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Abstract

Background:

Acetabular cartilage delamination (ACD) is a common femoroacetabular impingement (FAI) complication that can cause progressive osteoarthritis if untreated. The early diagnosis and appropriate treatment are crucial to prevent irreversible joint damage. However, its radiological diagnosis is challenging, and there is no clear treatment algorithm.

Purpose:

To provide an up-to-date overview of the diagnosis and treatment of ACD in patients with FAI.

Study Design:

Scoping review; Level of evidence, 4.

Methods:

A comprehensive search of the PubMed database was conducted using relevant search terms related to FAI and ACD. Articles that met the inclusion criteria and focused on the diagnosis and treatment of ACD were selected and reviewed.

Results:

A systematic search of the PubMed database was performed using the keywords “femoroacetabular impingement” and “delamination.” The initial search yielded 42 articles. After removal of 12 duplicates, 30 articles underwent full screening. Four review articles, 1 case report, and 9 irrelevant studies were subsequently excluded. Ultimately, 16 studies met the inclusion criteria and were analyzed for information regarding the diagnosis and treatment of ACD in patients with FAI.

Diagnostic imaging modalities such as magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) demonstrated potential in detecting ACD in patients with FAI; however, their accuracy varied across studies. MRI demonstrated satisfactory sensitivity and specificity alongside moderate interobserver reliability in detecting ACD. However, MRA showed inconsistent results, with some studies reporting poor sensitivity due to limited joint distensibility. Treatment options for ACD included nonoperative management, arthroscopic debridement, microfracture, fibrin adhesive, microfragmented adipose tissue transplantation (MATT), and chitosan-based scaffolds. Studies have reported favorable outcomes with the various surgical techniques; nevertheless, long-term follow-up data are limited.

Conclusion:

Advanced imaging techniques are valuable tools for diagnosing ACD in patients with FAI; however, challenges in terms of achieving optimal sensitivity and specificity persist. Surgical interventions, including arthroscopic techniques and tissue augmentation with fibrin adhesive, MATT, and chitosan-based scaffolds, have potential in restoring cartilage integrity and improving clinical outcomes. Further studies should refine the diagnostic criteria and establish optimal treatment algorithms for ACD in patients with FAI.

Keywords

acetabular cartilage delamination femoroacetabular impingement early diagnosis advanced imaging techniques

Femoroacetabular impingement (FAI) can cause labral tears and cartilage damage through joint incongruence or aberrant joint loading patterns, subsequently precipitating morphological alteration of either the acetabulum or femur.^4,6 Furthermore, the results of patients who underwent surgery for FAI have been excellent; however, the failure rate may be high when acetabular cartilage delamination (ACD) is present.^10,28,36,45

ACD is the separation of the cartilage layer from the underlying subchondral bone, and the reported incidence of ACD in FAI ranges from 30% to 52% according to previous studies.^4,16,37 This is primarily caused by impingement resulting from intrusion of the cam lesion, which increases the shear forces in the hip joint. If impingement continues, cartilage delamination increases and eventually causes full-thickness defects and intra-articular loose bodies by detaching from the adjacent cartilage. In addition, increased stress and strain in the adjacent cartilage result in continued cartilage degeneration, which eventually predisposes patients to progressive osteoarthritis.^4,8,9 Therefore, early ACD detection and proper treatment are needed. Prosthetic hip replacement rather than joint-preserving surgery should be considered in patients with advanced cartilage delamination.¹⁴ Therefore, accurate preoperative assessment of the acetabular cartilage is crucial for choosing the appropriate treatment plan.

The treatment of ACD in patients with FAI typically involves addressing the underlying impingement and repairing or restoring the damaged cartilage. Nonoperative management, including physical therapy and activity modification, is recommended for mild cases. However, surgical intervention may be required in severe cases and arthroscopic surgery is the most common surgical approach for the treatment of FAI and associated ACD.

Recent studies have indicated that certain patient characteristics are associated with a higher risk of developing ACD. Particularly, male sex, cam-type morphology, increased alpha angle, and higher body mass index are significant risk factors.^1,10 These features may exacerbate shear forces at the chondrolabral junction, contributing to delamination and further cartilage deterioration.

