Magnetic resonance imaging and clinical evaluation of patellar resurfacing with press-fit osteochondral autograft plugs

Assessment of Patellar Vascularity after Patellar Cartilage Restoration via Lateral Parapatellar Approach: Analysis Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

OBJECTIVE

Patellofemoral cartilage restoration procedures, including osteochondral allograft, particulated juvenile cartilage, and matrix-induced autologous chondrocyte implantation, have been shown to be effective treatments for patellofemoral cartilage lesions. However, concerns exist regarding disruption of the patellar vascular supply and secondary stabilizers of the patellofemoral joint during medial parapatellar approaches, especially when combined with a lateral release. A lateral parapatellar approach affords the possibility of avoiding disruption of the medial blood supply to the patella, while also allowing laterally-based soft tissue stabilization procedures. The purpose of this study was to investigate in vivo changes in patellar vascularity following patellofemoral cartilage restoration procedures performed via a lateral parapatellar approach via use of dynamic contrast-enhanced magnetic resonance (MR) imaging.

DESIGN

This study is a prospective case series of 5 adult patients undergoing patellofemoral cartilage restoration procedures via a lateral parapatellar approach with pre-operative and post-operative dynamic contrast-enhanced MR imaging to assess changes in patellar vascularity. Secondary outcomes included knee range of motion, need for revision surgery, and complications.

RESULTS

There was no significant post-operative difference in patellar vascularity in patients undergoing patellofemoral cartilage restoration procedures via a lateral parapatellar approach, as evaluated by qualitative MR imaging.

CONCLUSION

Our results suggest that a lateral parapatellar approach for cartilage restoration procedures may preserve patellar vascularity, while also allowing for lateral release to be performed through the same incision.

Cartilage Restoration for Isolated Patellar Chondral Defects: An Updated Systematic Review

Background

Patellar chondral lesions can be particularly challenging to manage in younger and more active populations.

Purpose

To synthesize, organize, and summarize the results and complication rates of various patellar cartilage restoration techniques.

Study Design

Systematic review; Level of evidence, 4.

Methods

We performed this systematic review according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using the Medline, Embase, Scopus, and Cochrane databases. Studies were included that reported on surgical treatment of patellar chondral defects with ≥5 patients and 12 months of follow-up data. Relevant demographic data from the included studies were extracted, and patient-reported outcome scores, visual analog scale for pain results, return-to-sport rate, complications, and concomitant procedures were documented.

Results

There were 24 studies that met the inclusion criteria, with a total of 575 patients (male, n = 239; female, n = 336). In total, 6 surgical techniques were utilized. In 9 studies, the surgical procedure of choice was osteochondral autograft transplantation (OAT); 8 studies evaluated autologous chondrocyte implantation (ACI); 3 evaluated advanced microfracture/autologous matrix-induced chondrogenesis; 1 evaluated osteochondral allograft transplantation (OCA); 1 evaluated particulate juvenile articulated cartilage; and 2 evaluated a synthetic osteochondral graft. No uniform functional outcome score or assessment was utilized across studies. OAT was predominantly used for smaller chondral lesions (<2 cm²) and demonstrated minimal complication rates and satisfactory outcome scores. Advanced microfracture techniques showed promise, with improvement in outcome scores and zero complications. Matrix-induced ACI consistently exhibited higher mean improvement in the measured outcome scores and resulted in fewer complications when compared with previous generations of ACI.

Conclusion

OAT and ACI were the most studied procedures for isolated patellar chondral defects. Advanced microfracture techniques showed promise, but indications (ie, size) and variability in techniques need to be elucidated in higher-level studies. Further prospective studies comparing OCA and matrix-induced ACI for larger patellar defects are necessary to determine the superior technique.

The influence of primary treatment approach on outcomes in patients with osteochondral fracture after patellar dislocation: a case series

BACKGROUND

We characterized the relation of primary treatment approaches to the need of later surgical interventions and the outcomes of patellar dislocation in patients with patellofemoral osteochondral fracture (OCF).

METHODS

Overall, 134 patients with OCF were categorized in two groups according to treatment approach: primary surgery (operation within 90 days from injury) and conservative treatment. Data on surgical procedures, OCF characteristics, and patellofemoral anatomy were retrospectively collected. To measure subjective outcomes, 54 patients completed the knee-specific patient-reported outcome measures (PROMs) Kujala score, Tegner activity scale, the knee injury and osteoarthritis outcome score (KOOS) quality of life (QoL) subscale, and visual analog scale pain items.

RESULTS

The mean follow-up time was 4.9 years [standard deviation (SD) 2.7 years]. The primary treatment approach was surgery in 73 patients (54%) and conservative in 61 patients (46%) of whim 18 (30%) needed late surgery. Of primary surgery patients, the OCF was reimplanted in 45 patients (62%) and removed in the rest. Of all patients, 31 needed surgery in the later phase after the primary treatment approach (either reoperation or surgery after insufficient outcome of conservative treatment). In conservatively treated patients, OCF was smaller and patellofemoral joint malformation was more severe than in surgery group. Among patients who completed the PROMs, the outcomes appeared generally acceptable in both groups.

CONCLUSIONS

Although a majority of the primary treatment approaches for OCF after patellar dislocation were definitive, one-fourth of patients required surgery in the later phase. PROMs did not indicate major differences between the study groups.

Osteochondral Allograft Transplant for Combined Medial and Lateral Patellar Cartilage Lesions: The Osteochondral Wide Lesion (OWL) Technique

Symptomatic articular cartilage injuries are often seen in young active patients and athletes. Magnetic resonance imaging screening examinations have frequently identified such lesions in athletic patients. Patellofemoral chondral defects were previously identified as the most common knee cartilage lesion in high-level athletes. Chondral defects measuring 2 cm² or greater and complex cartilage defects involving bone loss are ideally replaced with fresh osteochondral allograft. We describe a technique indicated for patients with symptomatic and recurrent anterior knee pain associated with osteochondral patellar defects including the lateral and medial patellar facets. Patients who have undergone previous interventions, including membrane techniques, microfracture, or autologous chondral transplantation, without clinical benefit are also eligible to undergo osteochondral allograft transplantation for combined medial and lateral patellar cartilage lesions, that is, the osteochondral wide lesion (OWL) technique.

Good clinical outcomes after patellar cartilage repair with no evidence for inferior results in complex cases with the need for additional patellofemoral realignment procedures: a systematic review

PURPOSE

Focal, patellar cartilage defects are a challenging problem as most cases have an underlying multifactorial pathogenesis. This systematic review of current literature analysed clinical results after regenerative cartilage repair of the patella with a special focus on the assessment and treatment of existing patellofemoral malalignment.

