The biology and clinical evidence of microfracture in hip preservation surgery

Save the subchondral bone plate: Debridement versus bone marrow stimulation in acetabular cartilage defects over 60 months of follow-up

PURPOSE

Bone marrow stimulation is a common treatment for full-thickness cartilage defects in the hip joint. However, common procedures may result in poor fibrous repair tissue and changes to the subchondral anatomy. This study investigated the clinical outcome of a cohort of International Cartilage Repair Society (ICRS) grades 3 and 4 cartilage defects treated with bone marrow stimulation compared to those who received simple debridement/chondroplasty.

METHODS

In this retrospective registry study, 236 patients with uni-focal acetabular chondral lesions of the hip up to 400 mm² (mean 177.4 ± 113.4 mm²) and of ICRS grade ≥3 with follow-up of at least 12 months (mean 33.2 ± 15.3 months) were included. Eighty-one patients underwent bone marrow stimulation (microfracture: n = 44, abrasion: n = 37) besides treatment of the underlying pathology, 155 patients underwent defect debridement/chondroplasty. The patient-reported outcome was measured using the International Hip Outcome Tool 33 (iHOT33) score and the Visual Analogue Scale (VAS) for pain.

RESULTS

iHOT33 and VAS both improved highly statistically significantly (p < 0.001) in the debridement group after 6, 12, 24, 36 and 60 months compared to the preoperative scores, whereas iHOT33 and VAS after microfracture or abrasion did not show statistically significant changes over time. Twenty-four and sixty months postsurgery the debridement group revealed significant higher scores in the iHOT33 compared to the bone marrow stimulation groups.

CONCLUSION

Patients with chondral lesions of the hip ≤400 mm2 sustainably benefit from arthroscopic debridement under preservation of the subchondral bone plate in terms of functional outcome and pain in contrast to patients treated with bone marrow stimulation. These findings discourage the currently recommended use of microfracture in the hip joint.

LEVEL OF EVIDENCE

Level III.

Autologous Matrix-Induced Chondrogenesis for the Treatment of Hip Acetabular Chondral Lesions Demonstrates Improved Outcomes: A Systematic Review

PURPOSE

To systematically investigate the outcomes of patients who underwent autologous matrix-induced chondrogenesis (AMIC) during hip arthroscopy for the treatment of acetabular chondral lesions due to femoroacetabular impingement syndrome.

METHODS

PubMed and Cochrane were queried in June 2022 to conduct this systematic review using the following keywords: "femoroacetabular impingement," "arthroscopy," "microfracture," and "autologous matrix-induced chondrogenesis." Articles were included if they reported on patient-reported outcomes of AMIC during hip arthroscopy to treat chondral lesions of the hip. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Each study was queried for demographics, lesion classification, surgical treatment, patient-reported outcome scores, revision arthroscopy, and conversion to total hip arthroplasty (THA). A qualitative subanalysis was performed to compare patients undergoing AMIC to patients undergoing microfracture alone if included studies also assessed results of microfracture alone.

RESULTS

Four studies met inclusion criteria and assessed 209 hips undergoing AMIC. The included studies consisted of 99 male and 110 female patients. Mean postoperative follow-up ranged from 1 to 8 years, and mean patient age ranged from 34.3 to 45 years. Three of the 4 included studies reported the modified Harris Hip Score, and all 3 of these studies reported statistically significant improvement in the modified Harris Hip Score at final follow-up (P < .001) with mean preoperative values ranging from 44.5 to 62.8 and mean postoperative values ranging from 78.8 to 95.8. Two of the 4 studies compared patients treated with AMIC to microfracture alone. In these 2 studies, the AMIC groups reported 0 patients converting to THA while the microfracture-alone groups reported a highly variable rate of conversion to THA (2%-32.6%).

CONCLUSIONS

Patients who underwent hip arthroscopy and AMIC for the treatment of femoroacetabular impingement syndrome and acetabular chondral lesions demonstrated improved patient-reported outcomes and low rates of secondary surgeries at short-term follow-up. STUDY DESIGN: Level IV, systematic review of Level III and IV studies.

Minced Cartilage Implantation in Acetabular Cartilage Defects: Case Series with 2-Year Results

OBJECTIVE

The objective was to evaluate clinical outcome and safety of arthroscopic, autologous minced cartilage implantation for acetabular cartilage lesions observed during hip arthroscopy to treat femoroacetabular impingement syndrome (FAIS).