However, ACD was discovered primarily through hip arthroscopy (Figure 1), and diagnosing delamination radiologically is an arduous task.

Figure 1.

Arthroscopic visualization of acetabular cartilage delamination in a patient with femoroacetabular impingement. (A) Arthroscopic probing reveals a cartilage flap separated from the underlying subchondral bone, indicating acetabular cartilage delamination. (B) After elevation of the delaminated flap, unstable cartilage is clearly visible with exposure of the subchondral bone.

The hip joint is highly congruent, resulting in minimal volume between opposing cartilage surfaces, and the articular contact of the hip joint is too close.^7,40 There is still no clear treatment algorithm to address this entity. Recently, improved methods for diagnosing ACD in patients with FAI before surgery have been reported.^19,32,37 Moreover, the results of cartilage restoration techniques have improved with the enhancement in hip arthroscopy.¹² Therefore, in this systematic review, we aimed to provide up-to-date knowledge on the diagnosis and treatment of ACD in patients with FAI.

Methods

A thorough online search of the PubMed database was performed using the following search terms: “femoroacetabular impingement” and “delamination.” Articles published from inception until June 24, 2023, were screened. Furthermore, studies were filtered according to the following inclusion criterion: information regarding diagnosis and treatment. Sixteen articles were included and reviewed (Figure 2).

Figure 2.

Flow diagram of study selection in the systematic review.

Results

Diagnosis

Identifying ACD early in patients with FAI using imaging methods such as magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) is very important. Treating them accordingly before the irreversible progression of osteoarthritis occurs is very important. However, there is no consensus on the accuracy of MRI and MRA in detecting ACD in patients with FAI. Therefore, preoperative diagnosis of ACD remains a challenging task.

Magnetic Resonance Imaging

MRI is relatively good in diagnosing ACD; however, its performance differs from study to study, with moderate interobserver reproducibility. MRI signs for diagnosing ACD have been defined in accordance with a previous study by Pfirrmann et al.³⁷ Images were assessed for signs of delamination, including the presence of a linear area of bright signal intensity along the acetabular subchondral bone and an area of darker tissue on the surface of the acetabular cartilage (Figure 3).

Figure 3.

Magnetic resonance imaging findings of acetabular cartilage delamination in patients with femoroacetabular impingement. (A) Sagittal T2-weighted fat-suppressed image showing a high-signal linear cleft (arrow) along the acetabular subchondral bone, consistent with cartilage delamination. (B) Radial image showing a high-signal intensity cartilage flap (arrow) overlying the acetabular dome, indicating delaminated acetabular cartilage.

Neumann et al³⁵ reported that 3 independent radiologists diagnosed the aforementioned signs using nonarthrographic 3-T MRI before surgery and confirmed them through arthroscopy during arthroscopic hip surgery. The interface between the acetabular cartilage and subchondral bone was evaluated, and the characteristics of the delaminated acetabular cartilage were verified using a probe during arthroscopy. Furthermore, when pathological buckling of the acetabular cartilage (carpet or wave sign) was observed, the patient was said to have ACD. The mean sensitivity and specificity of the 3 evaluators were 73.0% and 71.0%, respectively. In the analysis of patients with only FAI, the sensitivity and specificity were 77.7% and 66.7%, respectively. Interobserver reliability showed moderate agreement across the raters (kappa coefficient [k] = 0.450). MRI showed satisfactory sensitivity and specificity along with moderate interobserver reliability in this study; therefore, it was helpful in the preoperative identification of ACD.

Gao et al¹⁹ reported that the results of 3-T MRI in diagnosing ACD were better than those of 1.5-T MRA. They retrospectively evaluated patients who underwent arthroscopic surgery for the diagnosis of FAI. All patients underwent preoperative imaging using 3-T MRI, and ACD was evaluated by 2 raters using these scans. Of the 233 patients, ACD was confirmed in 101 (43.3%) during hip arthroscopy. The intraobserver reliability of both observers in detecting ACD using 3-T MRI scans was almost perfect (observer 1: k = 0.909 [95% CI, 0.854-0.964]; observer 2: k = 0.937 [95% CI, 0.890-0.984]), and the interobserver reliability between the observers (k = 0.801 [95% CI, 0.723-0.879]) was substantial. The overall sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of preoperative MRI for detecting ACD were 83.7%, 82%, 74.2%, and 89.1%, respectively. Therefore, based on the findings of this study, it can be concluded that 3-T MRI is sufficiently reliable to diagnose ACD in patients with FAI and could be reliable for diagnosing ACD preoperatively.

