Patient-specific factors influencing the traction forces in hip arthroscopy

During Postless Hip Arthroscopy, Male Patients, High Body Mass Index, Low Beighton Scores, and Limited Range of Motion Require High Traction Force

PURPOSE

To determine the effects of demographic and anatomic factors on traction force required during postless hip arthroscopy.

METHODS

A prospectively collected database was retrospectively analyzed on patients undergoing hip arthroscopy by the senior author, including patient sex, age, body mass index (BMI), Beighton Hypermobility Score, hip range of motion in clinic and under anesthesia, hip dysplasia, acetabular version, and femoral version. All patients underwent postless hip arthroscopy under general anesthesia. At the initiation of hip arthroscopy, the traction force required to distract the hip joint was measured before and following interportal capsulotomy. Multiple regression analysis was performed to determine the effects of demographic and anatomic factors on measured distraction force.

RESULTS

In total, 352 hips (114 male, 238 female) were included with a mean age of 32.6 years and a mean BMI of 24.1 kg/m2. Mean initial traction force was 109 lbs and decreased to 94.3 lbs following capsulotomy (P < .0001). The starting traction force was significantly greater in male patients (P < .001), patients with a lack of hypermobility (Beighton Hypermobility Score of 0-2) (P = .026), and in patients with lower abduction (P < .001), lower internal rotation (P = .002), and lower external rotation (P = .012) on multiple regression analysis. When performing a subanalysis divided by sex, male patients with elevated BMI required significantly greater starting traction force (P = .014). Lateral center edge angle, sourcil angle, and the presence of hip dysplasia did not demonstrate a significant correlation with traction force.

CONCLUSIONS

Male patients, patients with reduced preoperative hip range of motion, patients with a lack of joint hypermobility, and male patients with an elevated BMI require greater initial traction force during postless hip arthroscopy.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Experimental assessment of pelvis slipping during postless traction for orthopaedic applications

BACKGROUND

The application of lower limb traction during hip arthroscopy and femur fractures osteosynthesis is commonplace in orthopaedic surgeries. Traditional methods utilize a perineal post on a traction table, leading to soft tissue damage and nerve neuropraxia. A postless technique, using high-friction pads, has been considered as a potential damage-free alternative. However, whether these pads sufficiently prevent patient displacement remains unknown. Thus, this study systematically assesses the efficacy of commercial high-friction pads (PinkPad and CarePad) in restraining subject displacement, for progressively increasing traction loads and different Trendelenburg angles.

METHODS

Three healthy male subjects were recruited and tested in supine and Trendelenburg positions (5° and 10°), using a customized boot-pulley system. Ten load disks (5 kg) were dropped at 15s intervals, increasing gradually the traction load up to 50 kg. Pelvis displacement along the traction direction was measured with a motion capture system. The displacement at 50 kg of traction load was analyzed and compared across various pads and bed inclinations. Response to varying traction loads was statistically assessed with a quadratic function model.

RESULTS

Pelvis displacement at 50 kg traction load was below 60 mm for all conditions. Comparing PinkPad and CarePad, no significant differences in displacement were observed. Finally, similar displacements were observed for the supine and Trendelenburg positions.

CONCLUSIONS

Both PinkPad and CarePad exhibited nearly linear behavior under increasing traction loads, limiting displacement to 60 mm at most for 50 kg loads. Contrary to expectations, placing subjects in the Trendelenburg position did not increase adhesion.

T, Maniar A, Mitrasinovic S, Menta SV, Ranawat A. Intraoperative traction has a negligible time-dependent influence on patient-reported outcomes after hip arthroscopy: a cohort study

The aim of this study is to determine if post-operative patient-reported outcome measures (PROMs) are influenced by hip arthroscopy traction duration. Patients from a local prospective hip arthroscopy database were retrospectively analyzed. Four hip-specific PROMs were utilized: modified Harris Hip Score (mHHS), Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sports Specific (HOS-SS), and international Hip Outcome Tool (iHOT). PROMs were collected pre-operatively and 6 months, 1 year and 2 years post-operatively. Two cohorts were created based on a cut-off corresponding to the 66th percentile for our patient cohort. Analyses were completed for each PROM at each post-operative interval with univariable statistics. Multivariable statistics were examined to identify the variables that were predictive of achieving post-operative minimal clinically important difference (MCID) at the 2-year follow-up. Overall, 222 patients met the inclusion criteria. The mean age was 32.4 ± 9.4 years, and 116 (52.3%) were female. The average traction time of the study population was 46.1 ± 12.9 min. A total of 145 patients were included in the short traction cohort (65%) with traction times of <50 min (66th percentile). No significant differences were found regarding PROM scores or MCID achievement rates between both cohorts at any post-operative period. In multivariable analyses, achievement of MCID was predicted by a decrease in traction time for all PROMs and pincer-type resection for mHSS, HOS-ADL and iHOT. There was no difference in PROMs and MCID achievement between longer and shorter traction time cohorts. On multivariable analysis, a decrease in traction time is predictive of MCID for all PROM scores and pincer-type resection was predictive of MCID for most PROM scores. Level of evidence: Level III, cohort study.

