Purpose

The purpose of this study was to evaluate the outcomes including survival rate and to analyze the factors that affect the survival rate after medial open wedge high tibial osteotomy (MOWHTO) performed as the primary treatment for medial unicompartmental osteoarthritis of the knee at a minimum follow-up

Methods and Materials

Out of 391 knees of MOWHTO performed between October 2003 and December 2009 at our institute, 339 knees with minimum follow-up period of five years were included in this retrospective analytical study. Clinical evaluation using Knee Society Score (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and radiographic evaluation including Hip-Knee-Ankle angle were done preoperatively and postoperatively. Main failure criteria for survival were the conversion to total knee replacement or KSS<60 points. Also, risk factors that affected the survival after MOWHTO were analyzed.

Results

The mean KSS and WOMAC scores were significantly improved after surgery (87.3 and 18.5 at 5 years and 81.7 and 23.6 at 10 years, respectively). The mean HKA angle was corrected from 7.2° varus to 3.4° valgus after 1 year of surgery and remained until 10 years after surgery without significant differences (2.9° valgus at 5 years and 2.3° valgus at 10 years, p>0.05). Using the Kaplan-Meier survivorship estimate of failure, the probability of survival for MOWHTO was 96.8% at 5 years, 87.1% at 10 years, and 85.3% at 13 years. Of all factors analyzed using multivariate regression analysis, age≥65years (HR=2.52, p=0.034), medial compartment cartilage injury ICRS grade≥4 (HR=3.13, p=0.004), lateral compartment cartilage injury ICRS grade≥2 (HR=3.63, p=0.003), postoperative HKA angle<0° (HR=3.01, p=0.003) were associated with the failure.

Conclusion

The MOWHTO provided good survival at mid- to long-term follow-up. The old age, high-grade cartilage injury on medial and lateral compartment, under-correction of postoperative HKA angle appeared to be significant factors associated with the failure after MOWHTO .

Purpose

The purpose of this study was (1) to investigate whether there was good agreement between EOS imaging based and three-dimensional (3D) CT reconstruction based technique in measuring femoral, tibial and femorotibial torsion; (2) to verify the reliability and reproducibility of EOS Imaging in measuring femoral, tibial and femorotibial torsion.

Methods and Materials

A prospective study was conducted including 18 adult volunteers (36 lower extremities) (24±2 years old). Femoral and tibial torsion were measured by both EOS imaging and three-dimensional CT reconstruction. Bland-Altman plots were performed to evaluate the difference between femoral and tibial torsion measurements obtained by these two methods. The intraclass correlation coefficient was used to evaluate intrareader agreement.

Results

The mean difference between the two methods was 3°(range, –9°to 4°) for femoral torsion, 0°(range, –6°to 6°) for tibial torsion and 0°(range, –4° to 5°) for femorotibial torsion. No statistically significant difference between the measurements of the two methods was detected by Bland-Altman plots. With the exception of one measurement of femoral torsion, one measurement of tibial torsion and one measurement of femorotibial torsion, all EOS imaging measurements were within the 95% limits of agreement (the mean ± 1.96 SD). Intrareader agreement was statistically significant (P<0.001) for all measurements, with high intraclass correlation coefficients. For EOS imaging, the intraclass correlation coefficient (ICC) was 0.92 for the femoral measurement, 0.92 for the tibial measurement and 0.918 for the femorotibial measurement; the corresponding values for CT were 0.95, 0.927 and 0.889.

Conclusion

There was good agreement between EOS imaging based and 3D CT reconstruction based technique in measuring femoral, tibial and femorotibial torsion; and good reliability and reproducibility of EOS Imaging in measuring femoral, tibial and femorotibial torsion was also verified.

Purpose

Analysis and quantification of bone healing after open wedge high tibial osteotomy

Methods and Materials

Study Phase 1:High tibial osteotomy was performed on six lower extremities of human body donors and experimental X-rays and CT scans were applied. Different techniques were evaluated by 3 specialists for best representation of the osteotomy gap.

