Safe angle for suture anchor insertion during acetabular labral repair

Portal Selection for Suture Anchor Placement During Hip Arthroscopic Labral Repair: A Study Based on 3-Dimensional Model Reconstruction

Background

Arthroscopic suture repair is the main treatment option for hip labral tears; however, anchor insertion and placement from arthroscopic portals is difficult.

Purpose

To quantitatively evaluate the safety of various arthroscopic portals for suture anchor placement during hip labral repair.

Study Design

Descriptive laboratory study.

Methods

The computed tomography scans of 20 patients with normally developed hip joints were used to create 3-dimensional models. The distances from the anchor to the articular cartilage (DAC) and from the acetabular insertion point to the cortical bone (DCB) were measured in the anterolateral portal (AL), posterolateral portal (PL), midanterior portal (MAP), medial MAP, and 3 distal anterolateral accessory portals (DALAs): DALA-proximal, DALA-middle, and DALA-distal. Labral tears were divided into anterior (4, 3, and 2 o'clock), lateral (1, 12, and 11 o'clock), and posterior (10, 9, and 8 o'clock) acetabular zones, and the Kruskal-Wallis and Mann-Whitney U test were used to compare DAC and DCB in the zones. The success rate was defined as anchors placed with DAC ≥1 mm and DCB ≥15 mm.

Results

The DAC was significantly smaller in the AL at 1 o'clock (0.68 ± 0.32 mm; P < .001) and 12 o'clock (0.37 ± 0.30 mm; P < .001), and in the PL at 12 o'clock (-0.35 ± 0.38 mm; P < .001) and 11 o'clock (0.60 ± 0.24 mm; P < .001). The DCB was significantly smaller in the DALA-P at 3 o'clock (8.93 ± 2.12 mm; P < .001) and 11 o'clock (9.59 ± 2.84 mm; P < .001), the MAP at 12 o'clock (13.76 ± 3.89 mm; P < .001) and 11 o'clock (0.27 ± 0.27 mm; P < .001), and the MMA at 12 o'clock (5.96 ± 2.31 mm; P < .001) and 11 o'clock (0 mm; P < .001). Success rates were high for MAP and MMA between 4 o'clock and 1 o'clock, for DALA-proximal at 12 o'clock, for AL at 11 o'clock, and for PL between 10 o'clock and 8-o'clock.

Conclusion

There were significant differences in the success rate of anchor placement using different portals during hip arthroscopic labral repair.

Clinical Relevance

MAP is recommended for labral repair between 4 o'clock and 1 o'clock, DALA-P is recommended between 2 o'clock and 12 o'clock, AL is suitable at 11 o'clock, and PL is suitable between 10 o'clock and 8 o'clock.

Bone Volumes and Trajectory Angles for Acetabular Anchor Placement Can Be Optimized

Purpose

The purpose of this study was to determine the optimal anchor placement and trajectory when repairing acetabular labral tears during hip arthroscopy with the primary focus on the 12 to 3 o’clock positions on the acetabular rim.

Methods

Three-dimensional computational models of the pelvis were generated from 13 cadaveric specimens using 3D slicer medical imaging software. A set of cones, consistent with the dimensions of a commonly used sutured anchor, were virtually embedded into the models at the 12, 1, 2, and 3 o’clock positions around the acetabulum. Mirror images of the cone were extended toward the superficial aspect of the hip. The volume of bone occupied by the virtual anchor, the trajectory angle, and the volume of overlap between adjacent anchor locations were calculated.

Results

Bone volume was significantly greater at the 1 o’clock position (4196.2 [1190.2] mm³) compared with all other positions (P < .001). The 3 o’clock position had the smallest volume (629.2 [180.0] mm³) and was also significantly less than the 12 (P < .001) and 2 o’clock (P = .014) positions). The trajectory angle of 32.04 [5.05]°) at the 1 o’clock position was significantly greater compared with all other positions (P < .001). The least amount of adjacent position overlap occurred between the 2 and 3 o’clock positions (.12 [.42] mm³), and this was statistically smaller than the overlap between cones at the 12 and 1 o’clock positions (214.28 [251.88] mm³; P = .029) and the 1 and 2 o’clock positions (139.51 [177.14] mm³; P = .044).

Conclusions

Trajectory angles and the thickness of bone around the acetabulum were the greatest at the 12 to 1 o’clock positions, with the 1 o’clock position identified as that with the largest trajectory angle for safe anchor insertion.

Clinical Relevance

The use of a single, workhorse portal, for anchor insertion may not be recommended and careful selection of a portal allowing a direct approach should be used for anterior anchor insertion.