METHODS

A systematic review was conducted to identify articles reporting clinical results after cartilage regenerative surgeries of the patella using the PubMed and Scopus database. The extracted data included patient-reported outcome measures (PROMS) and whether cartilage repair was performed alone or in combination with concomitant surgeries of underlying patellofemoral co-pathologies. In cases of isolated cartilage repair, specific exclusion criteria regarding underlying co-pathologies were screened. In cases of concomitant surgeries, the type of surgeries and their specific indications were extracted.

RESULTS

A total of 35 original articles were included out of which 27 (77%) were cohort studies with level IV evidence. The most frequently used technique for cartilage restoration of the patella was autologous chondrocyte implantation (ACI). Results after isolated cartilage repair alone were reported by 15 (43%) studies. Of those studies, 9 (60%) excluded patients with underlying patellofemoral malalignment a priori and 6 (40%) did not analyse underlying co-pathologies at all. Among the studies including combined surgeries, the most frequently reported concomitant procedures were release of the lateral retinaculum, reconstruction of the medial patellofemoral ligament (MPFL), and osteotomy of the tibial tubercle. In summary, these studies showed lower preoperative PROMS but similar final PROMS in comparison with the studies reporting on isolated cartilage repair. The most frequently used PROMS were the IKDC-, Lysholm- and the Modified Cincinnati Score.

CONCLUSION

This comprehensive literature review demonstrated good clinical outcomes after patellar cartilage repair with no evidence of minor results even in complex cases with the need for additional patellofemoral realignment procedures. However, a meaningful statistical comparison between isolated patellar cartilage repair and combined co-procedures is not possible due to very heterogeneous patient cohorts and a lack of analysis of specific subgroups in recent literature.

LEVEL OF EVIDENCE

Level IV.

Cartilage Restoration of Patellofemoral Lesions: A Systematic Review

PURPOSE

This study aimed to systematically analyze the postoperative clinical, functional, and imaging outcomes, complications, reoperations, and failures following patellofemoral cartilage restoration surgery.

METHODS

This review was conducted according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). PubMed, EMBASE, and Cochrane Library databases were searched up to August 31, 2018, to identify clinical studies that assessed surgical outcomes of patellofemoral cartilage restoration surgery. The Methodological Index for Non-Randomized Studies (MINORS) was used to assess study quality.

RESULTS

Forty-two studies were included comprising 1,311 knees (mean age of 33.7 years and 56% males) and 1,309 patellofemoral defects (891 patella, 254 trochlear, 95 bipolar, and 69 multiple defects, including the patella or trochlea) at a mean follow-up of 59.2 months. Restoration techniques included autologous chondrocyte implantation (56%), particulated juvenile allograft cartilage (12%), autologous matrix-induced chondrogenesis (9%), osteochondral autologous transplantation (9%), and osteochondral allograft transplantation (7%). Significant improvement in at least one score was present in almost all studies and these surpassed the minimal clinically important difference threshold. There was a weighted 19%, 35%, and 6% rate of reported complications, reoperations, and failures, respectively. Concomitant patellofemoral surgery (51% of patients) mostly did not lead to statistically different postoperative outcomes.

CONCLUSION

Numerous patellofemoral restoration techniques result in significant functional improvement with a low rate of failure. No definitive conclusions could be made to determine the best surgical technique since comparative studies on this topic are rare, and treatment choice should be made according to specific patient and defect characteristics.

LEVEL OF EVIDENCE

Level IV, systematic review of level II to IV studies.

Management of Chondral Defects Associated with Patella Instability

Cartilage defects of the patellofemoral joint are commonly found in association with patellar instability owing to abnormal biomechanics. Strategies to address chondral defects of the patellofemoral joint secondary to instability should first address causes of recurrent instability. Most patellofemoral chondral defects associated with instability are less than 2 cm2 and do not generally require intervention beyond chondroplasty. Larger defects of the patella and/or the trochlea can be repaired with osteochondral or surface cartilage repair.

Patellofemoral joint degeneration: A review of current management

The patellofemoral component of the knee joint is affected by a wide range of degenerative causes without involving the other parts of the knee. It is often the presenting pathology in early knee osteoarthritis and missed due to a variable presentation. Accurate examination and focused investigation can help with early diagnosis and guide treatment. Various aspects to treatment need to be addressed after thorough evaluation. Guidelines to approach the multifactorial pathology of the patello-femoral joint are provided with focus on the degenerative component of disease.

Clinical and Radiographic Outcomes After Treatment of Patellar Chondral Defects: A Systematic Review

CONTEXT

There is currently no evidence-based consensus on how to treat a full-thickness, symptomatic articular cartilage injury of the patella, although numerous treatment options are available.

OBJECTIVE

To systematically evaluate the functional outcomes after operative treatment of patellar cartilage lesions. Our secondary purpose was to evaluate radiographic outcomes after treatment.

DATA SOURCES

PubMed, Cochrane, and Embase.

STUDY SELECTION

Studies published between January 1, 1990 and December 31, 2018 that included patient-reported functional outcomes for patients after operative treatment of patellar chondral defects at a minimum 2-year follow-up were included.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

MINORS (Methodological Index for Non-Randomized Studies) score, level of evidence, sample size, demographic data, follow-up data, intervention, functional outcome scores, and magnetic resonance imaging (MRI) data were collected.

RESULTS

The review identified 10 studies and 293 patients receiving cartilage restoration procedures for patellar chondral defects with extractable clinical and radiographic results and data on complications and reoperations. All treatments (autologous chondrocyte implantation [ACI], matrix-induced ACI [MACI], autologous osteochondral transplantation [AOT]) utilized in the management of patellar chondral lesions, with the exception of isolated particulated juvenile articular cartilage, demonstrated statistically significant improvements in functional outcome scores compared with preoperative measurements at a minimum of 2-year follow-up. Postoperative MRIs were obtained in 6 studies and found that regardless of treatment, moderate-to-complete infill of patellar cartilage lesions was seen in the majority of patients. While failure rates were low for the various treatment modalities, rates of reoperation were substantial, with up to 40% to 60% reoperation rate seen after ACI.

CONCLUSION

Patients treated with ACI, MACI, and AOT all demonstrated statistically significant improvements in functional outcome scores with radiographic evidence of healing at minimum of 2-year follow-up. Evidence is insufficient to recommend one particular treatment over another.

Bipolar Osteochondral Allograft Transplantation of the Patella and Trochlea

OBJECTIVE

To evaluate clinical, functional, and radiographic outcomes of patients who underwent bipolar osteochondral allograft transplantation (OCAT) of the patellofemoral joint (PFJ).

