Joshua A. Baumfeld

Detrimental Effects of Overstuffing or Understuffing with a Radial Head Replacement in the Medial Collateral-Ligament Deficient Elbow

BACKGROUND Comminuted radial head fractures associated with an injury of the medial collateral ligament can be treated with a radial head implant. We hypothesized that lengthening and shortening of the radial neck would alter the kinematics and the pressure through the radiocapitellar joint in the medial collateral ligament-deficient elbow. METHODS The effects of lengthening (2.5 and 5 mm) and shortening (2.5 and 5 mm) of the radial neck were assessed in six human cadaveric upper extremities in which the medial collateral ligament had been surgically released. The three-dimensional spatial orientation of the ulna was recorded during simulated active motion from extension to flexion. Total varus-valgus laxity and ulnar rotation were measured. Radiocapitellar joint pressure was assessed with use of pressure-sensitive film. RESULTS Radial neck lengthening or shortening of >/=2.5 mm significantly changed the kinematics in the medial collateral ligament-deficient elbow. Lengthening caused a significant decrease (p < 0.05) in varus-valgus laxity and ulnar rotation (p < 0.05), with the ulna tracking in varus and external rotation. Shortening caused a significant increase in varus-valgus laxity (p < 0.05) and ulnar rotation (p < 0.05), with the ulna tracking in valgus and internal rotation. The pressure on the radiocapitellar joint was significantly increased after 2.5 mm of lengthening. CONCLUSIONS This study suggests that accurate restoration of radial length is important and that axial understuffing or overstuffing of the radiohumeral joint by >/=2.5 mm alters both elbow kinematics and radiocapitellar pressure. CLINICAL RELEVANCE This in vitro cadaver study indicates that a radial head replacement should be performed with the same level of concern for accuracy and reproducibility of component position and orientation as is appropriate with any other prosthesis.

Predictors for Hamstring Graft Diameter in Anterior Cruciate Ligament Reconstruction

Background The ability to accurately predict the diameter of autograft hamstring tendons has implications for graft choice and fixation devices used in anterior cruciate ligament (ACL) reconstruction. Purpose To determine whether simple anthropometric measurements such as height, mass, body mass index (BMI), age, and gender can be used to accurately predict the diameter of hamstring tendons for ACL reconstruction surgery. Study Design Cohort study (prevalence); Level of evidence, 2. Methods The authors conducted medical record reviews and telephone interviews of 106 consecutive patients with ACL reconstruction using quadrupled semitendinosus-gracilis autograft from 2004 to 2006. Data included anthropometric measurements (height, mass, gender, and age at the time of surgery). Hamstring diameter was obtained using cylindrical sizers in 0.5-mm increments and recorded in the patients surgical record. Correlation coefficients (Pearson r) and stepwise, multiple linear regression were used to determine the relationship between the outcome variable (hamstring graft diameter) and the predictor variables (age, gender, height, mass, and BMI). Independent sample t tests were used to compare hamstring graft diameter between genders. Results Hamstring graft diameter was related to height (r = .36, P < .001), mass (r = .25, P = .005), age (r = —.16, P = .05), and gender (r = —.24, P = .006) but was not related to BMI (P > .05). Height was a statistically significant prediction variable (R2 = .13, P < .001). From the current data, a regression equation was calculated that suggested that a patient <147 cm (58 in) tall is likely to have a quadrupled hamstring graft diameter <7 mm in diameter (graft size = 2.4 + 0.03 × height in cm). Women had significantly smaller hamstring graft diameters (7.5 ± 0.7 mm) than did men (7.9 ± 0.9 mm, P = .01). Conclusions Of the parameters studied, height was the best predictor of hamstring tendon diameter, particularly in women.

Triceps tendon properties and its potential as an autograft

BACKGROUND Although the triceps tendon has been used as a graft for ligament reconstruction about the elbow, and has been postulated to be useful as a graft in the treatment of massive rotator cuff tears, no data exists on the tensile properties of the triceps tendon. The purpose of this study was to define the tensile properties of the medial, lateral, and central thirds of the triceps tendon, in order to examine its potential as an autograft for upper extremity pathology. MATERIALS AND METHODS Ten fresh frozen upper extremity specimens were used. The triceps tendon was dissected from its musculotendinous junction and left attached to its insertion at the olecranon. The tendon was split into thirds and its tensile properties were recorded using a materials testing machine. RESULTS The lateral portion was significantly thinner and less stiff than the medial and central portions (P < .05). It failed at significantly lower ultimate load than the central portion (P < .05). There were no significant differences between the medial, central, and lateral portions of the triceps tendons with regards to ultimate stress (P = .20) or modulus of elasticity (P = .64). CONCLUSION Data from the current study were compared to available literature regarding tensile properties of the rotator cuff and elbow ligaments. Both the medial and central portions of the triceps tendon offer sufficient strength to be used in the reconstruction of the rotator cuff or ligament reconstruction in the elbow.

Joint infection unique to hamstring tendon harvester used during anterior cruciate ligament reconstruction surgery.

Joint infection after anterior cruciate ligament (ACL) reconstruction is a rare but important clinical issue that must be resolved quickly to prevent secondary joint damage and preserve the graft. After careful analysis, we observed 3 infection cases within a 12-month period after ACL reconstruction, which represented an abnormally elevated risk. All reconstructions were performed by the same surgeon and used hamstring tendon allograft. For each surgery, the Target Tendon Harvester (DePuy Mitek, Raynham, MA) was used to harvest hamstring tendons. Through our review, we learned that this instrument was sterilized while assembled. It is our belief that ineffective sterilization of this hamstring graft harvester served as the origin for these infections. We have determined that appropriate sterilization technique involves disassembly of this particular hamstring tendon harvester before sterilization because of the tube-within-a-tube configuration. We have since continued to use the Target Tendon Harvester, disassembling it before sterilization. There have been no infections in the ensuing 12 months during which the surgeon performed over 40 primary ACL reconstructions via hamstring autograft. The information from this report is intended to provide arthroscopists with information about potential sources of infection after ACL reconstruction surgery.

CORR Insights®: Does Combined Intra- and Extraarticular ACL Reconstruction Improve Function and Stability? A Meta-analysis.

I n their meta-analysis, Rezende and colleagues do a good job of evaluating the available evidence on combined intraand extraarticular ACL reconstruction techniques and how those approaches affect function and stability. Although ACL reconstruction is a successful operation, resulting in a high likelihood of return to play, recent data from the Multicenter Orthopaedic Outcomes Network group and others found that its results are not as good as we think, particularly in young patients and high-level (high school and collegiate) athletes [1, 2]. Many patients do not return to activities that they previously participated in, and some studies [1, 2] have found a high frequency of ACL graft rupture and contralateral ACL rupture, particularly in young, active patients in the first 1 to 2 years after reconstruction. In an attempt to improve these results, orthopaedic surgeons have shifted their approach, aiming for more-anatomic reconstructions of the ACL with the use of double-bundle techniques, as well as single-bundle anatomic techniques. There is a renewed interest in the anterolateral ligament of the knee, leading to more studies examining whether this structure should be addressed during surgery [3–5]. Multiple biomechanical studies have been published showing that the anterolateral ligament of the knee helps control internal rotation particularly with flexion of the knee [3, 5]. A clinical study with Level IV data has shown improved postoperative Lysholm and IKDC scores, as well as no pivot shift in 76 patients and Grade 1 in the remaining seven patients [4].