Fluoroscopy-Guided Suture Anchor Placement Yields Excellent Accuracy for Arthroscopic Acetabular Labral Repair: A Cadaveric Study

Purpose

To determine the accuracy of fluoroscopy-guided suture anchor placement for arthroscopic acetabular labral repair in cadaveric hip specimens.

Methods

Two sports medicine fellowship–trained surgeons performed arthroscopic hip surgery on 6 cadaveric specimens each. Suture anchors were placed at the 11-, 12-, 1-, 2-, 3-, and 4-o’clock positions of the acetabulum in each specimen using a previously described fluoroscopically guided technique. Gross dissection and thin-cut computed tomography scans were performed to assess for accuracy. The insertion angle between the subchondral bone and the drill bit immediately prior to suture anchor insertion was measured, and fluoroscopic visualization of the subchondral bone at each clock-face position was qualitatively graded as good, fair, or poor by 2 independent reviewers.

Results

Overall, 90.3% of attempts (65 of 72) were entirely intraosseous, 5.5% (4 of 72) perforated the articular cartilage, and 4.2% (3 of 72) perforated the far cortex, rates that are comparable with those in previous cadaveric studies. There was no statistically significant difference in accuracy between the surgeons (P = .42) or between the various clock-face positions (P = .63). Neither the insertion angle (P = .26) nor visualization of the subchondral bone (P = .35) was significantly correlated with accuracy by gross dissection.

Conclusions

In a cadaveric hip arthroscopy model, fluoroscopy-guided suture anchor placement yields excellent accuracy rates, similar to non–image-guided techniques.

Clinical Relevance

Intra-articular suture anchor placement and intrapelvic suture anchor placement are known complications of arthroscopic acetabular labral repair. Fluoroscopically guided suture anchor placement can be a useful tool for hip arthroscopy surgeons performing acetabular labral repair and reconstruction, potentially reducing the risk of these complications.

Perpendicular drill bit alignment provides a practical guidance to determine the appropriate suture anchor insertion angle during acetabular labral repair

The safe acetabular rim angle is an anatomical measurement used to determine the safety margin when inserting suture anchors. The purpose of the present study was to find out whether aligning the drill bit perpendicularly during arthroscopic surgery can provide a reference point for determining an appropriate angle to facilitate the suture anchor insertion and to prevent extra- and intra-articular perforations. One hundred computed tomographic hips were used to reconstruct three-dimensional acetabular hip models. Each model was radially sectioned at the 4 o’clock, 3 o’clock and anterior inferior iliac spine (AIIS) positions (that corresponded mainly to the 2:20 clock position). A perpendicular reference line, representing a perpendicular drill bit alignment, was drawn for each position within the acetabular model, and its relation to the safe acetabular rim angle was measured. The length of the perpendicular reference line and the effect of gender on measurements were also evaluated. The mean safe acetabular rim angle at the 3 o’clock position was significantly smaller compared to other clock positions (P < 0.001). The perpendicular reference line was located out of the safe acetabular rim angle in 28 cases (%28), mostly in female acetabula at the 3 o’clock position, and relative to the perpendicular reference line the required minimal angle was 4° ± 2.3° to place the anchor in the safe acetabular rim angle to avoid extra-articular perforation. The perpendicular reference line was shortest at the 3 o’clock position, and its mean length was shorter in female acetabula at all clock positions (P < 0.001). Aligning the drill bit perpendicular to the acetabular opening plane during an arthroscopic anchor placement is a practical way to estimate and target the position of the safe acetabular rim angle to avoid anchor perforations. Based on measurements from a perpendicularly aligned drill bit, the drill bit should be directed towards the joint minimally by 4° to avoid extra-articular perforations and maximally by 30° to avoid intra-articular perforations.

Biomechanical comparison of knotless vs. knotted suture anchors in the acetabular rim with respect to bone density

BACKGROUND

Acetabular labral tears are managed with suture anchors providing good clinical outcomes. Knotless anchors are easier to use and have a quicker insertion time compared to knotted anchors. The purpose of this study was to compare the biomechanical behavior of two different anchor designs (knotted vs. knotless) in ultimate load testing in correlation with bone density in the acetabular rim.

METHODS

Eighteen knotted Bio-FASTak and seventeen knotless PushLock anchors (both: Arthrex Inc., Naples, FL, USA) were inserted in the rims of two human acetabula, with known bone density distribution. The anchors were subjected to load-to-failure tests. Anchors were additionally tested in solid polyurethane foam with defined densities.