Sex-Based Differences in Prevalence, Outcomes, and Complications of Hip Arthroscopy for Femoroacetabular Impingement: A Systematic Review and Meta-analysis

Background

Trends between the sexes have been reported regarding prevalence, patient-reported outcomes (PROs), and complications of hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS), yet current results lack consensus.

Purpose

To evaluate sex-based differences after HA for FAIS in (1) prevalence of cam and pincer morphology in FAIS and (2) PROs, pain scores, and postoperative complication rates.

Study Design

Systematic review; Level of evidence, 4.

Methods

The EMBASE, PubMed, and Ovid (MEDLINE) databases were searched from establishment to February 28, 2022, according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included studies had sex-based data on prevalence, outcomes, and complications of HA for FAIS. Reviews and commentaries were excluded. Data were combined, and between-sex differences were analyzed. Meta-analyses using random-effects models were performed when possible. Pooled risk ratios (RRs) and standardized mean differences were calculated.

Results

A total of 74 studies were included (213,059 patients; 132,973 female hips [62.4%] and 80,086 male hips [37.6%]). The mean age was 30.7 ± 7.7 years among male patients and 31.1 ± 7.8 years among female patients. Male patients experienced mixed-type impingement significantly more often (39.4% vs 27.2% for female patients; RR = 0.69 [95% confidence interval [CI], 0.58-0.81]; P < .001), whereas female patients experienced pincer-type impingement more often (50.6% vs 30.8% for male patients; RR = 2.35 [95% CI, 1.14-4.86]; P = .02). Male patients had higher likelihoods of undergoing femoroplasty (89.8% vs 77.4% for female patients; RR = 0.90 [95% CI, 0.83-0.97]; P = .006), acetabuloplasty (67.1% vs 59.3% for female patients; RR = 0.87 [95% CI, 0.79-0.97]; P = .01), or combined femoroplasty/acetabuloplasty (29.2% vs 14.5% for female patients; RR = 0.63 [95% CI, 0.44-0.90]; P = .01). Although female patients showed greater improvements in Hip Outcome Score-Sport-Specific subscale (P = .005), modified Harris Hip Score (P = .006), and visual analog scale pain (P < .001), both sexes surpassed the minimal clinically important difference at 1, 2, and 5 years postoperatively. Female patients had higher complication rates (P = .003), although no sex-based differences were found in total hip arthroplasty conversion rates (P = .21).

Conclusion

Male patients undergoing HA for FAIS had a higher prevalence of mixed-type FAIS while female patients had more pincer-type FAIS. Female patients gained greater improvements in PROs, although both sexes exceeded the minimal clinically important difference, suggesting that both male and female patients can benefit from HA.

Hip Joint Venting Decreases the Traction Force Required to Access the Central Compartment During Hip Arthroscopy

Purpose

To investigate the effect of hip joint venting on the magnitude of traction force required to arthroscopically access the central compartment of the hip.

Methods

Patients who underwent hip arthroscopy for femoroacetabular impingement syndrome prospectively underwent an intraoperative traction protocol. Joint space was measured on fluoroscopic images obtained at 50 and 100 lbs of axial traction in the prevented and vented state, and joint space values were normalized to millimetric values using preoperative anteroposterior pelvis radiographs. Venting was performed by inserting a large gauge spinal needle into the hip joint through the hip capsule and removing the stylet. Joint space differences were compared with paired t-tests, Wilcoxon signed-rank tests, and McNemar tests.

Results

Fifty hips in 46 patients were included. Mean joint space before venting was 7.4 ± 2.6 mm and 13.3 ± 2.8 mm at 50 and 100 lbs of traction, respectively. Mean joint space after venting was 13.9 ± 2.3 mm and 15.5 ± 2.4 mm at 50 and 100 lbs of traction, respectively. Mean differences in joint space at 50 and 100 lbs were 6.5 mm (P < .001) and 2.2 mm (P < .001), respectively. Mean joint space at 50 lbs in the vented state was significantly greater than in the pre-vented state at 100 lbs (13.9 mm vs. 13.3 mm; P = .002). The increase in joint space between 50 and 100 lbs of traction was significantly greater in the prevented state than in the vented state (5.9 mm vs 1.6 mm; P = .021).

