Chondral defects of the glenohumeral joint still remain a diagnostic and management challenge. Causes include acute injuries, rotator cuff tears, degenerative processes, and physical labor, as well as overhead sports.1Paley K.J. Jobe F.W. Pink M.M. Kvitne R.S. ElAttrache N.S. Arthroscopic findings in the overhand throwing athlete: evidence for posterior internal impingement of the rotator cuff., 2Ruckstuhl H. de Bruin E.D. Stussi E. Vanwanseele B. Post-traumatic glenohumeral cartilage lesions: a systematic review., 3Gross C.E. Chalmers P.N. Chahal J. et al.Operative treatment of chondral defects in the glenohumeral joint. The incidence varies between diverse groups of patients and falls between 13% to 17%.4Guntern D.V. Pfirrmann C.W. Schmid M.R. et al.Articular cartilage lesions of the glenohumeral joint: diagnostic effectiveness of MR arthrography and prevalence in patients with subacromial impingement syndrome.,5The incidence of glenohumeral joint abnormalities associated with full-thickness, reparable rotator cuff tears. Whereas there is agreement among the literature that total joint arthroplasty is a reasonable option for elderly and low-demand patients with symptomatic cartilage lesions,6Sperling J.W. Antuna S.A. Sanchez-Sotelo J. Schleck C. Cofield R.H. Shoulder arthroplasty for arthritis after instability surgery. it is still a matter of debate what treatment is most suitable for the younger and more active cohort because of the risk of hardware loosening and the higher demand of the shoulder.7Elser F. Braun S. Dewing C.B. Millett P.J. Glenohumeral joint preservation: current options for managing articular cartilage lesions in young, active patients.,8Denard P.J. Wirth M.A. Orfaly R.M. Management of glenohumeral arthritis in the young adult. Research is therefore focusing on joint-preserving methods such as arthroscopic debridement,9Richards D.P. Burkhart S.S. Arthroscopic debridement and capsular release for glenohumeral osteoarthritis. microfracture,10Frank J.K. Heuberer P.R. Laky B. Anderl W. Pauzenberger L. Glenohumeral Microfracturing of Contained Glenohumeral Defects: Mid- to Long-term Outcome. osteochondral autograft transfer11Scheibel M. Bartl C. Magosch P. Lichtenberg S. Habermeyer P. Osteochondral autologous transplantation for the treatment of full-thickness articular cartilage defects of the shoulder. or allograft transplantation,12Mitchell J.J. Vap A.R. Sanchez G. et al.Concomitant reverse Hill-Sachs lesion and posterior humeral avulsion of the glenohumeral ligament: treatment with fresh talus osteochondral allograft and arthroscopic posterior humeral avulsion of the glenohumeral ligament and labrum repair. partial shoulder resurfacing,13

Holschen M, Berg D, Schulte T, Bockmann MB, Witt KA, Steinbeck J. Arthroscopic and open partial arthroplasty for the treatment of focal grade IV cartilage defects of the humeral head [published online July 26, 2020]. Arch Orthop Trauma Surg. https://doi.org/10.1007/s00402-020-03552-x.

, 14Scalise J.J. Miniaci A. Iannotti J.P. Resurfacing arthroplasty of the humerus: indications, surgical technique, and clinical results., 15Pauzenberger L. Heuberer P. Anderl W. Partieller Oberflächenersatz beim Knorpelschaden der Schulter. and autologous chondrocyte implantation (ACI).16Boehm E. Minkus M. Scheibel M. Autologous chondrocyte implantation for treatment of focal articular cartilage defects of the humeral head. Minced cartilage implantation17

Salzmann GM, Ossendorff R, Gilat R, Cole BJ. Autologous Minced Cartilage Implantation for Treatment of Chondral and Osteochondral Lesions in the Knee Joint: An Overview [published online July 25, 2020]. Cartilage. https://doi.org/10.1177/1947603520942952.

is a technique that was first described in the early 1980s18[Closure of joint cartilage defects using cartilage fragments and fibrin glue]. but is now gaining more and more interest, especially in the field of knee surgery where first clinical trials support good outcomes.19Massen F.K. Inauen C.R. Harder L.P. Runer A. Preiss S. Salzmann G.M. One-step autologous minced cartilage procedure for the treatment of knee joint chondral and osteochondral lesions: a series of 27 patients with 2-year follow-up. It is a cost-effective procedure that brings autologous cartilage chips harvested from the defect itself, the surrounding defect wall, lose bodies, or nonweightbearing areas and brings them into the area of damage in a single-step open or arthroscopic approach.DiscussionCartilage defects of the glenohumeral joint still remain a diagnostic and management challenge. Although surgeons agree to use total joint arthroplasty as a reasonable option for elderly and low-demand patients,6Sperling J.W. Antuna S.A. Sanchez-Sotelo J. Schleck C. Cofield R.H. Shoulder arthroplasty for arthritis after instability surgery. it is still a subject of discussion regarding what joint-preserving treatment to apply for the younger and more active cohort.