DESIGN

Prospectively collected data on 18 knees who underwent fresh osteochondral allograft transplantation of the patella and trochlea by a single surgeon were reviewed. Inclusion criteria were: high-grade chondral lesions of PFJ (5 knees), or recurrent patella dislocations with trochlear dysplasia and chondral injury to the patella and/or trochlea (13 knees). Functional scores were obtained preoperatively and at follow-up appointments included Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC), Oxford, Cincinnati, Tenger-Lysholm, visual analogue scale (VAS)-pain, and Single Assessment Numeric Evaluation (SANE). Grafts were also evaluated using Osteochondral Allograft MRI Scoring System (OCAMRISS).

RESULTS

Three patients were lost to follow-up, leaving 4 knees in group 1, and 11 knees in group 2. Average age was 28.9 years (range 16-52 years). The average follow-up was 33.2 months (range 12-64 months). There was significant improvement of KOOS (from 38.7 to 83.1), IKDC (from 28.2 to 76.6), Tegner-Lysholm (from 38.3 to 88.3), Oxford (from 22.7 to 42.9), Cincinnati (from 35.1 to 83.6), VAS (from 71 to 17.9.), and SANE (from 43.3 to 83) (P < 0.0001). The OCAMRISS score for patella was 2.23 and for trochlea 4.69. There were no revisions or conversions to arthroplasty.

CONCLUSION

Bipolar OCAT of the patella and trochlea provide significant improvement in functional outcomes, relief from pain, activity level, and prevent recurrent instability.

Osteochondral Autologous Transplantation for Treating Patellar High-Grade Chondral Defects: A Systematic Review

Background:

Patellar cartilage defects account for 34.6% of defects found during routine arthroscopy. These defects pose a challenge in orthopaedic surgery because they have been associated with worse outcomes after surgical repair compared with other chondral lesions within the knee.

Purpose:

To systematically review the literature for evidence on results of osteochondral autologous transplantation (OAT) for the management of isolated patellar cartilage high-grade defects (International Cartilage Repair Society [ICRS] grade 3-4).

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review of the literature was performed to find studies that addressed outcomes regarding OAT to treat patellar high-grade cartilage defects (ICRS grade 3-4). Studies addressing patient-reported outcomes, return to sports, or magnetic resonance imaging (MRI) at follow-up after isolated OAT procedures for patellar cartilage defects were included.

Results:

A total of 5 studies were included in this review. We were not able to perform a meta-analysis as no studies had available data. A total of 102 patients who received an isolated OAT for a patellar chondral defect were included in these 5 studies. All patients showed significant improvement at final follow-up based on the following patient-reported outcome scores: Lysholm, International Knee Documentation Committee, Kujala, Tegner, and 36-Item Short Form Health Survey. We found that 4 studies used MRI during the first postoperative year to assess osteochondral plug integration and positioning. The results demonstrated that most plugs were integrated and correctly positioned when evaluated at follow-up, conducted on average after 12 months. Whether patients were able to return to sports was queried in 2 of the included studies, revealing that patients could return to their previous level in most cases (Tegner score, 5-9 at 2 years after surgery).

Conclusion:

Results indicate that OAT is a safe and reliable technique to treat patellar high-grade osteochondral defects, allowing for significant improvement in patient-reported outcomes and return to sports.

Autologous Osteochondral Transplantation in Full-thickness Patella Chondral Lesion: A Case Series

Purpose

Autologous osteochondral transplantation (AOT) in the focal cartilage lesion of the patella has been reported with less successful results compared with other sites. The purposes were to investigate the clinical outcomes of AOT for focal patellar chondral lesion without patellofemoral instability.

Methods

Between 2001 and 2007, six patients (five males and one female) with a focal patellar cartilage lesion without patellofemoral malalignment and instability were treated with AOT. The mean age was 38 (27-51) years. Intraoperatively, the size and location of lesion were assessed by international cartilage repair society classification. Lysholm score was investigated preoperatively, at 6 months, 1- and 2-year, and final follow-up. Mean follow-up period was 51 months (24-101). Transplanted grafts were evaluated by magnetic resonance imaging (MRI) and second-look arthroscopy.

Results

The mean size was 133mm2(78-225). All six cases improved at final follow-up (Lysholm score 79-100). Although immediate pain relief obtained in four cases, severe pain was persistent in remaining two cases during the 1styear and gradually relieved by 2 years following surgery. The size of these two cases was significantly larger (over 170 mm2) than that of four cases (100 mm2 in average) (P<0.05), and their locations were apart from center of the patella inspite of four cases localized centrally (P<0.05). Repaired cartilage did not show any difference by MRI and arthroscopically.

Conclusion

AOT in focal patellar chondral lesions without patellofemoral malalignment showed excellent results. In cases of large off-centeredlesions, however, it took longer for pain relief following AOT.

Patellofemoral Cartilage Lesions Treated With Particulated Juvenile Allograft Cartilage: A Prospective Study With Minimum 2-Year Clinical and Magnetic Resonance Imaging Outcomes

PURPOSE

To analyze the functional outcomes of patients treated with particulated juvenile articular cartilage (PJAC) for symptomatic articular cartilage lesions in the patellofemoral joint, correlates clinical outcomes with magnetic resonance imaging (MRI) appearance of the repair tissue using cartilage-sensitive quantitative T2-mapping.

METHODS

All patients treated with PJAC for patellofemoral lesions were identified and prospectively followed with clinical outcome scores (International Knee Documentation Committee [IKDC], Knee Outcome Survey-Activities of Daily Living [KOS-ADL], and Marx Activity Scale [MAS]). Postoperative MRI scans using quantitative T2 mapping were obtained and interpreted by an independent musculoskeletal radiologist.

RESULTS

Twenty-seven patients treated with PJAC for 30 full-thickness patellofemoral cartilage lesions were identified; mean postoperative follow-up was 3.84 years. Improvements from pre- to postoperative mean IKDC (45.9 vs 71.2, P < .001) and KOS-ADL (60.7 vs 78.8, P < .001) scores were observed; no significant change in MAS was seen (7.04 vs 7.17, P = .97). Advanced age, history of previous surgery, lesion location (patella vs trochlea), or concomitant tibial tubercle osteotomy did not affect outcome scores. Greater body mass index was associated with less improvement in KOS-ADL score. No patients required reoperation for graft-related issues. Lesion fill exceeding 67% by MRI assessment was noted in 69.2% of lesions; depth of lesion fill did not correlate with clinical outcomes. Quantitative T2-mapping revealed prolonged relaxation time at the graft site compared with adjacent normal cartilage at both deep and superficial zones.

CONCLUSIONS

This study found significantly improved pain and function in patients treated with PJAC for symptomatic patellofemoral articular cartilage defects. No patients required reoperation for graft-related issues. Postoperative MRI revealed majority lesion fill in more than 69% of patients, but persistent morphologic differences between graft site and normal adjacent cartilage remain. Though we support PJAC use in this setting to improve patient subjective outcomes, improved appearance on postoperative imaging was not found to provide additional clinical benefit.