DESIGN

Eleven male patients, average age: 29.4 ± 5.4 years, average body mass index (BMI): 24.2 ± 2.2 kg/m2, scheduled for hip arthroscopy due to FAIS accompanied by an acetabular cartilage lesion were included in the case series. Cartilage tissue was harvested and minced from the loose cartilage flap at the chondrolabral lesion by arthroscopic shaver, augmented with autologous conditioned plasma, implanted into the defect, and fixated by autologous thrombin. Concomitant interventions were performed as indicated. The patients were evaluated preoperatively and at 24-month follow-up, using the International Hip Outcome Tool-12 (iHOT-12) and Visual Analog Scale (VAS) pain score and by magnetic resonance imaging (MRI) using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) grading scale at the 2-year follow-up.

RESULTS

The defect size was on average 3.5 cm2 (1.5-4.5 cm2). From preoperatively to 2 years postoperatively, the iHOT-12 significantly improved from 50.2 ± 18 to 86.5 ± 19 (P < 0.0001), and pain score decreased from 5.6 ± 1.8 to 1.0 ± 1.5 (P < 0.0001) on the Visual Analog Scale pain score. Regarding functional outcome and pain, 10 of the 11 patients and all patients reached the minimal clinically important difference (MCID), respectively. The postoperative average MOCART score was 87.2 (± 9.2). No adverse events or reoperations were observed.

CONCLUSIONS

Arthroscopic, autologous minced cartilage implantation for treating full-thickness acetabular cartilage lesions in FAIS shows statistically and clinically significant improvement at short-term follow-up.

Outcomes of arthroscopy of the hip for femoroacetabular impingement based on intraoperative assessment using the Outerbridge classification

Aims

Hip arthroscopy (HA) has become the treatment of choice for femoroacetabular impingement (FAI). However, less favourable outcomes following arthroscopic surgery are expected in patients with severe chondral lesions. The aim of this study was to assess the outcomes of HA in patients with FAI and associated chondral lesions, classified according to the Outerbridge system.

Methods

A systematic search was performed on four databases. Studies which involved HA as the primary management of FAI and reported on chondral lesions as classified according to the Outerbridge classification were included. The study was registered on PROSPERO. Demographic data, patient-reported outcome measures (PROMs), complications, and rates of conversion to total hip arthroplasty (THA) were collected.

Results

A total of 24 studies were included with a total of 3,198 patients (3,233 hips). Patients had significantly less improvement in PROMs if they had Outerbridge grade III and IV lesions (p = 0.012). Compared with microfracture, autologous matrix-induced chondrogenesis (AMIC) resulted in significantly reduced rates of conversion to THA (p = 0.042) and of revision arthroscopy (p = 0.038). Chondral repair procedures in these patients also did not significantly reduce the rates of conversion to THA (p = 0.931), or of revision arthroscopy (p = 0.218). However, compared with microfracture, AMIC significantly reduced the rates of conversion to THA (p = 0.001) and of revision arthroscopy (p = 0.011) in these patients. Those with Outerbridge grade III and IV lesions also had significantly increased rates of conversion to THA (p = 0.029) and of revision arthroscopy (p = 0.023) if they had associated lesions of the acetabulum and femoral head. Those who underwent labral debridement had a significantly increased rate of conversion to THA compared with those who underwent labral repair (p = 0.015).

Conclusion

There is universal improvement in PROMs following HA in patients with FAI and associated chondral lesions. However, those with Outerbridge grade III and IV lesions had significantly less improvement in PROMs and a significantly increased rate of conversion to THA than those with Outerbridge grade I and II. This suggests that the outcome of HA in patients with FAI and severe articular cartilage damage may not be favourable.

[Minced cartilage procedure for the treatment of acetabular cartilage lesions of the hip joint]

OBJECTIVE

Treatment of acetabular cartilage defects using autologous cartilage fragments.

INDICATIONS

Acetabular cartilage damage (1-6 cm2) associated with femoroacetabular impingement syndrome (FAIS).

CONTRAINDICATIONS

Advanced osteoarthritis (≥ 2 according to Tönnis) and extensive acetabular cartilage damage > 6 cm2. Lack of labral containment due to irreparable labral damage.

