Tunnel convergence in combined anterior cruciate ligament and posterolateral corner reconstruction.

PURPOSE: To examine the geometric relationship between tunnels created in the lateral femoral condyle in reconstruction of the anterior cruciate ligament (ACL) and the posterolateral structures. METHODS: The geometric relationship between a standard ACL tunnel and 11 lateral femoral tunnel variations in synthetic femur specimens was examined. Tunnel collision frequency and tunnel separation were measured radiographically. Subsequent evaluation was performed on 7 paired cadaveric specimens (14 knees) to access the efficacy of 2 configurations. RESULTS: Phase I-Tunnel collision frequency was 0% and 58% for 25-mm and 30-mm tunnel depths, respectively. Axial angles greater than 40 degrees and coronal angles > or =20 degrees resulted in unsafe configurations. The safest position for lateral tunnel placement was straight lateral approach (0 degrees in the coronal plane) with increased axial plane orientation (hand dropped toward the floor 40 degrees). The safe zone for lateral tunnel configuration was determined to be between [0,0] and [0,40] ([coronal, axial]). Phase II--Control group ([0,0]) collision frequencies were 43% and 86% for the 25-mm 30-mm tunnels, respectively. Experimental group ([0,40]) collision frequencies were 29% and 43% for the 25-mm and 30-mm tunnel, respectively. In femoral condyles measuring <35 mm, collision rates were 100% versus 0% in the control group ([0,0]) versus the experimental group ([0,40]). In specimens where no collision was seen, tunnel separation distance was 4.5 +/- 4.4 mm and 5.8 +/- 2.2 mm for the control and experimental groups, respectively (P = .39). CONCLUSIONS: Tunnel collision occurred often. Tunnel collision is dependent on femoral condyle geometry, tunnel depth, and tunnel configuration. To minimize the potential for tunnel collision, the surgeon should maintain a neutral alignment in the coronal plane, limit lateral tunnel depth to < or =25 mm, and direct the lateral tunnel anteriorly in the axial plane to a maximum of 40 degrees. CLINICAL RELEVANCE: This study describes guidelines for tunnel placement to prevent tunnel collision when performing combined ACL and posterolateral corner reconstruction.

Partial tears of the subscapularis tendon found during arthroscopic procedures on the shoulder: a statistical analysis of sixty cases.

BACKGROUND: Prevalence and clinical significance of partial tears of the subscapularis tendon have not been widely studied. PURPOSE: To determine prevalence of and clinical factors associated with partial tears of the subscapularis tendon at arthroscopy. STUDY DESIGN: Case control study. METHODS: During arthroscopic procedures on 314 consecutive shoulders, the arthroscopically visible portion of the subscapularis tendon was probed. Patients with and without partial tears were compared for prospectively identified variables. RESULTS: Partial tears were found in 60 of the 314 patients (19%). Increasing age and dominant arm involvement were significant variables for partial tears. Significantly associated factors included supraspinatus tendon tears (54 of 60; 90%), rotator cuff disease (44 of 60, 73%), and posterosuperior labral fraying (34 of 47, 72%). Increasing age, dominant arm involvement, and coexisting infraspinatus tendon tears were strong independent risk factors for partial tears. CONCLUSION: Partial tears of the subscapularis tendon are not uncommon findings during shoulder arthroscopic procedures and are associated with extensive rotator cuff disease. They do not appear to be associated with glenohumeral instability, but a possible association with atypical forms of instability (subclinical or superior instability) cannot be excluded by this study. The absence of a significant association between the lesion and specific subjective symptoms or physical findings suggests that caution should be taken when attributing a specific symptom to this condition.

A biomechanical evaluation of transcondylar femoral fixation of anterior cruciate ligament grafts.

BACKGROUND: Interference screw fixation of the graft in anterior cruciate ligament reconstruction is considered the gold standard, but limited clinical experience suggests that transcondylar fixation is equally effective. PURPOSE: To compare transcondylar and interference screw fixation. STUDY DESIGN: Ex vivo biomechanical study. METHODS: Twenty pairs of unembalmed knees underwent anterior cruciate ligament reconstruction with patellar tendon autografts. In 1 knee of each pair, the bone plug was stabilized in the femoral tunnel with standard interference screws; in the other knee, transcondylar screws were used. Testing to failure occurred immediately or after 1000 cycles of sinusoidal loading (30 to 150 N) (20 paired reconstructions each). Fixation stiffness, strength, graft creep, displacement amplitude, and change in amplitude were measured and compared (repeated measures anaylsis of variance with Tukey test; P <.05). RESULTS: There was no significant difference in acute strength, maximum load within 3 mm, or stiffness between transcondylar fixation (410 +/- 164 N, 183 +/- 93 N, and 49.6 +/- 28 N/mm, respectively) and interference fixation (497 +/- 216 N, 206 +/- 115 N, and 61 +/- 37.8 N/mm, respectively). Similarly, there was no significant difference in cyclic strength, maximum load within 3 mm, or stiffness between transcondylar fixation (496 +/- 214 N, 357 +/- 82.9 N, and 110 +/- 27.4 N/mm, respectively) and interference fixation (552 +/- 233 N, 357 +/- 76.2 N, and 112 +/- 26.8 N/mm, respectively). Predominant modes of failure were bone plug pullout (transcondylar fixation) and tendon failure or bone plug fracture (interference fixation). CONCLUSIONS: Transcondylar screw fixation of the patellar tendon autograft into the femoral tunnel performed mechanically as well as interference screw fixation. CLINICAL RELEVANCE: The results suggest that transcondylar and interference screws provide similar fixation for anterior cruciate ligament reconstruction.

Pigmented villonodular synovitis of the knee: average five-year follow-up of arthroscopic treatment.

We have reviewed the results of arthroscopic treatment of pigmented villonodular synovitis (PVNS) with reference to both recurrence and to function. Between 1985 and 1995, a single surgeon treated eight patients. At an average 5-year follow-up, all patients were interviewed and had assessment of Hospital for Special Surgery (HSS) knee score for both the affected and unaffected knees. Also recorded were age, sex, and whether disease was recurrent, localized, or diffuse. Disease recurred in 4 patients, all with diffuse PVNS, and 3 of them required a further arthroscopic synovectomy at a mean of 16 months after the index procedure. All patients had good or excellent functional results. There was no significant difference between HSS knee scores for affected and unaffected knees. Arthroscopic synovectomy is a successful treatment in patients with localized PVNS of the knee and results in a knee that is functionally not different from its unaffected partner.