Linda et al²⁹ reported that 3-T MRI is a highly accurate technique for evaluating ACD in patients with clinically suspected hip FAI. High-resolution MRI scans were evaluated by 2 musculoskeletal radiologists, who were blinded to the arthroscopic findings, to determine the presence of articular cartilage lesions. In total, 42 consecutive patients with suspected FAI who underwent nonarthrographic 3-T MRI and hip arthroscopy were reviewed. Of the 36 patients (36/42, 86%) identified as having acetabular cartilaginous pathology on MRI, 26 (26/36, 72%) demonstrated articular cartilage delamination. MR and arthroscopic grading of the acetabular articular cartilage revealed discordant results in 10 cases.

According to a recent study,³⁴ the use of MRA carries the risk of masking the flap of the delaminated cartilage, which may decrease its sensitivity. The space between the delaminated cartilage and adjacent bone may not communicate with the joint space; consequently, intra-articularly administered contrast media may not enter this space. Moreover, intra-articularly administered contrast media can increase the pressure within the joint and push the flap back against the bone. Therefore, the use of nonarthrographic MRI may be advantageous in detecting acetabular delamination as it does require injecting additional fluid, which does not increase the pressure within the joint space.

One study³⁹ revealed that quantitative MR-based measurements are effective tools for diagnosing ACD. Voxel-based relaxometry enables examination of the local distribution of T1ρ and T2 mapping and has recently been used to assess joint cartilage composition. Relatively novel quantitative compositional imaging techniques have been introduced with regard to osteoarthritis to detect the early signs of articular cartilage deterioration. These techniques can aid in assessing compositional changes in collagen fibrils or regional changes in proteoglycans within the extracellular matrix.²⁷ In addition, the aforementioned changes can be observed in patients with FAI. Because of the altered acetabular cartilage composition in these patients, they exhibit significantly greater global (T1p and T2) relaxation times within the acetabulum than do healthy controls.^15,37 Moreover, assessment of T1p and T2 radial heterogeneity within the anterior superior acetabular cartilage detects articular cartilage delamination more precisely than global T1p and T2 mapping performed on patients with FAI exhibiting arthroscopic validation. Therefore, these imaging techniques are very promising for improving the detection of ACD in patients with FAI and could serve as tools for determining early markers of delamination, despite further studies being needed. However, time-consuming MR data registration and equation analysis of these techniques must be considered with respect to their usefulness and benefits for application in a clinical setting.

Magnetic Resonance Arthrography

MRA is considered a reliable diagnostic tool for detecting osteonecrosis³³; however, for acetabular labral tears²⁶ and meniscal tears of the knee,³⁰ its diagnostic strength with regard to ACD lesions remains uncertain.^13,40 The findings and diagnostic performance of MRA in treating ACD are largely unknown as there are only a few contradictory reports on this subject in the literature.

The reported sensitivity and specificity of MRA in diagnosing ACD in symptomatic patients with FAI varies significantly, ranging from 22% to 100% and 40% to 100%, respectively.^4,7,20,46 There is no consensus on the accuracy of MRA in detecting cartilage lesions in patients with FAI. Several studies have shown poor sensitivity and specificity for detecting cartilaginous lesions of the femoral head and acetabulum due to limited joint distensibility.

Konstantinidis et al²⁵ reported the lowest diagnostic value of MRA in detecting ACD in patients with FAI. They discovered that MRA sensitivity was 6%. These findings question the efficacy and diagnostic value of MRA for the preoperative detection of ACD in patients with FAI. This single-center retrospective review included consecutive patients who underwent surgery for symptomatic FAI. All patients underwent 1.5-T MRA preoperatively within 12 months. Two trained assessors compared the MRA reports with the surgical notes and videos of all the patients. The sensitivity, specificity, NPV, and PPV of MRA based on the assessor's reports were 6%, 98%, 27%, and 91%, respectively. ACD can be severely underdiagnosed by MRA in patients with FAI.

