Localized cartilage injuries in the ankle occur when distinct areas of the cartilage in
the ankle joint become damaged or worn down. This can lead to pain, swelling, reduced
mobility and function, and an increased risk of osteoarthritis over time. The challenge
with these injuries is that cartilage has a limited capacity for self-healing due to its
lack of direct blood supply. Treatment options remain limited, as conventional methods
such as physiotherapy or anti-inflammatory medications only address symptoms rather than
the underlying damage. More invasive procedures, such as joint replacement or extensive
reconstructive surgery, are associated with prolonged rehabilitation periods and variable
success rates, particularly in younger, active patients. This highlights the need for
precise, customized treatment solutions that can directly repair the damage and
effectively restore joint function. A patient-specific implant has been designed to
address focal cartilage injuries in joints, primarily in the knee but also in the ankle.
The implant is based on advanced imaging and 3D modeling to adapt to the patient's unique
joint anatomy and extent of injury. The method involves open surgery to replace the
damaged cartilage and adjacent bone with a metal implant (cobalt-chromium) that mimics
the patient's original joint surface. This facilitates targeted pain relief and improved
joint function, offering a personalized treatment alternative for patients with localized
cartilage defects. Compared to traditional ankle joint replacements or arthrodesis, the
use of this implant is considered less invasive and associated with a shorter recovery
period, reducing patient burden and allowing for a quicker return to daily activities.
Additionally, the patient-specific design of the implant has the potential to minimize
implant-related complications, such as implant wear and implant-related pain. Early
clinical studies on this implant have shown promising results regarding pain relief,
improved joint function, and patient satisfaction. However, only a limited number of
reports exist to date, and further studies are needed to assess the long-term effects of
the implant on pain, function, and quality of life.
The implant may represent a significant advancement in orthopedic surgery and has the
potential to improve the quality of life for patients suffering from ankle joint injuries
and osteochondral lesions.
In conjunction with the introduction of this method and implant, particularly in younger
patients, the investigators aim to conduct a pilot study on the early outcomes of the
first ten patients, focusing on safety, feasibility, and efficacy.
This project aims to evaluate the surgical outcomes in patients aged 20 to 60 years with
challenging cartilage injuries in the ankle, two years postoperatively following
implantation of a custom-made talus implant. The study focuses on safety, feasibility,
and efficacy. Complications and adverse events will be recorded.
Clinical function will be assessed using the American Orthopaedic Foot and Ankle Society
(AOFAS) hindfoot score, a well-validated and reliable scoring system, while HRQoL will be
assessed using the EQ-5D-5L score.
Ten patients with osteochondral lesions will be included in the study. Patients will be
selected from a clinical population with moderate to severe symptoms and will be treated
at an orthopedic clinic (DS) with expertise in managing ankle osteoarthritis/cartilage
injuries and performing the talus implant implantation. Through this recruitment process,
the investigators aim to establish a cohort that reasonably reflects the patient
population with ankle osteoarthritis at our clinic, thereby enhancing the quality and
relevance of the research.
Upon inclusion, patients will undergo a clinical examination, X-ray, and MRI imaging of
the foot to assess the extent of the injury and joint geometry. The Berndt-Harty
classification system will be used to categorize the injury based on radiographic images,
and the Bristol-Hepple classification will be employed to describe lesion size, edema,
displacement, and cyst formation based on MRI images. Patients will undergo implantation
of the talus implant performed by a qualified orthopedic surgical team. Pre- and
postoperative pain management protocols will be implemented. Standard postoperative
follow-up plans, including rehabilitation and physiotherapy, will be provided. Patients
will be followed up clinically at 6 weeks, 6 months, 1 year, and 2 years postoperatively.
Additional data collected include: Demographic data: Age, sex, surgical time (minutes).
Clinical data: Time of diagnosis, treatment initiation, treatment type, and treatment
course.
Patients will be informed about the study and will provide written consent before
inclusion. To ensure ethical and legal informed consent, patients will receive a detailed
consent form explaining the nature of the study, what participation entails, and how
patient data will be managed to protect confidentiality. Only after obtaining written
consent will patients be included in the study.
In this study, the power calculation is challenged by a limited patient sample, which
affects the potential for statistical significance. With a single cohort of 10 patients
over a two-year period, the sample size restricts the ability to detect statistically
significant differences in AOFAS and EQ-5D-5L scores. Reduced statistical power is an
inherent consequence of the small sample size. The results, primarily descriptive and
exploratory, must be interpreted with caution and regarded as a foundation for further
research. Alternative analytical approaches will be considered to maximize the value of
the collected data.
The following data processing and statistical analysis methods are planned:
Descriptive statistics to summarize demographic and baseline clinical
characteristics of participants.
T-tests or Wilcoxon signed-rank tests to compare pre- and postoperative outcomes on
continuous variables such as pain (NRS), AOFAS scores, and HRQoL (EQ-5D-5L),
depending on data distribution.
ANOVA or Kruskal-Wallis tests for comparisons across multiple time points or groups.
Linear regression models to analyze relationships between predictors (e.g., age,
sex, injury severity) and outcome variables (e.g., pain, function, HRQoL).
Calculation of the Minimum Clinically Important Difference (MCID) for EQ-5D-5L to
establish the smallest score change perceived as clinically meaningful by patients.
Kaplan-Meier survival analysis to estimate revision rates over time.
Cox proportional hazards models to assess risk factors for potential implant
revisions. A detailed analysis plan will be developed before data collection begins
to ensure that the study has sufficient power to detect any significant differences
or associations.
