Biomechanical Comparison of Capsular Repair, Capsular Shift, and Capsular Plication for Hip Capsular Closure: Is a Single Repair Technique Best for All?

Imaging evaluation of hip capsule disorders: a comprehensive review

The hip capsule and capsular ligaments play crucial roles in providing hip stability and mobility. Their role in hip pathologies is being increasingly recognized, underscoring the need for thorough imaging evaluation, which is better performed through MRI-arthrography. Various diseases affect the hip capsule directly or indirectly. Improper mechanical loading, as seen in conditions such as femoroacetabular impingement or chondrolabral pathology, can induce capsule thickening, whereas thinning and laxity of the capsule are characteristics of microinstability. Inflammatory conditions, including adhesive capsulitis of the hip, crystal deposition disease, polymyalgia rheumatica, and infections, also lead to capsular changes. Traumatic events, particularly posterior hip dislocations, cause capsule ligament disruption and may lead to hip macroinstability. Friction syndromes can lead to capsular edema due to impingement of the adjacent capsule. Hip arthroscopy can result in various postoperative findings ranging from fibrotic adhesions to focal or extensive capsule discontinuation. Although the significance of hip capsule thickness and morphology in the pathogenesis of hip diseases remains unclear, radiologists must recognize capsule alterations on imaging evaluation. These insights can aid clinicians in accurately diagnosing and effectively managing patients with hip conditions.

The Contribution of Soft Tissue and Bony Stabilizers to the Hip Suction Seal: A Systematic Review of Biomechanical Studies

BACKGROUND

Previous biomechanical studies have identified capsular closure, labral repair or reconstruction, and osteochondroplasty as important surgical interventions to improve hip stability.

PURPOSE

To investigate the outcome metrics used to quantify hip stability and assess and measure the relative contributions of the labrum, capsule, and bone to hip stability through a quantitative analysis.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

PubMed and Embase databases were searched using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included studies evaluated cadaveric hip biomechanics related to capsular, labral, and bony management during hip arthroscopy. Studies were assessed for distraction force and distance, fluid measures, and contact forces used to quantify the suction seal. Exclusion criteria included open surgery, arthroplasty, reorientation osteotomy, or traumatic dislocation.

RESULTS

A total of 33 biomechanical studies comprising 322 hips that evaluated 1 or more of the following were included: distraction force or distance (24 studies), fluid measures (10 studies), and contact forces (6 studies). Compared with a capsulotomy or capsulectomy, capsular repair or reconstruction demonstrated greater resistance to distraction (standardized mean difference [SMD], 1.13; 95% CI, 0.46-1.80; P = .0009). Compared with a labral tear, a labral repair or reconstruction demonstrated less resistance to distraction (SMD, -0.67; 95% CI, -1.25 to -0.09; P = .02). Compared with a labral debridement, repair or reconstruction demonstrated greater resistance to distraction (SMD, 1.74; 95% CI, 1.23 to 2.26; P < .00001). No quantitative analysis was feasible from studies evaluating the effect of osseous resection due to the heterogeneity in methodology and outcome metrics assessed.

CONCLUSION

Most biomechanical evidence supports capsulotomy repair or reconstruction to improve hip distractive stability at the end of hip arthroscopic surgery. While the repair of a torn labrum does not improve distractive resistance, it is superior to labral debridement in most biomechanical studies.

Editorial Commentary: Protected Physical Therapy and Rehabilitation Is Essential After Hip Capsule and Labral Repair

Hip arthroscopy is an effective procedure with rapidly improving techniques and implants. Routine labral and capsular repair are broadly agreed upon as standard of care in most cases, which is now supported by long-term outcome studies. A crucial component of patient postoperative success is physical therapy. While accelerated programs are appealing, biomechanical studies have consistently demonstrated decreased stability at time zero after hip arthroscopy, particularly labral repairs. Therefore, although we want to help our patients get back to their lives as soon as possible, it remains our responsibility to protect their hip in the early postoperative period. If, in ideal laboratory conditions, we cannot restore stability to an intact state, then we must presuppose that the suction seal improves as the capsule, and more importantly, the labrum, heals after surgical manipulation. This means we are not able to rely solely on the strength of our repair, and there is a distinct period where the repaired hip is particularly vulnerable. Most hip arthroscopy protocols use a protective period, ranging from 4 to 8 weeks, during which there is an emphasis on passive range of motion only, with a strict moratorium on "pushing beyond pain."

