Developing robotic tools that introduce substantial changes in the surgical workflow is challenging because quantitative requirements are missing. Experiments on cadavers can provide valuable information to derive workspace requirements, tool size, and surgical workflow. This work aimed to quantify the volume inside the knee joint available for manipulation of minimally invasive robotic surgical tools. In particular, we aim to develop a novel procedure for minimally invasive unicompartmental knee arthroplasty (UKA) using a robotic laser-cutting tool. Methods: Contrast solution was injected into nine cadaveric knees and computed tomography scans were performed to evaluate the tool manipulation volume inside the knee joints. The volume and distribution of the contrast solution inside the knee joints were analyzed with respect to the femur, tibia, and the anatomical locations that need to be reached by a laser-cutting tool to perform bone resection for a standard UKA implant. Results: Quantitative information was determined about the tool manipulation volume inside these nine knee joints and its distribution around the cutting lines required for a standard implant. Conclusion: Based on the volume distribution, we could suggest a possible workflow for minimally invasive UKA, which provides a large manipulation volume, and deducted that for the proposed workflow, an instrument with a thickness of 5-8 mm should be feasible. Significance: We present quantitative information on the three-dimensional distribution of the maximally available volume inside the knee joint. Such quantitative information lays the basis for developing surgical tools that introduce substantial changes in the surgical workflow.

The purpose of this study was to quantify limitations in sagittal ankle range of motion (ROM) at least 2 years after lateral column lengthening osteotomy of the calcaneus (LLC) and their implications regarding quality of life. MethodsFifteen patients with a mean follow-up of 80±27 months after LLC and 15 age-matched healthy persons participated in this study. Ankle joint complex ROM in plantarflexion and dorsiflexion was measured bilaterally using a goniometer and fluoroscopy (patients only).Quality of life was assessed using the short-form health questionnaire (SF36). Differences in ROM parameters (for the tibiotalar and subtalar joint) between sides (affected vs. unaffected) and between groups (patient vs. controls) and the relationship between ROM parameters and quality of life scores were assessed. ResultsROM of the ankle joint complex on the affected side in patients was smaller than on the contralateral side (goniometer and fluoroscopy) and in healthy persons (goniometer; all P<.05). Among patients, SF36 total and pain scores, respectively, correlated with ROM of the subtalar joint (fluoroscopy; R=0.379, P=0.039 and R=0.537, P=0.001). Among patients and healthy persons, those with smaller dorsiflexion (goniometer) had lower quality of life scores. ConclusionsThe smaller sagittal ROM of the affected ankle joint complex compared to the contralateral foot and healthy controls was mainly explained by limitations in the tibiotalar joint. Because of its association with quality of life, ROM should be considered in the treatment and rehabilitation planning in patients who are candidates for LLC.

No abstract

No abstract

No abstract