SURGICAL TECHNIQUE

Arthroscopic preparation of the acetabular cartilage damage and removal of unstable cartilage fragments using a 4.0 mm shaver, which minces the cartilage fragments. If necessary, additional cartilage harvesting over the CAM morphology requiring resection. Collection of the cartilage fragments using GraftnetTM and augmentation with autologous conditioned plasma (ACP). Treatment of associated pathologies such as CAM morphology, pincer morphology, and labral refixation or reconstruction. Implantation of cartilage mass and remodeling into the defect zone. Final sealing with autologous fibrin.

POSTOPERATIVE MANAGEMENT

Postoperatively, weight bearing is restricted to 20 kg and range of motion to 90° of flexion for 6 weeks. This is supplemented by passive movement using a continuous passive motion (CPM) device.

RESULTS

Since 2021, 13 patients treated with the described method were followed up for at least 6 months. A significant increase in the International Hip Outcome Tool (iHot)-12 and a significant reduction of pain were observed. No severe complications occurred.

Patients with Small Acetabular Cartilage Defects Caused by Femoroacetabular Impingement Do Not Benefit from Microfracture

OBJECTIVE

According to current recommendations, large cartilage defects of the hip over 2 cm2 are suggested to undergo autologous chondrocyte transplantation (ACT), while small defects should be treated with microfracture. We investigated if patients with small chondral defects of the hip joint (≤100 mm2) actually benefit from microfracture.

DESIGN

In this retrospective multicenter cohort study 40 patients with focal acetabular cartilage defects smaller than 100 mm2 and of ICRS grade ≥2 caused by femoroacetabular impingement were included. Twenty-six unrandomized patients underwent microfracture besides treatment of the underlying pathology; in 14 patients cartilage lesions were left untreated during arthroscopy. Over a mean follow-up of 28.8 months patient-reported outcome was determined using the iHOT33 (international hip outcome tool) and the VAS (visual analog scale) for pain.

RESULTS

The untreated group showed a statistically significant improvement of the iHOT33 after 12 (p = 0.005), 24 (p = 0.019), and 36 months (p = 0.002) compared to the preoperative score, whereas iHOT33 in the microfracture group did not reveal statistically significant changes over time. There was no significant difference between both groups on any time point. Regarding pain both groups did not show a significant improvement over time in the VAS.

CONCLUSION

The subjective outcome of patients with small cartilage defects of the hip (≤100 mm2) improves 12 months after arthroscopic FAIS surgery without any cartilage treatment. However, no improvement could be seen after microfracture. Therefore, a reserved surgical treatment for small cartilage defects of the hip under preservation of the subchondral bone is recommended especially if a simultaneous impingement correction is performed.

Sport Activity and Clinical Outcomes after Hip Arthroscopy with Acetabular Microfractures at a Minimum 2-Year Follow-Up: A Matched-Pair Controlled Study

Background: Acetabular microfractures for cartilage lesions have been shown to be a safe procedure able to improve patient reported outcomes (PROs). Nevertheless, the return to sport activity rate represents a crucial outcome to be investigated in these young athletic patients. Methods: Patients undergoing acetabular microfracture for full chondral acetabular lesions were compared to a 1:1 matched-pair by age and gender control group undergoing hip arthroscopy without microfractures. Clinical assessment was performed with PROs and participation in sports in terms of type and level of activities was evaluated preoperatively and at 2-years follow-up. Results: A total of 62 patients with an average age of 35.1 ± 8.1 (microfracture group) and 36.4 ± 6.3 (control group) were included. In both groups, the average values of PROs significantly increased from preoperatively to the last follow-up. There was no significant difference between the two groups in the number of patients playing at the amateur and elite level preoperatively and at the last follow-up. Conclusions: Microfractures for the management of full-thickness acetabular chondral defect provides good clinical results at a minimum follow-up of two years, which are not inferior to a matched-pair control group. Patients undergoing this procedure are likely able to return at the same level of sport before surgery.

Lower Center Edge Angle and Bioipolar Cartilage Lesions Are Associated With Conversion to Hip Arthroplasty Within 2 Years Following Hip Arthroscopy: A Matched Cohort Analysis

PURPOSE

The purpose of this study was to determine whether radiographic parameters, intraoperative findings, patient-reported outcome measures, or intraoperative interventions that were performed differentiate those patients with >2 mm of joint space who convert under two years to total hip arthroplasty (THA) after undergoing hip arthroscopy for femoroacetabular impingement (FAI) when compared to those converting after 2 years.

