Introduction

Focal cartilage damage to the patellofemoral (PF) joint often results in pain and disability. Due to the anatomical complexity of this joint, the therapeutic success after cartilage repair is often less than in other areas of the knee joint. The current case shows a patient with cartilage damage in the trochlea and on the opposite patella surface, a so-called "kissing lesion" and describes the chosen therapeutic approach.

Content

CASE HISTORY The 31-year-old patient hit his left kneecap in a bicycle fall and suffered PF cartilage damage. Intensive physiotherapy for 8 months and intra-articular corticosteroid injections failed to alleviate the pain. In addition, joint blockages and a tendency to swelling persisted. Due to severe impairment at work and sport, the patient decided to have surgery. On clinical examination he showed a slightly swollen knee with a normal range of motion, stable cruciate and collateral ligaments and symmetrical muscles and a normal leg axis in both legs.

PRE-OPERATIVE IMAGING: X-ray showed a straight leg axis. MRI showed a kissing lesion in the medial PF joint with a larger, full-thickness trochlear defect and a smaller grade II patellar defect. A modified AMIC® technique was chosen as therapy due to the patient's age, size and localization of the cartilage lesion. This included a) the recruitment of stem cells by microdrilling of the subchondral bone and the addition of platelet-rich fibrin (PRF) and b) an increase in the number of differentiated cells (chondrocytes) in the defect by loading the membrane with cartilage chips ("minced cartilage").

SURGICAL STEPS

Taking blood to obtain PRF: 60 ml of sterile venous blood was taken and centrifuged for about 30 min. The PRF was then pipetted off.

Defect preparation and cartilage harvest: A ring curette was used to remove loose and damaged cartilage tissue in the trochlear defect down to the subchondral bone plate. In order to obtain a vertical and stable defect shoulder, a small amount of cartilage was removed from the edge of the defect with a scalpel and used for the subsequent preparation of cartilage chips.

Microdrilling for recruitment of stem cells: The sclerotic bone was removed with a high-speed milling machine under water cooling and then the subchondral bone was perforated at a distance of 3 mm with a 1.6 mm K-wire to a depth of 1–1.5 cm. The opposite defect on the patella was prepared in the same way.

On arthroscopic examination, the patellar defect was larger than shown on the MRI and was therefore also treated. Cruciate ligaments, menisci, and cartilages of the tibiofemoral compartments were intact.

Prepare the Chondro-Gide® membrane: The defect shape and size was determined using an aluminum template and the membrane was cut to size when dry. A 10-15% increase in size when wet was taken into account. The membrane was then hydrated with the calcium-activated PRF.

Loading of the membrane with cartilage chips: The cartilage fragments taken from the defect edge were chopped up with a scalpel into approx. 1 mm3 large pieces and loaded onto the porous side of the hydrated membrane and fixed with fibrin glue. The loaded membrane was then soaked again with PRF.

PRF injection into the subchondral bone: The PRF was injected into the deep subchondral bone zone through the individual microdrilling channels. PRF modulates subchondral bone inflammation and stimulates stem cell migration into the defect. These are chondro-inductive, stimulate the proliferation of local chondrocytes through cell-cell interaction and thus accelerate tissue regeneration.

Implanting the loaded membrane: After applying the fibrin glue in the defect, the membrane was implanted with the loaded side facing the defect. The membrane offers the regenerate the necessary primary stability and supports the formation of new cartilage.

Fixation of the Collagen membrane: Due to the high shear stress at a corresponding PF defect, the collagen membrane was sewn into the two defects with 6-0 sutures. Finally, the edge and the sutures were sealed with fibrin glue. In the PF joint in particular, it is important to prevent the membrane from shearing out.

REHABILITATION: Initial relief on crutches and restriction of knee flexion with an orthosis. Sole contact and passive flexion up to 30° (by CPM/physiotherapist) were allowed in the first 2 weeks. Partial weight bearing and range of motion were then continuously increased and after 6 weeks full weight bearing and free movement of the knee were allowed again.

FOLLOW-UP: After three months, the patient was absolutely pain-free, could fully bear weight on the knee and move it without restriction. He showed good sensorimotor function and no apparent muscle deficit. The final 6-month MRI showed a well-integrated cartilage reconstruction in the trochlea and patella, flush with the adjacent cartilage. The subcortical bone marrow edema of the medial patellar facet had regressed and was still slightly present in the trochlear area. The T2 relaxation time was only slightly increased.

References

Levinson C, et al., Chondrocytes From Device-Minced Articular Cartilage Show Potent Outgrowth Into Fibrin and Collagen Hydrogels. Orthop J Sports Med. 2019 Sep 10;7(9):2325967119867618.

Krüger JP, et al., Human platelet-rich plasma stimulates migration and chondrogenic differentiation of human subchondral progenitor cells. J Orthop Res. 2012 Jun;30(6):845-52.

de Windt TS, et al., Direct Cell-Cell Contact with Chondrocytes Is a Key Mechanism in Multipotent Mesenchymal Stromal Cell-Mediated Chondrogenesis. Tissue Eng Part A. 2015 Oct;21(19-20):2536-47.

Kim M, et al., Extracellular vesicles mediate improved functional outcomes in engineered cartilage produced from MSC/chondrocyte cocultures. Proc Natl Acad Sci U S A. 2019 Jan 29;116(5):1569-1578.

Steinwachs MR, et al., Systematic Review and Meta-Analysis of the Clinical Evidence on the Use of Autologous Matrix-Induced Chondrogenesis in the Knee. Cartilage. 2019 Sep 11:1947603519870846.