FINDINGS

The Bio-FASTak group showed higher survival rates at 1, 2, and 3 mm displacement and was able to withstand significantly higher loads at 3 mm displacement (p = 0.031). There was no statistically significant difference in stiffness (p = 0.087), yield- (p = 0.190), and ultimate load (p = 0.222) between the two groups. Only the PushLock group showed correlation between bone volume over total volume (BV/TV) and stiffness (R = 0.750, p = 0.086) and between BV/TV and yield load (R = 0.838, p = 0.037). Experiments on solid polyurethane foam confirmed the correlation between the mechanical properties and tissue density for the same anchor.

INTERPRETATION

PushLock shows similar biomechanical properties to the Bio-FASTak, but eliminates knot tying and potentially abrasive knots. In addition, biomechanical properties of the PushLock are governed by local bone density.

Acetabular Subchondral and Cortical Perforation During Labral Repair With Suture Anchors: Influence of Portal Location, Curved Versus Straight Drill Guides, and Drill Starting Point

PURPOSE

To evaluate the impact of the portal used for drilling, the position of the drill guide on the acetabular rim, and the use of straight versus curved drill guides on drill perforation of the acetabular subchondral bone and the outer cortex of the acetabulum.

METHODS

Sixty acetabular models were marked at the 3-, 2-, 1-, 12-, and 11-o'clock positions. Simulated anterior, anterolateral, and distal anterolateral accessory (DALA) portals were created. Twelve groups of 5 acetabula were drilled at each clock-face position using all combinations of variables.

RESULTS

A total of 38 of 300 drillings (12.7%) perforated the subchondral bone, and 45 of 300 (15%) breached the outer cortex. Drilling from the anterior, anterolateral, and DALA portals perforated the acetabular subchondral bone on 21 of 100 attempts (21%), 17 of 100 attempts (17%), and 0 of 100 attempts (0%), respectively (P < .001), and perforated the outer acetabular cortex on 36 of 100 attempts (36%), 1 of 100 attempts (1%), and 8 of 100 attempts (8%), respectively (P < .001). The use of a curved or straight drill guide did not make a statistically significant difference. Drilling with a starting point on the acetabular rim perforated the acetabular subchondral bone on 29 of 150 attempts (19.3%) compared with 9 of 150 attempts (6%) when the starting point was 2 mm removed from the acetabular rim (P < .001).

CONCLUSIONS

The use of the DALA portal and a drill starting point slightly off the acetabular rim was associated with the lowest rate of acetabular subchondral perforation and is recommended to reduce the risk of iatrogenic chondral injury.

CLINICAL RELEVANCE

Iatrogenic chondral injury is a relatively common complication of hip arthroscopy. Increased awareness of factors associated with drill perforation during suture anchor placement can help surgeons mitigate this risk.

Fluoroscopy-Guided Suture Anchor Placement for Acetabular Labrum Repair

A narrow safe angle exists for placing suture anchors into the acetabular rim during arthroscopic acetabular labrum repair. Intra-articular suture anchor placement has been reported, and cadaver studies have shown the highest risk of errant suture anchor placement at the anterior acetabular rim. We describe a technique using intraoperative fluoroscopy to guide suture anchor placement into the anterior and superior acetabular rim, which may reduce the risk of iatrogenic injury during arthroscopic acetabular labrum repair.

What Makes Suture Anchor Use Safe in Hip Arthroscopy? A Systematic Review of Techniques and Safety Profile

PURPOSE

To perform a systematic review that assesses the current literature on suture anchor placement for the purpose of identifying factors that lead to suture anchor perforation and techniques that reduce the likelihood of complications. It was hypothesized that suture anchor placement in hip arthroscopy would generally be safe, with the exception of the complications of articular cartilage violation and psoas tunnel perforation. Perioperative factors, related to patient, surgeon, and technical variables, may influence the safety of suture anchor insertion.

METHODS

Three databases (PubMed, Ovid MEDLINE, and Embase) were searched, and 2 reviewers independently screened the resulting literature. The inclusion criteria were clinical and biomechanical studies examining the use of suture anchors in hip arthroscopy. The methodologic quality of all included articles was assessed using the Methodological Index for Non-Randomized Studies criteria and the Cochrane risk-of-bias assessment tool. Results are presented according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using descriptive statistics.