METHODS

Included in this study were patients who underwent conversion to THA within 2 years of primary hip arthroscopy from a prospectively collected patient registry from 2007 to 2017. Patients who underwent early conversions to arthroplasty were matched 1:1 with patients who converted after 2 years, based upon age and gender. Preoperative outcome scores were collected, including Short Form-12, modified Harris Hip Score, and Hip Outcome Score. Additionally, variables from the preoperative radiographic evaluation, surgical findings, and procedures performed were also compared.

RESULTS

Forty-nine patients were included in the early conversion group and were matched with 49 patients in the later conversion group. Patients with lateral center edge angles of less than 25° were more likely to be in the early failure group [OR: 3.9; 95% CI: 1.01 to 15]. Patients with unipolar chondral defects on either the femoral (P = .128) or acetabular side (P = .656) were not at increased odds for early conversion compared to later conversion; however, those with bipolar chondral lesions at the time of surgery had increased odds of early conversions [OR: 3.3; 95% CI: 1.4 to 8] (P = .01). Neither surgical treatment nor preoperative patient-reported outcome measures were associated with early conversion.

CONCLUSIONS

In patient with >2 mm of joint space, lateral center edge angles of less than 25° and those with bipolar articular cartilage lesions seen at the time of hip arthroscopy are at increased risk for conversion to total hip arthroplasty within two years.

LEVEL OF EVIDENCE

Level III, retrospective comparison study.

Comparison of the Effect of MFAT and MFAT + PRP on Treatment of Hip Osteoarthritis: An Observational, Intention-to-Treat Study at One Year

Hip osteoarthritis (OA) is a major contributor to reduced quality of life and concomitant disability associated with lost working life months. Intra-articular injection of various biological materials has shown promise in alleviating symptoms and potentially slowing down the degenerative process. Here, we compared the effects of treatment of a cohort of 147 patients suffering from grade 1–4 hip OA; with either micro-fragmented adipose tissue (MFAT), or a combination of MFAT with platelet-rich plasma (PRP). We found significant improvements in both the visual analogue score for pain (VAS) and Oxford hip score (OHS) that were similar for both treatments with over 60% having an improvement in the VAS score of 20 points or more. These results suggest a positive role for intra-articular injection of MFAT + PRP as a treatment for hip osteoarthritis which may be important particularly in low body mass index (BMI) patients where the difficulty in obtaining sufficient MFAT for treatment could be offset by using this combination of biologicals.

Treatment of Full-Thickness Acetabular Chondral Flaps During Hip Arthroscopy: Bone Marrow Aspirate Concentrate Versus Microfracture

Background:

The optimal treatment strategy for patients with full-thickness chondral flaps undergoing hip arthroscopy is controversial.

Purpose:

To compare functional outcomes of patients who underwent bone marrow aspirate concentrate (BMAC) application with those of patients who underwent microfracture.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This was a retrospective case series of prospectively collected data on patients who underwent arthroscopic acetabular labral repair by 1 surgeon between June 2014 and April 2020. The inclusion criteria for this study were age ≥18 years, preoperative radiographs of the pelvis, arthroscopic acetabular labral repair, exposed subchondral bone with overlying chondral flap seen at the time of hip arthroscopy, microfracture or BMAC to address this lesion, and completed patient-reported outcome measures (PROMs) (International Hip Outcome Tool–33 [iHOT-33], Hip Outcome Score–Activities of Daily Living [HOS-ADL], Hip Outcome Score–Sports Subscale [HOS-Sport], modified Harris Hip Score [mHHS], and visual analog scale [VAS] for pain) at enrollment and 12-month follow-up. Clinical outcomes were assessed using PROM scores.

