Original Research Polyurethane Scaffold vs Fascia Lata Autograft for Hip Labral Reconstruction Comparison of Femoroacetabular Biomechanics Bruno Capurro,*†‡§k PhD, Marc Tey-Pons,†k PhD, Anna Carrera,§ PhD, Fernando Marqués-López,† PhD, Oliver Marı́n-Peña,k{ PhD, Raúl Torres-Eguı́a,k# MD, Joan Carles Monllau,† PhD, and Francisco Reina,§ PhD Investigation performed at Universitat Autònoma de Barcelona, Barcelona, Spain Background: The integrity of the acetabular labrum is critical in providing normal function and minimizing hip degeneration and is considered key for success in today’s hip preservation algorithm. Many advances have been made in labral repair and recon- struction to restore the suction seal. Purpose/Hypothesis: To compare the biomechanical effects of segmental labral reconstruction between the synthetic poly- urethane scaffold (PS) and fascia lata autograft (FLA). Our hypothesis was that reconstruction with a macroporous polyurethane implant and autograft reconstruction of fascia lata would normalize hip joint kinetics and restore the suction seal. Study Design: Controlled laboratory study. Methods: Ten cadaveric hips from 5 fresh-frozen pelvises underwent biomechanical testing with a dynamic intra-articular pressure measurement system under 3 conditions: (1) intact labrum, (2) reconstruction with PS after a 3-cm segmental labrectomy, then (3) reconstruction with FLA. Contact area, contact pressure, and peak force were evaluated in 4 positions: 90 of flexion in neutral, 90 of flexion plus internal rotation, 90 of flexion plus external rotation, and 20 of extension. A labral seal test was performed for both reconstruction techniques. The relative change from the intact condition (value ¼ 1) was determined for all conditions and positions. Results: PS restored contact area to at least 96% of intact (0.96; range, 0.96-0.98) in all 4 positions, and FLA restored contact area to at least 97% (0.97; range, 0.97-1.19). Contact pressure was restored to 1.08 (range, 1.08-1.11) with the PS and 1.08 (range, 1.08-1.10) with the FLA technique. Peak force returned to 1.02 (range, 1.02-1.05) with PS and 1.02 (range, 1.02-1.07) with FLA. No significant differences were found between the reconstruction techniques in contact area in any position (P > .06), with the exception that FLA presented greater contact area in flexion plus internal rotation as compared with PS (P ¼ .003). Suction seal was confirmed in 80% of PSs and 70% of FLAs (P ¼ .62). Conclusion: Segmental hip labral reconstruction using PS and FLA reapproximated femoroacetabular contact biomechanics close to the intact state. Clinical Relevance: These findings provide preclinical evidence supporting the use of a synthetic scaffold as an alternative to FLA and therefore avoiding donor site morbidity. Keywords: hip; labrum; reconstruction; polyurethane scaffold; autograft The acetabular labrum is critical in providing normal func- pressure that produces an audible sound and dislocation tion and minimizing hip degeneration and is considered key of the hip. If the seal is not maintained, no resistance to for success in today’s hip preservation algorithm. Although the distracting force is perceived, nor is the sound heard. tears were initially subject to debridement or excision,21 Many advances have been made in labral repair and recon- surgeons have come to understand the important role of the struction to restore the suction seal. labrum in stabilizing the hip and restoring the suction seal. The current gold standard for a hip labral tear is to Losing the seal (ie, vacuum) results in negative sealing repair it when possible. There are cases, however, where the tear is not amendable to repair or a revision is required The Orthopaedic Journal of Sports Medicine, 11(2), 23259671221150632 after a primary repair. In an attempt to preserve the hip DOI: 10.1177/23259671221150632 joint, the concept of labral reconstruction (or replacement) ª The Author(s) 2023 has become popular23 in recent years, with the aim of This open-access article is published and distributed under the Creative Commons Attribution - NonCommercial - No Derivatives License (https://creativecommons.org/ licenses/by-nc-nd/4.0/), which permits the noncommercial use, distribution, and reproduction of the article in any medium, provided the original author and source are credited. You may not alter, transform, or build upon this article without the permission of the Author(s). For article reuse guidelines, please visit SAGE’s website at http://www.sagepub.com/journals-permissions. 