RESULTS

We included 14 studies in this review, comprising 4 case series (491 patients; 56.6% female patients; mean age, 33.9 years), 9 controlled cadaveric or laboratory studies (111 cadaveric hips and 12 synthetic acetabular bone blocks; 42.2% female hips; mean age, 60.0 years) with a mean Quality Appraisal for Cadaveric Studies score of 11, and 1 randomized controlled trial (37 hips; 55.6% female hips; mean age, 34.2 years). Anterior cortical perforation into the psoas tunnel by suture anchors led to pain and impingement of pelvic neurovascular structures. The anterior acetabular positions (3- to 4-o'clock position) had the thinnest bone, smallest rim angles, and highest incidence of articular perforation. Drilling angles from 10° to 20° measured off the coronal plane were acceptable. The midanterior and distal anterolateral portals were used successfully, with 1 study reporting difficulty placing anchors at anterior locations through the distal anterolateral portal. One study showed that curved suture anchor drill guides allow for a better trajectory away from the articular cartilage. Small-diameter (≤1.8-mm) all-suture anchors had a lower in vivo incidence of articular perforation with similar stability and pullout strength to other anchor types in biomechanical studies.

CONCLUSIONS

Suture anchors at anterior acetabular rim positions (3- to 4-o'clock position) should be inserted with caution. Large-diameter (≥2.3-mm) suture anchors increase the likelihood of articular perforation without increasing labral stability. Inserting small-diameter (≤1.8-mm) all-suture anchors from 10° to 20° drilling angles may increase safe insertion angles from all cutaneous portals. Direct arthroscopic visualization, the use of fluoroscopy, distal-proximal insertion, and the use of nitinol wire can help prevent articular violation.

LEVEL OF EVIDENCE

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

Factors Associated with the Risk of Articular Surface Perforation during Anchor Placement for Arthroscopic Acetabular Labral Repair

Background

The purpose of this study was to evaluate factors associated with the risk of articular surface perforation during anchor placement for arthroscopic acetabular labral repair using follow-up computed tomographic arthrography (CTA).

Methods

Forty-six patients (29 males and 17 females) underwent arthroscopic labral repair using 142 suture anchors (55 large anchors and 87 small anchors). The patients were followed with CTA 1 year postoperatively. Anchor position was assessed by the insertion angle and the distance of the suture anchor tip from the articular cartilage. The incidence of malposition of suture anchors was assessed in follow-up CTA. The location and incidence of malposition were compared between two groups divided according to the diameter of suture anchor.

Results

The mean insertion angle and distance were significantly different between the groups. Of the 142 anchors, 15 (11%) were placed in the cartilage-bone transitional zone. Articular involvement was most common at the 3 o'clock position of the suture anchor (six out of 33 anchors, 18.2%). Both the insertion angle and distance showed small values in the articular involvement group.

Conclusions

The radiographic analysis of the placement of suture anchors after arthroscopic labral refixation based on follow-up CTA demonstrates that articular involvement of anchors is related to the location on the acetabular rim (clock position) and anchor diameter.

Are pelvic anatomical structures in danger during arthroscopic acetabular labral repair? Definition of safe bone depth

PURPOSE

The purpose of this study was to evaluate safe depth for suture anchor insertion during acetabular labral repair and to determine the neighbouring structures at risk during drilling and anchor insertion.

METHODS

Ten human cadaveric hips (six males and four females) were obtained. Acetabular labral surface was prepared and marked for right hips as 12, 1 and 3 o'clock positions, for left hips 12, 11 and 9 o'clock positions. Those were defined as anterior, anterior-superior and superior zones, respectively. These labral positions were drilled at defined zones. After measurements, depth of the bone at 10° and 20° drill angles on zones was compared statistically.

RESULTS

Acetabular bone widths at investigated labral insertion points did not statistically differ. A total of 14 injuries in 60 penetrations occurred (23.3 %) with free drill penetrations, and no injuries occurred with stopped drill penetrations. The bone depth was gradually decreasing from 10° to 20° drill angles and from anterior to superior inserting zones without significant importance. The risk of perforation to the pelvic cavity started with 20 mm drill depth, and the mean depth for all insertions was calculated as 31.7 mm (SD 2.6).

CONCLUSIONS

It is anatomically possible that some pelvic structures sustain iatrogenic injury during acetabular drilling for anchor placement. Being aware of mean pelvic vault is important in which drilling after excessive pincer rim trimming could easily decrease the depth of acetabular bone without a standard. Careful drilling by using stopped drill bit is crucial to prevent iatrogenic injury.

Clinical outcomes after arthroscopic acetabular labral repair using knot-tying or knotless suture technique

BACKGROUND

The purpose of the study was to compare the clinical results of arthroscopic labral repair using knot-tying and knotless suture anchor techniques for patients with labral tears.