Capsular Repair Versus No Repair After Hip Arthroscopy in Patients Without Dysplasia or Generalized Ligamentous Laxity: A Systematic Review and Meta-analysis

Background

Many recent studies have shown that patients who undergo capsular repair after hip arthroscopy achieve superior clinical outcomes compared with those who do not. However, patients with dysplasia or generalized ligamentous laxity (GLL) were not excluded from most of these studies, which may have affected the outcomes.

Purpose

To determine whether capsular repair influences the outcomes of hip arthroscopy for patients without dysplasia or GLL.

Study Design

Systematic review; Level of evidence, 1.

Methods

Under the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, randomized controlled trials comparing the outcomes of capsulotomy with versus without repair were included, but studies that included patients with dysplasia or GLL were excluded. The study outcomes were patient-reported outcome measures (PROMs) at 6 months and 2 years postoperatively-including the modified Harris Hip Score (mHHS), Hip Outcome Score-Activities of Daily Living (HOS-ADL), and Hip Outcome Score-Sport-Specific Subscale (HOS-SSS)- and were compared between the repair and no-repair groups. A narrative analysis and meta-analysis were performed to integrate and compare the results of the 2 groups. In the meta-analysis of the outcome measures, studies with significant differences in the preoperative scores between the repair and no-repair groups were excluded because previous studies have shown that these can affect the outcomes.

Results

A total of 761 studies were initially identified, of which 3 were included. Of the 322 included patients, 136 underwent capsular repair, and 186 underwent capsulotomy with no repair. The meta-analysis showed that capsular repair was associated with significantly higher postoperative PROMs: the mHHS at 2 years (P = .03), the HOS-ADL at 6 months (P = .02) and 2 years (P < .0001), and the HOS-SSS at 6 months (P = .02) and 2 years (P = .001).

Conclusion

Capsular repair after hip arthroscopy was associated with superior clinical outcomes when compared with no capsular repair in patients without dysplasia or GLL.

Hip Labral and Capsular Repair Are Unable to Restore Distractive Stability in a Biomechanical Model

PURPOSE

To evaluate the change in hip distractive stability after a capsulotomy, labral tear, and simultaneous repair of both the capsule and the labrum in a biomechanical model.

METHODS

Ten fresh-frozen human cadaveric hips were analyzed using a materials testing system to measure the distractive force and distance required to disrupt the hip suction seal under the following conditions: (1) native intact capsule and labrum, (2) 2- or 4-cm interportal capsulotomy (IPC), (3) labral tear, (4) T extension, (5) labral repair, (6) T extension repair, and (7) IPC repair. Each specimen was retested at 0° of flexion, 45° of flexion, and 45° of flexion with 15° of internal rotation.

RESULTS

A significantly higher distractive force was required to rupture the suction seal in the intact condition compared with IPC (P = .012; 95% confidence interval [CI], 4.9-42.4); IPC and labral tear (P = .002; 95% CI, 11.3-49.4); IPC, labral tear, and T extension (P = .001; 95% CI, 13.9-51.5); IPC, labral repair, and T extension (P < .001; 95% CI, 20.8-49.7); IPC, labral repair, and T extension repair (P = .002; 95% CI, 12.5-52.4); and IPC repair, labral repair, and T extension repair (P = .01; 95% CI, 5.8-46.1). The IPC condition required a higher distractive force in isolation than when combined with a labral tear (P = .14; 95% CI, 1.2-12.0), T extension (P = .005; 95% CI, 2.8-15.3), or labral repair (P = .002; 95% CI, 4.4-18.8).

CONCLUSIONS

The distractive resistance of an intact hip capsule and labrum was not restored once the soft tissues were violated, despite labral repair with a loop technique and capsular repair with interrupted figure-of-8 sutures.

CLINICAL RELEVANCE

Time-zero complete capsular repair with concomitant labral repair may not be adequate to restore distractive hip stability after hip arthroscopy, reinforcing the use of postoperative precautions in the early postoperative period.