1 2 Capurro et al The Orthopaedic Journal of Sports Medicine minimizing joint degenerative changes that occur after an conservation of joint space (Tönnis grade <2). The exclu- irreparable or postlabral debridement injury (labrectomy). sion criteria were hips with a history of fracture or surgery, Arthroscopy is the preferred technique for labral recon- osteoarthritis history (Tönnis grade 2),8,10,20 or meta- struction, being 86% of the total techniques used2 and static bone disease. In addition, we excluded hips where resulting in superior functional results, lower reinterven- an undetectable severe osteochondral lesion was not indi- tion rates,39 and faster recovery as compared with an open cated on radiology and those where the size of the acetab- surgical dislocation procedure.6 ulum would not allow proper positioning of the sensor. The indications for labral reconstruction are rupture of Two pelvic specimens (4 hips) presented with severe osteo- the labral seal, tears or labral lesions that are not amend- chondral damage on direct inspection and were therefore able to repair (eg, insufficient labral size, degenerative excluded. Another pelvis (2 hips) was too small for adequate labrum, damaged, surgically debrided, calcified, flattened, insertion of the sensors. We used 3 pelvises (6 hips) in a pilot defibrillated, or nonviable), and failed prior surgical repair study to test the calibration and sensor positioning and to in young active patients.3,5,16 Many autograft and allograft refine the reconstruction technique and biomechanical work- options now exist for labral reconstruction, including ilioti- flow. This left 5 pelvises (10 hips) remaining for study testing. bial band (fascia lata), semitendinosus, indirect head of the The pelvic specimens were handled following a previ- rectus femoris tendon, and gracilis. The most used auto- ously described protocol 25,38 ; however, they were not graft for reconstruction is fascia lata (iliotibial band).3,5 divided into separate hips but were kept intact. The speci- As an alternative to using human tissue, biodegradable mens were defrosted at room temperature for 12 hours; synthetic polyurethane scaffolds (PSs) were developed then, a systematic dissection was performed by eliminating >15 years ago to restore the meniscus, with successful all musculature and soft tissue and keeping the ligament results clinically.7,11,14,36 In this study, we aimed to compare capsule complex untouched. They were refrozen and the effects of labral reconstruction using a macroporous PS thawed only on the day of biomechanical testing. At the vs a fascia lata autograft (FLA) on the contact area, contact conclusion of the testing, the specimens were frozen a third pressure, and peak force of the articular cartilage as well as time using the same protocol in case a test needed to be on the hip suction seal. We hypothesized that macroporous repeated. None of the tests required repeating; therefore, PS reconstruction and FLA reconstruction would normalize the specimens were not thawed a third time. hip joint kinetics and restore the suction seal. Testing Procedure METHODS The complete pelvic specimens were fixed in an anatomic Specimens position on a biomechanical test bench. This bench allows for angular control in the 3 axes of joint mobility. In the Ethics approval was obtained for the study protocol. absence of servomotors for movement control, maximum Twenty-two adult human hip specimens (11 complete pel- mobility for each specimen can be achieved. The design and vises including the proximal third of the femur) were methodology have been described.22,35 obtained from the donation program of the local university This testing protocol has also been described.12 Testing in accordance with the legal and ethical procedures of was carried out in 3 clinical situations for each specimen: human donation programs. The specimens were admitted (1) with the acetabular labrum intact, (2) after a 3-cm-long consecutively, with anonymity maintained and sex and age labrectomy and labral reconstruction with a polyurethane registered at the time of death. implant, and (3) after labral reconstruction with a labral The inclusion criteria were hips with intact acetabular FLA. During