METHODS

From September 2012 to May 2013, we performed a randomized, prospective analysis of 40 hips with labral tears treated with arthroscopic labral repair via knot-tying (group A) or knotless suture anchors (group B). A total of 33 patients were treated for labral tears, and 7 of them received bilateral labral repair. Outcomes and intraoperative parameters were prospectively measured with the UCLA score, the modified Harris Hip Score (MHHS), the Hip disability and Osteoarthritis Outcome Score (HOOS), and the Hip Outcome Score (HOS).

RESULTS

Three patients (3 hips) were lost to follow up. A total of 37 hips (30 patients) were finally analyzed: 19 hips in group A and 18 in group B. The mean traction time for group A and group B was 72.2 versus 68.7 min, respectively (p = 0.314). Although the clinical outcome scores in both groups improved between the initial and final visits, there was no difference in measurements parameters between the two groups. Survival rate, using reoperation or progression of osteoarthritis as the primary end points, was 100 %. 83 % of cases had excellent and good MHHS scores after 2 years of follow-up. During arthroscopic surgery, the drill penetrated the closing subchondral area or the joint in three hips. There was no progression of arthritic change at the latest follow-up.

CONCLUSIONS

Labral repair with either knot-tying or knotless suture anchor resulted in significant postoperative improvements and no difference between the two groups after 2 years of follow-up.

Safe Angle of Anchor Insertion for Labral Repair During Hip Arthroscopy

PURPOSE

To compare the use of the distal anterolateral accessory (DALA) portal with the anterolateral (AL) and midanterior (MA) portals during arthroscopic hip labral repair.

METHODS

Standard AL, MA, and DALA portals were created on 6 cadaveric hip specimens. Four 2.4-mm pins were placed in the acetabular rim to the depth of a standard anchor using a drill guide. Pins were placed in the 12 to 3 o'clock positions. The specimens then underwent computed tomographic scans with the pins left in place, and the distance from the pin to the articular surface was calculated at different depths of insertion.

RESULTS

In the anterior location, the average starting distance for the DALA pin was 2.05 mm and for the MA pin it was 2.51 mm from the articular surface (P = .29). Statistically significant differences between the DALA and MA pins were found at depths of 6 mm (P = .04) and 9 mm (P = .03). In the superior location, the average starting distance for the DALA pin was 2.40 mm and for the AL pin it was 2.62 mm from the articular surface (P = .34). Statistically significant differences between the DALA and AL pins were found at depths of 6 mm (P = .02), 9 mm (P = .01), 12 mm (P = .01), 15 mm (P = .04), and 18 mm (P = .04).

CONCLUSIONS

The DALA portal allows pins to be placed at a greater distance from the articular surface than the MA and AL portals when using a straight drill guide. This may decrease the incidence of intra-articular penetration during arthroscopic hip labral repair.

CLINICAL RELEVANCE

Intra-articular penetration of a drill bit or anchor is an iatrogenic complication that can occur during labral repair. By using the DALA portal instead of the AL and MA, the anchor can be safely placed on the acetabular rim and directly away from the articular surface, decreasing the chance for this complication.

Clinical Outcomes After Arthroscopic Hip Labral Repair Using Looped Versus Pierced Suture Techniques

BACKGROUND

With an improved understanding of the importance of the labrum, labral repair is replacing labral debridement as a component of hip arthroscopy for femoroacetabular impingement. Labral repair can be performed by passing suture limbs either around (looped) or through (pierced) the labral tissue.

PURPOSE

To determine whether there is any clinical difference between these different labral repair techniques.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A prospective data registry was queried for patients who underwent primary hip arthroscopy with labral repair from 2009 to 2011. Patients older than 18 years who had undergone labral repair were included in the study. Exclusion criteria included previous hip surgery, avascular necrosis, joint space less than 2 mm, and labral reconstruction or augmentation. Patients were grouped based upon the 3 labral repair techniques: looped, pierced, or combined. Statistical equivalence testing was performed to evaluate the primary outcome measure, the Hip Outcome Score-activities of daily living subscale (HOS-ADL). Other measures included the HOS-sport subscale (HOS-Sport), modified Harris hip score (mHHS), Short Form-12 (SF-12), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and patient satisfaction with outcome (1-10 scale; 10 = very satisfied).

RESULTS

Preoperative scores improved in the looped group (HOS-ADL, from 68 to 91; mHHS, from 64 to 83; HOS-Sport, from 51 to 81; and WOMAC, from 23 to 9), the pierced group (HOS-ADL, from 64 to 89; mHHS, from 62 to 83; HOS-Sport, from 46 to 77; and WOMAC, from 34 to 12), and the combined group (HOS-ADL, from 64 to 89; mHHS, from 63 to 83; HOS-Sport, from 52 to 79; and WOMAC, from 26 to 12). Median patient satisfaction in all groups was 9.0. The 3 labral repair groups were shown to be statistically and clinically equivalent (P < .05) with respect to the validated HOS-ADL to within a clinically irrelevant threshold at mean 36-month follow-up. In addition, there were no differences in secondary outcome measures or in the revision rate (looped, 7% [14/209], pierced, 8% [5/65], and combined, 6% [5/83]).

