ACL – Stiff

ACL-stiff
Anterior Cruciate Ligament Reconstruction – Postoperative Loss of Motion

Defined as loss of full extension: 5-10o, and or restricted flexion: 120-125o.

Risk Factors:

The most important risk factor appears to be related to the acuteness of reconstruction: numerous reports in the literature describe higher rates of knee stiffness when the surgery is performed within 3 weeks of injury.

Age: older patients tend to have higher rates of stiffness
Male: unexplained
Autograft: bone-patellar-bone grafts injure the extensor mechanism, resulting in pain and quadriceps inhibition. (versus allografts)
Post-operative immobilization: accelerated rehab with emphasis on regaining extension decreases the incidence of stiffness.
Concomitant ligament surgery: especially the MCL – ?enhanced fibrotic response if medial capsular structures operated on as well?

Etiology – multifactorial

Intercondylar notch scarring
Nonanatomic graft placement
Capsulitis / Capsular fibrosis
Concomitant ligament surgery
Infection
RSD

Loss of Extension
Global Loss of Range

Loss of Flexion
– generally not as disabling as loss of extension
– rarely causes functional problems unless the knee fails to flex to at least 120o.
– interferes with running, stair-climbing, squatting, kneeling, sitting

Cyclops Lesions

Term coined by Jackson et al. in 1990 – description of 13 patients out of 230 consecutive patients undergoing patellar tendon autograft reconstruction (incidence of 5%)

– a form of intercondylar notch fibrous proliferation, resulting in a fibrous nodule anterior to and associated with the tibial graft insertion site. The term “cyclops” was coined for the lesion’s headlike appearance and characteristic focal bluish areas of colorations.

– represents a spectrum of reactive tissue
– often associated with a clunk on terminal extension

Etiology
– not completely understood
– nidus stimulated by debris raised from the drilling and preparation of the tibial tunnel. The drill creates an osteo-cartilaginous flap of tissue that may retain some attachments to adjacent intra-articular structures (anterior horn of meniscus, overlying soft tissue, etc). The flap is pulled down into the tunnel when the drill is withdrawn, and thus avoids detection and debridement. It is then pushed up into the knee with the graft, and may serve as a nidus from which granulation and fibrous tissue proliferates.

Histology
– dense, firbous, well-circumscribed nodule of tissue
– centrally located granulation tissue with immature hypercellular fibrous tissue
– peripherally located mature fibrous tissue with parallel collagen, hypocellular matrix.
– occasionally islands of immature bone

Clinical Presentation
– palpable and audible clunk on terminal extension is thought to be pathognomonic
– may be associated with block to extension; generally not painful

Classification (Jackson)
Type 1: terminal clunk only
Type 2: terminal clunk with transient loss of extension that can be overcome with activity
Type 3: large lesion with fixed flexion contracture related to a large (2-4.5 cm) lesion
Type 4: large lesion with global loss of motion related to extensive fibrous proliferation in teh intercondylar notch and associated arthrofibrosis

Treatment
Systematic approach to knee stiffness
Repeat arthroscopy should address all possible pathologies: consider suprapatellar, intercondylar adhesions, graft impingement, patellar fat pad fibrosis
Resect the lesion

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