Study Phase 2: Optimized radiological techniques were used for follow-up on 12 patients. The radiographs were examined by 3 specialists measuring 10 different parameters. The CT scans were analyzed with semi-automatic computer software for quantification of bone ossification.

Results

The osteotomy gap was best represented in 30° of flexion in the knee and 20° internal rotation of the leg. There were significant changes of the medial width over time (p < 0.001) as well as of the length of fused osteotomy, the Schröter score, sclerosis, trabecular structure and zone area measurements. Sclerosis, medial width of the osteotomy and area measurements were detected as reproducible parameters. Bone mineral density was calculated using the CT scans, showing a significantly higher value 12 weeks postoperatively (112.5 mg/ccm) than at baseline (54.6 mg/ccm). The ossification of the gap was visualized by color-coding.

Conclusion

Sclerosis and medial width of the osteotomy gap as well as area measurements were determined as reproducible parameters for evaluation of bone healing. Quantification of bone ossification can be calculated with CT scans using a semi-automatic computer program and should be used for research in bone healing.

Purpose

The Agili-C implant has shown to provide early and predictable knee joint regeneration (1). The repair process appears to involve stem cell recruitment and repair of both subchondral bone and articular cartilage (2).

1. Kon, E. et al., A novel aragonite-based scaffold for osteochondral regeneration: early experience on human implants and technical developments. Injury, 2016. 47 Suppl 6: p. S27-S32.

2. Kon, E. et al., Osteochondral regeneration using a novel aragonite-hyaluronate bi-phasic scaffold in a goat model. Knee Surg Sports Traumatol Arthrosc, 2014. 22(6): p. 1452-64.

Methods and Materials

12 Subjects, recruited as part of a 24-month, multi-center Agili-C implant performance study (143 Subject cohort), were evaluated at baseline and at least annually for 48 months. The Subjects filled out KOOS and IKDC questionnaires, as well as performed an annual MRI of the index knee.

Results

Average age was 35±6.3 (9M, 3F). Defect location was on the Medial condyle (7 subjects) and Lateral condyle (5 subjects). Implant diameter was 10mm in 5 cases, 14mm in 3 cases, 17mm in 2 cases and 20mm in one case.

Average overall KOOS score was 38±15 and the KOOS pain subscale was 49±15 at baseline, improving to 83±10 and 74±11 at 12 months, 86±14.6 and 79±15 at 24 months, 88±11.5 and 83±15 at 36 months, 86±17 and 82±18.5 at 48 months.

Conclusion

A medium term (48 month) follow-up of the Agili-C indicates that there is no deterioration of the repaired tissue during this period. Knee function remains close to the general population-average, supporting the histological results obtained in goats, indicating restoration of hyaline cartilage and normal subchondral bone [2]. The repair reaction induced by the Agili-C implant appears to preserve knee joint function and to provide consistent pain relief.

Purpose

Different approaches have been proposed to treat osteochondral defects. Among them, researches are recently focusing on the role of subchondral bone with regard to articular surface disease, with new specifically developed bioengineered strategies. Aim of this study is to evaluate the clinical and MRI outcome after the implantation of a nanostructured biomimetic collagen-hydroxyapatite construct for the treatment of chondral and osteochondral defects of the knee in a large cohort of patients.

Methods and Materials

One hundred twenty patients (85 men, 35 women), affected by grade III-IV femoral condyle or trochlea chondral lesions or osteochondritis dissecans (OCD) were consecutively treated. The mean age was 31.0±11.1 years, the mean lesion size was 3.5±2.3 cm². Seventy patients had undergone previous surgeries, whereas concurrent procedures were necessary in sixty-one cases. The clinical outcome was evaluated using the IKDC and Tegner scores at 12 and 36 months of follow-up. At follow-up times a MRI was performed and evaluated with the MOCART score.