Conclusions

Venting the hip reduces the traction force necessary to arthroscopically visualize and instrument the central compartment of the hip by at least 50%. Further, residual negative pressurization of the hip joint remains after breaking the labral suction seal and venting effectively eliminates this phenomenon to aid in hip joint distraction at lower traction force.

Level of Evidence

Level IV, case series.

Distraction Gap Needed for Safe Central Compartment Access in Hip Arthroscopy

BACKGROUND

Sufficient distraction of the hip is the key to a safe central compartment (CC) approach in hip arthroscopy. However, an adequate distraction gap has not been scientifically identified.

PURPOSE

To determine the sufficient amount of distraction that could predict a successful CC access as well as to identify the risk factors for a failed or difficult CC access.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

All patients who underwent hip arthroscopy by a single surgeon between January 2018 and April 2019 were prospectively enrolled. We analyzed gaps of the hip on 4 C-arm fluoroscopic images: nondistraction, preoperative manual traction, preoperative maximal traction (without distension), and intraoperative maximal traction (at the end of CC procedures in a successful CC approach or after peripheral compartment procedures in a failed or difficult CC approach). A failed CC approach was defined as failure in introducing the anterolateral portal to the CC under arthroscopic control; a difficult CC approach was defined as the presence of an incomplete diagnostic round in the CC because of a small distraction. The amount of distraction was evaluated by the ratio of the distracted gap to the undistracted gap. Patients were classified into the successful CC access group (group 1) and the failed/difficult CC access group (group 2). The amount of distraction, demographic characteristics, and preoperative radiographic parameters were compared between the groups.

RESULTS

A total of 240 patients were included in this study. Group 1 consisted of 205 patients (113 males and 92 females; mean ± SD age, 34.5 ± 11.4 years), and group 2 consisted of 35 patients (27 males and 8 females; age, 32.5 ± 11.2 years). The preoperative joint space width was not significantly different between group 1 (mean ± SD, 3.89 ± 0.83 mm) and group 2 (3.68 ± 0.68 mm). The ratio of the amount of distraction at lateral gaps under all traction conditions was significantly greater in group 1 compared with group 2 (1.50 ± 0.54 vs 1.26 ± 0.35, respectively, under preoperative manual traction; 2.84 ± 0.76 vs 2.03 ± 0.63 under preoperative maximal traction; 3.36 ± 0.96 vs 2.50 ± 0.79 under intraoperative maximal traction). An increase of the lateral gap by >2.2 times (P < .001) under preoperative maximal traction and by >2.7 times (P < .001) under intraoperative maximal traction could predict successful CC access. Male sex (odds ratio [OR], 2.94; P = .017) and increased lateral center-edge angle (OR, 1.08 for every 1° increase; P = .004) were significant risk factors for failed/difficult CC access.

CONCLUSIONS

An increase of the lateral gap by >2.2 times during an unsterile traction test without joint distension could predict successful CC access. Male sex and increased lateral center-edge angle were risk factors for a failed or difficult CC access.

Postless Hip Distraction Systems Decrease the Amount of Traction Force Needed to Obtain Adequate Hip Distraction Versus a Conventional Post Hip Distractor

PURPOSE

To directly compare hip distraction distance and traction force data for hip arthroscopy performed using a post-basedsystem versus a postless system.

METHODS

Adult patients undergoing primary hip arthroscopy for femoroacetabular impingement were prospectively enrolled. Before March 26, 2019, arthroscopy was performed using a post-based system. After this date, the senior author converted to using a postless system. Intraoperative traction force and fluoroscopic distraction distance were measured to calculate hip stiffness coefficients at holding traction (k-hold) and maximal traction (k-max). We used multivariable regression analysis to determine whether postless arthroscopy was predictive of lower stiffness coefficients when controlling for other relevant patient-specific factors.

RESULTS

Hip arthroscopy was performed with a post-based system in 105 patients and with a postless system in 51. Mean holding traction force (67.5 ± 14.0 kilograms-force [kgf] vs 55.8 ± 15.3 kgf) and mean maximum traction force (96.0 ± 16.6 kgf vs 69.9 ± 14.1 kgf) were significantly lower in the postless group. On multivariable analysis, postless traction was an independent predictor of decreased k-hold (β = -31.4; 95% confidence interval, -61.2 to -1.6) and decreased k-max (β = -90.4; 95% confidence interval, -127.8 to -53.1). Male sex, Beighton score of 0, and poor hamstring flexibility were also predictors of increased k-hold and k-max in the multivariable model.

