The answer to whether your employer can refuse to allow you to work, if you have any medical restrictions, such as a lifting limitation or limitation on standing, is controlled by the Americans with Disabilities Act (ADA).  Generally, a no-exceptions rule by an employer that you can’t work if you have any restrictions or you must have a full medical release to return to work is a per se violation of the ADA.   Some cases hold that a “must be cured ” or “100% healed” policy is a per se violation of the ADA because the policy does not allow a case-by-case assessment of an individual’s ability to perform essential functions of the individual’s job, with or without accommodation.  An employer can’t make assumptions about a condition or use stereotypes to decide whether an employee can do a particular job.  The employer must use an indivdualized assessment as to the employee’s actual physical or mental condition to determine if the employee likely could or could not do the job in question.  Likewise, an employer can’t just use a doctor’s opinion as a blanket shield for protection against liability for not doing the individualized assessment.  If the doctor’s opinion is obviously not correct or obviously was not an individualized assessment of the condition on the employee’s ability to do the job, then the employer can still have liability under the ADA.  So, if your employer has an absolute rule that employees must have unrestricted releases to return to work after an illness or injury, the employer is probably in violation of the ADA and you should check with an attorney about your rights.