Capsular Management at the Time of Hip Arthroscopy for Femoroacetabular Impingement Syndrome Varies With Geography and Surgeon Subspecialty Training: A Cross-Sectional, Multinational Surgeon Survey

PURPOSE

To perform a multinational survey and identify patterns in capsular management at the time of hip arthroscopy.

METHODS

An anonymous, nonvalidated survey was distributed by the American Orthopaedic Society for Sports Medicine; Arthroscopy Association of North America; European Society of Sports Traumatology, Knee Surgery & Arthroscopy; International Society for Hip Arthroscopy; and Turkish Society of Sports Traumatology, Arthroscopy, and Knee Surgery. The questions were broken down into 6 categories: demographic characteristics, capsulotomy preference, traction stitches, capsular closure, postoperative rehabilitation, and postoperative complications.

RESULTS

The survey was completed by 157 surgeons. Surgeons who performed half or full T-type capsulotomies had 2.4 higher odds of using traction sutures for managing both the peripheral and central compartments during hip arthroscopy for femoroacetabular impingement (P = .024). Surgeons who believed that there was sufficient literature regarding the importance of hip capsular closure had 1.9 higher odds of routinely performing complete closure of the capsule (P = .044). Additionally, surgeons who practiced in the United States had 8.1 higher odds of routinely closing the capsule relative to international surgeons (P < .001). Moreover, surgeons who received hip arthroscopy training in residency or fellowship had 2.4 higher odds of closing the capsule completely compared with surgeons who did not have exposure to hip arthroscopy during their training (P = .009).

CONCLUSIONS

Geographic and surgeon-related variables correlate with capsular management preferences during hip arthroscopy. Surgeons who perform half or full T-capsulotomies more often use traction stitches for managing both the peripheral and central compartments. Surgeons performing routine capsular closure are more likely to believe that sufficient evidence is available to support the practice, with surgeons in the United States being more likely to perform routine capsular closure in comparison to their international colleagues.

CLINICAL RELEVANCE

As the field of hip preservation continues to evolve, capsular management will likely continue to play an important role in access, instrumentation, and postoperative outcomes.

Early Postoperative Activities of Daily Living Do Not Adversely Affect Joint Torques or Translation Regardless of Capsular Condition: A Cadaveric Study

PURPOSE

To evaluate the impact of capsular management on joint constraint and femoral head translations during simulated activities of daily living (ADL).

METHODS

Using 6 (n = 6) cadaveric hip specimens, the effect of capsulotomies and repair was then evaluated during simulated ADL. Joint forces and rotational kinematics associated with gait and sitting, adopted from telemeterized implant studies, were applied to the hip using a 6-degrees of freedom (DOF) joint motion simulator. Testing occurred after creation of portals, interportal capsulotomy (IPC), IPC repair, T-capsulotomy (T-Cap), partial T-Cap repair, and full T-Cap repair. The anterior-posterior (AP), medial-lateral (ML), and axial compression DOFs were operated in force control, whereas flexion-extension, adduction-abduction, and internal-external rotation were manipulated in displacement control. Resulting femoral head translations and joint reaction torques were recorded and evaluated. Subsequently, the mean-centered range of femoral head displacements and peak signed joint restraint torques were calculated and compared.

RESULTS

During simulated gait and sitting, the mean range of AP femoral head displacements with respect to intact exceeded 1% of the femoral head diameter after creating portals, T-Caps, and partial T-Cap repair (Wilcoxon signed rank P < .05); the mean ranges of ML displacements did not. Deviations in femoral head kinematics varied by capsule stage but were never very large. No consistent trends with respect to alterations in peak joint restrain torques were observed.

CONCLUSIONS

In this cadaveric biomechanical study, capsulotomy and repair minimally affected resultant femoral head translation and joint torques during simulated ADLs.

CLINICAL RELEVANCE

The tested ADLs appear safe to perform after surgery, regardless of capsular status, because adverse kinematics were not observed. However, further study is required to determine the importance of capsular repair beyond time-zero biomechanics and the resultant effect on patient-reported outcomes.