the preparation of each test and when the labrum, in which fluoroscopy confirmed normal anatomy specimen was not being tested, the labral surface and car- and no femoroacetabular impingement or impairment of tilage were kept lubricated with a gauze with normal saline the femoral head (Wiberg angle between 25 and 40 and solution. At the end of each test, both surfaces were lubri- absence of alterations in femoral head sphericity) and cated with cadaveric fat to avoid dehydration. *Address correspondence to Bruno Capurro Soler, PhD, Department of Orthopaedic Surgery and Traumatology, Hospital del Mar, Passeig Marı́tim de la Barceloneta, 25, 08003, Barcelona, Spain (email: doctor.capurro@gmail.com) (Twitter: @DrBrunoCapurro). † Department of Orthopaedic Surgery and Traumatology, Hospital del Mar, Universitat Autònoma de Barcelona, Barcelona, Spain. ‡ Department of Orthopaedic Surgery and Sport Traumatology, ReSport Clinic, Barcelona, Spain. § Clinical Anatomy, Embryology and Neuroscience Research Group, Medical Sciences Department, Faculty of Medicine, University of Girona, Girona, Spain. k Grupo Ibérico de Cirugı́a de Preservación de Cadera, Portugal and Spain. { Department of Orthopaedic Surgery and Traumatology, Hospital Infanta Leonor, Madrid, Spain. # Department of Orthopaedic Surgery and Traumatology, Clı́nica Cemtro, Madrid, Spain. Final revision submitted September 29, 2022; accepted October 21, 2022. The authors have declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto. Ethical approval for this study was obtained from Hospital Universitari de Girona Doctor Josep Trueta (No. 2018/8109/I). The Orthopaedic Journal of Sports Medicine Polyurethane Scaffold vs Fascia Lata Autograft 3 Intact Condition. A wide 360 capsulotomy was per- reproduced for each pelvic specimen. The dynamic study formed on each specimen to 2 mm of the acetabular rim, began from the anatomic position in extension, rotation, and the round ligament was sectioned to allow for insertion and neutral abduction, and progressive flexion was per- of the dynamic pressure sensors in a semicircular design formed to 90 . The joint was then brought to maximum (model 4400 N; Tekscan). The sensors, which were designed internal rotation (IR), followed by maximum external rota- to cover the entire chondral surface of the hip,29 were tion (ER) and back to neutral, finishing with an excursion attached to the capsule and labrum with a 3-point capsular in extension of 20 . The mean of 3 consecutive examinations suture (silk 2/0) to achieve a static position during testing; was used for each measurement. The movement was car- after each reconstruction was performed, the sensor was ried out manually, with each position timed and documen- reinserted at the same place marked with the 3 capsular ted. Throughout the study, a constant force of 50 N was suture points to allow reproducible measurements. applied with the dynamometer, with a variation of ±5 N. A dynamometer was used to ensure that stable pressure Each cycle lasted 30 seconds (±10%). If greater variations in was maintained throughout the study for all specimens strength or duration occurred, they were discarded, and the (Digital Force Gauge SF-500; Besland). cycle was repeated. Each test for the study was repeated 3 Polyurethane Scaffold. Although normally performed times, and the mean of the results was used. arthroscopically, an open procedure was used for this The contact area, contact pressure, and peak force values study. After the testing with intact native labrum was com- were normalized as the relative change from the intact con- pleted, the pressure sensors were detached from the cap- dition (value ¼ 1). This was necessary, as hips were differ- sule, which was retracted laterally. A longitudinal labral ent sizes and adaptation of the sensor may have been cut 3 cm long in the anterolateral zone was performed with influenced by that difference. a No. 10 scalpel, leaving a 2-mm lateral margin (labrect- To assess the participation of each area of the acetabular omy). Reconstruction was then carried out as previously surface, an analysis of the data was carried out in the fol- described12 with insertion of a biodegradable synthetic PS lowing 4 positions: 90 of flexion in neutral, maximum IR at (Actifit; Orteq) (Figure 1). This implant was modified for 90 of flexion, maximum ER at 90 of flexion, and extension the hip, is highly