Steinwachs MR, et al., Enhanced Cartilage Repair Technique with K-Wire Drilling Plus Subchondral Injected Plasma Rich in Growth Factors – A New Modified Microfracture Technique. J Surg. 2020; 5: 1275

Acknowledgments

no

Introduction

Introduction

Injuries to the knee joint, like surgical therapies, lead to a significant restriction of motor joint functions. Early functional passive and active movement therapy is recommended to restore motor skills. In addition to passive manual movement therapy, power-assisted therapeutic movement splints have also been used for various indications for years. Basic scientific research into CPM therapy (continuous passive motion) began in the 1970s. Since the 1980s, CPM therapy has been used, initially in the inpatient area for immediate post-operative follow-up treatment with various purposes. In the early 1990s, the use of joint motion splints was introduced into outpatient care. Since then, such motor-driven movement splints have been prescribed as an aid, so that patients can also complete passive movement therapy at home on these CPM splints for several hours a day. Ensuring early functional mobilization has been a key focus after surgical interventions on joints since the 1990s and contributes significantly to the success of the therapy. Although the use of CPM is recognized in the medical literature, there are currently no guidelines from a German specialist society for defined CPM therapy in the knee joint.

The scientific basis of this CPM therapy is based on the 1994 by Dr. Salter published studies «The Physiologic Basis of Continuous Passive Motion for Articular Cartilage Healing and Regeneration. In it he presents his experiences after 23 years of basic research and 15 years of clinical practice.

The goal of Dr. Salter was to regenerate the cartilage. He performed the basic experimental work on a rabbit animal model. It was shown that the CPM therapy was well tolerated and significant, stimulating effects on the articular cartilage and extra-articular structures were detectable, adhesions and joint stiffening could be prevented and the regeneration of articular cartilage through neochondrogenesis was stimulated. Clinical applications then also showed that the hospital stay and the rehabilitation time could be reduced by CPM treatment.This led to a paradigm shift in the 1980s and 1990s with the development of early functional rehabilitation treatment. The CPM treatment became an integral part of the postoperative treatment of the newly developed cartilage regenerative surgical techniques (Brittberg et al. 1994, Steadman et al. 2002, Hangody et al.2008, Kon E et al. 2011, Knutsen et al. 2016, Saris et al 2018). In the majority of published RCTs related to cartilage regeneration, CPM treatment was performed during rehabilitation.

Content

Results:

In experimental studies, the negative aspects of joint immobilization after trauma and surgical therapies on cartilage metabolism and joint homeostasis could also be proven. (Sakamoto J et al. 2009) In addition, recent studies also show the positive effect of CPM therapy on the chondrogenic biosynthesis of PRG4 (Nugent-Derfus GE et al. 2007) and anti-inflammatory effects on the joint (Ferretti M et al. 2005). Despite a large number of positive effects of CPM therapy, Fazalare J and co-authors were unable to prove any valid clinical evidence (only 4 studies) in their systematic review in their final conclusions regarding the benefit of CPM therapy postoperatively in knee cartilage surgery due to the great heterogeneity of the studies.Unfortunately, despite an overwhelming body of fundamental scientific work and the current clinical practice of implementing continuous passive movement postoperatively in knee cartilage repair procedures, a corresponding number of methodological high-quality studies are lacking (Fazalare J et al. 2010). In the review by Goosmann et al. 2019, seven clinical studies (ØRCTs) and 3 reviews on the use of CPM after cartilage repair surgery were included in the literature analysis. The current study situation is characterized by great heterogeneity. The available studies show that the use of CPM after cartilage repair surgery resulted in good defect filling, good results in the questionnaires on knee stability, activity, quality of life and functionality, and a reduction in pain and swelling could be proven. Although CPM therapy has a major benefit according to the majority of experts, the level of evidence must be classified as low due to inhomogeneous studies.

In the systematic literature review by Rogan S et al. 2013, a review and ten original papers were included for further evaluation. The included studies showed methodological weaknesses. Heterogeneity in outcome measures and the fact that 6 of 9 studies with a one-group pre-post design measured the combined effect of surgical treatment and CPM precluded a meta-analysis. The authors were only able to document significant improvements in subjective outcomes such as pain, swelling, Quality Life Survey, Knee Society Score, WOMAC Score or Rating Cincinnati in only three studies as a result of surgical treatment and the use of CPM therapy postoperatively. Six (case) studies indicated improved cartilage quality in patients after CPM. The authors recommend more high-quality randomized controlled trials to provide high-level evidence.

Conclusion:

The CPM therapy is an important part of postoperative treatment after cartilage regenerative therapy. Experimentally, an improved metabolism and vitality of the cartilage cells, a reduction in inflammatory metabolites, improved regeneration filling and differentiation as well as a reduction in pain and swelling can be demonstrated in experimental and clinical studies. Due to the study heterogeneity and the low methodological study quality, there is a low level of evidence for CPM therapy and a need for RCT´s.

The use of CPM therapy is indicated according to the current health care standard (G-BA) if a range of motion of the affected joint that is relevant to everyday life is only possible through the additional use, despite regular physical therapy measures (especially physiotherapy) and the patient’s learned exercises of these rails can be reached. Furthermore, the therapy can be used if the postoperative follow-up treatment requires a longer restriction of mobility with joint relief to achieve the therapy goal. (cartilage repair)

References

no reference

Acknowledgments

no