Results

All the scores improved significantly: IKDC score increased from the baseline to 12 months of follow-up (46.0±16.6 to 70.9±16.9, p<0.005), with a slight further increase up to 36 months’ follow-up (74.1±21.2, n.s.). Tegner score increased significantly but the pre-injury activity level wasn’t recovered. Six patients (5%) failed the treatment and were re-operated for the same reason. Patients affected by OCD had better clinical improvement than those with degenerative lesions. Some abnormal MRI findings were present, even though no correlation was found with the clinical outcome.

Conclusion

This one-step biomimetic approach developed to favor osteochondral tissue regeneration is effective in treating knees affected by damages of the articular surface, leading to a significant clinical improvement. However, abnormal MRI findings were present, even if not correlated with the clinical outcome.

Purpose

Matching donor and recipient site curvature is a known challenge when performing osteochondral autograft transfers (OAT) for articular lesions of the distal femur. Using radius of curvature (ROC), our purpose is to determine ideal donor sites for various recipient sites. We hypothesize that certain donor regions will have a ROC different than certain recipient regions.

Methods and Materials

Nineteen cadaveric femurs were scanned with a high-resolution sensor. Multiple points within four recipient and four donor regions were analyzed. Grafts with six, eight, and ten-millimeter diameter were simulated and average ROC for each region was calculated. Recipient regions analyzed were the distal medial (DMFC) and lateral femoral condyles (DLFC) as well as the posterior medial (PMFC) and lateral femoral condyles (PLFC). Donor regions were the lateral (LTR) and medial trochlear ridges (MTR) as well as the lateral (LICN) and medial intercondylar notch (MICN). Figure 1 shows example of a 3D scan.

Results

Analyzing 6mm grafts, we found no significant difference in ROC of the LICN and all recipient sites(p=.061,.062,.310,.475). The same was true for the LTR donor site(p=.980,.254,.257,.783). A significant difference was found between the MTR and both the DMFC and DLFC(p=.009,.009). No significant difference was found between the MTR and the PMFC and PLFC(p=.078,.144). The MICN had a significantly different ROC than each recipient site(p<.001). For 8mm grafts, only the MICN had a significantly different ROC compared to recipient sites(p<.05). Analyzing 10mm grafts, there were no significantly different comparisons of donor and recipient site ROC(p>.05). Figure 2 displays our primary findings.

Conclusion

When using 6mm OAT plugs, our study demonstrates that the LICN and LTR are excellent harvest options for all recipient sites on the femoral condyles with respect to ROC. For 8 mm plugs, the LICN, LTR, and MTR were acceptable donor sites. For 10 mm plugs, all 4 donor sites were acceptable.

Purpose

The treatment of the steroid induced osteonecrosis of the knee is still challenging. The purpose of this study was to investigate the long-term survivorship and outcomes of the autologous osteochondral transplantation (AOT) for the steroid induced osteonecrosis of the knee.

Methods and Materials

Patients who underwent AOT due to the steroid induced osteonecrosis of the knee between 1998 and 2007 were included. The survivorship was evaluated with Kaplan-Meier method with the revision surgery on the transplanted cartilage as an end-point, and clinical outcomes were evaluated with the International Knee Documentation Committee (IKDC) subjective score and radiographical changes.

Results

Fourteen knees (medial femoral condyle in 5 cases, lateral in 9 cases) of 10 patients (2 males and 8 females) were enrolled. The mean age at the surgery was 32.5 ± 11.0 years-old. All patients were followed-up more than 10 years (14.2 ± 2.8 years, 10.4 -20.0 years). The primary diseases were systemic lupus erythematosus in 5 knees of 3 patients, idiopathic thrombocytopenic purpura in 3 knees of 2 patients, nephrosis syndrome in 3 knees of 2 patients, leukemia in 1 knee, IgA nephropathy in 1 knee, and andrelapsing polychondritis in 1 knee. The lesion size of 6.9 ± 2.8 cm² was repaired using 3.9 ± 0.8 osteochondral plugs. Although there was no revision surgery for the failed cartilage repair and survival rate was 100 % at final follow-up, one case underwent arthroscopic removal of a loose body at 96 months. IKDC subjective score improved from 32.9 ± 13.4 to 74.3 ± 21.3 (p value < 0.001) at final follow-up. Although KL grade of femorotibial joint did not changed, the KL grade of patellofemoral joint deteriorated.

