Natural History of the ACL-Deficient Knee


- 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.

Gait adaptations by patients who have a deficient anterior cruciate ligament.

Surgical or non-surgical treatment of acute rupture of the anterior cruciate ligament. A randomized study with long-term follow-up.

Acute tears of the anterior cruciate ligament. Surgical versus conservative treatment.

Operative versus non-operative treatment of recent injuries to the ligaments of the knee. A prospective randomized study.

Muscle coordination following rupture of the anterior cruciate ligament. Electromyographic studies of 14 patients.

Non-operative treatment of the torn anterior cruciate ligament.

The role of the lateral extraarticular restraints in the anterior cruciate ligament-deficient knee.

The symptomatic anterior cruciate-deficient knee. Part I: the long-term functional disability in athletically active individuals.

The symptomatic anterior cruciate-deficient knee. Part II: the results of rehabilitation, activity modification, and counseling on functional disability.
  
Followup of the acute nonoperated isolated anterior cruciate ligament tear.

Fate of the ACL-injured patient: A prospective outcome study.   

Coactivation of the hamstrings and quadriceps during extension of the knee

The physiology of mechanoreceptors in the anterior cruciate ligament. An experimental study in decerebrate-spinalised animals.



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Friday, May 4, 2012 12:48 pm