CONCLUSIONS

Postless traction systems decrease the amount of traction force required for adequate hip distraction for both maximal and holding traction forces when compared with post-based systems. Postless traction systems may help further reduce distraction-type neurologic injuries and pain after hip arthroscopy by lowering the traction force required to safely distract the hip.

LEVEL OF EVIDENCE

Level III, prospective cohort-historical control comparative study.

The diagnosis of hip microinstability is correlated with ease of intra-operative hip distraction

PURPOSE

Hip microinstability has emerged as a contributor to young adult, non-arthritic hip pain. There is a paucity of objective clinical data to identify patients with hip microinstability and guide surgical treatment. The purpose of this study was to identify the degree of distractibility in patients with and without microinstability undergoing hip arthroscopy.

METHODS

A single-surgeon series of hip arthroscopies were retrospectively reviewed from 2014-2020. All procedures were performed with paralysis on a fracture table with a perineal post where 1 turn of fine traction equates to 4 mm of axial traction. Diagnosis was recorded as isolated instability, instability plus femoroacetabular impingement (FAI), and isolated FAI. Operative reports were reviewed to collect patient demographic data, number of turns of traction required for adequate distraction of the femoral head relative to the acetabulum (10 mm), and the presence of residual subluxation after initial traction was released.

RESULTS

A total of 464 patients were identified, 26 (5.6%) with isolated microinstability, 183 (39.4%) with microinstability with FAI anatomy, and 255 (55.0%) with FAI. The concurrent diagnosis of microinstability was associated with decreased turns required to adequately distract the hip. Isolated microinstability patients required 6.9 turns (IQR 4.6-8.8) while those with instability plus FAI required 8.8 turns (IQR 6.5-11) and isolated FAI required 19.1 turns (IQR 15-22). Residual subluxation after removal of negative intra-articular pressure but before performing the hip arthroscopy was more commonly associated with instability, occurring in 84.6% of isolated instability and 86.9% of instability plus FAI as compared with 29.8% in the isolated FAI cohort.

CONCLUSION

A diagnosis of hip microinstability, with or without features of FAI, is associated with decreased axial traction required to distract the hip. These data support the use of intra-operative ease of distraction as a method of identifying patients with hip microinstability.

LEVEL OF EVIDENCE

Level III.

The traction force of the pulled limb in hip arthroscopic surgery is determined by stiffness coefficient which is significantly related to muscle volume

PURPOSE

To verify the relationship between muscle volume, lateral centre-edge angle (LCEA), alpha angle (AA), body mass index (BMI) and Beighton score with stiffness coefficient (SC). To analyse the difference of traction force at different physical states of hip joint capsule.

METHODS

Thirty-six patients who underwent hip arthroscopy operation were included. The volumes of some related muscles were measured in MRI images by 3D Slicer. We recorded and tested differences in traction force of five joint capsule physical states, including before (State 1) and after joint capsule puncture (State 2), after the establishment of anterolateral and mid-anterior approaches (State 3) and after incision of the joint capsule through these two approaches (States 4, 5). The correlation between muscle volume, BMI, LCEA, AA and SC was verified by Spearman test. Poisson regression was used to explain confounding variables.

RESULTS

The average force at State 1 was 531.8 N. There were significant differences in traction force between these five states (p < 0.001). There was a significant positive correlation between muscle volumes and SC (p < 0.001). BMI had no correlation with SC (n.s.). The preoperative LCEA of the affected side was correlated with SC (p = 0.043). AA and SC were not correlated (n.s.).

CONCLUSION

The physical states of the hip joint capsule affected traction force. Muscle volume rather than BMI is an ideal index to estimate preoperative traction force. LCEA affected traction force, whilst AA and Beighton score did not. Measuring the muscle volume can help estimate the most suitable traction force for the patient.

LEVELS OF EVIDENCE

IV.

Female Patients and Decreased Hip Capsular Thickness on Magnetic Resonance Imaging Associated With Increased Axial Distraction Distance on Examination Under Anesthesia: An In Vivo Study

PURPOSE

To investigate the relation of hip capsular thickness as measured on preoperative magnetic resonance imaging (MRI) and intraoperative hip joint axial distraction distance on an examination under anesthesia.

METHODS

A retrospective review of primary arthroscopic hip procedures performed between November 2018 and June 2021 was conducted. The inclusion criteria included a diagnosis of femoroacetabular impingement syndrome and preoperative radiographic imaging and MRI. Fluoroscopic images were obtained at 0 lb and 100 lb of axial traction force. Total distraction distance was calculated by comparing the initial joint space with the total joint space at 100 lb. Hip capsular thickness was measured on MRI. Analysis was conducted using multiple linear regression, independent-samples t tests, and Mann-Whitney U tests.