CONCLUSION

This study showed equivalent HOS-ADL outcomes between looped, pierced, and combined labral repairs. Secondary outcome measures, including failure and revision rates, were not significantly different among the groups. Thus, suture type did not influence outcomes.

Psoas tunnel perforation-an unreported complication of hip arthroscopy

The utilization of hip arthroscopy is rapidly increasing due to improved arthroscopic techniques and training, better recognition of pathology responsible for non-arthritic hip pain and an increasing desire for minimally invasive procedures. With increasing rates of arthroscopy, associated complications are also being recognized. We present a series of six patients who experienced psoas tunnel perforation during anchor insertion from the distal anterolateral portal during labral repair. All patients underwent prior hip arthroscopy and labral repair and presented with persistent symptoms at least partly attributable to magnetic resonance imaging (MRI)-documented psoas tunnel perforation. Their clinical records, operative notes and intra-operative photographs were reviewed. All patients presented with persistent pain, both with an anterior impingement test and resisted hip flexion. MRI imaging demonstrated medial cortical perforation with anchors visualized in the psoas tunnel, adjacent to the iliopsoas muscle. Four patients have undergone revision hip arthroscopy, whereas two have undergone periacetabular osteotomies. All patients had prominent anchors in the psoas tunnel removed at the time of surgery, with varying degrees of concomitant pathology appropriately treated during the revision procedure. Care must be utilized during medial anchor placement to avoid psoas tunnel perforation. Although this complication alone was not the sole cause for revision in each case, it may have contributed to their poor outcome and should be avoided in future cases. This can be accomplished by using a smaller anchor, inserting the anchor from the mid-anterior portal and checking the drill hole with a nitinol wire prior to anchor insertion.

Safe suture anchor insertion for anterior and posterior hip labral repair

We sought to define bone thickness in relation to the chondral surface at various depths along the anterior and posterior acetabular rim and safe portals for anchor insertion in these regions. Six cadaveric pelvises were mounted on a custom jig. A custom guide was attached to simulate anterolateral (AL), mid-anterior (MA), distal anterolateral (DALA) and posterolateral (PL) arthroscopy portals. Anterior 3 o’clock and 4 o’clock positions were drilled using MA and DALA portals. Posterior 8 o’clock to 11 o’clock positions were drilled using a 1.4-mm drill bit from the PL portal. At depths of 5, 10 and 15 mm, the distance from the drill to the intra and extra-articular surfaces was measured using a custom caliper. Mean distance between drill hole and articular surface for anterior and posterior positions ranged from 1.61 to 2.75 mm at 5 mm. The smallest distance between the drill hole and articular surface and the largest width between drill hole and the extra-articular surface were at the 4 o’clock position. No difference between the MA and DALA portals were noted for the anterior positions. For the posterior rim positions, the distance on the articular side remained consistent throughout. For the posterior positions, only the PL portal was utilized. Both the MA or DALA portals can be utilized for safe drilling of the anterior rim positions. The posterior positions can all be safely drilled with a relatively good bone margin using the PL portal, but use of the MA or DALA portals resulted in extra-articular cortical perforation in all cases.

Anchor-induced chondral damage in the hip

The purpose of this study is to investigate the outcomes from anchor-induced chondral damage of the hip, both with and without frank chondral penetration. A multicenter retrospective case series was performed of patients with chondral deformation or penetration during initial hip arthroscopic surgery. Intra-operative findings, post-surgical clinical courses, hip outcome scores and descriptions of arthroscopic treatment in cases requiring revision surgery and anchor removal are reported. Five patients (three females) of mean age 32 years (range, 16-41 years) had documented anchor-induced chondral damage with mean 3.5 years (range, 1.5-6.0 years) follow-up. The 1 o'clock position (four cases) and anterior and mid-anterior portals (two cases each) were most commonly implicated. Two cases of anchor-induced acetabular chondral deformation without frank penetration had successful clinical and radiographic outcomes, while one case progressed from deformation to chondral penetration with clinical worsening. Of the cases that underwent revision hip arthroscopy, all three had confirmed exposed hard anchors which were removed. Two patients have had clinical improvement and one patient underwent early total hip arthroplasty. Anchor-induced chondral deformation without frank chondral penetration may be treated with close clinical and radiographic monitoring with a low threshold for revision surgery and anchor removal. Chondral penetration should be treated with immediate removal of offending hard anchor implants. Preventative measures include distal-based portals, small diameter and short anchors, removable hard anchors, soft suture-based anchors, curved drill and anchor insertion instrumentation and attention to safe trajectories while visualizing the acetabular articular surface.

