Over the years, in the course of orthopaedic clinical and rehabilitation work, we often encountered patients with distal humeral fractures, especially those with intercondylar comminuted fractures, who received ulnar hawk’s-beak osteotomy tension band fixation and distal humeral double plate internal fixation, but their final rehabilitation results were mostly unsatisfactory, and some of these patients would develop heterotopic ossification during the rehabilitation process ( HeterotopicOssification,HO). Is there any relationship between PROM in our rehabilitation program and the development of HO? How should our rehabilitation program be adjusted when a patient develops or suspects HO? How can we improve or enhance our post-operative rehabilitation program compared to those of foreign countries? With these questions in mind, I took our team to study the American Orthopaedic Trauma Society OTA on the management of distal humeral fractures, and I also reviewed the literature on HO of the elbow, which was very rewarding. Of course the answer was eventually found. The use of AROM, PROM, and braces after distal humeral fracture can all be effective in improving elbow function, even if HO occurs, without accelerating and stimulating the development of HO, but avoiding violent distraction! There is debate as to what is the most appropriate and best treatment procedure when a patient presents with Heterotopic Ossification (HO) or suspected HO. Orthopaedic surgeons and therapists often do not advocate PROM (passiverangeofmotion) because they believe that PROM can cause or accelerate the formation of HO. By reviewing the literature, only 3 scientific studies were found. These 3 studies all produced heterotopic ossification by daily violent (forcible) passive activity on braked joints in rabbits. In two of these studies Michelson concluded that ”jointsshouldbeexercisedverycarefullyduringandafteranimmobilizationperiod. ”. Many scholars have concluded that PROM is a contraindication to HO based on these studies because it can lead to the development of HO. This conclusion has misled many people because, after all, PROM is not synonymous with ”forciblepassivemovements.”A retrospective Thompson and Garcia 1967 study’s conclusions are commonly cited. “passivemotionduringconvalescence(rehabilitation)shouldneverbeused. “Theirstudyobservedthatpatientswhoreceived either passive distraction or constant traction with weight on the elbow joint by the therapist eventually developed ossifying myositis ( MyositisOssification,MO). (PS: MO is a synonym for HO, which is more frequently and accurately used.) Interestingly, patients treated with this passive distraction had stiffness in the elbow joint and required intensive passive distraction, whereas those without stiffness did not require passive distraction. Once again, it was mistakenly assumed that passive distraction would lead to the development of MO. Perhaps those who develop elbow stiffness do so as a result of trauma, and MO occurs as a result of the initial trauma rather than passive stretching. Other articles conclude that PROM is a contraindication to HO and are only uncontrolled (anecdotal) studies. Unfortunately, many physicians and therapists refer to these uncontrolled studies when developing rehabilitation principles. On the other hand, there are some articles that recommend the use of PROM when HO occurs. a prospective study by Stover et al. evaluated whether the aggressivePROM procedure accelerated the development of HO. Their results found no significant difference in the occurrence of HO when receiving aggressive PROM training compared to the control group (minimal treatment.) A retrospective study by Wharton & Morgan reported that ROM did not contribute to the occurrence of HO or increase the severity of HO. Their study found that patients who received passive distraction did not exhibit more HO than those who discontinued passive distraction, and in fact, those who did not receive passive distraction quickly lost mobility and developed ankylosis. “The case of Linan reported on the use of CPM to reestablish bilateral knee motion in a brain-injured patient with early onset of HO, with no change in HO on plain radiographs after 6 weeks. The team of Salter, the inventor of CPM, also performed animal studies using cpm in rabbits with HO from quadriceps injury, and the results did not exacerbate the formation of heterotopic bone. There is also a case report of a patient who developed elbow stiffness with HO at the joint as a result of a traumatic brain injury, who was placed in a serial cast and eventually achieved functional ROM with a stable HO. In conclusion, the use of violent techniques on stiff joints can lead to muscle tears and ossification within the muscle. It is very important to note that there is no scientific evidence that controlled ROM training or bracing can cause HO in the elbow joint, so AROM, PROM and static progressive bracing can all be used in the event of HO.