RESULTS

Eighty patients were included. Bivariable regression showed an association between an increased distraction distance and female sex (β = 4.303, R = 0.561, P < .001), as well as decreased anterior axial (β = -1.291, R = 0.365, P < .001) and superior coronal (β = -1.433, R = 0.501, P < .001) capsular thickness. Multivariable regression (R = 0.645) showed an association between an increased distraction distance and female sex (β = 3.175, P < .001), as well as decreased superior coronal capsular thickness (β = -0.764, P = .022). Independent-samples t tests showed that female patients had significantly decreased superior coronal capsular thickness (2.92 ± 1.14 mm vs 3.99 ± 1.15 mm, P < .001).

CONCLUSIONS

Female sex and decreased hip capsular thickness in the superior aspect of the coronal plane on magnetic resonance scans were found to be predictors of increased hip joint axial distraction distance on examination under anesthesia prior to hip arthroscopy, with anterior axial capsular thickness being a moderate predictor. Poor predictors of distraction distance were posterior axial and inferior coronal capsular thickness, age, body mass index, and lateral center-edge angle. Female patients were also found to have thinner hip capsules in the superior region, which may explain the association between female patients and increased distraction. These findings further characterize the relation between capsular thickness and hip laxity.

LEVEL OF EVIDENCE

Level IV, case series.

Female gender, decreased lateral center edge angle and a positive hyperextension-external rotation test are associated with ease of hip distractability at time of hip arthroscopy

PURPOSE

To identify factors associated with ease of hip distraction at the time of hip arthroscopy.

METHODS

A retrospective review of patients 17-50 years old undergoing hip arthroscopy with a single high-volume hip arthroscopist was performed from 2014 to 2020. Demographics, clinical history, examination, and imaging findings were collected. Distractibility was quantified using turns of fine traction (1 turn = 4 mm axial distraction) with the patient paralyzed on a fracture table with a well-padded perineal post Fine axial traction was applied after the patient's perineum contacted the post. Demographic and clinical predictors of ease of distractibility were analyzed with simple linear regression models. Significant predictors were subsequently added to a multivariable linear regression model, estimating the effect of each variable.

RESULTS

In total, 453 patients were included, with an average age of 31.6 years (± 9.2) and 45.9% females. In univariate analysis, gender, race, BMI, range of motion, hyperextension-external rotation (HEER) test, the abduction-extension-external rotation test, and lateral center edge angle (LCEA) were associated with the number of fine traction turns required to distract the hip. On multivariable analysis, lower LCEA (p = 0.002), female gender (p < 0.001), and a positive HEER test (p = 0.045) were associated with decreased turns required for adequate hip distraction.

CONCLUSION

Female gender, decreased LCEA, and a positive HEER test are associated with decreased axial traction required for adequate hip distraction at the time of hip arthroscopy. As ease of distractibility has been associated with hip microinstability, these findings may allow pre-operative identification of hip instability patients and aid in pre-operative counseling, risk stratification and capsular management planning.

LEVEL OF EVIDENCE

IV.

CLINICAL RELEVANCE

Preoperative identification of risk factors for ease of hip distraction may raise pre-surgical suspicion and, when coupled with other intraoperative findings, may aid in the diagnosis and management of hip microinstability.

Previous Arthroscopic Hip Surgery Increases Axial Distractibility Compared to the Native Contralateral Hip and May Suggest Instability

PURPOSE

To compare intraoperative hip joint distractibility between hips that previously underwent arthroscopic surgery and the contralateral hip with no history of surgical manipulation.

METHODS

Patients undergoing revision hip arthroscopy between April 2019 and December 2020, who previously underwent arthroscopic hip surgery for femoroacetabular impingement syndrome, were prospectively enrolled. Exclusion criteria were any contralateral hip surgery. Before instrumentation, fluoroscopic images of both hips were obtained at 25 lbs traction intervals up to 100 lbs. Total joint space was measured at each traction interval. Distraction was calculated as the difference between the baseline joint space and the total joint space at each subsequent traction interval. Wilcoxon signed ranks tests and McNemar tests were used to compare distraction between revision and native contralateral hips.