The technique described here is an alternative joint-preserving approach to treat symptomatic chondral lesions and possibly also osteochondral of the glenohumeral joint through a 1-stage arthroscopic approach using minced cartilage.

Previously used joint-preserving methods such as arthroscopic debridement results in pain relief but lacks preventing the development of early-onset arthritis.23Millett P.J. Horan M.P. Pennock A.T. Rios D. Comprehensive arthroscopic management (CAM) procedure: clinical results of a joint-preserving arthroscopic treatment for young, active patients with advanced shoulder osteoarthritis. Microfracture is also considered a treatment option for patients with articular cartilage damage less than 2.5 cm. However, in radiographic findings these patients showed a progression of osteoarthritis as well.10Frank J.K. Heuberer P.R. Laky B. Anderl W. Pauzenberger L. Glenohumeral Microfracturing of Contained Glenohumeral Defects: Mid- to Long-term Outcome.Osteochondral autograft transfer is a second-line option for small defects where cylindrical grafts are harvested from nonweightbearing areas such as the intercondylar notch and are transplanted into the area of osteochondral damage. As an unusual but serious complication, donor site morbidity after arthroscopically intervention needs to be considered.24Management of cartilage defects in the shoulder.Allograft transplantation is reserved for salvage cases and is not standard of care in Europe. However, short-term results showed improved clinical outcomes in the field of knee surgery.25Williams B. Southworth T. Naveen N. et al.Clinically significant outcome achievement after osteochondral allograft surgery.Partial shoulder resurfacing is a procedure that only replaces a segment of the affected joint. This leaves more options for a potentially later necessary total arthroplasty. Recently published results suggest promising clinical outcomes during a 5-year follow-up.26Pauzenberger L. Heuberer P. Laky B. Kriegleder B. Five-year outcome of arthroscopic partial humeral head resurfacing. However, there are risks caused by hardware implantation (e.g., infection, loosening), as well as severe glenoid lesions that are presented as a contraindication for this procedure.ACI is a commonly used treatment in hip and knee surgery but is barely tested for glenohumeral chondral defects. First studies showed promising results,16Boehm E. Minkus M. Scheibel M. Autologous chondrocyte implantation for treatment of focal articular cartilage defects of the humeral head.,27Niethammer T.R. Altmann D. Holzgruber M. et al.Patient-reported and magnetic resonance imaging outcomes of third-generation autologous chondrocyte implantation after 10 years. but disadvantages such as high cost, chondral dedifferentiation and senescence, an unsuccessful growth of chondrocytes, the restriction in availability of specialized laboratories, and the 2-stage surgical design need to be taken into account. In addition, a very recent study showed that a delay from time of biopsy to implantation can lead to defect expansion.28Pettit R. Everhart J. Dibartola A. et al.Factors predicting lesion expansion in two-stage chondrocyte implantation procedures.In 1983, Albrecht et al.18[Closure of joint cartilage defects using cartilage fragments and fibrin glue]. described a method using cartilage cut into small pieces and reimplanted directly into the knees of rabbits. Later, Lu et al.29Lu Y. Dhanaraj S. Wang Z. et al.Minced cartilage without cell culture serves as an effective intraoperative cell source for cartilage repair. showed in their study from 2006 that autologous chondrocyte implantation can be achieved without the need for growing the cells under laboratory conditions beforehand. They strictly used cartilage tissue (in contrast to morselized osteochondral grafts, which consist of a sparse amount of cartilage tissue and quite large bone contribution30Surgical technique for articular cartilage transplantation to traumatic and arthritic defects in the knee joint 1701. and delivered the fragments into a nonbleeding chondral defect, which results in a repair mechanism more likely promoted by the chondrocyte itself instead of other cells (i.e., mesenchymal stem cells), which can show osteogenic potential.Also, animal studies indicate promising results for this method; there was a proven potential that implanted chondrocytes proliferate and can form a functionable cartilage that is superior to microfracture and comparable to the current gold standard ACI.31Christensen B.B. Olesen M.L. Lind M. Foldager C.B. Autologous cartilage chip transplantation improves repair tissue composition compared with marrow stimulation., 32Matsushita R. Nakasa T. Ishikawa M. et al.Repair of an osteochondral defect with minced cartilage embedded in atelocollagen gel: a rabbit model., 33Domínguez Pérez J.M. Fernández-Sarmiento J.A. Aguilar García D. et al.Cartilage regeneration using a novel autologous growth factors-based matrix for full-thickness defects in