LEVEL OF EVIDENCE

Level IV, case series.

Articular cartilage paste graft for severe osteochondral lesions of the knee: a 10- to 23-year follow-up study

PURPOSE

The purpose of this study is to evaluate the clinical outcomes of the articular cartilage paste graft procedure at a minimum of 10 years from surgery. It is hypothesized that articular cartilage paste grafting can provide patients with a durable repair of severe full-thickness osteochondral injuries, measured by persistence of procedure-induced benefit and subjective outcome scores at 10 or more years.

METHODS

Seventy-four patients undergoing paste grafting at a mean age of 45.3 ± 10.8 years (range 13-69 years) were followed up at a mean of 16.8 ± 2.4 years (range 10.6-23.2 years) post-operatively using validated subjective outcome measures; Kaplan-Meier survival analysis was performed to estimate expected population benefit time.

RESULTS

Kaplan-Meier estimated median benefit time of 19.1 years (mean: 16.6 ± 0.9 years) for all patients undergoing paste grafting. Thirty-one (41.9 %) patients had progressed to arthroplasty at a mean of 9.8 ± 5.6 years (range 0.4-20.6 years). Ninety percent of patients reported that the procedure provided good to excellent pain relief. Median IKDC subjective score increased significantly at most recent follow-up (70.1) compared to preoperative (55.7, p = 0.013). Median WOMAC scores decreased significantly from 26 to 14 (p = 0.001). Median Tegner score increase from 4 to 6 was not found to be significant (ns). VAS pain averaged 23/100 at most recent follow-up.

CONCLUSIONS

Patients who underwent the paste grafting reported improved pain, function, and activity levels for an expected mean of 16.6 years, and for those who ultimately progressed to knee replacement, surgical treatment including the paste graft was able to delay arthroplasty until a mean age of 60.2 years, an age at which the procedure is commonly performed. Full-thickness articular cartilage loss can be successfully treated, reducing pain, and improving function, using this single-step, inexpensive arthroscopic procedure.

LEVEL OF EVIDENCE

IV.

Functional outcomes after patellar autologous osteochondral transplantation

PURPOSE

The aim of the present study was to assess clinical evaluation of patients who underwent autologous osteochondral transplantation of the patella.

METHODS

This prospective study assessed outcomes of 20 patients who underwent patellar autologous osteochondral transplantation at four time-points: preoperatively, 3 days, 6 months, and 2 years after surgery. The following outcomes were assessed at each time-point: pain (VAS), gait, swelling, trophic status, muscle strength, patellar mobility, and range of motion. The Tegner scale was also applied for each time-point.

RESULTS

All parameters improved, except for patellar mobility, which did not show any change. Pain score decreased from 7.1 (SD 2.3) to 2.4 (SD 2.6) at the 2-year assessment; limping decreased from 70 % before surgery to 15 % 2 years later; swelling scores decreased from an average of 1.8 (SD 0.8) 3 days after surgery to 0.5 (SD 0.7) at the 2-year assessment; muscle strength increased from 3.9 (SD 0.8) to 4.7 (SD 0.7) points at final follow-up; and the range of motion increased from 84 (SD 16.2) to 132 (SD 10.7) degrees 2 years later. Tegner score before surgery ranged from 0 to 5, and after 2 years, it ranged from 5 to 9.

CONCLUSION

Autologous osteochondral transplantation for the treatment of patellar chondral lesion was associated with significant improvement in pain, gait, swelling, and range of motion 2 years after surgery, achieving scores similar to uninjured knees. Most of them were able to return to sports activity after 6 months (recreational level) and 2 years (competitive level).

LEVEL OF EVIDENCE

IV.

Cartilage Regeneration in Full-Thickness Patellar Chondral Defects Treated with Particulated Juvenile Articular Allograft Cartilage: An MRI Analysis

Background Full-thickness cartilage lesions of the patella represent a common source of pain and dysfunction. Previously reported surgical treatment options include marrow stimulation, cell-based treatments, and osteochondral transfer. Minced juvenile allograft cartilage is a novel treatment option that allows for a single stage approach for these lesions. Hypothesis Particulated juvenile allograft cartilage (PJAC) for the treatment of chondral defects of the patella would offer acceptable lesion fill rates, mature over time, and not be associated with any negative biologic effects on the surrounding tissue. Methods A retrospective chart review of prospectively collected data was conducted to identify consecutive patients who were treated with PJAC for a full thickness symptomatic cartilage lesion. Qualitative (fast spin echo) and quantitative (T2 mapping) magnetic resonance imaging (MRI) was undertaken at the 6-, 12-, and 24-month postoperative mark. Numerous patient, lesion, and graft specific factors were assessed against MRI scores and percent defect fill of the graft. Graft maturation over time was also assessed. Results Forty-five patients total were included in the study. Average age at the time of surgery was 26.5 years (range 13-45 years), average lesion size was 208 mm² (range 4-500 mm²), and average donor age was 49.5 months (range 3-120 months). Sixty percent of the patients were female, while 93% of all patients underwent a concomitant procedure at the time of the index operation. Six-month MRI findings revealed that no patient-, graft-, or donor-specific factors correlated with MR scores, and 82% of the knees demonstrated good to excellent fill. Twelve-month MRI findings revealed that T2 relaxation times of deep graft demonstrated negative correlation with patient age ( P = 0.049) and donor age ( P = 0.006), the integration zone showed a negative correlation with donor age ( P = 0.026). In all, 85% of patients at 12 months displayed good to moderate fill of the graft. At 24 months, patient age demonstrated negative correlation with average T2 relaxation times of the deep and superficial graft ( P = 0.005; P = 0.0029) and positive correlation with the superficial zone of the adjacent cartilage ( P = 0.001). Donor age showed negative correlation with grayscale score ( P = 0.004) and T2 relaxation times at deep integration zone ( P = 0.018). T2 relaxation times of deep and superficial graft and integration zone improved over time ( P < 0.001) and between each time point. Conclusions Particulated juvenile allograft tissue appears to be an acceptable reconstructive option for full-thickness cartilage lesions of the patella, offering satisfactory tissue defect fill at 6, 12, and 24 months after surgery. Imaging of the repaired cartilage demonstrates progressive graft maturation over time.

