing to sitting; the hip flexes, and the posterior pelvic tilt increases with a concomitant increase in acetabular anteversion and decreasing lumbar lordosis. Most classifications are based on a division of spinopelvic mobility based on ΔSS (sacral slope) into stiff, normal, and hypermobile, and a categorization of the sagittal spinal balance regarding pelvic incidence (PI) and lumbar lordosis (LL) mismatch (PI–LL = ± 10° balanced versus PI–LL > 10° unbalanced) and corresponding adjustment of the acetabular component implantation. When performing THA, patients with suspected pathologic spinopelvic mobility should be identified by medical history and examination, and a radiological evaluation (a.p. pelvis standing and lateral femur to L1 or C7 (if EOS (EOS imaging, Paris, France) is available), respectively, for standing and sitting radiographs) of spinopelvic parameters should be conducted in order to classify the patient and determine the appropriate treatment strategy. Spine surgeons, before planned spinal fusion in the presence of osteoarthritis of the hip, should consider a hip flexion contracture and inform the patient of an increased risk of complications with existing or planned THA.

Piriformis-Sparing Minimally Invasive Versus the Standard Posterior Approach for Total Hip Arthroplasty: A 10-Year Follow-Up of a Randomized Control Trial

BACKGROUND

Despite the popularity of minimally invasive approaches in total hip arthroplasty, studies regarding their impact on soft tissues and long-term benefits are lacking. This study aims to compare the 10-year functional outcome of the piriformis-sparing minimally invasive approach to the standard posterior approach for total hip arthroplasty surgery.

METHODS

Hundred patients were randomized, 48 patients to the piriformis-sparing approach and 52 to the standard approach. Primary outcomes were hip function and piriformis muscle volume and grade on magnetic resonance imaging. Secondary outcomes were pain, satisfaction score, and complications. Evaluators were blinded to allocation. Participants were followed up to 10 years.

RESULTS

Ten years following surgery, both groups reported excellent pain relief, improved hip function, and high satisfaction. The significant differences were improvement in piriformis muscle volume (P = .001) and muscle grade (P = .007) in the piriformis-sparing group compared to the standard group. There were no significant differences in all other outcomes.

CONCLUSION

Aside from being less injurious to the piriformis muscle, the piriformis-sparing approach offered the same long-term functional benefits as the standard posterior approach at 10 years.

Late Dislocation Following Total Hip Arthroplasty: Spinopelvic Imbalance as a Causative Factor

BACKGROUND

Late dislocations after total hip arthroplasty (THA) are challenging for the hip surgeon because the cause is often not evident and recurrence is common. Recently, decreased spinopelvic motion has been implicated as a cause of dislocation. The purpose of this study was to assess the mechanical causes of late dislocation, including the influence of spinopelvic motion.

METHODS

Twenty consecutive patients were studied to identify the cause of their late dislocation. Cup inclination and anteversion were measured on standard pelvic radiographs. Lateral standing and sitting spine-pelvis-hip radiographs were used to measure pelvic motion, femoral mobility, and sagittal cup position by assessing sacral slope, pelvic-femoral angle, and cup ante-inclination. Spinopelvic motion was defined as the difference between the standing and sitting sacral slopes (Δsacral slope). A new measurement, the combined sagittal index, which measures the sagittal acetabular and femoral positions, was used to assess the functional motion of the hip joint and risk of impingement.

RESULTS

There were 9 anterior dislocations (45%) and 11 posterior dislocations (55%) at a mean of 8.3 years after a primary THA. Eight of the 9 patients with an anterior dislocation had spinopelvic abnormalities such as fixed posterior pelvic tilt when standing, increased standing femoral extension, and an increased standing combined sagittal index. Ten of the 11 patients with a posterior dislocation had abnormal spinopelvic measurements such as decreased spinopelvic motion (average Δsacral slope [and standard error] = 9.0° ± 2.4°), increased femoral flexion, and a decreased sitting combined sagittal index. For every 1° decrease in spinopelvic motion, there was an associated 0.9° increase in femoral motion and, in some patients, this resulted in osseous impingement and dislocation.