The diagnosis of cartilage delamination using MRA remains an arduous task. This may be due to hip joint distensibility being restricted. Some studies have suggested that plain MRI is more useful in detecting cartilage injuries in the hip than MRA.³¹ Rajeev et al³⁸ showed that the sensitivity for detecting cartilage delamination using MR arthrograms is very low (6%); however, the specificity is very high (97%), which is in agreement with other published studies.

Pfirrmann et al³⁷ specifically investigated this phenomenon and explained that the hip joint cartilage is quite thin, and there is difficulty identifying the delamination of the cartilage due to the narrow joint space. Moreover, the femoral head pushes the delaminated portion into the subchondral bone, obliterating the cleft, which is difficult to detect using MRA. Anderson et al⁴ reported that limited hip joint distensibility makes cartilage delamination difficult to identify. These findings may explain the poor sensitivity of MRA in detecting ACD.

However, some studies have reported contradictory results. According to Zaragoza et al,⁴⁶ MRA demonstrated high sensitivity (97%) and specificity (84%) for detecting ACD, and it is considered a valuable diagnostic tool in clinical practice. The PPV and NPV of MRA findings have been reported to be 90% and 94%, respectively. MRA was an effective diagnostic tool in this study. Several MRA findings that could indicate the presence of ACD have been described in the literature, and they are commonly used by radiologists and orthopaedic surgeons. They include the presence of fluid under the cartilage delamination (“inverted Oreo cookie” sign, a specific but rare finding),⁸ hypointense areas in the cartilage layer on intermediate-weighted fat-saturated or T1-weighted images,⁴⁸ a low signal intensity curvilinear flap >1 mm in thickness on T1-weighted images,⁴ and/or a hypointense line in the acetabular cartilage layer parallel to the subchondral plate.⁴⁸

The aforementioned findings suggest the need for better standard diagnostic criteria for cartilage delamination detection using MRA. Both orthopaedic surgeons and radiologists should be alert when examining an MR arthrogram to identify this pathology in symptomatic patients with FAI. New technologies may be helpful in accurately diagnosing this “hidden enemy”; nevertheless, more studies will be required in the future.

Treatment

ACD in the hip is one of the earliest precursors of osteoarthritis, and the intervention described ought to repair chondral damage before progression. Attempting repair of the delaminated cartilage is possible, as viable chondrocytes have been proven to survive within damaged cartilage.²¹

Microfracture or Debridement

Simple debridement of the damaged articular cartilage (chondroplasty) of the knee has been performed for several years.²² The rationale is to remove the degenerating and unstable chondral tissue and reduce the inflammatory matrix metalloproteinase load in the joint. A study by Hubbard²² showed improved outcomes up to 5 years after surgery. Microfracturing, drilling, and abrasion are variations of marrow stimulation techniques, in which the area of chondral damage is exposed to mesenchymal stem cells from the marrow cavity. Microfracture requires the removal of loose articular cartilage to expose the underlying subchondral bone. The lesion's edges must be stable and ideally create a sharp edge for containment of platelets and fibrin clots. In hip arthroscopy, this would necessitate excision of the delaminated cartilage flap from the underlying subchondral bone, thereby wasting potentially viable chondral tissue. However, progressive acetabular chondral damage may occur after the loss of compressive and shear force distribution in the area of defect, thereby resulting in increased loads on other acetabular regions. Flap refixation may mitigate this progression, but only if the flap remains viable and adequate osteochondral incorporation occurs through extracellular matrix production and osteochondral adherence.

