Mechanics of an anatomical reconstruction for the thumb metacarpophalangeal collateral ligaments.

PURPOSE: This study biomechanically evaluated a technically easy variation of anatomical reconstruction of the thumb metacarpophalangeal (MCP) joint ulnar (UCL) and radial (RCL) collateral ligaments. Based on previous work describing the anatomical origin and insertion of these ligaments, we hypothesized that, using these attachment points, joint stability would be restored without significant loss of MCP flexion. METHODS: The collateral ligaments were isolated in 30 cadaveric thumbs (15 UCLs and 15 RCLs). A cyclical load was applied to the MCP joint to assess flexion, radial/ulnar deviation in neutral, and radial/ulnar deviation in 30° of flexion. The collateral ligaments were detached from the bone while their origin and insertion points were marked. Using these sites, anatomical ligament reconstruction was performed with a palmaris longus tendon graft and interference screw fixation. Cyclical testing was repeated on the reconstructed ligaments. RESULTS: No significant difference was found between intact and reconstructed UCLs when tested for radial deviation in neutral, radial deviation in 30° of flexion, or total MCP flexion. No significant difference was found between intact and reconstructed RCLs when tested for ulnar deviation in neutral, ulnar deviation in 30° of flexion, or total MCP flexion. CONCLUSIONS: Our anatomical reconstruction is simple and restores UCL and RCL anatomy as compared with current techniques in the literature by placing the origin and insertion at their anatomical points with use of an interference screw. Using these anatomical origins and insertions, we were able to restore the MCP flexion and stability seen in an intact ligament. CLINICAL RELEVANCE: Our anatomical reconstruction offers a technically easy option for reconstruction of thumb MCP collateral ligament injuries, restoring joint stability without sacrificing flexion.

Anatomy of the thumb metacarpophalangeal ulnar and radial collateral ligaments.

PURPOSE: To describe the origin and insertion of the ulnar (UCL) and radial collateral ligaments (RCL) of the thumb metacarpophalangeal (MCP) joint. METHODS: We dissected 18 UCLs and 18 RCLs from fresh-frozen human cadaveric thumbs. We removed all soft tissue overlying the MCP joint, isolating the proper collateral ligaments. We detached the collateral ligaments from the bone while marking their origin and insertion points and measured these attachment sites in relation to bony landmarks by digital photo analysis. RESULTS: The center of the UCL origin at the metacarpal was 4.2 mm from the dorsal surface and 5.3 mm from the articular surface. The dorsal aspect of the metacarpal origin site was 2.1 mm from the dorsal edge of the metacarpal. The center of the phalangeal insertion was 2.8 mm from the volar surface and 3.4 mm from the articular surface. The volar aspect of the phalangeal insertion site was 0.7 mm from the volar edge of the phalanx. The center of the RCL origin at the metacarpal was 3.5 mm from the dorsal surface and 3.3 mm from the articular surface. The dorsal aspect of the metacarpal origin site was 1.5 mm from the dorsal edge of the metacarpal. The center of the phalangeal insertion was 2.8 mm from the volar surface and 2.6 mm from the articular surface. The volar aspect of the phalangeal insertion site was 0.5 mm from the volar edge of the phalanx. CONCLUSIONS: Our study accurately defined the origin and insertion sites of the UCL and RCL of the thumb MCP joint. CLINICAL RELEVANCE: An accurate definition of the anatomical origin and insertion points of the thumb MCP UCL and RCL may allow for more successful surgical repair and reconstruction.

MRI evaluation of isolated arthroscopic partial meniscectomy patients at a minimum five-year follow-up.

BACKGROUND: The risk of radiographic knee degeneration after partial or total meniscectomy is well documented, but no prior study has employed cartilage-sensitive MRI technology to assess degenerative changes after meniscectomy. HYPOTHESIS: Arthroscopic partial meniscectomy results in early articular cartilage wear and subchondral bony degeneration, even in the absence of clinical symptoms, and these findings can be evaluated with cartilage-sensitive MRI. STUDY DESIGN: Retrospective cohort. METHODS: Twenty-nine patients (ages: 15-40) who had undergone isolated arthroscopic partial medial or lateral meniscectomy with at least 5-year follow-up were evaluated. All patients had arthroscopically normal articular cartilage at the time of initial meniscectomy. Seventeen patients (18 knees) underwent partial medial meniscectomy (MM) and 12 patients underwent partial lateral meniscectomy (LM) with mean follow-up of 8.4 and 7.1 years, respectively. Follow-up evaluation included physical examination, outcome questionnaires, and cartilage-sensitive MRI examination with modified Outerbridge grading of articular surfaces. RESULTS: Outerbridge grades II-IV were noted in 64% of medial compartment joint surfaces in group MM knees versus 33% of lateral compartment joint surfaces in group LM knees. Abnormal cartilage surfaces (grades II-IV), subchondral sclerosis, and condylar squaring were all significantly more frequent after medial meniscectomy (p < 0.05). Groups MM and LM had no significant differences among outcome scores, which remained excellent in both groups. A significant negative correlation was found between the severity of cartilage wear and functional scoring in the MM group, suggesting that functional disability lags behind early MRI evidence of degeneration. CONCLUSIONS: Despite optimal preoperative prognostic factors and excellent functional outcomes, MRI evidence of early articular cartilage degeneration was present in both partial medial and lateral meniscectomy patients at a minimum 5-year follow-up. Results support the use of cartilage-sensitive MRI as a noninvasive screening technique to evaluate cartilage changes after arthroscopic partial meniscectomy and may help to counsel the high-risk patient in regard to postoperative activity.