sheep.Recent studies investigating the proliferation and migration of chondrocytes in an atelocollagen gel using ACI compared to minced cartilage show beneficial outcomes for the implantation of minced cartilage. Additionally it was demonstrated that there was improved production of the cartilage matrix.34Tsuyuguchi Y. Nakasa T. Ishikawa M. et al.The benefit of minced cartilage over isolated chondrocytes in atelocollagen gel on chondrocyte proliferation and migration. Another point of concern using ACI for osteochondral damages in joints is the implantation of chondrocytes lacking their surrounding microenvironment, the pericellular matrix. Among others consisting of type VI collagen,35Rothdiener M. Uynuk-Ool T. Sudkamp N. et al.Human osteoarthritic chondrons outnumber patient- and joint-matched chondrocytes in hydrogel culture-Future application in autologous cell-based OA cartilage repair?. it forms a functional unit with the enclosed chondrocyte and is then called the “chondron.” It was shown before that the pericellular matrix is crucial for behavior and survival of the enclosed chondrocyte, which is consistent with the findings from Rothdiener et al.35Rothdiener M. Uynuk-Ool T. Sudkamp N. et al.Human osteoarthritic chondrons outnumber patient- and joint-matched chondrocytes in hydrogel culture-Future application in autologous cell-based OA cartilage repair?. who revealed that cultured chondrons outperform chondrocytes regarding cell number, survival, collagen type II synthesis, the mRNA expression of phenotype-relevant genes, and the expression of enzymatically active GAPDH protein. Using minced cartilage, viable chondrocytes are transferred into the defect site at a high number, where outgrowth is promoted of these embedded cells by increasing the surface area resulting from fragmentation.36Salzmann G.M. Nuernberger B. Schmitz P. et al.Physicobiochemical synergism through gene therapy and functional tissue engineering for in vitro chondrogenesis.As a source for harvesting the needed cartilage, it was shown that samples collected from the center of a cartilage lesion appeared to have lower qualities containing chondrocytes less viable and with inferior ability to form cartilage as compared to the closely flanking peripheral areas.37Acevedo L. Iselin L. Berkelaar M.H.M. et al.Comparison of human articular cartilage tissue and chondrocytes isolated from peripheral versus central regions of traumatic lesions. If not enough material is available, cartilage can be taken from nonweightbearing areas as shown in the knee, for example, from the intercondylar notch.38Niemeyer P. Pestka J.M. Kreuz P.C. et al.Standardized cartilage biopsies from the intercondylar notch for autologous chondrocyte implantation (ACI). However Aurich et al.39Aurich M. Hofmann G.O. Best N. Rolauffs B. Induced redifferentiation of human chondrocytes from articular cartilage lesion in alginate bead culture after monolayer dedifferentiation: an alternative cell source for cell-based therapies?. demonstrated an inferior redifferentiation potential of chondrocytes harvested from these areas when compared to the cells from the margins of the defects.There are 2 ways to approach mincing the collected cartilage: first is to chop it with a sharp, frequently renewed scalpel on a stable, clean ground. Second is to use custom-made devices that automatically produce fragments in the recommended size. The latter is an efficient, time-saving way to finely cut the cartilage; however, both techniques show similar outgrowth potential and matrix deposition under laboratory conditions.40Levinson C. Cavalli E. Sindi D.M. et al.Chondrocytes from device-minced articular cartilage show potent outgrowth into fibrin and collagen hydrogels.For fixation of the minced cartilage, several methods containing the use of hydrogels with or without membrane coverage and potentially augmented by PRP/platelet-poor plasma are described in literature so far.41Christensen B.B. Foldager C.B. Olesen M.L. Hede K.C. Lind M. Implantation of autologous cartilage chips improves cartilage repair tissue quality in osteochondral defects: a study in Gottingen minipigs., 42Salzmann G.M. Calek A.K. Preiss S. Second-generation autologous minced cartilage repair technique., 43Brittberg M. Lindahl A. Nilsson A. Ohlsson C. Isaksson O. Peterson L. Treatment of deep cartilage defects in the knee with autologous chondrocyte transplantation. Since it was shown that chondrocytes function best in the absence of any primary fixation methods and disturbances after implantation,44Walter S.G. Ossendorff R. Schildberg F.A. Articular cartilage regeneration and tissue engineering models: a systematic review. a purely autologous technique was preferred with PRP used as the biological agent. The fibrinogen and a finally autologous-produced thrombin solution eventually form a stable clot. It was recently shown in a cadaver knee model that this method leads to a robust construct as long as the fibrin level is not applied too liberally.45Bogunovic L. Wetters