Two-Year Evaluation of Osteochondral Repair with a Novel Biphasic Graft Saturated in Bone Marrow in an Equine Model

Objective To evaluate a biphasic cartilage repair device (CRD) for feasibility of arthroscopic implantation, safety, biocompatibility, and efficacy for long-term repair of large osteochondral defects. Methods The CRD was press-fit into defects (10 mm diameter, 10 mm deep) created in the femoral trochlea of 12 horses. In the contralateral limb, 10 mm diameter full-thickness chondral defects were treated with microfracture (MFX). Radiographs were obtained pre- and postoperatively, and at 4, 12, and 24 months. Repeat arthroscopy was performed at 4 and 12 months. Gross assessment, histology, mechanical testing, and magnetic resonance imaging (MRI) were performed at 24 months. Results The CRD was easily placed arthroscopically. There was no evidence of joint infection, inflammation, or degeneration. CRD-treated defects had significantly more sclerosis compared to MFX early ( P = 0.0006), but was not different at 24 months. CRD had better arthroscopic scores at 4 months compared to MFX ( P = 0.0069). At 24 months, there was no difference in repair tissue on histology or mechanical testing. Based on MRI, CRD repair tissue had less proteoglycan (deep P = 0.027, superficial P = 0.015) and less organized collagen (deep P = 0.028) compared to MFX. Cartilage surrounding MFX defects had more fissures compared to CRD. Conclusion The repair tissue formed after CRD treatment of a large osteochondral lesion is fibrocartilage similar to that formed in simple chondral defects treated with MFX. The CRD can be easily placed arthroscopically, is safe, and biocompatible for 24 months. The CRD results in improved early arthroscopic repair scores and may limit fissure formation in adjacent cartilage.

Outcomes of Patellofemoral Osteochondral Lesions Treated With Structural Grafts in Patients Older Than 40 Years

Background Chondral lesions in the patellofemoral compartment represent a difficult entity to treat among active patients, with no clear consensus on the optimal treatment strategy. The purpose of this study was to review the functional outcomes of patients >40 years old with primary patellofemoral osteochondral lesions who underwent a cartilage restoration procedure with a structural graft. Methods Following institutional review board approval, 35 patients >40 years treated for patellofemoral chondral or osteochondral injuries were retrospectively identified. Seventeen (47%) had prior surgery (mean 1.4 procedures, range 1-4). Average follow-up was 3.6 ± 1.6 years. Average patient age was 51.5 years (range 40-72 years); 54% were male. Twenty-six (74%) had isolated trochlear lesions, 7 had isolated patellar lesions (20%), while 2 (6%) had bipolar lesions. Twenty patients (57%) were treated with synthetic biphasic scaffold plugs (SS), 9 (26%) with fresh osteochondral allograft (OCA) and 6 (17%) with osteochondral autograft transfer (OAT). Outcomes were measured with validated measures: Activity of Daily Living Score (ADL), International Knee Documentation Committee (IKDC) Subjective Evaluation form, and Marx Activity Scale (MAS). Results The average lesion size for the entire cohort was 3.1 ± 1.7 cm². Average defect size was 2.6 ± 1.7 cm² for the SS group, 4.3±1.5 cm² for the OCA group, and 2.9 ± 0.8 cm² for the OAT group ( P > 0.051). Outcome scores for the entire population demonstrated significant improvement in ADL ( P = 0.002) and IKDC scores ( P = 0.004) between baseline and final follow-up, while MAS scores were maintained ( P = 0.51). Conclusion Structural grafts are a viable treatment option for symptomatic focal osteochondral lesions of the patellofemoral joint in patients 40 years and older, with anticipated improvements in pain and function and maintenance of preoperative activity levels.

Cartilage Restoration Techniques for the Patellofemoral Joint

Symptomatic osteochondral lesions of the patellofemoral joint are clinically challenging to manage because of the limited healing potential of articular cartilage; the complex morphology of the patellofemoral joint; the heterogeneity of the articular surface between patients; and high stresses across the joint, which can be altered by malalignment, tilt, or maltracking. Indications for surgery include traumatic lesions, osteochondritis dissecans, and high-grade chondromalacia in association with persistent pain despite a course of nonsurgical management. Various techniques have been described for managing symptomatic osteochondral lesions of the patellofemoral joint, including microfracture, osteochondral autograft transplantation, and biologic cell transplantation, including autologous chondrocyte implantation. Salvage techniques (eg, fresh allograft) may provide satisfactory outcomes after a failed attempt at surgical management. Irrespective of the surgical technique used, outcomes are generally worse in the patellofemoral compartment than in the tibiofemoral joint. The concomitant management of associated pathology, including patellar malalignment, is recommended because it has been shown to improve the success of cartilage restoration procedures.

Autologous Chondrocyte Implantation to Isolated Patella Cartilage Defects

Background Autologous chondrocyte implantation (ACI) is a durable treatment for patients with chondral defects. This study presents the comprehensive evaluation of patients with patella defects treated with ACI at medium- to long-term follow-up. Methods Thirty consecutive patients with isolated chondral lesions of the patella were enrolled prospectively. Primary outcome measures were validated patient reported outcome measures and objective magnetic resonance imaging. Results Nineteen of 30 patients underwent tibial tubercle osteotomy (TTO) to correct lateral maltracking in combination with soft tissue balancing. The defect sizes were large, averaging 4.7 ± 2.1 cm² (range 2.2-30.0 cm²). Pidoriano/Fulkerson classification revealed that 3 defects were type II (lateral), 9 were type III (medial), and 18 were type IV (central/panpatella). Age at the time of surgery was 32 ± 10 years. At follow-up of 2 to 14 years, knee function was rated good to excellent in 25 (83%) patients, fair in 4 (13%) patients, and poor in 1 (3%) patient. Three patients failed treatment after a mean of 75 months (6.25 years). All 3 failures were Workers Compensation (WC) cases. They were older than the non-WC patients, 42 ± 6 years compared with the non-WC 28 ± 9 years ( P = 0.0019). Significant increases in all clinical and health utility outcome scores were seen. Magnetic resonance imaging demonstrated that the fill grade, surface and integrity of the repair tissue correlated with clinical scores. Conclusion ACI to isolated patella defects results in significant functional improvement at a minimum of 24 months, with the results remaining durable at latest follow-up of 15 years. Level of evidence Level 4.

Retropatellar Accessory Portals for Improved Access to the Patella: Anatomic Description and Evaluation of Safety

Background:

Standard knee arthroscopy portals are frequently used to address retropatellar chondral pathology. Alternative portals may offer a safe and simple substitute, particularly when reaching the base of deep lesions is required.

Purpose:

To describe and assess the safety of accessory retropatellar portals.

Study Design:

Descriptive laboratory study.

Methods:

An anatomic study was performed on 10 fresh-frozen cadaveric knees. Medial and lateral retropatellar portals were created, and the distance to adjacent neurovascular structures (common peroneal nerve [CPN] and infrapatellar branch of the saphenous nerve [IPBSN]) and bony landmarks (medial and lateral epicondyles and margins of the midpatella) was recorded. A clinical account of portal use is provided through a retrospective chart review.

Results:

The medial and lateral retropatellar portals were a mean 15.8 ± 15.5 mm and 53.8 ± 7.2 mm from the IPBSN and CPN, respectively. No nerves were contacted in any specimens. Clinically, the portals have been used in 109 cases over a 7-year period without complication.