porous, and is composed of aliphatic poly- at 20 of neutral rotation. urethane. The scaffold was trimmed to a thickness of 8 mm and a length of 3 cm to fit the defect; three 5-mm anchors Statistical Analysis (Wedge Anchor II, No. 2 Force Fiber; Stryker) were placed every 7 mm in the middle to secure the implant; and 1 side- The normalized contact area, contact pressure, and peak to-side suture (high-resistance suture, Force Fiber; Stry- force values were compared between conditions (intact vs ker) was used to attach the labral remnant at each end. PS, intact vs FLA, PS vs FLA) at each of the 4 positions. The sensor was reattached to the capsule in the same place, Because multiple measurements were taken per specimen, and the specimen was repositioned on the bench. Because of normalized values were modeled using a repeated mea- the quality of the bone for specimen 8, an extra anchor was sures analysis of variance to account for potential correla- used in the middle of the scaffold. tion within each specimen. The least squares means and Fascia Lata Autograft. After testing with the PS was 95% confidence intervals are reported with a P value that complete, the sensors and the implant were removed. reflects the test: H0 (mean ¼ 1) vs H1 (mean 6¼ 1). Statistical Reconstruction with the FLA was performed according to analyses were performed using SAS Version 9.4 (SAS the technique of Lee et al,22 tubularizing and trimming it to Institute). a thickness between 6 and 7 mm and a length of 3 cm (Figure 1) and securing the graft with 1 continuous Vicryl 3.0 suture (Ethicon). The sensors were then reinserted. RESULTS Suction Seal Testing. The suction seal was tested accord- ing to the methods of Suppauksorn et al,33 which is per- Contact Area formed with the hip in a neutral anatomic position. After the capsulotomy, a section of the round ligament of the PS reconstruction restored the contact area to normal in all femoral head was rearticulated, and an axial distraction positions, with an overall recovery 96% (normalized force was applied and rated qualitatively if the seal was range, 0.96-0.98) and with no statistically significant differ- maintained. The suction seal was tested in the intact ences as compared with the intact labrum. When compared labrum on all specimens to confirm that it was present. It with the intact condition, the contact area was restored to was performed again after reconstruction with PS and after 0.96 (95% CI, 0.93-1.00; P ¼ .061) in flexion, 0.98 (95% CI, reconstruction with FLA. All labral sealing tests were per- 0.94-1.01; P ¼ .187) in flexion þ IR, 0.98 (95% CI, 0.94-1.02; formed by the same investigator (B.C.). P ¼ .243) in flexion þ ER, and 0.97 (95% CI, 0.93-1.00; P ¼ .076) in extension (Figure 2). Data Collection FLA reconstruction restored the contact area to at least 97% of intact. When compared with the intact condition, The contact area (cm2), contact pressure (kPa/cm2), and no significant difference was found in flexion (0.97; 95% peak force (kPa) of the acetabular cartilage were measured CI, 0.95-0.995; P ¼ .062), flexion þ ER (0.98; 95% CI, after the introduction of the femoral head into the acetab- 0.934-1.02; P ¼ .148), or extension (0.98; 95% CI, 0.95- ular cavity. The same sequence of movements was 1.01; P ¼ .147). The position of flexion þ IR, though, was 4 Capurro et al The Orthopaedic Journal of Sports Medicine Figure 1. (a) Polyurethane scaffold and fascia lata autograft. Reconstruction with (b) polyurethane scaffold and (c) fascia lata autograft. (b, c) On specimen 4 (left side), there are 3 anchors and 2 side-to-side translabral sutures. significantly different (1.19; 95% CI, 1.07-1.31; P ¼ .006) (95% CI, 1.00-1.17; P ¼ .05) in extension, with some values (Figure 2). significantly different vs intact (Figure 3). Comparing the contact area between reconstruction with When the contact pressure was compared between PS the macroporous polyurethane implant and FLA revealed and FLA, no significant difference was found in any posi- no differences in any of the positions of the joint range tion of the joint range (P > .7). (P > .6) except in flexion þ IR, where FLA presented greater contact area than PS (P ¼ .003). Peak Force Comparing peak force between intact labrum and PS, we Contact Pressure observed a recovery >95% of the peak force after the lab- rectomy, with no statistically significant differences