Results:

A total of 81 hips with full-thickness chondral flaps were included in this study: 50 treated with BMAC and 31 treated with microfracture. There were no significant differences between groups in age, sex, body mass index, tear size, radiographic osteoarthritis, or radiographic femoroacetabular impingement. In the BMAC cohort, all PROM scores improved significantly from preoperatively to follow-up: 41.7 to 75.6 for iHOT-33, 67.6 to 91.0 for HOS-ADL, 41.5 to 72.3 for HOS-Sport, 59.4 to 87.2 for mHHS, and 6.2 to 2.2 for VAS pain (P < .001 for all). In the microfracture cohort, the score improvements were 48.0 to 65.1 for iHOT-33 (P = .001), 80.5 to 83.3 for HOS-ADL (P = .275), 59.2 to 62.4 for HOS-Sport (P = .568), 70.4 to 78.3 for mHHS (P = .028), and 4.9 to 3.6 for VAS pain (P = .036). Regarding clinically meaningful outcomes, 77.6% of the BMAC group and 50.0% of the microfracture group met the minimal clinically important difference for iHOT-33 at the 12-month follow-up (P = .013).

Conclusion:

Patients with full-thickness chondral flaps at the time of hip arthroscopy experienced greater improvements in functional outcome scores at the 12-month follow-up when treated with BMAC as opposed to microfracture.

[Update on the Operative Treatment of Cartilage Defects]

Focal cartilage defects lead to swelling, significant pain and loss of function of the affected joint. Additionally, they are linked to early onset of osteoarthritis. Often young and active patients are especially susceptible due to the high stress placed on their joints. A vast amount of treatment options is available to orthopaedic surgeons to cure cartilage defects of the knee, hip, shoulder, elbow and ankle joints. This article serves to give an overview of these available treatment options and to explain the expected outcomes.

Microfracture in Hip Arthroscopy. Keep It Simple!

Despite all the advances in hip arthroscopy, microfracture is still the workhorse for treating focal and full-thickness cartilage lesions. The success of this treatment is owed to its reliability and simplicity. Given the structure of the hip joint, however, there are challenges to this procedure using a conventional microfracture pick. This note presents our current and preferred microfracture technique using a curve drill guide and flexible drill. This method offers greater range of access to different regions of the joint with ease, thus ensuring a reproducible and quicker procedure with less risk.

Primary labral reconstruction in patients with femoroacetabular impingement, irreparable labral tears and severe acetabular chondral defects decreases the risk of conversion to total hip arthroplasty: a pair-matched study

In the presence of severe acetabular cartilage defects, the benefits of labral reconstruction (RECON) versus labral resection (RESEC) have not been determined. Prospectively collected data between October 2008 and December 2016 were retrospectively reviewed. Inclusion criteria were hip arthroscopy, acetabular Outerbridge grade III/IV, irreparable labral tears that underwent RECON or RESEC, and minimum 2-year postoperative measures for the modified Harris Hip Score, Non-Arthritic Hip Score, Hip Outcome Score-Sports Specific Subscale, International Hip Outcome Tool, Patient Satisfaction and Visual Analogue Scale for pain. Exclusion criteria included Tönnis grade >1, previous hip conditions or previous ipsilateral hip surgeries. A 1:1 matched-pair analysis was performed based on age ±5 years, sex, body mass index ±5 kg/m², Tönnis grade, acetabular microfracture, femoral Outerbridge grade (0 or I compared with II, III or IV). Relative risk (RR) and conversion rate to total hip arthroplasty (THA) were calculated. A total of 38 RECON hips were successfully matched. Both groups demonstrated significant improvements in patient-reported outcomes (PROs). THA conversion was 5.3% and 21.1% for the RECON and RESEC groups, respectively (P = 0.04). RECON was four times less likely to require THA conversion than the RESEC group (RR=4.0; 95% CI 0.91-17.63). In the setting of primary arthroscopic management of femoroacetabular impingement, irreparable labral tears and acetabular chondral lesions of Outerbridge III/IV, patients that underwent RECON and RESEC experienced significant improvement in PROs at minimum 2-year follow-up, and these functional scores were comparable when groups were matched. However, RR and rate to THA conversion were significantly higher in the RESEC group.

Predictors of Outcomes After Hip Arthroscopic Surgery for Femoroacetabular Impingement: A Systematic Review

Background

The benefits of hip arthroscopic surgery in the setting of femoroacetabular impingement (FAI) have been well established; however, some patients may experience a greater degree of improvement than others. Identifying positive and negative predictors of outcomes would assist the orthopaedic surgeon's management algorithm for patients with FAI.

