Or HaChaim on Exodus 21:19/אור החיים על שמות כ״א:י״ט

1 רק שבתו יתן ורפא ירפא, he shall only pay for loss of income and cause him to be cured completely. This means that even if the victim has regained the ability to get around unassisted but he cannot yet pursue his occupation, the attacker has to continue payments for loss of income. The same applies to continued medical supervision of the victim if the latter deems same as necessary.

2We may understand the word רק as referring to something mentioned by Maimonides in Hilchot Chovel Umazzik. We estimate the cost of medical care as well as the loss of income as soon as the fight is over and the attacker makes these payments immediately. If the estimate proves wrong and the victim takes longer to recover, the attacker is not assessed additional damages. This ruling applies only if the attacker is willing to pay the whole amount of damages immediately. If the attacker preferred to compensate the victim on a day to day basis this limitation on the amount of total damages assessed by the judges does not apply. Maimonides appears to have derived this rule from the word רק in our verse.

3ורפא ירפא. and he will provide full medical services. This too can best be explained by what Maimonides wrote in the above-mentioned chapter of Hilchot Chovel Umazzik. "If the victim said to the attacker: 'pay me cash and I will look for my own doctor, etc.,' one does not take any notice of this." The ruling is derived from the wording in our verse which strongly suggests that the onus of providing medical care is on the attacker personally. This is in contrast to the payment for loss of income where the Torah spoke of the attacker "giving" the payment directly to the victim. There are many other interesting rules which have been derived from the repetition of the words ורפא ירפא.