What should make you get checked soon

Yes and no: some hip and knee symptoms can be watched briefly, but certain patterns should be checked sooner rather than brushed off. After a knee pivot, cut, awkward landing or twist, earlier assessment is sensible if there is a "pop", rapid swelling, or a feeling that the knee gives way. AAOS notes that many ACL injuries happen without a direct blow, and NHS and AAOS guidance on meniscus tears notes that people may still walk at first, with stiffness and swelling building over 2 to 3 days rather than immediately.

A knee that locks, keeps catching, or will not fully straighten is a different pathway from a vague ache and usually needs earlier review. At the hip, pain felt only when lying on one side can be positional, but persistent night pain with groin or thigh pain, stiffness, and difficulty walking, rising from a chair or bending is more consistent with hip osteoarthritis. NHS guidance advises assessment when joint pain or stiffness is not going away, especially if function is worsening or symptoms are not settling after sensible self-care or physiotherapy. Investigation is not driven by scans alone: the story and examination come first, with tests such as Lachman or pivot-shift in the knee, and imaging added when it helps clarify the diagnosis.

Could you tear your ACL and miss it at first

Not every ACL injury is recognised straight away. AAOS describes the usual mechanism as a non-contact pivot, cut, twist or landing movement rather than a direct blow, often with a "pop", pain and swelling. The clue that keeps pointing back to the ACL is often a knee that feels unreliable afterwards, especially during turning, sudden stops or on stairs.

In practice, the decision to assess further rests on the pattern of symptoms and the examination. Clinicians use tests such as the Lachman and pivot-shift to look for abnormal laxity, and a 2020 study in 34 people with acute knee trauma found that instrumented laxity testing matched MRI or arthroscopy quite well. In plain terms, a careful hands-on assessment can identify important instability even before a scan confirms the detail. MRI may then help confirm the diagnosis. Repeated giving way, ongoing mistrust of the knee after rehabilitation, or poor confidence with change of direction are sensible reasons for specialist review.

When night hip pain points to osteoarthritis

A hip that hurts at night is not, on its own, a clear sign of osteoarthritis. The Arthritis Foundation notes that pain occurring only in bed is often linked to sleep position or pressure around the side of the hip rather than hip arthritis alone. The pattern becomes more suggestive of hip osteoarthritis when night pain sits alongside groin pain, ache into the thigh or buttock, morning or "start-up" stiffness, and increasing difficulty with everyday tasks such as stairs, longer walks, putting on shoes or socks, or getting up from a chair; that broader functional picture is described by AAOS, NHS and Mayo.

That distinction matters because the aim of assessment is usually to place the hip on the right stage of the pathway, not to leap straight to an operation. OARSI guidance from 2019 supports education and structured land-based exercise as core first-line care for hip osteoarthritis, with activity modification according to symptoms. If pain is regularly waking someone, persisting beyond a short flare, or continuing to limit walking and bending despite that approach, stronger options may be discussed. In a 2024 New England Journal of Medicine trial, adults aged 50 or older with severe hip osteoarthritis already meeting surgical criteria improved more at 6 months after total hip replacement than with resistance training alone, but that was a later-stage group rather than the usual starting point.

When physio may be enough for a meniscus tear

For many degenerative meniscal tears, "structured physiotherapy" is often a sensible first step rather than immediate arthroscopy. Published studies suggest that arthroscopic partial meniscectomy may improve symptoms more quickly for some people, but physical therapy shows comparable longer-term improvement in many degenerative-tear cohorts.

An MRI report also needs context. The decision usually rests on the history, examination and function.

The pathway is different after an acute twist. NHS and AAOS note that a meniscus tear may happen in sport or even with a minor turn while standing, and swelling or stiffness may build over 2 to 3 days rather than straight away; some people can still walk at first. Earlier specialist review matters if the knee is "locked", cannot fully straighten, repeatedly gives way, or pain is affecting sleep or normal activity. A lower threshold also makes sense when there is marked swelling after a fresh injury or concern about a more complex pattern, such as a root tear or combined ligament injury.

What assessment usually involves

A specialist review usually begins with the story of the problem: was there a pivot or jump, a minor twist while standing, or a slower change over months; did swelling appear straight away or over 2 to 3 days; and has the joint started to lock, give way, or limit walking, stairs, bending or rising from a chair. That history guides the examination. In a knee with suspected ACL injury, clinicians may use the Lachman and pivot-shift tests; with a possible meniscal problem, they assess range of movement and whether loss of full extension, catching or locking can be reproduced. In the hip, the pattern of stiffness and reduced movement can be as important as the pain location.

Scans then add detail rather than replacing clinical judgement. In a 2020 study of 34 acute knee injuries, Rolimeter laxity testing showed 91.3% sensitivity, 90.9% specificity and 91.2% accuracy against MRI or arthroscopy, illustrating why examination findings and imaging are often used together. A first consultation does not need to settle surgery on day one. In hip osteoarthritis, the 2019 OARSI guideline places education and structured land-based exercise at the core of early care; in many hip and knee presentations, the initial plan is a working diagnosis, load adjustment, rehabilitation and review.

What to do if symptoms are not settling

Next steps depend less on the label than on how the joint is behaving. After a recent twist, a knee that feels unstable, repeatedly gives way, locks, or will not fully straighten merits assessment rather than open-ended waiting; the same is true when hip pain comes with persistent stiffness and a clear drop in walking, bending, or rising from a chair. If symptoms are milder, a period of activity adjustment and rehabilitation may be reasonable, but lack of progress over the following weeks is a sensible point for review.

The aim of that review is to clarify the diagnosis and guide next steps. The 2019 OARSI guideline places education and structured land-based exercise at the core of hip osteoarthritis care, and similar conservative-first thinking often applies unless the pattern is more urgent. Scans may add useful detail, but decisions usually rest on the history, examination, and how much function has changed.

1. [1] OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis. (2019). https://doi.org/10.1016/j.joca.2019.06.011 https://doi.org/10.1016/j.joca.2019.06.011