found. When the contact pressure was compared between the In flexion, it was restored to 1.05 (95% CI, 0.99-1.11; intact labrum and both reconstruction techniques (PS and P ¼ .07); in flexion þ IR, 1.03 (95% CI, 0.99-1.10; P ¼ .20); FLA) after labrectomy, it was nearly restored to the intact in flexion þ ER, 1.02 (95% CI, 0.99-1.05; P ¼ .26); and in labrum in all movements of the analyzed joint range, extension, 1.04 (95% CI, 1.00-1.08; P ¼ .07) (Figure 4). although some positions were significantly different. For In the comparison of peak force between intact labrum the PS reconstruction in flexion, the contact pressure was and FLA reconstruction, we observed a recovery >98.5% of restored to 1.11 (95% CI, 1.04-1.18; P ¼ .003), flexion þ IR peak force. No differences were found in flexion þ IR (1.04; to 1.08 (95% CI, 1.00-1.14; P ¼ .008), flexion þ ER to 1.11 95% CI, 0.96-1.12; P ¼ .391) or extension (1.04; 95% CI, (95% CI, 1.04-1.18; P ¼ .0004), and extension to 1.12 (95% 0.99-1.09; P ¼ .109); however, a significant increase was CI, 1.05-1.19; P ¼ .02) (Figure 3). observed in flexion (1.07; 95% CI, 1.04-1.11; P ¼ .002) and For the FLA reconstruction, contact pressure was flexion þ ER (1.07; 95% CI, 1.03-1.11; P ¼ .008) (Figure 4). restored to 1.1 (95% CI, 1.04-1.16; P ¼ .002) in flexion, Comparison of peak force between reconstruction with 1.08 (95% CI, 1.03-1.13; P ¼ .005) in flexion þ IR, 1.11 PS and FLA found no differences in any position in the joint (95% CI, 1.04-1.16; P ¼ .002) in flexion þ IR, and 1.11 range (P > .09). The Orthopaedic Journal of Sports Medicine Polyurethane Scaffold vs Fascia Lata Autograft 5 Figure 2. Contact areas for the intact, PS, and FLA conditions: (a-d) flexion, flexion þ internal rotation (FLA vs intact, P ¼ .006), flexion þ external rotation, and extension. X, mean; horizontal line, median; top and bottom of box, first and third quartiles; whiskers, range; dots, outliers. *P < .01 vs intact. FLA, fascia lata autograft; PS, polyurethane scaffold. Figure 3. Contact pressure for the intact, PS, and FLA conditions: (a-d) flexion (PS vs intact, P ¼ .003; FLA vs intact, P ¼ .002), flexion þ internal rotation (PS vs intact, P ¼ .008; FLA vs intact, P ¼ .005), flexion þ external rotation (PS vs intact, P ¼ .0004; FLA vs intact, P ¼ .002), and extension (PS vs intact, P ¼ .005; FLA vs intact, P ¼ .05). X, mean; horizontal line, median; top and bottom of box, first and third quartiles; whiskers, range; dots, outliers. FLA, fascia lata autograft; PS, polyurethane scaffold. Suction Seal Testing DISCUSSION Labral sealing was confirmed in 100% of the intact labral The most important finding of this study is that reconstruc- specimens. After reconstruction with the macroporous tion with the macroporous polyurethane implant and FLA polyurethane implant, 80% of cases recovered labral seal- restored the contact area, contact pressures, and peak force ing (P < .01), and after reconstruction with the fascia auto- stresses to almost normal levels without differences graft, 70% (P < .01) were recovered. No statistically between the types of reconstruction techniques in any joint significant differences were observed in the labral sealing motion analyzed (P > .05), with the exception of contact test between the PS and FLA (P ¼ .06). area in flexion and IR. 6 Capurro et al The Orthopaedic Journal of Sports Medicine Figure 4. Peak force for the intact, PS, and FLA conditions: (a-d) flexion (FLA vs intact, P ¼ .002), flexion þ internal rotation, flexion þ external rotation (FLA vs intact: P ¼ .008), and extension. X, mean; horizontal line, median; top and bottom of box, first and third quartiles; whiskers, range; dots, outliers. FLA, fascia lata autograft; PS, polyurethane scaffold. The results show that the PS could be considered equally (evidence levels 3 and 4) and 402 patients. It is the best efficient in terms of its ability to reestablish the joint kinet- current evidence available on indications, types of grafts ics of the hip, although FLA is one of the most used and used, and results between 1 and 12 years of follow-up. The studied in clinical practice with good clinical authors concluded that when labral insufficiency or other results.7,11,14,36 The major advantages of autografts include conditions not amenable to repair are encountered, arthro- the maintenance of patient biology, the lack of disease scopic acetabular