Purpose/Hypothesis

The objective of this systematic review was to identify demographic, radiographic, and other operative predictors of positive and negative outcomes after hip arthroscopic surgery for patients with FAI. It was hypothesized that factors including FAI morphology, age, body mass index (BMI), sex, dysplasia, articular cartilage damage, radiographic joint space, and labral treatment would predict outcomes after hip arthroscopic surgery.

Study Design

Systematic review; Level of evidence, 4.

Methods

This systematic review was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Three databases (Embase, PubMed, and Ovid [MEDLINE]) were searched on May 19, 2018, using terms including "hip," "arthroscopy," and "FAI." Studies were screened and data extracted in duplicate.

Results

A total of 39 studies were included in this systematic review, comprising 9272 hips with a mean age of 36.5 years (47.2% female). Younger age, male sex, lower BMI (<24.5 kg/m²), Tönnis grade 0, and preoperative pain relief from diagnostic intra-articular hip injections predicted positive outcomes. Female sex, older age (>45 years), longer duration of preoperative symptoms (>8 months), elevated BMI, increased Tönnis grade (≥1), chondral defects, decreased joint space (≤2 mm), increased Kellgren-Lawrence grade (>3), increased lateral center-edge angle (LCEA), and undergoing labral debridement alone were predictors of negative outcomes.

Conclusion

In patients with FAI, younger age, male sex, lower BMI (<24.5 kg/m²), Tönnis grade 0, and pain relief from preoperative intra-articular hip injections are significantly more likely to achieve positive outcomes after hip arthroscopic surgery. On the other hand, older age (>45 years), female sex, elevated BMI, osteoarthritic changes, decreased joint space (≤2 mm), chondral defects, increased LCEA, and undergoing labral debridement compared with labral repair are associated with negative outcomes.

Is Microfracture Necessary? Acetabular Chondrolabral Debridement/Abrasion Demonstrates Similar Outcomes and Survival to Microfracture in Hip Arthroscopy: A Multicenter Analysis

BACKGROUND

Hip arthroscopy is becoming more advanced and commonly performed. However, significant controversy exists regarding whether high-grade acetabular cartilage lesions should be treated with debridement/abrasion or microfracture. In addition, patients treated with microfracture are subject to extended protected weightbearing rehabilitation to mitigate risk of subchondral plate fracture and to protect fibrocartilage tissue formation.

PURPOSE

To determine the midterm patient-reported outcomes and failure rate of patients with grade 3 and 4 acetabular labrum articular disruption (ALAD) lesions managed with debridement/abrasion or microfracture.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Primary arthroscopic labral repair cases at 2 centers from November 2008 to April 2016 were reviewed for patients aged <55 years with unipolar ALAD grade 3 and 4 chondrolabral acetabular delamination. Patients undergoing microfracture and debridement/abrasion were compared using the visual analog pain scale (VAS), modified Harris Hip Score (mHHS), and Hip Outcome Score-Sports-Specific Subscale (HOS-SSS) to determine predictors of outcomes and failure.

RESULTS

A total of 113 hips in 110 patients (66 males, 44 females; mean age, 34.5 ± 1.1 years) undergoing debridement/abrasion (n = 82) or microfracture (n = 31) were followed for a mean of 4.9 years (range, 2.0-8.5 years). Lesion size was not statistically different between the debridement/abrasion (1.3 ± 1.0 cm²) and microfracture cohorts (1.4 ± 1.0 cm²) ( P = .47). Patients undergoing debridement/abrasion achieved 3.6-point mean improvements in VAS ( P < .01), 21.2-point improvements in mHHS ( P < .01), and 25.4-point improvements in HOS-SSS ( P < .01), which were not significantly different from those observed in microfracture patients ( P≥ .20). The 5-year rate of survival free of revision surgery was 84.0% in the debridement/abrasion group and 85.6% in the microfracture group ( P = .78). The cartilage treatment technique was found not to be predictive of revision risk during both univariate (hazard ratio [HR], 1.01; P = .98) and multivariate (HR, 0.93; P = .90) analysis accounting for patient age, lesion grade, and acetabular coverage.

CONCLUSION

Patients undergoing debridement/abrasion of high-grade unipolar acetabular cartilage lesions demonstrate similar outcome scores and revision rates compared with those of patients undergoing microfracture. These outcomes support the consideration of preferential debridement/abrasion at the discretion of the treating surgeon to optimize recovery while maintaining established positive outcomes after hip arthroscopy.