Fibrin Adhesive

Fibrin adhesives have been used widely to enhance repair by acting as a scaffold for the ingrowth of native cells, as carriers for transplanted cells, and as vehicles for local drug delivery.^1,34 Bentley and Greer¹¹ have suggested the use of fibrin clot matrices containing transplanted cells, which becomes a scaffold to fill the cartilaginous defects. Fibrin adhesives cause accelerated sprouting of capillary vessels and ingrowth of mesenchymal stem cells, which promotes faster healing of defects.³ In vitro experiments have demonstrated that synthetic fibrin facilitates proliferation and differentiation of chondrocytes and the formation of a chondroid matrix.⁴²

As hyaline cartilage is enriched from the synovial fluid, microfractures may create keyholes to which fibrin glue can adhere, thereby stabilizing the flap and allowing healing of the underlying bone. Stafford et al⁴³ showed the midterm results of the novel use of fibrin glue in the treatment of ACD via hip arthroscopy. This technique uses microfracture and a fibrin adhesive to bond the delaminated articular cartilage to the underlying subchondral bone. They found that arthroscopic repair of the delaminated acetabular articular cartilage using a fibrin adhesive was useful for treating early cartilage damage. They reported the midterm results of 43 patients with FAI who underwent this technique for reattachment of delaminated chondral flaps. There was significant improvement in the modified Harris Hip Score for pain and function. However, further support from a multicenter, double-blinded, randomized controlled trial is needed.

Microfragmented Adipose Tissue Transplantation

Microfragmented adipose tissue transplantation (MATT) is an emerging option for the treatment of delamination, regardless of patient age. Mesenchymal stem cells are appropriate candidates for regenerating incurable defects in articular cartilage due to their inherent chondrogenic properties, easy availability, cell-homing potential, and immunomodulatory function.^5,18 Unlike bone marrow, adipose tissue–derived mesenchymal stem cells can be isolated in large quantities with minimal morbidity and discomfort.^2,17 MATT can be performed in patients with delamination or full-thickness symptomatic chondral defects. Autologous adipose tissue is harvested from the subcutaneous area of the lateral proximal thigh. The cellular component of the tissue is selected and isolated by simple washing using saline solution (Lipogems) and subsequently injected into the joint at the end of the arthroscopic procedure. The harvested adipose tissue is mechanically processed to produce microfragmented clusters rich in mesenchymal stem cells and perivascular cells during MATT. This process does not involve enzymatic digestion or cell culture and can be completed intraoperatively. The resulting product is injected arthroscopically into the joint, specifically targeting the chondral defect. This provides a biologically active matrix that serves as a cellular source and a scaffold, promoting cartilage repair through trophic and regenerative signaling. The acetabular chondral flap remains a potential chondrocyte source; however, these flaps may require biological augmentation to improve viability/proliferative capacity, extracellular matrix production, and incorporation. Future studies designed to specifically evaluate the basic scientific foundation of the proposed biological augmentations should include the effects of these augmentations on chondral viability, extracellular matrix production, hyaline preservation, and subchondral bone adherence (Figure 4).

Figure 4.

Intraoperative image of microfragmented adipose tissue transplantation. Lipogems injected directly into the delaminated area by a needle after water suction. (Adapted from Ivone et al.²³)

A recent study²³ compared the effectiveness of 2 different procedures (microfracture and MATT) for arthroscopic treatment of acetabular delamination. Microfracture involved creating multiple holes in the subchondral plate at the site of the chondral defect, allowing bone marrow–derived pluripotent cells to fill the damaged area. In contrast, in MATT, after subcutaneous adipose tissue is harvested, mesenchymal stem cells are incorporated into bioactive units that are injected into the joint to cover the chondral defect in a single arthroscopic surgical step. The mean modified Harris Hip Score of the MATT group increased from 53 ± 6 to 97.1 ± 3 after 2 years of follow-up, whereas that of the microfracture group increased from 50 ± 5 to 76 ± 12. This study's results show that MATT improves clinical outcomes. The MATT group showed durable improvement at the 2-year follow-up, with a significantly better score than the microfracture group, in which notable reduction in the clinical score was observed. However, further studies involving more patients with longer follow-up periods and other clinical and functional scores are necessary.

Chitosan-Based Scaffold (BST-CarGel)

Articular cartilage has poor intrinsic healing capacity; therefore, this technique has been developed to potentiate cartilage healing and reproduce new tissue with structural and biomechanical properties similar to those of normal cartilage. A recent study⁴⁴ showed the preliminary results of using BST-CarGel with microfracture for treating ACD associated with FAI. Preoperative evaluation was performed using various imaging methods and arthroscopic measurements. Thirteen patients who met the inclusion criteria were included in the study. Patients aged 18 to 50 years who underwent arthroscopic debridement and microfracture were selected for the study. Patients with defects >2 cm² were considered for the application of BST-CarGel and were included in the study. The Hip Outcome Score (HOS) was used pre- and postoperatively for the evaluation of functional outcome. To evaluate cartilage regeneration, delayed gadolinium-enhanced MRI of cartilage was used (Figure 5).