labral reconstruction with autografts transmission, and the ready availability and lower cost.23 results in significant improvement, based on short- and Although early reconstruction techniques favored the use midterm self-reported outcomes in young patients without of autograft, it is not without its complications. Ayeni et al3 moderate or advanced osteoarthritis of the hip. reported that graft harvesting is not a benign procedure but The polyurethane implant used in this study is an off- comes with the disadvantages of pain and donor site mor- the-shelf, readily available scaffold that has several advan- bidity. They suggested that when labral reconstruction is tages over autografts and allografts. It is easy to maneuver, being considered, other options should be evaluated as they provide advantages by overcoming the associated harvest- being of a strong consistency; it also has faster operative ing and donor site challenges of autografts. In an early times, no donor site morbidity, and reduced infection rates study on anterior cruciate ligament reconstruction using and disease transmission; finally, it retains its sutures the FLA, Bak et al4 reported that 8% of patients complained until integrated with the surrounding tissue.34 Because of of swelling and pain laterally on the thigh after harvest of its triangular shape, it is closer to the shape of the labrum an FLA and 20% expressed slight dissatisfaction with the as compared with the tubularized FLA.34 It has been used cosmetic appearance of the lateral thigh herniation. with great success in the knee as a meniscal replace- Another limitation to the use of autografts is reduced ment,29,36,37 and no inflammatory response of the implant survival time. Philippon et al26 observed 70% survival at in the knee has been reported up to 10 years.13,28,36,37 The 5 years and only 61% at 10 years with a mean survival time implant was customized to fit the hip for this study and a of 9 years with total hip arthroplasty as the endpoint. Nine previously published study by Tey-Pons et al.12,34 percent had a revision while 27% were revised to a total hip In our study, macroporous polyurethane implant recon- arthroplasty. Survival times for the PS scaffold in the knee struction and the FLA managed to increase the contact have been reported as 89% at 5 years 36 and 80% at area after labrectomy and normalize that parameter rela- 10 years.28 tive to intact labrum, reestablishing the contact area and The first published article on labral reconstruction was normalizing intra-articular stress. The exception was in in 2009 and described a technique using the ligamentum flexion and IR for the FLA where the increase was main- teres capitis.31 Since then, more graft sources and recon- tained. Since this is an impingement position, this might structive techniques have evolved.23 Bessa et al5 published suggest some issues in the future. a recent review analyzing the current state of labral recon- These findings are consistent with the cadaver study by struction. This systematic review included 7 studies Philippon et al 27 showing that labral reconstruction The Orthopaedic Journal of Sports Medicine Polyurethane Scaffold vs Fascia Lata Autograft 7 produced improvements in hip joint contact area and con- Limitations tact pressure as compared with labral resection. One of the main functions of the labrum is to distribute There are several limitations to the study. Although the pressures in the femoroacetabular joint.24 Biomechanical sample size was initially 22 specimens, 4 were used for trial studies have shown that an intact labrum allows direct cases and 2 were not large enough to accommodate the pressure to be evenly distributed within that joint.15 In this sensors. This left 10 specimens for our study. Most biome- study, intra-articular contact pressure was restored to close chanical cadaver studies, however, have used between 5 to normal with both reconstruction techniques, although and 10 specimens.1,32,33,35 The sensors in this study were the positions were still significant. It is unknown at this designed to be used in the hip but require a wide capsulot- time what the effects of this finding would be. Also, when omy to be inserted. Although it may affect the distribution compared with reconstructed joints that show a smooth and of the loads, we did not consider it a major limitation since homogeneous morphology