Chapter 68 Proprioception and Anterior Cruciate Ligament Reconstruction
The human ACL has been shown to contain mechanoreceptors including Golgi tendon organs, Pacinian corpuscles, and Ruffini nerve endings.1,2 These receptors contribute to proprioception about the knee joint and are also believed to form part of a reflex arc in which an anterior displacement of the tibia results in hamstring muscle contraction. Such a reflex presumably serves to protect the knee, and the ACL in particular, from such stresses. ACL rupture can therefore be expected to result in disruption or alterations of these pathways.
Using a threshold to detection of passive movement test, Barrack et al3 demonstrated a significantly higher threshold value in ACL deficient limbs compared with the normal contralateral limb in a group of 11 patients tested 3 months following ACL rupture. A group of control subjects showed virtually identical threshold values for both knees. The higher threshold values were attributed to a loss of proprioceptive function. Numerous authors have also described the presence of deficits attributable to loss of proprioception in ACL deficient knees, whereas some authors have shown no differences between injured and contralateral or healthy control subject knees (for review, see Reider et al4). For instance, Pap et al5 found a higher rate of failure to detect passive movement in ACL deficient knees compared with the contralateral knee or healthy control subjects’ knees. However, unlike Barrack et al, they did not find any difference in the threshold to detect passive movement among any of the knees.
Beard et al6 measured the latency of reflex hamstring contraction in response to an anteriorly directed shear force to the upper calf in 30 patients with an ACL rupture. They found significantly greater latencies in the ACL deficient knees compared with the contralateral knees. Interestingly, the frequency of giving-way episodes reported by the patients correlated with the latency differential between their two limbs.
Many authors have evaluated proprioception following ACL reconstruction, but they have reported conflicting results. This may be due in part to the different methodologies employed. Various tests of proprioception have been used (joint position sense, threshold to detect passive movement, reaction time, and stabilometric testing). ACL reconstructed knees have been compared with either the contralateral knee, healthy control subject knees, or in some instances to both. Most studies have evaluated patients at only one time point, although some have followed patients over time from preoperatively to as long as 3.5 years postoperatively. The results of studies that have either used a control group of subjects or provided longitudinal follow-up have been summarized in Tables 68-1 and 68-2.
Table 68-1 Studies Comparing Proprioception Between Patients after Anterior Cruciate Ligament Reconstruction (ACLR) and Controls
| Study | Sample Details | Proprioception Outcome Measure |
|---|---|---|
| ACLR Group Equivalent to Control Group | ||
| Al-Othman, 200415 | 22 ACLR, all male, all PT graft, 1–6 yr post surgery (mean 3.6 yr), 30 controls | Joint position sense (standing position) |
| Ochi et al, 199916 | 23 ACLR, 13M:10F, 22 HS graft, 1 fascia lata graft, minimum 18 mo postsurgery, 14 controls (9M:5F) | Joint position sense |
| Roberts et al, 200017 | 20 ACLR, 15M:5F, all PT grafts, mean 24 mo postsurgery, 19 controls (14M:5F) | Joint position sense |
| Co et al, 199318 | 10 ACLR, 5M:5F; 8 PT grafts, 2 HS grafts, mean 31.6 mo postsurgery, 10 controls (5M:5F) | Joint position sense Threshold to detect passive movement |
| Risberg et al, 199919 | 20 ACLR, 8M:12F, all PT grafts, 11–32 mo postsurgery (mean 24 mo), 10 controls (5M:5F) | Threshold to detect passive movement |
