The goal of this clinical trial is to look at how well different surgeries heal over time in patients that have previously undergone arthroscopic knee interventions. These procedures may include cartilage repair or grafting, meniscus repair or trimming, ligament reconstruction, cartilage smoothing, and treatments such as amniotic tissue or platelet rich plasma (PRP).

Using a very small camera called a nanoarthroscope, doctors will take a "second look" inside the knee after surgery to see how it has healed. These findings will be compared to patient-reported outcomes, such as pain and function scores, as well as images taken during the original surgery.

The goal is to determine whether this second look provides useful information that can help guide recovery and future care.

The purpose of this study is to examine the healing potential and mid to long term outcomes of various orthopaedic surgical interventions within the knee joint through a novel modality, bedside nanoarthroscopy. These interventions include but are not limited to: autocartilage grafting, biocartilage grafting, meniscus repair, partial meniscectomy, ligament reconstruction, chondroplasty, as well as amnion placement and platelet rich plasma injection. The "second look" nanoscopic outcomes will be compared to the gold standard patient reported outcome measures as well as time of surgery arthroscopic images.

The individuals recruited for the study will participate in one single clinic visit which will entail a nanoscopic evaluation of their knee. Patients will be asked to fill out a standardized battery of validated patient reported outcome measure surveys and will be consented to undergo a "nanoscopic second look" into their knee joint using a nanoscope in the clinic setting. This procedure involves inserting a nanoscopic camera into the knee joint for diagnostic purposes. The nanoscope is no larger than an 18-gauge needle which is routinely used in clinic and hospital settings to deliver injections and perform arthrocentesis.

For the patients who agree to participate, the following information will be collected from them and from chart review. Injury, procedure performed, date of procedure, and time since procedure. Key images from preoperative MRI will also be accessed along with arthroscopic images from the time of surgery. Nanoscopic images and patient reported outcome measures as described above will also be collected and secured.

Using a comparison of key slices of preoperative MRI, time of surgery arthroscopic images, and nanoscopic second look images, a percentage of healing will be estimated and recorded. This number will then be compared against scores on the patient reported outcome surveys. This will be repeated for all patients enrolled in the study and statistical analysis will be performed to determine if there is a correlation between patient reported outcome scores and percentage of healing at nanoscopic second look.

Secondary outcomes will also be analyzed including success/failure of any biologic augmentation type procedures such as cartilage allograft or autograft and/or amniotic membrane use by comparing time of surgery images to nanoscopic second look images

It will take approximately 2 years to enroll all study subjects and approximately 3 years to complete this study.

Inclusion Criteria:

• Adults aged 18 years and older who have undergone or are scheduled to undergo arthroscopic knee intervention.
• Eligible procedures include meniscus repair, biocartilage procedures, and other arthroscopic biologic interventions of the knee
• Ability to understand and provide informed consent
• Agreement to undergo postoperative in-clinic second-look nanoscopic arthroscopy of the knee.

Exclusion Criteria:

• Refusal to undergo postoperative in-clinic second-look nanoscopic arthroscopy of the knee.
• Inability to provide informed consent.
• Individuals who are not yet adults (infants, children, teenagers).
• Pregnant women
• Prisoners

Individual participant data will not be shared outside of the study team.