Capsular Management During Hip Arthroscopy

PURPOSE OF REVIEW

Hip arthroscopy is widely used for the management of intra-articular pathology and there has been growing interest in strategies for management of the hip capsule during surgery. The hip capsule is an essential structure that provides stability to the joint and it is necessarily violated during procedures that address intra-articular pathology. This article reviews different approaches to capsular management during hip arthroscopy including anatomical considerations for capsulotomy, techniques, clinical outcomes, and the role of routine capsular repair. This article also reviews the concept of hip microinstability and its potential impact on capsular management options as well as iatrogenic complications that can occur as a result of poor capsular management.

RECENT FINDINGS

Current research highlights the key functional role of the hip capsule and the importance of preserving its anatomy during surgery. Capsulotomies that involve less tissue violation (periportal and puncture-type approaches) do not appear to require routine capsular repair to achieve good outcomes. Many studies have investigated the role of capsular repair following more extensive capsulotomy types (interportal and T-type), with most authors reporting superior outcomes with routine capsular repair. Strategies for capsular management during hip arthroscopy range from conservative capsulotomy techniques aimed to minimize capsular violation to more extensive capsulotomies with routine capsule closure, all of which have good short- to mid-term outcomes. There is a growing trend towards decreasing iatrogenic capsular tissue injury when possible and fully repairing the capsule when larger capsulotomies are utilized. Future research may reveal that patients with microinstability may require a more specific approach to capsular management.

Superior outcomes after arthroscopic treatment of femoroacetabular impingement and labral tears with closed versus open capsule

PURPOSE

The purpose of the study was the clinical evaluation of the capsular management with arthroscopic treatment of femoroacetabular impingement and labral tears by comparing the functional outcomes of closed versus open capsule.

METHODS

Patients with a median age of 38 years (18-55), clinical and radiological features of FAI and/or labral tear, and non-arthritic non-dysplastic hips were selected for arthroscopic treatment. Capsulotomy was performed primarily as an interportal section, then a distal extension preserving the zona orbicularis was added. The study compared two matched groups: patients with open capsule versus patients with closed capsule. Clinical outcomes were assessed by Non-Arthritic Hip Score, hip outcome scores of daily living activities and sports-specific scales. Scores were collected preoperatively and 6 months, 2 years and 5 years postoperatively. Rate of revision arthroscopy and conversion to total hip arthroplasty were used for comparing groups. Minimal clinically important differences were calculated for both groups.

RESULTS

The study included 42 patients in the OC group and 44 patients in the CC group. Significant improvement of postoperative PROMs was recorded in both groups compared to preoperative scores. CC group significantly improved more than the OC group based on NAHS, HOS-ADL and HOS-SSS over all check points except for NAHS and HOS-ADL at 6 months, which were statistically non-significant. A non-significant difference was observed in the percentage of patients who met the MCID for all reported outcome scores at 5 years in both groups. The rate of reoperation was similar in both groups, but with different indications.

CONCLUSION

Arthroscopic treatment of FAI and labral repair with complete closure of the hip capsule led to significantly improved functional outcomes after 5 years follow-up compared with open capsule. Closed capsule can provide greater improvement in the sports-specific outcomes at early follow-up. Controlled capsulotomy limited by zona orbicularis did not produce instability at any postoperative stage. Similar proportions of patients achieved minimal clinically important difference, and similar rates of reoperation were reported in both groups.

LEVEL OF EVIDENCE

III.

The Gluteus Medius Experiences Significant Excursion With Hip Flexion

Purpose

To evaluate the effect of hip flexion and rotation on excursion of the gluteus medius (Gmed) and minimus (Gmin) myotendinous unit.

Methods

Seven hips from 4 cadaveric specimens (males, 68.5 ± 18.3 years old) were dissected to isolate the Gmed posterior and lateral insertions and the Gmin proximal and distal insertions. Sutures were placed from tendon insertions through origins created in the iliac fossa to simulate the myotendinous unit. A load of 10N was applied. Myotendinous excursion was measured at 10° hip extension and 0°, 45°, and 90° of hip flexion in neutral rotation, and from maximum internal and external rotation in 90° flexion. The amount of abduction and rotation was also measured at each flexion position with 20N applied to each tendon. Repeated-measures analysis of variance with Tukey post hoc was used for statistics.