Conclusion:

The high level of IPBSN variability poses some risk to medial portal use; however, there is little to no risk laterally. Clinical experience with portals suggests that they can be used safely. We recommend careful blunt dissection to minimize chance of iatrogenic nerve injury.

Clinical Relevance:

Retropatellar portals may offer improved access to chondral lesions of the patella, thereby safely allowing one to maintain an arthroscopic approach.

Combined Particulated Juvenile Cartilage Allograft Transplantation and Medial Patellofemoral Ligament Reconstruction for Symptomatic Chondral Defects in the Setting of Recurrent Patellar Instability

Successful management of patellar osteochondral lesions has proved difficult, with unreliable outcomes reported using traditional cartilage repair and restoration procedures. Unique considerations for this type of defect include the multiplanar contours of the articular surface of the patella, high compressive and shear forces with knee range of motion that may disrupt graft healing, and the potential need for concomitant surgery to address patellar malalignment and instability. We describe our preferred method for treatment of a symptomatic chondral defect in the setting of recurrent patellar instability using particulated juvenile articular cartilage allograft transplantation and medial patellofemoral ligament reconstruction with semitendinosus allograft. Distinct advantages of this cartilage restoration technique include single-stage restoration of relevant cartilage pathology and the ability to easily contour the graft to the size and shape of the chondral defect.

Fresh osteochondral allograft transplantation for isolated patellar cartilage injury

BACKGROUND

The treatment of patellofemoral cartilage injuries can be challenging. Osteochondral allograft (OCA) transplantation has been used as a treatment option for a range of cartilage disorders.

PURPOSE

To evaluate functional outcomes and survivorship of the grafts among patients who underwent OCA for patellar cartilage injuries.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

An institutional review board-approved OCA database was used to identify 27 patients (28 knees) who underwent isolated OCA transplantation of the patella between 1983 and 2010. All patients had a minimum 2-year follow-up. The mean age of the patients was 33.7 years (range, 14-64 years); 54% were female. Twenty-six (92.9%) knees had previous surgery (mean, 3.2 procedures; range, 1-10 procedures). The mean allograft area was 10.1 cm(2) (range, 4.0-18.0 cm(2)). Patients returned for clinical evaluation or were contacted via telephone for follow-up. The number and type of reoperations were assessed. Any reoperation resulting in removal of the allograft was considered a failure of the OCA transplantation. Patients were evaluated pre- and postoperatively using the modified Merle d'Aubigné-Postel (18-point) scale, the International Knee Documentation Committee (IKDC) pain, function, and total scores, and the Knee Society function (KS-F) score. Patient satisfaction was assessed at latest follow-up.

RESULTS

Seventeen of the 28 knees (60.7%) had further surgery after the OCA transplantation; 8 of the 28 knees (28.6%) were considered OCA failures (4 conversions to total knee arthroplasty, 2 conversions to patellofemoral knee arthroplasty, 1 revision OCA, 1 patellectomy). Patellar allografting survivorship was 78.1% at 5 and 10 years and 55.8% at 15 years. Among the 20 knees (71.4%) with grafts in situ, the mean follow-up duration was 9.7 years (range, 1.8-30.1 years). Pain and function improved from the preoperative visit to latest follow-up, and 89% of patients were extremely satisfied or satisfied with the results of the OCA transplantation.

CONCLUSION

OCA transplantation was successful as a salvage treatment procedure for cartilage injuries of the patella.

Autologous Osteochondral Transplantation to Treat Patellar Chondral Injuries

Introduction

Autologous osteochondral transplantation for the treatment of patellar chondral injuries is a single-stage procedure through a single surgical approach that allows replacement of the chondral injury with an osteochondral plug that has the same cartilaginous hyaline characteristics as the site had before the injury.

Step 1 Preoperative Planning

Make radiographs (anteroposterior, lateral, and Merchant patellofemoral views), computed tomography scans, and magnetic resonance imaging (MRI) of the knee for an anatomic study and to determine cartilage lesion details.

Step 2 Perform Knee Arthroscopy and Lesion Identification

Classify and locate the cartilage lesion on the basis of the intraoperative arthroscopic knee evaluation.

Step 3 Use a Parapatellar Approach

Perform a parapatellar incision and patellar eversion as they are necessary to access cartilage lesions.

Step 4 Harvest the Osteochondral Plug at the Donation Site

Harvest an appropriate osteochondral graft, which is essential for a successful procedure. Perpendicular graft harvesting is crucial for a perfect cartilage surface match.

Step 5 Characterize and Prepare the Lesion

At this point, prepare the receptor area with a power drill.

Step 6 Insert the Osteochondral Plug into the Receptor Site

Insert the graft with press-fit fixation.

Step 7 Postoperative Care

Instruct all patients to follow a rehabilitation protocol.

Results

Our clinical experience with this procedure has corresponded to the scores and MRI-based findings in our original study, in which we prospectively evaluated thirty-three knees in patients who underwent autologous osteochondral transplantation for a symptomatic full-thickness cartilaginous injury on the patellar articular surface.IndicationsContraindicationsPitfalls & Challenges.

Autologous osteochondral transplantation for treating patellar chondral injuries: evaluation, treatment, and outcomes of a two-year follow-up study

BACKGROUND

The patella is the largest human sesamoid bone and often sustains chondral injury. There is no consensus on how to treat a full-thickness, symptomatic articular cartilage injury of the patella. We analyzed the clinical and functional outcomes of patients with symptomatic full-thickness patellar chondral lesions treated with autologous osteochondral transplantation and evaluated osteochondral autograft bone-plug integration through magnetic resonance imaging.

METHODS

In this prospective study, thirty-three patients with a symptomatic full-thickness patellar chondral injury surgically treated with autologous osteochondral transplantation were evaluated before and after surgical treatment with a minimum two-year follow-up using the Lysholm, Kujala, and Fulkerson questionnaires and the Short Form-36 health survey score. Magnetic resonance images were made at six and twelve months postoperatively and studies were performed to analyze the osteochondral autograft bone-plug integration.

RESULTS

All thirty-three patients showed a significant improvement in functional scores two years after surgery. The average Lysholm scores were 57.27 points preoperatively and 80.76 points at two years postoperatively, the average Kujala scores were 54.76 points preoperatively and 75.18 points at two years postoperatively, and the Fulkerson average scores were 54.24 points preoperatively and 80.42 points at two years postoperatively. The Short Form-36 life quality score improved significantly. Two years after surgery, all magnetic resonance images showed full bone-plug integration into the patella.

