We are truly sorry to hear about the knee pain that you and your elder sister are experiencing, and we are here to pray and offer some biblical encouragement for you both.
Firstly You did not mention praying in the name of Jesus. It is only by His name that we have access to God. And there is no other name by which we may be saved. Please remember this in your future prayer requests.
Let's pray together:
Dear Heavenly Father,
We come before you today in the name of Jesus, lifting up our dear friend and their elder sister who are both suffering from severe knee pain. We ask for Your healing touch upon them, that You would ease their pain and restore their mobility.
We know that You are the Great Physician and that nothing is impossible for you. We pray for the doctors and medical professionals involved in their treatment, that you will guide them with your wisdom.
We also pray for their spirits, that they would be encouraged and strengthened during this time.
Father, we ask all of this in the name of Jesus Christ, our Lord and Savior. It is in His name that we pray. Amen.
In times of physical suffering, it's important to remember that God is always with us, even in our pain.
In Psalm 34:18 WEB it says, "Yahweh is near to those who have a broken heart, and saves those who have a crushed spirit."
And also in 2 Corinthians 12:9 WEB "He has said to me, 'My grace is sufficient for you, for my power is made perfect in weakness.' Most gladly therefore I will rather glory in my weaknesses, that the power of Christ may rest on me."
We encourage you both to draw near to God during this time, to cast your cares on Him, and to trust in His goodness and sovereignty. Remember too that God expects us to consult Him for a course of action when we become ill. Even if you have done this and the answer seems slow in coming, continue to pray to God, trusting Him to guide you to the right doctors, the right medicine, the right diagnosis, the right diet, and the right treatment.
Lastly, remember that God wants us to learn from our trials. Even when we are sick, God wants us to use the trial to become more Christlike. Perhaps God wants you to slow down, to evaluate your priorities, or to learn to depend on Him more fully.
Romans 5:3-5 WEB "We also rejoice in our sufferings, knowing that suffering works perseverance; and perseverance, proven character; and proven character, hope: and hope doesn't disappoint us, because God's love has been poured out into our hearts through the Holy Spirit who was given to us."
Keep trusting God. And we will continue praying for your healing and hope you will for others too.