There are many other injuries that opera singers suffer from. I found in newspapers those examples of accident, which occurred on stage:

At the met

in 1905 at the Met, the bridge across which Carmen was to make her escape suddenly collapsed and sent 15 members of the chorus sprawling.

When Georg Anthes was singing Lohengrin in 1903, his swan-boat upset and flung him flat upon a painted ocean.

In 1924 Curt Taucher, as Siegfried, was climbing the fire-girt rock when he unluckily stepped through a trapdoor.

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We can report an anecdote from Tito Gobbi's memoires: Maria Callas was Tosca, and during the 2nd act she came too near the candles burning on Scarpia's desk and ignited her hair (or wig). Gobbi immediately improvised a raptor-like motion: he jumped on Tosca, embraced her and extinguished the flames. Tosca rejected him with disgust, but then whispered him a "thank you, Tito"... just before killing him.

Also memorable is Placido Domingo's headlong fall while rushing down from the scaffolding during Act 1 of "Tosca live at the real times & places": he smashed into the bottom of the fence of the real Cappella Attavanti, giving a definite hint of realism to the broadcast.

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From the front-page headlines in Italian newspapers: "Cavaradossi has been shot!"...

At the Macerata summer festival on 30 July 1995, the tenor (Fabio Armiliato) was shot in the 3rd act - as usual. But this time when Tosca (Raina Kabaivanska) rushed to him she heard a whisper: "Call an ambulance!...", and then she fainted at the sight of his blood. Because of a blank charged with too much powder, the tow had pierced Cavaradossi's boot and hurt his leg. It is possible that the gun was overcharged because of another accident at the same festival, some years before, when the headlines read: "Cavaradossi dies from heart attack" (the guns did not go off!). Armiliato, after an hour of surgery, said he "had been lucky that the soldier did not aim at the right height". But he should have been grateful to the stage director for not sticking to the realism Puccini wanted: he staged the shooting on a staircase, with the soldier's head at the level of Cavaradossi's feet. (5 days later, going on stage at the beginning of act 2, Armiliato's crutch slipped, causing a double fracture of the other leg...) An even more realistic execution supposedly took place in the first years of Tosca's stage history: in the title role was Lina Cavalieri, known as the "world's most beautiful woman" and known also for her courage and boldness: actually she did not faint when Cavaradossi was really shot to death!

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In an interview in New York in 1935, Florence Eastonshe, suggested the reason for her absence from the Metropolitan Opera: "It was an accident during a performance of Carmen in England a year ago which incapacitated me for a number of months last year. Reeling in Carmen’s death-throes, I happened to catch my heel in the skirt of my dress and fell, twisting my spine, directly in the path of the curtain. The audience hadn't the remotest idea that the apparently lifeless Carmen who lay there was almost lifeless - and indeed, I actually would have been two minutes later if I had not retained sufficient consciousness to edge out of the path of the descending curtain on its way to deposit about a ton of iron weighting on my head. However, all these things must be taken in one’s stride".