Natural History of the ACL-Deficient Knee : Wheeless' Textbook of Orthopaedics

- See: Partial ACL Deficiency:

- Discussion:
- left untreated, the torn ACL leads to anterior laxity, rotatory instabilities, and meniscal tears;
- there is a definite increase in X-ray changes of DJD
- 1/3 of pts w/ isolated ACL injuries will show minimal instability
- 2/3 will show instability;
- patients who intend to return to pre-injury athletic activity level will find that re-injury is common;
- re-injury may occur in over 50% of young patients over one year;
- re-injury may occur in over one third of middle aged patients after one year;
- effects on the menisci: (see ACL and meniscal tears:
- at the time of injury approximately 1/3 of patients will have meniscal tears, which are equally divided between the medial and
lateral compartments;
- the anterior instability produced by the ACL tear often leads to longitudinal meniscal tears in the medial compartment;
- the degenerative arthritis seen in ACL deficient knees may be more related to concomitant meniscal tears than it is to the ACL deficiency;
- effects on chondral surfaces:
- cartilage damage will correlate with length of time from injury;
- medial compartment will often show more damage than the lateral compartment;
- quadriceps avoidance gait: (see: gait)
- most patients will alter their gait in order to avoid anterior displacement of the tibia which occurs with quadriceps contraction;
- between 0 to 45 deg of flexion, contraction of the quadriceps will cause anterior translation of the quadriceps (which is normally
resisted by the ACL);
- maximum anterior translation of the tibia occurs at 15-25 deg of flexion;
- late degenerative changes:
- late degenerative changes are most often seen in ACL deficient knees with meniscal injury;
- ref: Long term osteoarthritic changes in anterior cruciate ligament reconstructed knees.

- Non Operative Treatment:
- there is no good evidence that brace wear decreases the rate of re-injury;
- older patients w/ isolated ligament injury who are willing to moderate their activity will find non-operative treatment to be satisfactory in
the majority of cases (over 80%)

The lower-extremity musculature in chronic symptomatic instability of the anterior cruciate ligament.

Tears of the anterior cruciate ligament in adolescents.

Conservatively treated tears of the anterior cruciate ligament. Long-term results.

Knee function after surgical or nonsurgical treatment of acute rupture of the anterior cruciate ligament: a randomized study with a long-term follow-up period.

Non-operative treatment of the torn anterior cruciate ligament.

Untreated ruptures of the anterior cruciate ligament. A follow-up study.

The anterior cruciate ligament. A functional analysis based on postmortem studies.

The natural history of the meniscus in anterior cruciate insufficiency. Arthroscopic analysis.

Non-operative treatment of ruptures of the anterior cruciate ligament in middle-aged patients. Results after long-term follow-up.

Controversy about treatment of the knee with anterior cruciate laxity.

Anterior-cruciate-insufficient knees treated with physiotherapy. A three-year follow-up study of patients with late diagnosis.

A clinical and radiographical analysis of 127 anterior cruciate insufficient knees.