Safety measures in hip arthroscopy and their efficacy in minimizing complications: a systematic review of the evidence

PURPOSE

The purpose of this systematic review was to evaluate the literature to determine complications of hip arthroscopy, with a secondary focus on how to minimize complications and risks.

METHODS

Two independent reviewers performed a search of PubMed for articles that contained at least 1 of the following terms: complications and hip arthroscopy, hip impingement, femoral acetabular impingement and complications, or femoroacetabular impingement (FAI) and complications. The search was limited to articles published between 1999 and June 2013. An additional search was performed for articles evaluating techniques on how to minimize complications.

RESULTS

We identified 81 studies (5,535 patients; 6,277 hips). The mean age was 35.48 years, and the mean body mass index was 25.20 kg/m(2). Of the participants, 52% were male and 48% were female. The majority of studies were Level IV Evidence (63%). A total of 285 complications were reported, for an overall rate of 4.5%. There were 26 major complications (0.41%) and a 4.1% minor complication rate. The overall reoperation rate was 4.03%. A total of 94 hips underwent revision arthroscopy. Regarding open procedures, 150 patients (93%) underwent either total hip arthroplasty or a hip resurfacing procedure. The conversion rate to total hip arthroplasty or a resurfacing procedure was 2.4%.

CONCLUSIONS

Overall, primary hip arthroscopy is a successful procedure with low rates of major (0.41%) and minor (4.1%) complications. The reoperation rate was 4.03% in our review. There is admittedly a learning curve to performing hip arthroscopy, and we present a systematic review of the complications and how to minimize these complications with careful technique and planning.

LEVEL OF EVIDENCE

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

Hip arthroscopy for challenging deformities: global pincer femoroacetabular impingement

Pincer femoroacetabular impingement occurs in focal or global forms, the latter having more generalized and typically more extreme acetabular overcoverage. Severe global deformities are often treated with open surgical dislocation of the hip. Arthroscopic technical challenges relate to difficulties with hip distraction; central-compartment access; and instrument navigation, acetabuloplasty, and chondrolabral surgery of the posterior acetabulum. Techniques addressing these challenges are introduced permitting dual-portal hip arthroscopy with central-compartment access, subtotal acetabuloplasty, and circumferential chondrolabral surgery. The modified midanterior portal in combination with a zone-specific sequence of acetabular rim reduction monitored with fluoroscopic templating enables precision subtotal acetabuloplasty. Guidelines for acetabular rim reduction include the following suggested radiographic endpoints: postoperative center-edge angle of 35°, a neutral posterior wall sign, and an anterior margin ratio of 0.5. Arthroscopic zone-specific chondrophobic rim preparation and circumferential labral reparative and reconstructive techniques and tools permit the arthroscopic treatment of these challenging deformities.

Inside out: a novel labral repair and advancement technique

Labral tears are a significant cause of hip pain and are currently the most common indication for hip arthroscopy. Compared with labral debridement, labral repair has significantly better outcomes in terms of both daily activities and athletic pursuits in the setting of femoral acetabular impingement. The techniques described in the literature all use anchor placement on the capsular aspect of the acetabular rim, which can be difficult especially anteriorly, where the rim is very thin, and has the potential for significant complications. Anchor breakage, anchor slippage into the surrounding (capsular side) soft tissue, and penetration of the cartilage surface are among the most common complications. We describe an intra-articular anchor placement technique for labral repair from inside out. This technique, because of the location of the anchor and direction of suture pull, can assist in labral advancement in cases in which the native labrum fails to create a seal because of its location away from the femoral head.

Defining a safety margin for labral suture anchor insertion using the acetabular rim angle

BACKGROUND

Suture anchors are commonly used to reattach a torn labrum to the acetabular rim. The acetabular rim anatomy is not uniform, and the safety margin for inserting suture anchors is unknown. The acetabular rim angle is an anatomic measurement that is indicative of the safety margin for inserting suture anchors.

