Los Blancos made five signings over the summer, but only three of those had been planned in advance, with Jude Bellingham, Arda Guler and Fran Garcia all moving to the club.
Joselu's arrival on loan from Espanyol came as a consequence of Karim Benzema's surprise departure to Saudi Arabia.
Meanwhile, Kepa Arrizabalaga was brought in on loan from Chelsea after it was revealed that Thibaut Courtois would be missing for potentially all of the 2023-24 campaign due to a serious knee injury.
Brahim Diaz was also brought back from a loan spell at AC Milan to compensate for the departures of Mariano Diaz and Marco Asensio in the final third of the field.
There have been suggestions that Los Blancos could be in the market for more signings in January, but Ortero has said that will not be the case unless there are any further significant injury issues.
"In the winter market, the experience has never been good. There has not been any player in the winter market who would have saved anything. Courtois' loss is well covered. Kepa is a great goalkeeper," Ortero told Blanca Remontada.
"I don't think he'll mind me saying he's not Courtois, but Kepa has covered well. He is showing that he is an increasingly better goalkeeper. Let's see if we can hold out.
"One of the problems that [Carlo] Ancelotti has is that he cannot play all 23 at the same time. What a headache to have a choice. The idea is to hold on unless another injury comes."
Real Madrid currently have five players out of action, with Eder Militao also a long-term absentee, having suffered an ACL injury in the team's season opener.
Guler is yet to make his debut, meanwhile, having picked up a thigh problem when he was on the verge of featuring after recovering from a minor knee operation.
David Alaba has also recently been absent with a groin issue, while Nacho is serving a league suspension, which led to Aurelien Tchouameni lining up as a centre-back in the 4-0 win over Osasuna last time out.
Real Madrid might be planning for a quiet January, but Ortero has confirmed the club's desire to sign Paris Saint-Germain attacker Kylian Mbappe next summer.
Los Blancos could also allegedly bring in a centre-forward, while another central midfielder will be required if both Luka Modric and Toni Kroos leave at the end of the campaign.