Figure 5.

(A) Arthroscopic image of a right hip joint showing acetabular chondral delamination before debridement. (B) Chondral defect after debridement and microfracture with bleeding from the penetration holes. (C) Application of BST-CarGel mixture by 18-gauge needle. (D) Covering of the whole defect with BST-CarGel mixture. (Adapted from Tahoun et al.⁴⁴)

The mean HOS for daily living activities improved from 64.4 to 87.4, and for the Sports Subscale, it improved from 35.2 to 75.2, which was highly significant. All patients had >90% filling of the chondral defect. As described above, the use of BST-CarGel as a scaffold material after microfracture can maintain good functional outcomes in patients with FAI associated with ACD. In addition, a comparative cohort study demonstrated that BST-CarGel combined with microfracture yielded significantly better clinicoradiological outcomes at a 2-year follow-up than microfracture alone, including lower joint space narrowing and reduced conversion rates to total hip arthroplasty.²⁴ A longer follow-up period and analysis of the repaired cartilage tissue using quantitative and qualitative radiological investigations are required to reach a final conclusion.

Chondral Nail Fixation

Chondral nail fixation is a recently introduced arthroscopic technique designed to stabilize ACD in patients with FAI. This method involves physically reattaching the unstable chondral flap to the subchondral bone using bioabsorbable nails, thereby preserving viable cartilage and promoting biological repair. A recent propensity-matched study⁴⁷ demonstrated that patients undergoing chondral nail fixation showed significantly greater pain relief, higher achievement of patient acceptable symptom state, and superior healing of ACD on postoperative MRI compared with those who underwent simple debridement.

The technique may also benefit from the combined effect of mechanical stabilization and marrow stimulation via microfracture. While promising, further long-term and multicenter studies are needed to confirm its clinical superiority and durability.

Discussion

Abnormal contact between the femoral head and acetabulum in patients with FAI results in damage to the cartilage and labrum in the hip joint. ACD is a common finding in patients with FAI, causing hip pain, instability, and reduced joint function. Therefore, it is important to accurately diagnose ACD through imaging assessment in patients with FAI for surgeons to anticipate their findings involving the labrum, articular cartilage, and osseous pathology, and to discuss specific surgical treatment options with patients before surgery.

Diagnosing ACD can be difficult as it is invisible on standard imaging studies such as radiographic imaging. However, specialized imaging techniques, including MRI and MRA, may detect this condition. MRI can provide detailed images of the hip joint, including the articular cartilage, labrum, and surrounding soft tissues, which can help identify and characterize delamination. Several studies in this systematic review^29,35,41 have shown that MRI is a valuable tool for diagnosing ACD in patients with FAI.

Furthermore, femoral osteoplasty is crucial in the surgical treatment of FAI. The technical variability of femoral osteoplasty is challenging even for experienced surgeons, and its effect on clinical outcomes can be substantial. An anatomic femoral osteoplasty without cartilage repair may yield superior outcomes in some cases compared with a technically inadequate osteoplasty combined with cartilage repair. However, evaluating an osteoplasty's quality remains difficult, despite 3-dimensional imaging, as commonly used metrics like the alpha angle and femoral head-neck offset may not fully capture instances of over- or underresection. Consequently, future research should aim to standardize the femoral osteoplasty's assessment to improve the reliability of clinical outcomes. In addition, capsular management is an important factor in FAI surgery, and it is relatively easier to standardize compared with femoral osteoplasty.

