Reviewed and Approved by Dr Ritwik Kejriwal (Orthopaedic Surgeon)
Over the past few months, a number of physiotherapists have asked me to write more about MCL and medial-sided knee injuries.
That is timely, because our understanding of the medial side of the knee has changed significantly. What was once often thought of as a relatively simple “MCL sprain” is now recognised as a spectrum of injuries involving the superficial MCL, deep MCL and posteromedial structures, each contributing differently to valgus and rotational stability.
Most MCL injuries still heal well
The reassuring message has not changed: most isolated MCL injuries heal successfully without surgery.
The medial ligament complex has good healing potential, and many grade I and II injuries — and a proportion of higher-grade injuries — recover with time, appropriate load management, progressive strengthening and restoration of movement.
For most patients, the initial priorities are straightforward:
restore comfortable range of motion
regain quadriceps strength
progressively normalise gait and loading
rebuild strength and control
gradually return to running, pivoting and sport as stability allows
Why are some MCL injuries more complicated?
The important development over the last decade is recognition that the medial side is more than one ligament.
The superficial MCL is the main restraint to valgus loading. The deep MCL has an important role in controlling external tibial rotation and anteromedial rotatory instability, while the posteromedial complex — including the posterior oblique ligament — contributes to rotational stability, particularly nearer extension.
This matters because a patient may recover from the initial pain and swelling yet still be left with subtle instability if part of the medial-sided injury has healed loosely or an associated rotational injury was not initially recognised.
A small group do not heal completely
The majority of patients progress well.
A smaller group continue to describe symptoms such as:
the knee feeling loose or unreliable
giving way with pivoting or change of direction
difficulty returning to higher-level sport
persistent activity related medial discomfort
a sense that rehabilitation has plateaued despite good strength gains
In my practice, patients referred with this pattern have often already completed several months of rehabilitation and typically present around 6 months to 3 years after their injury.
At that stage, the question is no longer simply “Has the MCL healed?”
It becomes:
Has it healed tightly enough?
Is there residual valgus laxity?
Is there rotational instability?
Is the deep MCL or posteromedial corner involved?
Residual valgus or anteromedial rotatory laxity after an appropriate period of rehabilitation is one of the situations in which further surgical assessment may be appropriate.
When should a physiotherapist consider re-referral?
I would consider reassessment if a patient has completed a good rehabilitation programme but still has:
recurrent instability or giving way
persistent valgus laxity compared with the opposite knee
rotational asymmetry
difficulty returning to pivoting sport or physically demanding work
a clear plateau despite appropriate rehabilitation
The key message
Most MCL injuries heal well. A small proportion heal, but heal loose.
Modern assessment therefore needs to consider the whole medial side of the knee rather than thinking only about the superficial MCL.
In the next article in this series, I’ll look more closely at partially or poorly healed MCL injuries, particularly the deep MCL and anteromedial rotatory instability — and why these patients can remain symptomatic despite apparently successful rehabilitation.
References
Solaro L, et al. Current trends in the medial side of the knee: not only medial collateral ligament (MCL). 2024.
Current concepts in isolated and combined injuries of the medial collateral ligament complex—Part I: Anatomy, biomechanics, clinical and radiological examination. 2026.
Shultz CL, et al. Nonoperative Management, Repair, or Reconstruction of the Medial Collateral Ligament in Combined Anterior Cruciate and Medial Collateral Ligament Injuries—Which Is Best? A Systematic Review and Meta-analysis. Am J Sports Med. 2024.