[1] In this workers’ compensation action plaintiff argues that the Industrial Commission (Commission) should have found that the ankle injury she suffered on 21 June 1986 was compensable under the Act because it was a direct and natural result of a previous compensable ankle injury. We hold that the Commission’s findings of fact are insufficient because they do not address whether or not plaintiffs injury was caused or related to her earlier injury for which she had been compensated. Accordingly, we vacate and remand for additional findings of fact.
The standard of review in workers’ compensation cases is limited. We may determine only whether the findings of fact are supported by any competent evidence and whether they, in turn, support the Commission’s conclusions of law. Hollar v. Furniture Co., 48 N.C. App. 489, 269 S.E. 2d 667 (1980). If, however, the Commission’s findings of fact do not determine all of the issues arising from the action, we must remand the case to the Industrial Commission for additional findings. Thomason v. Cab Co., 235 N.C. 602, 70 S.E. 2d 706 (1952).
Plaintiff argues that the ankle injury she suffered on 21 June 1986 was a direct result of an earlier work related injury. Her first injury occurred on 5 July 1983 when she fell from a milk crate while stocking shelves at defendant’s store. Plaintiff testified that she severely sprained her ankle and received workers’ compensation benefits for her injuries caused by this fall. She contends that this first injury never properly healed because of numerous subsequent ankle sprains. Further, her doctor, Dr. *594Maultsby, stated that these later sprains were directly related “to some instability that [plaintiff] had in her ankle from her first injury.” Dr. Maultsby also observed that once a person sprains an ankle it requires “little provocation” to resprain it. Plaintiff contends that this evidence shows that her 21 June 1986 injury was directly caused by her 5 July 1983 injury.
In Starr v. Paper Co., 8 N.C. App. 604, 612, 175 S.E. 2d 342, 347, cert. denied, 277 N.C. 112 (1970), we held “that a subsequent injury, whether an aggravation of the original injury or a new and distinct injury, is compensable if it is the direct and natural result of a compensable primary injury.” See also Heatherly v. Montgomery Components, Inc., 71 N.C. App. 377, 323 S.E. 2d 29 (1984), disc. rev. denied, 313 N.C. 329, 327 S.E. 2d 890 (1985). Here plaintiff presented sufficient evidence that a fact finder might determine that the 5 July 1983 injury was the proximate cause of the 21 June 1986 injury. A finding in plaintiffs favor on this issue would entitle her to workers’ compensation benefits irrespective of the other issues raised here. The Commission’s findings of fact, however, are silent on the proximate cause issue. Accordingly, we vacate and remand to the Industrial Commission for additional findings of fact.
[2] Defendant further argues that plaintiffs action is a request for a change of condition regarding her 5 July 1983 injury and, therefore, is barred because it was not timely brought pursuant to G.S. 97-47. Assuming arguendo that G.S. 97-47 applies, we hold that defendant may not raise this technical defense for the first time on appeal. This defense must be affirmatively raised prior to a hearing on the merits or it is waived. Gragg v. Harris & Son, 54 N.C. App. 607, 284 S.E. 2d 183 (1981). Our holding here makes it unnecessary to address plaintiffs additional assignment of error.
Vacate and remand.
Judges BECTON and Greene concur.