RESULTS

Forty-seven patients were included. Mean distraction of operative hips was significantly greater than mean distraction of nonoperative hips at traction intervals of 50 lbs (2.13 vs 1.04 mm, P = .002), 75 lbs (6.39 vs 3.70 mm, P < .001), and 100 lbs (8.24 vs 5.39, P < .001). Mean total joint space of operative hips was significantly greater than mean total joint space of nonoperative hips at traction intervals of 50 lbs (6.60 vs 5.39 mm, P < .001), 75 lbs (10.86 vs 8.05 mm, P < .001), and 100 lbs (12.73 vs 9.73, P < .001). A greater percentage of operative hips achieved all distraction thresholds, in 2-mm intervals up to 10-mm, at each traction interval.

CONCLUSIONS

In the majority of patients undergoing revision hip arthroscopy, previous arthroscopic hip surgery increases axial distractibility of the hip joint compared with the native contralateral hip at axial traction forces of 50-100 lbs. Increased axial distractibility following hip arthroscopy may be suggestive of hip instability and can be assessed on a stress examination with the patient under anesthesia.

LEVEL OF EVIDENCE

III, case-control study.

Sexual and urinary function post-surgical treatment of femoroacetabular impingement: experience from the FIRST trial and embedded cohort study

The goal of this study was to investigate the sexual and urinary function and any related complications in patients post-hip arthroscopy for the treatment of femoroacetabular impingement (FAI). Data from 214 patients enrolled in the FIRST trial and 110 patients enrolled in the trial’s embedded prospective cohort study (EPIC) were analyzed. EPIC patients either refused to participate in the trial or did not meet the FIRST eligibility criteria. Outcomes included the International Consultation on Continence Questionnaire (ICIQ) for males (ICIQ-MLUTS) and females (ICIQ-FLUTS) and the Female Sexual Function Index (FSFI) and International Index of Erectile Function (IIEF) administered before surgery and at 6 weeks and 12 months. Urinary and sexual function adverse events were recorded up to 24 months. Linear regression analyses were conducted to compare the osteochondroplasty and lavage groups in the FIRST trial and to evaluate age and traction time as prognostic factors among all patients. Longer traction time was associated with a small but statistically significant improvement in urinary voiding function in males at 6 weeks and 12 months (MD (95% CI) = 0.25 (0.12, 0.39), P &lt; 0.001 and 0.21 (0.07, 0.35), P = 0.004), respectively. Mean traction time was 43.7 (± 23.2) min for FIRST trial and 52.8 (± 15.2) min for EPIC cohort patients. Increasing age in male patients was associated with a decrease in urinary continence at 6 weeks (MD (95% CI) = 0.25 (−0.42, −0.09), P = 0.003). FIRST male patients who received osteochondroplasty improved significantly in sexual function at 12 months compared to males in the EPIC cohort (MD (95% CI) = 2.02 (0.31, 3.72), P = 0.020). There was an overall complication rate of 1.2% at 24 months [one urinary infection, two instances of erectile dysfunction (one transient and one ongoing at 24 months) and one reported transient numbness of tip of the penis]. Hip arthroscopy for the treatment of FAI has a low rate of sexual and urinary dysfunction and adverse events.

Joint Venting Prior to Hip Distraction Minimizes Traction Forces During Hip Arthroscopy

PURPOSE

This study evaluates the effect of venting on distraction of the hip during arthroscopy on a post-free traction table for fixed traction forces ranging from 0 to 100 pounds (lbs).

METHODS

Patients underwent surgery by the senior author (S.K.A.) between November 2018 and July 2019. Inclusion criteria were primary hip arthroscopy requiring central compartment access. Patients were positioned in 10-15° Trendelenburg on a post-free traction table. Prior to instrumentation, fluoroscopic images of the operated hip joint were taken at 25-lb intervals from 0 to 100 lbs of axial traction. Traction was released for 15 minutes. Venting with 20 mL of air was performed and fluoroscopic images were repeated at all traction intervals. Joint displacement was measured at all intervals. An unvented control group underwent the same axial traction protocol for comparison.

RESULTS

Sixty-one consecutive patients underwent study protocol. Fifty-eight hips in 57 patients were included. Thirty-two (55.2%) were female; mean age was 31 ± 13 years and mean body mass index was 25.7 ± 6.2. Paired samples analysis demonstrated mean differences in distraction distance prior to and after venting of 0.27, 2.60, 4.09, 4.54, and 2.31 mm at 0, 25, 50, 75, and 100 lbs of traction, which were significant (P < .001) at all traction intervals. Significantly more vented hips distracted at least 10 mm at 25-100 lbs traction (P ≤ .001). An unvented control group showed no significant differences between the first and second traction application.