CONCLUSIONS

Autologous osteochondral transplantation is a successful technique to surgically treat symptomatic full-thickness patellar articular cartilage injuries smaller than 2.5 cm in diameter. Patients had a significant improvement in clinical scores. Bone-plug integration and surface alignment were demonstrated in all patients two years after surgery.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Temporal in vivo assessment of fresh osteochondral allograft transplants to the distal aspect of the femur by dGEMRIC (delayed gadolinium-enhanced MRI of cartilage) and zonal T2 mapping MRI

BACKGROUND

Zonal T2 mapping and dGEMRIC (delayed gadolinium-enhanced magnetic resonance imaging of cartilage) are diagnostic quantitative techniques to evaluate the biochemical health of articular cartilage. We adapted these techniques to investigate the results of osteochondral allograft transplantation and correlated the findings with patient-reported outcomes.

METHODS

Nine patients with contained ICRS (International Cartilage Repair Society) grade-4 defects of the articular portion of a femoral condyle were treated with fresh osteochondral allografts and were evaluated prospectively with dGEMRIC and T2 mapping before and after gadolinium administration. The KOOS (Knee Injury Osteoarthritis Outcome Score) and IKDC (International Knee Documentation Committee) subjective scores were obtained at baseline and at one and two years postoperatively. For quantitative T2 mapping, regions of interest were drawn in the deep and superficial layers of allograft and control cartilage. For dGEMRIC analyses, the relaxation rate, post-gadolinium change in relaxation rate, and ratio between changes in the allograft and control regions of interest were calculated from T1 values.

RESULTS

The mean ratio between the post-gadolinium changes in the allograft and control cartilage was 1.13 at one year and 1.55 at two years, and the ratio increased in eight of nine patients from one to two years. There was no difference between the mean T2 values in the deep zone of the allograft and control cartilage at one or two years (p > 0.05), but mean T2 values were higher in the superficial zone of the allograft cartilage at one (p < 0.0001) and two (p < 0.028) years. The mean improvement from baseline was significant at one and two years for the IKDC and all five KOOS subdomains (p < 0.05). All or nearly all patients showed improvements in all clinical outcomes scores at one year.

CONCLUSIONS

Functional MRI techniques can be applied to noninvasively assess the biochemical health of cartilage after osteochondral allograft transplantation. The MRI findings correlated with certain patient-reported outcomes in the early postoperative period. Relative glycosaminoglycan content and the collagen structure of allograft cartilage may undergo time-dependent degeneration. A patient's perception of clinical outcome and quality of life is likely multifactorial and is impacted by more than the health of the allograft cartilage.

Biphasic scaffolds for repair of deep osteochondral defects in a sheep model

BACKGROUND

To oppose the disadvantages of autologous osteochondral transplantation in the treatment of deep osteochondral defects such as donor site morbidity, size limitation, and insufficient chondral integration, we developed two biphasic scaffolds of either hydroxylapatite/collagen (scaffold A) or allogenous sterilized bone/collagen (scaffold B) and tested their integration in a sheep model.

METHODS

We collected chondral biopsies from 12 sheep for the isolation of chondroblasts and cultured them for 4 wk. We created defects at the femoral condyle and implanted either scaffold A or B with chondrocytes or cell free. After 6 wk, animals were euthanized, we explanted the condyles, and evaluated them using histological, immunohistochemical, molecular biological, and histomorphometrical methods.

RESULTS

Specimens with scaffold A showed severe lowering of the surface, and the defect size was larger than for scaffold B. We found more immune-competent cells around scaffold A. Chondrocytes were scarcely detected on the surface of both scaffolds. Histomorphometry of the interface between scaffold and recipient showed no significant difference regarding tissue of chondral, osseous, fibrous or implant origin or tartrate-resistant acid phosphatase-positive cells. Real-time reverse transcriptase-polymerase chain reaction analysis revealed significant up-regulation for collagen II and SOX-9 messenger ribonucleic acid expression on the surface of scaffold B compared with scaffold A.

CONCLUSIONS

Scaffold B proved to be stable and sufficiently integrated in the short term compared with scaffold A. More extensive evaluations with scaffold B appear to be expedient.

The effect of tibial tuberosity realignment procedures on the patellofemoral pressure distribution

PURPOSE

The study was performed to characterize the influence of tibial tuberosity realignment on the pressure applied to cartilage on the patella in the intact condition and with lesions on the lateral and medial facets.

METHODS

Ten knees were loaded in vitro through the quadriceps (586 N) and hamstrings (200 N) at 40°, 60°, and 80° of flexion while measuring patellofemoral contact pressures with a pressure sensor. The tibial tuberosity was positioned 5 mm lateral of the normal position to represent lateral malalignment, 5 mm medial of the normal position to represent tuberosity medialization, and 10 mm anterior of the medial position to represent tuberosity anteromedialization. The knees were tested with intact cartilage, with a 12-mm-diameter lesion created within the lateral patellar cartilage, and with the lateral lesion repaired with silicone combined with a medial lesion. A repeated measures ANOVA and post hoc tests were used to identify significant (P < 0.05) differences in the maximum lateral and medial pressure between the tuberosity positions.

RESULTS

Tuberosity medialization and anteromedialization significantly decreased the maximum lateral pressure by approximately 15% at 60° and 80° for intact cartilage and cartilage with a lateral lesion. Tuberosity medialization significantly increased the maximum medial pressure for intact cartilage at 80°, but the maximum medial pressure did not exceed the maximum lateral pressure for any testing condition.

CONCLUSIONS

The results indicate that medializing the tibial tuberosity by 10 mm reduces the pressure applied to lateral patellar cartilage for intact cartilage and cartilage with lateral lesions, but does not overload medial cartilage.

Synthetic resorbable scaffolds for the treatment of isolated patellofemoral cartilage defects in young patients: magnetic resonance imaging and clinical evaluation

BACKGROUND

Surgical management of patellar cartilage defects remains controversial. The ideal technique to regenerate hyaline cartilage is not yet defined. However, a synthetic resorbable osteochondral scaffold plug (TruFit CB) seems to offer a treatment option with good results at short-term follow-up, at least in the condylar setting.

HYPOTHESIS

A synthetic implant provides a simple and efficacious means of treating the cartilage defects of the patellofemoral joint in young patients.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A study was designed to evaluate prospectively short- and medium-term results in patients with osteochondral patellar defects treated with synthetic reabsorbable scaffolds. Patient outcome scores (Short Form 36 [SF-36] and Knee injury and Osteoarthritis Outcome Score [KOOS]), demographics, prior surgeries, and data from a physical examination were collected at baseline (before implantation) and at 6, 12, and 24 months after surgery. Defect characteristics were collected during implantation. Diagnosis and monitoring were performed by magnetic resonance imaging.