CONCLUSIONS

Patients with a late dislocation have abnormal spinopelvic motion that precipitates the dislocation, especially when combined with cup malposition or soft-tissue abnormalities. Spinopelvic stiffness is associated with increased age and increased femoral motion, which may lead to impingement and dislocation. Lateral spine-pelvis-hip radiographs may predict the risk and direction of dislocation.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Opioid Crisis and the Orthopedic Surgeon

Opioid use and abuse has become a national crisis in the United States. Many opioid abusers become addicted through an initial course of legal, physician-prescribed medications. Consequently, there has been increased pressure on medical care providers to be better stewards of these medications. In orthopedic surgery and total joint arthroplasty, pain control after surgery is critical for restoring mobility and maintaining patient satisfaction in the early postoperative period. Before the opioid misuse epidemic, orthopedic surgeons were frequently influenced to "treat pain with pain medications." Long-acting opioids, such as OxyContin were used commonly. In the past decade, there has been a paradigm shift in favor of multimodal pain control with limited opioid use. This review will discuss 4 major topics. First, we will describe the pressures on orthopedic surgeons to prescribe narcotic pain medications. We will then discuss the major and minor complications and side effects associated with these prescriptions. Second, we will review how these factors motivated the development of alternative pain management strategies and a multimodal approach. Third, we will look at perioperative interventions that can reduce postoperative opioid consumption, including wound injections and peripheral nerve blocks, which have shown superb clinical results. Finally, we will recommend an evidence-based program that avoids parenteral narcotics and facilitates rapid discharge home without readmissions for pain-related complaints.

Minimal Incision Total Hip Arthroplasty: A Concise Follow-up Report on Functional and Radiographic Outcomes at 10 Years

In 2005, we conducted a prospective randomized controlled trial that demonstrated that, compared with a standard incision, a minimal incision technique did not improve early outcomes of total hip arthroplasty (THA). There was concern that reduced exposure could compromise long-term outcome. For the current study, all surviving participants were invited to return for 10-year radiographic and clinical evaluation. Outcome scores were available for 152 patients (69.4%) from the original cohort, and radiographs were available for 126 (57.5%). The median duration of follow-up was 124 months. We did not find significant differences in functional status or radiographic outcome between the minimal and standard incision groups at 10 years. The 10-year implant survival rate was 99.1% (95% confidence interval [CI] = 97.3% to 100%) in the standard incision group and 97.9% (95% CI = 95.1% to 100%) in the minimal incision group (p = 0.57). We concluded that minimal incision THA performed by a high-volume surgeon does not compromise long-term results but offers no benefit over a standard incision.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Spinopelvic mobility and acetabular component position for total hip arthroplasty

Aims

Posterior tilt of the pelvis with sitting provides biological acetabular opening. Our goal was to study the post-operative interaction of skeletal mobility and sagittal acetabular component position.

Materials and Methods

This was a radiographic study of 160 hips (151 patients) who prospectively had lateral spinopelvic hip radiographs for skeletal and implant measurements. Intra-operative acetabular component position was determined according to the pre-operative spinal mobility. Sagittal implant measurements of ante-inclination and sacral acetabular angle were used as surrogate measurements for the risk of impingement, and intra-operative acetabular component angles were compared with these.

Results

Post-operatively, ante-inclination and sacral acetabular angles were within normal range in 133 hips (83.1%). A total of seven hips (4.4%) had pathological imbalance and were biologically or surgically fused hips. In all, 23 of 24 hips had pre-operative dangerous spinal imbalance corrected.

Conclusions

In all, 145 of 160 hips (90%) were considered safe from impingement. Patients with highest risk are those with biological or surgical spinal fusion; patients with dangerous spinal imbalance can be safe with correct acetabular component position. The clinical relevance of the study is that it correlates acetabular component position to spinal pelvic mobility which provides guidelines for total hip arthroplasty. Cite this article: Bone Joint J 2017;99-B(1 Supple A):37–45.