CONCLUSIONS

Venting prior to applying traction on a post-free traction table increases the distraction distance achieved for a given traction force at multiple levels of traction in comparison to the pre-vented state. Our results suggest venting the hip joint prior to the application of traction may serve to reduce the maximal amount of traction required to safely instrument the hip arthroscopically.

LEVEL OF EVIDENCE

IV, case series.

Deep neuromuscular paralysis during hip arthroscopic surgery: influence on perineal tissue pressures and hip joint width

Pudendal nerve injuries are not an uncommon side effect of patient positioning on a traction table, and muscle relaxation has been suggested to mitigate this risk by reducing pressure on the perineum. A total of 40 patients scheduled for hip arthroscopic surgery under general anaesthesia were recruited. After induction of anaesthesia, pressures on the perineum were measured in 20 subjects by means of an ultra-thin pressure sensor mat wrapped around the perineal post. Perineal pressures were assessed after the induction of anaesthesia, after leg traction and after deep muscle relaxation. In 22 subjects, the hip joint width was measured radiographically at the same time points. Pressures on the perineum were high after traction (median maximum pressure 2540 g cm⁻²). Neuromuscular paralysis reduced perineal pressures only minimally, but significantly (−5 g cm⁻²; P = 0.007). Traction increased hip joint width significantly [mean 66 (12)%; P = 0.001) and muscle relaxation further increased joint width by a mean of 3.2 (0–20)% (P = 0.001). Muscle relaxation was more beneficial for male patients (joint width increase 6.8% versus 2.8%; P = 0.04), as well as patients in whom traction alone did not achieve sufficient joint width. Muscle relaxation reduced the perineal pressure during hip arthroscopic surgery by only a negligible amount. With regard to joint space, relaxation may be of highest benefit in male patients and/or patients in whom traction alone produces only a relatively small increase in joint width (trial registration: ANZCTR 12617000191392).

Stepwise Safe Access in Hip Arthroscopy in the Supine Position: Tips and Pearls From A to Z

Hip arthroscopy is rapidly growing as a treatment with good outcomes for pathologic conditions such as femoroacetabular impingement syndrome and labral tears. At the same time, it is one of the most technically challenging and demanding procedures in orthopaedics with a technically demanding skill. The first challenge is to safely access the joint, which requires accurate anatomical knowledge, a strong sense of spatial orientation, and repeated practice. Iatrogenic chondrolabral injury has been reported as the most common complication in hip arthroscopy and most frequently occurs during hip joint access. As such, basic foundations cannot be overstated. These complications can be minimized with adequate patient positioning, reproducible hip joint access techniques, and proper portals placement. Nonetheless, these three points are perhaps the greatest hurdles that orthopaedic surgeons face when entering the hip arthroscopy field. In this review, we outlined a stepwise approach for a safe access to hip arthroscopy.

The effects of venting and capsulotomy on traction force and hip distraction in hip arthroscopy

This study evaluated the effects of venting and capsulotomy on the ratio of normalized distraction distance to traction force, correlating this trend with patient demographic factors. A ratio was chosen to capture the total effect of each intervention on the hip joint. During primary hip arthroscopy, continuous traction force was recorded, and fluoroscopic images were acquired to measure joint distraction before and after the application of traction, venting and interportal capsulotomy. Distraction–traction force ratios were compared using a one-sided paired t-test. A linear regression model was used to determine the relationship between age, sex and body mass index and pre- and post-intervention distraction–traction force ratios. Seventy-two adult patients and 73 hips were included. There was an increase in hip distraction with a decrease in traction force post-venting and capsulotomy (both P’s <0.001). Mean normalized distraction distance increased 1.5% of femoral head size after venting and an additional 2.2% of femoral head size after capsulotomy. Mean traction force decreased 2.2% (14.7 N) after venting and 2.3% (15.3 N) after capsulotomy. Female sex significantly correlated with larger differences in both pre- and post-venting capsulotomy ratios. Venting and capsulotomy both independently improve the ratio of normalized distraction distance to traction force when performed in vivo. However, the effect sizes of each intervention are small and of questionable clinical significance. Specifically, when adequate distraction for safe surgical hip access cannot be obtained despite application of significant traction force, venting and capsulotomy after the application of traction may not afford substantial improvement.

Traction force for peroperative hip dislocation in hip arthroscopy

OBJECTIVES

Traction force widens the joint space during hip arthroscopy. It is unclear how much the traction force varies and if it is related to the joint space widening. Main goal of our study was to measure the amount of force needed to widen the hip joint. Second goal was to study the relation between this force and the amount of joint space widening.