Results

Gmed-lateral excursion ranged from 2.4 ± 0.4 mm in 10° of hip extension to 23.0 ± 1.5 mm in 90° of flexion (P < .001), and Gmed-posterior excursion ranged from 0.92 ± 0.5 mm in 10° of extension to 38.1 ± 1.1 mm in 90° of flexion (P < .001). Gmin excursion shortened with hip flexion from 4.2 ± 0.3 mm in 10° of extension to -0.2 ± 1.5 mm in 90° of flexion (Gmin-prox: P = .525, Gmin-distal: P < .001). At 90° flexion from maximum internal to maximum external rotation, Gmin-distal and proximal demonstrated a 92.6% and 51.3% increase in excursion, respectively (P < .001). Gmed-lateral and Gmed-posterior demonstrated 49.4% and 23.1% increase in excursion with external rotation, respectively (P < .001).

Conclusions

The Gmed myotendinous unit undergoes significant excursion with hip flexion, whereas both Gmed and Gmin had significant excursion with femoral external rotation in 90° flexion.

Clinical Relevance

It is important to understand whether active or passive hip flexion or rotation in the early postoperative period causes excessive strain to an abductor tendon repair. We found that consideration should be given to limit flexion after Gmed repair and external rotation after Gmed or Gmin repairs.

Knotless Implant for Arthroscopic Hip Capsule Closure

The hip joint capsule plays a significant role in maintaining hip stability, including translation and rotation. Hip capsular closure or plication has been shown to increase stability of the joint following capsulotomy in hip arthroscopy for the treatment of femoroacetabular impingement syndrome (FAIS) and/or associated labral tears. This technique article describes a knotless method of closing the hip capsule.

Cadaveric Biomechanical Evaluation of Capsular Constraint and Microinstability After Hip Capsulotomy and Repair

Background:

It remains unclear if capsular management contributes to iatrogenic instability (microinstability) after hip arthroscopy.

Purpose:

To evaluate changes in torque, stiffness, and femoral head displacement after capsulotomy and repair in a cadaveric model.

Study Design:

Controlled laboratory study.

Methods:

A biomechanical analysis was performed using 10 cadaveric hip specimens. Each specimen was tested under the following conditions: (1) intact, (2) portals, (3) interportal capsulotomy (IPC), (4) IPC repair, (5) T-capsulotomy (T-cap), (6) partial T-cap repair, and (7) T-cap repair. Each capsular state was tested in neutral (0°) and then 30°, 60°, and 90° of flexion, with forces applied to achieve the displacement-controlled baseline limit of external rotation (ER), internal rotation (IR), abduction, and adduction. The resultant end-range torques and displacement were recorded.

Results:

For ER, capsulotomies significantly reduced torque and stiffness at 0°, 30°, and 60° and reduced stiffness at 90°; capsular repairs failed to restore torque and stiffness at 0°; and IPC repair failed to restore stiffness at 30° (P < .05 for all). For IR, capsulotomies significantly reduced torque and stiffness at 0°, 30°, and 60° and reduced stiffness at 90°; and capsular repairs failed to restore torque or stiffness at 0°, 30°, and 60° and failed to restore stiffness at 90° (P < .05 for all). For abduction, IPC significantly decreased torque at 60° and 90° and decreased stiffness at all positions; T-cap reduced torque and stiffness at all positions; IPC repair failed to restore stiffness at 0° and 90°; and T-cap repair failed at 0°, 60°, and 90° (P < .05 for all). For adduction, IPC significantly reduced torque at 0° and reduced stiffness at 0° and 30°; T-cap reduced torque at 0° and 90° and reduced stiffness at all positions; IPC repair failed to restore stiffness at 0° and 90°; and T-cap repair failed at 0°, 60°, and 90° (P < .05 for all). There were no statistically significant femoral head translations observed in any testing configurations.

Conclusion:

Complete capsular repair did not always restore intact kinematics, most notably at 0° and 30°. Despite this, there were no significant joint translations to corroborate concerns of microinstability.

Clinical Relevance:

Caution should be employed when applying rotational torques in lower levels of flexion (0° and 30°).