PURPOSE

To investigate the acetabular rim angle as a function of clock position, to evaluate the effect of drill depth on the acetabular rim angle, and to evaluate the effect of rim trimming on the acetabular rim angle.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Three-dimensional acetabular models were reconstructed from computed tomography scans of 20 nonpaired cadaveric hip specimens, and the acetabular rim angle, which quantifies the angle between the subchondral margin and the outer cortex of the acetabulum, was measured from the 8- to 4-o'clock positions. At each position, the acetabular rim angle was measured for 5 drill depths (10, 12.5, 15, 20, and 25 mm) to simulate different lengths of suture anchors or drill bit depths on the acetabular rim angle. To simulate rim trimming, the acetabular rim angle was measured at the points that would become the suture anchor insertion points after 2.5- and 5-mm rim trimming.

RESULTS

Clock position, drill depth, and rim trimming all had significant effects on the acetabular rim angle (P < .0001). The acetabular rim angle was largest at the 2-o'clock and smallest at the 3-o'clock position. Greater drill depths provided smaller acetabular rim angles, whereas rim trimming provided larger acetabular rim angles.

CONCLUSION

The acetabular rim angle varied significantly as a function of the location on the acetabular rim. A shorter drill depth and a greater amount of rim trimming provided a larger acetabular rim angle.

CLINICAL RELEVANCE

Surgeons should be aware of the acetabular rim variations, especially in the anterosuperior quadrant, as well as the effects of drill depth and rim trimming, when selecting the optimal insertion angle for suture anchor placement to avoid articular cartilage penetration. The acetabular safety angle was smallest at the 3-o'clock position. Therefore, extra care must be taken when drilling or inserting anchors around the 3-o'clock position.

Labral base refixation in the hip: rationale and technique for an anatomic approach to labral repair

Recent literature has defined the importance of anatomic repair in shoulder and knee arthroscopy. New advances in hip arthroscopy have created opportunities to apply the principle of anatomic repair to the hip. To address the obstacles in the restoration of labral anatomy, we describe an anatomic approach to labral refixation. We reviewed the literature on biomechanics of the labrum to identify the factors that are essential to the function of the labrum. Existing techniques for arthroscopic labral repair and potential challenges in restoration of labral anatomy were reviewed. A list of criteria for anatomic labral repair was created, and a technique for anatomic labral base refixation was developed. The technique incorporates the understanding of the function and biomechanical role of the labrum and builds on existing techniques to fulfill the criteria for restoration of anatomy. Our purpose was to review the anatomy, biomechanics, and existing repair techniques of the labrum, as well as to describe the rationale and surgical steps for anatomic labral base refixation in the hip.

Cyclic load testing and ultimate failure strength of suture anchors in the acetabular rim

PURPOSE

To determine the resistance to cyclic stress and load-to-failure strength of several suture anchors suitable for hip arthroscopy.

METHODS

Ten polyetheretherketone (PEEK) PushLock, PEEK SutureTak, and Bio-SutureTak anchors (Arthrex, Naples, FL); Lupine Loop BR anchors (DePuy Mitek, Norwood, MA); Bio-Mini Revo anchors (ConMed Linvatec, Largo, FL); and BioRaptor 2.9 AB anchors (Smith & Nephew, Andover, MA) were inserted in rotation into different locations on the rim of 4 matched pairs of potted acetabula clamped to the base of a servohydraulic testing machine. The anchors' sutures were cyclically pulled in line with the insertion angle. Displacement at 100 and 500 cycles, yield load, ultimate failure load, and failure mode were recorded. Statistical analysis was performed.

RESULTS

Most of the displacement observed during cyclic loading occurred in the first 100 cycles, except for the BioRaptor 2.9 AB, which showed twice as much displacement at 500 cycles as at 100 cycles. The Lupine Loop BR cyclic displacement was greater than that of the PEEK PushLock (at 100 cycles also), Bio-SutureTak, and PEEK SutureTak at 500 cycles (P < .05). The BioRaptor 2.9 AB cyclic displacement was significantly greater at 100 and 500 cycles than that of the PEEK PushLock and Bio-SutureTak (P < .05). The mean ultimate failure loads for these anchors ranged from 154 N (PEEK SutureTak) to 255 N (Bio-Mini Revo) and was statistically equivalent (P = .139). Correlation analysis showed no significant associations between anchor stiffness, cyclic load displacement, or failure load.

CONCLUSIONS

Anchors with specific indications for hip arthroscopy showed very little displacement and had consistent failure loads under cyclic conditions in the acetabular rim. All hip anchors except the BioRaptor 2.9 AB showed less than 2.0 mm of displacement after 500 cycles.

CLINICAL RELEVANCE

Biomechanical testing of suture anchors designated for hip arthroscopy should be performed in the acetabular rim before their use. Suture anchors used for shoulder arthroscopy may not perform as well in the hip.