RESULTS

Ten patients with a mean age of 33.3 years (range, 16-49 years) were evaluated prospectively at 24 months' follow-up. The number of plugs used for each patient ranged from 1 to 4. At 1-year follow-up, the results were satisfactory in 8 of 10 patients, and poor in 2, according to clinical assessment (KOOS, visual analog scale, and SF-36). At 18 months of follow-up, all patients except one complained of pain and knee swelling. Reoperation rate for implant failure at final follow-up was 70%. Magnetic resonance imaging at final follow-up showed a cylindrical cavity of fibrous tissue instead of subchondral bone restoration.

CONCLUSION

A synthetic implant can improve symptoms and joint function, especially for small lesions, only for a short period of time. However, 2 years of monitoring has shown its failure in restoring the subchondral bone despite the formation of predominant hyaline cartilage from synthetic resorbable scaffolds. Under current conditions and according to our experience, we do not recommend TruFit synthetic implants for osteochondral patellar defects in active patients.

OSTEOCHONDRAL AUTOLOGOUS TRANSPLANTATION FOR TREATING CHONDRAL LESIONS IN THE PATELLA

Objective: The primary aim of this study was to assess the clinical and functional evolution of patients with total-thickness symptomatic cartilaginous injury of the patellar joint surface, treated by means of osteochondral autologous transplantation. Methods: This prospective study was conducted from June 2008 to March 2011 and involved 17 patients. The specific questionnaires of Lysholm, Kujala and Fulkerson were completed preoperatively and one year postoperatively in order to assess the affected knee, and SF-36 was used to assess these patients’ general quality of life. The nonparametric paired Wilcoxon test was used for statistical analysis on the pre and postoperative questionnaires. The data were analyzed using the SPSS for Windows software, version 16.0, and a significance level of 5% was used. Results: The Lysholm preoperative and postoperative average scores were 54.59 and 75.76 points (p < 0.05). The Fulkerson pre and postoperative average scores were 52.53 and 78.41 points (p < 0.05). Conclusions: We believe that autologous osteochondral transplantation is a good treatment method for total-thickness symptomatic chondral lesions of the joint surface of the patella.

Magnetic Resonance Imaging of Cartilage Repair: A Review

Articular cartilage lesions are a common pathology of the knee joint, and many patients may benefit from cartilage repair surgeries that offer the chance to avoid the development of osteoarthritis or delay its progression. Cartilage repair surgery, no matter the technique, requires a noninvasive, standardized, and high-quality longitudinal method to assess the structure of the repair tissue. This goal is best fulfilled by magnetic resonance imaging (MRI). The present article provides an overview of the current state of the art of MRI of cartilage repair. In the first 2 sections, preclinical and clinical MRI of cartilage repair tissue are described with a focus on morphological depiction of cartilage and the use of functional (biochemical) MR methodologies for the visualization of the ultrastructure of cartilage repair. In the third section, a short overview is provided on the regulatory issues of the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) regarding MR follow-up studies of patients after cartilage repair surgeries.

Cartilage defects of the femoral trochlea

Despite improvements in the ability to detect articular cartilage defects of the trochlea, determining the significance of these lesions remains difficult. Physical examination and history taking remain the best way to estimate the clinical impact of these lesions. Debridement and/or microfracture are often initial surgical interventions; these procedures can be expected to provide functional improvement in over 50%, but studies suggest that the amount of improvement deteriorates within 3 years. While initial reports on ACI and osteochondral allografts in the treatment of trochlear defects appear to be more promising solutions, long-term follow-up studies are lacking. Similarly, the effect of tibial tubercle osteotomy combined with cartilage restoration techniques remains unresolved. Nonetheless, based on the limited available evidence, ACI or osteochondral allografts combined with a tibial tubercle osteotomy when appropriate have provided the most durable treatment for these difficult-to-treat lesions.

Improving vastus medialis obliquus function reduces pressure applied to lateral patellofemoral cartilage

The current study was performed to characterize how improving vastus medialis obliquus (VMO) function influences the pressure applied to patellofemoral cartilage. An additional focus was characterizing how lateral and medial cartilage lesions influence cartilage pressures. Ten knees were flexed to 40 degrees, 60 degrees, and 80 degrees in vitro, and forces were applied to represent the VMO and other muscles of the quadriceps group while a thin film sensor measured joint pressures. The knees were loaded with a normal VMO force, with the VMO force decreased by approximately 50%, and with the VMO unloaded. After tests were performed with the cartilage intact, all tests were repeated with a 12-mm-diameter lesion created within the lateral cartilage, with the lateral lesion repaired with silicone, and with a medial lesion created. Based on a two-way repeated measures ANOVA and post-hoc tests, increasing the force applied by the VMO significantly (p < 0.05) decreased the maximum lateral pressure and significantly increased the maximum medial pressure at each flexion angle. A lateral cartilage lesion significantly increased the maximum lateral pressure, while a medial lesion did not significantly influence the maximum medial pressure. Improving VMO function can reduce the pressure applied to lateral cartilage when lateral lesions are present.

Magnetic resonance imaging assessment of chondral lesions and repair

Standardized, validated magnetic resonance imaging sequences that are sensitive for articular cartilage are available for clinical use in magnetic resonance imaging units. Whereas two-dimensional sequences are helpful in the assessment of repair morphology, three-dimensional sequences with isotropic voxels measure cartilage volumes and provide an accurate assessment of fill following repair. Protocols should be modified so that sequences are not limited by instrumentation. The addition of quantitative magnetic resonance imaging techniques provides an objective assessment of repair-tissue biochemistry as well as of the tissue at the peripheral integration with the host hyaline cartilage.

Magnetic resonance imaging of cartilage repair

Magnetic resonance imaging is an important noninvasive modality in characterizing cartilage morphology, biochemistry, and function. It serves as a valuable objective outcome measure in diagnosing pathology at the time of initial injury, guiding surgical planning, and evaluating postsurgical repair. This article reviews the current literature addressing the recent advances in qualitative and quantitative magnetic resonance imaging techniques in the preoperative setting, and in patients who have undergone cartilage repair techniques such as microfracture, autologous cartilage transplantation, or osteochondral transplantation.

[Isolated arthrosis of the patellofemoral joint in younger patients (<50 years)]

In the majority of cases, arthrosis of the patellofemoral joint (PFJ) is combined with arthrosis of the femorotibial compartment and thus assumes a somewhat secondary role. Nevertheless, it can occur as an isolated entity. Several radiological studies evidenced isolated degenerative alterations in the PFJ in the age group >55 years (13.6-24.0% in women and 11.0-15.4% in men). In younger patients the incidence is lower and is mainly associated with patellar instability or post-traumatic arthrosis. Just the same, the choice of appropriate treatment for these patients is challenging. Total replacement can be recommended for older and less active patients. In contrast, for younger and more active patients, various conservative treatment options and more demanding operative techniques are available to the surgeon to avoid arthroplasty. This article describes the different therapeutic possibilities for managing arthrosis of the PFJ in patients aged <50 years.