Mesenchymal stem cells for cartilage regeneration in dogs

Articular cartilage damage and osteoarthritis (OA) are common orthopedic diseases in both humans and dogs. Once damaged, the articular cartilage seldom undergoes spontaneous repair because of its avascular, aneural, and alymphatic state, and the damage progresses to a chronic and painful situation. Dogs have distinctive characteristics compared to other laboratory animal species in that they share an OA pathology with humans. Dogs can also require treatment for naturally developed OA; therefore, effective treatment methods for OA are desired in veterinary medicine as well as in human medicine. Recently, interest has grown in regenerative medicine that includes the use of mesenchymal stem cells (MSCs). In cartilage repair, MSCs are a promising therapeutic tool due to their self-renewal capacity, ability to differentiate into cartilage, potential for trophic factor production, and capacity for immunomodulation. The MSCs from dogs (canine MSCs; cMSCs) share various characteristics with MSCs from other animal species, but they show some deviations, particularly in their differentiation ability and surface epitope expression. In vivo studies of cMSCs have demonstrated that intraarticular cMSC injection into cartilage lesions results in excellent hyaline cartilage regeneration. In clinical situations, cMSCs have shown great therapeutic effects, including amelioration of pain and lameness in dogs suffering from OA. However, some issues remain, such as a lack of regulations or guidelines and a need for unified methods for the use of cMSCs. This review summarizes what is known about cMSCs, including their in vitro characteristics, their therapeutic effects in cartilage lesion treatment in preclinical in vivo studies, their clinical efficacy for treatment of naturally developed OA in dogs, and the current limitations of cMSC studies.

Acetabular microfracture in hip arthroscopy: clinical outcomes with minimum 5-year follow-up

INTRODUCTION

There is a paucity in the literature regarding mid-term results of microfracture in hip arthroscopy. We aim to assess 5-year outcomes of patients who underwent acetabular microfracture for full-thickness chondral lesions as a part of hip arthroscopy.

METHODS

Between August 2008 and September 2011, data were prospectively gathered for patients undergoing acetabular microfracture during hip arthroscopy with minimum 5-year follow-up. All patients were assessed pre- and postoperatively, with modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), Hip Outcome Score - Sports Specific Subscale (HOS-SSS), and visual analog scale (VAS). International Hip Outcome Tool (iHOT-12) and satisfaction were collected postoperatively. Exclusion criteria included previous hip conditions, or preoperative Tönnis grade ≥2.

RESULTS

Fifty three hips were eligible for this study. Of these, 43 (81.1%) hips in 42 patients had follow-up. The study group had a male majority (65.1%) and an average age of 44.4 ± 9.5 years. There was statistically significant improvement in all patient-reported outcomes (PROs) and VAS at follow-up. Patient satisfaction was 7.6 ± 2.6. A comparison of 2-year to minimum 5-year follow-up results identified no statistically significant deterioration in PROs, VAS, and patient satisfaction. Survivorship was 72.1% with 12 patients converted to total hip arthroplasty (THA). 4 patients (10.8%) underwent secondary arthroscopy.

CONCLUSIONS

In the mid-term, microfracture as a part of hip arthroscopy demonstrated favourable outcomes and 72% survivorship. Careful patient selection is warranted to limit the risk of conversion to THA.

[Cartilage regeneration surgery on the hip : What is feasible?]

Localized cartilage defects at the hip are mainly caused by pre-arthritic deformities, particularly by cam-type femoroacetabular impingement (FAI). Timely elimination of symptomatic deformities can prevent further progression such as cartilage defects. As the defects mostly occur in the anterolateral part of the acetabulum, they can be easily treated either by open surgery or by arthroscopy. To date the most effective methods of treatment are bone marrow stimulation, with or without a covering of biomaterials, and autologous chondrocyte transplantation. In selected cases, readaptation of the damaged cartilage can be attempted by biological procedures. In the present article, the findings reported in current studies on these procedures are summarized and discussed in detail. An outlook is given regarding possible future treatment concepts.