We concluded that MRI is a valuable tool for diagnosing ACD in patients with FAI and can help guide treatment decisions. In addition, MRI is a reliable noninvasive tool for identifying delamination in this population. Notably, MRI may not always detect small or superficial delamination. Therefore, in cases in which standard MRI scans are inconclusive, specialized imaging techniques such as MRA may aid in making accurate diagnosis. MRA can provide a more distinct view of the boundaries of intra-articular structures by injecting a small amount of fluid into the joint, thereby enabling a more precise diagnosis of articular cartilage damage compared with MRI. The diagnostic accuracy of MRA is high. However, MRA is more expensive than MRI, and some patients may refuse the procedure as it requires fluid injection into the joints. Furthermore, MRA is more extensive, requires more experienced physicians than MRI, and, as noted in our results, may yield inconsistent findings.

Previous studies have suggested that anatomic features of the hip joint, including cartilage thinness and limited joint distension, make detecting delamination difficult, despite advanced imaging modalities such as MRA.^4,37 Therefore, considering that imaging findings are not ideal for the diagnosis of ACD in patients with FAI is important. Clinical correlation and physical examination findings should always be considered along with imaging findings to improve diagnostic accuracy and plan appropriate treatment.

Debridement and microfracture, which are easily performed and cost-effective, are considered the standard methods for treating cartilage defects. However, articular cartilage has poor intrinsic healing capacity. Therefore, several techniques have been developed to potentiate cartilage healing and produce new tissues with structural and biomechanical properties similar to those of normal cartilage.

Fibrin adhesive is made using fibrinogen, which is a blood-clotting protein. The adhesive has been used to treat ACD in patients with FAI. The fibrin adhesive stabilizes the transplanted tissue in the damaged cartilage area and allows the regenerated cartilage tissue to grow stably in the transplanted area. Furthermore, it reduces postoperative bleeding and pain. Studies have shown that treatment using fibrin adhesive yielded good results for ACD in patients with FAI. In a study by Stafford et al,⁴³ patients who underwent surgery using fibrin adhesive showed symptom improvement after surgery. Moreover, the quality of the regenerated cartilage tissue improved in these patients.

MATT combines microfracture and cartilage transfer. It facilitates the formation of new cartilage cells through microfractures; thereafter, cartilage transfer is used to transplant healthy cartilage tissue into the damaged area to treat the damaged cartilage. In the study by Ivone et al,²³ the chondral flap was preserved in situ and biologically augmented using microfragmented adipose tissue, which enhanced chondrocyte viability and promoted integration. Ivone et al²³ showed that MATT can effectively treat ACD. However, MATT requires a longer rehabilitation period after surgery due to the time required for new cartilage cell formation. Furthermore, consistent follow-up testing is necessary after treatment.

Chitosan-based scaffolds are newly developed materials in cartilage tissue engineering. Chitosan is a polysaccharide extracted from shells, with high biocompatibility and properties that induce cell proliferation and differentiation. Based on these characteristics, chitosan-based scaffolds can be transplanted into damaged cartilage areas to induce cartilage formation and promote regeneration. Tahoun et al⁴⁴ demonstrated that treatment with chitosan-based scaffolds yielded effective results in patients with FAI and mild ACD. However, further research and long-term studies on the aforementioned treatment methods are needed, and long-term observation of the durability of regenerated cartilage tissue is necessary. Furthermore, consistent postoperative follow-up testing is necessary.

This study is an important addition to the hip cartilage literature in that it carefully evaluated the biological support, or lack thereof, behind the currently utilized clinical treatments, thereby creating opportunities for further similar evaluations of other techniques.

Conclusion

Advanced research and understanding of ACD in patients with FAI may be crucial in the development of accurate preoperatively targeted treatments and preventive strategies.

Footnotes

Final revision submitted July 30, 2025; accepted September 1, 2025.

The authors declared that they have 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 was not sought for the present study.

ORCID iDs

Suk-Kyoon Song

Soshi Uchida

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An Updated Review on the Diagnosis and Treatment of Acetabular Cartilage Delamination in Patients With Femoroacetabular Impingement

Abstract

Background:

Purpose:

Study Design:

Methods:

Results:

Conclusion:

Keywords

Methods

Results

Diagnosis

Magnetic Resonance Imaging

Magnetic Resonance Arthrography

Treatment

Microfracture or Debridement

Fibrin Adhesive

Microfragmented Adipose Tissue Transplantation

Chitosan-Based Scaffold (BST-CarGel)

Chondral Nail Fixation

Discussion

Conclusion

Footnotes

ORCID iDs

References