of cartilage surfaces, postopera- we compared 3 clinical situations all in the same scenario. tive implants have histological, compression, and traction Cadaver specimens do not remain in the same condition as characteristics similar to those of native labrum. When hips in the surgical setting. We kept the specimens lubri- faced with irreparable labral injury, labral reconstruction cated with saline and cadaveric fat to preserve them as improves the distribution of intra-articular loads. Shi much as possible, although the measured pressures may et al30 concluded that the development of osteoarthritis can differ from those in the surgical situation. All conditions and positions were subject to this limitation. Although the be attenuated after labral reconstruction, contributing to polyurethane implant used in this study was developed for homeostasis of the hip joint. meniscal reconstruction, it is largely unknown how it will It is important to consider not only contact pressure but act in the hip. Yet, Tey-Pons et al34 observed good clinical also the peak force applied to the intra-articular surface. outcomes in their small study with no progression to oste- There is a relationship between increased stress forces and oarthritis using the same implant as used in this study. Its damage to the chondral surface caused by an increase of triangular shape does allow for good insertion at the base of these stresses, and it is considered an independent risk the triangle and correct apposition on the femoral head. factor of osteoarthritis.17 Areas of cartilage exposed to Future animal and clinical studies are planned to assess higher loads may have an increased risk of damage and (1) the ability of the scaffold to integrate into the subchon- reduced ability to effectively distribute loads during move- dral bone and (2) the degree of revascularization from the ment.18 Intense and acute or chronic impact where surfaces synovial membrane, thereby allowing it to generate new are subjected to a continuous excessive load can lead to tissue similar to the labrum, restore the native biomechan- degradation of the joint cartilage. We showed that recon- ics of the hip joint, and potentially slow the progression to struction with macroporous polyurethane implant and FLA osteoarthritis. managed to normalize peak force when compared with the intact labrum. This could add to the finding that labral reconstruction might not completely normalize the contact CONCLUSION pressure to the intact state; yet, if it manages to restore the peak forces, it could consequently decrease elevated tissue Reconstruction of a partial labrectomy with a synthetic deformation and shear forces that produce fibrillation and macroporous PS and FLA restores the joint kinetics of the chondral delamination,9 thereby reducing osteoarthritis hip to similar values as the intact labrum. Of 12 assess- progression.30 An exception should be mentioned for peak ments, 11 showed no difference between the techniques. force in FLA reconstruction in flexion plus ER and flexion It appears biomechanically that a synthetic scaffold is a where the joint capsule being the main stabilizer is likely to suitable alternative to a FLA for reconstruction the hip. have more impact with the acetabular labrum playing a secondary role.19 It is unknown at this time what the long-term consequences would be. ACKNOWLEDGMENT In our study, we performed the same labral sealing test as described by Suppauksorn et al.33 Our results show that The authors acknowledge the technicians Miriam Hidalgo labral sealing after a wide capsulotomy was maintained in and Marçal Asso for their invaluable work in the anatomy- 100% of the intact labral specimens and was reestablished biomechanical laboratory and Dr Eduard Tornero for his in 80% of specimens after reconstruction with the PS and support in the statistical analysis. 70% reconstructed with the FLA. Suppauksorn et al reported their results after a total labrectomy at 270 and REFERENCES reconstruction using an iliotibial band allograft. In our study, we analyzed the reconstruction of a 3-cm anterosu- 1. Afoke NY, Byers PD, Hutton WC. Contact pressures in the human hip perior partial labrectomy, which could explain the differ- joint. J Bone Joint Surg Br. 1987;69(4):536-541. ence between our 80% recovery of the seal and their 22.5% 2. 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