Six-Month Outcomes of Clinically Relevant Meniscal Injury in a Large-Animal Model

Background: The corrective procedures for meniscal injury are dependent on tear type, severity, and location. Vertical longitudinal tears are common in young and active individuals, but their natural progression and impact on osteoarthritis (OA) development are not known. Root tears are challenging and they often indicate poor outcomes, although the timing and mechanisms of initiation of joint dysfunction are poorly understood, particularly in large-animal and human models. Purpose/Hypothesis: In this study, vertical longitudinal and root tears were made in a large-animal model to determine the progression of joint-wide dysfunction. We hypothesized that OA onset and progression would depend on the extent of injury-based load disruption in the tissue, such that root tears would cause earlier and more severe changes to the joint. Study Design: Controlled laboratory study. Methods: Sham surgeries and procedures to create either vertical longitudinal or root tears were performed in juvenile Yucatan mini pigs through randomized and bilateral arthroscopic procedures. Animals were sacrificed at 1, 3, or 6 months after injury and assessed at the joint and tissue level for evidence of OA. Functional measures of joint load transfer, cartilage indentation mechanics, and meniscal tensile properties were performed, as well as histological evaluation of the cartilage, meniscus, and synovium. Results: Outcomes suggested a progressive and sustained degeneration of the knee joint and meniscus after root tear, as evidenced by histological analysis of the cartilage and meniscus. This occurred in spite of spontaneous reattachment of the root, suggesting that this reattachment did not fully restore the function of the native attachment. In contrast, the vertical longitudinal tear did not cause significant changes to the joint, with only mild differences compared with sham surgery at the 6-month time point. Conclusion: Given that the root tear, which severs circumferential connectivity and load transfer, caused more intense OA compared with the circumferentially stable vertical longitudinal tear, our findings suggest that without timely and mechanically competent fixation, root tears may cause irreversible joint damage. Clinical Relevance: More generally, this new model can serve as a test bed for experimental surgical, scaffold-based, and small molecule–driven interventions after injury to prevent OA progression.

Arthroscopic Repair of Batter’s Shoulder

Background: Batter’s shoulder is a condition in which the posterior labrum is typically torn during the baseball swinging motion, producing a traumatic tear and posterior instability. The injury commonly occurs in the batter’s lead shoulder due to repetitive microtrauma, raising concern for switch-hitters due to the cumulative stress of throwing and swinging on the lead shoulder. Instability is commonly caused by a posterior humeral force and relative shoulder adduction, which is most prevalent during a swing attempt at a low and outside pitch. Indications: Damage to the labrum during the acute traumatic event can cause residual pain and recurrent instability of the shoulder. Indications include failed conservative management. The patient demonstrated a full-thickness longitudinal tear that was grossly unstable with gentle probing. Technique Description: After establishing presence of an unstable posterior labral tear during diagnostic arthroscopy, a 7-o’clock portal is established for the labral repair. A knotless suture anchor construct was utilized for its low-profile features. Care is taken to avoid both tangling of sutures and overtensioning of the repair. Results: Patients return to live batting practice at 6 months postoperatively and most patients return to the same level of play following surgical management. Discussion/Conclusion: Avoid overtightening of labral repair and subsequent loss of range of motion. Use of a low-profile knotless suture anchor is the senior author’s preferred method of surgical management. A majority of patients surgically managed for unstable posterior labral injuries return to the same level of play.

Dislocation of the first metatarsophalangeal joint concomitant with Lisfranc joint dislocation in a 45-year-old man

A 45-year-old man presented with severe pinch-point crush injury to his left foot. Plain radiographs revealed dislocation of the first metatarsophalangeal joint and dorsolateral dislocation of the basal phalanx and sesamoids. The first tarsometatarsal joint was subluxed in the plantar direction and the second to fourth tarsometatarsal joints were subluxed dorsally. The sesamoids were displaced dorsolateral to the metatarsal head. There was a longitudinal tear of the joint capsule at the medial margin of the medial sesamoid, which was sutured together with the abductor hallucis tendon and collateral ligament. The Lisfranc and dorsal ligaments in the tarsometatarsal joint were torn and repaired after reduction and fixed with a plate. One year after surgery, there was contracture of the first metatarsophalangeal joint, but the patient had no pain and was able to run.

Forces at the Anterior Meniscus Attachments Strongly Increase Under Dynamic Knee Joint Loading

Background: The anatomic appearance and biomechanical and clinical importance of the anterior meniscus roots are well described. However, little is known about the loads that act on these attachment structures under physiological joint loads and movements. Hypotheses: As compared with uniaxial loading conditions under static knee flexion angles or at very low flexion-extension speeds, more realistic continuous movement simulations in combination with physiological muscle force simulations lead to significantly higher anterior meniscus attachment forces. This increase is even more pronounced in combination with a longitudinal meniscal tear or after total medial meniscectomy. Study Design: Controlled laboratory study. Methods: A validated Oxford Rig–like knee simulator was used to perform a slow squat, a fast squat, and jump landing maneuvers on 9 cadaveric human knee joints, with and without muscle force simulation. The strains in the anterior medial and lateral meniscal periphery and the respective attachments were determined in 3 states: intact meniscus, medial longitudinal tear, and total medial meniscectomy. To determine the attachment forces, a subsequent in situ tensile test was performed. Results: Muscle force simulation resulted in a significant strain increase at the anterior meniscus attachments of up to 308% ( P < .038) and the anterior meniscal periphery of up to 276%. This corresponded to significantly increased forces ( P < .038) acting in the anteromedial attachment with a maximum force of 140 N, as determined during the jump landing simulation. Meniscus attachment strains and forces were significantly influenced ( P = .008) by the longitudinal tear and meniscectomy during the drop jump simulation. Conclusion: Medial and lateral anterior meniscus attachment strains and forces were significantly increased with physiological muscle force simulation, corroborating our hypothesis. Therefore, in vitro tests applying uniaxial loads combined with static knee flexion angles or very low flexion-extension speeds appear to underestimate meniscus attachment forces. Clinical Relevance: The data of the present study might help to optimize the anchoring of meniscal allografts and artificial meniscal substitutes to the tibial plateau. Furthermore, this is the first in vitro study to indicate reasonable minimum stability requirements regarding the reattachment of torn anterior meniscus roots.

Posterior Ankle Arthroscopy for Osteochondromatosis of the Posterior Ankle Extra-Articular Space with a Longitudinal Tear of Flexor Hallucis Longus

We report a rare case of osteochondromatosis of the posterior ankle extra-articular space with a longitudinal tear of flexor hallucis longus (FHL). A 77-year-old woman was referred to our hospital with an approximately 4-year history of pain and swelling in the right posterior ankle joint without obvious trauma. The pain had worsened in the previous 2 years. On presentation, she had tenderness at the posteromedial and posterolateral ankle. Imaging revealed several ossified loose bodies in the posterior ankle extra-articular space. We removed the loose bodies, performed tenosynovectomy around the FHL, and released the FHL tendon using a posterior arthroscopic technique via standard posterolateral and posteromedial portals. A longitudinal tear and fibrillation were detected in the FHL. The patient was able to return to her daily activities approximately 3 weeks after surgery. At the 1-year follow-up visit, she continued to have minor discomfort and slight swelling on the posteromedial aspect of the right ankle but had no recurrence of the ossified loose bodies. To our knowledge, this is the first report of osteochondromatosis of the posterior ankle extra-articular space with a longitudinal tear of the FHL that was treated by removal of loose bodies, tenosynovectomy around the FHL, and release of the FHL tendon via posterior ankle arthroscopy.