METHODS

Traction force was measured in 27 patients (of whom 24 female, mean age 41) during arthroscopy. Measurements were performed before the procedure, after vacuum seal release and after capsulotomy. Joint space widening was measured with fluoroscopy and was calibrated. Friedman and Wilcoxon tests were used to measure differences in traction. The Spearman's rho correlation coefficient was used to identify a correlation in traction force and joint space widening. Regression analyses were used to identify relations between age, body mass index (BMI), hip degeneration and traction force.

RESULTS

The median traction force before arthroscopy was 714 N, lowered to 520 N after vacuum seal release and to 473 N after capsulotomy (p < 0.001). Median joint space widening was 8.8 mm. Spearmans' rho correlation between traction force and joint space widening was ‒0.13.

DISCUSSION

Median traction force of 714 N resulted in 8.8 mm of joint space widening. This traction force was significantly lowered by 200 N after release of the vacuum seal of the hip and 250 N after additional capsulotomy without loss of joint space narrowing. No significant relation was identified for age, BMI or progression of the Kellgren-Lawrence classification for hip degeneration and traction force. Netherlands Trial Registry number 8610.

Patient-Specific Parameters Associated With Traction in Primary and Revision Hip Arthroscopic Surgery

Background:

Distraction of the hip joint is a necessary step during hip arthroscopic surgery. The force of traction needed to distract the hip is not routinely measured, and little is known about which patient factors may influence this force.

Purpose:

To quantify the force of traction required for adequate distraction of the hip during arthroscopic surgery and explore the relationship between hip joint stiffness and patient-specific demographics, flexibility, and anatomy.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 101 patients (61 female) undergoing primary hip arthroscopic surgery were prospectively enrolled. A load cell attached to the traction boot continuously measured traction force. Fluoroscopic images were obtained before and after traction to measure joint displacement. The stiffness coefficient was calculated as the force of traction divided by joint displacement. Relationships between the stiffness coefficient and patient demographics and clinical parameters were investigated using a univariable regression model. The regression analysis was repeated separately by patient sex. Variables significant at P < .05 were included in a multivariable regression model.

Results:

The instantaneous peak force averaged 80 ± 18 kilogram-force (kgf), after which the force required to maintain distraction decreased to 57 ± 13 kgf. In univariable regression analysis, patient sex, alpha angle, hamstring flexibility, and Beighton hypermobility score were each correlated to stiffness. However, patient sex was the only significant variable in the multivariable regression model. Intrasex analysis demonstrated that increased hamstring flexibility correlated with decreased final holding stiffness in male patients and that higher Beighton scores correlated with decreased maximal stiffness in female patients.

Conclusion:

Male patients undergoing primary arthroscopic surgery have greater stiffness to hip distraction during arthroscopic surgery compared with female patients. In male patients, stiffness increased with decreasing hamstring flexibility. In female patients, increased Beighton scores corresponded to decreased stiffness. The presence of a labral tear was not correlated with stiffness to distraction. These data may be used to identify patients in whom a specific focus on capsular repair and/or plication may be warranted.

The effect of surgeon's learning curve: complications and outcome after hip arthroscopy

INTRODUCTION

The aim of the present study was to determine the incidence and type of complications during and after hip arthroscopy as well as the effect of the surgeon's learning curve on the occurrence of complications. We expect that the currently reported prevalence especially of minor complications is likely to be underreported in most retrospective series based on chart analysis.

MATERIALS AND METHODS

The study included all consecutive patients who underwent hip arthroscopy between 2006 and 2014 at a minimum follow-up of 6 weeks starting with the first patient undergoing hip arthroscopy at the institution. Patient outcome was evaluated using the WOMAC score, VAS for pain, SF-36 questionnaire and the hip-outcome score. Additionally, intra- and postoperative complications were recorded via a questionnaire and additional review of patient files.

RESULTS

We identified 529 patients who underwent hip arthroscopy between 2006 and 2014. Complete data could be gathered from 485 patients (91.7%). Major complications occurred in three patients (0.6%; fractures of the femoral neck requiring surgical treatment in one case). Minor complications that did not require further intervention were self-limiting postoperative temporary neurapraxia, hematoma, self-limiting dyspareunia, deep vein thrombosis and impaired wound healing, with hematoma and temporary paresthesia due to traction neurapraxia being the most common ones (22.5 and 16.4% respectively). The overall re-operation rate was 15.7% with conversion to total hip arthroplasty being the most common (11.9%).

CONCLUSIONS

The overall major complication rate was low and thus hip arthroscopy can be rated as a safe procedure. But minor complications such as hematoma and temporary paresthesia due to traction neurapraxia are common and currently underreported. Surgeons' learning curves show a reduction of major complications once 60 procedures per surgeon per year is surpassed.