The treatment gap between conservative management and total knee arthroplasty may leave patients with moderate cases of knee osteoarthritis (OA) without an ideal treatment option. The KineSpring® Knee Implant System may be a viable treatment option to fill the treatment gap for patients with knee OA who are not willing or inappropriate candidates for total knee arthroplasty, yet do not demonstrate relief with conservative treatments. This current paper reports a series of patients who received the KineSpring System and were followed for five years. Twelve patients were included in the case series. All 12 patients were diagnosed with symptomatic OA of the medial compartment of the knee. Pain and functional problems associated with OA improved with treatment using the KineSpring System. Furthermore, these improvements were seen over the course of five years. The findings of this study show the KineSpring System as a promising intervention for early-onset OA and warrant further investigation regarding its effectiveness.