Use of Bone Marrow Aspirate Concentrate with Acetabular Labral Repair for the Management of Chondrolabral Junction Breakdown

Despite advances in techniques for acetabular labral repair, strategies for mitigating or reversing damage to the chondrolabral junction do not yet exist. Cartilage repair techniques such as autologous chondrocyte implantation, matrix-induced autologous chondrocyte implantation, osteochondral autograft transfer, microfracture, and bone marrow aspirate concentrate (BMAC) have all been suggested to restore joint congruity and minimize further chondral deterioration. However, chondrocyte implantation techniques and osteochondral grafts are technically challenging in the hip because of its constrained nature, and many cell-based therapies have shown suboptimal results near the chondrolabral junction because of the increased shear forces at the peripheral acetabulum and increased stress at the weight-bearing region of the joint. By using BMAC to augment labral repairs and coat chondrolabral junction breakdown, we are able to introduce mesenchymal stem cells to peripheral acetabular tissue with little to no drawbacks, while avoiding donor-site morbidity, open procedures, and multiple surgeries. The purpose of this Technical Note is to describe a reproducible method for harvesting, processing, and applying BMAC to the chondrolabral surface of the hip during hip arthroscopy without the need for donor-site morbidity or increased labral repair time.

Outcomes of Joint Preservation Procedures for Cartilage Injuries in the Hip: A Systematic Review and Meta-analysis

Background:

The detection and management of chondral injuries of the hip, especially in a younger patient population, may preempt joint degeneration. Although the outcomes of preservation techniques have been well described for other weightbearing joints, such as the knee, evidence for hip joint preservation after procedures such as microfracture and autologous chondrocyte implantation remains in its infancy.

Purpose:

To evaluate outcomes of joint preservation procedures in the hip, including the success rate and patient-reported outcomes (PROs).

Study Design:

Systematic review; Level of evidence, 4.

Methods:

This review was performed using the terms “hip arthroscopy,” “microfracture,” “autologous chondrocyte implantation,” “fibrin glue,” “osteochondral transfer,” and variations thereof in 5 electronic databases, yielding 325 abstracts. After the application of eligibility criteria, 19 articles were included. Weighted means were calculated for PROs, and pooled estimates were calculated for age, follow-up, chondral lesion size, and success of hip preservation procedures with a random-effects proportion meta-analysis.

Results:

A total of 1484 patients (1502 hips) were identified across 19 studies (mean age, 38.0 ± 1.3 years; mean follow-up, 31.8 ± 9.6 months). Hip joint preservation techniques demonstrated a high success rate, ranging from 85.6% to 99.7%. The mean pooled chondral lesion size was 2.5 ± 0.3 cm² (95% CI, 1.9-3.0 cm²). Microfracture was the most frequent technique, utilized by 11 studies, and demonstrated an 89.6% success rate (95% CI, 82.4%-96.7%). The highest pooled success rate was exhibited by autologous membrane-induced chondrogenesis in 3 studies (99.7% [95% CI, 99.0%-100.0%]). All PROs demonstrated a statistically significant increase postoperatively, including the modified Harris Hip Score, Nonarthritic Hip Score, and Hip Outcome Score–Activities of Daily Living and Hip Outcome Score–Sports-Specific Subscale (all P < .05). The visual analog scale for pain also demonstrated a statistically significant decrease of 37.2% (P < .05).

Conclusion:

Hip preservation procedures demonstrate a high success rate, with microfracture representing the most frequently utilized cartilage preservation technique in the peer-reviewed literature. PROs significantly improved after surgery. Further investigation of hip preservation modalities with long-term follow-up is required to create evidence-based clinical recommendations and treatment algorithms.

A systematic review of surgical methods to restore articular cartilage in the hip

This systematic review examines the current literature regarding surgical techniques for restoring articular cartilage in the hip, from the older microfracture techniques involving perforation to the subchondral bone, to adaptations of this technique using nanofractures and scaffolds. This review discusses the autologous and allograft transfer systems and the autologous matrix-induced chondrogenesis (AMIC) technique, as well as a summary of the previously discussed techniques, which could become common practice for restoring articular cartilage, thus reducing the need for total hip arthroplasty. Using the British Medical Journal Grading of Recommendations, Assessment, Development and Evaluation (BMJ GRADE) system and Grade system. Comparison of the studies discussed shows that microfracture has the greatest quantity and quality of research, whereas the newer AMIC technique requires more research, but shows promise.

Cite this article: W. E. Hotham, A. Malviya. A systematic review of surgical methods to restore articular cartilage in the hip. Bone Joint Res 2018;7:336–342. DOI: 10.1302/2046-3758.75.BJR-2017-0331.