Conclusion

AOT is an effective surgery for the steroid induced osteonecrosis of the knee to avoid prosthetic joint replacement in young patients.

Purpose

To investigate the long-term clinical outcomes of cartilage repair in the knee using a hyaluronic acid-based scaffold seeded with bone marrow aspirate concentrate (HA-BMAC) for the treatment of full-thickness cartilage injury.

Methods and Materials

Patients treated for full-thickness chondral defects in the knee with HA-BMAC were prospectively followed for a mean duration of 10 years (range 6-12 years). Clinical outcomes were examined using patient reported scoring instruments that consisted of the Tegner Activity Scale, the International Knee Documentation Committee (IKDC) Subjective score, the visual analogue scale (VAS), and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Comparative analysis of preoperative and postoperative scores was performed and the effects of patient age, BMI, lesion size, number of treated lesions, and concurrent treatment with associated procedures were examined.

Results

Twenty-seven patients (mean age 48 years) were prospectively evaluated for a mean duration of 10 years (range 6-12 years). All scores were significantly increased at final follow-up (p<0.001). No difference in mean outcome scores were identified after categorization of patients by age, lesion size, treatment of multiple lesions, treatment of multiple knee compartments, and treatment of associated procedures. Rank correlation analysis demonstrated a negative correlation of patient age and final outcome scores of IKDC, Tegner, VAS, and KOOS subsets of Pain, ADL, Sports, and QOL. No association of BMI or lesion size and outcome scores was identified.

Conclusion

Repair of full-thickness cartilage injury in the knee using a hyaluronic acid-based scaffold with activated bone marrow aspirate concentrate provides good to excellent clinical outcomes in large lesions at long-term follow-up. Good clinical outcomes can be expected in patients over 45 years of age, but outcomes may be comparatively more successful in younger patients.

Purpose

Precise preparation of cartilage defects is technically critical in joint preservation surgery. Whether employing microfracture or advanced methodologies such as matrix induced autologous chondrocyte implantation (MACI), controlled-depth debridement is key to clinical success, with penetration beyond the calcified layer leading to risk of subchondral fracture whereas inadequate debridement leaves behind a sub-optimal base with residual pathologic tissue. To date, techniques to assist level of debridement remain informal, with surgeons employing experience and often attempting to describe audio feedback with distinct sound and pitch changes assisting with debridement when training others. The purpose of this study was to characterize the audiometric properties of chondral defect debridement by cartilage surgery specialists to inform technique and depth of curettage.

Methods and Materials

Audiometric recordings of cartilage defect preparation with a ringed curette at the time of surgical arthrotomy were obtained for formal analysis, to be correlated to the time at which the calcified layer had been satisfactorily debrided according to the operating surgeon. Digital audio analysis was employed to determine peak sound intensity (decibels, dB) of individual curette strokes as well as stroke spectrography to analyze frequency profile from 0 to 22,000 hertz (Hz). Analysis was performed comparing the curette strokes prior to and immediately following satisfactory cartilage debridement by the surgeon in order to characterize tone and volume intensity profile changes.

Results

Peak curette stroke volume intensity was on average 6.0±1.4 dB or 4-fold higher immediately prior to debridement completion as compared to after satisfactory preparation (p<0.01). In addition, stroke pitch changed substantially, with a sharp drop off in frequencies above 2400 Hz observed following satisfactory defect debridement (p<0.01).

Conclusion

Cartilage surgeons can be assisted by both a substantial decrease in heard curette volume intensity and lower curette pitch when achieving satisfactory calcified layer debridement. This may serve as an additional technical aid during cartilage restoration procedures.