This is why hip fractures are often "the beginning of the end". When someone over the age of 65 breaks their hip, there is a ~50% chance they'll be dead within a year.
https://www.ncbi.nlm.nih.gov/pubmed/31810636
METHODS: Older adults aged ≥65 years were included if they had an isolated hip fracture, were admitted to hospital between July 2009 and June 2016, inclusive, and were registered to the Victorian Orthopaedic Trauma Outcomes Registry. Mortality up to 12 months (365 days) post-injury, and functional outcomes (Glasgow Outcome Scale-Extended; GOS-E) at 12 months post-injury were examined. Multivariable Cox proportional hazards regression was used to estimate adjusted hazard ratios (aHRs), and multivariable logistic regression was used to identify predictors of living independently compared with severe disability or death on the GOS-E.
RESULTS: 4,912 patients were included, of whom 28% died, 46% had moderate-severe disability, and 26% were living independently 12 months post-injury. Mortality rates were lower in women (aHR=0.56, 95%CI: 0.50, 0.63), and in people injured in a high fall vs low fall (aHR=0.47, 95%CI: 0.31, 0.72). Mortality rates were higher in people in the older age groups (75-84 years: aHR=1.53, 95%CI: 1.21, 1.93; 95+ years: aHR=3.58, 95%CI: 2.68, 4.77), living in areas with the highest level of socioeconomic disadvantage (aHR=1.25, 95%CI: 1.01, 1.55), with a Charlson Comorbidity Index weighting of one (aHR=1.60, 95%CI: 1.36, 1.88) or more than one (aHR=2.21, 95%CI: 1.94, 2.53), whose injury occurred in a residential institution versus at home (aHR=2.63, 95%CI: 1.97, 3.52), that resulted in intensive care unit admission (aHR=1.68, 95%CI: 1.21, 2.32), and in people who did not have surgery versus people who had internal fixation (aHR=1.65, 95%CI: 1.33, 2.04). Independent living was inversely associated with most of the same characteristics; however, people also had lower odds of living independently if they were from metropolitan residential areas versus rural areas (aOR=0.77, 95%CI: 0.62, 0.96), or had mild to moderate (aOR=0.33, 95%CI: 0.27, 0.39) or marked to severe (aOR=0.13, 95%CI: 0.09, 0.20) preinjury disability vs no preinjury disability.
Relatedly, this study from the same institution claims 5% mortality rate after a year for people under 65: https://www.ncbi.nlm.nih.gov/pubmed/27527378
But it does point slightly towards surgery bring beneficial (fixation reduced risk)
This passes the smell test without problem.
My grandfather who rode a bicycle everywhere into his 80s, never owned an automobile (Europe) broke his hip in a minor fall. He was moved to the USA to get the operation and lived with us permanently afterwards, it was definitely the beginning of the end.
Pretty simple way to reverse the osteoporosis.
The main result is prolonging age until occurrence anyway, not prevention. And definitely not cure.
It's just pushing it back a bit, of course she saw some improvement relative to a completely sedentary condition and that's great. It's not going to stay on that trajectory indefinitely, which is what's implied by "reverse".
(I was running down a steep hill and pitched forward onto the pavement face first. I ended up scraping one knuckle, leaving a very tiny scar. Yes, that would probably have looked a lot uglier had I somehow been 65 at the time.)
If that extrapolates out, then you may be right. Because of the demographic that breaks a hip, a shockingly large group of people who break a hip die within a year.