N.G. Jain A. Cole B.J. Yanke A.B. In vitro analysis of micronized cartilage stability in the knee: effect of fibrin level, defect size, and defect location. Domínguez Pérez et al.33Domínguez Pérez J.M. Fernández-Sarmiento J.A. Aguilar García D. et al.Cartilage regeneration using a novel autologous growth factors-based matrix for full-thickness defects in sheep. demonstrated in a sheep model that the minced cartilage particles showed good repair with platelet-poor plasma and PRP with mature chondrons and a matrix containing collagen fibers in a similar distribution and intensity as the flanking healthy cartilage.Clinical trials of the minced cartilage procedure are still rare and restricted to the knee joint so far. The few published studies show good clinical outcomes and evaluate it as a safe and effective method that results in good cartilage repair.19Massen F.K. Inauen C.R. Harder L.P. Runer A. Preiss S. Salzmann G.M. One-step autologous minced cartilage procedure for the treatment of knee joint chondral and osteochondral lesions: a series of 27 patients with 2-year follow-up.,46Christensen B.B. Foldager C.B. Jensen J. Lind M. Autologous dual-tissue transplantation for osteochondral repair: early clinical and radiological results.,47Cole B.J. Farr J. Winalski C.S. et al.Outcomes after a single-stage procedure for cell-based cartilage repair: a prospective clinical safety trial with 2-year follow-up.In 2011, Cole et al.47Cole B.J. Farr J. Winalski C.S. et al.Outcomes after a single-stage procedure for cell-based cartilage repair: a prospective clinical safety trial with 2-year follow-up. compared the 2-year outcome of a scaffold-based minced cartilage procedure with microfracture in a randomized controlled trial. They reported a similar outcome of the 2 groups with the MRI data and standardized outcomes assessment tools indicating that this minced cartilage procedure is a safe and feasible method to treat medium-sized, focal cartilage defects in the knee.Christensen et al.46Christensen B.B. Foldager C.B. Jensen J. Lind M. Autologous dual-tissue transplantation for osteochondral repair: early clinical and radiological results. studied the outcome of the use of combined autologous bone and cartilage chips for treating osteochondritis dissecans lesions, where the defects were filled with bone and covered with minced cartilage from the intercondylar notch embedded in fibrin glue. Analysis of the MRI and computed tomography scans and the clinical scores 1 year after surgery showed very good subchondral bone restoration and good cartilage repair. Also patient outcome showed significant improvements suggesting this method is a promising, low-cost treatment option for osteochondral injuries.46Christensen B.B. Foldager C.B. Jensen J. Lind M. Autologous dual-tissue transplantation for osteochondral repair: early clinical and radiological results.More frequently used in the United States, particulated juvenile articular cartilage represents another single-step procedure for chondral joint lesions using juvenile allograft chondral chips, which may have increased proliferative and restorative potential.48Riboh J.C. Cole B.J. Farr J. Particulated articular cartilage for symptomatic chondral defects of the knee. Research undertaken so far shows good results; however, reports are scarce and thus lack a high level of evidence.The most recent study from Massen et al.19Massen F.K. Inauen C.R. Harder L.P. Runer A. Preiss S. Salzmann G.M. One-step autologous minced cartilage procedure for the treatment of knee joint chondral and osteochondral lesions: a series of 27 patients with 2-year follow-up. prospectively evaluated the 2-year clinical and radiological outcomes after the treatment of chondral and osteochondral knee joint lesions by a single-step autologous minced cartilage procedure. They reported positive results in knee function, pain, and satisfaction.19Massen F.K. Inauen C.R. Harder L.P. Runer A. Preiss S. Salzmann G.M. One-step autologous minced cartilage procedure for the treatment of knee joint chondral and osteochondral lesions: a series of 27 patients with 2-year follow-up.Schneider et al.49Schneider S. Ossendorff R. Holz J. Salzmann G.M. Arthroscopic minced cartilage implantation (MCI): a technical note. recently introduced this method as third-generation minced cartilage implantation via an all-arthroscopic approach in the field of knee surgery. However, further clinical data, especially with regard to long-term follow-up, are still required.To provide a more distinctive view on the benefits of this procedure, especially in comparison to the available alternatives for glenohumeral chondral defects, studies with long-term follow-up and larger cohorts will be needed. All the pearls and pitfalls of this technique are listed in Table 1, and the advantages and disadvantages are listed in Table 2.

Table 1Pearls and Pitfalls of the Minced Cartilage Procedure

ACP, Autologous conditioned plasma.

Table 2Advantages and Disadvantages of the Minced Cartilage Procedure